3 February, 2014

REPORT ON TROUBLESHOOTING BOILER COMMISSIONING PROBLEM

By Venus energy audit system

The visit was made to study the operational problems experienced in the newly commissioned 72 TPH AFBC boiler. The boiler was under shut down at the time of visit for ID fan capacity check and for breaking part of the waterwall refractory lining above the SSH. The boiler was later started and operated with 1st & 2nd compartments and with 2nd & 3rd compartments with stable bed conditions.

About the boiler

The boiler main steam parameters are 72 TPH, 86 kg/cm2g, 520 deg C with a feed water temperature of 201 deg C at economiser inlet. The boiler is designed for Indian coal of 2353 kcal/kg GCV. The design coal will have 12% moisture and 49.7% ash. The boiler is a single drum boiler, without bed SH. The SSH is a radiant cum convection SH. The primary SH is in two parts and is designed as convection SH. All the SH assemblies are non drainable. APH is sized for 195 deg C air temperature.

The boiler is with 3 compartments. First compartment is sized less and is provided with one drag chain feeder. The 2nd and 3rd compartments are twice the size of 1st compartment and are provided with two feeders each.

The waterwall surfaces between the SSH and the bed coils are covered with refractory in order to increase the inlet gas temperature to SSH. Also the waterwall surfaces between the SSH and the PSH are covered with refractory in order to increase the heat pick up by the PSH.

The start up compartment is only half of the 2nd/ 3rd compartment area. The start up compartment is located below the nose panel. The start up burners are mounted on the rear waterwall (below the nose panel.

The FD fan and ID fan are provided with VFD. BFP is provided with VFD.

The problems reported

The following problems were reported based on the commissioning experience in the last one month.

1. Main steam temperature could not be controlled when the 3rd compartment is activated. The turbine had tripped at times on high steam temperature.

2. The spray is becoming limitation during the 3rd compartment activation. The DESH nozzle size was increased from 12 mm to 14 mm. It is suspected that the spray water line is undersized.

3. The oxygen levels are very high in the flue gas. It could not be reduced. The oxygen level at APH inlet had been around 11.5%. About 1% increase is seen at ID fan inlet.

4. Chimney is pressurised. At ID fan discharge the draft is positive. 5. The ID fan seems undersized. Its rpm loading was more than 85% during three compartments

operation but with O2 at 11.5% at APH inlet. 6. It is suspected there is APH to ESP gas ducting is undersized.

DIAGNOSIS

Review of the log sheets dated 25th and 26th January 2014

The log sheets generated by DCS on 25th and 26th January 2014 were reviewed. The following are the observations.

The bed temperatures of 1st and 2nd compartments were erratic. See photo 1 in annexure 1.1. This meant that the steam generation was less at bed coil. Since the remaining part of the evaporative surface was also covered with refractory, poor bed condition will result in high SH temperatures. At the time of visit the boiler was in shut condition. The refractory height above the SSH was being reduced by 2 m, which was decided by OEM. The bed was seen with clinkers. This further reduced the bed steam generation capacity and increases the superheating capacity of the boiler.

The Oxygen levels were too high. Under this condition, the flue gas produced will be more and thus convection SH heat pick up will be high, resulting in high steam temperature. It is seen that the DP drop was as high as 330 mmWC. This is just more than the MCR DP drop.

PSH outlet steam temperature is seen to be 470-475 deg C. The design temperature is 421 deg C at PSH outlet.

The main steam pressure had been around 80 kg/cm2, during the activation of the 3rd compartment.

The ID fan draft had been at 150 mmWC during this time. The ID fan is selected for 195 mmWC with a discharge side pressure of 27 mmWC. The Oxygen level was at 12.7% as informed by the plant engineers. This O2 level corresponds to 200% EA. The flue gas quantity is about 51.28 m3/s. This matches with the operating point at the fan performance curve.

Boiler configuration & Superheater steam temperature

The boiler is complete convection superheater. The start up compartment and 2nd compartment are below the nose panel. The flue gas thus will travel towards PSH without filling the cavity above the SSH. Even otherwise the waterwall heat transfer area is covered with refractory. This boiler by configuration will have high SH temperature at the time of compartment transfer. Even before completely activating the 3rd compartment, the flue gas generated from overbed particle combustion will shoot up the PSH outlet temperature and SSH outlet temperature. This is similar to case in a Thermax boiler wherein the start up burner was placed below the nose panel. It resulted in overheating failure of SSH bends. See the comparison of the boiler configurations in photo 1 & 2 of annexure 1.2.

The remedy to control the steam temperature is to reduce the boiler operating pressure to a minimum permissible pressure as per turbine maker. This has to be done by opening the start up vent more. Then the margin between the main steam temperature and saturation temperature will increase. Also the flash steam produced due to pressure drop, will generate additional steam.

It is necessary to establish high bed temperatures and uniform bed temperatures in the start up compartments, so that the steam generation by the bed coils is available to control the steam temperature. It is seen that the bed temperatures were less than 750 deg C also in the 2nd

compartment, during which the activation of 3rd compartment was attempted. In addition the bed temperatures were not uniform indicating the 2nd compartment was not stabilised.

It is required to have a minimum bed height of 400 mm in 1st and 2nd compartment before attempting to activate the 3rd compartment. This will help in achieving easy activation of the bed.

The border between the 2nd compartment and 3rd compartment shall be 600 mm tall from nozzle. The 3rd compartment material height shall be 300 mm only and not more.

The bed temperatures in 1st and 2nd compartments should be 850 900 deg C before attempting transfer.

The higher bed size had given more trouble in compartment transfer. Has the boiler been provided with 5 compartments, there would have been fewer problems with respect to steam temperature? The transfer would have been very comfortable.

Erratic bed temperature and improper fluidisation

The boiler is designed for overbed and underbed feeding arrangements. Thus the SA is sized for supplying 10-15% overfire air. Such as normally 10% air may be admitted to achieve good particle combustion / less LOI. This boiler is designed with high pressure drop DP nozzles. With 10% overfire air, the DP drop is expected to be 290 mmWC. When the MCR DP drop is 290 mmWC, the DP drop in minimum fluidisation condition (MFC) will be 494 mmWC (35 deg C air temperature) for the 2353 GCV coal. The design closely follows the overbed design given to ITC Bhadrachalam.

In order to mix the bed of say 300 mm bed height (above the air nozzle), the DP drop will be as below:

Air temperature to DP

35 deg C 100 deg C 125 deg C 150 deg C 175 deg C 195 deg C

DP drop for MFC

494 mmWC

408 mmWC

382 mmWC

359 mmWC

340 mmWC

325 mmWC

At cold condition, the DP drop will be 494 mmWC for minimum fluidisation velocity of 0.8 m/s. It means the particle size for start up should be below 2 mm and above 0.5 mm. If bed ash is used as bed material there will be fluidisation problem. The bed will not activate at all. If the air temperature is say 125 deg C when 1st and 2nd compartments are running, the third compartment will need 382 (DP drop) + 300 mmWC (bed ht) = 682 mmWC to thoroughly fluidise the bed.

The above chart is applicable for any compartment operation, during start up times, that is when the bed height is around 300 mm.

Steam generation ,

TPH 72 70 65 60 55 50 45 40 35 30 25 20Air flow, TPH 89 86.5 82.6 76.3 69.9 63.6 57.2 50.9 44.5 38.1 31.8 25.4

The air flow for 20% EA level at various loads will be as above. There can be variation of +10% due to low bed height during start up times. The above are air flow requirements for 2353 GCV coal. For higher grade coal, the air flow will be slightly less due to improved efficiency.

Once the bed is at rated bed temperature, say 900 deg C, the generation is derated to 65% in a bed. This will correspond to a DP drop of 127 mmWC and a fluidisation velocity of 1.8 m/s. It is like the entire bed can be used for steam generation of 46 TPH. The SA needs to be closed for this condition so that all the air is admitted at air nozzles.

But to achieve the 900 deg C, the bed height has to be reduced and / or bed coil heating surface has to be reduced. This will be known once all the compartments are to be put in to operation.

The PA flow (with a design velocity of 14 m/s), will be 14.5 TPH for all compartment operation, when the air temperature is 125 deg C. We can say per feeder around 3 TPH air should be OK. However PA flow should be optimised for a minimum suction at mixing nozzle.

During 1st compartment / 2nd compartment operation, the DP drop should be 150 200 mmWC. Excess to this will lead to high spillage to the next compartment.

ID fan sizing

During the operation on 25th and 26th Jan 2014, the ID fan draft had been maximum -150 mmWC. The Oxygen was reported to be 11.5 % at APH outlet. The feedwater temperature was initially at room temperature. Later it was raised to 120 deg C. When the feed water temperature is too low, the bed evaporators have to do the job of sensible heat as well as latent heat. Thus the steam generation rate at bed coil is less. The heat duty of the boiler increases at lower feed water temperature. It is seen by calculations that the gas flow would be around 50 m3/s at ID inlet. There is no shortage of fan capacity. In case there was a high draft loss anywhere in the flue gas circuit, then we can say the ID fan does not have capacity. As such the draft at ESP outlet was less as compared to design head of 195 mmWC. This is the draft generated at the ID fan suction with a discharge pressure of 26 mmWC. The fan sizing calculations were done and it was found that the fan sizing is OK. The calculation sheet is attached in annexure 1.3.

Chimney sizing

The gas velocity inside chimney at 20% EA for 2353 GCV coal with 82% efficiency and at 135 deg C, will be 19.4 m/s. The draft at the base of the chimney will be 1.8 mmWC. See calculation attached in annexure 1.4. This is without considering the entry loss, exit loss and transition losses at every transition inside the chimney. It is likely to be around 15 mmWC. Already 26 mmWC back pressure is considered in ID fan selection. There is always high turbulence in RCC chimney because it is made cylindrical from bottom to top unlike steel chimney where the base dia is quite large. Localised turbulence persists at chimney base. The +ve pressure is seen in many RCC chimney. The gas smell will be felt at the vent holes provided in RCC shell.

Flue gas duct sizing between the APH and ESP

The air and gas calculations were done for the design coal 2353 kcal/kg GCV. It is seen that the gas velocity at the APH outlet duct will be 12.2 m/s. The duct size of 1848 mm ID is quite suitable for the boiler. There is no under-sizing of the duct. The duct velocities are presented photo 5 in annexure 1.2.

Desuperheater sizing

The superheater surfacing is seen to be OK. The heat transfer areas of SSH, PSH B and PSH A are found to be in order. The spray water temperature is assumed to be 204 deg C by us. In annexure 1.5, the predicted performance of SH (for the design coal 2353 kcal/kg) is given. It is seen the spray water temperature will be 140 deg C as per the scheme here.

The spray water flow required with 204 deg C water will be 2530 kg/h. The control valve is sized for 4.48 TPH at 88% valve opening. The spray water line size is 33.4 x 4 mm. The line velocity at 4.48 TPH will be 2.46 m/s. The line velocity can be up to 3 m/s. There is no under-sizing of the valve.

The refractory removal done in the waterwall after the SSH will lower the steam temperature at a load of 72 TPH. Since the plant load is expected to be around 50 TPH, the refractory removal will not affect the steam temperature.

It is seen that the PSH B outlet piping is selected to be P11 material. The PSH B coil material is T11 material at the hot end. The coil and piping can withstand a service temperature of 485 deg C as per code formulae. Code has its safety margin. See the calculation attached in annexure 1.6.

High Oxygen level in flue gas during the commissioning trials

The high oxygen level can be due to passing of air in the non-operating compartment. The wind box pressure data was not available for the 3rd compartment in 25th / 26th January logsheet. In a non-operating compartment there can be leakages due to damper problem.

The DP drop in the 1st and 2nd compartment had been as high as 300 mmWC. This is just about the full load DP drop. If the coal was fed more the steam generation would have simply touched 72 TPH.

All the compartment dampers were checked. In the 3rd compartment, in the upper left corner (as viewed from windbox side), there is a metal to metal contact instead of seal to metal contact. Otherwise the construction of the damper is quite good and well thought of. It is advised to operate the PA flow as optimum as possible. The PA flow in idle compartment can be substantial. It is advised to keep it closed till the 3rd compartment is activated. It is advisable to keep the PA header pressure as minimum as possible.

Burner air flow should be reduced to a minimum. It may be necessary to have air register pressure of say 25 mmWC only.

The SA flow and spreader air flow should be in fully closed condition till the combustor operation is stabilised. SA is required based on CO and LOI levels only. It can be used only for full load operation. Under low load operation, any air above the bed will reduce the DP pressure drop and may cause defluidization. This is not advisable.

The power cylinder pressure can be increased to 5 kg/cm2 in order to exert more thrust for damper closing. In case the power cylinder is unable to give a positive seal, manually the damper shall be closed by the screw wheel operating arrangement.

Conclusion

The various reasons discussed above points out to two causes.

First cause is the operational procedures required for this boiler configuration. This included improper stabilisation of 1st and 2nd compartment operation. The DP values must be known to

operators so that they operate based on allowable minimum and maximum DP drop for operation. Similarly MFC DP drop should be known to them to enable proper mixing while starting a cold bed.

Boiler configuration calls for additional care in operation. The operational tips are covered in the discussions above.

The boiler should be started with fresh bed material or sieved bed material to size range of 0.5 to 2 mm size shall be used. If used material is tried the fluidisation will be problem during start up. It is advised to procure a rotary screen for regular screening of bed ash and for keeping a stock for two start ups. See the photo 6 in annexure 1.2.

The combustion calculations are made for the performance coal and are presented in annexure 1.7. It is seen that the bed coil heat transfer area is on the higher side. In order to operate at rated bed height of 900 mm and at 925 deg C, part of the coils are to be covered with refractory so that the heat pick up by bed coil will be reduced. Each outer coil will have to be covered to length of 1.18 m. As the coal grade is increased, the operating bed height will increase as the heat taken out by the ash and moisture would come down.

DERATING THE BOILER FOR PRESENT LOAD CONDITIONS IN THE PLANT

It was learnt that the boiler was purchased for a higher capacity considering the future requirement. The present load would be in the range of 36 TPH to 50 TPH only. This calls for certain changes in the combustor for smooth operation of the boiler. This is particularly related to clinker free operation, less loss on ignition in the ash, limited spray in DESH and flexibility to handle sudden load changes.

The following are some of the points to be discussed with OEM in order to make the boiler suitable for the above requirements.

Combustor modification for 50 TPH peak capacity

In the combustor design, the bed coil HTA plays a major role. Once the bed coil HTA is decided, for 72 TPH, entire bed operation for 50 TPH would result in low bed temperature / low bed height. The fluidisation velocity also will come down. For the present combustor cross section area, the fluidisation velocity will be 2.8 m/s with the bed temperature of 920 deg C. At 50 TPH load, the fluidisation velocity will be 1.98 m/s if the bed temperature can be maintained at 900 deg C.

The bed temperature can be improved if only parts of the bed coils are made ineffective. This is generally done by covering the longer bed coils with phoscast refractory (phosphate bonded high alumina castable). The studs provided at the bottom part of the bed coils work as anchors to support the refractory. It will be necessary to cover nearly 1.6 m length of the outer bed coil in all 150 coils to have an operating bed height of 800 mm. If we need to have a 900 mm operating height, the coils have to be covered up to 2.2 m. The present effective length of the outer bed coil is seen to be 3.48 m and the length of the inner coil is 1.63 m. See layout in photo 6 of annexure 2. It is possible to operate all the compartments with a height of 700 mm. This carries a risk of ash accumulation when a compartment is slumped. See work sheet attached in annexure 2.

The refractory cover is any how required at the bed coil bends where the studs are pitched at 40 mm. See photographs 1 to 3 in annexure 2. Balance refractory cover can be preferably done above coal nozzle area so that erosion above bed coil can be kept under control. See photo 4. See a typical drawing made by us in photo 5 & 6 for another boiler.

Since the boiler is under warranty period, it is recommended to take up with OEM for details of refractory lining and the methodology of derating. The phoscast lining was done in OEMs boiler in their installations at SPB and JSW.

The phoscast is a product developed by Castwell industries, Nagpur. The specification by the supplier is attached in annexure 3. There are equivalent products such ACC-plast and Tataplast. But phoscast is found to go well. The application should be done by the suppliers mason. The profile of phoscast is very important. The castable should not project out of the tips of studs. See drawing in photo 5 of annexure 2.

The DP drop at 50 TPH steam generation is calculated to be 155 mmWC. This is quite good as compared to DP of 86 mmWC being operated in many Cethar boilers. This is with SA ports closed, so that all the combustion air is given at the nozzles in the DP.

By the above modifications, the boiler can be derated to a peak capacity of 50 TPH. Further by operating at 950 deg C, peaking situations can be made. With excess air further small peaking capacity will increase. It will at least have 55 TPH peaking capacity.

By doing the above, all the evaporative circuits come in to good circulation on the water side. That is a must for proper water chemistry.

It is also possible to blank some of the coils at the header and adjust the heating surface as required.

Flexibility for load turndown

The boiler is provided with one small compartment and two bigger compartments. This cuts down the flexibility of load control. If load turn down is expected to be frequent, the number of compartments has to be made as five. Without which, there will be venting losses, which will make the boiler inefficient.

It should be possible to achieve further turn down by slumping the first compartment. 36 TPH steam generation should be possible after the above modification is done. Operating with 1 & 2 compartments and meeting the steam requirement would put the third compartment coils in caustic gouging regime.

The main steam temperature profile will not be a problem. Refractory on waterwall can be further adjusted to achieve less spray or zero spray at 36 TPH load. It must be remembered that the idle compartment should be activated once in 4 hrs to avoid concentration of phosphate chemical in the idle coils. Caustic gouging is experienced in idle bed coils.

BOILER OPERATION ON 2ND FEBRUARY 2014

The report below is about changes made in boiler light up and operations on 2nd February 2014. The snapshots of DCS on 24th January and on 2nd February are enclosed in annexure 4.

1. After the design check it was understood that the bed cold fluidisation would be difficult. Hence the bed material was emptied completely as per our request. New material was added. While draining the bed, clinkers were found in the bed.

2. The bed height recommended was 300 mm above the air nozzle. In addition as requested bed material was poured along the borders to control the spillage during mixing of the bed.

3. Boiler was started on 1st Feb evening and 2nd compartment activation could be done only on 2nd morning. 2nd compartment activation was done in our presence. The air box pressure and bed height difference was maintained in the range of 300 mmWC by OEM operators. They were convinced to keep the air flow such that the DP drop would be in the range of 150 mm WC to 200 mmWC. After this the steam temperature before DESH came under control. ID fan loading was normal.

4. The bed height was increased to 380 mm when the1st and 2nd compartments were in operation. This proved better stability.

5. There was an earth fault trip in the transformer. The beds were revived with underbed feeding, though OEM operators were interested in overbed.

6. The PA line choking wax experienced once the PA header pressure came down to 850 mmWC when the PA lines of 3rd compartments were opened for line flushing. This made few lines to get choked. The PA lines were being dechoked without closing the coal feed gates above. This resulted in low bed temperatures. On request, the gates were closed and the line dechoking was done. This had helped in maintaining the bed temperature as the coal was not spilling in to the working PA lines to the bed.

7. The 3rd compartment mixing was found to occur only at 650 mmWC airbox pressure. The mixing was done several times before coal feeding.

8. As the 3rd bed was catching up with coal feed, the steam temperatures started crossing 530 deg C. As per instruction, the boiler steam pressure was lowered to 78 kg/cm2 before activating 3rd compartment. The steep temperature rise is due to large sized bed activation. As the bed temperature showed rising trend, the 1st compartment was slumped. The bypass of DESH spray had to be opened. The surge in steam temperature is due to activation of a large size compartment.

9. The steam requirement did not go up further as there was an exhaust temperature issue in turbine, once the LP extraction flow was increased. Instructions were given to OEM operators to hold the bed height at 375 mmWC so that the bed temperatures are around 850 deg C only. Only 2nd and 3rd compartments are to be operated. However, once in a hour or two, the 1st compartment must be activated for creating circulation. The DP drop should be 175 mmWC.

10. The water chemistry needs to be taken care of. The PO4 levels have to be in the range of 2-4 ppm. The TSP and DSP are to be mixed at 70:30 ratio and used for this pressure to avoid caustic gouging.

The boiler had to be run on low bed height as predicted. On refractory lining of bed coils, it would be possible to keep all the beds in operation for a load of 50 TPH. DP drop would be 155 mmWC.

K.K.Parthiban

ANNEXURE 1.1 REVIEW OF LOG SHEETS

Photo 1: The bed temperatures are seen to be erratic. Some of the bed temperatures are too low. With this condition, the third compartment activation was not successful.

Photo 2: The DP drop is as high as 300 mmWC. This high DP will throw the bed material to non operating compartment. Further it cools the bed. The less bed DP indicates that the bed height is less. The bed height shall be increased while 1st and 2nd compartments are in operation.

Photo 3: The PSH outlet steam temperature has touched 480 deg C, where as the thickness and material selection is based on 421 deg C.

Photo 4: The ID draft had been at 150 mmWC. The ID fan is selected with 195 mmWC. The gas flow had been high as indicated by the oxygen level.

ANNEXURE 1.2- PHOTOGRAPHS

Photo 1: The photo above shows the boiler configuration at this plant. The burner and start up compartments are located below the nose. This boiler will have high PSH outlet temperature during start up than expected. Once all the compartments are put in to operation there is no problem.

Photo 02: The above is a boiler by Thermax which also had a problem of steam temperature excursion and resulted in repeated failure of SSH bottom bends. When start up compartment is located below the nose panel, the cavity in front of SH is not used up in cooling the flue gas. In this boiler the steam pressure was purposely brought down before activation of 2nd compartment. Steam generation was increased by increasing the bed height in the start up compartment before attempting second compartment activation.

Photo 03: The gas flow is estimated to be 51.92 m3/s with 12.7% O2 at boiler outlet. This is the condition when the boiler was generating 45 TPH steam with a feed water temperature of 130 deg C.

Photo 04: The fan performance curve says that the fan can handle 52 m3/s at 150 mm draft.

Photo 05: The gas velocity is seen to be OK at APH to ESP duct. There are no bottle necks anywhere in the gas ducting. This is for the performance coal of 2353 Kcal/kg GCV.

Photo 06: It is advised to procure a rotary screen as shown above for regular screening and reuse of bed ash as bed material. The front section of the screen is of 0.5 mm opening and the rear has to be of 2 mm.

ANNEXURE 1.3: FAN SIZING FOR PERFORMANCE COAL AT 72 TPH STEAM GENERATION

FAN SIZING CALCULATION Date & time:PROJECT : INPUTS FOR FAN SIZING CALCULATIONS

Site elevation = 27 metresGas temp at Airheater outlet = 140 deg C

Air temp at Airheater air inlet = 35 deg CAirheater outlet = 195 deg C

Design air velocity in fuel piping = 14 m/s

Fan detailsNo of PA lines per compartment = 25

FD fan capacity (% MCR ) = 100 %FD fan efficiency = 85 %

ID fan capacity (% MCR) = 100 %ID fan efficiency = 75 %

PA fan capacity (% MCR ) = 100 %PA fan efficiency = 75 %

FD fan design head = 1205 mmwcPA fan design head = 676 mmwcID fan design head = 221 mmwc

Flue gas generated per kg of fuel = 4.354 kg/kgMolecular wt of flue gas = 29.01

Wet air required per kg of fuel = 3.863 kg/kgFuel Feed Rate = 23,043 kg/h

Margin on FD fan flow = 20 %Margin on PA fan flow = 20 %Margin on ID fan flow = 20 %

FAN SIZING CALCULATIONSCalculations of volumetric gas flow rate

Wet flue gas produced per kg of fuel = 4.354 kg/kgFuel burnt rate = 23,043 kg/h

Wet flue gas flow rate = 4.354 x 23,043 kg/h = 100329.22 kg/h

Molecular wt of flue gas = 29.01 from air & gas calcK, altitude correction factor = 0.997

Flue Gas volume flow rate at 0 deg C = 100329.22 x 22.4 / ( 29.01 x 0.997 ) = 77,702.07 Nm3 /hr

Flue Gas volume flow rate at 0 deg C = 21.58 Nm3 / secBoiler exit temperature, deg C = 140 Deg C

ITC tribeni performance coal2/1/14 4:37 PM

Gas flow at boiler exit temperature = ( 21.58x ( 273 + 140 ) / 273 )m3 /sec = 32.65 m3 /sec

Calculations of volumetric Air flow rate

Wet air required per kg of fuel = 3.863 kg/kgFuel firing rate = 23,043 kg/h

Wet air flow rate = 3.863 x 23,043 kg/h = 89015.11 kg/h

Molecular wt of wet air = 28.36K, Altidue correction factor = 0.997

Wet air volume flow rate at 0 deg C = 89015.11 x 22.4 / ( 28.36 x 0.997) = 70,519.69 Nm3 /hr

Wet air volume flow rate at 0 deg C = 19.59 Nm3 / secAir temp at Airheater air inlet = 35 Deg C

Hence, Volumetric Air flow rate = ( 21.58x ( 273 + 35 ) / 273 )m3 /secVolumetric air flow rate = 22.10 m3 /sec

Estimation of Fuel transport air flowTotal no of Fuel lines = 25

Normal Fuel flow per line = ( 23,043 / 25) = 922Fuel Flow w/o one Feeder = ( 23,043 / 125) = 184.34

Selected fuel line size, mm Nb, 100 / 125 / 150 = 130Design air velocity in fuel piping = 14 m/s

Total Fuel air flow rate = 25 x 3.1416 x (130/2000)^2 x 14 m3/sTotal Fuel air flow rate = 4.646 m3/sAir outlet Temperature = 125 Deg C

Total Fuel air Volume flow rate = ( 4.646x 273 / ( 273 + 125 ) )m3 /sec = 3.19 Nm3/s

Total Fuel air flow rate = 3.19 x ( 28.36 x 0.997) x 3600 / 22.4 = 14,495.95 kg/h

FAN SIZING CALCULATIONS

FD fan sizing FD fan capacity (% MCR ) = 100 %

MCR airflow required for combustion = 22.10 m3/s MCR airflow of FD fan = ( 22.10x 100 / 100 ) m3/sMCR airflow of FD fan = 22.1 m3/sMargin on FD fan flow = 20 %

Design Flow for FD fan = 22.1 x ( 100 +20 ) / 100 m3/s = 26.52 m3/s

FD fan Design head = 1205 mmwcAssumed FD fan efficiency = 85 %

FD fan operating power required = 100 x 26.52 x 1205/ ( 101 x 85 ) kw

= 372.2 kwMinimum motor power required = 1.1 x 372.2 kw

Minimum motor power required for FD fan = 409.4 kw

PA fan sizing PA fan capacity (% MCR ) = 100 %

MCR fuel transport airflow required = 4.646 m3/s MCR airflow of PA fan = ( 4.646x 100 / 100 ) m3/sMCR airflow of PA fan = 4.646 m3/sMargin on PA fan flow = 20 %

Design Flow for PA fan = 4.646 x ( 100 +20 ) / 100 m3/s = 5.58 m3/s

PA fan Design head = 676 mmwcAssumed PA fan efficiency = 75 %

PA fan operating power required = 100 x 5.58 x 676/ ( 101 x 75 ) kw = 49.8 kw

Minimum motor power required = 1.1 x 49.8 kwMinimum motor power required for PA fan = 54.8 kw

ID fan sizing ID fan capacity (% MCR ) = 100 %

MCR gas flow produced = 32.65 m3/s MCR gas flow of ID fan = ( 32.65x 100 / 100 ) m3/sMCR gas flow of ID fan = 32.65 m3/s

Margin on ID fan flow = 20 %Design Flow for ID fan = 32.65 x ( 100 +20 ) / 100 m3/s

= 39.18 m3/sID fan Design head = 221 mmwc

Assumed ID fan efficiency = 75 %ID fan operating power required = 100 x 39.18 x 221/ ( 101 x 75 ) kw

= 114.3 kwMinimum motor power required = 1.1 x 114.3 kw

Minimum motor power required for ID fan = 125.7 kw

Results summaryFD fan PA fan ID fanreqd supply reqd supply reqd supply

m3/s 26.52 26.13 5.58 5.53 39.18 42.93mmwc 1205 1205 676 676 221 221Deg C 35 195 195 195% 85 75 75kw 372.2 49.8 114.3kw 409.4 54.8 125.7kw 400 400 75 90 132 132Selected motor Kw

Design flowDesign head

Design temperatureAssumed effciency

Operating powerMin motor power

ANNEXURE 1.4: DRAFT GENERATED AT CHIMNEY BASE

ENWS-230-00

Client

DateName NameSign Sign

Rev Nr. Rev by Checked Date

Total Height of the chimney , H = 67 m 219.81628 ftInternal diameter of the chimney at top, D = 1.45 m 57.086645 inch

Density of air at atmospheric temperature , wa = 1.0545 Kg/m3 0.06583033 lb/cftGas density at mean temp, wg = 0.8555 Kg/m3 0.05340715 lb/cft

Acceleration due to gravity , g = 9.81 m/s2

Draft Generated at chimney base = (H x (wa-wg))*12/62.4 inWC= inWC= mmWC

Draft generated at the base of the chimney = 13.339 mmWC

W, gas fllow = 103626 kg/h 228455.952 lb/h

Venus Energy Audit System

WO / Prop.Nr

K.K.Parthiban

Document noITC TRIBENI xxx

DRAFT GENERATED AT CHIMNEY BASEPrepared By Approved By

VENUS ENERGY AUDIT SYSTEM

INPUT:

31-Jan-14

Revision Details

13.3390.525

CALCULATION:

v, sp volume = 1.1689071 m3/kgQ, gas flow = 33.6 m3/s

Flow area = 1.7 m2V, velocity = 20.4 m/s

D, Stack dia = 1.45 m , Viscosity of flue gas = 0.0783 kg/mh

= 2.175E-05 kg/ms Reynolds number = 1162115

f, friction factor = 0.02G, mass flux = 17.431724 kg/m2s

Draft loss = 16.730 kg/m2

= 16.730 mmWC

= + 3.4 mmWC ( 9 transitions)Draft at Chimney base ( w/o considering entry & exit loss & expn loss at each transition

OUTPUT:

Sheet 1 of 2

ENWS-230-00

Sheet 2 of 2

ANNEXURE 1.5: THERMAL PERFORMANCE OF THE SUPERHEATERS

SUPER HEATER PERFORMANCE CHECK

SSH PERFORMANCE

The gas flow is with 20% EA for the design coal. FEGT is with the assumption that the bed temperature will be at 925 deg C.

PSH B performance

The spray requirement will be only 2530 kg/h. The gas temperature at PSH B inlet is taken with a cavity drop of 20 deg C as the waterwall is refractory lined.

PSH A performance

The cavity temperature drop is taken as 10 deg C as the side waterwalls are exposed. The superheater surfacing is adequate for 72 TPH steam generation. There was no need for altering the refractory lining in the waterwall above SSH.

ANNEXURE 1.6: STRENGTH CALCULATIONS FOR PSH-B TUBE AND PSH B OUTLET PIPING

Wp = 2 f ( T - C ) Regulation : IBR 338 (a)D - T + C

Where ,

Wp = Working pressure , Kg / cm2

f = Allowable Stress , Kg / cm2 neg. tolerance

t = minimum thickness of Tube , ( nom. Thk - neg. tolerance ), mm = 12.5% for BS 3059 PII

D = External diameter of tube , mm = 7.5 % for BS 3059 PI (ERW Gr. 320)

P = Design pressure = 104 Kg / cm2 = 0.0 % for SA 213 T11, T22

C = 0.75 for pressure upto 70 kg/cm2 ; 0 for pressure above 70 kg/cm2

D thk1 44.5 4.00 4.00 SA 213 T11 525 520.50 100.95 > 104 Kg / cm2

2 44.5 4.00 4.00 SA 213 T11 520 572.47 111.02 > 104 Kg / cm2

Wp = 2 f E ( T - C ) Regulation : IBR 350 ( Eqn. 91 )D - T + C

Where ,

Wp = Working pressure , Kg / cm2

f = Allowable Stress , Kg / cm2 neg. tolerance

t = minimum thickness of Pipe , ( nom. Thk - neg. tolerance ), mm = 12.5%

D = External diameter of pipe , mm

P = Design pressure = 104 Kg / cm2 E = 1 for Seamless pipe

C = 0.75

D thk1 219.1 15.09 13.20 SA 335 P11 500 782.13 94.27 > 104 Kg / cm2

219.1 15.09 13.20 SA 335 P11 485 892.25 107.54 > 104 Kg / cm2

IBR calculation for tubes

IBR calculation for pipes

Metal temp

Link pipe between PSH outlet to SSH inlet

Working Pressure,

Wp, Kg / cm2

tube Size , mm

Material

MaterialAllowable Stress,

f , Kg / cm2

Working Pressure,

Wp, Kg / cm2

Metal temp

PSH 1B tubes

Thk, less neg. Tol,

t

Allowable Stress,

f , Kg / cm2 Description

Thk, less neg. Tol,

t

Sr. No Description

Sr. No

PSH 1B tubes

Pipe Size , mm

ANNEXURE 1.7: COMBUSTION CALCULATIONS FOR 72 TPH WITH PERFORMANCE COAL

PROJECT : INPUTS FOR COMBUSTION CALCULATIONSAIR & GAS CALCULATIONS

Ta Ambient temperature 35 Deg CP1 Relative humidity 60 % assumedMa Moisture in dry air ( from tables) 0.02825 kg/kgE Excess air 20 %Te Boiler outlet gas temperature 140 Deg CEl Site elevation 27 MetresP Flue gas pressure 5 mmwc

Constituents of fuelFUEL

C Carbon 26.67 % by wtH Hydrogen 1.62 % by wtO Oxygen 8.70 % by wtS Sulphur 0.38 % by wtN Nitrogen 0.94 % by wtM Moisture 12.00 % by wtA Ash 49.70 % by wt

100.01GCV Gross GCV of fuel 2353.00 Kcal /kg

INPUTS FOR EFFICIENCY CALCULATIONS

LOI unburnt Carbon in fly ash 2.5 %HLS1 Carbon loss =(LOI/(100-LOI)* Ash%*8050/GCV

4.36

HLS1 Carbon loss ( assumed ) 4 %HLS6 Radiation loss ( assumed ) 0.3 %HLS7 Manufacturer margin (assumed ) 0 %

LocationsA1 % Ash collection at location 1 Bed 15 %A2 % Ash collection at location 2 Bank 0 %A3 % Ash collection at location 3 Economiser 5 %A4 % Ash collection at location 4 Airheater 5 %A5 % Ash collection at location 5 MDC 0 %A6 % Ash collection at location 6 ESP 75 %

100T1 Temperature of ash at location1 850 Deg CT2 Temperature of ash at location2 300 Deg CT3 Temperature of ash at location3 250 Deg CT4 Temperature of ash at location4 150 Deg CT5 Temperature of ash at location5 150 Deg CT6 Temperature of ash at location6 150 Deg C

INPUTS FOR BOILER DUTY CALCULATIONS

Steam generation rate Nett 72000 Kg/hMain steam pressure 86 kg/cm2 gMain steam temperature 520 Deg CFeed water inlet temperature 204.4 Deg CSuperheater Pressure drop 5 kg/cm2 gSaturated steam flow from drum 0 kg/h

ITC tribeni performance coal

Performance coal

Boiler efficiency Calculated 82.71Boiler efficiency selected 82 %

INPUTS FOR AIR,GAS DUCT,CHIMNEY SIZING CALCULATIONS

Flue gas ducting Gas tempSH outlet 500 Deg CEconomiser outlet 270 Deg CAirheater outlet 140 Deg CAir ducting Air tempAirheater outlet 195 Deg CDesign velocitiesDesign velocity in gas duct 16 m/sChimney design gas velocity 15 m/sDesign velocity in air duct 10 m/s

INPUTS FOR FAN SIZING CALCULATIONS

Design air velocity in fuel piping 14 m/s

No of PA lines 25Fan sizing FD fan capacity (% MCR ) 100 %FD fan efficency 85 %ID fan capacity (% MCR) 100 %ID fan efficency 75 %PA fan capacity (% MCR ) 100 %PA fan efficiency 75 %

FD fan design head 1205 mmwcPA fan design head 676 mmwcID fan design head 221 mmwc Margin on FD fan flow 20 %Margin on PA fan flow 20 %Margin on ID fan flow 20 %

INPUTS FOR FLUIDISED BED SIZING CALCULATIONS

Design bed temperature = 925 Deg C

DateName NameSign Sign

Rev Rev by Checked Date

= 26.67 Min Max= 1.62 318 327= 0.38 284 301= 49.70 314 318= 8.70 331 348= 0.94 327 333= 2,353.00 329 335= 2353 325 333

325 327322 325327 338338 349301 312305 314268 301

=

==

HHV, Kcal/ kg =

=

==

HHV, Kcal/ kg =

Kg air / GJ = = { (1+0.013)*(11.5095*C + 34.283* ( H2-O2/8)+ 4.3102 *S) / HHV } * 10^4 Kg air / GJ = {(1+0.013)*(11.5095*26.67+ 34.283*(1.62-8.70/8)+ 4.3102 *0.38) / 2,353.00}*10^4 /100 Kg air / GJ = 336.0745

HHV, MJ/kgGCV verification by Dulong formula - For Bituminous and anthracite coals only

WoodSoftwood, peathard wood

Bagasse

33.96*C + 144.213 * (H2 - O2 / 8 ) + 9.42* S

For other fuels and coal, theortical air shall be calculated and compared with the values in table 1. If the air required does not match correct GCV

2355.2

( 34.094* 26.67+132.298* 1.62+6.838 *0.38-1.531* 49.70-11.986 ( 8.70+ 0.94))/1009.35

9.8609

2233.2

34.094*C + 132.298* H + 6.838 * S- 1.531 A - 11.986 ( O + N )where C, H, O , A , N and S are weight fractions

GCV verification by IGT formula - For subbituminous and lignite onlyHHV, MJ/kg

where C, H, O and S are weight fractions(33.96 * 26.67 + 144.213 * ( 1.62 - 8.70 / 8 ) + 9.42 * 0.38)/100

Oxygen

US coals

AnthraciteNitrogen Low vol bituminous

HHV Dry Med vol bituminous

LigniteFluidDelayed

High vol bituminoussub bituminous

% by wtKcal / kg

Sulphur Coke oven gasAsh Natural gas

% by wt

% by wt% by wt

Kcal / kg

Coke

HHV reported

Hydrogen Oil fuels

WO / Prop.Nr

Revision Details

% by wt% by wt

INPUTS Therotical air required for fuelsDry coal

Carbon

Document no

GCV check for fuels from Ultimate analysisPrepared By Approved By

Client Dalmia cements WXXX-XX-DCS-XXX-XX

Table of air qty / fuel kg air / GJ

COMBUSTION CALCULATIONS FOR FUEL PER KG BASIS Date & time: 2/1/14 5:39 PMPROJECT :

INPUTS FOR AIR & GAS CALCULATIONS Performance coal

Ta, Ambient temperature = 35 deg C P1, Relative humidity = 60 % Ma, Moisture in dry air = 0.02825 kg / kg

E, Excess air = 20 % Constituents of fuel ( % by weight )

C, Carbon = 26.67 % Carbon lost in ash = 1.169 %

carbon burnt = 25.501 % H, Hydrogen = 1.62 %

O, Oxygen = 8.7 % S, Sulphur = 0.38 %

N, Nitrogen = 0.94 % M, Moisture = 12 %

A, Ash = 49.7 %

Air requirement calculationsO2 reqd, kg/kg of Carbon in fuel = 2.644 kg/kg

O2 reqd, kg/kg of Hydrogen in fuel = 7.937 kg/kg O2 reqd, kg/kg of Sulphur in fuel = 0.998 kg/kg

Solid crbon unburnt from Efficiency calc, = 0.012 kg/kg O2 reqd, for the Carbon in fuel =( 0.2667-0.012)x2.644 /100) kg/kg

= 0.674 kg/kg O2 reqd, for the Hydrogen in fuel =( 7.937x1.62 /100) kg/kg

= 0.129 kg/kg O2 reqd, for the Sulphur in fuel =( 0.998x0.38 /100) kg/kg

= 0.004 kg/kg Stochiometric O2 reqd / kg of fuel = O2 reqd for C,H,S in fuel - O2 in fuel) kg/kgStochiometric O2 reqd / kg of fuel = ( 0.674+0.129+0.004) -(8.7 / 100) kg/kg

= 0.72 kg /kg of fuel Excess O2 required / kg of fuel = ( 0.72x / 100 ) kg /kg of fuel

= ( 0.72x 20 / 100 ) kg /kg of fuel = 0.144 kg/kg

Total O2 required / kg of fuel = ( 0.72+ 0.144) kg/kg = 0.864 kg/kg

Weight fraction of O2 in atmospheric air = 0.23 kg/kg Dry air required for Combustion, kg/kg of fuel =( 0.864/ 0.23) kg/kg

= 3.757 kg/kg Due to relative Humidity, wet air reqd, kg/kg of fuel =( 1 + 0.02825) x 3.757) kg/kg

Wet air required, kg /kg of fuel fired = 3.863 kg/kg Dry air required, kg /kg of fuel fired = 3.757 kg/kg

ITC tribeni performance coal

Gas weight constituents calculations

CO2 produced, kg/kg of Carbon in fuel = 3.644 kg/kg H2O produced, kg/kg of Hydrogen in fuel = 8.937 kg/kg

SO2 produced, kg/kg of Sulphur in fuel = 1.998 kg/kg

CO2 produced, for the Carbon in fuel =( 3.644x26.67 /100) kg/kg = 0.929 kg/kg

H2O produced, for the Hydrogen in fuel =( 8.937x1.62 /100) kg/kg = 0.145 kg/kg

H2O in combustion air = 0.02825x3.757 kg/kg = 0.106 kg/kg

H2O due to moisture in fuel = 12/100 kg/kg = 0.12 kg/kg

H2O due to air & H2 combustion& fuel moisture =( 0.106+0.145+0.12) kg/kg = 0.371 kg/kg

SO2 produced, for the Sulphur in fuel =( 1.998x0.38 /100) kg/kg = 0.008 kg/kg

O2 in flue gas ( Excess O2 added ) = 0.144 kg/kg

N21,Nitrogen due to fuel = N kg/kg = 0.0094 kg/kg

Weight fraction of Nitrogen in Dry Air = 0.77 kg/kg N22 due to Air, kg per kg of fuel = 0.77 x 3.757 kg/kg

= 2.893 kg/kg Total N2 in flue gas , kg/kg of fuel fired = N21+N22 kg/kg

= ( 0.0094+2.893) kg/kg = 2.9024 kg/kg of fuel

Qfgw, Total wet flue gas produced per kg of fuel fired = 0.929+0.371+0.008+0.144+2.9024 = 4.3544 kg/kg

Wet flue gas produced, kg /kg of fuel fired = 4.354 kg/kg Qfgd, Total dry flue gas produced per kg of fuel fired = 0.929+0.008+0.144+2.9024

= 3.983 kg/kg Dry flue gas produced, kg /kg of fuel fired = 3.983 kg/kg

wet gas kg / kg of

fuel

Mol. weight

CO2 0.929 44.04H2O 0.371 18.02SO2 0.008 64.06O2 0.144 32.00N2 2.9024 28.01

Total 4.3544 Total moles = 0.021+0.021+0.00012+0.005+0.104=0.15112

Mole.wt of flue gas = ((13.90x 44.01)+(13.90x 18.02)+(0.08x64.06)+(3.31x32)+(68.82x28.01)) / 100Mole.wt of flue gas = 29.01

100x0.929/4.3544=21.335 0.929/44.04 = 0.021 100x0.021/0.15112=13.90100x0.021/0.15112=13.90

Flue gas ( wet ) composition by % wt

Flue gas ( wet ) composition by % vol

No of moles / kg of fuel

Composition of Flue gas

100x0.371/4.3544=8.520100x0.008/4.3544=0.18372100x0.144/4.3544=3.307

0.371/18.02 = 0.021

100x2.9024/4.3544=66.654

100x0.00012/0.15112=0.08100x0.005/0.15112=3.31100x0.104/0.15112=68.82

0.008/64.06 = 0.00010.144/32 = 0.0052.9024/28.01 = 0.104

Results Summary

Dry air required, kg /kg of fuel fired = 3.757 kg/kg Wet air required, kg /kg of fuel fired = 3.863 kg/kg

Dry Flue gas produced, kg /kg of fuel fired = 3.983 kg/kg Flue gas produced, kg /kg of fuel fired = 4.354 kg/kg

Flue gas composition summaryWet by vol % Dry by vol%

Carbon di oxide = 13.90 % = 16.14 %Water vapour = 13.90 % = 0 %

Sulfur di oxide = 0.08 % = 0.09 %Oxygen = 3.31 % = 3.84 %

Nitrogen = 68.82 % = 79.93 %

COMBUSTION CALCULATIONS FOR FUEL PER KG BASIS Date & time: 2/1/14 5:39 PMPROJECT :

INPUTS FOR AIR & GAS CALCULATIONS Performance coal

Ta, Ambient temperature = 35 deg C P1, Relative humidity = 60 % Ma, Moisture in dry air = 0.02825 kg / kg

E, Excess air = 20 % Constituents of fuel ( % by weight )

C, Carbon = 26.67 % Carbon lost in ash = 1.169 %

carbon burnt = 25.501 % H, Hydrogen = 1.62 %

O, Oxygen = 8.7 % S, Sulphur = 0.38 %

N, Nitrogen = 0.94 % M, Moisture = 12 %

A, Ash = 49.7 %

Air requirement calculationsO2 reqd, kg/kg of Carbon in fuel = 2.644 kg/kg

O2 reqd, kg/kg of Hydrogen in fuel = 7.937 kg/kg O2 reqd, kg/kg of Sulphur in fuel = 0.998 kg/kg

Solid crbon unburnt from Efficiency calc, = 0.012 kg/kg O2 reqd, for the Carbon in fuel =( 0.2667-0.012)x2.644 /100) kg/kg

= 0.674 kg/kg O2 reqd, for the Hydrogen in fuel =( 7.937x1.62 /100) kg/kg

= 0.129 kg/kg O2 reqd, for the Sulphur in fuel =( 0.998x0.38 /100) kg/kg

= 0.004 kg/kg Stochiometric O2 reqd / kg of fuel = O2 reqd for C,H,S in fuel - O2 in fuel) kg/kgStochiometric O2 reqd / kg of fuel = ( 0.674+0.129+0.004) -(8.7 / 100) kg/kg

= 0.72 kg /kg of fuel Excess O2 required / kg of fuel = ( 0.72x / 100 ) kg /kg of fuel

= ( 0.72x 20 / 100 ) kg /kg of fuel = 0.144 kg/kg

Total O2 required / kg of fuel = ( 0.72+ 0.144) kg/kg = 0.864 kg/kg

Weight fraction of O2 in atmospheric air = 0.23 kg/kg Dry air required for Combustion, kg/kg of fuel =( 0.864/ 0.23) kg/kg

= 3.757 kg/kg Due to relative Humidity, wet air reqd, kg/kg of fuel =( 1 + 0.02825) x 3.757) kg/kg

Wet air required, kg /kg of fuel fired = 3.863 kg/kg Dry air required, kg /kg of fuel fired = 3.757 kg/kg

ITC tribeni performance coal

Gas weight constituents calculations

CO2 produced, kg/kg of Carbon in fuel = 3.644 kg/kg H2O produced, kg/kg of Hydrogen in fuel = 8.937 kg/kg

SO2 produced, kg/kg of Sulphur in fuel = 1.998 kg/kg

CO2 produced, for the Carbon in fuel =( 3.644x26.67 /100) kg/kg = 0.929 kg/kg

H2O produced, for the Hydrogen in fuel =( 8.937x1.62 /100) kg/kg = 0.145 kg/kg

H2O in combustion air = 0.02825x3.757 kg/kg = 0.106 kg/kg

H2O due to moisture in fuel = 12/100 kg/kg = 0.12 kg/kg

H2O due to air & H2 combustion& fuel moisture =( 0.106+0.145+0.12) kg/kg = 0.371 kg/kg

SO2 produced, for the Sulphur in fuel =( 1.998x0.38 /100) kg/kg = 0.008 kg/kg

O2 in flue gas ( Excess O2 added ) = 0.144 kg/kg

N21,Nitrogen due to fuel = N kg/kg = 0.0094 kg/kg

Weight fraction of Nitrogen in Dry Air = 0.77 kg/kg N22 due to Air, kg per kg of fuel = 0.77 x 3.757 kg/kg

= 2.893 kg/kg Total N2 in flue gas , kg/kg of fuel fired = N21+N22 kg/kg

= ( 0.0094+2.893) kg/kg = 2.9024 kg/kg of fuel

Qfgw, Total wet flue gas produced per kg of fuel fired = 0.929+0.371+0.008+0.144+2.9024 = 4.3544 kg/kg

Wet flue gas produced, kg /kg of fuel fired = 4.354 kg/kg Qfgd, Total dry flue gas produced per kg of fuel fired = 0.929+0.008+0.144+2.9024

= 3.983 kg/kg Dry flue gas produced, kg /kg of fuel fired = 3.983 kg/kg

wet gas kg / kg of

fuel

Mol. weight

CO2 0.929 44.04H2O 0.371 18.02SO2 0.008 64.06O2 0.144 32.00N2 2.9024 28.01

Total 4.3544 Total moles = 0.021+0.021+0.00012+0.005+0.104=0.15112

Mole.wt of flue gas = ((13.90x 44.01)+(13.90x 18.02)+(0.08x64.06)+(3.31x32)+(68.82x28.01)) / 100Mole.wt of flue gas = 29.01

100x0.929/4.3544=21.335 0.929/44.04 = 0.021 100x0.021/0.15112=13.90100x0.021/0.15112=13.90

Flue gas ( wet ) composition by % wt

Flue gas ( wet ) composition by % vol

No of moles / kg of fuel

Composition of Flue gas

100x0.371/4.3544=8.520100x0.008/4.3544=0.18372100x0.144/4.3544=3.307

0.371/18.02 = 0.021

100x2.9024/4.3544=66.654

100x0.00012/0.15112=0.08100x0.005/0.15112=3.31100x0.104/0.15112=68.82

0.008/64.06 = 0.00010.144/32 = 0.0052.9024/28.01 = 0.104

Results Summary

Dry air required, kg /kg of fuel fired = 3.757 kg/kg Wet air required, kg /kg of fuel fired = 3.863 kg/kg

Dry Flue gas produced, kg /kg of fuel fired = 3.983 kg/kg Flue gas produced, kg /kg of fuel fired = 4.354 kg/kg

Flue gas composition summaryWet by vol % Dry by vol%

Carbon di oxide = 13.90 % = 16.14 %Water vapour = 13.90 % = 0 %

Sulfur di oxide = 0.08 % = 0.09 %Oxygen = 3.31 % = 3.84 %

Nitrogen = 68.82 % = 79.93 %

DESIGN EFFICIENCY CALCULATIONS Date & time : 2/1/14 5:39 PMPROJECT :

INPUTS FOR EFFICIENCY CALCULATIONS HLS1, assumed unburnt carbon loss = 4 %

HLS6, Assumed radiation loss = 0.3 % HLS7, Manufacturer margin = 0 %

Ta, Ambient temperature = 35 deg C Rh, Relative humidity = 60 % Ma, Moisture in dry air = 0.02825 kg / kg

E, Excess air = 20 % Te, Boiler outlet gas temperature = 140 Deg C

A1, % Ash collection at location 1 = 15 % BedA2, % Ash collection at location 2 = 0 % BankA3, % Ash collection at location 3 = 5 % EconomiserA4, % Ash collection at location 4 = 5 % AirheaterA5, % Ash collection at location 5 = 0 % MDCA6, % Ash collection at location 6 = 75 % ESP

T1, Temperature of ash at location1 = 850 deg C T2, Temperature of ash at location2 = 300 deg C T3, Temperature of ash at location3 = 250 deg C T4, Temperature of ash at location4 = 150 deg C T5, Temperature of ash at location5 = 150 deg C T6, Temperature of ash at location6 = 150 deg C

Constituents of fuel H, Hydrgen = 1.62 % M, Moisture = 12 %

A, Ash = 49.7 % GCV, Gross calorific value of fuel = 2353 kcal /kg

DESIGN EFFICENCY CALCULATIONSAssumed heat loss through unburnt carbon in ash

HLS1, Unburnt carbon loss = 4 % Solid carbon loss = 4x2353 / 8050 %

= 1.17 % Calculations for Heat loss though ash

A, Ash content in fuel = 0.497 kg/kg C, Specific heat of ash = 0.22 kcal/kg Deg C

HLn, % Heat lost through ash at n'th location = A x (An /100 ) x C x (Tn-Ta) x 100 / GCV

HL1, % Heat lost through ash at a location 1 = 0.497x (15 / 100 ) x0.22x (850-35) x 100 / 2353 % HL1, % Heat lost through ash at a location 1 = 0.57 %

HL2, % Heat lost through ash at a location 2 = 0.497x (0 / 100 ) x0.22x (300-35) x 100 / 2353 % HL2, % Heat lost through ash at a location 2 = 0.00 %

ITC tribeni performance coal

HL3, % Heat lost through ash at a location 3 = 0.497x (5 / 100 ) x0.22x (250-35) x 100 / 2353 % HL3, % Heat lost through ash at a location 3 = 0.05 %

HL4, % Heat lost through ash at a location 4 = 0.497x (5 / 100 ) x0.22x (150-35) x 100 / 2353 % HL4, % Heat lost through ash at a location 4 = 0.03 %

HL5, % Heat lost through ash at a location 5 = 0.497x (0 / 100 ) x0.22x (150-35) x 100 / 2353 % HL5, % Heat lost through ash at a location 5 = 0.00 %

HL6, % Heat lost through ash at a location 6 = 0.497x (75 / 100 ) x0.22x (150-35) x 100 / 2353 % HL6, % Heat lost through ash at a location 6 = 0.40 %

HLS2, Total Heat loss through the ash = HL1+HL2+HL3+HL4+HL5+HL6= ( 0.57+0.00+0.05+ 0.03+0.00+0.40 )%

HLS2, Total Heat loss through the ash = 1.05 %

Calculations for Heat loss through moisture in air

Ww, weight of water in air = 0.02825 kg/kg Wd, Dry air required per kg of fuel = 3.757 kg/kg from combustion calc

Cp1, specific heat of water vapor at boiler exit temp = 0.4948 kcal/kg CCp2, specific heat of water vapor at ambient temp = 1 kcal/kg C

Ta, Ambient temperature = 35 deg C Te, Boiler exit temperature = 140 deg C

HLS3, % Heat lost through moisture in air = Ww x Wd x {(Cp1 x Te) -(Cp2 x Ta)}x 100 / GCV = 0.02825x3.757x[(0.4948x140)-(1x35]x100 /2353

HLS3, % Heat lost through moisture in air = 0.15 %

Calculations for Heat loss through moisture & hydrogen in fuel

H, hydrogen in fuel = 0.0162 kg/kg M, moisture in fuel = 0.12 kg/kg

Cp1, Specific heat of water vapor at boiler exit temp = 0.4948 kcal/kg L, latent heat of water = 595.4 kcal/kg

Ta, Ambient temperature = 35 deg C Te, Boiler exit temperature = 140 deg C

HLS4, % Heat lost through moisture & H2 in fuel ={M+(8.94 x H)} x [595.4+(Cp1 x Te) -Ta] x 100 / GCVHLS4, % Heat lost through moisture & H2 in fuel

HLS4, % Heat lost through moisture & H2 in fuel = 7.09 %

Calculations for Heat loss through dry flue gas

Qfgd, Dry flue gas produced per kg of fuel = 3.983 kg/kg

={ 0.12+ (8.94 x 0.0162)}x [ 595.4+(0.4948x 140) -35]x100/2353 %

Cp3, specfic heat of flue gas at boiler exit temp = 0.263 kcal/kg deg C

Cp4, specfic heat of flue gas at ambient temp = 0.259 kcal/kg deg C Ta, Ambient temperature = 35 deg C

Te, Boiler exit temperature = 140 deg C

HLS5, % Heat lost through dry flue gas =Qfgd x{ (Cp3 x Te) - (Cp4 x Ta)} x 100 / GCV

HLS5, % Heat lost through dry flue gas = 4.70 %

Assumed heat loss through radiationHLS6, Radiation loss = 0.3 %

Manufacturer marginHLS7, Manufacturer margin = 0 %

Total efficiency break upHLS1, Unburnt carbon loss = 4 %

HLS2, Total Heat loss through the ash = 1.05 % HLS3, Heat lost through moisture in air = 0.15 %

HLS4, Heat lost through moisture & H2 in fuel = 7.09 % HLS5, Heat lost through dry flue gas = 4.70 %

HLS6, Radiation loss = 0.3 % HLS7, Manufacturer margin = 0 %

Total losses = 4+1.05+0.15+7.09+4.70+0.3+0 = 17.29 %

Therefore, Boiler efficiency, = 100 - 17.29 % Boiler Efficiency = 82.71 %

=3.983x { ( 0.263 x 140) - (0.259x35)} x 100/2353 %

BOILER HEAT DUTY CALCULATIONS Date & time: 2/1/14 5:39 PMPROJECT : INPUTS FOR BOILER DUTY CALCULATIONS

Steam generation rate Nett = 72000 Kg/hMain steam pressure = 86 kg/cm2 g

Main steam temperature = 520 Deg CFeed water inlet temperature = 204.4 Deg C

Superheater Pressure drop = 5 kg/cm2 gSaturated steam flow from drum = 0 kg/h

Selected boiler efficiency = 82 %

BOILER HEAT DUTY CALCULATIONSMsup, Steam generation rate = 72000 kg / h

P1, Main steam pressure = 86 kg/cm2 g Ts, Main steam temperature = 520 deg C

Tw, Feed water inlet temperature = 204.4 deg C Hw, Feed water inlet enthalphy = 204.4 kcal / kg

Hs, Main steam enthalpy = 821.90 kcal / kg H, Heat added per kg of water = ( Hs - Hw )

= ( 821.90 - 204.4) kcal / kg H, Heat added per kg of water = 617.5 kcal / kg

Heat output of the boiler ( SH steam) = ( Msup x H) kcal / hr = ( 72000 x 617.5) kcal / hr

Qo Heat output of the boiler ( SH steam) = 44460000 kcal / h Msat Saturated steam flow from drum = 0 kg / h

Saturated steam enthalpy = 655.23 kcal/kg Heat output thorugh the sat. steam = 0x( 655.23-204.4) kcal/kg

Qs heat output of the boiler ( saturated stea = 0 kcal/hr Qt Total heat output of the boiler = Qo+Qs kcal/hr

= ( 44460000 + 0 )kcal/hr Qt Total heat output of the boiler = 44460000 kcal/hr

Calculated Boiler efficiency = 82.71 %Selected Boiler Efficiency = 82 %

Fuel GCV = 2353 kcal /kgFuel firing rate = Qt x 100 / ( Eff x GCV )

= 44460000 x 100 / ( 82 x 2353 ) % = 23,043 kg / hr

ResultsTotal heat output of the boiler = 44460000 kcal / hr

Calculated boiler efficiency = 82.71 %Selected boiler efficency = 82%

Fuel firing rate = 23,043 kg / hrSteam fuel ratio = 3.12 kg / kg

ITC tribeni performance coal

UNDER FED FLUIDISED BED SIZING Date & time : 2/1/14 5:39 PMPROJECT :

INPUTS FOR FLUIDISED BED SIZING Tb, Design bed temperature = 925 Deg C

Steam generated nett = 72000 kg/hMain steam temperature = 520 Deg C

Main steam pressure = 87 kg/cm2 aFuel burnt rate = 23,043 kg/h

Wet air required, kg /kg of fuel fired = 3.863 kg/kg Flue gas produced, kg /kg of fuel fired = 4.354 kg/kg

Flue gas molecular weight = 29.01Te, Boiler exit temperature = 140 Deg C

Tca, Combustion air temperature = 195 Deg C Ta, Ambient temperature = 35 Deg C

Assumed carbon loss = 4 % Ts, Saturation temperature = 305 deg C

Constituents of fuel H, Hydrgen = 1.62 % M, Moisture = 12 %

A, Ash = 49.7 % GCV, Gross calorific value of fuel = 2353 kcal /kg

UNDERBED FLUIDISED BED SIZINGCalculations for bed cross sectional area

Wet flue gas produced per kg of fuel = 4.354 kg/kgFuel burnt rate = 23,043 kg/h

% in bed combustion assumed = 100 %Fuel burnt in bed = 23043 kg/h

Wet flue gas flow rate from bed = 4.354 x 23043 kg/h = 100,329.22 kg/h

Molecular wt of flue gas = 29.01 from air & gas calcK, altitude correction factor = 0.997

Thro bed Flue Gas volume flow rate at 0 deg C = 100,329.22 x 22.4 / 29.01 x 0.997= 77,702.07 Nm3 /hr

Thro bed Flue Gas volume flow rate at 0 deg C = 21.58 Nm3 / secDesign bed temperature = 925 Deg C

Gas flow at bed temperature = ( 21.58x ( 273 + 925 ) / 273 )m3 /sec = 94.70 m3 /sec

Bed width = 3670 mmBed length = 9200 mm

Bed cross sectional area available = 33.764 m2 Vf, Fluidisation velocity = 94.70 / 33.764

= 2.8 m/s

ITC tribeni performance coal

Calculations for bed heat transfer area

Unburnt carbon lossHL1, % Unburnt carbon loss = 4 %

Calculations for Heat loss though ash A, Ash content in fuel = 0.497 kg/kg

C, Specific heat of ash = 0.22 kcal/kg Deg C Ta, Ambient temperature = 35 deg C

Tb, Design bed temperature = 925 deg C HL2, % Heat lost through ash = A x C x (Tb-Ta) x 100 / GCV

= 0.497x 0.22x (925-35) x 100 / 2353 % HL2, % Heat lost through ash = 4.14 %

Calculations for Heat loss through moisture in airWw, weight of water in air = 0.02825 kg/kg

Wd, Dry air required per kg of fuel = 3.757 kg/kg from combustion calcCp1, specific heat of water vapor at bed temp = 0.581 kcal/kg C

Cp2, specific heat of water vapor at ambient temp = 0.51 kcal/kg C Tca, Combustion air temperature = 195 deg C

Tb, Design bed temperature = 925 deg C

HL3, % Heat lost through moisture in air = Ww x Wd x {(Cp1 x Tb) -(Cp2 x Tca)}x 100 / GCV = 0.02825x3.757x[(0.581x925)-(0.51x195]x100 /2353

HL3, % Heat lost through moisture in air = 1.98 %

Calculations for Heat loss through moisture & hydrogen in fuelH, hydrogen in fuel = 0.0162 kg/kg M, moisture in fuel = 0.12 kg/kg

Cpb, Specific heat of water vapor at bed temp = 0.581 kcal/kg L, latent heat of water = 595.4 kcal/kg

Ta, Ambient temperature = 35 deg C Tb, Design bed temperature = 925 deg C

HL4, % Heat lost through moisture & H2 in fuel ={M+(8.94 x H)} x [595.4+(Cpb x Tb) -Ta] x 100 / GCVHL4, % Heat lost through moisture & H2 in fuel

HL4, % Heat lost through moisture & H2 in fuel = 12.36 %

Calculations for Heat loss through dry flue gasQfgd, Dry flue gas produced per kg of fuel = 3.983 kg/kg

Cpb, specific heat of flue gas at bed temp = 0.3137 kcal/kg deg C Cpa, specific heat of flue gas at Tca = 0.2647 kcal/kg deg C

Tb, Design bed temperature = 925 deg C Tca, Combustion air temperature = 195 deg C

HL5, % Heat lost through dry flue gas =Qfgd x{ (Cp1 x Tb) - (Cp2 x Tca)} x 100 / GCV

HL5, % Heat lost through dry flue gas = 40.38 %

={ 0.12+ (8.94 x 0.0162)}x [ 595.4+(0.581x 925) -35]x100/2353 %

=3.983x { ( 0.3137 x 925) - (0.2647x195)} x

Calculation for Heat loss through radiation to SSHAb, Bed cross sectional area = 17.249 m2

e, Emissivity of waterwall surface = 0.9S, Steafan boltzmann constant = 4.9 x 10 ^ -8

Tb, bed temperature = 925 Deg CTsh, superheater steam temperature = 480 Deg C

Radiation heat loss to superheater =Ab x e x S x {( Tb + 273 )^4 - ( Ts + 273 )^4}= 17.249x0.9x4.9 x 10^-8x{( 925+273)^4-(480+273)^4 = 1,322,300 kcal/h

Fuel heat input in the bed = 23,043x 2353= 54220179 kcal/hHL6, % Radiation loss to SH = 100x 1,322,300/ 54220179HL6, % Radiation loss to SH = 2.44 %

Calculation for Heat loss through radiation to WWAb, Bed cross sectional area = 16.515 m2

e, Emissivity of waterwall surface = 0.9S, Steafan boltzmann constant = 4.9 x 10 ^ -8

Tb, bed temperature = 925 Deg CTs, saturation steam temperature = 305 Deg C

Radiation heat loss to superheater =Ab x e x S x {( Tb + 273 )^4 - ( Ts + 273 )^4}= 16.515x0.9x4.9 x 10^-8x{( 925+273)^4-(305+273)^4 = 1,418,895 kcal/h

Fuel heat input in the bed = 49.7x 29.01= 54220179 kcal/hHL7, % Radiation loss to WW = 100x 1,418,895/ 54220179HL7, % Radiation loss to WW = 2.62 %

Bed heat balance & HTA requiredHL1, Unburnt carbon loss = 4 %

HL2, Total Heat loss through the ash = 4.14 % HL3, Heat lost through moisture in air = 1.98 %

HL4, Heat lost through moisture & H2 in fuel = 12.36 % HL5, Heat lost through dry flue gas = 40.38 %

HL6, % Radiation loss to SH = 2.44 % HL7, % Radiation loss to WW = 2.62 %

Total losses = 4+4.14+1.98+12.36+40.38+2.44+2.62 = 67.92 %

Therefore, % heat to be transferred to Bed coil = 100 - 67.92 % % Heat transferred to Bed coil = 32.08 %

Fuel heat input in the bed = 54220179 kcal/hActual heat to be transferred to Bed coil = 32.08 x 54220179/ 100

= 17,393,833 kcal/hTb, bed temperature = 925 Deg C

Ts, Saturation temperature = 305 Deg CTemperature difference = (925 - 305)= 620 deg C

Heat transfer coeff = 220 kcal / kg m2 Deg C

Bed coil area required = 17,393,833/ ( 220 x 620)

Bed Coil HT area required, if plain = 127.52 m2Area reqd after reduction for above bed heat release = 1 x 127.52 = 127.52 m2

Area reqd after reduction for studs = 127.52 / 1.35 = 94.5 m2Length of bed coil reqd = 94.5 / 3.142 x0.051 m

= 589.8 mChecking possible bed area from Layout, for 900 mm ht'

Availble length of bed coil = 766.05 mBed Coil HTA Available, if plain = 3.14 x 50.8 /1000 x 766.05

= 122.26 m2Checking possible bed area from Layout, for 800 mm ht'

Availble length of bed coil = 665.55 mBed Coil HTA Available, if plain = 3.14 x 50.8 /1000 x 665.55

= 106.22 m2

Deciding the furnace volumeTotal Flue Gas volume flow rate at 0 deg C = 100,329.22 x 22.4 / 29.01 x 0.997

= 77,702.07 Nm3 /hrTotal Flue Gas volume flow rate at 0 deg C = 21.58 Nm3 / sec

Furnace avg gas temperature = 912 Deg CGas flow at furnace temperature = ( 21.58x ( 273 + 912 ) / 273 )m3 /sec

= 93.67 m3 /secTotal volume = 269.5 m3

Therefore, furnace residence time = 269.5 / 93.67 = 2.88 sec

Summary of results% above bed combustion = 0 %

Bed temperature = 925 Deg CFluidisation velocity = 2.8 m/sGas residence time = 2.88 sec

Bed oil length required = 589.8 mBed coil length available with 900 mm bed ht = 766.05 m

Bed oil length to be covered = 1.18 m ( in outer coil)

PROJECT :

INPUTS FOR DP NOZZLE SIZING CALCULATIONSAir temp at Airheater air inlet = 35 deg C

Airheater air outlet = 195 deg CNo off compartments = 6

No of PA lines per compartment = 25Volumetric air flow rate = 19.59 Nm3/s

Fuel transport air flow = 4.646 m3/s

Air nozzle hole size 3.26 mm 3.26No of hole per nozzle 16 8

No of air nozzles provided 3058 120fuel Line size 125 nb

Equiv no of nozzles per fuel feed point 0

Availble distributor plate length 3670 mmAvailable distributor plate width 9200 mm

Calculations of volumetric Air flow rate and air densitiesTotal airflow at 0 deg C = 19.59 Nm3 / s

Ta, ambient temperature = 35 deg CV 35, Total airflow at ambient temperature = 19.59x ( 273 +35 ) / 273 V 35, Total airflow at ambient temperature = 22.102 m3/s

Air temp at Airheater air outlet = 195 Deg C

V 195, Total airflow after airheating = 19.59x ( 273 +195 ) / 273 V 195, Total airflow at after airheating = 33.583 m3/s

Air flow % trhough bed 90Air flow through DP = 33.583 x 0.9 = 30.2247

Air nozzle hole diameter = 3.26No of holes per air nozzle = 16

Flow area per nozzle = 16 x 3.1416 x (3.26/ 2000 )^2 = 0.00013 m2

D0, Density of air at 0 deg C with elevation corr. = 1.268D1, Density of air at 35 deg C = 273 x 1.268/ (273 +35)

= 1.124 kg/m3 D2, Density of air at 195 deg C = 273 x 1.268/ (273 +195)

= 0.740 kg/m3Pressure drop in distributor plate during MCR flow condition

V 195, Total airflow at after airheating = 30.2247 m3/sMCR air flow through DP at hot condn = 30.2247 - 4.646

= 25.5787 m3/sCd, Coefficient of discharge = 0.7

= 3058

ITC tribeni performance coalDP NOZZLES NOW

Air nozzle flow area for type 1 & type 2 nozzles = 0.416410023543748Air velocity through a nozzle hole = 25.5787/ (0.41641)

= 61.43 m/sPressure drop at MCR condition = 0.740 x 61.43^2 / ( 2 x 9.81 x 0.7^ 2)Pressure drop at MCR condition = 290 mmwc

Pressure drop during MFC ( minimum fluidisation condition )

Selected distributor plate length = 3670Selected distributor plate width = 9200 mm

Actual Distributor plate area provided = 9200 x 3670/ 1000000 = 33.764 m2

Minimum fluidisation velocity at cold condition = 0.8 m/sMinimum fluidisation airflow = 0.8 x 33.764

= 27.0112 m3/sDensity of air at ambient condition = 1.124 kg/m3

Air nozzle flow area for type 1 & type 2 nozzles = 0.416410023543748Velocity through air nozzle hole = 27.0112 / 0.41641

= 65 m/sPressure drop at Min fluidisation condition = 1.124 x 65^2 / ( 2 x 9.81 x0.7^2)

= 494 mmwcResults summary

No off nozzles required = 4752No off nozzles provided = 3058

Selected distributor plate width = 3670 mmSelected distributor plate length = 9200 mmPressure drop at MCR condition = 290 mmwc

Pressure drop at Min fluidisation condition = 494 mmwc

ANNEXURE 2: DERATING OF THE BOILER CAPACITY

Photo 01: The stud to stud gap is more at the bends. Any pitch more than 20 mm is susceptible to erosion between the studs. It is advised to cover the bends with phoscast refractory. Incidentally this will help in reducing the bed coil area, which will help to derate the boiler steam generation.

Photo 02: The photo shows the covering of the bend in Thermax boilers to prevent the erosion of the bends.

Photo 03: The view of the bed coils with phoscast refractory.

Photo 04: The refractory lining can be seen above the coals nozzles. This will reduce the erosion rate. This will meet the requirement of derating the boiler capacity.

Photo 05: The refractory is to be applied to the tip of the studs only. Care should be taken in this application to avoid other complication.

Photo 06: The above photo shows the layout of the bed coil. With a 900 mm bed height, the entire bed coils are immersed in the bed. Instead of reducing the bed height, it is advised to go for partial refractory lining to retard the heat transfer. It is also possible to remove some of the inner bed coils and adjust the bed temperature for continuous operation of 50 TPH.

Photo 7: The above is a typical layout drawing showing the phoscast refractory applicable above the coal nozzle area. This helps to reduce the effectiveness of the bed coil and at the same time, protect the bed coil against localised erosion.

Photo 8: The above drawing shows the application detail for each bed coil depending on the location of the coal nozzle.

ANNEXURE 2.1: BED COIL HTA AND DP DROP AT 50 TPH LOAD

UNDER FED FLUIDISED BED SIZING Date & time : 2/1/14 5:51 PMPROJECT :

INPUTS FOR FLUIDISED BED SIZING Tb, Design bed temperature = 900 Deg C

Steam generated nett = 50000 kg/hMain steam temperature = 520 Deg C

Main steam pressure = 87 kg/cm2 aFuel burnt rate = 16,002 kg/h

Wet air required, kg /kg of fuel fired = 3.863 kg/kg Flue gas produced, kg /kg of fuel fired = 4.354 kg/kg

Flue gas molecular weight = 29.01Te, Boiler exit temperature = 140 Deg C

Tca, Combustion air temperature = 195 Deg C Ta, Ambient temperature = 35 Deg C

Assumed carbon loss = 4 % Ts, Saturation temperature = 305 deg C

Constituents of fuel H, Hydrgen = 1.62 % M, Moisture = 12 %

A, Ash = 49.7 % GCV, Gross calorific value of fuel = 2353 kcal /kg

UNDERBED FLUIDISED BED SIZINGCalculations for bed cross sectional area

Wet flue gas produced per kg of fuel = 4.354 kg/kgFuel burnt rate = 16,002 kg/h

% in bed combustion assumed = 100 %Fuel burnt in bed = 16002 kg/h

Wet flue gas flow rate from bed = 4.354 x 16002 kg/h = 69,672.71 kg/h

Molecular wt of flue gas = 29.01 from air & gas calcK, altitude correction factor = 0.997

Thro bed Flue Gas volume flow rate at 0 deg C = 69,672.71 x 22.4 / 29.01 x 0.997= 53,959.49 Nm3 /hr

Thro bed Flue Gas volume flow rate at 0 deg C = 14.99 Nm3 / secDesign bed temperature = 900 Deg C

Gas flow at bed temperature = ( 14.99x ( 273 + 900 ) / 273 )m3 /sec = 64.41 m3 /sec

Bed width = 3670 mmBed length = 9200 mm

Bed cross sectional area available = 33.764 m2 Vf, Fluidisation velocity = 64.41 / 33.764

= 1.91 m/s

ITC tribeni performance coal- 50 TPH load

Calculations for bed heat transfer area

Unburnt carbon lossHL1, % Unburnt carbon loss = 4 %

Calculations for Heat loss though ash A, Ash content in fuel = 0.497 kg/kg

C, Specific heat of ash = 0.22 kcal/kg Deg C Ta, Ambient temperature = 35 deg C

Tb, Design bed temperature = 900 deg C HL2, % Heat lost through ash = A x C x (Tb-Ta) x 100 / GCV

= 0.497x 0.22x (900-35) x 100 / 2353 % HL2, % Heat lost through ash = 4.02 %

Calculations for Heat loss through moisture in airWw, weight of water in air = 0.02825 kg/kg

Wd, Dry air required per kg of fuel = 3.757 kg/kg from combustion calcCp1, specific heat of water vapor at bed temp = 0.577 kcal/kg C

Cp2, specific heat of water vapor at ambient temp = 0.51 kcal/kg C Tca, Combustion air temperature = 195 deg C

Tb, Design bed temperature = 900 deg C

HL3, % Heat lost through moisture in air = Ww x Wd x {(Cp1 x Tb) -(Cp2 x Tca)}x 100 / GCV = 0.02825x3.757x[(0.577x900)-(0.51x195]x100 /2353

HL3, % Heat lost through moisture in air = 1.89 %

Calculations for Heat loss through moisture & hydrogen in fuelH, hydrogen in fuel = 0.0162 kg/kg M, moisture in fuel = 0.12 kg/kg

Cpb, Specific heat of water vapor at bed temp = 0.577 kcal/kg L, latent heat of water = 595.4 kcal/kg

Ta, Ambient temperature = 35 deg C Tb, Design bed temperature = 900 deg C

HL4, % Heat lost through moisture & H2 in fuel ={M+(8.94 x H)} x [595.4+(Cpb x Tb) -Ta] x 100 / GCVHL4, % Heat lost through moisture & H2 in fuel

HL4, % Heat lost through moisture & H2 in fuel = 12.15 %

Calculations for Heat loss through dry flue gasQfgd, Dry flue gas produced per kg of fuel = 3.983 kg/kg

Cpb, specific heat of flue gas at bed temp = 0.3126 kcal/kg deg C Cpa, specific heat of flue gas at Tca = 0.2647 kcal/kg deg C

Tb, Design bed temperature = 900 deg C Tca, Combustion air temperature = 195 deg C

HL5, % Heat lost through dry flue gas =Qfgd x{ (Cp1 x Tb) - (Cp2 x Tca)} x 100 / GCV

HL5, % Heat lost through dry flue gas = 38.89 %

={ 0.12+ (8.94 x 0.0162)}x [ 595.4+(0.577x 900) -35]x100/2353 %

=3.983x { ( 0.3126 x 900) - (0.2647x195)} x

Calculation for Heat loss through radiation to SSHAb, Bed cross sectional area = 17.249 m2

e, Emissivity of waterwall surface = 0.9S, Steafan boltzmann constant = 4.9 x 10 ^ -8

Tb, bed temperature = 900 Deg CTsh, superheater steam temperature = 480 Deg C

Radiation heat loss to superheater =Ab x e x S x {( Tb + 273 )^4 - ( Ts + 273 )^4}= 17.249x0.9x4.9 x 10^-8x{( 900+273)^4-(480+273)^4 = 1,195,548 kcal/h

Fuel heat input in the bed = 16,002x 2353= 37652706 kcal/hHL6, % Radiation loss to SH = 100x 1,195,548/ 37652706HL6, % Radiation loss to SH = 3.18 %

Calculation for Heat loss through radiation to WWAb, Bed cross sectional area = 16.515 m2

e, Emissivity of waterwall surface = 0.9S, Steafan boltzmann constant = 4.9 x 10 ^ -8

Tb, bed temperature = 900 Deg CTs, saturation steam temperature = 305 Deg C

Radiation heat loss to superheater =Ab x e x S x {( Tb + 273 )^4 - ( Ts + 273 )^4}= 16.515x0.9x4.9 x 10^-8x{( 900+273)^4-(305+273)^4 = 1,297,537 kcal/h

Fuel heat input in the bed = 49.7x 29.01= 37652706 kcal/hHL7, % Radiation loss to WW = 100x 1,297,537/ 37652706HL7, % Radiation loss to WW = 3.45 %

Bed heat balance & HTA requiredHL1, Unburnt carbon loss = 4 %

HL2, Total Heat loss through the ash = 4.02 % HL3, Heat lost through moisture in air = 1.89 %

HL4, Heat lost through moisture & H2 in fuel = 12.15 % HL5, Heat lost through dry flue gas = 38.89 %

HL6, % Radiation loss to SH = 3.18 % HL7, % Radiation loss to WW = 3.45 %

Total losses = 4+4.02+1.89+12.15+38.89+3.18+3.45 = 67.58 %

Therefore, % heat to be transferred to Bed coil = 100 - 67.58 % % Heat transferred to Bed coil = 32.42 %

Fuel heat input in the bed = 37652706 kcal/hActual heat to be transferred to Bed coil = 32.42 x 37652706/ 100

= 12,207,007 kcal/hTb, bed temperature = 900 Deg C

Ts, Saturation temperature = 305 Deg CTemperature difference = (900 - 305)= 595 deg C

Heat transfer coeff = 220 kcal / kg m2 Deg C

Bed coil area required = 12,207,007/ ( 220 x 595)

Bed Coil HT area required, if plain = 93.25 m2Area reqd after reduction for above bed heat release = 1 x 93.25 = 93.25 m2

Area reqd after reduction for studs = 93.25 / 1.35 = 69.1 m2Length of bed coil reqd = 69.1 / 3.142 x0.051 m

= 431.3 mChecking possible bed area from Layout, for 900 mm ht'

Availble length of bed coil = 766.05 mBed Coil HTA Available, if plain = 3.14 x 50.8 /1000 x 766.05

= 122.26 m2Checking possible bed area from Layout, for 800 mm ht'

Availble length of bed coil = 665.55 mBed Coil HTA Available, if plain = 3.14 x 50.8 /1000 x 665.55

= 106.22 m2Checking possible bed area from Layout, for 700 mm ht'

Availble length of bed coil = 474.15 mBed Coil HTA Available, if plain = 3.14 x 50.8 /1000 x 474.15

= 75.67 m2Deciding the furnace volume

Total Flue Gas volume flow rate at 0 deg C = 69,672.71 x 22.4 / 29.01 x 0.997= 53,959.49 Nm3 /hr

Total Flue Gas volume flow rate at 0 deg C = 14.99 Nm3 / secFurnace avg gas temperature = 912 Deg C

Gas flow at furnace temperature = ( 14.99x ( 273 + 912 ) / 273 )m3 /sec = 65.07 m3 /sec

Total volume = 269.5 m3Therefore, furnace residence time = 269.5 / 65.07

= 4.14 sec Summary of results

% above bed combustion = 0 % Bed temperature = 900 Deg C

Fluidisation velocity = 1.91 m/sGas residence time = 4.14 sec

Bed oil length required = 431.3 mBed oil length available for 900 mm bed ht = 766.05 m

Bed oil length to be covered fo 900 mm bed height = 2.23 m ( in outer coil)Bed oil length available for 800 mm bed ht = 665.55 m

Bed oil length to be covered fo 800 mm bed height = 1.56 m ( in outer coil)Bed oil length available for 700 mm bed ht = 474.15 m

Bed oil length to be covered fo 700 mm bed height = 0.29 m ( in outer coil)

PROJECT :

INPUTS FOR DP NOZZLE SIZING CALCULATIONSAir temp at Airheater air inlet = 35 deg C

Airheater air outlet = 195 deg CNo off compartments = 6

No of PA lines per compartment = 25Volumetric air flow rate = 13.60 Nm3/s

Fuel transport air flow = 4.646 m3/s

Air nozzle hole size 3.26 mm 3.26No of hole per nozzle 16 8

No of air nozzles provided 3178 120fuel Line size 125 nb

Equiv no of nozzles per fuel feed point 0

Availble distributor plate length 3670 mmAvailable distributor plate width 9200 mm

Calculations of volumetric Air flow rate and air densitiesTotal airflow at 0 deg C = 13.60 Nm3 / s

Ta, ambient temperature = 35 deg CV 35, Total airflow at ambient temperature = 13.60x ( 273 +35 ) / 273 V 35, Total airflow at ambient temperature = 15.344 m3/s

Air temp at Airheater air outlet = 195 Deg C

V 195, Total airflow after airheating = 13.60x ( 273 +195 ) / 273 V 195, Total airflow at after airheating = 23.314 m3/s

Air flow % through bed 100Air flow through DP = 23.314 x 1 = 23.314

Air nozzle hole diameter = 3.26No of holes per air nozzle = 16

Flow area per nozzle = 16 x 3.1416 x (3.26/ 2000 )^2 = 0.00013 m2

D0, Density of air at 0 deg C with elevation corr. = 1.268D1, Density of air at 35 deg C = 273 x 1.268/ (273 +35)

= 1.124 kg/m3 D2, Density of air at 195 deg C = 273 x 1.268/ (273 +195)

= 0.740 kg/m3Pressure drop in distributor plate during MCR flow condition

V 195, Total airflow at after airheating = 23.314 m3/sMCR air flow through DP at hot condn = 23.314 - 4.646

= 18.668 m3/sCd, Coefficient of discharge = 0.7

= 3178

ITC tribeni performance coal- 50 TPH loadDP NOZZLES NOW

Air nozzle flow area for type 1 & type 2 nozzles = 0.416410023543748Air velocity through a nozzle hole = 18.668/ (0.41641)

= 44.83 m/sPressure drop at MCR condition = 0.740 x 44.83^2 / ( 2 x 9.81 x 0.7^ 2)Pressure drop at MCR condition = 155 mmwc

Pressure drop during MFC ( minimum fluidisation condition )

Selected distributor plate length = 3670Selected distributor plate width = 9200 mm

Actual Distributor plate area provided = 9200 x 3670/ 1000000 = 33.764 m2

Minimum fluidisation velocity at cold condition = 0.8 m/sMinimum fluidisation airflow = 0.8 x 33.764

= 27.0112 m3/sDensity of air at ambient condition = 1.124 kg/m3

Air nozzle flow area for type 1 & type 2 nozzles = 0.416410023543748Velocity through air nozzle hole = 27.0112 / 0.41641

= 65 m/sPressure drop at Min fluidisation condition = 1.124 x 65^2 / ( 2 x 9.81 x0.7^2)

= 494 mmwcResults summary

No off nozzles required = 3468No off nozzles provided = 3178

Selected distributor plate width = 3670 mmSelected distributor plate length = 9200 mmPressure drop at MCR condition = 155 mmwc

Pressure drop at Min fluidisation condition = 494 mmwc

ANNEXURE 3: PHOSCAST SPECIFICATION AND APPLICATION

CASTWEL INDUSTRIES C-18/6 M.I.D.C INDUSTRIAL AREA,

NAGPUR-440 028. Tel:07104-36566,35993.Fax:07104-37666

SPECIFICATION OF CHEMICALLY BONDED PLASTIC REFRACTORY

Description Phoscast-90XR Service Temp OC (Max) 1650Refractoriness OC (Min) 1785Bulk Density , g/cc (Min) Sample dried at 110 OC for 24 h

2.88

Cold Crushing Strength , kg/cm2 (Min) 110 OC / 24h 350 OC / 10 h 550 OC / 10 h 1300 OC / 5 h

650 650

675 875

Permanent Linear Change, % (Max) 110 OC / 24 h 1000 C / 5 h 1300 OC / 5 h

-0.10 -0.30

-0.60

Modulus of Rupture, kg/cm2 (Min) 110 OC / 24 h 350 OC / 10 h 550 OC / 10 h 1300 OC / 5 h

125 125 145

190 Chemical Analysis, % Al2O3 (Nominal) SiO2 (Max) Fe2O3 (Max) P2O5 (Nominal) CaO (Max) TiO2 (Max) Spalling cycle (at 1000C to water quenching)

92.0 4.0 0.30 4.00

0.30 0.90 + 25

Abrasion loss, cc (Max) (ASTM:C-704-93) Prefired At 110 0C / 24 h At 350 OC / 10 h At 550 C/ 10 h At 815C At 1300 OC / 5 h

5.0 4.5 4.0 4.0 3.5

Binder Requirement % 9.5 Thermal Conductivity at 1000oC (HFT)

Kcal/m/hr/C 2.0 2.2

Method of Application Ramming (Hand / Machine)

Note : The above specification pertains to supply of Phoscast-90XR chemically bonded ramming refractory for major lining in CFBC/AFBC boiler. It is recommended for critical areas such as burners, pneumatic spreaders, ash recycle pipes and the walls. Phoscast-90XR refractory can also be used with SS-fibre where ever required by ramming.

CASTWEL INDUSTRIES

APPLICATION AND CURING PROCEDURE FOR CHEMICALLY BONDED PHOSCAST RANGE PLASTIC REFRACTORIES Phoscast-90 XR- Developed to protect bed coil tubes from erosion. This is a two component system consisting powder + liquid binder to be mixed at site. Applied by hand ramming on the studs of bed coil tube by maintaining the thickness of lining approx. 20 mm. After sufficient air drying and slow heating upto 350C min. this refractory sets into a hard abrasion resistance mass thus preventing the tube from erosion. Also the product has got high spalling resistance and good thermal conductivity. MIXING : The Phoscast plastic refractories is supplied in two components system i.e. the dry powder mix and the liquid binder (phosphoric acid). The dry powder packing is of 50 kg each which is to be mixed with 9.5% by weight of liquid binder ( i.e. 4.75 Kg / 2850 ml ). Water percentage for Phoscast-90 XR is 3.5% ( 1750 ml approx.) by weight of dry powder. The dry powder of 50 kg is discharged into a plastic mixing container and first the liquid binder ( phosphoric acid) is gradually added into the dry mix while kneading is on, using acid proof rubber handgloves. Subsequently, after adding water, material must be mixed thoroughly again till homogenous plastic mass is obtained . Now the plastic mass is ready for application after about 10 to 12 minutes of mixing. The Phoscast plastic refractory mix can be applied over a period of 2 hrs. ( covered with plastic sheet or liner) after mixing, without any effect on properties. For testing make the ball of the material with palm, drop it from 6 to 7 feet on floor. If does not break (only flattens from the bottom) indicates that mix is OK. APPLICATION : Phoscast can be applied by ramming with wooden mallet having adequately large head (3 dia x 5 length x 10 long handle). The desired lining or repair thickness is built up in several courses while ramming the mass to uniform thickness. Phoscast refractory should never be troweled to obtain smooth surface and the surface should be finished by ramming only. Any excess mass is to be sliced off with trowel edge and then finished by ramming again. For bed coil tube application of AFBC boiler:- The material pasty mass should be finger pressed into the studs of the tube with maximum force. Finish should be given by pressing the hand palm against material applied, using surgical type thin rubber hand gloves.

CURING : Phoscast refractory hardens adequately after about 12-14 hrs in ambient and then progressively develops strength on heating at elevated temperatures. The following curing schedule is recommended for Phoscast plastic refractory : Air Drying minimum 24 hours. After this refractory layer should be dried by providing halogen lights/ blower heater. This will help to dry the surface area speedily Ambient to 200C @40C per hour : 4 to 5 hours. Hold at 200C : 6 hours. 200C to 400C @ 40C per hour : 5 hours. Hold at 400C or max. : 6 hours or maximum. Gradual Cooling ( ambient) to be done for next 6-8 hours. For drying the refractory, the approximate quantity of firewood required is around 20 MT, for smaller size boilers. The size of the firewood should be 3 to 4 dia and length approx. 4 feet. Drying and Heating is essential for Phoscast-90 XR refractory, as this is a heat setting refractory.

ANNEXURE 4: SNAPSHOTS OF BOILER OPERAION ON 24TH JAN & ON 2ND FEB

Photo 01: The above shows the performance of the boiler on 24th January 2014. It could be in the transient condition, but it showed the limitation of ID fan. The steam generation was 43 TPH. All the three beds were in operation. The O2 level was 10.4%. The steam temperature before DESH was 506 deg C, which had exceeded the temperature limit of 485 deg C. The bed temperatures were too low at 2nd and 3rd compartments. The ID inlet draft was -140 mmWC. The ID fan rpm was full open. The main steam temperature was at 539 deg C. The free board temperature was at 471 deg C. The windbox pr was at 583 mmWC and bed ht was at 380 mmWC.

Photo 02: The above shows the performance of the boiler on 2nd February 2014, after stabilising the 1st and 2nd compartments. The steam generation was 35.5 TPH. The O2 level was 7.22%. The steam temperature before DESH was 428 deg C, which is below the temperature limit of 485 deg C. The bed temperatures were quite stable and average is 870 deg C. The ID inlet draft was -56 mmWC. The ID fan rpm was 45%. The main steam temperature was at 505 deg C. The free board temperature was at 564 deg C. The windbox pr was at 505 mmWC and bed ht was at 338-356 mmWC. The PA header pressure was 985 mmWC. The 3rd compartment damper sealing was found to be good.

Photo 03: The above shows the performance of the boiler on 24th January 2014, with 2nd and 3rd compartments in operation. The steam generation was 40 TPH. The O2 level was 6.11%. The steam temperature before DESH was 445 deg C, which was below the temperature limit of 485 deg C. The bed temperature average is above 875 deg C. The ID inlet draft was -99 mmWC. The ID fan rpm was 65%. The main steam temperature was at 516 deg C. The free board temperature was at 727 deg C. The windbox pr was at 525 mmWC and bed ht was at 350 mmWC. The PA lines in the first compartment was kept open, anticipating additional load. As the TG exhaust temperature was going above 85 deg C, the generation was not raised further.

main report ITC tribeni.pdfAnnexure 1.1 review of log sheets.pdfAnnexure 1.2. photos.pdfAnnexure 1.3 fan sizing for 72 TP