Evaporation ratio (ER)
It is the ratio of amount of steam generated per unit amount of fuel burned. ER generally considered as a performance evaluation parameter for boiler. Evaporation ratio is depending upon quality of coal used.
Turbine heat rate
Heat rate is the term used in power plant to express Rankine cycle or thermal efficiency of power plant.Rankine cycles are modified as Reheat Rankine and Regenerative Rankine for increasing efficiency of cycle i.e, to decrease cycle heat rate,less is the heat rate better is the performance.Heat rate is expressed as Kcal/Kwh. Turbine heat rate is the ratio of total energy or enthalpy used in turbine (Kcal) divided by electrical power generated by turbine(Kwh).For extraction cum condensing turbine ,
turbine heat rate is classified as gross turbine heat rate and net turbine heat rate.
Gross turbine heat rate
Gross turbine heat rate is defined as amount of heat added to water from feed water inlet to economiser up to steam outlet at Main steam stop valve per unit power output of turbine.
Net turbine heat rate
Net turbine heat rate is nearly similar to gross heat rate except in net turbine heat rate power consumption of boiler feed water pump is subtracted from the power output of generator.
Gross Plant heat rate
Net plant heat rate
% Auxiliary power consumption
Auxiliary power consumption is the amount of power consumed by various auxiliary equipments like fans,pump etc.in power plant for generating full capacity of power output from turbine. Generally value of percentage auxiliary power consumption should be 10-12 %.
Specific steam consumption
Amount of steam consumed by turbine per unit of power generated.
Specific fuel consumption
Specific fuel consumption is the amount of fuel consumed by boiler per unit of power generated
Blowdown percentage
Due to continues evaporation of water in boiler TDS level in water increases and to maintain proper amount of TDS level in boiler need to replace some amount of boiler water with fresh water.
Excess air percentage
Fuel requires air for combustion, the exact amount of air required for combustion is called as theoretical amount of air required for combustion but there may be possibility of not completing combustion in practical scenario, so for ensuring complete conversion of carbon in to carbon dioxide at the end of combustion reaction some extra amount of air is supplied is known as Excess air .
Where, 21 is the amount of oxygen present in air by weight.
Gross calorific value (GCV)
Amount of heat generated by complete combustion of fuel per kg of fuel burnt.It is expressed in terms of Kcal/kg for solid and liquid fuels and Kcal/m3 for gaseous fuels.
For more informative topics visit,
questions-asked-in-boiler-operation-engineer-interview
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It is the ratio of amount of steam generated per unit amount of fuel burned. ER generally considered as a performance evaluation parameter for boiler. Evaporation ratio is depending upon quality of coal used.
| Evaporation ratio | Amount of steam generated | |||||
| = | ||||||
| Amount of Fuel burnt | ||||||
Heat rate is the term used in power plant to express Rankine cycle or thermal efficiency of power plant.Rankine cycles are modified as Reheat Rankine and Regenerative Rankine for increasing efficiency of cycle i.e, to decrease cycle heat rate,less is the heat rate better is the performance.Heat rate is expressed as Kcal/Kwh. Turbine heat rate is the ratio of total energy or enthalpy used in turbine (Kcal) divided by electrical power generated by turbine(Kwh).For extraction cum condensing turbine ,
turbine heat rate is classified as gross turbine heat rate and net turbine heat rate.
Gross turbine heat rate
Gross turbine heat rate is defined as amount of heat added to water from feed water inlet to economiser up to steam outlet at Main steam stop valve per unit power output of turbine.
Net turbine heat rate
Net turbine heat rate is nearly similar to gross heat rate except in net turbine heat rate power consumption of boiler feed water pump is subtracted from the power output of generator.
Gross Plant heat rate
Gross plant heat rate is the amount of total energy added to boiler by burning coal per unit amount of power generated by generator. Gross Plant heat rate considers only losses in steam generator and turbine.
Net plant heat rate
Net plant heat rate is same as Gross plant heat rate except in net plant heat rate we consider amount of auxiliary power consumption of plant. Net plant heat rate considers losses and inefficiencies in auxiliary power consumption of plant.
Auxiliary power consumption is the amount of power consumed by various auxiliary equipments like fans,pump etc.in power plant for generating full capacity of power output from turbine. Generally value of percentage auxiliary power consumption should be 10-12 %.
Specific steam consumption
Amount of steam consumed by turbine per unit of power generated.
Specific fuel consumption
Specific fuel consumption is the amount of fuel consumed by boiler per unit of power generated
Blowdown percentage
Due to continues evaporation of water in boiler TDS level in water increases and to maintain proper amount of TDS level in boiler need to replace some amount of boiler water with fresh water.
| Blowdown percentage | Feed water flow - steam generation | |||||
| = | ||||||
| Feed water flow | ||||||
Excess air percentage
Fuel requires air for combustion, the exact amount of air required for combustion is called as theoretical amount of air required for combustion but there may be possibility of not completing combustion in practical scenario, so for ensuring complete conversion of carbon in to carbon dioxide at the end of combustion reaction some extra amount of air is supplied is known as Excess air .
| Excess air | Oxygen in flue gas | |||||
| = | ||||||
| 21 - oxygen in flue gas | ||||||
Where, 21 is the amount of oxygen present in air by weight.
Gross calorific value (GCV)
Amount of heat generated by complete combustion of fuel per kg of fuel burnt.It is expressed in terms of Kcal/kg for solid and liquid fuels and Kcal/m3 for gaseous fuels.
For more informative topics visit,
questions-asked-in-boiler-operation-engineer-interview
How-small-ignorance-could-cause-fire-in-APH-of-boiler-and-preventive-measures
understand-stages-in-commissioning-of-boiler
Easily-understand-mechanisms-and-cause-of-boiler-tube-failure
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