Heat InputRadiation LossSteam OutputBOILER EFFICIENCYHeat Input is Pulverised CoalHeat Output is Superheated SteamFurnaceSecond PassESP

Efficiency CalculationsStandard Applied :- ASME Standard PTC 4.1Calculation Method :- Loss MethodLosses calculated as percentage of INPUT as 100%

Losses in Boilers 1) Loss due to dry flue gas = 4.928% FurnaceSecond PassESPHeat Input

Losses in Boilers Contd.2) Loss due to Unburnt Carbon = 0.331% FurnaceSecond PassESPHeat Input

Losses in Boilers Contd.FurnaceSecond PassESP3) Due to Sen. Heat of Bottom Ash = 0.071%4) Due to Sen. Heat of Fly Ash = 0.102%Heat Input

Losses in Boilers Contd.FurnaceSecond PassESP 5) Radiation Losses =0.200% Heat Input

Losses Related to Coal & Ambient Air Quality6) Loss due to moisture in Fuel= 1.263% 7) Loss due to Hydrogen in Fuel= 5.537% 8) Loss due to Moisture in Air = 0.074% 9) Unaccounted Losses= 1.327% Total Losses = 13.83%

Data required for Boiler Efficiency CalculationsUnit loadMW FW Flow at Econ inletT/hr Wet bulb Temp0C Dry bulb Temp0C Barometric PressuremmHg Total Coal FlowT/hr Unburnt C in BA% Unburnt C in FA% Radiation & Unaccounted Losses% % Fly ash to Total Ash% % Bottom ash to Total ash%

Data required.2Proximate Analysis of Coal Air Dry As firedMoisture % % Ash % % Volatile Matter % % Fixed Carbon % % Gross Cal. Value Kcal/kg Kcal/kg

Ave FG O2 APH in Ave FG O2 APH Out Ave FG CO2 APH inAve FG CO2 APH Out Ave FG CO APH inAve FG CO APH Out Ave. FG Temp APH inAve. FG Temp APH Out Air to APH in Air APH out Total Primary Flow Total Air Flow LTotal Air Flow R Design Ambient / Ref air Temp

CalculationsUltimate Analysis As fired Basis1. Carbon = (Fixed Carbon AD+0.9(Vol Matter AD-14)) *GCV AF/GCV AD2. Sulphur = 0.4 * GCV AF/GCV AD3. Hydrogen = Vol.Matter AD*(7.35/(Vol Matter AD+10)- 0.013)* GCV AF/GCV AD4. Moisture = Moisture AF5. Nitrogen = (2.1-0.012 * Vol.Matter AD)* GCV AF/GCV AD6. Oxygen = 100-(Carbon+Hydrogen+Nitrogen+Ash AD+Moisture AD)* GCV AF/GCV AD7. Ash = Ash AF and 8. Gross Cal. Value=GCV AF

Calculations .. LossesDry Gas Loss = Sensible heat of dry gas*100/(GCV AF*4.186) %Carbon in fuel%Sulfur in fuel%Carbon in ash / kg of fuelkg/kg coalSpecific Heat of Gaskg/kg CAvg. Flue gas temp - APH Out0CUnburned C in Ash = Pfa/100*Cfa + Pba/100*Cba%C in Ash / Kg of coal =A/100*Cash/(100-Cash)kgTotal air Flow = A+BThrRatio SA Flow to Total Air Flow - Fsa/Fta%Ratio PA Flow to Total Air Flow = Fpa/Fta%Weighted Temp Air In = Tsai*Rsa+Tpai*Rpa0CWeighted Temp Air Out = Tsao*Rsa+Tpao*Rpa0CAvg. Flue Gas CO2 -APH Out%Gross CVkcal/kgWeight of Dry Gas = (Ca+S/2.67-100*U)/(12*CO2out)kg/kg coalSensible Heat Dry Gas = Wd*30.6(Tgo-Trai)kJ/kg

CONTROLLABLE LOSSES 1FOLLOWING LOSSES CAN BE CONTROLLED1. LOSS DUE TO DRY FLUE GASTHE DESIGNER GIVES THIS LOSS AT THE FLUE GAS APH OUTLET TEMP OF 1400CANY INCREASE IN THE FGT MORE THAN 1400C WILL BE RESULTING IN MORE LOSSES. THIS TEMP HAS TO BE CONTROLLED BY PROPER CLEANING OF THE FURNACE

CONTROLLABLE LOSSES 2aLOSSES DUE TO THE UNBURNT COAL IN BOTTOM AND FLY ASH.LOSS DUE TO UNBURNT IN BOTTOM ASHTHE DESIGNER GIVES THIS %AGE AS MAX 4.8 % ANY INCREASE IN THIS PERCENTAGE BEYOND THIS WILL RESULT IN MORE LOSSESIF UNBURNT IN BOTTOM ASH IS MORE, THE CULPRIT IS THE COAL MILL, CHECK THE FINENESS OF PULVERISED COAL. CHECK THE % RETENTION ON 50 MESH. IT SHALL NOT EXCEED 1%.

CONTROLLABLE LOSSES 2bCHECK THE UNBURNT IN FLY ASH SAMPLE TAKEN FROM THE FIRST HOPPER OF ESP/BFAS PER THE DESIGNER IT SHALL NOT EXCEED 0.8%.IF UNBURNT IN FLY ASH EXCEEDS 0.8% IT INDICATES INCOMPLETE COMBUSTION DUE TO LESS AMOUNT OF AIRCHECK FOR O2 % AT THE APH FG INLET FOR 2.8%, INCREASE IF NECESSORY TO 3.2%. AGAIN CHECK FOR UNBURNTS IN FLY ASH. SIMULTANIOUSLY CHECK FOR AIR LEAKAGES/INGRESS IN THE SECOND PASS

Losses CalculationsAssumptions:- Fly Ash is 80% of Total Ash.Bottom Ash is 20% of Total AshSulphur is 0.4% in Coal

DATA REQUIREDFuel Properties Proximate Analysis of CoalAir Dry BasisAs Fired basisMoisture %Moisture % Ash % Ash %Volatile Matter %Volatile Matter %Fixed Carbon %Fixed Carbon %Gross Cal. Value %Gross Cal. Value %

Data Required contd.Unit load MWFW Flow at Econ inletT/hrWet bulb Temp0CDry BulbTemp 0CBarometric PressureTotal Coal FlowT/hrUnburnt Carbon in BA%Unburnt Carbon in FA%

Data Required Contd.** Ave FG O2 APH in ** Ave FG CO2 APH in** Ave FG CO APH in ** Ave FG O2 APH Out** Ave FG CO2 APH Out ** Ave FG CO APH Out** Air to APH in Temp ** Air APH out Temp** Total Air Flow L** Total Air Flow R** Ave. FG Temp APH in** Ave. FG Temp APH Out** Total Primary Air Flow

GCV Calculations for CoalCalculations of GCVAs fired BasisCoal sample is taken as received basis, heated for calculation of A) Total Moisture content = TM%Air Dry BasisThe sample is air dried for removal of surface moisture and burned completely for A) Inherent moisture content = M %B) Ash percentage = A %

GCV Calculations for Coal Contd.1) Useful Heat Value= 8900 138(A%+M%) kcal/kg2) Gross Calorific Value= (UHV + 3645 75.4 M%)/1.466 (Air Dry Basis) Kcal/kg3) Ash % (As fired basis)= [A %] (100 - TM%)/(100 M%) %4) Gross Calorific Value= [GCVAD] (100 - TM%)/(100 M%) (As fired Basis) Kcal/kg5) Net Calorific Value= [GCV] 10.02M% Kcal/kg

CalculationsWeight of Dry Gas = (Ca+S/2.67-100*U)/(12*CO2out)Ca = % Carbon in fuel (Ultimate Analysis as Fired)S = % Sulfur in fuel (Ultimate Analysis as Fired)A = % of Ash in fuel (Ultimate Analysis as Fired)Unburned C in Ash = Pfa/100*Cfa + Pba/100*CbaU = Carbon in ash / kg of fuel=A/100*Cash/(100-Cash)CO2 Out = Avg. CO2 Flue Gas -APH OutSensible Heat Dry Gas = Wd*30.6(Tgo-Trai)