successful commissioning of an AFBC boiler

3 February, 2014 REPORT ON TROUBLESHOOTING BOILER COMMISSIONING PROBLEM By Venus energy audit system The visit was madeto 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 35 deg C to DP DP drop for 494 MFC mmWC 100 deg C 408 mmWC 125 deg C 382 mmWC 150 deg C 359 mmWC 175 deg C 340 mmWC 195 deg C 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 Air flow, TPH 72 89 70 86.5 65 82.6 60 76.3 55 69.9 50 63.6 45 57.2 40 50.9 35 44.5 30 38.1 25 31.8 20 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. As such the draft at ESP outlet was less as compared to design head of 195 mmWC. However PA flow should be optimised for a minimum suction at mixing nozzle. Desuperheater sizing . When the feed water temperature is too low. The +ve pressure is seen in many RCC chimney. It is seen by calculations that the gas flow would be around 50 m3/s at ID inlet. ID fan sizing During the operation on 25th and 26th Jan 2014. The duct velocities are presented photo 5 in annexure 1. say 900 deg C. the bed evaporators have to do the job of sensible heat as well as latent heat. This is the draft generated at the ID fan suction with a discharge pressure of 26 mmWC. The draft at the base of the chimney will be 1. Excess to this will lead to high spillage to the next compartment.3. It is like the entire bed can be used for steam generation of 46 TPH. During 1st compartment / 2nd compartment operation. We can say per feeder around 3 TPH air should be OK. This will correspond to a DP drop of 127 mmWC and a fluidisation velocity of 1. will be 19. will be 14. the bed height has to be reduced and / or bed coil heating surface has to be reduced. There is no shortage of fan capacity. This is without considering the entry loss.Once the bed is at rated bed temperature. The fan sizing calculations were done and it was found that the fan sizing is OK. There is no under-sizing of the duct. Flue gas duct sizing between the APH and ESP The air and gas calculations were done for the design coal – 2353 kcal/kg GCV. Thus the steam generation rate at bed coil is less. Chimney sizing The gas velocity inside chimney at 20% EA for 2353 GCV coal with 82% efficiency and at 135 deg C. the DP drop should be 150 – 200 mmWC. But to achieve the 900 deg C. when the air temperature is 125 deg C.8 m/s. Later it was raised to 120 deg C. This will be known once all the compartments are to be put in to operation. Already 26 mmWC back pressure is considered in ID fan selection. The gas smell will be felt at the vent holes provided in RCC shell.2.8 mmWC. exit loss and transition losses at every transition inside the chimney. The Oxygen was reported to be 11. The PA flow (with a design velocity of 14 m/s). Localised turbulence persists at chimney base.5 TPH for all compartment operation.4 m/s. the ID fan draft had been maximum -150 mmWC. It is likely to be around 15 mmWC. The duct size of 1848 mm ID is quite suitable for the boiler. The heat duty of the boiler increases at lower feed water temperature. See calculation attached in annexure 1. 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. It is seen that the gas velocity at the APH outlet duct will be 12. then we can say the ID fan does not have capacity.2 m/s. In case there was a high draft loss anywhere in the flue gas circuit. The calculation sheet is attached in annexure 1. The SA needs to be closed for this condition so that all the air is admitted at air nozzles. The feedwater temperature was initially at room temperature.5 % at APH outlet. the generation is derated to 65% in a bed.4. Burner air flow should be reduced to a minimum. This is not advisable.46 m/s.4 x 4 mm. All the compartment dampers were checked. the refractory removal will not affect the steam temperature.48 TPH will be 2.  First cause is the operational procedures required for this boiler configuration. The refractory removal done in the waterwall after the SSH will lower the steam temperature at a load of 72 TPH. In the 3rd compartment. The spray water temperature is assumed to be 204 deg C by us. It is advised to operate the PA flow as optimum as possible. The line velocity at 4. The spray water line size is 33.48 TPH at 88% valve opening. 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 heat transfer areas of SSH. The wind box pressure data was not available for the 3rd compartment in 25th / 26th January logsheet. The control valve is sized for 4. PSH B and PSH A are found to be in order. See the calculation attached in annexure 1. It is seen that the PSH B outlet piping is selected to be P11 material. Conclusion The various reasons discussed above points out to two causes. The spray water flow required with 204 deg C water will be 2530 kg/h. If the coal was fed more the steam generation would have simply touched 72 TPH. This included improper stabilisation of 1st and 2nd compartment operation.5. the predicted performance of SH (for the design coal – 2353 kcal/kg) is given. The DP drop in the 1st and 2nd compartment had been as high as 300 mmWC. The PA flow in idle compartment can be substantial. It is seen the spray water temperature will be 140 deg C as per the scheme here. The coil and piping can withstand a service temperature of 485 deg C as per code formulae. manually the damper shall be closed by the screw wheel operating arrangement.6. It can be used only for full load operation. It is advised to keep it closed till the 3rd compartment is activated. In annexure 1. There is no under-sizing of the valve. It may be necessary to have air register pressure of say 25 mmWC only. Since the plant load is expected to be around 50 TPH. The DP values must be known to . The PSH B coil material is T11 material at the hot end. It is advisable to keep the PA header pressure as minimum as possible. The line velocity can be up to 3 m/s.The superheater surfacing is seen to be OK. Otherwise the construction of the damper is quite good and well thought of. there is a metal to metal contact instead of seal to metal contact. In a nonoperating compartment there can be leakages due to damper problem. SA is required based on CO and LOI levels only. Under low load operation. any air above the bed will reduce the DP pressure drop and may cause defluidization. This is just about the full load DP drop. Code has its safety margin. 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. in the upper left corner (as viewed from windbox side). The SA flow and spreader air flow should be in fully closed condition till the combustor operation is stabilised. As the coal grade is increased. the coils have to be covered up to 2. 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 fluidisation velocity will be 2. the operating bed height will increase as the heat taken out by the ash and moisture would come down. The combustion calculations are made for the performance coal and are presented in annexure 1. At 50 TPH load. The boiler should be started with fresh bed material or sieved bed material to size range of 0.98 m/s if the bed temperature can be maintained at 900 deg C. It will be necessary to cover nearly 1. The following are some of the points to be discussed with OEM in order to make the boiler suitable for the above requirements. In order to operate at rated bed height of 900 mm and at 925 deg C. This calls for certain changes in the combustor for smooth operation of the boiler. Similarly MFC DP drop should be known to them to enable proper mixing while starting a cold bed. See the photo 6 in annexure 1. the fluidisation velocity will be 1. The operational tips are covered in the discussions above. It is seen that the bed coil heat transfer area is on the higher side. limited spray in DESH and flexibility to handle sudden load changes. This carries a risk of ash accumulation when a compartment is slumped. It is possible to operate all the compartments with a height of 700 mm.6 m length of the outer bed coil in all 150 coils to have an operating bed height of 800 mm. For the present combustor cross section area. See layout in photo 6 of annexure 2. The present effective length of the outer bed coil is seen to be 3.7.8 m/s with the bed temperature of 920 deg C.2. Once the bed coil HTA is decided. Boiler configuration calls for additional care in operation. Each outer coil will have to be covered to length of 1.48 m and the length of the inner coil is 1. The studs provided at the bottom part of the bed coils work as anchors to support the refractory. The present load would be in the range of 36 TPH to 50 TPH only. the bed coil HTA plays a major role. The bed temperature can be improved if only parts of the bed coils are made ineffective. This is particularly related to clinker free operation. .   operators so that they operate based on allowable minimum and maximum DP drop for operation. 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.5 to 2 mm size shall be used. entire bed operation for 50 TPH would result in low bed temperature / low bed height.2 m. The fluidisation velocity also will come down. If we need to have a 900 mm operating height.18 m. part of the coils are to be covered with refractory so that the heat pick up by bed coil will be reduced.63 m. for 72 TPH. This is generally done by covering the longer bed coils with phoscast refractory (phosphate bonded high alumina castable). See work sheet attached in annexure 2. less loss on ignition in the ash. Combustor modification for 50 TPH – peak capacity In the combustor design. Nagpur. This cuts down the flexibility of load control. It is also possible to blank some of the coils at the header and adjust the heating surface as required. It will at least have 55 TPH peaking capacity. If load turn down is expected to be frequent. The phoscast is a product developed by Castwell industries. See a typical drawing made by us in photo 5 & 6 for another boiler. all the evaporative circuits come in to good circulation on the water side. peaking situations can be made. See photographs 1 to 3 in annexure 2. Further by operating at 950 deg C. there will be venting losses. 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. The application should be done by the supplier’s mason. There are equivalent products such ACC-plast and Tataplast. it is recommended to take up with OEM for details of refractory lining and the methodology of derating. The snapshots of DCS on 24th January and on 2nd February are enclosed in annexure 4. 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. See photo 4. It should be possible to achieve further turn down by slumping the first compartment. With excess air further small peaking capacity will increase. Since the boiler is under warranty period. The DP drop at 50 TPH steam generation is calculated to be 155 mmWC. The profile of phoscast is very important. Operating with 1 & 2 compartments and meeting the steam requirement would put the third compartment coils in caustic gouging regime. the number of compartments has to be made as five. By doing the above. That is a must for proper water chemistry. This is with SA ports closed. . Without which. the boiler can be derated to a peak capacity of 50 TPH. But phoscast is found to go well. Refractory on waterwall can be further adjusted to achieve less spray or zero spray at 36 TPH load. so that all the combustion air is given at the nozzles in the DP. The castable should not project out of the tips of studs. The main steam temperature profile will not be a problem. which will make the boiler inefficient. By the above modifications. The phoscast lining was done in OEM’s boiler in their installations at SPB and JSW. See drawing in photo 5 of annexure 2. This is quite good as compared to DP of 86 mmWC being operated in many Cethar boilers. Balance refractory cover can be preferably done above coal nozzle area so that erosion above bed coil can be kept under control.The refractory cover is any how required at the bed coil bends where the studs are pitched at 40 mm. 36 TPH steam generation should be possible after the above modification is done. The specification by the supplier is attached in annexure 3. Flexibility for load turndown The boiler is provided with one small compartment and two bigger compartments. After this the steam temperature before DESH came under control. The water chemistry needs to be taken care of. While draining the bed. The 3rd compartment mixing was found to occur only at 650 mmWC airbox pressure.K. 2nd compartment activation was done in our presence. The surge in steam temperature is due to activation of a large size compartment. the 1st compartment must be activated for creating circulation. After the design check it was understood that the bed cold fluidisation would be difficult. As the bed temperature showed rising trend. Hence the bed material was emptied completely as per our request. This resulted in low bed temperatures. There was an earth fault trip in the transformer. the gates were closed and the line dechoking was done. 8. DP drop would be 155 mmWC. 5. The mixing was done several times before coal feeding. The PO4 levels have to be in the range of 2-4 ppm. The DP drop should be 175 mmWC. The bypass of DESH spray had to be opened. In addition as requested bed material was poured along the borders to control the spillage during mixing of the bed. As the 3rd bed was catching up with coal feed. 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. As per instruction. This made few lines to get choked. On refractory lining of bed coils. it would be possible to keep all the beds in operation for a load of 50 TPH. The bed height was increased to 380 mm when the1st and 2nd compartments were in operation.1.   K. The steep temperature rise is due to large sized bed activation. The air box pressure and bed height difference was maintained in the range of 300 mmWC by OEM operators. 7. This had helped in maintaining the bed temperature as the coal was not spilling in to the working PA lines to the bed. 9. the steam temperatures started crossing 530 deg C.Parthiban . though OEM operators were interested in overbed. ID fan loading was normal. clinkers were found in the bed. The beds were revived with underbed feeding. The PA lines were being dechoked without closing the coal feed gates above. The TSP and DSP are to be mixed at 70:30 ratio and used for this pressure to avoid caustic gouging. once the LP extraction flow was increased. 3. 2. 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. The steam requirement did not go up further as there was an exhaust temperature issue in turbine. However. The bed height recommended was 300 mm above the air nozzle. The boiler had to be run on low bed height as predicted. 4. On request. 10. once in a hour or two. the 1st compartment was slumped. 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. the boiler steam pressure was lowered to 78 kg/cm2 before activating 3rd compartment. Only 2nd and 3rd compartments are to be operated. New material was added. 6. This proved better stability. Boiler was started on 1st Feb evening and 2nd compartment activation could be done only on 2nd morning. ANNEXURE 1.1 REVIEW OF LOG SHEETS .   Photo 1: The bed temperatures are seen to be erratic. the third compartment activation was not successful. With this condition. . Some of the bed temperatures are too low. Further it cools the bed. .Photo 2: The DP drop is as high as 300 mmWC. This high DP will throw the bed material to non operating compartment. 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 gas flow had been high as indicated by the oxygen level. . The ID fan is selected with 195 mmWC. 2.ANNEXURE 1.PHOTOGRAPHS . . Once all the compartments are put in to operation there is no problem.Photo 1: The photo above shows the boiler configuration at this plant. This boiler will have high PSH outlet temperature during start up than expected. The burner and start up compartments are located below the nose. Steam generation was increased by increasing the bed height in the start up compartment before attempting second compartment activation. When start up compartment is located below the nose panel. In this boiler the steam pressure was purposely brought down before activation of 2nd compartment. the cavity in front of SH is not used up in cooling the flue gas.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. . .92 m3/s with 12.Photo 03: The gas flow is estimated to be 51.7% O2 at boiler outlet. Photo 04: The fan performance curve says that the fan can handle 52 m3/s at 150 mm draft. This is the condition when the boiler was generating 45 TPH steam with a feed water temperature of 130 deg C. There are no bottle necks anywhere in the gas ducting.Photo 05: The gas velocity is seen to be OK at APH to ESP duct. . This is for the performance coal of 2353 Kcal/kg GCV. The front section of the screen is of 0.5 mm opening and the rear has to be of 2 mm. Photo 06: It is advised to procure a rotary screen as shown above for regular screening and reuse of bed ash as bed material. ANNEXURE 1.3: FAN SIZING FOR PERFORMANCE COAL AT 72 TPH STEAM GENERATION . 043 kg/h = 100329.22 x 22.4 / ( 29. deg C = 140 Deg C = 3.58 Nm3 / sec Boiler exit temperature.354 kg/kg Molecular wt of flue gas = 29.354 kg/kg Fuel burnt rate = 23.22 kg/h Molecular wt of flue gas = 29. altitude correction factor = 0.997 ) = 77.997 Flue Gas volume flow rate at 0 deg C = 100329.01 from air & gas calc K.01 Wet air required per kg of fuel Fuel Feed Rate Margin on FD fan flow Margin on PA fan flow Margin on ID fan flow FAN SIZING CALCULATIONS Calculations of volumetric gas flow rate Wet flue gas produced per kg of fuel = 4.07 Nm3 /hr Flue Gas volume flow rate at 0 deg C = 21.702.043 kg/h Wet flue gas flow rate = 4.01 x 0.863 kg/kg = 23.FAN SIZING CALCULATION PROJECT : ITC tribeni performance coal INPUTS FOR FAN SIZING CALCULATIONS Gas temp at Air temp at Date & time: 2/1/14 4:37 PM Site elevation Airheater outlet Airheater air inlet Airheater outlet = 27 metres = 140 deg C = 35 deg C = 195 deg C Design air velocity in fuel piping = 14 m/s Fan details No of PA lines per compartment FD fan capacity (% MCR ) FD fan efficiency ID fan capacity (% MCR) ID fan efficiency PA fan capacity (% MCR ) PA fan efficiency = 25 = 100 % = 85 % = 100 % = 75 % = 100 % = 75 % FD fan design head = 1205 mmwc PA fan design head = 676 mmwc ID fan design head = 221 mmwc Flue gas generated per kg of fuel = 4.354 x 23.043 kg/h = 20 % = 20 % = 20 % . 19 Nm3/s Total Fuel air flow rate = 3.646x 273 / ( 273 + 125 ) )m3 /sec = 3.043 / 125) = 184.863 kg/kg Fuel firing rate = 23.36 x 0.65 m3 /sec Calculations of volumetric Air flow rate Wet air required per kg of fuel = 3.043 / 25) = 922 = ( 23. Volumetric Air flow rate = ( 21. 100 / 125 / 150 Design air velocity in fuel piping Total Fuel air flow rate Total Fuel air flow rate Air outlet Temperature Total Fuel air Volume flow rate = 25 = ( 23.1 x ( 100 +20 ) / 100 m3/s = 26.043 kg/h Wet air flow rate = 3.1 m3/s = 20 % = 22.4 / ( 28.Gas flow at boiler exit temperature = ( 21.36 x 0.19 x ( 28.4 = 14.69 Nm3 /hr Wet air volume flow rate at 0 deg C = 19.519.36 K. Altidue correction factor = 0.52 m3/s FD fan Design head = 1205 mmwc Assumed FD fan efficiency = 85 % FD fan operating power required = 100 x 26.58x ( 273 + 140 ) / 273 )m3 /sec = 32.10 m3 /sec Estimation of Fuel transport air flow Total no of Fuel lines Normal Fuel flow per line Fuel Flow w/o one Feeder Selected fuel line size.52 x 1205/ ( 101 x 85 ) kw .11 kg/h Molecular wt of wet air = 28.495.1416 x (130/2000)^2 x 14 m3/s = 4.10x 100 / 100 ) m3/s = 22.646 m3/s = 125 Deg C = ( 4.34 = 130 = 14 m/s = 25 x 3.997 Wet air volume flow rate at 0 deg C = 89015.997) x 3600 / 22.863 x 23.95 kg/h FAN SIZING CALCULATIONS FD fan sizing FD fan capacity (% MCR ) MCR airflow required for combustion MCR airflow of FD fan MCR airflow of FD fan Margin on FD fan flow Design Flow for FD fan = 100 % = 22.11 x 22.043 kg/h = 89015.58x ( 273 + 35 ) / 273 )m3 /sec Volumetric air flow rate = 22. mm Nb.997) = 70.59 Nm3 / sec Air temp at Airheater air inlet = 35 Deg C Hence.10 m3/s = ( 22. 8 54.1 x 49.52 1205 35 85 372.3 125.= 372.8 kw = 54.646 x ( 100 +20 ) / 100 m3/s = 5.3 kw = 125.58 x 676/ ( 101 x 75 ) kw = 49.8 kw Design flow Design head Design temperature Assumed effciency Operating power Min motor power Selected motor Kw m3/s mmwc Deg C % kw kw kw 400 90 132 .646 m3/s = ( 4.8 75 supply 5.18 x 221/ ( 101 x 75 ) kw = 114.2 kw Minimum motor power required for FD fan = 409.646 m3/s = 20 % = 4.4 400 supply 26.3 kw = 1.2 409.4 kw PA fan sizing PA fan capacity (% MCR ) MCR fuel transport airflow required MCR airflow of PA fan MCR airflow of PA fan Margin on PA fan flow Design Flow for PA fan PA fan Design head Assumed PA fan efficiency PA fan operating power required Minimum motor power required Minimum motor power required for PA fan ID fan sizing ID fan capacity (% MCR ) MCR gas flow produced MCR gas flow of ID fan MCR gas flow of ID fan Margin on ID fan flow Design Flow for ID fan ID fan Design head Assumed ID fan efficiency ID fan operating power required Minimum motor power required Minimum motor power required for ID fan Results summary FD fan reqd 26.2 kw Minimum motor power required = 1.65 m3/s = ( 32.1 x 114.1 x 372.65 x ( 100 +20 ) / 100 m3/s = 39.18 221 195 75 114.58 676 195 75 49.8 kw = 1.7 132 supply 42.65 m3/s = 20 % = 32.646x 100 / 100 ) m3/s = 4.13 1205 PA fan reqd 5.58 m3/s = 676 mmwc = 75 % = 100 x 5.65x 100 / 100 ) m3/s = 32.93 221 = 100 % = 32.53 676 195 ID fan reqd 39.7 kw = 100 % = 4.18 m3/s = 221 mmwc = 75 % = 100 x 39. ANNEXURE 1.4: DRAFT GENERATED AT CHIMNEY BASE ENWS-230-00 VENUS ENERGY AUDIT SYSTEM WO / Prop.Nr Client ITC TRIBENI DRAFT GENERATED AT CHIMNEY BASE Prepared By Approved By Name K.K.Parthiban Name Venus Energy Audit System Rev Nr. Revision Details INPUT: Total Height of the chimney , H Internal diameter of the chimney at top, D Density of air at atmospheric temperature , wa Gas density at mean temp, wg = = = = 67 1.45 1.0545 0.8555 9.81 m m Kg/m3 Kg/m3 m/s2 Sign Sign Rev by Document no xxx Date 31-Jan-14 Checked Date 219.81628 57.086645 0.06583033 0.05340715 ft inch lb/cft lb/cft Acceleration due to gravity , g = CALCULATION: Draft Generated at chimney base = = = (H x (wa-wg))*12/62.4 inWC 0.525 inWC 13.339 mmWC 13.339 103626 1.1689071 33.6 1.7 20.4 1.45 0.0783 2.175E-05 1162115 0.02 17.431724 16.730 16.730 mmWC kg/h m3/kg m3/s m2 m/s m kg/mh kg/ms 228455.952 lb/h Draft generated at the base of the chimney = W, gas fllow v, sp volume Q, gas flow Flow area V, velocity D, Stack dia µ, Viscosity of flue gas = = = = = = = = Reynolds number = f, friction factor = G, mass flux = Draft loss = = OUTPUT: Draft at Chimney base ( w/o considering entry & = exit loss & expn loss at each transition kg/m2s kg/m2 mmWC + 3.4 mmWC ( 9 transitions) Sheet 1 of 2 ENWS-230-00 Sheet 2 of 2 5: THERMAL PERFORMANCE OF THE SUPERHEATERS .ANNEXURE 1. FEGT is with the assumption that the bed temperature will be at 925 deg C. PSH B performance .SUPER HEATER PERFORMANCE CHECK SSH PERFORMANCE The gas flow is with 20% EA for the design coal. The superheater surfacing is adequate for 72 TPH steam generation. . There was no need for altering the refractory lining in the waterwall above SSH. The gas temperature at PSH B inlet is taken with a cavity drop of 20 deg C as the waterwall is refractory lined.The spray requirement will be only 2530 kg/h. PSH A performance The cavity temperature drop is taken as 10 deg C as the side waterwalls are exposed. 6: STRENGTH CALCULATIONS FOR PSH-B TUBE AND PSH B OUTLET PIPING .ANNEXURE 1. 5% minimum thickness of Pipe . Kg / cm Allowable Stress . 91 ) Where . ( nom.00 4.25 2 Working Pressure. t D thk 15.13 892.09 13.50 572.5 SA 213 T11 SA 213 T11 525 520 > 104 Kg / cm > 104 Kg / cm 2 2 IBR calculation for pipes Wp = 2 f E(T -C) D . 320) 2 minimum thickness of Tube . Thk .neg. Wp f t D P C Sr. tolerance = 12. less neg.5 % for BS 3059 PI (ERW Gr. No 1 = = = = = = Working pressure . Kg / cm 2 2 neg. Thk .20 Metal temp 500 485 104 Kg / cm 2 E = 1 for Seamless pipe Description Material SA 335 P11 SA 335 P11 Allowable Stress. Tol. Kg / cm 100.75 for pressure upto 70 kg/cm2 .5 44.00 Material Metal temp Allowable Stress.T + C Regulation : IBR 338 (a) Where . tolerance ). less neg. tolerance ).75 Pipe Size . Kg / cm 782.IBR calculation for tubes Wp = 2 f (T -C) D . tube Size .1 outlet to SSH inlet 219.47 2 Working Pressure.54 2 2 Link pipe between PSH 219. mm Design pressure = 0. Kg / cm 520.0 % for SA 213 T11.27 107. mm External diameter of tube . mm Sr. Kg / cm Allowable Stress .T + C Regulation : IBR 350 ( Eqn. Wp. f . mm External diameter of pipe .neg. Wp. T22 0 for pressure above 70 kg/cm2 0. f . ( nom. No Description D thk 4.1 > 104 Kg / cm > 104 Kg / cm2 .02 2 1 2 PSH 1B tubes PSH 1B tubes 44. Tol.5% for BS 3059 PII = 7. Wp f t D P C = = = = = = Working pressure .09 15.20 13. Kg / cm 94. mm Design pressure = 104 Kg / cm = 0. tolerance = 12. t 4. Kg / cm 2 2 neg.00 Thk. mm Thk.95 111.00 4. ANNEXURE 1.7: COMBUSTION CALCULATIONS FOR 72 TPH WITH PERFORMANCE COAL . 70 % by wt 100.62 % by wt 8.00 Kcal /kg INPUTS FOR EFFICIENCY CALCULATIONS LOI HLS1 unburnt Carbon in fly ash Carbon loss 2.70 % by wt 0.00 % by wt 49.01 2353.PROJECT : ITC tribeni performance coal INPUTS FOR COMBUSTION CALCULATIONS AIR & GAS CALCULATIONS Ta P1 Ma E Te El P Constituents of fuel C H O S N M A GCV Ambient temperature Relative humidity Moisture in dry air ( from tables) Excess air Boiler outlet gas temperature Site elevation Flue gas pressure FUEL Carbon Hydrogen Oxygen Sulphur Nitrogen Moisture Ash Gross GCV of fuel 35 60 0.94 % by wt 12.02825 20 140 27 5 Deg C % kg/kg % Deg C Metres mmwc assumed Performance coal 26.38 % by wt 0.36 4% 0.4 5 0 Kg/h kg/cm2 g Deg C Deg C kg/cm2 g kg/h .5 % =(LOI/(100-LOI)* Ash%*8050/GCV 4.3 % 0% Locations Bed Bank Economiser Airheater MDC ESP 850 300 250 150 150 150 Deg C Deg C Deg C Deg C Deg C Deg C HLS1 HLS6 HLS7 A1 A2 A3 A4 A5 A6 Carbon loss ( assumed ) Radiation loss ( assumed ) Manufacturer margin (assumed ) % Ash collection at location 1 % Ash collection at location 2 % Ash collection at location 3 % Ash collection at location 4 % Ash collection at location 5 % Ash collection at location 6 15 0 5 5 0 75 100 % % % % % % T1 Temperature of ash at location1 T2 Temperature of ash at location2 T3 Temperature of ash at location3 T4 Temperature of ash at location4 T5 Temperature of ash at location5 T6 Temperature of ash at location6 INPUTS FOR BOILER DUTY CALCULATIONS Steam generation rate Nett Main steam pressure Main steam temperature Feed water inlet temperature Superheater Pressure drop Saturated steam flow from drum 72000 86 520 204.67 % by wt 1. 71 82 % INPUTS FOR AIR.GAS DUCT.CHIMNEY SIZING CALCULATIONS Flue gas ducting SH outlet Economiser outlet Airheater outlet Air ducting Airheater outlet Design velocities Design velocity in gas duct Chimney design gas velocity Design velocity in air duct INPUTS FOR FAN SIZING CALCULATIONS Design air velocity in fuel piping No of PA lines Fan sizing FD fan capacity (% MCR ) FD fan efficency ID fan capacity (% MCR) ID fan efficency PA fan capacity (% MCR ) PA fan efficiency FD fan design head PA fan design head ID fan design head Margin on FD fan flow Margin on PA fan flow Margin on ID fan flow INPUTS FOR FLUIDISED BED SIZING CALCULATIONS Design bed temperature = 925 Deg C 14 m/s 25 100 85 100 75 100 75 % % % % % % Gas temp 500 270 140 Air temp 195 Deg C Deg C Deg C Deg C 16 m/s 15 m/s 10 m/s 1205 mmwc 676 mmwc 221 mmwc 20 % 20 % 20 % .Boiler efficiency Calculated Boiler efficiency selected 82. 013)*(11.3102 *S) / HHV } * 10^4 Kg air / GJ = {(1+0.94))/100 = 9.Nr Client Prepared By Name Sign Rev Revision Details Document no Dalmia cements Approved By Name Sign Rev by Checked Date WXXX-XX-DCS-XXX-XX GCV check for fuels from Ultimate analysis Date INPUTS Dry coal Carbon Hydrogen Sulphur Ash Oxygen Nitrogen HHV Dry HHV reported = = = = = = = = 26.00}*10^4 /100 Kg air / GJ = 336.67+ 34.2 For other fuels and coal.35 HHV.2 GCV verification by IGT formula .96*C + 144.00 2353 % by wt % by wt % by wt % by wt % by wt % by wt Kcal / kg Kcal / kg Therotical air required for fuels Table of air qty / fuel Oil fuels Coke oven gas Natural gas Anthracite Low vol bituminous Med vol bituminous US coals High vol bituminous sub bituminous Lignite Fluid Coke Delayed Softwood. MJ/kg = 34.013)*(11.5095*C + 34. Kcal/ kg = 2233.8.531 A .67 + 144.283* ( H2-O2/8)+ 4.353. N and S are weight fractions = ( 34. A . H.70 8.531* 49.38 49.70 / 8 ) + 9.094*C + 132.1.213 * ( 1.353.38) / 2.0745 .62 0.For Bituminous and anthracite coals only HHV.42* S where C. MJ/kg = 33.298* 1. Kcal/ kg = 2355.838 *0.70+ 0.70-11.8609 HHV.96 * 26. peat Wood hard wood Bagasse kg air / GJ Min 318 284 314 331 327 329 325 325 322 327 338 301 305 268 Max 327 301 318 348 333 335 333 327 325 338 349 312 314 301 GCV verification by Dulong formula .283*(1.67 1.38-1.986 ( O + N ) where C.62-8. O .38)/100 = 9.298* H + 6.5095*26.70 0. H.WO / Prop. If the air required does not match correct GCV Kg air / GJ = = { (1+0.3102 *0.70/8)+ 4.213 * (H2 .67+132.094* 26. theortical air shall be calculated and compared with the values in table 1.For subbituminous and lignite only HHV.11.42 * 0.62 .62+6.O2 / 8 ) + 9. O and S are weight fractions = (33.94 2.838 * S.986 ( 8. COMBUSTION CALCULATIONS FOR FUEL PER KG BASIS PROJECT : ITC tribeni performance coal INPUTS FOR AIR & GAS CALCULATIONS Ta. Relative humidity Ma. for the Carbon in fuel O2 reqd.863 kg/kg = 3.38 /100) kg/kg = 0.62 /100) kg/kg = 0. kg/kg of Sulphur in fuel Solid crbon unburnt from Efficiency calc.144 kg/kg = ( 0. kg /kg of fuel fired Dry air required. kg/kg of fuel Due to relative Humidity. Sulphur N.998x0. Carbon Carbon lost in ash carbon burnt H.23) kg/kg = 3.937x1.7 % Total O2 required / kg of fuel Weight fraction of O2 in atmospheric air Dry air required for Combustion. Oxygen S.757 kg/kg .004 kg/kg = O2 reqd for C.S in fuel . O2 reqd.62 % = 8.23 kg/kg =( 0.O2 in fuel) kg/kg = ( 0.644 /100) kg/kg = 0.674+0. kg/kg of Carbon in fuel O2 reqd.144) kg/kg = 0.94 % = 12 % = 49.72x / 100 ) kg /kg of fuel = ( 0. kg /kg of fuel fired = 2.501 % = 1. for the Hydrogen in fuel O2 reqd. Hydrogen O. kg/kg of fuel Wet air required.72+ 0. Excess air Constituents of fuel ( % by weight ) C.757 kg/kg =( 1 + 0.757) kg/kg = 3. for the Sulphur in fuel Stochiometric O2 reqd / kg of fuel Stochiometric O2 reqd / kg of fuel Excess O2 required / kg of fuel Date & time: 2/1/14 5:39 PM Performance coal = 35 deg C = 60 % = 0. Ash Air requirement calculations O2 reqd. Ambient temperature P1.72 kg /kg of fuel = ( 0.012)x2.38 % = 0.998 kg/kg = 0.012 kg/kg =( 0.129 kg/kg =( 0.02825 kg / kg = 20 % = 26.004) -(8.864/ 0.7 / 100) kg/kg = 0.129+0.7 % = 0. Moisture A.2667-0.H. Moisture in dry air E.937 kg/kg = 0.169 % = 25.67 % = 1.864 kg/kg = 0.674 kg/kg =( 7.72x 20 / 100 ) kg /kg of fuel = 0. Nitrogen M.644 kg/kg = 7.02825) x 3. wet air reqd. kg/kg of Hydrogen in fuel O2 reqd. 18372 O2 0.0094 kg/kg Weight fraction of Nitrogen in Dry Air = 0.15112=68.106+0.wt of flue gas = ((13.12) kg/kg = 0.021+0.335 H2O 0.937x1.929/44.06 = 0.01 Flue gas ( wet ) composition by % vol 0.90x 44.82 Total moles = 0.Gas weight constituents calculations CO2 produced.021/0.02)+(0. kg/kg of Sulphur in fuel = 1.998x0.371+0.01 = 0.021 100x0.9024/28.144 100x0.644 kg/kg H2O produced. for the Sulphur in fuel =( 1.15112=3.008+0.520 SO2 0.02825x3.005/0.008/64.144 kg/kg N21.04 = 0.371/4.008+0.90x 18.005+0. kg/kg of fuel fired = N21+N22 kg/kg = ( 0.371 100x0. kg/kg of Carbon in fuel = 3. No of moles / kg of weight fuel 44.3544=21.77 x 3.145+0.9024 = 4.31x32)+(68.00012+0. for the Carbon in fuel =( 3.0001 100x0. Total dry flue gas produced per kg of fuel fired = 0.929+0.62 /100) kg/kg = 0.01)) / 100 Mole.3544=3.757 kg/kg = 0.00 28.Nitrogen due to fuel = N kg/kg = 0.3544=66.15112=0.82x28.104/0.02 = 0. kg/kg of Hydrogen in fuel = 8.08 0.3544=8. kg /kg of fuel fired = 4.144+2.144/32 = 0.9024 kg/kg of fuel Qfgw.31 2.008 kg/kg O2 in flue gas ( Excess O2 added ) = 0.144+2.654 Total 4.00012/0.9024 100x2.wt of flue gas = 29.104 100x0.15112 Mole.893 kg/kg Total N2 in flue gas .3544 kg/kg Wet flue gas produced.983 kg/kg Composition of Flue gas wet gas Flue gas ( wet ) kg / kg of composition by % wt fuel CO2 0.998 kg/kg CO2 produced.644x26.15112=13.021 100x0.929+0.77 kg/kg N22 due to Air.06 32.9024/4.008 100x0.371 kg/kg SO2 produced.937 kg/kg SO2 produced.38 /100) kg/kg = 0.929 100x0.893) kg/kg = 2.021+0. for the Hydrogen in fuel =( 8.983 kg/kg Dry flue gas produced.008/4. kg per kg of fuel = 0.12 kg/kg H2O due to air & H2 combustion& fuel moisture =( 0.106 kg/kg H2O due to moisture in fuel = 12/100 kg/kg = 0.021/0.0094+2.01)+(13.757 kg/kg = 2.15112=13.01 . kg /kg of fuel fired = 3.90 0.929 kg/kg H2O produced.08x64.06)+(3.005 100x0.02 64. Total wet flue gas produced per kg of fuel fired = 0.04 18.307 N2 2.929/4.3544=0.90 0.104=0.144/4.145 kg/kg H2O in combustion air = 0.9024 = 3.354 kg/kg Qfgd.67 /100) kg/kg = 0.3544 Mol.371/18. 90 % = 0. kg /kg of fuel fired Flue gas composition summary Carbon di oxide Water vapour Sulfur di oxide Oxygen Nitrogen Wet by vol % = 13.93 % = 3.31 % = 68.354 kg/kg kg/kg kg/kg kg/kg . kg /kg of fuel fired Dry Flue gas produced.90 % = 13.983 = 4.82 % Dry by vol% = 16.09 % = 3.84 % = 79.14 % =0% = 0.Results Summary Dry air required.08 % = 3. kg /kg of fuel fired Flue gas produced.757 = 3.863 = 3. kg /kg of fuel fired Wet air required. 129+0.674 kg/kg =( 7.674+0. Excess air Constituents of fuel ( % by weight ) C. Carbon Carbon lost in ash carbon burnt H. kg/kg of Hydrogen in fuel O2 reqd.998x0. Moisture in dry air E.94 % = 12 % = 49.863 kg/kg = 3. kg/kg of Carbon in fuel O2 reqd.644 /100) kg/kg = 0.144 kg/kg = ( 0.23 kg/kg =( 0.7 / 100) kg/kg = 0.COMBUSTION CALCULATIONS FOR FUEL PER KG BASIS PROJECT : ITC tribeni performance coal INPUTS FOR AIR & GAS CALCULATIONS Ta. for the Sulphur in fuel Stochiometric O2 reqd / kg of fuel Stochiometric O2 reqd / kg of fuel Excess O2 required / kg of fuel Date & time: 2/1/14 5:39 PM Performance coal = 35 deg C = 60 % = 0.2667-0.72 kg /kg of fuel = ( 0.864 kg/kg = 0. for the Hydrogen in fuel O2 reqd.169 % = 25. for the Carbon in fuel O2 reqd. kg/kg of Sulphur in fuel Solid crbon unburnt from Efficiency calc.937x1.02825) x 3.004) -(8.144) kg/kg = 0.S in fuel .67 % = 1.864/ 0. Hydrogen O. Ash Air requirement calculations O2 reqd.757 kg/kg .998 kg/kg = 0.23) kg/kg = 3.02825 kg / kg = 20 % = 26.H. kg/kg of fuel Due to relative Humidity.937 kg/kg = 0.012)x2.62 % = 8. Relative humidity Ma.62 /100) kg/kg = 0. kg /kg of fuel fired = 2. Nitrogen M.38 % = 0. Sulphur N.38 /100) kg/kg = 0. wet air reqd.72+ 0.757 kg/kg =( 1 + 0.757) kg/kg = 3.644 kg/kg = 7.004 kg/kg = O2 reqd for C.501 % = 1.012 kg/kg =( 0.72x 20 / 100 ) kg /kg of fuel = 0. Ambient temperature P1.O2 in fuel) kg/kg = ( 0. Moisture A.129 kg/kg =( 0.7 % Total O2 required / kg of fuel Weight fraction of O2 in atmospheric air Dry air required for Combustion.72x / 100 ) kg /kg of fuel = ( 0. Oxygen S.7 % = 0. kg /kg of fuel fired Dry air required. kg/kg of fuel Wet air required. O2 reqd. wt of flue gas = 29.12) kg/kg = 0.371/18.3544 Mol.00 28.757 kg/kg = 0.654 Total 4.15112=68.145 kg/kg H2O in combustion air = 0.144/32 = 0.12 kg/kg H2O due to air & H2 combustion& fuel moisture =( 0. Total dry flue gas produced per kg of fuel fired = 0.335 H2O 0.82 Total moles = 0.01)) / 100 Mole.021+0.08 0.15112=0.893) kg/kg = 2.01 .144 kg/kg N21. kg/kg of Hydrogen in fuel = 8.520 SO2 0.144 100x0.3544=0.90x 18.937x1.005+0.104=0.9024 = 4.06 32.008+0.371+0. for the Hydrogen in fuel =( 8.008+0.18372 O2 0.02 = 0.371 kg/kg SO2 produced. kg/kg of fuel fired = N21+N22 kg/kg = ( 0.929+0.67 /100) kg/kg = 0.15112 Mole.0001 100x0.01 Flue gas ( wet ) composition by % vol 0.90 0.9024 100x2.15112=3.021/0.06 = 0.983 kg/kg Dry flue gas produced. Total wet flue gas produced per kg of fuel fired = 0.Nitrogen due to fuel = N kg/kg = 0.021 100x0.021+0.00012+0.929+0.01)+(13.Gas weight constituents calculations CO2 produced.9024 = 3.644 kg/kg H2O produced.005/0.371/4.145+0.937 kg/kg SO2 produced. No of moles / kg of weight fuel 44.15112=13.3544=3.929 100x0.3544=66.04 18.021/0.644x26.62 /100) kg/kg = 0.08x64.929/4.00012/0.02 64. for the Carbon in fuel =( 3.9024/28.757 kg/kg = 2.02)+(0.90x 44.06)+(3.106+0.9024 kg/kg of fuel Qfgw.31 2.144+2.005 100x0.008/64.90 0.008 100x0.77 x 3.3544=21.929 kg/kg H2O produced. for the Sulphur in fuel =( 1.144+2.9024/4.354 kg/kg Qfgd. kg per kg of fuel = 0.01 = 0.008 kg/kg O2 in flue gas ( Excess O2 added ) = 0.04 = 0.371 100x0.3544 kg/kg Wet flue gas produced.998 kg/kg CO2 produced.wt of flue gas = ((13.929/44.106 kg/kg H2O due to moisture in fuel = 12/100 kg/kg = 0.008/4.144/4. kg /kg of fuel fired = 4.0094+2. kg /kg of fuel fired = 3.82x28.104/0. kg/kg of Carbon in fuel = 3.307 N2 2.893 kg/kg Total N2 in flue gas .0094 kg/kg Weight fraction of Nitrogen in Dry Air = 0.021 100x0.02825x3.15112=13.31x32)+(68.3544=8.998x0.77 kg/kg N22 due to Air.983 kg/kg Composition of Flue gas wet gas Flue gas ( wet ) kg / kg of composition by % wt fuel CO2 0.104 100x0.38 /100) kg/kg = 0. kg/kg of Sulphur in fuel = 1. 84 % = 79.90 % = 13. kg /kg of fuel fired Flue gas produced. kg /kg of fuel fired Flue gas composition summary Carbon di oxide Water vapour Sulfur di oxide Oxygen Nitrogen Wet by vol % = 13.863 = 3.09 % = 3.90 % = 0.354 kg/kg kg/kg kg/kg kg/kg .983 = 4.93 % = 3. kg /kg of fuel fired Wet air required.31 % = 68. kg /kg of fuel fired Dry Flue gas produced.08 % = 3.757 = 3.82 % Dry by vol% = 16.Results Summary Dry air required.14 % =0% = 0. Moisture A. % Heat lost through ash at a location 1 = 0. % Ash collection at location 2 A3. % Ash collection at location 5 A6.22x (850-35) x 100 / 2353 % HL1. Ash GCV. Assumed radiation loss HLS7.DESIGN EFFICIENCY CALCULATIONS PROJECT : ITC tribeni performance coal INPUTS FOR EFFICIENCY CALCULATIONS HLS1. Gross calorific value of fuel Date & time : 2/1/14 5:39 PM =4% = 0.00 % . Excess air Te. Ambient temperature Rh.62 % = 12 % = 49. % Heat lost through ash at a location 2 = 0. % Ash collection at location 4 A5. Temperature of ash at location5 T6.497x (0 / 100 ) x0.02825 kg / kg = 20 % = 140 Deg C = 15 % =0% =5% =5% =0% = 75 % Bed Bank Economiser Airheater MDC ESP = 850 deg C = 300 deg C = 250 deg C = 150 deg C = 150 deg C = 150 deg C = 1. % Heat lost through ash at a location 2 = 0. % Ash collection at location 3 A4.497x (15 / 100 ) x0.3 % =0 % = 35 deg C = 60 % = 0. % Heat lost through ash at a location 1 = 0. Temperature of ash at location1 T2. % Heat lost through ash at n'th location = A x (An /100 ) x C x (Tn-Ta) x 100 / GCV HL1. Boiler outlet gas temperature A1. Temperature of ash at location3 T4.17 % Calculations for Heat loss though ash A.497 kg/kg C. Temperature of ash at location4 T5. Relative humidity Ma. % Ash collection at location 6 T1. Unburnt carbon loss = 4 % Solid carbon loss = 4x2353 / 8050 % = 1. Ash content in fuel = 0. Hydrgen M.7 % = 2353 kcal /kg DESIGN EFFICENCY CALCULATIONS Assumed heat loss through unburnt carbon in ash HLS1. Manufacturer margin Ta.22x (300-35) x 100 / 2353 % HL2.57 % HL2. assumed unburnt carbon loss HLS6. Specific heat of ash = 0. Temperature of ash at location2 T3. Moisture in dry air E. % Ash collection at location 1 A2. Temperature of ash at location6 Constituents of fuel H.22 kcal/kg Deg C HLn. % Heat lost through moisture in air = 0.22x (150-35) x 100 / 2353 % HL4.40 % HLS2.497x (5 / 100 ) x0. Dry flue gas produced per kg of fuel = 3.HL3. Ambient temperature Te.4 kcal/kg = 35 deg C = 140 deg C HLS4.757 kg/kg from combustion calc = 0.497x (75 / 100 ) x0. % Heat lost through moisture & H2 in fuel ={ 0. % Heat lost through moisture & H2 in fuel ={M+(8. hydrogen in fuel M. weight of water in air Wd. % Heat lost through ash at a location 5 = 0. % Heat lost through ash at a location 3 = 0. latent heat of water Ta.03 % HL5. Boiler exit temperature = 0.4+(Cp1 x Te) -Ta] x 100 / GCV HLS4. % Heat lost through ash at a location 4 = 0.0162 kg/kg = 0.09 % Calculations for Heat loss through dry flue gas Qfgd.02825 kg/kg = 3.12+ (8.22x (150-35) x 100 / 2353 % HL6. Dry air required per kg of fuel Cp1.00+0.22x (250-35) x 100 / 2353 % HL3.4948x140)-(1x35]x100 /2353 HLS3.40 )% HLS2.4948x 140) 35]x100/2353 % HLS4.22x (150-35) x 100 / 2353 % HL5.4948 kcal/kg C = 1 kcal/kg C = 35 deg C = 140 deg C HLS3.94 x H)} x [595.00+0. % Heat lost through moisture & H2 in fuel = 7.94 x 0. % Heat lost through ash at a location 4 = 0.03+0. % Heat lost through ash at a location 5 = 0.4948 kcal/kg = 595.983 kg/kg . specific heat of water vapor at boiler exit temp Cp2.02825x3. % Heat lost through ash at a location 6 = 0.57+0. % Heat lost through ash at a location 6 = 0. Specific heat of water vapor at boiler exit temp L.0162)}x [ 595. Ambient temperature Te.00 % HL6.497x (5 / 100 ) x0. Boiler exit temperature = 0.05+ 0. % Heat lost through moisture in air = Ww x Wd x {(Cp1 x Te) -(Cp2 x Ta)}x 100 / GCV = 0. moisture in fuel Cp1.757x[(0.4+(0.15 % Calculations for Heat loss through moisture & hydrogen in fuel H.12 kg/kg = 0.05 % HL4.05 % Calculations for Heat loss through moisture in air Ww. % Heat lost through ash at a location 3 = 0. Total Heat loss through the ash = 1. specific heat of water vapor at ambient temp Ta.497x (0 / 100 ) x0. Total Heat loss through the ash = HL1+HL2+HL3+HL4+HL5+HL6 = ( 0. Heat lost through moisture & H2 in fuel HLS5.15+7.983x { ( 0. = 100 .(0. Manufacturer margin =4 % = 1.3+0 = 17.263 kcal/kg deg C = 0. Ambient temperature Te.259 kcal/kg deg C = 35 deg C = 140 deg C HLS5.05+0.263 x 140) . Heat lost through moisture in air HLS4.70+0. Boiler efficiency.3 % =0 % Total losses = 4+1. Boiler exit temperature = 0. Radiation loss HLS7. Manufacturer margin = 0 % Total efficiency break up HLS1.70 % Assumed heat loss through radiation HLS6.09+4.05 % = 0.09 % = 4.Cp3.259x35)} x 100/2353 % HLS5.15 % = 7. Total Heat loss through the ash HLS3. specfic heat of flue gas at ambient temp Ta. Unburnt carbon loss HLS2. % Heat lost through dry flue gas =Qfgd x{ (Cp3 x Te) . Radiation loss = 0.70 % = 0.(Cp4 x Ta)} x 100 / GCV =3. specfic heat of flue gas at boiler exit temp Cp4.17. % Heat lost through dry flue gas = 4.3 % Manufacturer margin HLS7.71 % .29 % Boiler Efficiency = 82. Heat lost through dry flue gas HLS6.29 % Therefore. 4) kcal / kg H.Hw ) = ( 821.5) kcal / hr Qo Msat Heat output of the boiler ( SH steam) Saturated steam flow from drum Saturated steam enthalpy Heat output thorugh the sat.90 .12 kg / kg kg/cm2 g Deg C Deg C kg/cm2 g kg/h % heat output of the boiler ( saturated stea = 0 kcal/hr .90 kcal / kg H.BOILER HEAT DUTY CALCULATIONS PROJECT : ITC tribeni performance coal INPUTS FOR BOILER DUTY CALCULATIONS Date & time: 2/1/14 5:39 PM Steam generation rate Nett = 72000 Kg/h Main steam pressure = 86 Main steam temperature = 520 Feed water inlet temperature = 204. Main steam enthalpy = 821. Heat added per kg of water = 617.043 kg / hr Steam fuel ratio = 3.23-204.4 deg C Hw. Main steam pressure = 86 kg/cm2 g Ts.204.4 Superheater Pressure drop = 5 Saturated steam flow from drum = 0 Selected boiler efficiency = 82 BOILER HEAT DUTY CALCULATIONS Msup.71 % Selected Boiler Efficiency = 82 % Fuel GCV = 2353 kcal /kg Fuel firing rate = Qt x 100 / ( Eff x GCV ) = 44460000 x 100 / ( 82 x 2353 ) % = 23.4) kcal/kg = Qo+Qs kcal/hr = ( 44460000 + 0 )kcal/hr = 44460000 kcal/hr Calculated Boiler efficiency = 82. Heat added per kg of water = ( Hs .71 % Selected boiler efficency = 82% Fuel firing rate = 23. Feed water inlet temperature = 204.23 kcal/kg = 0x( 655.5 kcal / kg Heat output of the boiler ( SH steam) = ( Msup x H) kcal / hr = ( 72000 x 617.4 kcal / kg Hs. steam Qs Qt Qt Total heat output of the boiler Total heat output of the boiler = 44460000 kcal / h = 0 kg / h = 655.043 kg / hr Results Total heat output of the boiler = 44460000 kcal / hr Calculated boiler efficiency = 82. Feed water inlet enthalphy = 204. Main steam temperature = 520 deg C Tw. Steam generation rate = 72000 kg / h P1. Fluidisation velocity = 4.62 % = 12 % = 49. Boiler exit temperature Tca. altitude correction factor Thro bed Flue Gas volume flow rate at 0 deg C Thro bed Flue Gas volume flow rate at 0 deg C Design bed temperature Gas flow at bed temperature Bed width Bed length Bed cross sectional area available Vf. kg /kg of fuel fired Flue gas produced.70 m3 /sec = 3670 mm = 9200 mm = 33.043 kg/h = 100 % = 23043 kg/h = 4.01 x 0.863 kg/kg = 4. Moisture A. Hydrgen M.4 / 29. Design bed temperature = 925 Deg C Steam generated nett Main steam temperature Main steam pressure Fuel burnt rate Wet air required. Saturation temperature Constituents of fuel H.UNDER FED FLUIDISED BED SIZING PROJECT : ITC tribeni performance coal Date & time : 2/1/14 5:39 PM INPUTS FOR FLUIDISED BED SIZING Tb.22 x 22. Ash GCV. Ambient temperature Assumed carbon loss Ts.01 = 140 Deg C = 195 Deg C = 35 Deg C =4% = 305 deg C .329.329.764 = 2.354 x 23043 kg/h = 100.70 / 33.7 % = 2353 kcal /kg = 72000 kg/h = 520 Deg C = 87 kg/cm2 a = 23.043 kg/h = 3.354 kg/kg = 23.702.07 Nm3 /hr = 21. kg /kg of fuel fired Flue gas molecular weight Te. Combustion air temperature Ta.997 = 77.764 m2 = 94.997 = 100.8 m/s = 1.354 kg/kg = 29.22 kg/h = 29.01 from air & gas calc = 0.58x ( 273 + 925 ) / 273 )m3 /sec = 94. Gross calorific value of fuel UNDERBED FLUIDISED BED SIZING Calculations for bed cross sectional area Wet flue gas produced per kg of fuel Fuel burnt rate % in bed combustion assumed Fuel burnt in bed Wet flue gas flow rate from bed Molecular wt of flue gas K.58 Nm3 / sec = 925 Deg C = ( 21. % Unburnt carbon loss = 4 % Calculations for Heat loss though ash A. % Heat lost through dry flue gas = 40. Combustion air temperature = 195 deg C HL5. latent heat of water = 595. Ambient temperature = 35 deg C Tb.3137 x 925) .22 kcal/kg Deg C = 35 deg C = 925 deg C = A x C x (Tb-Ta) x 100 / GCV = 0. Specific heat of water vapor at bed temp = 0.Calculations for bed heat transfer area Unburnt carbon loss HL1.2647 kcal/kg deg C Tb.(Cp2 x Tca)} x 100 / GCV =3.22x (925-35) x 100 / 2353 % HL2. Design bed temperature = 925 deg C HL3. moisture in fuel = 0. weight of water in air = 0. hydrogen in fuel = 0. % Heat lost through moisture in air = 1.0162)}x [ 595.2647x195)} x HL5. specific heat of water vapor at ambient temp = 0.12 kg/kg Cpb.983 kg/kg Cpb.94 x 0.02825x3.757x[(0.98 % Calculations for Heat loss through moisture & hydrogen in fuel H. Combustion air temperature = 195 deg C Tb. % Heat lost through dry flue gas =Qfgd x{ (Cp1 x Tb) .02825 kg/kg Wd.497x 0. Design bed temperature HL2.36 % Calculations for Heat loss through dry flue gas Qfgd.581 kcal/kg L.12+ (8. Dry flue gas produced per kg of fuel = 3.581x 925) 35]x100/2353 % HL4. specific heat of flue gas at bed temp = 0. % Heat lost through ash = 4. Ambient temperature Tb. % Heat lost through moisture & H2 in fuel = 12. Ash content in fuel C.4 kcal/kg Ta.94 x H)} x [595. % Heat lost through moisture in air = Ww x Wd x {(Cp1 x Tb) -(Cp2 x Tca)}x 100 / GCV = 0.581x925)-(0. specific heat of flue gas at Tca = 0.757 kg/kg from combustion calc Cp1. Specific heat of ash Ta.51 kcal/kg C Tca.3137 kcal/kg deg C Cpa.983x { ( 0.4+(0. % Heat lost through moisture & H2 in fuel ={M+(8.0162 kg/kg M. % Heat lost through ash = 0. Design bed temperature = 925 deg C HL4. % Heat lost through moisture & H2 in fuel ={ 0. Design bed temperature = 925 deg C Tca.581 kcal/kg C Cp2. specific heat of water vapor at bed temp = 0.(0.14 % Calculations for Heat loss through moisture in air Ww.51x195]x100 /2353 HL3.38 % .4+(Cpb x Tb) -Ta] x 100 / GCV HL4. Dry air required per kg of fuel = 3.497 kg/kg = 0. Bed cross sectional area = 16.08 % Fuel heat input in the bed = 54220179 kcal/h Actual heat to be transferred to Bed coil = 32. bed temperature = 925 Deg C Ts.44 % HL7.08 x 54220179/ 100 = 17. % Radiation loss to WW = 2.62 % Total losses = 4+4.9 x 10^-8x{( 925+273)^4-(305+273)^4 = 1.9x4. Emissivity of waterwall surface = 0.300 kcal/h Fuel heat input in the bed = 23.44+2.38 % HL6.98+12.305)= 620 deg C Heat transfer coeff = 220 kcal / kg m2 Deg C . Bed cross sectional area = 17. Heat lost through moisture in air = 1. % heat to be transferred to Bed coil = 100 . bed temperature = 925 Deg C Ts.44 % Calculation for Heat loss through radiation to WW Ab.9 S. saturation steam temperature = 305 Deg C Radiation heat loss to superheater =Ab x e x S x {( Tb + 273 )^4 .14+1. superheater steam temperature = 480 Deg C Radiation heat loss to superheater =Ab x e x S x {( Tb + 273 )^4 . % Radiation loss to SH = 2.9 x 10 ^ -8 Tb. bed temperature = 925 Deg C Tsh. % Radiation loss to WW = 2. % Radiation loss to SH = 100x 1.62 = 67.249x0.9x4.515x0.249 m2 e. Steafan boltzmann constant = 4.393.418.515 m2 e. Total Heat loss through the ash = 4. Steafan boltzmann constant = 4.043x 2353= 54220179 kcal/h HL6.322.7x 29.36 % HL5. Emissivity of waterwall surface = 0.9 S. Unburnt carbon loss = 4 % HL2. Heat lost through dry flue gas = 40.418.833 kcal/h Tb.98 % HL4.01= 54220179 kcal/h HL7.( Ts + 273 )^4} = 16. Saturation temperature = 305 Deg C Temperature difference = (925 .322. % Radiation loss to WW = 100x 1.67.Calculation for Heat loss through radiation to SSH Ab.62 % Bed heat balance & HTA required HL1.9 x 10^-8x{( 925+273)^4-(480+273)^4 = 1. Heat lost through moisture & H2 in fuel = 12.14 % HL3.36+40.895 kcal/h Fuel heat input in the bed = 49.92 % % Heat transferred to Bed coil = 32. % Radiation loss to SH = 2.( Ts + 273 )^4} = 17.895/ 54220179 HL7.38+2.92 % Therefore.9 x 10 ^ -8 Tb.300/ 54220179 HL6. 52 = 127.88 sec Summary of results % above bed combustion = 0 % Bed temperature Fluidisation velocity Gas residence time Bed oil length required Bed coil length available with 900 mm bed ht Bed oil length to be covered = 925 Deg C = 2. furnace residence time = 269.4 / 29.8 /1000 x 766. for 800 mm ht' Availble length of bed coil = 665.52 / 1. if plain Area reqd after reduction for above bed heat release Area reqd after reduction for studs Length of bed coil reqd = 17.5 m2 = 94.8 m/s = 2.997 = 77.67 m3 /sec Total volume = 269.26 m2 Checking possible bed area from Layout.8 /1000 x 665.142 x0.05 m Bed Coil HTA Available.22 m2 Deciding the furnace volume Total Flue Gas volume flow rate at 0 deg C = 100.5 m3 Therefore.702.051 m = 589.58 Nm3 / sec Furnace avg gas temperature = 912 Deg C Gas flow at furnace temperature = ( 21.Bed coil area required Bed Coil HT area required.35 = 94.58x ( 273 + 912 ) / 273 )m3 /sec = 93.8 m = 766.8 m Checking possible bed area from Layout.05 = 122.07 Nm3 /hr Total Flue Gas volume flow rate at 0 deg C = 21.52 m2 = 1 x 127.14 x 50.5 / 3.393.14 x 50.5 / 93.67 = 2.833/ ( 220 x 620) = 127.52 m2 = 127.55 m Bed Coil HTA Available.55 = 106. for 900 mm ht' Availble length of bed coil = 766.88 sec = 589.18 m ( in outer coil) .01 x 0.05 m = 1. if plain = 3.329.22 x 22. if plain = 3. 268/ (273 +195) = 0. Density of air at 195 deg C = 273 x 1. Coefficient of discharge = 0.PROJECT : ITC tribeni performance coal DP NOZZLES NOW INPUTS FOR DP NOZZLE SIZING CALCULATIONS Air temp at Airheater air inlet = 35 deg C Airheater air outlet = 195 deg C No off compartments = 6 No of PA lines per compartment = 25 Volumetric air flow rate = 19.26 mm 16 3058 125 nb 0 3670 mm 9200 mm 3.583 x 0. Total airflow at ambient temperature = 22.102 m3/s = 195 Deg C = 19. Total airflow after airheating V 195.2247 . ambient temperature = 35 deg C V 35.26 8 120 Calculations of volumetric Air flow rate and air densities Total airflow at 0 deg C = 19. Total airflow at after airheating = 30. Density of air at 35 deg C = 273 x 1.646 = 25.59 Nm3 / s Ta.268/ (273 +35) = 1. Total airflow at after airheating Air flow % trhough bed Air flow through DP Air nozzle hole diameter No of holes per air nozzle Flow area per nozzle .26 = 16 = 16 x 3.9 = 30.7 = 3058 Air temp at Airheater air outlet V 195.2247 m3/s MCR air flow through DP at hot condn = 30.59x ( 273 +35 ) / 273 V 35.124 kg/m3 D2.740 kg/m3 Pressure drop in distributor plate during MCR flow condition V 195.268 D1.26/ 2000 )^2 = 0.59x ( 273 +195 ) / 273 = 33.1416 x (3.4. = 1.2247 = 3.00013 m2 D0. Density of air at 0 deg C with elevation corr.646 m3/s Air nozzle hole size No of hole per nozzle No of air nozzles provided fuel Line size Equiv no of nozzles per fuel feed point Availble distributor plate length Available distributor plate width 3. Total airflow at ambient temperature = 19.59 Nm3/s Fuel transport air flow = 4.583 m3/s 90 = 33.5787 m3/s Cd. Air nozzle flow area for type 1 & type 2 nozzles = 0.8 x 33.764 m2 Minimum fluidisation velocity at cold condition = 0.0112 / 0.81 x 0.7^2) = 494 mmwc Results summary No off nozzles required = 4752 No off nozzles provided = 3058 Selected distributor plate width = 3670 mm Selected distributor plate length = 9200 mm Pressure drop at MCR condition = 290 mmwc Pressure drop at Min fluidisation condition = 494 mmwc .124 kg/m3 Air nozzle flow area for type 1 & type 2 nozzles = 0.764 = 27.8 m/s Minimum fluidisation airflow = 0.43^2 / ( 2 x 9.0112 m3/s Density of air at ambient condition = 1.81 x0.416410023543748 Air velocity through a nozzle hole = 25.124 x 65^2 / ( 2 x 9.5787/ (0.41641 = 65 m/s Pressure drop at Min fluidisation condition = 1.416410023543748 Velocity through air nozzle hole = 27.7^ 2) Pressure drop at MCR condition = 290 mmwc Pressure drop during MFC ( minimum fluidisation condition ) Selected distributor plate length = 3670 Selected distributor plate width = 9200 mm Actual Distributor plate area provided = 9200 x 3670/ 1000000 = 33.740 x 61.43 m/s Pressure drop at MCR condition = 0.41641) = 61. ANNEXURE 2: DERATING OF THE BOILER CAPACITY . Incidentally this will help in reducing the bed coil area. It is advised to cover the bends with phoscast refractory. 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. . Any pitch more than 20 mm is susceptible to erosion between the studs.Photo 01: The stud to stud gap is more at the bends. Photo 04: The refractory lining can be seen above the coals nozzles. This will reduce the erosion rate.Photo 03: The view of the bed coils with phoscast refractory. This will meet the requirement of derating the boiler capacity. . Photo 06: The above photo shows the layout of the bed coil. Instead of reducing the bed height.Photo 05: The refractory is to be applied to the tip of the studs only. With a 900 mm bed height. the entire bed coils are immersed in the bed. It is also possible to remove some of the inner bed coils and adjust the bed temperature for continuous operation of 50 TPH. Care should be taken in this application to avoid other complication. it is advised to go for partial refractory lining to retard the heat transfer. .   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. 1: BED COIL HTA AND DP DROP AT 50 TPH LOAD .ANNEXURE 2. 354 x 16002 kg/h = 69. Design bed temperature = 900 Deg C Steam generated nett Main steam temperature Main steam pressure Fuel burnt rate Wet air required.71 x 22.01 from air & gas calc = 0.4 / 29. Combustion air temperature Ta.01 x 0. Ambient temperature Assumed carbon loss Ts.863 kg/kg = 4.672. kg /kg of fuel fired Flue gas produced.002 kg/h = 3.997 = 69.71 kg/h = 29.672. Gross calorific value of fuel UNDERBED FLUIDISED BED SIZING Calculations for bed cross sectional area Wet flue gas produced per kg of fuel Fuel burnt rate % in bed combustion assumed Fuel burnt in bed Wet flue gas flow rate from bed Molecular wt of flue gas K. Fluidisation velocity = 4.7 % = 2353 kcal /kg = 50000 kg/h = 520 Deg C = 87 kg/cm2 a = 16.002 kg/h = 100 % = 16002 kg/h = 4.764 = 1.959. Moisture A. Hydrgen M.62 % = 12 % = 49. kg /kg of fuel fired Flue gas molecular weight Te.354 kg/kg = 29.99x ( 273 + 900 ) / 273 )m3 /sec = 64.UNDER FED FLUIDISED BED SIZING PROJECT : ITC tribeni performance coal.41 m3 /sec = 3670 mm = 9200 mm = 33.997 = 53.41 / 33. Ash GCV. Saturation temperature Constituents of fuel H.354 kg/kg = 16.99 Nm3 / sec = 900 Deg C = ( 14. Boiler exit temperature Tca.764 m2 = 64.01 = 140 Deg C = 195 Deg C = 35 Deg C =4% = 305 deg C . altitude correction factor Thro bed Flue Gas volume flow rate at 0 deg C Thro bed Flue Gas volume flow rate at 0 deg C Design bed temperature Gas flow at bed temperature Bed width Bed length Bed cross sectional area available Vf.91 m/s = 1.50 TPH load Date & time : 2/1/14 5:51 PM INPUTS FOR FLUIDISED BED SIZING Tb.49 Nm3 /hr = 14. weight of water in air = 0.497 kg/kg = 0.3126 kcal/kg deg C Cpa.4 kcal/kg Ta. % Unburnt carbon loss = 4 % Calculations for Heat loss though ash A.497x 0. % Heat lost through dry flue gas =Qfgd x{ (Cp1 x Tb) .2647x195)} x HL5. Design bed temperature = 900 deg C HL3.15 % Calculations for Heat loss through dry flue gas Qfgd.4+(Cpb x Tb) -Ta] x 100 / GCV HL4. Combustion air temperature = 195 deg C HL5.94 x H)} x [595. % Heat lost through moisture & H2 in fuel ={M+(8. Design bed temperature HL2.4+(0.22 kcal/kg Deg C = 35 deg C = 900 deg C = A x C x (Tb-Ta) x 100 / GCV = 0.02825 kg/kg Wd.22x (900-35) x 100 / 2353 % HL2.02 % Calculations for Heat loss through moisture in air Ww. % Heat lost through ash = 0.51 kcal/kg C Tca.51x195]x100 /2353 HL3.757x[(0. % Heat lost through moisture & H2 in fuel = 12. Specific heat of ash Ta.12 kg/kg Cpb. % Heat lost through ash = 4. % Heat lost through moisture in air = Ww x Wd x {(Cp1 x Tb) -(Cp2 x Tca)}x 100 / GCV = 0.0162 kg/kg M. moisture in fuel = 0. Ambient temperature = 35 deg C Tb.577x 900) 35]x100/2353 % HL4. % Heat lost through dry flue gas = 38.0162)}x [ 595. Design bed temperature = 900 deg C Tca. specific heat of water vapor at ambient temp = 0. Ash content in fuel C. latent heat of water = 595. specific heat of water vapor at bed temp = 0. Dry air required per kg of fuel = 3.577x900)-(0.577 kcal/kg L.757 kg/kg from combustion calc Cp1.94 x 0.89 % Calculations for Heat loss through moisture & hydrogen in fuel H.577 kcal/kg C Cp2.2647 kcal/kg deg C Tb.Calculations for bed heat transfer area Unburnt carbon loss HL1. specific heat of flue gas at Tca = 0. hydrogen in fuel = 0.89 % . Design bed temperature = 900 deg C HL4.983 kg/kg Cpb.12+ (8. % Heat lost through moisture in air = 1. specific heat of flue gas at bed temp = 0.02825x3.(Cp2 x Tca)} x 100 / GCV =3.983x { ( 0. Specific heat of water vapor at bed temp = 0. % Heat lost through moisture & H2 in fuel ={ 0.(0. Dry flue gas produced per kg of fuel = 3. Ambient temperature Tb. Combustion air temperature = 195 deg C Tb.3126 x 900) . bed temperature = 900 Deg C Ts. Total Heat loss through the ash = 4.02+1. % Radiation loss to WW = 100x 1.249 m2 e.537 kcal/h Fuel heat input in the bed = 49.195.Calculation for Heat loss through radiation to SSH Ab.297.297. % heat to be transferred to Bed coil = 100 . % Radiation loss to SH = 3. % Radiation loss to SH = 3. % Radiation loss to WW = 3.7x 29. Saturation temperature = 305 Deg C Temperature difference = (900 . saturation steam temperature = 305 Deg C Radiation heat loss to superheater =Ab x e x S x {( Tb + 273 )^4 .89+3.515x0.89+12. Steafan boltzmann constant = 4.9 S.58 % Therefore. Heat lost through moisture & H2 in fuel = 12.9x4.305)= 595 deg C Heat transfer coeff = 220 kcal / kg m2 Deg C . Bed cross sectional area = 16.18 % Calculation for Heat loss through radiation to WW Ab.9 x 10 ^ -8 Tb. Bed cross sectional area = 17.9 x 10 ^ -8 Tb.537/ 37652706 HL7.89 % HL6.58 % % Heat transferred to Bed coil = 32. bed temperature = 900 Deg C Tsh.9 S. Emissivity of waterwall surface = 0.( Ts + 273 )^4} = 17.45 % Bed heat balance & HTA required HL1.548 kcal/h Fuel heat input in the bed = 16.548/ 37652706 HL6.15+38.15 % HL5.195.207.249x0.89 % HL4.007 kcal/h Tb. Emissivity of waterwall surface = 0. Heat lost through dry flue gas = 38. % Radiation loss to WW = 3.42 % Fuel heat input in the bed = 37652706 kcal/h Actual heat to be transferred to Bed coil = 32.45 % Total losses = 4+4.18 % HL7.67.9 x 10^-8x{( 900+273)^4-(480+273)^4 = 1.( Ts + 273 )^4} = 16.9 x 10^-8x{( 900+273)^4-(305+273)^4 = 1.02 % HL3. superheater steam temperature = 480 Deg C Radiation heat loss to superheater =Ab x e x S x {( Tb + 273 )^4 .515 m2 e.18+3.01= 37652706 kcal/h HL7. Unburnt carbon loss = 4 % HL2. bed temperature = 900 Deg C Ts.9x4. % Radiation loss to SH = 100x 1. Heat lost through moisture in air = 1.45 = 67.002x 2353= 37652706 kcal/h HL6. Steafan boltzmann constant = 4.42 x 37652706/ 100 = 12. 35 = 69.15 m Bed Coil HTA Available.051 m = 431.14 x 50.22 m2 Checking possible bed area from Layout.25 / 1.05 m Bed Coil HTA Available.07 = 4.959.05 m = 2.67 m2 Deciding the furnace volume Total Flue Gas volume flow rate at 0 deg C = 69.15 = 75.55 m Bed Coil HTA Available.8 /1000 x 766.56 m = 474.71 x 22.3 m = 766.15 m = 0.29 m ( in outer coil) ( in outer coil) ( in outer coil) . for 800 mm ht' Availble length of bed coil = 665.1 m2 = 69.23 m = 665.99 Nm3 / sec Furnace avg gas temperature = 912 Deg C Gas flow at furnace temperature = ( 14.007/ ( 220 x 595) = 93.5 m3 Therefore.14 x 50.55 = 106.8 /1000 x 665. if plain Area reqd after reduction for above bed heat release Area reqd after reduction for studs Length of bed coil reqd = 12.14 sec Summary of results % above bed combustion = 0 % Bed temperature Fluidisation velocity Gas residence time Bed oil length required Bed oil length available for 900 mm bed ht Bed oil length to be covered fo 900 mm bed height Bed oil length available for 800 mm bed ht Bed oil length to be covered fo 800 mm bed height Bed oil length available for 700 mm bed ht Bed oil length to be covered fo 700 mm bed height = 900 Deg C = 1.91 m/s = 4.07 m3 /sec Total volume = 269.55 m = 1. furnace residence time = 269.14 x 50.25 = 93.49 Nm3 /hr Total Flue Gas volume flow rate at 0 deg C = 14.3 m Checking possible bed area from Layout.8 /1000 x 474. if plain = 3.5 / 65.99x ( 273 + 912 ) / 273 )m3 /sec = 65.01 x 0. for 900 mm ht' Availble length of bed coil = 766. if plain = 3.Bed coil area required Bed Coil HT area required.997 = 53.05 = 122. for 700 mm ht' Availble length of bed coil = 474.26 m2 Checking possible bed area from Layout.142 x0.25 m2 = 1 x 93.25 m2 = 93.1 / 3.4 / 29.14 sec = 431.672. if plain = 3.207. Total airflow at ambient temperature = 13. Density of air at 35 deg C = 273 x 1.314 m3/s MCR air flow through DP at hot condn = 23.740 kg/m3 Pressure drop in distributor plate during MCR flow condition V 195. Total airflow after airheating V 195.26/ 2000 )^2 = 0.4.00013 m2 D0.668 m3/s Cd. ambient temperature = 35 deg C V 35. Coefficient of discharge = 0.268/ (273 +35) = 1. Total airflow at after airheating Air flow % through bed Air flow through DP Air nozzle hole diameter No of holes per air nozzle Flow area per nozzle .60x ( 273 +35 ) / 273 V 35.314 = 3.60 Nm3/s Fuel transport air flow = 4.PROJECT : ITC tribeni performance coal.60x ( 273 +195 ) / 273 = 23. = 1.314 .26 mm 16 3178 125 nb 0 3670 mm 9200 mm 3.26 = 16 = 16 x 3.124 kg/m3 D2.60 Nm3 / s Ta. Density of air at 195 deg C = 273 x 1.646 m3/s Air nozzle hole size No of hole per nozzle No of air nozzles provided fuel Line size Equiv no of nozzles per fuel feed point Availble distributor plate length Available distributor plate width 3.7 = 3178 Air temp at Airheater air outlet V 195. Total airflow at after airheating = 23.268/ (273 +195) = 0.314 m3/s 100 = 23. Total airflow at ambient temperature = 15.314 x 1 = 23. Density of air at 0 deg C with elevation corr.26 8 120 Calculations of volumetric Air flow rate and air densities Total airflow at 0 deg C = 13.646 = 18.268 D1.50 TPH load DP NOZZLES NOW INPUTS FOR DP NOZZLE SIZING CALCULATIONS Air temp at Airheater air inlet = 35 deg C Airheater air outlet = 195 deg C No off compartments = 6 No of PA lines per compartment = 25 Volumetric air flow rate = 13.1416 x (3.344 m3/s = 195 Deg C = 13. 81 x 0.764 = 27.41641 = 65 m/s Pressure drop at Min fluidisation condition = 1.0112 / 0.8 m/s Minimum fluidisation airflow = 0.7^2) = 494 mmwc Results summary No off nozzles required = 3468 No off nozzles provided = 3178 Selected distributor plate width = 3670 mm Selected distributor plate length = 9200 mm Pressure drop at MCR condition = 155 mmwc Pressure drop at Min fluidisation condition = 494 mmwc .124 kg/m3 Air nozzle flow area for type 1 & type 2 nozzles = 0.416410023543748 Velocity through air nozzle hole = 27.416410023543748 Air velocity through a nozzle hole = 18.Air nozzle flow area for type 1 & type 2 nozzles = 0.81 x0.7^ 2) Pressure drop at MCR condition = 155 mmwc Pressure drop during MFC ( minimum fluidisation condition ) Selected distributor plate length = 3670 Selected distributor plate width = 9200 mm Actual Distributor plate area provided = 9200 x 3670/ 1000000 = 33.8 x 33.124 x 65^2 / ( 2 x 9.764 m2 Minimum fluidisation velocity at cold condition = 0.41641) = 44.83^2 / ( 2 x 9.740 x 44.83 m/s Pressure drop at MCR condition = 0.0112 m3/s Density of air at ambient condition = 1.668/ (0. ANNEXURE 3: PHOSCAST SPECIFICATION AND APPLICATION . 30 4. Tel:07104-36566. Al2O3 SiO2 Fe2O3 P2O5 CaO TiO2 (Min) 650 650 675 875 (Max) -0.90 + 25 Spalling cycle (at 1000°C to water quenching) .0 4. NAGPUR-440 028.I. g/cc Sample dried at 110 OC for 24 h O (Max) (Min) (Min) Phoscast-90XR 1650 1785 2.CASTWEL INDUSTRIES C-18/6 M.35993.00 0. kg/cm2 110 OC / 24h 350 OC / 10 h 550 OC / 10 h 1300 OC / 5 h Permanent Linear Change.C INDUSTRIAL AREA. kg/cm2 110 OC / 24 h 350 OC / 10 h 550 OC / 10 h 1300 OC / 5 h Chemical Analysis.30 -0. % 110 OC / 24 h 1000 °C / 5 h 1300 OC / 5 h Modulus of Rupture.D.10 -0.0 0.30 0.Fax:07104-37666 SPECIFICATION OF CHEMICALLY BONDED PLASTIC REFRACTORY Description Service Temp C Refractoriness OC Bulk Density .60 (Min) 125 125 145 190 % (Nominal) (Max) (Max) (Nominal) (Max) (Max) 92.88 Cold Crushing Strength . ash recycle pipes and the walls.0 – 2.2 Ramming (Hand / Machine) Note : The above specification pertains to supply of Phoscast-90XR chemically bonded ramming refractory for major lining in CFBC/AFBC boiler. Phoscast-90XR refractory can also be used with SS-fibre where ever required by ramming.5 2. .5 Binder Requirement % Thermal Conductivity at 1000 C (HFT) Kcal/m/hr/°C Method of Application o 9.Abrasion loss. cc (ASTM:C-704-93) Prefired At 110 0C / 24 h At 350 OC / 10 h At 550 °C/ 10 h At 815°C At 1300 OC / 5 h (Max) 5.0 4.0 3. It is recommended for critical areas such as burners.5 4. pneumatic spreaders.0 4. Applied by hand ramming on the studs of bed coil tube by maintaining the thickness of lining approx.e. Subsequently. This is a two component system consisting powder + liquid binder to be mixed at site. After sufficient air drying and slow heating upto 350°C min. Also the product has got high spalling resistance and good thermal conductivity.The material pasty mass should be finger pressed into the studs of the tube with maximum force. Water percentage for Phoscast-90 XR is 3. this refractory sets into a hard abrasion resistance mass thus preventing the tube from erosion. . APPLICATION : Phoscast can be applied by ramming with wooden mallet having adequately large head (3” dia x 5” length x 10” long handle).Developed to protect bed coil tubes from erosion.CASTWEL INDUSTRIES APPLICATION AND CURING PROCEDURE FOR CHEMICALLY BONDED PHOSCAST RANGE PLASTIC REFRACTORIES Phoscast-90 XR.) by weight of dry powder. ( covered with plastic sheet or liner) after mixing. Phoscast refractory should never be troweled to obtain smooth surface and the surface should be finished by ramming only. after adding water. For bed coil tube application of AFBC boiler:. MIXING : The Phoscast plastic refractories is supplied in two components system i.5% by weight of liquid binder ( i.75 Kg / 2850 ml ). the dry powder mix and the liquid binder (phosphoric acid). drop it from 6 to 7 feet on floor. 4.5% ( 1750 ml approx. 20 mm.e. The desired lining or repair thickness is built up in several courses while ramming the mass to uniform thickness. using acid proof rubber handgloves. without any effect on properties. If does not break (only flattens from the bottom) indicates that mix is OK. The dry powder packing is of 50 kg each which is to be mixed with 9. For testing make the ball of the material with palm. Now the plastic mass is ready for application after about 10 to 12 minutes of mixing. material must be mixed thoroughly again till homogenous plastic mass is obtained . 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. Finish should be given by pressing the hand palm against material applied. using surgical type thin rubber hand gloves. The Phoscast plastic refractory mix can be applied over a period of 2 hrs. Any excess mass is to be sliced off with trowel edge and then finished by ramming again. Drying and Heating is essential for Phoscast-90 XR refractory. The size of the firewood should be 3” to 4” dia and length approx. 4 feet. . as this is a heat setting refractory. After this refractory layer should be dried by providing halogen lights/ blower heater. : 4 to 5 hours. Gradual Cooling ( ambient) to be done for next 6-8 hours. for smaller size boilers. 6 hours or maximum. the approximate quantity of firewood required is around 20 MT. 6 hours. For drying the refractory. The following curing schedule is recommended for Phoscast plastic refractory : Air Drying minimum 24 hours.CURING : Phoscast refractory hardens adequately after about 12-14 hrs in ambient and then progressively develops strength on heating at elevated temperatures. This will help to dry the surface area speedily Ambient to 200°C @40°C per hour : Hold at 200°C : 200°C to 400°C @ 40°C per hour : Hold at 400°C or max. 5 hours. 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. The bed temperatures were too low at 2nd and 3rd compartments. The ID inlet draft was -140 mmWC. which had exceeded the temperature limit of 485 deg C. The steam temperature before DESH was 506 deg C. but it showed the limitation of ID fan. The ID fan rpm was full open.4%. The steam generation was 43 TPH. The windbox pr was at 583 mmWC and bed ht was at 380 mmWC. It could be in the transient condition. . The O2 level was 10. The free board temperature was at 471 deg C. All the three beds were in operation. The main steam temperature was at 539 deg C. The PA header pressure was 985 mmWC. The ID fan rpm was 45%. . The free board temperature was at 564 deg C. The 3rd compartment damper sealing was found to be good. The ID inlet draft was -56 mmWC. The steam generation was 35. The main steam temperature was at 505 deg C. which is below the temperature limit of 485 deg C. The windbox pr was at 505 mmWC and bed ht was at 338-356 mmWC.5 TPH.22%. The O2 level was 7. The bed temperatures were quite stable and average is 870 deg C. after stabilising the 1st and 2nd compartments. The steam temperature before DESH was 428 deg C.Photo 02: The above shows the performance of the boiler on 2nd February 2014. The bed temperature average is above 875 deg C. anticipating additional load. the generation was not raised further. The steam generation was 40 TPH. The steam temperature before DESH was 445 deg C. The PA lines in the first compartment was kept open. The free board temperature was at 727 deg C.11%. The ID inlet draft was -99 mmWC. . with 2nd and 3rd compartments in operation. The main steam temperature was at 516 deg C. which was below the temperature limit of 485 deg C. The windbox pr was at 525 mmWC and bed ht was at 350 mmWC. The ID fan rpm was 65%. The O2 level was 6. As the TG exhaust temperature was going above 85 deg C.Photo 03: The above shows the performance of the boiler on 24th January 2014.