Boiler Efficiency Evaluation Efficiency Facts

• Combustion Efficiency (Burner)

• Heat Transfer Efficiency (Surface area)

• Boiler Efficiency (Total System Efficiency)

Boiler Efficiency

Shell Losses 2%

AshUnburnts 2%

Boiler Efficiency=75%Fuel 100%

Stea

m 7

5%

Flue

Gas

es 1

8%Blow Down 3%

Efficiency Evaluation Method

Direct Method• Measurement of

steam & Fuel flow only

• Approximate Result

Indirect Method• Measurement of

Temp, Pr, Fuel/Flue gas analysis,

• More accurate result

• Heat Loss Method• ASME/IS

DIRECT METHOD

Boiler Efficiency = Output X 100 Input

= (Steam Flow) X (Steam Enthapy- F W Enthalpy) ------------------------------------------------------------------

(Fuel Flow X GCV) OR

Boiler Efficiency =Evap.Ratio X Steam Enthalpy

GCV

INDIRECT METHOD(As per IS: 8753)

Various Boiler LossesVarious Boiler Losses

1.1. Heat Loss in Dry Flue GasesHeat Loss in Dry Flue Gases2.2. Heat Loss Due to Moisture and Hydrogen in the Heat Loss Due to Moisture and Hydrogen in the

Fuel Fuel 3.3. Heat Loss Due to Moisture in the AirHeat Loss Due to Moisture in the Air4.4. Heat Loss Due to Carbonmonoxide in Flue GasesHeat Loss Due to Carbonmonoxide in Flue Gases5.5. Surface Heat Loss Due to RadiationSurface Heat Loss Due to Radiation6.6. Blowdown LossesBlowdown Losses

CONTROLLABLE & UNCONTROLLABLE LOSSES

Boundary barrier Balance

Fueltank

Boiler400kg/hr30.c

30.c

APH

5200kg/hr,120 .c

320.c

stackSteamprocess

water520 kg.hr

179.c

4680kg/hr

10% makeup water

Measurements required for thermal energy Audit in Boiler

Fuel flow, steam/water flow

Temp & Pressure of steam

Temperature of water inlet / outlet of economizer

Draught

CO2, O2, CO , Temperature from Flue Gas

Surface Temp & Ambient Temp

Surface Area, m2

Size & dimension of boiler

Test Procedure • Plan / inform the concerned dept.

• All the Instrument should be calibrated • Ensure fuel and water availability• Test at maximum steam load condition• Conduct 8 hrs minimum (1/2 or 1 hr frequently)• Water level in drum should be same at start &

end of test• Gas Sampling point should be proper• No blow down during test

Requirements in boiler

• Oil level in tank• Water level in Service Tank • No leakage water• No blow down• Boiler Testing Sheet• Fuel Analysis Report• Boiler Technical Specifications

Fyrite kit

CO2, O2 in flue gases

Combustion analysers

Contact thermometer

Infrared thermometer

RPM measurement

Tachometer Stroboscope

Date : 8/2/2001Time Fuel ID PA SA ID PA SA O2 CO CO2 Temp Temp

Feederrpm KW

11:00 21 100% 40% 50% 22 8 1.9 14.2 307 5.1 125 29AM

11.30 30 50% 20% 30% 20.6 6.96 1.9 9.8 16 8.3 126 30AM

* At normal operatiing condition, power and flue gas measurement were taken Then, excess air reduced by closing damper in all FD and ID secondary air fan Fuel feeding rate is increased from 21 rpm to 30 rpm Again power and flue gas measurement were taken

Suggesions : 1) Keep furnace draft + 5mm 2) Flue gas should be light gray at chimny top

3) keep Lowest possible damper position

opening)(Power management) (Flue gas analysis)

BOILER PERFORMANCE TESTING

Steam Pressure - 5 to 7 kg/cm2

(Damper position

Boiler Calculations