CORRECTION FACTORS for BOILER EFFICIENCY CALCULATION

Interesting Facts

  1. Bagasse GCV @50%- 2272 kcal/kg or 2300 kcal/kg a RARE Phenomena but Dominant for Bagasse Fired Boiler Design & Guaranteed Efficiency Calculation
  2. Normally, CUSTOMER DOES NOT RECEIVE any Contractual Guaranteed Boiler Efficiency Detailed Calculation BUT all CORRECTION are applied on the basis of these calculations only

MAIN FAVOURABLE Correction:

  1. Fuel Hydrogen % Content
  2. Fuel Moisture % Content
  3. Fuel GCV
  4. APH GAS Outlet temperature (Least preferable)
  5. ESP Outlet/Chimney Inlet Gas temperature
  6. Relative Humidity & Air Density
  7. Ambient Air Inlet temperature BUT Efficiency Calculation done on air Inlet temperature after Fan Rise Consideration OR SCAPH Outlet
  8. Fuel Oxygen % Content
  9. Fuel Ash % Content
  10. Fuel Sulphur % Content
  11. Fuel- Fixed Carbon/Volatile Matter Ratio
  12. Limestone Size and Reactivity
  13. Economiser Inlet Water Temperature and relatively Steam Flow correction

NORMALLY AVOIDED Correction:

  1. Ash Unburnt Carbon
  2. Radiation Loss
  3. Deaerator Outlet Water Temperature
  4. Excess Air
  5. Flue Gas Volumetric Flow Rate w.r.t. temperature for Power
  6. Consumption & Change in Velocity
  7. Change in APH Gas Outlet Temperature due to variation in economiser Inlet Water temperature
  8. Change in Auxiliary Power Consumption due to variation in Ambient Air temperature, Particle size distribution

NORMALLY IGNORED:

  1. Attemperator Spray Water Quantity (to Achieve Final Steam Temperature)
  2. Economiser outlet Feed water temperature
  3. Air Pre-Heater (APH) Air outlet temperature
  4. Change in Air Distribution Ratio in Primary vs Secondary

For detailed procedure to plot efficiency correction curve, Please see the attachment

Essential Input Required for Correction Curve is Contractual Guaranteed Boiler Efficiency Detailed Calculation

Efficiency Loss % due to 3.10% Hydrogen in Fuel e.g. 3.80% loss Correction Curve Calculation: Variation/Correction for 4.20% Hydrogen= 4.20*(3.80/3.10) = 5.15% loss, Net correction applied = 5.15% - 3.80% = 1.35%

Efficiency Loss % Dry Gas at 180 degC APH Gas Outlet Temperature e.g. 9.1% loss and Dry Gas produced 2580 Kg/Mcal and 33 degC ambient temperature Correction Curve Calculation: Variation/Correction in dry gas loss for 200 degC APH Gas Outlet Temperature, dry gas produced 2580 kg/Mcal and 33 degC ambient temperature = 2580*Specific heat of flue gas constant like 0.24 *(200 - 33) = 10.34% loss, Net correction applied = 10.34% - 9.10% = 1.24%

A CORRECT OBSERVATION will SAVE ENERGY & COST