63

4) Maintenance process and technical quality standards

Before all the maintenance work, the power should be cut off to make good security work as per relevant

safety regulations.

a. Maintenance of parts inside the bin

Rinse the inclined plate assembly with water of some pressure. Hang out half of the inclined plate assembly

of bin, set up a straight ladder for direct access into the bin, rinse out the ash deposits at bottom of bin,

maintain the harrow rotation device and replace worn harrow teeth. Hang out the other half of the inclined

plate assembly of bin, set it on the flat floor, then maintain the inclined plate assembly and replace the

damaged plate.

b. Maintenance of driver and harrow lifting device

Remove the dynamic and control power cord, with attention to the wire markings for easy connection. Fix

the pad on the end of ash scraping harrow shaft at the bottom of bin with channel steel, and then remove the

connecting bolts, step the harrow shaft out of the drive shaft. During assembly, follow the reverse sequence

to disassembly, with reference to the Drawing BXKDOT.GNJTB3.0B-WT and mount each part in place.

Note that all the lubricating parts should be painted with molybdenum disulfide grease and make sure the

concentricity between the output shaft of reducer and worm shaft is within 0.2mm.

5) Commissioning and trial operation after Maintenance

a. Check that there is no debris in the bin.

b. Check that all the connection bolts are in good fastening without loose.

c. Check that the electrical control device is correct.

d. Check that all the lubricated parts have been filled with lubricating oil as required.

e. Check that valves are good and ready to work.

f. Start the harrow lifting motor, observe that the harrow lifting reducer’s lifting and lowering action are

normal and control is accurate and reliable.

g. Start the harrow rotation motor, and observe that the rotation reducer and gear worm reducer are running

in correct direction and operating normally. Trail run with no load should not be less than 4 hours, with the

bearing temperature less than 85 and no-load noise ≤ 85db.

62

maintenance.

10) The slurry discharge port should not be blocked but should be guaranteed of continuous discharge.

11) In case of power failure that results in shutdown, it is required to timely recover the operation of

concentrator. As it starts, if there is any overload protection action, it indicates that the ash and slag deposits

in pool are excessive and need to be cleaned up in order to reduce the startup load; it should not be forced

to start to prevent damage to the parts.

3.1.3 Maintenance

1) Maintenance period: minor maintenance period is 1 year. Overhaul period is 3 years.

2) Minor maintenance items

a. Clean and check the inclined concentration plate assembly, and replace the worn PVC inclined plate.

b. Check the bin bottom ash scrapping harrow rotation part and check the bottom nozzle for blockage, and

remove the blockage if any.

c. Check the drive and harrow lifting motor reducer as per the requirements in the “Operation &

Maintenance Instructions” of Jiangsu Taixing Reducer Factory.

d. Check the torque sensor instrumentation, if any abnormality, contact the manufacturer Beijing Sanjing

Creation Science & Technology Group Co., Ltd.

e. Check and clean up the main shaft bearing, and replace damaged bearings.

f. Check the gear worm reducer housing and main shaft oil seal to eliminate leakage of oil and change

lubricating oil.

g. Check and fasten all the bolts on each part.

3) Safety measures provided before maintenance

Prevent falling objects at height The cover of lifting eye for hanging accessories must immediately reset after the use

Slide and fall to get injury on work site Wear non-slip shoes, and promptly clean up any oil stain on floor

Personal injury Properly use safety protective equipment Scald Make good isolation measures for the equipment that had fire work.

Lifting heavy to enter the bumps

Tie up firmly, and lift up smoothly, with angular pad rubber board on the place where wire rope is hung, and prohibit using # 8 wire rope to lift up accessories

Non-staff bruise in access Set up barrier outside of the workplace

Chain block Check before use, and make sure the conformity certificate is complete and effective.

Wire rope Check before use, and make sure no broken strand.

Power cord, electric tools Make sure the conformity certificate is complete, power cord is not damaged and insulation is qualified Connect the leakage protection, and test it before use.

Electric welding Wear protective equipment to prevent burns and electric shock;

Gas cutting Wear protective equipment, assign special person for safeguard as working at high rise to prevent burns, fire or explosion;

Electric hoist Check wire rope for broken strand, whether the limit switches are complete and reliable, and the operation handle is accurate;

High-rise operation Check seat belt before, tie it and hang tightly; Safety regulations Operators should comply with the work safety regulations.

61

treatment and discharge of slurry or pauses operation for too long time or the content of ash and slag in

incoming slurry increases suddenly which results in pressure on the ash scrapping harrow, system

resistance over limit or dynamic overload, when the torque instrument makes a signal, the harrow lifting

motor will start working, gear transmits to drive the screw to rise, so that the complete harrow rotation

assembly will automatically lift for the purpose of unloading and reduction of load. This device is arranged

on the bin roof platform, with very easy installation, repair, and maintenance. The drive harrow rotation

device should run continuously, and automatic harrow lifting device runs intermittently.

f. The inclined concentration plate assembly is assembled with polymer plastic panels and steel frames that

have good corrosion resistance, high strength, smooth surface and long life on site according to the sample

part, evenly placed in the middle part, acting as the main component for accelerating the ash slurry settling

and improving the efficiency of concentration.

h. The flow stabilizer is set in the center of bin and welded on the roof platform, mainly playing the

function to change the direction of ash slurry water flow, stabilize the divergent flow, and enhance the

effect of settling, and also support the inclined concentration plate assembly.

i. The roof lifting device is set on the bin platform, composed of lifting brackets, beams, rails, electric hoist,

etc. mainly for lifting of such parts as reducer for maintenance.

3.1.2 Operating maintenance and precautions

1) Reducer oil change: the oil should be replaced after running for 150 hours for the first time, the oil

change should be done as the reducer is warm and cleaned, thereafter, the oil can be changed once every 3

~ 6 months; the oil change interval may be shortened appropriately in case of much higher ambient

temperature or humidity. The reducer should be stopped if the oil temperature is found significantly

increased, temperature rise exceeded 60 or oil temperature exceeded 85 , as well as unusual noise or

abnormality is found, and can only be used once again with oil changed after fault is removed.

2) The central drive harrow rotation device should have a trial run after mechanical inspection, and it can

only be put into operated with load after it is normal in operation with no load.

3) It is prohibited to allow large hard materials or other rods, blocks and other debris entering the bin to

block slurry discharge, jamming harrow rotation and affecting normal working of the central drive harrow

rotation device, or even damage the parts.

4) The floating beads or slag on the water surface in the concentrator bin should be promptly removed to

the quality of overflow water and to reduce the load on the inclined plate rack after the concentrator

draining water.

5) Because of different viscosity of ash, the inclined plate surface should be rinsed regularly if any sticky

ash, so as not to affect the overflow water quality and increase the load on the inclined plate and bracket.

6) Do not let the inclined plate exposed under shine for long, nor let step on it to avoid damage. The

concentrator should be filled with water for long outage.

7) It is prohibited to load any person or material on the inclined plate rack.

8) In case rain or snow, the central drive unit motor should be protected with snow or rain shield on the

upper part by user.

9) Concentrator should be provided with specially-assigned perform for operation, routine inspection and

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Chapter 3 Routine Maintenance of Slag Handling System

3.1 High-efficiency concentrator

Structural diagram of high-efficiency concentrator

3.1.1 YD.GNJ15TB.0 High-efficiency concentrator is mainly composed of steel support, ladder, roof

platform, bin body, drive unit, ash scrapping harrow rotation device, inclined concentration plate assembly,

flow stabilizer, bin roof lifting device, etc. parts, with the following structural and performance

characteristics:

a. Steel support is made of section steel that is welded into columns and bracing parts, etc. in manufactory

and welded into the integral unit on site, acting as the support of the concentrator.

b. Ladders and roof platform are welded by section steel, paved with tread plate or steel grating, according

to user’s different requirements, acting as the access and maintenance platform.

c. The bin body consists of upper cylindrical segment and lower cone segment. The cylindrical segment is

welded on site into an integral unit by cylindrical wall board and pilaster that acts as both wall board and

support, its upper part has a serrated overflow weir, for convenience in outflow of the gathered clarified

water. It is welded with a prop ring plate on the middle part on which the inclined concentration plate

assembly is placed and which also supports the inclined concentration plate assembly together with the

flow stabilizer. The cone segment consists of two cone and several pieces of high dimensional accuracy,

accurate forming cone plates that are cut by CNC flame cutter and welded into an integral unit on site.

There are 3 flooding nozzles at the upconing at the slurry discharge port of lower cone row, which run

intermittently, generally work once a day, and 10 minutes each time to prevent blockage of the slurry

discharge port.

d. Drive and automatic lifting device. The high-efficiency concentrator made by Qingdao Daneng

Company uses universal motor directly connected to the cycloid reducer, torque meter connected to the

worm gear to drive the harrow assembly to revolute to scrap mud. When the concentrator runs unsmooth in

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draining water.

5) Because of different viscosity of ash, the inclined plate surface should be rinsed regularly if any sticky

ash, so as not to affect the overflow water quality and increase the load on the inclined plate and bracket.

6) Do not let the inclined plate exposed under shine for long, nor let step on it to avoid damage. The

concentrator should be filled with water for long outage.

7) It is prohibited to load any person or material on the inclined plate rack.

8) In case rain or snow, the central drive unit motor should be protected with snow or rain shield on the

upper part by user.

9) Concentrator should be provided with specially-assigned perform for operation, routine inspection and

maintenance.

10) The slurry discharge port should not be blocked but should be guaranteed of continuous discharge.

11) In case of power failure that results in shutdown, it is required to timely recover the operation of

concentrator. As it starts, if there is any overload protection action, it indicates that the ash and slag deposits

in pool are excessive and need to be cleaned up in order to reduce the startup load; it should not be forced

to start to prevent damage to the parts.

58

slurry discharge valve at the bottom of concentrator tank, rotary harrow scraps and gathers the concentrated

slurry to the slurry discharge port for discharge, then it can be put into stable operation.

8) Equipment is running in continuous mode. The slurry discharge port should continuously discharge

slurry without blockage.

9) During operation of the equipment, if the lifting motor starts to run and ash scraping harrow rises up, it

indicates the ash content in slurry is too high, it should increase the discharge flow of the bottom slurry

discharge port to exhaust the thick slurry at bottom and restore normal operating conditions of equipment.

At the same time, it also should check the ash content of the incoming slurry, and take measures to prevent

too much ash into the high-efficiency concentrator.

10) Before shutdown, the slurry inlet valve should be closed, and the concentrator should be shut down

after the discharge of settled and concentrated slurry particles.

11) Before startup of equipment after long outage for some reason, it should first check for debris or muds

stuck on harrow, and clean up if any to reduce the starting load. The equipment should not be forced to start

with load.

2.1.3Concentrator put-in

1) Close the valve of slurry discharge port at the bottom of concentrator tank, start the harrow rotating

motor and open the valve of slurry inlet pipe to fill the concentrator bin with water or slurry.

2) When the water level in bin is close to the weir overflow, open the slurry discharge valve at the bottom

of concentrator tank, rotary harrow scraps and gathers the concentrated slurry to the slurry discharge port

for discharge, then it can be put into stable operation.

3) The slurry discharge port should continuously discharge slurry without blockage. The flooding nozzle at

the slurry discharge port should be opened regularly, generally once per shift, about 10 minutes.

The high-efficiency concentrator must use continuous operation mode. Before shutdown of high-efficiency

concentrator, the ash and slag stuck on the settling board at the bottom of tank must be cleaned up in order

to ensure the normal operation of high-efficiency concentrator.

2.1.4 Operating maintenance and precautions

1) Reducer oil change: the oil should be replaced after running for 150 hours for the first time, the oil

change should be done as the reducer is warm and cleaned, thereafter, the oil can be changed once every 3

~ 6 months; the oil change interval may be shortened appropriately in case of much higher ambient

temperature or humidity. The reducer should be stopped if the oil temperature is found significantly

increased, temperature rise exceeded 60 or oil temperature exceeded 85 , as well as unusual noise or

abnormality is found, and can only be used once again with oil changed after fault is removed.

2) The central drive harrow rotation device should have a trial run after mechanical inspection, and it can

only be put into operated with load after it is normal in operation with no load.

3) It is prohibited to allow large hard materials or other rods, blocks and other debris entering the bin to

block slurry discharge, jamming harrow rotation and affecting normal working of the central drive harrow

rotation device, or even damage the parts.

4) The floating beads or slag on the water surface in the concentrator bin should be promptly removed to

the quality of overflow water and to reduce the load on the inclined plate rack after the concentrator

57

Chapter 2 Running of Slag Handling System 2.1 Operating principle of high-efficiency concentrator

2.1.1 The high-efficiency concentrator makes use of the deposition characteristics of ash and slag particles

in the liquid to separate solids from liquid, and also makes use inclined concentration plate to accelerate the

sedimentation, significantly improving settling efficiency; solid particles settled to the bottom of tank are

gathered by the bottom rotary ash scraping harrow to the central slurry discharge port at the bottom of tank.

Precipitated slurry of the discharge of high-concentration slurry and the recycling of clarified water. Then

the high-concentration slurry is re-conveyed to the dewatering bin, etc. superior equipment for further

dehydration. The concentration process is: slurry flows into the concentration tank via inlet pipe, quickly

dispersed throughout the cross-section by means of the flow stabilizer under conditions of minimizing

disturbance; coarse ash particles directly sank to the bottom, smaller particles spread around, settling and

diffusing at the same time; and also flow through inclined concentration plate with improved settlement

efficiency. Installation of inclined concentration plate is use of the fluid shouldow theory, the principle is:

(1) increasing the settling area; (2) the settling zone of inclined concentration plate is divided into many

small portions, so the flow is relatively stable, unease to produce vortex, and conducive to particle

sedimentation; (3) the particle sedimentation distance is shorter, which is equivalent to the distance

between two adjacent inclined plates, and therefore the time required of settlement is shorter, settling slurry

particles decline along the inclined plate, i.e. increase settling velocity, improve the settling efficiency. In

this way, the solids in slurry by own gravity sink in a fairly steady medium, the upper water separates from

solid phase, the solid phase slurry particles concentrated in the lower layer and gradually concentrated to

the bottom, they accumulate and being close to each other at the bottom of tank, in the meanwhile, under

the action of the scraper on the rotating harrow frame, the settled solid phase slurry particles further

accumulate and ion of concentrate, and then the precipitated slurry particles are slowly scrapped to the

center of tank by the scrapper on harrow frame to be discharged via the slurry discharge port; there formed

a upper layer of clarified water that flows out along the overflow groove to complete the whole process of

concentration.

2.1.2 Running operation requirements

1) Before running, check that all the bolts have good and tight connections, and whether all the piping and

valves are in starting state.

2) Before running, check whether the reducer has been filled with lubricating oil as required.

3) Before running, check that the motor reducer’s electrical control is normal.

4) Before running, check that the motor reducer is normal in empty running test, and check and verify that

the motor wiring is correct, you must make the rotating direction of reducer output shaft consistent with the

that of the ash scrapping harrow as shown on the general drawing of equipment.

5) Check that there should be no rod, block and other debris in bin, and prevent jamming the harrow

rotation and blocking the slurry discharge pipeline.

6) Close the slurry outlet valve at the bottom of concentrator bin, start the motor reducer, open the valve of

slurry inlet pipe to fill the concentrator bin with water or slurry.

7) When the water level in bin is close to the weir overflow (open swirl nozzle water supply valve) open the

56

1.2.23 Vibrating feeder

Manufacture Type Quantity 3 set/bin Output 80~100 t/h Motor power 11 kW Service life 10000 H Weight ~400 Kg

1.2.24 Biaxial agitating device

Manufacture STATE GRID FUTONG Type JSL-100 Quantity 1 set/bin Output 100 m3/ h Motor power 22 Kw Required Water flow: ~15 m3/h Required water pressure: 0.3~0.6 Mpa Material of wearing parts Iron-based wear-resistant alloy Service life 10000 H Weight 4.5 T

1.2.25 Bag dust collector

No. Item Parameter Remarks 1 Type Pulse jet 2 Quantity 1 set Each boiler 3 Air treatment capacity 16m3/min 4 Filtration air speed 0.8m/min 5 Filtration area 20m2 6 Filter bag quantity and size 24 pcs/ Ø 130×2100mm

7 Filter bag withstand temperature Normal temperature 150 Impact temperature 200

8 Bag life 18000h 9 Filter bag resistance 1200Pa 10 Concentration of dust emission ≤50mg/m3 11 Dusting fan flow 20m3/min 12 Dusting fan pressure head 2500Pa 13 Dusting fan life 18000h 14 Manufacturer STATE GRID FUTONG

55

Type of sealing Labyrinth Crushed particle size 30×30 mm Gear form Involute Teeth roll material High manganese alloy Cutting board material High manganese alloy Operating temperature of the slag crusher 300 Motor power 2×37 kW Motor supply voltage 415 V IP IP54 Service life 24000 h Overall weight 7.5 t

1.2.20 Bucket elevator

Manufacture STATE GRID FUTONG Quantity 2 set/boiler Model FLNE50 Design output 60 t/h Motor model Y160-4 Motor power 15 kW Reducer model ZLYNZ160-46 Max operating temperature of bucket elevator 250 Running speed of the chain bucket 30 m/min Chain bucket specifications (chord length X width) 320×400 mm Lifting height ~26 m Overall weight ~13 t

1.2.21 Bag dust collector

Manufacture STATE GRID FUTONG Quantity 1 set/bin Model DMC-170 Separation efficiency 99.9 % Bag service life 10000 H Operating pressure range 1800 Pa Bag dust collector flow rate 0.8 m/min Bag dust collector area ≥140 m2 Bag material/operating temperature NOMEX/300 Filter bag specifications/quantity Ø130X2000/168 Pulse cleaning air consumption 0.53 m3/min Pulse cleaning air pressure 0.5~0.7 Mpa Pulse controller DMK-21-3CS Dusting fan 9-19A Solenoid valve model ASCO Solenoid valve quantity 21

Differential pressure transmitter Shanghai Instrument Factory No.3

Vacuum gauge YZ-60

1.2.22 Slag bin and its equipment

Effective volume of slag bin 800 m3 Quantity of slag bin 1 set/2 boilers Slag bin diameter Ø10000 Mm Slag bin manufacturer STATE GRID FUTONG Slag bin design temperature 200

Type, model and manufacture of slag level meter Tuning fork /E+H radar wave/Milltronics

Quantity of slag level meter 3 Service life of slag level meter 10000 H Quantity of slag bin shaker 3

54

1.2.17 Bottom slag discharge device

Manufacture STATE GRID FUTONG Quantity (each boiler) 1 Model GPZP14 Drive mode Hydraulic Type Back to back Unit Quantity 12 Cylinder stroke 720 mm Cylinder thrust 80 kN Oil pressure 11 Mpa Motor model Y112M4 Motor power (2 sets) 2×5.5 kW Motor Supply Voltage 415 V IP IP55 Dimensions 5000×3100×3200 mm Proper material Heat-resistant stainless steel Proper thickness 300 Max temperature 800 Structural features Gear form

1.2.18 Dry slag conveyor

Manufacture STATE GRID FUTONG Quantity 1 set/boiler Model GPZS14 Drive mode Friction drive Rated output 15~34.4 t/h Max output 51.4 t/h Rated output slag discharge temperature 100 0C Max output slag discharge temperature 100 0C Rated output cooling air flow 14070 Nm3/h Max output cooling air flow 17980 Nm3/h Conveyor belt type Bidirectional spiral Belt speed (normal/max) 70/140 mm/s Service life of the chain and chain wheel 30000 h Service life of mesh belt 50000 h Slag storage capacity 12 m3 Max amount of slag storage allowing start with load 12 m3 Chain tensioning mode Hydraulic automatic

Speed regulation mode variable frequency speed control

Signal that can be monitored and obtained in the control room

Slip, overload, chain rupture

Conveyor chain motor model QABP-160 Conveyor chains motor power 18.5 kW Conveyor chain reducer model SC6004 Cleaning chain motor model DM100 Cleaning chain motor power 2.2 kW Motor supply voltage 415 V IP IP55 Fire service installations Available Angle of inclined segment 27 Overall weight ~130 t

1.2.19 Slag crusher

Manufacture STATE GRID FUTONG Quantity 1 set/boiler Model 2PG800×1000 Rated output 52

53

1.2.16 Main technical parameters of slag conveying system

No. Parameter name Unit Design value

Guaranteed value Remarks

1 Effective volume of boiler slag pit m3 320 320 Actual volume 360 m3

2 Operating temperature of boiler slag pit 1000 1000 3 Closing time of slag discharge device h 6 6

4 Normal output of Dry slag conveyor (continuous) t/h 15~34.4 15~34.4

5 Maximum output of dry slag conveyor (continuous) t/h 51.4 51.4

6 Dry slag conveyor belt speed under normal output conditions m/min 0.8~8 0.8~8

7 Dry slag conveyor belt speed under max output conditions m/min 8 8

8 Dry slag conveyor cleaning chain speed under normal output conditions m/min 0.2~2 0.2~2

9 Dry slag conveyor outlet slag temperature under normal output conditions 100 100

10 Dry slag conveyor outlet slag temperature under max output conditions 100 100

11 Dry slag conveyor cooling air flow under normal output conditions m3/h 14070 14070

12 Dry slag conveyor cooling air flow under max output conditions m3/h 17980 17980

13 Surface temperature of dry slag conveyor equipment under normal output conditions

50 50

14 Effective width of dry slag conveyor belt mm 1400 1400

15 Upper metal plate material of dry slag conveyor belt

Heat-resistant stainless steel

Heat-resistant stainless steel

16 Upper metal plate thickness of dry slag conveyor belt mm 4 4

17 Dry slag conveyor tank width mm 1800 1800 18 Angle of inclination of dry slag conveyor 27 27 19 Temperature of air flow into the furnace 350 350

20 Particle size at the outlet of large slag crushing equipment mm 200 200

21 Slag crusher output t/h 52 52 22 Size of particle at outlet of slag crusher mm 30×30 30×30 23 Bucket elevator output t/h 60 60 24 Effective volume of slag storage bin m3 900 900 25 Filtration efficiency bag dust collector 99.9 99.5

26 Dust concentration of bag dust collector emission mg/m3 50 50

27 Biaxial agitating device output t/h 100 100 28 Vibrating feeder output t/h 100 100

System performance Value Unit

Normal operating conditions

Design output 15~34.4 t/h Cooled slag temperature 70 Cooling air flow 14070 Nm3/h

Max operating conditions

Design output 51.4 t/h Cooled slag temperature 70 Cooling air flow 17980 Nm3/h

52

Normal speed: m/s 0.04 Maximum speed: m/s 0.06 5 Cooling capacity and pressure Normal conditions: m3/h, MPa 8, normal pressure Maximum operating conditions: m3/h, MPa 20, normal pressure 6 Sealing form Anhydrous seal 7 Angle of inclination of the rising segment: ° 30 8 Tank volume m3 50 9 Motor Model: Power: kW 7.5 Voltage: V 415 Speed: r/min 1450 10 Driver: Manufacturer: Changzhou Nanjiang Reducer

Co., Ltd. Max torque generated: KNm 11767 Output speed range: rpm 11 11 Tensioning device: Manufacturer: Qingdao Jinhuahai Hydraulic

Manufacturing Co., Ltd. Tensioner oil pump model: CBN-E314 Tensioning cylinder stroke: mm 300 Cylinder diameter: mm 102 Max set pressure of the system: MPa 16 12 Material and thickness of the tank body Q235-A, 10

Wear-resistant material, thickness and service life of the tank body Basalt cast board, 40mm in thickness,

and service life of 8 years 13 Chain Chain specifications: φ26×92 Chain diameter: mm 26 Pitch: mm 92 Conveyor chain material and service life 14CrNiMo5 Manufacturer Tianjin Jinxin 14 Scraper Material and thickness of scraper mm Q235-A 65Mn Scraper width mm 182 Scraper material life hour 25000 15 Total weight: ton 38

1.2.15 High-concentration pump LV motor

Item Unit Data Model 1PQ83554PB90-Z Rated power kW 355 Rated voltage kV 415 Synchronous speed r/min 1500 Rated current A 690 Frequency Hz 50

Main characteristics

Efficiency % 96.4 Power factor 0.86 Stall torque (Times) 2.3 Stall current (Times) 7.2 Maximum torque Effi i

(Times) 2.9 Insulation class IP55 Weight kg 2100 Cooling method IC416 Direction of rotation Bidirectional

51

Size of connector with the coal mill (pipe dia./height/horizontal sextant angle): DN250/2.0m/35°;

Hopper wall thickness: 10 mm;

Hoppe wall material: Q235A;

Liner thickness: 16 mm;

Liner material: QT700-2;

Level meter model: EP-LA2600

1.2.11 Hydraulic jet pump of mill rejects

Quantity per boiler: 7sets;

Manufacture and design size:

Feed port: φ270mm;

Water inlet: φ75 mm;

Boosting nozzle: φ29 mm;

Discharge port: DN125 mm;

Solids carried per hour: 18000 kg/h (net output);

Velocity of mixture flow: 2.2 m/s;

Solids weight percentage: 20 %;

Water flow of nozzle:

Jet pump nozzle: 90 m3/h;

Booster nozzle: 90 m3/h;

Required water jet pressure: 0.9 MPa;

Main structure material:

Nozzle: MTCuMo-175;

Pump body: QT700-2;

Jet tube: QT700-2;

1.2.12 Conveying pipe

Pipe diameter: 159 mm;

Minimum wall thickness: 14 mm;

Medium velocity: 2.0 m/s;

Outer diameter × inner diameter: 159×131 mm;

Material: mixture of mill rejects and water;

1.2.13 High-pressure pump

Flow rate: 120 m3/h;

Head: 0.9 MPa;

1.2.14 Scrapper conveyor of mill rejects

No. Item Unit Parameter 1 Manufacturer

2 Type: Upper back chain water-immersed scrapper type

3 Conveying capacity Normal conveying capacity: m3/h 18.0 Max conveying capacity: m3/h 33.0 4 Chain pulling speed

50

Quantity 1 set

Tank diameter Ø12m

Tank wall thickness ≥10mm

Sewage treatment capacity >350m3/h

Effective volume ≥500m3

Sewage medium Overflow water of mill rejects conveyor, and sewage collected from bottom of tank

Sewage quality at inlet 300~2000mg/l (estimated)

Required drain water quality ≤300mg/l

Sewage suspended solids content at inlet: ≤2000mg/l (estimated)

Required suspended solids content in overflow water: ≤350 mg/l

Circulation nozzle quantity/diameter: 6pcs/φ8 mm

Flooding nozzle quantity/diameter: 3pcs/φ8 mm

Total water consumption of nozzle: 84m3/h (circulation nozzle: 54m3/h; flooding nozzle: 30m3/h)

Water supply required by nozzle: 0.4 MPa

Tank material: Q235-B

Total weight: 52 t

1.2.9 Surge tank

Quantity 1 set

Tank diameter Ø12m

Tank wall thickness ≥10mm

Sewage treatment capacity/set >350m3/h

Effective volume ≥500 m3

Sewage medium Drain water from clarified water tank, make-up water from hydraulic division

Sewage quality at inlet 350mg/l

Required drain water quality ≤120mg/l

Circulation nozzle quantity/ diameter: 6pcs/φ8 mm

Flooding nozzle quantity/diameter: 3 pcs/φ8 mm

Total water consumption of nozzle: 84 m3/h (circulation nozzle: 54m3/h; flooding nozzle: 30m3/h)

Water supply required by nozzle: 0.4 MPa

Tank wall thickness: 10 mm

Tank material: Q235-B

Total weight: 48 t

1.2.10 Mill rejects hopper

Quantity per boiler: 7 pcs;

Effective volume: 1.0 m3;

Mill rejects hopper dimensions: (L×W×H): 1340×1430×1440 mm;

Empty weight of each mill rejects hopper: 1.5 t;

All-up weight of each mill rejects hopper: 2.5 t;

Access door diameter: φ460 mm;

Water seal available or not: none;

49

1.2.2 Surge tank

Quantity 1 set

Hopper diameter Ø 15m

Wall thickness of hopper ≥10mm

Effective volume ≥750 m3

Sewage medium Overflow water of concentrator, and make-up water from hydraulic division

Sewage quality at inlet 350mg/l

Required drainage water quality ≤10 ppm

1.2.3 Distribution box

Quantity 1 set

Box size 6000X1500X1500 (L×W×H)

Effective volume ≥10 m3

Outlet (2 pieces) Ø630X11

Overflow port (2 pieces) Ø325X8

1.2.4 Agitating device

Quantity 4 sets

Diameter Ø750mm

1.2.5 Bottom slag hopper overflow water tank (each boiler)

Quantity 1 set

Tank diameter Ø 4m

Tank height 4.5m

Tank wall thickness ≥6mm

Effective volume ≥50 m3

Water inlet flange PN1.0, DN300

Water outlet flange PN1.0, DN250

1.2.6 Vacuum pump house water storage tank (each boiler)

Quantity 1 set

Tank size 2500X1500X1500 (L×W×H)

Effective volume ≥5 m3

Water inlet floating valve PN1.6, DN65

Water outlet flange PN1.0, DN100 (2 pieces)

1.2.7 Mill rejects amount

Capacity Item 1×600MW 6×600MW

Coal consumption

Design coal (t/h) 346 2076 Check coal (t/h) 386.5 2319

Mill rejects Design coal (t/h) 3.46 20.76 Check coal (t/h) 3.865 23.19

1.2.8 Clarified water tank

48

c) air preheater ash 5%; d) ESP ash 90%. The ash bulk density: bottom ash and fly ash is 650kg/Cum as

calculated by volume, bottom ash and fly ash is 1350 kg/Cum as calculated by strength, ESP/air

preheater/economizer ash hopper is 650kg/Cum as calculated by volume.

1.2 Equipment specifications of slag handling system

1.2.1 Concentrator

No. Name Unit Parameter Remarks 1 Model GNJ15.0TB 2 Quantity Set 2 3 Hopper diameter m 15 4 Sewage treatment capacity/set m3/h 900 5 Effective volume/set m3 900 6 Effective settling area/set m2 1600 7 Sewage suspended solids content at inlet ppm 2000 8 Required suspended solids content in overflow water ppm ≤10 9 Harrow body diameter m 0.219 10 Rotary harrow diameter m 9 11 Rotary harrow speed r/min 0.148 12 Lifting harrow height m 350 13 Allowable max particle size of slurry mm 50 14 Material of inclined plate PVC 15 Thickness of the inclined plate mm 3 16 Quantity of inclined plate Piece 1200 17 Vertical distance between inclined plates mm 90 18 Angle between inclined plate and horizontal plane 65° 19 Wall thickness of hopper mm 10 20 Drive motor model Y100L2-4 21 Main harrow motor power kW 3.0 22 Main harrow motor voltage V 415 23 Main harrow motor IP IP56 24 Drive mode of main harrow motor Direct connection 25 Reducer model XWED3-84-1/187 26 Reduction ratio 1:187 27 Lifting motor power kW 2.2 28 Lifting motor voltage V 415 29 Total weight of the whole unit/set t 100

Technical data of drive motor

Items Unit Data Model Y100L2-4 Rated power kW 3 Rated voltage kV 0.415 Synchronous speed r/min 1500 Start-up current A 56 Rated current A 6.8 Frequency Hz 50

Main Characteristics

Efficiency % 82.5 Power factor 0.81 Stall torque (Times) 2.2 Stall current (Times) 7.0 Maximum torque (Times) 2.2

Insulation class F Weight kg 55 Cooling method Air cooled

Direction of rotation Clockwise (viewed from drive end to non drive end )

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PART 3 Ash & Slag System

Chapter 1 System Overview

1.1 Overview of slag handling system

In this project, the boiler slag is handled by hydraulic conveying mode, i.e. the boiler slag is discharged into

the water sealing slag hopper for cooling, cooled bottom ash and slag are sent through the slag discharge

valve outlet to crusher for crushing, and then conveyed to the ash slurry pond by hydraulic jet pump. The

fly ash in economizer ash hopper is conveyed to the ash slurry pond by hydraulic jet pump. The ash and

slag discharged into the ash slurry pond are conveyed to the ash year through pipeline by the ash slurry

pump. Overflow water from the water sealing slag hopper is conveyed to the concentrator by overflow

water pump, and the clarified water overflows to the surge tank.

This project of 3X600MW coal-fired unit is set with one concentrator and one surge tank. The 6X600MW

coal-fired units of the whole plant are set with 2 concentrators and 2 surge tanks. The concentrator and

surge tank in common use by boilers # 1, #2 and #3 are arranged in between #1 and #2; the concentrator

and surge tank in common used by boilers # 4, #5 and #6 are arranged in between #5 and #6.

Each boiler is individually set with mill rejects conveying system which uses mill rejects hopper (provided

by coal mill manufacturer) and hydraulic jet pump to convey the mill rejects discharged from the mill to the

mill rejects scrapper’s upper hopper through pipeline, and then transported out by dumping truck. The

conveying water of mill rejects is overflow water of mill rejects conveyor that is treated in clarified water

tank and surge tank and provided by high pressure pump. Conveying sequence: mill rejects discharge outlet

→ mill rejects hopper feed valve → mill rejects hopper → mill rejects hopper discharge valve → hydraulic

jet pump→ mill rejects scraper’s upper hopper → truck. Each boiler is set with one mill rejects conveying

system which design conveying output could guarantee that the mill rejects generated in 4 hours of running

under MCR condition can be conveyed to the mill rejects scrapper’s hopper within 1 hour, and is not less

than 16t/h.

Mill rejects conveying system is hydraulic conveying, which forms one unit for each boiler that runs

intermittently. The mill rejects are conveyed by hydraulic jet pump through pipeline to the mill rejects

scraper’s upper hopper, and then transported out by dumping truck. The overflow water of mill rejects

scrapper is treated in the clarified water tank and surge tank and then provided by high-pressure pump to

the mill rejects conveying system. There is one clarified water tank and surge tank in common use by

3X600MW unit. 6X600MW unit is set with totally two sets of clarified water tank and surge tank.

Slag handling system is included in the PLC control system for monitoring, the whole system uses

automatic programmable control, with control point set in the ash handling control room, and the state of

which can be monitored in the centralized control room of unit plant. For ease of loading, slag bin

unloading uses local control mode, by which the loading is monitored directly locally. Except the slag

handling and conveying equipment that are designed for boiler BMCR condition with poorest coal quality,

all the other equipment from bottom slag hopper to the slag bin are designed by 150%. For each boiler, the

total ash content is designed at least the following percentages: a) bottom ash, 20%; b) economizer ash 5%;

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No. Fault Cause Solution

7

The system does not continue running after the solenoid seal valve is opened

Seal ring is damaged; Sealing pressure is lower than the sealing pressure switch settings;

1. Replace the seal ring; 2. Check whether the air source pressure is greater than 0.50Mpa; Check whether the sealing pressure switch setting is higher;

8

After rotation of the discharge valve, the system does not intake air for conveying

The discharge valve opens in place but the limit switch makes no signal, there are the following reasons: Position of limit switch is wrong The limit switch has been damaged;

1.Adjust the position of limit switch; 2. Replace the limit switch;

9 System plugging

Feeding time is too long; Conveying pressure is lower; Conveying air flow is too small; Air supply amount is too small;

1.Adjust the feeding time; 2. Adjust the regulated value of pressure relief valve on the air intake valve block; increase the conveying pressure; 3. Adjust the air intake orifice plate, and increase the air supply amount; 4. Adjust the orifice of flow orifice plate, and increase the air supply amount.

45

DN 200 dome valve maintenance guidance: DN200 dome valve is mounted on the transmitter for feeding.

Before maintenance for security considerations, please pay attention to the following matters:

1) Ensure the system is local control;

2) Close the maintenance valve (flapper valve);

3) Change the conveying cycle switch to the “Start” position, and runs conveyor for 2 cycles;

4) The dome valve is in the closed position;

5) Close the air intake valve; close the manual ball valve on the inlet valve block;

6) Carefully open the pressure relief valve to ensure no residual pressure in the system;

7) Turn off the manual air intake valve on the local control box;

8) Demount compressed air piping on the dome valve;

3.4 Fault diagnosis of ash conveying system

No. Fault Cause Solution

1

Manual access door cannot be tightly closed after it is opened

Valve is opened beyond limit

Loosen the bolts between connecting plate and valve flange, draw out the valve plate 100mm, and insert it at 15° tip back into place.

2 Feed valve does not rotate after air supply

1. Low pressure air source. 2. Pneumatic device air inlet blow-by 3. Valve spindle lubrication is not good

1. Adjust the pressure of air source 2. Maintain pneumatic device and bearing, and increase lubrication

3

The feed valve sealing pressure switch signal is unavailable.

Feed valve seal ring is damaged; Ball position misalignment; Seal ring does not inflate; Air source pressure falls below the seal switch setting; Pressure switch setting is over high

1. Replace the seal ring; 2. Adjust the pneumatic device to the extent that the pneumatic device is in the closed position when ball position is in the middle; 3. Check the air line, and check the solenoid valve for damage; 4. Adjust the pressure of air source; 5. Adjust the sealing pressure switch setting

4 Discharge valve does not operated after air supply

Low pressure gas source; The pneumatic device intake and exhaust ports blow-by; Gap between the valve body and the valve core is too small, with jamming

1. Adjust the pressure of air source; 2. Maintain the pneumatic device; 3. Adjust the gap between the valve body and valve core;

5

Conveying air pressure switch signal is active during the transmitter feeding

Intake valve does not close in place; Conveying air pressure switch value is lower

1. Maintain the air intake valve; 2. Adjust the conveying air pressure switch value;

6 The feed valve seal ring is replaced frequently

Feed valve is closed not in place, the air intake is sealed; Air intake misaligns with collar hole; Sealing pressure switch setting is low, less than 0.40Mpa; Sealing pressure switch setting is higher, more than 0.55Mpa

1. Adjust the feed valve closing time; 2. Adjust the position of air intake and collar hole, make them aligned; 3. Adjust the sealing pressure switch setting; 4. Adjust the setting of pressure relief valve of air source triplet

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equipped with a double-contact pressure in order to ensure the seal charging and relief pressure of seal ring

reaches the set pressure. The domed surface is smooth and hard, so that it can be brought into close contact

with rubber seal ring. The rubber seal rings are made of specially-formulated rubber, which are corrosion

resistant, wear resistant, and anti-aging. The actuator of the valve is fully sealed bidirectional straight

cylinder, which directly drives the feed valve to rotate, effectively preventing dust from entering wherein

and causing wear, leakage and other problems. The dome valve is provided with a mechanical control valve

at the output of rotating shaft, which connect through the sealing air passage when the dome valve operates

in place.

Structural diagram:

Working principle: before the dome opening and closing, the seal ring first release pressure, when the

pressure reaches the low value set for pressure switch, it indicates the seal ring is completely separated

from the dome, with a gap between about 2 ~ 3mm, when the valve is closed in place, the seal ring starts to

inflate until the pressure reaches the high value set, seal ring clings to the dome, forming a very reliable

seal valve ring band. In the switching process, the dome does not contact with the seal, and thus the

opening and closing moment is small, while the sealing surface of the dome and the seal ring of valve body

are not easily damaged.

Main technical parameters

Nominal Diameter DN200 Air bag design pressure 0.6 MPa Feed valve design pressure ≤0.5MPa

Control air source Pressure 0.55~0.6 MPa Air consumption 1L/time

Cylinder Cylinder DN125 Actuator output torque 650N·m Operating Temperature ≤170 Design temperature 200 Suitable medium Fly ash, limestone powder, etc.

43

7. Temperature sensor failure Check and replace the temperature sensor

Low exhaust pressure

1. Air demand exceeds supply Detect pipeline for leakage 2. 2. Air filter is blocked Clean or replace the filter element 3. Intake valve can not be fully opened Check the air intake

4. Oil-gas separator element is blocked

Check the pressure gauges and display values before and after the oil-gas separator element, if necessary, replace the oil separator element.

Unloading failure 1. Air intake valve failure Check the air intake valve 2. Pressure sensor failure Repair, if necessary, replace

Frequent loading and unloading

1. Piping leaks Check piping 2. Differential pressure between loading and unloading is set too small Reset

3. Unstable air consumption Increase the air storage tank volume

The oil content in air is too high, oil

consumption is too high

1. The amount of oil is too high Check the oil level, and discharge oil to its normal position

2. Return pipe orifice blockage Clean the oil return pipe orifice and replace it if necessary

3. Oil-gas separator element or gasket is damaged

Check the filter element and gasket, replace if damaged

4. Exhaust pressure is too low. Increase the exhaust pressure Ultra-high pressure

Actual pressure is ultra-high, and sensor is not accurate

Check machine pressure and the pressure sensor

Lack of phase Power phase failure, contactor contact is bad, etc. Check the power and contactor

Overload Too low voltage, pipe blockage, bearing wear, other mechanical failure, set data error

Check the setting data, check the voltage, bearings, piping and other mechanical failure

Unbalance Power imbalance, bad contactor contacts, inside of motor has open loop, etc.

Check the power supply, contactor and motor

Stall Low voltage, pipe blockage, bearing wear, other mechanical failure, sett data error

Check the set data, check the voltage, bearings, piping and other mechanical failure

Short circuit Wiring error, set data error, etc. Check the line, setting data Phase sequence

error Phase sequence is reversed, phase failure Check the line

Fan is not running Fan failure, contactor failure, no control output Check the line

Main unit overload, stall, etc. electrical fault in

the starting process

The main unit startup time is set to be less than the star-delta delay time

Reset the start time of main unit to be more than star-delta delay + load delay

Regular action of the main contactor Emergency stop button becomes loose Check the wiring

3.3 Other equipment structure and maintenance

3.3.1 Dome valve

Pneumatic dome valve is special valve for conveying powder material, the feed valve as transmitter in the

present system and the discharge valve in each electric field. The dome valve body is constituted by ductile

iron. The valve core is dome-shaped and made of stainless steel, with surface hardening treatment. Valve

core rotates 90°by the rotating shaft on both sides, to open and close the valve. Valve is equipped with a

pneumatic seal ring on the upper portion close to the dome top, the pneumatic piping of seal ring is

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E. too large running current of compressor result in the thermal overload fault indicator lights up

1. Thermal load is too large and the intake air temperature is too high 2. The ambient temperature is too high. 3. Insufficient refrigerant results in too high degree of its superheat 4. Compression overload 5. Compressor lacks of oil or oil level is too low 6. Compressor bearing is worn or cylinder is jammed

1. Reduce the thermal load and the intake air temperature 2. Improve ventilation conditions to reduce the ambient temperature. 3. Add refrigerant 4. Reduce the number of compressor start 5 Check compressor oil level, and add oil 6. Replace compressor

F. Evaporator internal icing, appearing as the drainer failure to drain water, and ice particles blowing out after opening the blowdown valve

1. Air flow is too small or the load is too light 2. Hot gas bypass valve is not open or poor and expansion valve opens too large 3. Evaporator drain outlet is blocked, too much water deposit creates ice block

1. Increase the compressed air flow or load 2. Adjust or replace the hot gas bypass valve and expansion valve 3. Dredge drain port to discharge the evaporator condensate

G. Equipment is operating normally, but the pressure drops significantly

1. Low air intake pressure. 2. Pipeline valve is not fully opened 3. Pipe diameter is too small, the elbow too many or piping is too long 4. Evaporator ice blockage 5. Compressor suction filter is blocked 6. Equipment has too much water deposit 7. Selected equipment has a lower treatment capacity 8. The air system is blocked by dust

1. Increase the intake air pressure 2. Open all air line valves 3. Improve air piping system 4. Refer to F1-3 5. Clean or replace the filter 6. Check repair or replace the drainage system 7. Increase equipment or replace the equipment of greater treatment capacity 8. Reversely clean with cleaning agent

H. Equipment operation noise is too high

1. Fan blades are bent 2. Fan motor bearing is worn 3. Refrigerant liquid return 4. Compressor is damaged (cylinder jamming, bearing wear) 5. Compressor lacks of oil

1. Make correction or replace 2. Replace fan 3. Check adjust or replace expansion valve 4. Replace compressor 5. Check the oil level, add oil and check whether the oil heater is working properly

I. Liquid piping frosting

1. Valves on high-pressure side are blocked 2. Dry filter is blocked

1. Open the valve to remove blockage 2. Replace

J. Suction pipe frosting

1. Expansion valve is abnormal 2. Hot gas bypass valve is not opened or poor

1. Replace the expansion valve 2. Adjust or replace the hot gas bypass valve

3.2 Fault analysis and solution of air compressor

Fault Possible Cause Solution

Start failure

1. Fuse blew out Please contact with the electrical personnel for maintenance or replacement

2. Protection relay operates 3. Poor contact of start button 4. Voltage is too low 5. Motor failure

Exhaust temperature is too

high

1. The ambient temperature is too high. Improve ventilation around 2. Thermostatic valve failure Check and replace the thermostatic valve 3. Insufficient amount of lubricating oil. Check and adjust oil level 4. Oil cooler fins are too dirty Clean cooler fins 5. Oil filter is blocked Replace the oil filter 6. Cooling fan failure Replace the cooling fan

41

Chapter 3 Routine Maintenance & Treatment

3.1 Typical fault analysis and treatment of refrigeration dryer

The main fault of refrigeration dryer comes from the circuit and cooling systems, and the final result will

inevitably lead to failure to start of the compressor, cooling capacity reduction or equipment damage.

Making correctly judgement of the causes of various faults and taking reasonable solutions not only involve

the theoretical knowledge of electrical and refrigeration technology, but what is more importantly is having

practical skills, some faults may be caused by several reasons, you must first of all make comprehensive

analysis of the fault phenomenon to find an effective solution. In addition, some faults are often caused by

improper use and maintenance by the user, and that is so-called “pseudo-fault”, so the location of fault can

only be determined through actual operation so as to find the right solution. The refrigeration dryer’s some

common faults and solutions are highlighted as follows:

Fault phenomenon Cause Analysis Solution

A. Refrigeration dryer does not work

1. No power supply 2. blown fuse 3. Circuit is open or loose

1. Check the power supply system 2. Replace the fuse 3. Check the line according to the circuit diagram

B. Compressor does not run

1. Power phase failure or voltage is outside the allowable range 2. Incorrect wiring 3. Relay or contactor does not pick up 4. If the compressor is capacitor start, then the start capacitor may be damaged 5. HV and LV protection switches are poor 6. Compressor mechanical failure, such as cylinder jamming

1. Check the power supply to make supply voltage be within the nominal range 2. Check line according to the circuit diagram 3. Check the reason, replace or repair 4. Replace start capacitor 5. Adjust the pressure switch setting, or replace the pressure protection switch 6. Replace compressor

C. Too high pressure of refrigerant results in the high refrigerant pressure fault indicator lights up

1. Thermal load is too large and the intake air temperature is too high 2. Ambient temperature is too high. 3. Condenser is dirty and blocked or cooling water is insufficient and cooling water temperature is too high 4. Air mixed in the cooling system 5. Fan rotation direction is incorrect or fan motor failure 6. Expansion valve is abnormal 7. Dry filter is blocked. 8. Refrigerant charge amount is too large

1. Reduce the thermal load and the air intake temperature 2. Improve ventilation conditions, and reduce the ambient temperature. 3. Clean condenser or increase the amount of cooling water and reduce the temperature of cooling water inlet 4. Find out the reasons and maintain. 5. Exchange any two of the three phase lines or replace fan 6. Replace the expansion valve 7. Replace 8. Discharge refrigerant (the above reasons must be excluded before this operation)

D. Too low pressure of refrigerant results in the refrigerant pressure fault indicator lights up

1. Refrigerant shortage or leakage 2. Air flow is too small or load is too light 3. Hot gas bypass valve is not open or poor 4. The ambient temperature is too low.

1. Make leak detection, extract vacuum once again and charge refrigerant 2. Increase the compressed air flow or load 3. Adjust or replace the hot gas bypass valve 4. Reduce the cooling water flow, or turn off the cooling water

40

When the system runs under automatic control of PLC control system, each boiler creates a conveying unit.

Its basic operating steps are as follows:

System feed. The exhaust valve is opened, then the seal ring of feed valve is released from pressure, and

feed valve is opened, when any a vessel transporter in the conveying system reaches the set material level

(or reaches the clock setting), the system is triggered.

Conveying. Close the core of feed dome valve is closed, pressurize the seal ring for sealing, and confirm

normal closing by the pressure switch, and close the exhaust valve, open the discharge valve, and in the

meanwhile open the air intake valve block and gulp valve, opens the boost air intake valve block, then the

compressed air will convey the ash to silo ash from all the conveyors.

System reset. There is pressure switch on the air intake line, as reaching the set low limit, close the

compressed air inlet valve block and boost air intake valve block, and then close the discharge valve,

system resets, and waits for the next cycle.

2.10.3 Programmed logic

2.10.3.1 Starting point

Feed valve (dome valve) is closed.

The conveying pressure is zero.

Discharge valve closed.

The sealing pressure is zero.

2.10.3.2 Feed

Open the exhaust

Wait 3 seconds, and then close the feed valve for sealing.

Wait 5 seconds, and then open the feed valve for feeding.

2.10.3.2 Feed valve is closed

Level meter operates or feed time out, close the feed valve and exhaust valve

5 seconds later, open the inlet valve seal.

When the sealing pressure reaches 5.5 bar, the feed valve is opened.

2.10.3.3 Conveying

When the discharge valve is fully open, the air intake discharge is opened.

Once pressure is set up in the transmitter, and the fly ash moves in the pipeline.

The conveying process continues until the conveying pressure is reduced to the set value, and lasts the

shortest conveying time.

The conveying compressed air is discharged from the bag dust collector.

2.10.3.4 Conveying process end

The conveying pressure is zero.

Air intake and discharge valve are closed.

Discharge valve is closed.

Transmitter waits for a new start signal from the material level meter.

39

2.8.2 For the water-cooled type, the cooling water inlet and outlet valves should be opened;

2.8.3 Press the green start button, contactor picks up until the start indicator (green) lights up, 5 minutes

later when the start indicator (green) goes out, the compressor starts running, with running indicator (green)

lit up;

2.8.4 Check whether the compressor is functioning properly, with or without abnormal noise, whether the

pointer of refrigerant LP gauge dropped to within the normal range of 0.3 ~ 0.5MPa (R22 refrigerant).

2.8.5 If everything is normal, turn on the air compressor and the air inlet and outlet shutoff valves to supply

air to the refrigeration dryer, and close the air bypass valve, at this point, the air pressure gauge will

indicate the pressure of the air outlet;

2.8.6 After 5 ~ 10min of observation, the air temperature treated by the refrigeration dryer can reach up to

the design pressure dew point 2~ 10 , at this point, the refrigerant HP and LP gauge indicate normal range

as follows:

Refrigerant low voltage: R22 R407C 0.3 ~ 0.5MPa R134A 0.1 ~ 0.3Mpa

Refrigerant pressure: R22 and R407C 1.2 ~ 1.8MPa R134A 0.7 ~ 1.1Mpa

2.8.7 Slowly open the copper ball valve of automatic drainer, so that the condensate in the air flows into the

drainer to be discharged thereby.

2.9 Shutdown process of refrigeration dryer:

2.9.1 Open the bypass valve to allow compressed air to continue to flow into the downstream pipeline, and

then close the outlet valve of refrigeration dryer;

2.9.2 Close the inlet stop valve of refrigeration dryer, and release the pressure of refrigeration dryer;

2.9.3 Press the red stop button to stop the refrigeration dryer, and cut off the power, open the hand-operated

blowdown valve to discharge all the residual condensate.

Operation of the refrigeration dryer should pay attention to that: 1. Try to avoid the refrigeration dryer

operating with no load for long; 2. Prohibit the refrigeration dryer to start and stop within a short time, the

interval should be at least 10 minutes so as to avoid damage to the refrigeration compressor.

2.10 Operation and control of pneumatic ash conveying system

2.10.1 Control mode

The control system uses three control modes: full automatic control, remote hand operation and local

control.

Under normal circumstances, the system uses full automatic control mode. In the full automatic control

mode, the operator sends starting or stopping commands to the ash conveying system via the computer

keyboard installed in the control room, the whole ash conveying system will run based on the process

professional requirements in order. If the system is running conditions are not met, or the selected device

has fault, the cause of fault will be displayed on the CRT.

In remote hand operation mode, the operator sends commands to equipment of ash conveying system via

the computer keyboard installed in the control room, the interlock mode between equipment is the same

with that in the full automatic control mode.

Local control mode: in maintenance of equipment or commissioning, the equipment operation is controlled

manually with the local control box.

2.10.2 Operation mode

38

The tip “*” on upper right corner indicates entering the user parameters setting status.

Press the Shift key “ ”, there will be a flicker bit, then press the key “ ” and “ ” to change the

flicker bit, after that, press the Shift key to move the flicker bit to the next one, press the key “ ” and

“ ” to change the flicker bit, after editing all the bits in this way, press the confirm key “S” to save data.

It may edit other user parameters in the same way.

2.6 Routine inspection of air compressor

Period Operation Every day Check the oil level. ″ Check the reading of display screen. 3 months Check the cooler, and clean up if necessary ″ Remove the air filter element, clean up with compressed air and check.

If the compressor is running in a dusty environment, clean up more frequently. If the air filter element is damaged or contaminated seriously, please replace the air filter element.

″ Check whether all electrical components are operating normally, and tighten the terminals of the main power supply.

The condensate in air may accumulate in the tank, particularly in wet weather, when the exhaust

temperature is below the pressure dew point of gas or shutdown for cooling, there will be more condensate

precipitated. Oil containing too much water will cause oil emulsification, affecting the safe operation of

machine; therefore, condensate should be discharged depending on humidity on a regular basis. The

condensate should be discharged after the machine shut down and cooled sufficiently, and the condensate is

precipitated sufficiently, such as before startup in the morning.

2.7 Inspection before startup of series refrigeration dryer

2.7.1 Check the cooling system: observe the readings of HP and LP gauge on the instrument panel of

equipment, which should reach a balance under a certain pressure, while this equilibrium pressure

fluctuates with the ambient temperature, generally around (0.5MPa~1.2MPa).

2.7.2 Check whether the power supply voltage is normal, (AC220V/50HZ ± 5% for

SLAD-0.5NF~SLAD-8.5NF; 3-phase AC380/220V/50HZ ± 5% for above SLAD-10NF).

2.7.3 Check whether the air line is normal, the air inlet pressure must not exceed the working pressure in

selection, and the intake air temperature should not exceed that determined in selection as much as

possible.

2.7.4. Refrigeration dryers with handling capacity of 30 cubic meters and above are equipped with a

compressor oil heater that must be warmed up for more than 8 hours before the equipment is started for the

first time (with power on, the heater automatically heats), to ensure that the oil temperature in compressor

oil chamber is at least higher than the ambient temperature by 10 , otherwise, the compressor will be

seriously damaged.

2.7.5 If water cooling mode is selected, you should also check whether the cooling water has been

connected to the condenser, cooling water is normal, water pressure is 0.2Mpa~0.4Mpa and water

temperature is ≤ 32 .

2.8 Starting process of refrigeration dryer:

2.8.1 Power on, close the air switch, and the power indicator (red) on the equipment instrument lights up.

37

2.5.2.2.1 Viewing operating parameters

Press “ ”to view the operating parameters directly: first pressing it to view the total operating time

Press “ ” in order to view the status of the following parameters:

Load running time, main motor current, fan current, current running time, current load time, load/unload

pressure, historical fault 1, historical fault 2, historical fault 3, historical fault 4, historical fault 5, date of

manufacture, factory ID, user parameters, manufacturer’s parameters, etc.

2.5.2.2.2 Viewing and editing user parameters

1) Parameter editing method

User parameters and manufacturer’s parameters can not be edited in the running state and

shutdown delay process.

It can view and edit the user parameters by aforementioned means of viewing operating parameters, such as

edit the upper pressure limit, the operating method of which is as follows:

Press the Move upward key “ ” or Move downward key “ ” to move the black scroll bar to the

display the following screen

Then press the Enter key, the following screen will pop out:

Again press the “ ” key to pop out the following screen on which it is required to input password:

Note: the password can be edited in the User parameters

After this screen pops out, there will a flicker bit, at this point the keys “ ” and “ ” become

Increase and Decrease key, used for editing the data on current flicker bit, the key “ ” becomes Shift

key to move the flicker bit, at last, press the confirm key “S” to confirm input. After the system validates

correct password, the following screen will pop out:

Total operating time: ****hour****minute

User Parameter Mfr. Parameter

Low pressure limit

00.50MPa

Input password: ****

Low pressure limit

00.50MPa

36

ON - Start button: press this button to start the motor running.

OFF - Stop button: press this button to stop the motor running

S - Confirm key/Load & Unload key: confirm the input after editing data; acts as the load and unload key

when the air compressor is running.

- Move upward/Increase key: press this key to increase the current position data; to move the the last

menu as selecting menu.

- Move downward/Decrease key: press this key to decrease the current position data; to move to the

next menu as selecting menu.

- Shift/Enter key: press this key to shift position as editing data; acts as the enter key as selecting

menu.

- Return/Reset key: press this key to return to the last stage of menu in menu operation; press this key

to reset as shutdown for fault.

2.5.2 2 Status display and operation

The unit displays the following screen after powered on:

The following main screen is displayed 5 seconds later

Press the Move Leftward key “ ” to view the exhaust temperature:

Welcome to use Screw

Compressor

Tep.: 10 Pressure: 00.00 Status: OFF

Tep.: 10 Pressure: 00.00 Status: OFF

35

Chapter 2 Pneumatic Ash Conveying Operation 2.1 Preparations before air compressor starting

2.1.1 Check whether all the mechanical components and piping of air compressor are in reliable connection,

if any loosening, give treatment timely.

2.1.2 Check the compressor oil level, when the oil level is higher than the lowest position on the fuel gauge,

the unit can be started for normal operation, and even if the oil level at once cannot be seen after the unit

starts running, it will not affect the normal use of the unit.

2.1.3 Turn the coupling manually following the required direction for several rounds to ensure that the unit

rotates flexibly.

2.1.4 Check whether the electrical part is in compliance with the requirements of safety regulations, and

switch on the power after confirming it.

2.2 Air compressor start

2.2.1 The following procedures should be followed when the air compressor is started initially or restarted

after the air compressor and its system equipment maintenance:

a. Check whether all the valves are in the right position and the right open or close state;

b. Remove all the maintenance attachments for security maintenance (such as the blind plate), and signs for

maintenance;

c. Check the system and remove the foreign matters inside;

d. Open and then close the drain valve again;

e. Turn gear for at least a round to ensure that no mechanical interference;

2.2.2 If there is no phase sequence error displayed on the unit control screen after power on, then it can

press the “Start” button for normal starting, please verify the correct direction of rotation of the drive motor

and rotating equipment after startup, and make sure all the safety devices are in proper operating status.

2.2.3 After unit startup process is completed, the air compressor enters the state of automatic control.

2.3 Air compressor running

2.3.1 After the operation of unit becomes normal, check throughout the unit for oil or air leakage, if any

shut down for treatment immediately.

2.3.2 Check whether the exhaust pressure, exhaust temperature and other operating parameters are normal.

2.3.3 Make good job of running records, compare whether various operating parameters are always normal,

if there is an abnormal phenomenon, it should promptly shut down and make analysis to find the cause.

2.4 Air compressor shutdown

2.4.1 If it is necessary to stop the running unit, then it only needs press the stop button, the unit will shut

down 20-30s after compressor automatically unloads. Do not use the emergency stop button to stop the unit

if there is no particular reason.

2.4.2 Cut off power of the unit.

2.5 Air compressor computer controller

2.5.1 Description of keys

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No. Name Unit Hangzhou Shanli 1 Model SLAD-70NW-ZF 2 Type Fin type 3 Overall dimension mm Φ466X1644 4 Cooling area m2 85 5 Compressed air inlet & outlet temperature 30/5 6 Copper tube material T2 7 Weight kg 180

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Working pressure: 0.6-1.0MPa;

Working temperature: 0-50 ;

Filter element material: Fiberglass;

Filter precision: 1μm;

DOP efficiency: >99.96%;

Service life of filter element: >8760h;

Filter differential pressure: 7kPa;

Weight: 115kg.

22.3 Main technical data of gas-liquid separator

No. Name Unit Hangzhou Shanli 1 Model SLAD-70NW-GF 2 Treatment medium Air 3 Rated air capacity processed Nm3/min 69 4 Separation principle Stainless steel screen 5 Working pressure MPa 0.85 6 Pressure loss MPa 0.001 7 Dehydration efficiency % 99 8 Model of automatic blowdown valve RPT-16 9 Discharge interval min 0.5 10 Discharge time each s 5 11 Case material Q235B 12 Capacity L 130 13 Weight Kg 80

22.4 Main technical data of pre-cooler

No. Name Unit Hangzhou Shanli 1 Model SLAD-70NW-YL 2 Type Light pipe type 3 Overall dimension mm Φ412X2074 4 Cooling area m2 15 5 Velocity of pipe side medium m/s 8 6 Velocity of case side medium m/s 7 7 Exhaust port temperature 30 8 Suction inlet temperature 45 9 Case material Q235B 10 Weight kg 320

22.5 Main technical data of condenser

No. Name Unit Hangzhou Shanli 1 Model FS15S6 2 Type Shell-tube type 3 Overall dimension mm Φ168X1354 4 Cooling area m2 7.8 5 Velocity of pipe side medium m/s 1.5 6 Velocity of case side medium m/s 0.5 7 Copper tube material T2 8 Weight kg 68

22.6 Main technical data of evaporator

No. Name Unit Hangzhou Shanli

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No. Name Unit Technical parameter Remarks 1 Air capacity Nm3/min 69 2 Intake pressure MPa 0.1013 3 Ambient temperature -5~50 4 Discharge pressure MPa 0.8 5 Cooling water amount (water pressure) MPa 0.2~0.6

Cooling water amount (water volume) m3/h 18~51 6 Discharge temperature <40 7 Shaft power kW 391 8 Specific power Nm3/kW 5.7 9 Positive and negative rotor shaped wire SAP shaped wire 10 Oil content of gas outlet PPm <3 11 Main motor model Y2-HV450-4 12 Nominal power of main motor kW 355 13 Service factor 1.2 14 Power supply 11KV/50HZ 15 Insulation class of main motor IP54 16 Protection class of main motor F 17 Unit noise dB(A) 82±2 18 Unit vibration μm 7.1 19 Unit overall dimension (length × width × height) mm 4250×1900×2200 20 Unit weight kg 7390

22. Refrigerated compressed air drier

Quantity: 24sets;

Air capacity processed: 70Nm3/min;

Intake pressure: 0.6-1.0 MPa;

Intake temperature: ≤45 ;

Pressure dew point: ≤ 3 ;

Refrigerant: R22;

Pressure loss: <0.02MPa;

Cooling mode: Water cooled.

22.1 Pre filter

Model: SLAF-70HC;

Rated air capacity processed: 70Nm3/min;

Working pressure: 0.8Mpa (G);

Working temperature: 0-80 ;

Filter element material: stainless steel netting and fiberglass;

Water diversion efficiency: 99.9%;

Filter precision: 3μm;

Filter differential pressure: 7KPa;

Service life of filter element: ≥ 8760hr;

Weight: 115kg.

22.2 Dust removal filter

Model: SLAD-70HT;

Rated air capacity processed: 70Nm3/min;

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e) Chloride (Cl ): <150 mg/L.

21.3 Technical data of air compressor motor

No. Name Motor

1 Insulation class/Insulation treatment F/VPI (Vacuum Pressure Impregnation)

2 Operation factor S1 3 Temperature rise during operation at full load (resistivity method) ( ) 80K 4 Case/ Ventilation type IC411 5 Case protection degree IP54 6 Type of driving shaft Clutch driving 7 Model of built-in bearing 6328C3/6328C3

8 Rotating direction Clockwise (can be bidirectional)

9 Size of junction box (mm) 535×770 10 Voltage/Power/Quantity of heater (V/W) 240/2×250 11 Full load current/ Full load current multiple 25.8/7.0 12 Startup torque under rated voltage/min. startup voltage (multiple) 11/0.512 13 At full load 93.4/0.85

At 3/4 load 94.0/0.82 At 1/2 load 93.0/0.78

14 Model and specification of recommended lubrication Caltex SRI-2 15 Rotor material Cu (copper cage) 16 Type and model of stator RTD PT100 17 Type and model of bearing RTD PT100 18 Sound pressure level (1 meter away from motor case) dB(A) 94 19 Model/Code of manufactory base H450 20 Overall dimension/Chart no. (mm) 2169×1416×1084/OG45001969 21 Weight (kg) 3700 22 Manufactory name Huada

21.4 Summary statement of air compressor performance parameters No. Name Unit Technical parameter Remarks

Item Unit Data Model Y2-HV450-4 Rated power kW 355 Rated voltage kV 11 Synchronous speed r/min 1500 Startup current A 180.6 Rated current A 25.8 Frequency Hz 50

Primary properties

Efficiency 93.4 Power factor 0.85 Stall torque 0.8 Stall current 7.0 Max. torque 2.0

Insulation class IP54 Weight kg 3700 Cooling mode IC411 Rotating direction Clockwise (viewed from drive end to non drive end)

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Item Unit Data Model Y2 315L1-4 Rated power kW 160 Rated voltage kV 0.415 Synchronous speed r/min 1500 Startup current A 1531.5 Rated current A 263.2 Frequency Hz 50

Primary properties

Efficiency % 94.9 Power factor 0.89 Stall torque (Times) 2.2 Stall current (Times) 5.81 Max. torque (Times) 205% of the max load

Insulation class F Weight kg ~1150 Cooling mode Air cooling Rotating direction Clockwise (viewed from drive end to motor)

21. Air compressor

21.1 Main technical specifications of the equipment

Model: BLT475W.

Type: screw type, low noise, and micro-oil type air compressor.

Installation quantity: 24sets.

Rated output of air compressor: 69 Nm3/min (101.3KPa (absolute), 20 air as the standard air).

Rated working pressure: 0.8MPa.

Cooling mode: Water cooling.

Max. ambient temperature: 50 .

Outdoor air suction:

Oil content of air compressor outlet air: <3mg/m3.

21.2 Technical parameters for compressor

Product model Overall

dimensions Equipment

weight Dia. of equipment

exhaust port Dia. of cable

inlet Cable dia.

Cooling water amount

Vent. volume

L×W×H (mm) kg G/DN mm mm2 m3/h m3/h BLT-475W

(Water-cooled) 4250×1900×2200 7390 DN125 D120/D80 - 25–35 15000

Requirements of cooling water for water-cooling air compressor

Cooling water pressure is usually controlled within the range of 0.3-0.4MPa, and inlet & outlet water

pressure should be above 0.15MPa. Cooling water temperature should be controlled below 35 and inlet

& outlet water temperature should be around 10 .

Water quality requirement on cooling water:

a) PH value: 6.8<pH<8.

b) Total dissolved solids: <450mg/L.

c) Total hardness (uses CaCO3) <300mg/L.

d) Suspended matter: <50 mg/L.

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Vacuum relief value (Normal value/Max. value): 0.83x10-3MPa;

Weight: 512kg;

19. Primary technical data for fly ash handling system (Below is the data for single boiler)

System output: No less than200 (with negative pressure /No less than 240(with positive pressure)t/h;

Ash/Air ratio:

Negative pressure conveying: 15.17Kg/kg (average);

Positive pressure conveying: 19.24Kg/Kg (average);

Air consumption:

Average air consumption for unit conveying: 120m3/min;

Max. air consumption for unit conveying: 208m3/min (per boiler with positive pressure conveying);

Air consumption for unit instrument: 3m3/min;

Air consumption for each filter/separator bag cleaning: 1.5m3/min;

Power for system operation:

Average power: 704kW;

Peak power: 1232kW;

Power consumption for ash conveying of each ton: 6.16kWh/t;

Speed:

Negative pressure conveying part:

Initial velocity of fly ash conveying pipe: 24.13m/s;

End velocity of fly ash conveying pipe: 27.19m/s;

Positive pressure conveying part:

Initial velocity of fly ash conveying pipe: 6m/s;

End velocity of fly ash conveying pipe: 15m/s;

20. Vacuum pump

This project is Subcritical Coal-fired Power Plant Unit 6X600MW. And each unit is equipped with one

vacuum pump house for ash handling in each of which eight vacuum pumps are set. And there are totally

48 vacuum pumps in unit 6X600 with continuous and intermittent operation mode respectively.

Type of vacuum pump: liquid ring vacuum pump;

Model of vacuum pump: 2BE4 400-2BY3;

Inlet water temperature of cooling water: 33 (Normal), 36 (Max.).

Inlet water pressure of cooling water: 0.2~0.6Mpa.

Pumping capacity: 62.53kg/ min;

Suction pressure: -45.06 kPa;

Rotating speed: 495 r/min;

Efficiency: 47.75%;

Shaft power (Design point): 125.4KW;

Cooling mode (Air/Water): Air IC411;

Water consumption: 7.5m3/h;

Technical data of motor

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Design pressure: 1.0MPa;

Design temperature: 180 ;

Nominal diameter: 200mm;

Service life of vulnerable part: 8760h;

Fittings: Pneumatic triplet/Electromagnetic valve;

Weight: 260kg;

15. Exhaust valve of Fly ash conveying device

Manufactory: United Energy Group Limited;

Model: DN150;

Type: Double gate valve;

Quantity: 48sets;

Design pressure: 1.0MPa;

Design temperature: 180 ;

Nominal diameter: 150mm;

Service life of vulnerable part: 8760h;

Fittings: Pneumatic triplet/Solenoid valve;

Weight: 180kg;

16. Vacuum breaker

Type: ZKF;

Quantity: 24sets;

Property parameters: -75KPa/-100 KPa;

Overall dimension: φ275x308;

Interface size: DN150;

Air consumption of cylinder: 0.1 m3/min;

Weight: 16 kg;

17. Pressure vacuum relief valve (for ash silo)

Manufactory: Shanghai Zhongfen Electrics;

Model: SFF508;

Type: Bob-weight;

Quantity: 4sets;

Pressure relief value (Normal value/Max. value): 2.58x10-3MPa;

Vacuum relief value (Normal value/Max. value): 0.86x10-3MPa;

Weight: 126kg;

18. Pressure vacuum relief valve (for surge bunker)

Manufactory: UCC India;

Model:

Type: Bob-weight;

Quantity: 24sets;

Pressure relief value (Normal value/Max. value): 2.5x10-3MPa;

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11. Screw conveyor No. Name Parameter Unit Remarks 1 Equipment model LCS type 2 Lifting capacity 210 t/h 3 Blade 16Mn 4 Distance between center of inlet & outlet 11 m 5 Motor parameter

Motor model Y180L-4 Motor power 22 kW Motor rotating speed 1470 rpm Power voltage 415 V Motor insulation class F Motor protection degree IP55 Motor connection mode ‘’Y’’

12. Filter/separator

Type & Model: 126W72;

Quantity: 24sets;

Manufacturer: UCC India;

Air filtering volume: 117.8m3/min;

Filtering area: 101m2;

Filter efficiency: > 99% (by weight);

Pulse blowing air amount: 1.5m3/min;

Pulse blowing air pressure: 0.55 - 0.7MPa;

Filter overall dimension: Φ2.8 X10.4m;

Filter weight: 8074kg (without load)/18396kg (at full load);

Number & size of bag: 126bags/φ143X1835mm;

Air/cloth ratio of bag: <1.21m3/min/m2;

Filtering resistance: 1.69Kpa;

Filtering speed: 1.17 m/min;

Working temperature: 170 (MAX);

Service life: 8760h;

Total weight: 8074kg (without load)/18396kg (at full load);

13. Fluidizing slide of pneumatic conveying device

Manufactory: Shanghai Zhongfen Electrics.

Model: QHPZ150;

Type: Nozzle gasifying/fluidizing plate;

Quantity: 48sets;

Weight: 5kg;

14. Inlet valve of pneumatic conveying device (inlet & outlet valve)

Manufactory: United Energy Group Limited;

Model: DN200/DN300;

Type: Dome valve/Double gate valve;

Quantity: 48/48 sets;

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9. Electrical feeder

No. Name Parameter Unit Remarks 1 Equipment model DS200

Equipment output 200 t/h Specifications of inlet & outlet flange 600X600

2 Motor parameters Motor model Y132S-4 Motor shaft output 4.78 kW Motor power 5.5 kW Motor rotating speed 1440 rpm Power voltage 415 V Motor insulation class F Motor protection degree IP55 Motor connection mode ‘’Y’’

3 Noise 85 dB(A) 4 Weight 638 kg

10. Twin shaft mixer of ash unloading system for ash silo

No. Name Parameter Unit Remarks 1 Equipment model SZ200D 2 Equipment quantity 2 set 3 Equipment output 200 t/h 4 Max. output of equipment 200 t/h 5 Min. output of equipment 200 t/h 6 Equipment length 4.49 m 7 Moisture content of wet ash 20~25 % 8 Water supply 50~67 m3/h 9 Water supply pressure 0.2~0.6 MPa 10 Flange of water supply pipe PN1.0, DN100 11 Lubrication type for bearing Grease 12 Rotating speed of main bearing 42 r.p.m 13 Motor parameters

Motor model Y225M-6 Shaft power of motor 26 kW Motor power 30 kW Motor rotating speed 980 rpm Power voltage 415 V Motor insulation class F Motor protection degree IP55 Motor connection mode Y

14 Parameters of speed reducer Reducer type cycloidal-pin wheel Reducer model BWY45-23-30 Transmission ratio 1:23 Output rotating speed 42 rpm Motor insulation class F Motor protection degree IP55 Driving mode Chain

15 Case material 16Mn 16 Case thickness 10 mm 17 Noise 85 dB(A) 18 Weight 6800 kg

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7.2 Fluidizing blower Item Unit Data Data Data Model Y280S-4 Y160M-4 Y250M-4 Rated power kW 75 11 55 Rated voltage kV 415 415 415 Synchronous speed r/min 1480 1460 1480 Startup current A 70.4 22.6 102.5 Rated current A 70.4 22.6 102.5 Frequency Hz 60 60 60

Primary properties

Efficiency % 91.8 88 92.6 Power factor 0.87 0.84 0.88 Stall torque (Times) 1.9 2.2 2 Stall current (Times) 7 7 7 Max. torque (Times) 2.2 2.2 2.2

Insulation class F F F Weight kg 303 130 425 Cooling mode Air cooling Air cooling Air cooling Rotating direction Clockwise (viewed from drive end)

8. Dry ash unloader

No. Name Parameter Unit 1 Model ZSJ200D 2 Handling capacity 200 t/h 3 Diameter of discharge pipe Φ350 mm 4 Specification of flange at ash entrance PN 0.6, DN300 5 Specification of flange at ash discharge interface PN 0.6, DN125 6 Travel of unloading head 2000 mm 7 Lifting speed of unloading head 0.1 m/s 8 Parameters of lifting motor

Motor model YEJ90S-6 Motor shaft output 0.5 kW Motor power 0.75 kW Motor rotating speed 940 rpm Power voltage 415 V Motor insulation class F Motor protection degree IP55 Motor connection mode ‘’Y’’

9 Parameters of dusting blower Flow rate 824 m3/h Air pressure 3660 Pa Specification of dust outlet flange PN0.6,DN125 Motor model Y100L-2 Motor shaft output 2.6 kW Motor power 3 kW Motor rotating speed 2880 rpm Power voltage 415 V Motor insulation class F Motor protection degree IP55 Motor connection mode ‘’Y’’

10 Type of bin level indicator Solid tuning fork type Model of bin level indicator FTN50

11 Noise 85 dB(A) 12 Weight 550 kg

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5. Bag dust collector on silo top

Type and model: MDQ200;

Quantity: 8 sets;

Manufactory: Shanghai Zhongfen Electrics Co., Ltd.

Air filtering volume: 320m3/min;

Filtration area: 200m2 /set;

Filtration efficiency: >99.9%;

Air volume blown by pulse: 3.5 m3/min;

Air-blowing pressure of pulse: 0.5 -0.7MPa;

Overall dimension of filter: 8060x3860x4500mm;

Filter weight: 15371Kg;

Number and dimension of bags: 260bags/ φ120X2050mm;

Bag air/cloth ratio: 1.21m3/min/m2;

Filtration resistance: 1200 Pa;

Filtration velocity: 0.8 m/min;

Working temperature: 180 (MAX);

Time required for replacing a bag: 40hours;

Service life: 30000h;

Total weight: 15371Kg.

6. Surge tank (equipped with fluidizer)

Type: Steel structure;

Quantity: 24;

Volume: 100 m3;

Design pressure: constant pressure;

Overall dimension: φ6000X15000mm;

Weight: 20 T.

7. Motor data

7.1 Ash silo unloading system

Item Unit Data Data Model Y225M-6 YEJ90S-6 Rated power kW 30 0.75 Rated voltage kV 415 415 Synchronous speed r/min 980 920 Starting current A 59.5 4 Rated current A 59.5 4 Frequency Hz 60 60

Primary properties

Efficiency % 92.4 76.8 Power factor 0.84 0.764 Stall torque (Times) 2.18 2.41 Stall current (Times) 5.8 4.22 Max. torque (Times) 2.17 2.2

Insulation class F F Weight kg 272 32 Cooling mode Air cooling Air cooling Rotating direction Bi-directional, viewed from drive end

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4.2 Air preheated fluidizing air heater for ash hopper No. Name Parameter Unit Remarks

1 Manufactory Zhenjiang Power Station Auxiliary Equipment Plant

2 Type Horizontal type 3 Model DYK15(II) 4 Quantity 12 Set 5 Power 15 kW 6 Voltage 415 V 7 Heating air flow 3.5 Nm3/min 8 Max. allowable air temperature 150 9 Specification for outlet and inlet flange DN100 10 Temperature control precision 0.5 Grade 11 Temperature control range 0~400 12 Type of temperature measurement Double 13 Measurement range of temperature measurement 0~400 14 Power of each heating element 2.5 kW 15 Design pressure of the case 0.8 MPa 16 Insulation class F 17 Weight of each heater 175 kg

4.3 Fluidizing air heater for ash silo No. Name Parameter Unit Remarks

1 Manufactory Zhenjiang Power Station Auxiliary Equipment Plant

2 Type Horizontal type 3 Model DYK80(II) 4 Quantity 4 Set 5 Power 80 kW 6 Voltage 415 V 7 Heating air flow 21.16 m3/min 8 Max. allowable air temperature 150 9 Specification for outlet and inlet flange DN150 10 Temperature control precision 0.5 Grade 11 Temperature control range 0~400 12 Type of temperature measurement Double 13 Measurement range of temperature measurement 0~400 14 Power of each heating element 4.44 kW 15 Design pressure of the case 0.8 MPa 16 Insulation class F 17 Weight of each heater 220 kg 4.4 Fluidizing device at silo bottom No. Name Parameter Unit Remarks

1 Manufactory Zhenjiang Power Station Auxiliary Equipment Plant

2 Type Side air intake 3 Model KXC150 4 Quantity 720 m 5 Size of fluidizing device (width × thickness) 150X25 mm�mm 6 Air penetrability of fluidizing plate 0.6~0.8 m3/m2×min 7 Max. allowable temperature of fluidizing device 300 8 Resistance of fluidizing device 4 KPa 9 Weight of fluidizing device 16.5 kg/m

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3.3 Fluidizing blower for ash silo

No. Name Parameter Unit Remarks 1 Fluidizing blower 1.1 Model SNH811 1.2 Quantity 6 Set 1.3 Flow rate 21.16 Nm3/min 1.4 Outlet pressure 90 KPa 1.5 Outlet temperature 111 1.6 Driving mode Driving belt 1.7 Fan series Single-stage % 1.8 Cooling mode Air cooling

1.9 Noise (noise one meter away from equipment case and ground should not exceed) 85 dB(A)

2 Motor 2.1 Model Y250M-4 2.2 Bearing power 47.8 kW 2.3 Electric power 55 kW 2.4 Number of rotates 1480 r.p.m 2.5 Power voltage 415 V 2.6 Motor insulation class F 2.7 Motor Protection degree IP54 2.8 Motor connection mode ‘’Y’’ 3 Blimp cooling fan 3.1 Electric power 0.18 kW 3.2 Motor Protection degree IP54 3.3 Motor insulation class F 4 Total weight of equipment 1450 kg

4. Fluidizing air heater In the project, each boiler is equipped with 2 fluidizing air heaters for dust collector ash hopper, 12 of which, located in fluidizing blower chamber, are set for unit 6X600MW. Each boiler is allotted with 2 air preheated fluidizing air heater for ash hopper, 12 of which are set for unit 6X600MW. Fluidizing air heater are set indoor close to boiler and 6 fluidizing air heaters for ash silo are set for 4 ash silos. It uses continuous operation mode. 4.1 Fluidizing air heater for dust collector ash hopper No. Name Parameter Unit Remarks

1 Manufactory Zhenjiang Power Station Auxiliary Equipment Plant

2 Type Horizontal type 3 Model DYK90(II) 4 Quantity 12 Set 5 Power 90 kW 6 Voltage 415 V 7 Heating air flow 33 Nm3/min 8 Outlet air temperature 150 9 Specification for outlet and inlet flange DN150 10 Temperature control precision 0.5 Grade 11 Temperature control range 0~400 12 Type of temperature measurement Double 13 Measurement range of temperature measurement 0~400 14 Power of each heating element 4.67 kW 15 Design pressure of the case 0.8 MPa 16 Insulation class F 17 Weight of each heater 220 kg

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3.1 Fluidizing blower for dust collector ash hopper

No. Name Parameter Unit Remarks 1 Fluidizing blower 1.1 Model SNH817 1.2 Quantity 12 Set 1.3 Design flow rate 33 Nm3/min 1.4 Outlet pressure 70 KPa 1.5 Outlet temperature 130 1.6 Driving belt 1.7 Fan series Single-stage 1.8 Cooling mode Air cooling

1.9 Noise (noise one meter away from equipment case and ground should not exceed) 80 dB(A)

2 Motor 2.1 Model Y280S-4 2.2 Bearing power 65.2 kW 2.3 Electric power 75 kW 2.4 Number of rotates 1480 r.p.m 2.5 Power voltage 415 V 2.6 Motor insulation class F 2.7 Motor Protection degree 54 2.8 Motor connection mode “Y’’ 3 Blimp fan 3.1 Electric power 0.18kW kW 3.2 Motor Protection degree IP54 3.3 Motor insulation class F 4 Total weight of equipment 1450 kg

3.2 Air preheated fluidizing blower for ash hopper

No. Name Parameter Unit Remarks 1 Fluidizing blower 1.1 Model SNH803 1.2 Quantity 12 set 1.3 Flow rate 3.5 Nm3/min 1.4 Outlet pressure 70 KPa 1.5 Outlet temperature 92 1.6 Driving mode Driving belt 1.7 Fan series Single-stage 1.8 Cooling mode Air cooling

1.9 Noise (noise one meter away from equipment case and ground should not exceed) 85 dB(A)

2 Motor 2.1 Model Y160M-4 2.2 Bearing power 9.6 kW 2.3 Electric power 11 kW 2.4 Number of rotates 1460 r.p.m 2.5 Power voltage 415 V 2.6 Motor insulation class F 2.7 Motor Protection degree IP54 2.8 Motor connection type ‘’Y’’ 3 Total weight of equipment 560 kg

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ash silos. The air source for conveying is supplied by air compressor of dust collector. The largest

conveying distance is approximately 1000meters (excluding lifting height).

2. Design parameters of system

No. Item : Secondary ash handling system 1 Ash volume of design coal : 114.0 t/h 2 Ash volume of checked coal : 142 t/h 3 System output : 240 t/h 4 Conveying distance : 1000 m 5 Number of ash hoppers per electric field : 8 Piece 6 Ash deposit proportion : 0.75 t/m3

7 Gas velocity at pipe terminal : 30.8 m/s 8 Initial temperature : 110 9 Selected conveying pressure : 2.35 Bar 10 Fr(min) : 6.5 11 Ash distribution conditions : 8 vessel transporters 12 Normal : 240 t/h 13 Volume after resting : 10 m

14 Pump diameter : 300 mm 15 Pump quantity : 2 16 Number of units for each pipe : 4 17 Time for single cycle : 225.0 s 19 Max. system output : 240.0 t/h 20 System gas consumption(T) : 120.0 m3/min 21 Average gas consumption(T) : 208.0 m3/min 22 Ash air ratio : 11.9 23 Segment 1 Segment 2 Segment 3 24 Diameter for each segment : 0.3 0.4 0.4 m 25 Bend quantity : 3.0 3.0 4.0 26 Vertical climb : 0.0 0.0 30.0 m L7 Length of each segment : 340.0 340.0 320.0 m 28 Velocity at fore-end : 11.1 11.1 11.1 m/s 29 Velocity at terminal : 15.1 14.5 15.0 m/s 30 Resistance : 0.9 0.6 0.9 Bar 31 P2 : 3.4 2.5 1.9 Bar 32 P1 : 2.5 1.9 1.0 Bar 34 2.35 Bar

3. Fluidizing blower

In this project, each boiler is equipped with 2 fluidizing blowers for dust collector ash hopper and there are

totally 12 fluidizing blowers for dust collector ash hopper in unit 6X600MW. Fluidizing blowers are

located in chamber of fluidizing blower. There are two air preheated fluidizing blowers for ash hopper for

each boiler and totally 12 sets of air preheated fluidizing blowers for ash hopper for unit

6X600MW.Fluidizing blowers are arranged outdoor close to boiler and there are 6 ash silo fluidizing

blowers for 4 ash silos. The fluidizing blower uses continuous operation mode.

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PART 2 Pneumatic Ash Handling Chapter 1 Equipment Overview

1. Pressure concentrated phase pneumatic ash handling system is applied to secondary ash discharge under

intermediate bin of coal-fired unit 6X 600 MW of this project. One boiler is a conveying unit and there are

6 conveying units in total. Conveying system employs LPT type vessel transporter to send ash to terminal

ash silo. There are two terminal ash silos for three boilers, each of which has 4 intermediate bins. And each

bin is equipped with 2 ash hoppers and there is one LPT transmitter under each ash hopper. Each primary

ash conveying system has two ash conveying pipes and each pipe has one silo top changeover valve and

one discharge box at terminal located at ash silo, on which two bag dust collectors are arranged. Every

conveying pipe is equipped with 4 transmitters LPT10000 in four units, each of which includes one

transmitter and one discharge valve while the pipe diameter is DN300-DN350-DN400. Transmitter of each

unit has one set of air inlet valve block on initial end. Another set of air inlet valve block is arranged after

discharge valve on each ash conveying pipe. Each boiler is a control unit and each transmitter has one local

control box which is also arranged at blowing valve block and changeover valve over ash silo. Each ash

silo has three bin level indicators (high, low and continuous bin lever indicator). Each transmitter is

installed with one bin level indicator. In this project, each boiler air preheated has 8 ash hoppers in total;

hence unit 6×600MW totally has 48 ash hoppers.

Coal-fired unit 6X600MW of this project is equipped with 4 ash silos with reinforced concrete structure

(Ash silo no. is 1, 2, 3, 4 respectively). The diameter of each ash silo is 15m and the effective volume is

3970m3. Two ash silos can store fly ash produced from worst coal fired no less than 12 hours in three

boilers under BMCR working conditions. Ash silo ash unloading system is a system guaranteeing the

normal ash unloading of the ash silo. All equipments of this system are located over the ash silo operating

layer; when discharging ash, equipments in system should apply continuous operation mode. Diameter of

each ash silo is Ø15 m and the silo height is 38.5m while the stored ash height is 24m.

Ash handling system of this project applies vacuum conveying system first to collect fly ash from ash

hopper of dust collector, air preheater and economizer into the surge tank and then into ash silo through

pressure pneumatic conveying system. Output of pressure and vacuum pneumatic conveying system should

be no less than 200t/h according to the requirement in contracts and technical documents.

Vacuum pneumatic conveying system means that ash hoppers in one electric field of electrostatic dust

collector are connected in series with ash hoppers in three bins of bag dust collector through one pipe and

there are 8 pipes in two electric-bag dust collectors. Two adjacent pipes will be combined into one pipe,

hence there would be four pipes in total, which will be connected to four surge tanks respectively, supplied

with air source by vacuum pump and the fly ash in ash hopper will be conveyed into surge tanks. Output of

each pipe is 50t/h.

Pressure pneumatic conveying system means: two pneumatic conveying devices under each surge tank are

connected respectively to two conveying pipes. Each boiler has two pipes and output of each conveying

pipe is 120t/h. There boilers form a unit equipped with two ash silos. Three boilers with six conveying

pipes are connected to two ash silos and each pipe can convey fly ash in surge tank respectively into two

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bag and bag cage is applied. 6) Check the sealing property of manhole door, access door and flange to ensure its air tightness. 7) Check whether there is rain leakage in the insulation layer or rainproof facilities. 8) Check differential pressure and if the pressure pipeline is smooth. 9) Check and timely replace the gasket of bypass valve in bypass flue if there is damage. 10) Maintenance should be applied to electric apparatus and other general-purpose equipments according to its corresponding instructions and general provisions. 3.4.3 Maintenance Only after three-year operation, the overhaul will be implemented and it lasts 5 to 15 days. The content of overhaul is a thorough maintenance and adjustment based on the equipment conditions according to the faults checked but not resolved timely in medium and minor overhaul, damaged and rusted parts and wearing and normally aging parts need to be replaced. Preparation before overhaul should be performed as the below table:

Repair items Techniques and Precautions Quality standard

Work out maintenance plan

Check operation parameters of electric field before electric-bag compound dust collector stops running(secondary voltage, current, operation rate, operation hours and so on), operation parameter of ash removal system and spray cooling system, equipment defects, the last summary of overhaul and maintenance records since the last overhaul(such as the technical measures for improvement, replacement with spare parts or repair pieces), and work out overhaul plan through in-depth analysis of various materials: Work out maintenance control schedule, technique process, labor organization plan and the matching condition; Draw up detailed regulations of technique and safety for major special projects.

The plan is to be approved by technology department; and to be checked by safety supervision department if major safety measures are involved.

Make material preparation and site layout

Material preparation work includes the preparation of materials, spare parts and repair pieces, safety tools, construction equipments, instruments and meters, lighting appliances. Maintenance site layout work includes site cleaning, dividing of working area and material stacking area, management measures of field spare parts and so on.

Safety tools should be checked by full-time or part-time safety officer; the lighting appliances inside electric field should be torches or 12v portable lighter. If 220V lighting or power maintenance is needed, electric shock protector should be installed and knife switch should be mounted in conspicuous place outside of manhole door which is to be protected by specially-assigned person.

Prepare relevant tables for technical records

There should be tables for electrodes spacing test record , record card for test of electrified unload electric field with voltage rising and recording tables required in air distribution test, rapping acceleration measuring, air leakage rate measuring (if necessary).

Take safety measures

Process various work sheets and take safety measures strictly according to relevant security operation regulations.

Checked and accepted by work approver jointly with maintenance head on site.

17

3.3 Regular maintenance 3.3.1 Check regularly if rapping device is working normally. 3.3.2 Each heater should keep working when dust collector is disabled temporarily. 3.3.3 During temporary shutdown period, each rapping device should keep rapping for more than 10 hours before it stops. 3.3.4 Each shift should open ball valve once at air bag bottom of bag ash removal system to release the condensed water produced by compressed air in air bag. 3.3.5 Regularly check the acting situation of each pulse valve in bag ash removal system and handle it timely when it doesn’t act. 3.3.6 Regularly clean the filter of lifting valve air passage triplet and regularly fill clean engine oil into oil sprayer. 3.3.7 Regularly check acting situation of lifting valve. 3.3.8 Regular maintenance should be applied by electrical personnel to the below devices: 3.3.8.1 Regularly test and check high voltage silicon rectifier transformer and test its insulation resistance, which should be close to zero when high voltage forward against the ground and should exceeds 1000MΩ when it reverse against the ground. That of primary sides should exceed 300MΩ. 3.3.8.2 Perform a withstand voltage test per year for transformer oil and average of puncture voltage should be more than 35kV/2.5mm. 3.3.8.3 Grounding resistance should be tested per year and it should be less than 2Ω. 3.3.8.4 Fault trip circuit action test should be performed each year. 3.4 Repair/Maintenance 3.4.1 Minor repair Minor repair should be performed every six-month operation of electric-bag compound dust collector, which mainly includes: handle inner equipment faults, clean ash deposit inside electric field, check and adjust anode rapping system operation condition, check and adjust the deformation of space between electric field electrodes, wipe up insulation porcelain pieces, check whether ash discharging system is smooth, rectify indicating instrument, check the accurate situation of temperature measurement, check the sealing situation of ash removal air passage and the fastening of blow tube, check the changes after filter bag and bag cage is applied. 3.4.2 Medium repair After about one-year operation, a medium repair should be performed which will last 2 to 5 days with the content as follows: 1) Clean ash deposit inside electric field and check space between electric field electrodes to make sure deviation doesn’t exceed the specified value. 2) Check the internal parts and just simply cut off the discharge electrodes if it is broken or unsoldering and replace with new one if time allows. 3) Check whether the anode rapping hammer is at the valid position of center area of rapping anvil, and adjust it properly if there is deviation. Check the wear situation of rapping bearing and hammer and replace with new ones if the wear is serious. 4) Check, replace and clean the insulated bushing and porcelain shaft if there is damage or wear to guarantee its insulation performance. 5) Check the sealing of ash removal air passage and fastening of blow tube. Check the changes after filter

16

No. Fault Causes analysis Solutions

3 Resistance of latter-stage bag rises rapidly

Dust collection efficiency of the former-stage dust collector declines, and dust concentration in latter-stage bag dust collector increases.

(1) Operation condition of former-stage electric dust collector is poor or has fault. Adjust the secondary voltage and current of electric field and shorten rapping period. (2) Former-stage electric dust collector fault cannot be eliminated temporarily/ Shorten ash removal pulse interval properly.

4 There is obvious visible flue gas in chimney outlet.

(1) New filter bag is applied and dust collection is not stable yet. (2) Particular filter bags are damaged.

(1) Dust collection will go steady after the new filter bags are in operation for several weeks. (2) As to the compartment with checked differential pressure less than outlier, close the lifting valve of this compartment to get blocked off or replace the damaged filter bags.

5

Differential pressure of certain chamber deviates the normal value obviously

Particular filter bags are damaged in the chamber. See the treatment process in 4(2)

6 Pulse valve solenoid coil has been turned on but pulse valve fails to act.

(1) Air passages released pressure in pulse valve outer chamber are blocked. (2) Electromagnet fault.

(1) Check or clear air passages released pressure in pulse valve outer chamber. (2) Replace solenoid coil.

7 Air bag pressure alarm Pressure beyond limit is not within range of 0.2~0.3Mpa.

(1) Air source pressure or output of compressed air is insufficient. (2) Seal the leakage point as there is relatively big leakage in air passage. (3) Clear out the foreign body as piston of pressure reducing valve is blocked with foreign body.

8 Lifting valve fails to act.

(1) Cylinder solenoid valve doesn’t conduct. (2) Air pressure supplied is insufficient.

(1) Replace the solenoid valve. (2) Check air passage.

9 Obvious sound of air leakage in air bag can be heard.

(1) Ball valve at air bag bottom is closed incomplete. (2) Connecting pieces of air bags are not sealed. (3) There are impurities in diaphragm outlet of pulse valve.

(1) Close ball valve at air bag bottom. (2) Lock tight connecting pieces of air bags. (3) Conduct the pulse valve manually and clear impurities in diaphragm outlet. Cut off the air source for air bags when necessary and dismount pulse valve to clear impurities when pressure declines.

10 Air escapes from blowhole of cylinder reverse flow valve.

Inner piston of reverse flow valve is stuck by foreign body.

Open the end-cap of reverse flow valve with Allen wrench and pull out the piston to remove foreign body and get piston installed.

11 Bag pastes.

High moisture and low temperature of flue gas causes dew condensing, high viscidity between dust and filter bag. And the ash removal becomes invalid.

After the dew condensing phenomenon is removed, filter bag pressure will restore naturally.

15

No. Fault Cause analysis Solution

11

Primary and secondary current and voltage is normal but the dust collection efficiency is not satisfactory.

(1) Air distribution plat holes are jammed and the air isn’t distributed evenly. (2) Baffle plate of ash hopper and the case has dropped off and the air flow has short circuit. (3) Ash discharge device near outlet has serious air leakage problem and inlet air volume is out of limit. (4) Secondary dust flying. (5) Flue gas condition has changed.

(1) To check whether the rapping device of air distribution plate works. (2) Check the baffle plate for proper treatment. (3) Strengthen the sealing of ash discharge device and handle the reasons for air leakage. (4) a. Adjust the rapping force, time and period; b. Improve air distribution c. Enhance the sealing and adjust switch board and the whole system for less air leakage. d. Apply wet ash removal e. Reduce the air speed of electric field f. Provide ash collection device at outlet of electric dust collector. g. Prevent back corona from happening h. Adjust spark frequency control i. Improve dust resistance ratio (5) Improve flue gas condition

12 Flashover is too frequent and ash collection efficiency declines.

(1) Except electric field, other parts like isolation switches, high voltage cable and damping resistor discharge. (2) Spark frequency of electric control cabinet is not properly adjusted. (3) Rapping periodic time of front electric field is not up to standard. (4) As the working condition changes, flue gas condition fluctuates a lot. (5) Tap is not adjusted properly.

(1) Handle the discharge parts. (2) Adjust spark frequency potentiometer and set it to automatic state. (3) Adjust rapping period. (4) After boiler is disabled, enter the electric field for inspection and eliminate the abnormal discharge parts. (5) Notify shift supervisor for adjusting technological condition and improving flue gas condition. (6) Adjust the tap position.

3.2 Fault causes and solutions of bag system

No. Fault Causes analysis Solutions

1

Preheater outlet temperature keeps constant rapid rising and control system gives overtemperature alarm

Boiler may has tail combustion

Contact boiler center console. Stop the boiler resolutely when temperature keeps rising up above 190 in case the filter bags are burnt.

2

Preheater outlet temperature suddenly drops sharply and the control system gives ultra-low temperature alarm/

Boiler may has tube explosion fault

Contact boiler center console and stop boiler resolutely when it drops below dew point temperature in case dew condensing causes bag paste and wall wetting.

14

No. Fault Cause analysis Solution

6

Secondary current is large, but secondary voltage rise is poor or even close to zero.

Discharge electrode break causes the short circuit between dust plate and corona electrode. (2) Dew condensation of pressure-bearing insulator inner wall causes the high voltage short circuit to ground. (3) Corundum magnetic axis of cathode rapping device is damaged or short circuit to the ground is caused. (4) High voltage cable or cable terminal joint has breakdown short circuit. (5) There is too much ash deposit in ash hopper and the dust has piled up to corona polar framework. (6) Pressure-bearing insulator, supporting insulator and corundum magnetic axis are damp and covered with ash deposit and that causes creepage. (7) Back corona.

(1) Clear short circuit sundries or cut out broken corona wire. (2) Wipe inner wall of pressure-bearing insulator or raise temperature of insulation box. (3) Replace corundum magnetic axis (4) Replace the damaged cable or cable joints. (5) Remove the ash deposit in lower ash hopper. (6) Clean the pressure-bearing insulator, supporting insulator and corundum magnetic axis. (7) Change the flue gas conditions. Moisten the flue gas with steam. Chemical quenching and tempering should be implemented on flue gas and power should be supplied with pulse.

7

Secondary working current is normal or too large, secondary voltage is low with flashover.

(1) Partial distance between electrodes becomes small. (2) Sundries are hanging on dust plate or cathode electrode. (3) Cable breakdown or has power leakage.

(1) Adjust distance between electrodes. (2) Clear sundries (3) Replace the cable

8 Secondary voltage is too high and secondary current is strikingly low

(1) Rapping device on dust electrode or corona electrode is not started or doesn’t work. (2) Corona wires are wide and loose or power discharge is poor. (3) Dust density in flue gas is too large.

(1) Check and repair rapping device. (2) Analyze the reason of loose wire and take necessary measures. (3) Improve the technological processing to reduce dust density in flue gas.

9

Secondary voltage and primary current is normal. Secondary current doesn’t read.

(1) Capacitor parallel connected with milliammeter is damaged and that causes short circuit. (2) Connection lead from transformer to milliammeter is grounded at a certain place. (3) Milliammeter pointers are stuck.

Figure out the causes and eliminate faults

10

Secondary current is not stable and the milliamphere pointer is swinging sharply.

(1) Corona wire is broken and its remaining segment swings caused by flow influence. (2) Humidity of flue gas is too large and the dust resistance ratio declines as a result. (3) Cathode insulators discharge to ground surface.

Cutoff the remaining segment. Notify the technologist for proper treatment. Deal with the discharge part.

13

Chapter 3 Routine Maintenance and Treatment

3.1 Fault causes and solutions of former-stage electric filed:

No. Fault Cause analysis Solution

1

Primary and secondary voltage is low; secondary current is small. Primary current is too large and it rises rapidly out of proportion with secondary current.

There is interturn short circuit in rectifier transformer or open circuit or breakdown short circuit in silicon stack.

Perform open circuit test. If there is current in primary sides, it means there is certain part damaged inside transformer, partial excitation or short circuit. Pendant-core repair is necessary and damaged part should be replaced.

2

Voltage rises without current emerging. When the voltage is in normal operation, voltage starts declining and current emerges and rises rapidly.

(1) Dust resistance ratio is too high and it causes back corona; (2) Coal quality and processing operation is poor.

(1) Usually the power plant will improve the coal quality and processing operation to get coal fully combusted for enhancing rapping force. (2) Intermittent pulse power supply is applied.

3

Primary and secondary voltage is low and secondary current is small. The primary current is very large and when it is rising, primary and secondary current is out of proportion. The primary current will rise rapidly and mutates until nearly come to detonation fuse. There is obvious abnormal sound in transformer.

(1)Rectifier transformer low pressure short circuit fault; (2)Iron core (including core perforating bolts) insulation of rectifier transformer is damaged and vortexing is serious.

(1) Replace the low pressure package; (2) Redo the iron core insulation.

4

When primary and secondary current reaches the rated value, the primary voltage will be within 280~330V and secondary voltage within 40~50kV without flashover.

(1) Dust density is low and the electric field is without load; (2) High voltage cable and terminal head has serious leakage.

(1) Decline the rapping force; (2) Redo the high voltage cable and terminal head.

5

Primary and secondary current, primary voltage keeps normal without change. The secondary voltage indicator is swinging or it will indicate higher after power cutoff.

(1) Secondary voltmeter has loose moving coil screws; (2) Affected by charged dust of front electric field.

(1) Recalibrate.

12

field and its subordinate equipments should be disabled. Make sure the power supply and flue gas is

isolated and dust collector temperature drops below 40 and the working site has reliable grounding

connection and reliable safety measures are made. If there is toxic or explosive gas, don’t enter the electric

field immediately in case accidents happen.

4) Before entering dust collector, high voltage isolation knife switch should be put to position

“grounding” and the electric discharge part of high voltage silicon rectifier transformer output end should

be discharged with ground rod and be grounded reliably to prevent remnants of static electricity from

hurting people.

5) It is prohibited to contact discharge electrodes if there is no reliable grounding connection in advance

though the power supply is cut off in all electric fields.

6) Before entering dust collector, stored ash in ash hopper should be discharged and get it fully ventilated

and checked. Only when there is no toxic gas inside, can the work start.

7) None of the grounding devices of each parts of electric precipitation area should not be dismounted

casually.

8) Platform inside electric precipitation area maybe of corrosion as has been immersed in flue gas for

long. Special attention should be paid to the corrosion of platform at entering in case the platform damage

causes personal injury accident.

9) Confirm that there is nothing left inside dust collector before leaving the precipitation area.

10) Operating area should be well lighted and the passages should be clear and all manholes should be

closed tightly.

11

shorten properly the rapping periodic time and vice versa.

13) Control operation strictly according to electric-bag compound dust collector parameters:

A. Differential pressure of filter bag: 400~800Pa;

B. Differential pressure of dust collector inlet & outlet: 900~1200Pa

14) Strictly select ash removal type in order of priority as below:

A. Online ash removal: favored type;

B. Offline ash removal: deprecated type. Only applied when flue gas and dust is abnormally fine and

sticky and filter resistance exceeds the normal range.

C. Timing ash removal: favored type

D. Timing constant pressure ash removal.

15) Set ash removal system parameters strictly according to the below ranges:

A. Pulse pressure: 0.2~0.3Mpa, from low to high when adjusting;

B. Pulse width: 0.15S (unadjustable);

C. Working pressure of lifting valve cylinder: 0.35Mpa;

D. Pulse interval: 5~1000s;

16) Set working temperature points of bypass flue strictly according to below motioned tips:

A. It is normal when flue gas temperature≤160 , the bypass flue should be closed and protection air

passage should be open.

B. When flue temperature>160 , there is high temperature alarm; when flue temperature>180 , bypass

valve of control system should be open and lifting valve will be closed. And that time, the flue gas will be

discharged directly to dust collector outlet.

C. When flue gas temperature restores to and under 160 , lifting valve in bag area of control system will

be open and bypass valve will be closed. And then flue gas will enter dust collector as normal.

17) During temporary shutdown, each rapping device should keep rapping for more than 10 hours before it

stops.

18) When dust collector is disabled temporarily, heating devices should be kept going on working.

19) Each shift should conduct a comprehensive inspection for electric-bag compound dust collector and do

cleaning work within the scope of responsibilities. Make detailed records of abnormalities and equipment

defectors during this operation and do the shift hand over working well.

2.9 Safety precautions

As high voltage power is applied in dust collector operation, relevant regulations in Working Regulation of

Power Safety should be strictly implemented and special attention should be paid on personal and

equipment safety during operation.

1) It is forbidden to open the high voltage isolation switch cabinet and the cabinet door should be closed

tight.

2) When the dust collector is in operation, it is forbidden to open seal-capping of all doors or manholes.

If it needs to open insulation manhole door, get permission from attendant on duty and make effective

safety measures.

3) As to working inside dust collector, work sheet system should be implemented strictly and the electric

10

5) Shut down the equipment when the above mentioned points are distinguished as the ambient factors

threatening equipment.

6) There is slight creepage phenomenon in starting system and it disappears after a while.

7) There is ash block in ash hoppers but it can be removed timely.

2.8 Check and adjustment during operation

1) Operation parameters can be properly lowered (usually through adjusting current limit value for

current-limiting) to keep electric field in operation when electric equipments are overheated caused by poor

operating conditions, for example, highly arranged rectifier transformer and damping resistor is overheated

during operation under moon hot weather, components is overheated resulted from thyristor cooling fan

fault. If the former-stage electric field has a declined capacity of ash discharge, the ash can be properly

transferred to the latter stage by lowering the operation parameters of the electric field.

2) Adjustment of rapping control mode: Rapping frequency can be increased properly and rapping interval

will be shortened consequently when ash accumulates heavily on electrodes; and rapping interval can be

properly prolonged conversely.

3) When the differential pressure of filter bags in bag area rise up to 1500Pa for long, shorten the ash

removal periodic time till the differential pressure declines down to normal value.

4) The ash discharge mode is automatic ash discharge based on the high ash level. During ash discharging,

if ash level signal doesn’t work, it can be switched ion successive ash discharging. It can also be operated

in the way of simulated automatic ash discharging by programmable controller according to electric field

conditions to keep certain ash seal to ash hopper.

5) Closely supervise primary voltage and current, secondary voltage and current, flashover frequency of

power supply equipment. Records should be made per 2 hours. Each shift should check the

temperature-measuring thermometer works normally.

6) Strictly monitor temperature of preheater outlet and dust collector inlet and outlet and usually, make

records per 2 hours

7) Strictly monitor the differential pressure of filter bag, pressure of dust collector inlet and outlet, ash

removal pressure, working pressure of lifting valve, pulse interval and ash removal period. And the records

should be made per 2 hours usually.

8) Monitor the temperature rise of high voltage silicon rectifier transformer and it should not exceeds above

80 without abnormal sound. Abnormal discharge phenomenon should not happen to high voltage output

network.

9) Check each insulation box and ash hopper heater should be working normally.

10) In case of fault or misoperation for dust collector and auxiliary equipment during operation, operators

should go to site to confirm fault point immediately after receiving alarm notice, analyze the cause and

contact for treatment.

11) Each shift should check twice all motors, speed reducers, bearings and outer operating parts. Check the

lubrication of lubrication points regularly and add lubricating oil or grease when necessary.

12) Adjust periodic time of anode and cathode rapping according to dust collector inlet & outlet flue gas

condition. When the inlet flue gas density is large, secondary voltage high and secondary current small,

9

rectifier transformer and control cabinet for the sake of anti-interference;

3) Neither high voltage isolation room nor dust collector body should be entered during operation of high

voltage equipment.

4) It is forbidden to run ash removal system of bag dust collector during ash pre-coating and ignition of

boiler oil spray for combustion-supporting till the boiler burns coal at normal furnace temperature, to

prevent ash-coated layer from falling off and losing the protective effect of anti-dewing resulted from low

temperature.

5) Continuous ash pre-coating of a small quantity should be implemented when time spent on the process

of boiler ignition of oil spraying for combustion-supporting exceeds 2 hours.

6) Try to prolong the ash removing period on the condition that differential pressure of filter bag is within

the allowable range.

7) Temperature-measuring thermometer after the preheating should be timely replaced if there is a fault (or

wear) to ensure a normal operation of system.

2.6 Conditions for immediate shutdown of equipment

2.6.1 Electrical part:

1) Rectifier transformer and reactor are in high heat, temperature rise of reactor exceeds 65 , temperature

rise of rectifier transformer exceeds 40 or there are obvious flashover, arc discharge and vibration, etc.

inside equipment.

2) Damping resistance catches on fire.

3) Severe flashover occurs in high voltage insulation parts, and flashover discharge in high-voltage

pothead.

4) Power supply unit is out of control, and high current impact occurs.

5) Electric equipment catches on fire.

6) Other conditions that seriously threaten personal and equipment safety.

2.6.2 Proper part:

1) Space between opposite electrodes in electric field reduces materially, and arc discharge continuously

occurs in electric field. And there is dewfall and severe creepage of insulator.

2) Temperature of boiler flue gas rise steeply up to above 190 . There is an emergency alarm in control

system and the open temperature of bypass valves still doesn’t decline.

3) Gas temperature sharply falls below dew point temperature and there is bag paste phenomenon of the

filter bag.

4) When there is ash blockage in ash handling system and ash level keeps on rising after it reaches high bin

level, urgently stop the boiler to discharge ashes for protecting the filter bag from being damaged.

2.7 Conditions for appropriate shutdown of equipment

1) Rectifier transformer and reactor are in high heat and have already exceeded the normal allowable value.

2) Damping resistance belches fire, and power supply unit has partial excitation problem.

3) Cooling fan for thyristor is in high heat due to faults.

4) All sorts of cable heads, especially the main loop cable head and incoming line joints of rectifier

transformer and reactor are in high heat.

8

15) Check whether the air supply operating pressure of the outlet damper cylinder and bypass damper

cylinder is above 0.5Mpa.

16) Put it into insulating box for heating 12~24 hours before boiler ignition or system start-up to prevent

insulators from creepage as a result of dewing.

17) Put it into the ash hopper for heating 12~24 hours before boiler ignition or system start-up to prevent

ash hopper from cross-linking or ash clogging resulting from dewing or damp ash.

18) Ash pre-coating protection for filter bags should be conducted before the filter bag is put into operation

for the first time or after the boiler stops and cools before another start. Ash pre-coating should be done on

the day when the host is certain to ignite the boiler. When the host cannot ignite temporarily after the filter

bag ash pre-coating, ash cleaning system should be started to clean the ash layers of filter bag and to

pre-coat ash before the next start-up by host. In that way, the surface of filter bag can be protected from

being damp or pasted.

2.3 Startup of electric-bag compound dust collector

1) 12~24hours before the boiler ignites, put it into insulator heating device and temperature detecting

device in insulation box. Observe the heating situations should be normal and electric heating has insulator

room temperature rise above dew point temperature 20~30 .

2) Put it into ash hopper heating system 12~24 hours before boiler ignites. As to steam heating system, it

should be fully drained before heating system is put into operation.

3) Bypass valve should be opened and lifting valve should be all at “close” position.

4) Put the ash discharging device and rapping device into operation at time of boiler ignition or start-up of

system to start corresponding ash handling system.

5) Stop supplying oil to the boiler for combustion-supporting and start the ash removal system after the

boiler has started burning coal and running normally.

6) After it runs stably, adjust and set the secondary voltage ad current based on working conditions. It can

be switched into automatic operation after the setting.

7) Adjust the periodic time of anode and cathode rapping according to flue gas and running secondary

voltage and current conditions.

8) Set the pulse ash removal of bag dust collector according to differential pressure conditions.

2.4 Shutdown of electric-bag compound dust collector

1) After the host stop, cut off the electric field high voltage supply according to the shutdown process for

electric dust collector.

2) Keep running the anode and cathode rapping and latter-stage ash removal system of the electric dust

collector and conduct ash removing continuously for 10 ~20 periods.

3) Shut down low voltage control system after ash discharging and conveying of ash hopper is done.

4) Shut down the system blower.

2.5 Precautions for equipment operation:

1) To prevent the switches from being burnt down, do not switch the high voltage switch or directly pull

down the switches under the equipment operation status;

2) Metal-shielded wires should be applied as the feedback connection lines of current and voltage between

7

rise up to 800Pa → Ash coating; If flue gas pass through bypass flue, Clean the ash → Times of ash coating

can be less, as below: Automatic ash cleaning for a period (manual ash cleaning is also allowed) → Open

the butterfly valve of ash coating pipe → Ash car delivers the ash → Close the butterfly valve;

Notice: If flue gas passes through the bypass flue, and if it is the control cabinet controlling the bypass

valve, the ash cleaning can only be conducted manually. If the local operating box controls the bypass valve,

it will clean the ash automatically when the ash cleaning period should be shortened.

2) Precautions:

a) Ash coating volume has to do with air volume of inlet flue. The larger of the baffle opening of induced

draught fan, the larger of the air volume and the higher of spraying efficiency;

b) When cleaning → coating ash in midway, the shorter of the time, the better. It is in the order of

cleaning first and coating afterwards.

c) After a long time oil burning and boiler stop, ash cleaning should be immediately conducted followed

by ash coating which should be kept on the boiler till next ignition and operation.

d) After coal is put in and the oil is stopped to supply for combustion-supporting, if the differential

pressure of filter bag rises up above 800Pa, ash cleaning can be conducted while the ash coating can be

canceled.

2.2 Check before starting the electro-bag compound dust collector:

1) Check whether there is foreign matter in the casing and insulator box of electrostatic dust collector, if all

the manhole doors are closed tightly.

2) Check whether the platforms, stairs and handrails of each part of the electrostatic dust collector are firm

and complete, the passage is clear and the lighting is sufficient.

3) Check whether each transmission mechanism is in good condition and if each lubrication point has

sufficient lubricating oil.

4) Check whether dry ash handling system is in good condition and if each ash discharging valve is in

proper position.

5) Check that grounding device in each part should be in good condition.

6) Check whether each heating unit is in good condition and reliable.

7) Check and measure if the insulation of relevant equipment is qualified.

8) Check to make sure both the high-voltage cable head and high-voltage silicon rectifier transformer not

have oil leakage phenomenon.

9) Check to make sure each connection of the power supply unit is in good condition and reliable, no

component is loose, and operating mechanism of the high-voltage disconnector is flexible and in proper

position.

10) Check to make sure all the maintenance personnel has left the electrostatic dust collector body.

11) Check to make sure the functions of all the instruments, power switches, adjusters, monitor and alarm

signals and protection devices is in good condition.

12) Check whether the test rapping device runs normally and if the rapping device head raps on central

position of the rapping bar.

13) Check whether the pulse valves act normally.

14) check whether all the cylinders of each damper work smoothly

6

2) The state of lifting valve and bypass valve during fluorescent powder leakage detection: Lifting valve

is in open state while the bypass valve in close state and all manholes should be closed.

3) Put the fluorescent powder into the opening of inlet flue (usually pour it through pressure test hole and

details depend on the specific circumstances) on the condition that the main air blower runs at half of the

design airflow while the air removal system stops running;

4) After the fluorescent powder is put into the dust collector, the air blower should keep going on running

for at least above 20minutes to make sure the powder is distributed evenly on the filter bags in each

compartment of electric-bag compound dust collector.

5) After main air blower is closed, open the manhole door of the cleaning chamber of electric-bag

compound dust collector for inspection personnel to enter with fluorescent lamps (UV lamp) to inspect in

each cleaning chamber. There should be no fluorescent powder in clothes, hats, shoes and other parts of the

body of the inspection personnel. And the one with fluorescent powder should not be allowed to enter for

inspection. To seriously check the seam crossing of card, joints between filter bag and card in cleaning

chamber with fluorescent lamp. The dimmer it is in ambient environment, the more it will help the leakage

detection work.

6) If there is fluorescent powder (fluorescent powder displays as red under the rays of fluorescent lamp)

discovered during inspection, analyze the reason carefully and take notes. When dealing with the

fluorescent power leakage problem, if welding is needed, take measures protecting the filter bag;

7) Check the quantity of fluorescent powder around bypass flue valve plate and open the bypass valve to

check the fluorescent powder quantity at the positions of silicon rubber gasket before and after the valve

plated is pressed tight. To check whether the leakage of bypass flue is too serious and if it is, the reason

analysis must be implemented and corresponding treatment should be conducted (Usually, the reason is that

the space of valve plated press-in silicon rubber is too small. And the valve plate can be screwed slightly

down).

2.1.3 Ash pre-coating

When igniting the boiler, certain lampblack with incompletely combusted tars will enter dust collector and

get the surface of filter bags binding and pasted. If the phenomenon is temporary or intermittent, it can be

settled by “ash pre-coating” measures.

1) Operation method of ash pre-coating:

a) Principle of ash pre-coating: Filter bags should be pre-coated with ash before the boiler’s ignition and

oil burning;

b) Usually, the operation sequence of ash pre-coating when start and stop the boiler is: Make sure the

lifting valve is in open state while the bypass valve is in close state → ash tank car is in place and taken

over → Start the induced draught fan (baffle opening is above 60%) → Open the butterfly valve of ash

pre-coating pipe → Ash car delivers the ash → the filter bag differential pressure is ranged within

300-400pa→Stop ash coating and close the butterfly valve of ash pre-coating pipe;

c) Operation sequence of ash coating during long time oil burning process: System long time oil burning

requires intermittent ash coating → Ash cleaning → Ash coating. Hence there should be two ash tank cars

ready to feed and coat the filter bags during long time oil burning. If the flue gas pass by bag area, ash

coating frequency should be higher and ash cleaning is necessary when differential pressure of filter bag

5

Chapter 2 Operation & Maintenance of Electric-bag Compound Dust Collector

2.1 Work before operation

2.1.1 Cleaning of air passage pipeline

After the installation of compressed air system, put through the main air supply. When the main air supply

get all the conditions to supply compressed air, the cleaning of compressed air system pipelines should be

performed timely and welding slag and other impurities should be eliminated from the pipelines. The

cleaning must be done before the installation of filter bag cage to make sure filter bag cage is conditioned

to be installed. Specific cleaning solution is as below:

1) Close all stop valves and ball valves, and dismount one end of PU tube (copper tube) leading to

cylinders and pressure transmitters.

2) Dismount the air supply triplets in the air passage of lift valve and bypass valve.

3) Open the water drain valve at gasholder bottom and the stop valve (ball valve) in main air supply to

gasholder following, then after a period of time for ventilation, close the water drain valve at gasholder

bottom.

4) Open the stop valve mounted ahead of air supply triplet in air passage of lift valve and bypass valve to

blow the welding slag. And after a while, close the stop valve and mount the air supply triplet.

5) Open the air discharge ball valve at the medium and end of lift valve and bypass valve air passage to

blow and clean. And after it is closed, open the ball valves leading to cylinders and pressure transmitter to

be blown and cleaned.

6) Open water drain valve at filter bottom in air passage of air bag and stop valve (ball valve) in front of it

for ventilation. After a while, close the water drain valve at filter bottom.

7) Dismount the last pulse valve near inlet of the air bag in the air flow direction for compressed air

entering and turn up the air pressure of pressure relief valve. And mount the pulse valve after blowing for a

while until no obvious particles discovered.

8) Blow the air bags in the direction of outlet-to-inlet respectively according to step 7;

9) After blowing air bags is finished, open water drain valves at air bag bottom respectively for a period

of ventilation;

10) If the electrics have got all the conditions, adjust the pressure in air bag to 0.2~0.25Mpa and operate

the field end box of pulse valve to have each pulse valve work at least twice.

11) Finally, check whether there is air leakage on two joints of pulse valve and air bag. And if there is

between pulse valve and air bag pulse valve pedestal, check whether the bolts and nuts are screwed tightly.

If it is air leakage between pulse valve and air bag connecting short tube, the pulse valve should be

dismounted to check whether the gasket is broken and if it is , replace it with a ne w one to be mounted.

2.1.2 Fluorescent powder leakage detection

Leakage detection for filter bag of electric-bag compound dust collector is the “fluorescent powder leakage

detection” after the installation of filter bags for dust collector.

1) Essential conditions for fluorescent powder leakage detection: Induced draught fan works normally

and its opening fits and the air compressor is capable of supplying gas;

4

7) Required NO2 content of the flue gas: <260ppm (~450mg/Nm3).

8) Required SO2 content of the flue gas: <1600ppm (~4200mg/Nm3).

9) Ash cleaning control mode: PLC control, give priority to on-line ash removal and can switch to off-line

ash removal at any time;

8) Design pressure of case: positive pressure (+9.8 kPa), negative pressure (-9.8 kPa);

9) Pulse valve specification: 4 inches.

10) Consumption of compressed air: 35 Nm3/min (when pulse period is of adjustable minutes).

1.5 Control panel (console)

1) Number and type of control panels (consoles) for rectifier transformer per filter: 4 sets; cabinet.

2) Number and type of control panels for discharge electrode rapping, collecting electrode rapping and

channel plate rapping: 1 set, cabinet type

3) Quantity and type of control panels (set) of insulator and porcelain bushing electric heater per dust

collector: 1 set; cabinet type.

4) Quantity and type of local terminal boxes: refer to the actual quantity (sets); vertical

1.6 Ash hopper

1) Number/material of ash hoppers on dust collector: 40/Q235.

2) Capacity per ash hopper: ~127 m3.

3) Size of ash outlet flange of hopper (internal opening): 300 mm×300 mm.

4) Elevation of ash outlet flange of hopper: 3.5m.

5) Type, number of layers and material of the inlet & outlet gas distribution device: There is three-layer

resistance flow diversion type distribution board/Q235

1.7 High voltage supply system:

1) Number of rectifier transformers equipped for each dust collector: 4 sets

2) Type and weight of rectifier transformer: oil-immersed /~1.73t.

3) Mode and requirements of installing rectifier transformer: outdoor fitness type

4) Applicable altitude and ambient temperature of rectifier transformer: 1,000 m; -25-50 .

3

20m tentatively while size of outlet & inlet is 5m (width) X4m (height) tentatively.

1.2 Anode system

1) Number of flue gas passes per dust collector: 80.

2) Space between the same electrodes: 400 mm.

3) Rapping device of anode plate:

a. Type: top electromagnetic hammer rapping

b. Number of rapping device per ESP: 128 sets.

c. Rapping mode and operation mode: Top/Automatic.

d. Min. rapping acceleration: >150g.

e. Mode and location of control system: SCM (single chip microcomputer) control, control room.

f. Type of rapping device for control system:

g. Material of rapping bar: Q235, lubrication is not required.

h. If one set of transformer gets fault, the area of polar plate loses 12.5%.

4) Supporting and guiding way: rigid connection on the top, directional anti-pendulum on the lower part

and free expansion on the upper part.

1.3 Cathode system

1) Material and type of discharge electrodes: acupuncture line, stainless steel, carbon steel.

2) Discharge electrode rapping device:

a. Type of rapping device: Rapping of top electromagnetic hammer

b. Total number of rapping devices: 64 sets.

c. Rapping position: Top.

d. Operation mode of rapping device: automatic control.

e. Min. rapping acceleration: >80g.

f. Material and specification of rapping device: Q235 (carburizing treatment)

g. Control mode of rapping system device: SCM automatic control

3) Total length and number of discharge electrodes per electrostatic dust collector: ~38125m /~2560.

4) Discharge electrodes spacing in the direction of airflow: 203 mm.

5) Space between discharge electrodes perpendicular to airflow direction: 400mm.

6) Design height of discharge electrode: 15 m.

Supporting and guiding way of discharge electrode frame: Top suspension, lower directional anti-pendulum

and free expansion.

7) Number of heaters for thermo tank per dust collector: 64 sets.

1.4 Bag dust collector

1) Total compartments of bag dust collector: 2 x 4 x 3.

2) Total filtration area: 61586 m2.

3) Filter bag specification: Ø168mm×8.25m.

4) Wind velocity of filtration: 1 m/min.

5) Design resistance of bag dust collector: ≤ 950Pa.

6) Required O2 content of the flue gas: <8% while temperature≤160 , <5% while temperature ≤170 ;

2

PART 1 Electric-Bag Compound Dust Collector

Chapter 1 Overview

Technical specifications for main parameters:

1.1 Structural parameters

1) Model: 2FE480/4-2E4×3-G.

2) Type: Dry type, horizontal type, plate type and half pulse type.

3) Number of sets equipped for each boiler: 2 sets.

4) Dust collector inlet flue gas flow (per boiler): Design coal: 3709139.3 m3/h

Worst coal: 3735890.2 m3/h

5) Dust collector inlet dust content: Design coal: 51 g/Nm3

Worst coal: 63 g/ Nm3.

6) When the worst coal is fired, the max outlet dust content of dust collector is guaranteed within

50mg/Nm3 when one bag chamber or one electric field bypass or one bypass is disabled. Total electricity

consumption of two electric dust collectors per boiler is guaranteed at 651.7 kVA while that of two bag dust

collectors per boiler is guaranteed at 117.4kVA.

7) Dust collector inlet flue gas temperature (BMCR): 137 (design coal), 137 (worst coal).

8) Dust collection efficiency: ≥99.94%.

9) Dust collector proper resistance: ≤250Pa (electrostatic dust collector); ≤ 950Pa (bag dust collector);

<800 Pa (overall initial); ≤1200 Pa (end o bag f service life)

10) Proper air leakage rate: ≤2%.

11) Service life: 30 years, over 8,000 hours/year; service life of the bag is required to be longer than 35,000

hours at the operating temperature of 160 .

12) Number of electric fields per dust collector: 2.

13) Number of inlets and outlets per boiler dust collector: 4 at inlet, 4 at outlet.

Air intake and discharge directions: horizontally intake, horizontally discharge.

14) Bag dust collector requires considering adding 100% gas bypass when adopting fuel oil for boiler

startup or part load combustion-supporting. And detection and protection measures of explosion

temperature are taken.

15) Filtration velocity of bag filtration is 1.0m/min, and bag dust collector has three chambers and four

passes.

16) Length height ratio of dust collector: 1.13.

17) Noise :< 80dB.

18) Number of electric fields/single electric field length of electrostatic dust collector: 2/3.8 m.

19) Flue gas treatment time: 7.03s.

20) Effective cross sectional area of electrostatic dust collector: 480×2 m2

21) Total width of dust collector (including staircases of both sides) doesn’t exceed 75cm and total length

of column space before and after should not exceed 32.12m. Elevation of central inlet of flue air passage is

1

CONTENTS

PART 1 Electric-Bag Compound Dust Collector ................................... ..................2

Chapter 1 Overview……………………………………………………………………2

Chapter 2 Operation & Maintenance of Electric-bag Compound Dust Collector…….5

Chapter 3 Routine Maintenance and Treatment…………………………………..13

PART 2 Pneumatic Ash Handling ............................................................................ 19

Chapter 1 Equipment Overview……………………………………………………19

Chapter 2 Pneumatic Ash Conveying Operation………………………………….35

Chapter 3 Routine Maintenance & Treatment……………………………………41

PART 3 Ash & Slag System ...................................................................................... 47

Chapter 1 System Overview………………………………………………………..47

Chapter 2 Running of Slag Handling System……………………………………..57

Chapter 3 Routine Maintenance of Slag Handling System………………………60

KMPCL 6 x 600 MW Subcritical Coal-fired Power Plant Project

KSK Mahanadi Power Company Limited 6 x 600 MW Thermal Power Project Nariyara, Chhattisgarh, India

SEPCO ELECTRIC POWER CONSTRUCTION CORP.

No. AH-002 Boiler Ash Handling Operation &

Maintenance Manual Total 64 Pages

Boiler Ash Handling Operation & Maintenance Manual

Drafted by: Xu Yuguo

Reviewed by: Li Xinli

Approved by: Li Mingda