Download - 14 Focus on Cooling Tower
SPOTLIGHT ON COOLING TOWER
4 x 250 MW O.P.JINDAL SUPER THERMAL POWER STATION, JPL-
TAMNAR
Presented By:Mr. U. K. MondalMr. Pradeep Kumar
Flow of PresentationCompany Profile
Salient Feature of the (4X250 MW) OP Jindal STPP
Requirements of Cooling Tower
JPL experience with the performance of cooling tower
Challenges faced in the Commissioning/Operation of cooling tower
Expectation from the Vendors
Conclusion
Company Profile
• First Mega Power Project of 1000 MW in thePrivate Sector.
Salient Feature of (4X250 MW) OP Jindal STPP
• JPL’s 4 units of 250 MW Capacity each hasbeen installed at Tamnar-37 KM fromRaigarh -Chhattisgarh.
• BTG is supplied by BHEL.
• All 4 Units Commissioned from September-2007 to July 2008.
Continued…
• Established 258 KM long 400 KV Double
circuit transmission line for Power Evacuation.
• Construction of 18 Mtr high Dam over the
river Kurket to meet water requirement.
• Reservoir Capacity is approximately
35MCuM
• Self sustaining Coal source from the Captive
coal Mines located at Dongamauha 8 KM
from the plant.
• Total Coal Reserve of the mine is 247
Continued…
• Coal Transportation by Cross Country Pipe
Conveyor 6.9 KM Long .
• Second longest Pipe Conveyor in the world
Unit Heat Rate : 2248 Kcal/KWh @100% MCR (for 0% make up)
Boiler Efficiency : 86.79%
Turbine cycle : 1951 Kcal/hr.
heat rate
Coal Consumption : 157 MT/Hr/Unit
CV of coal : 3600 Kcal/Kg
A P Consumption : 9%
(as per CERC’s guideline)
DM water make-up : 3 %
Major Design Parameter
Plant Load Factor & Availability in %
Financial Year
Perc
enta
ge
Plant Performance Indices
75
80
85
90
95
100
Fy 08-09 FY 09-10 FY 10-11 FY 11-12
PLFAvailability
NEED OF COOLING TOWER : In Powerplant, cooling tower cools down the hotwater of Turbine Condenser by theprocess of evaporative cooling andsensible heat transfer. This cold water isrecycled into the system again forcondensation of exhaust steam inCondenser.
Condenser act as heat load and coolingtower plays an important role inmaintaining vacuum in condenser.
Requirement of Cooling Tower
S.No Details Description
1 No. of Cell per Cooling Tower 14
2 Vendor Paharpur
3 Tower Model 86042-5.0-14
4 Tower Type Induced Draught Counter flow
5 Circulating water flow(CMH)per tower 40000(in 13 operating cell)
6 CW inlet temp( deg C) 42
7 CW outlet temp( deg C) 33
8 Ambient Wet bulb temp.(deg C) 28.5
9 Cooling Range(deg C) 9
10 Approach to Ambient WBT(deg C) 4.5
SPECIFICATION OF COOLING TOWER
Performance measured by using term “Effectiveness” in percentage is the ratio of range to the ideal range i.e., difference between cooling water inlet temperature and ambient wet bulb temperature, or in other words it is
= Range / (Range + Approach).
“Range” is the difference between the cooling tower water inlet and outlet temperature.
“Approach” is the difference between the cooling tower outlet cold water temperature and ambient Wet bulb temperature
Performance of Cooling Tower in JPL
Effectiveness of our cooling towers are tabulated below:
The effectiveness of Cooling tower is tested once in a year byO&E Team & National Productivity Council, Delhi.
The effectiveness of cooling tower is calculated bymeasurement of CT fan current, Qty of water flow throughriser pipe, Temperature of CT outlet and CT inlet Water.
Continued…
S No Unit Design Effectiveness
Observed Effectiveness
ObservationDate
1 1 66.67 % 64.7 % 16 Aug 11
2 2 66.67% 58.12 % 22 Aug 11
3 3 66.67% 66.67 % 24 Aug 11
4 4 66.67% 51.41 % 17 Sep 11
WBT
DBT/ Relative Humidity
Heat Load
Range/Approach
Heat Transfer in the cell
Recirculation
Factors affecting the performance
Cleaning of fill (film fill) by using air to prevent the clogging of fill otherwise itwould reduce the effective heat transfer area.
Cleaning of Fan blades as the dust/algae deposition on fan blades wouldincrease its weight and power consumption of motor. Cleaning would alsoclean the path on blade for large volume of air to flow and increase theefficiency of fan blades.
Replacing/Repairing damaged diffuser rings , Nozzles, Branch Arms to makethe distribution of water uniform over the fills.
Cleaning of fan cylinder and Drift Eliminators for efficient working of system
Action taken to increase the performance during shutdown
Rectification of grouting work with quick settling compound GP2between Distribution pipe sleeve with hot water duct. Otherwisedistribution pipe could loose and fall down causing heavy flow ofwater to fall on the fill at a greater pressure and damage thefills, consequently reducing the performance of cooling tower.
Servicing of gearbox of riser pipe valve and its actuator to avoid theproblem of jamming of valve.
Continued…
Large elevation diff. between Motor base and Gear box base
Disengagement of Distribution Pipes while running and Missing of
sleeves in some places
CT Water outlet sluice gate isolation problem at common duct
Fitting of faulty Nozzles, Diffuser Rings and Branch Arms or Missing
items in some places
Problems in Draining of CT basin Water during AOH
Challenges Faced During Commissioning & AOH
Reason for elevation difference b/w Motor Base and Gearbox Base
Faulty civil work in foundation at either motor base or Gearbox base.
Use of in-appropriate number and thickness of shim
The elevation difference will result into: Abnormal vibration of Motor, Gearbox
Abnormal sound of Motor, Gearbox
Bearing failure of Motor, Gearbox
Elevation diff b/w motor base and gearbox base
Solution
Water level checking of base. One end of level gauge should bemeasured at Gear Box coupling end and other end should bemeasured at Motor coupling end.
Adjusting the level by use of shims either on Motor base or Gear boxbase depending upon the level slope.
Continued…
Reasons for Disengagement of distribution pipe
Improper Grouting
Missing Sleeves in distribution pipe
Use of low quality cements for Grouting
Disengagement of Distribution Pipe while Running will result into
Damage of fills pack
Non-Uniform distribution of water over the fills
Reducing effectiveness as the effective heat transfer area decreases.
Disengagement of distribution pipe while running
Solution
Check for Missing Sleeves, repair/fitting of sleeve if any.
Proper Grouting of Distribution Pipe and checking of grouting after some hours by pouring water into it.
Grouting with GP2 cement or any other good quality quick settling cement.
Continued…
Reasons for Fitting of faulty parts
Shortage of Materials at the time of Erection/Commissioning
Pressure of Achieving the target within scheduled date
Fitting of faulty parts or Missing of Parts will result into
Improper Distribution of Water over the fills Reducing Efficiency Channelization Missing of Grommets or fitting of faulty Grommets
could result failure of Fan Blades
Fitting of Faulty parts
Solution
Proper checking of Faulty or Missing Parts Repair/Replacing the faulty or Missing Parts as early as possible
Continued…
Reason for improper draining of CT Basin Uneven slope in CT basin
Improper slope will result into Water clogging at the basin of some cells of cooling
tower Downtime increases Using More Manpower/Machine/Money
Solution Forming small pits at some cells to collect the
sludge and water Dewatering water from small pits by using pumps
Draining of CT basin during shutdown
Abnormal Sound / Vibration in Motor or Gearbox housing
Non-Uniform distribution of water
Challenges faced during operation
Reasons for abnormal sound/vibration
Misalignment Elevation Difference Unbalancing of Drive Shaft Gearbox/Motor Bearing Failure Cooling Fan hitting Guard Bending of Motor Shaft/Gear Box Shaft
Abnormal Sound/ Vibration will result into
Failure of Motor Bearing/Gear Box Bearing Overloading of Motor Failure of Gears teeth
Abnormal sound / vibration in motor or gearbox
Solution
Correction of Alignment b/w Gearbox to Drive shaft coupling, Drive Shaft to Motor Coupling if any
Checking elevation b/w Motor Base and Gearbox Base and doing correction by shims if any
Checking for any Unbalancing of rotors(Drive Shaft) and making correction by adding counterweights if required.
Checking of gromets and replacing if necessary
Continued…
Reasons for Non-Uniform Distribution of water Absence of Diffuser ring or fitting of damaged
diffuser ring Absence of Nozzles or fitting of damaged Nozzles Absence of End cap or end cap broken while
running Disengagement of Distribution Pipe Problem in operation of Riser valve Gearbox
Non-Uniform Distribution of Water will result into Effective heat transfer area decreases Damaging of fills pack Reducing performance of cooling tower
Non-uniform distribution of water
Solution
Replacing damaged Nozzles/Diffuser ring.
Inspecting the cooling tower at regular interval to find heavy flow of water falling through fills and checking inside the tower after isolating it.
Greasing of riser valve gearbox periodically to prevent from jamming of gearbox
Continued…
Corrosion resistance coating in RCC hyperbolic structure
Replacement of GRP fan blades with Energy Efficient FRP Hollow Fan blade
Saving in Auxiliary power consumption and Reducing Maintenance by use of Direct Drive System.
After sale service must be satisfactory.
Expectation from Vendors
Corrosion resistance coating inside hyperbolic RCC structure of cooling tower is done usually by Epoxy Paint. Sometimes it is done after sand blasting to remove the debris/dust etc.
Advantages
Increase the life of CT components
Increase the Performance of Cooling tower
Also good for safety point as it prevent of the growth of algae
Corrosion resistance coating
Existing GRP fan blades can be replaced with the Energy Efficient FRP Hollow Fan blades
Advantages
Increase the efficiency of fan blades
FRP blades are lighter than GRP blades result in Saving of saving in aux power consumption
Replacement of fan blades
Cooling tower direct drive is direct mounting of fan blades with fan hub cover on the vertical motor as different to the conventional cooling tower drive
Advantages
Low Maintenance due to elimination of Drive shaft and Gearbox
Low Maintenance cost
Power saving as speed of Motor is variable
Using Direct cooling tower drive
After sale service by vendors to customers may include giving seminars/conference on the advancement of technologies in concerned areas, brain storming, maintenance or repairing of items.
After sale-service
Cooling tower plays a vital role in power plant. To achieve the high effectiveness of cooling tower we can look for advancement in technologies( as discussed ) and maintaining and improving operation practices.
CONCLUSION