Understanding the specific terms for Power plants performance analysis

It is very must to understand the basic fundas of specific terms used in power plants.

The following terms very frequently used in power plant calculations

1-SFR:It is steam to fuel ratio, it is the amount of steam generated on burning or oxidation of 1 MT of fuel. 

SFR =Steam generated / Fuel consumed

Note:If steam generated is taken in MT, then take fuel conssumed also in MT  , so the SFR is unitless

SFR depends on 

• Type of the fuel & its GCV
• Type of the Boiler & its efficiency

If the fuel GCV & Boilr efficiency are high,then SFR value will be more and vice versa

2-SSC: Spcific steam consumption, it is the amount of steam required to generate 1 Kwh or 1Mwh of power.

SSC = Steam consumption / Power generated

Note: If steam consumption taken is in MT,then power generation should be in MW.And if steam consumption taken is in Kg,then power generation should be in Kw.

SSC depends on the type of steam Turbine & its operating parameters.

• If the turbine has lesser number or no any extractions or bleeding steam, then the SSC value of that particular turbine will be less
• 
  
• If the steam pressure and temperature at the Turbine inlet are more than the SSC value is less

Boiler calculations for BOE exam

3-SFC:It is the amount of fuel consumed to generate one Kwh of power

SFC = Fuel consumed in MT or Kg / Power generated in Mwh or Kwh

SFC is also give as,

SFC = SSC / SFR

SFC is less for power plants which have,

• Higher Boiler efficiency
• Higher fuel GCV
• Higher steam pressure & tempeatures
• Condensing turbines 

CALCULATION OF POWER PLANT EQUIPMENTS EFFICIENCY

4-PLF: Plant Load Factor, it is the ratio of average power generation to the plant capacity during that period. It is expressed in %.

PLF = (Average power generation X 100) / Plant capacity during particular period.

5-PCF: Plant Capacity Factor is the ratio of average power generation to the plant installed capacity. It is expressed in %.

PCF = (Average power generation X 100)/Plant installed capacity.

6-PAF:Plant Availability Factor ,it is the ratio of total time in hours utilized for power generation to the total available hours for power generation. It is expressed in %.

PAF = (Total hours utilized for power generation X100)/Total available hours

Basics of Thermodynamics

7-Demand Factor:It is the ratio of maximum demand to the total connected load. It is always less than unity. Lower the demand factor, the less system capacity required to serve the connected load.

8-Diversity Factor: It is  the ratio of total connected load to the maximum demand. It is always greater than unity.

Let us solve follwoing examples to be more clear on above specific terms.

Example-1:A Coal fired Boiler of capacity 75 TPH, generates 1680 MT of steam in a day at SFR 2.2, calculate the fuel consumed

SFR = Steam generation / Fuel consumed

Fuel consumed = 1680/2.2

Fuel consumed = 763.63 MT

Example-2:A cogneration based 25 MW steam Turbine has specific steam consumption (SSC) 5.5 MT, calculate the steam flow per hour

SSC = Steam consumed / Power generation

Steam consumed = 5.5 X 25 =137.5 MT/hour =137.5 TPH

Example-3: A Therml power plant generates 2000 MW power in a consumes 1230 MT coal and generates 8000 MT of steam, calculate SFR, SSC & SFC of the thermal power plant

SFR =Steam generated / Fuel consumed

SFR = 8000 / 1230 = 6.5

SSC = Steam consumed / Power generation

SSC = 8000 / 2000 =4.0 MT of steam / MW of power

SFC = Fuel consumed in MT or Kg / Power generated in Mwh or Kwh

SFC = 1230 / 2000 = 0.615 kg of coal / kwh of power generated

or 

SFC = SSC / SFR = 4.0 / 6.5 =0.615 kg of coal / kwh of power generated

Example-4:Power generation of 70 MW power plant is restricted to 45 MW due to fuel constraint, calculate the PLF and PCF if average generation of the plant in day is 42.5 MWH.

Plant load factor (PLF) = (Average power generation in a day) X 100/(Plant capacity on particular period)
                                      =(42.5 X 100/45) = 94.4%
Plant capacity factor (PCF) = (Average power generation in a day) X100/(Plant installed capacity)
                                             = (42.5 X 100/70) =60.7%

Example-5:A power station has a connected load of 50 MW, the maximum demand at the station is 25 MW. Find the demand factor.
Demand factor (DF) = Maximum demand/Connected load
                                  = 25/50 =0.5

Example-6: A power plant runs 365 days in a year, but due to major breakdown in Turbine, plant taken sshutdown for 2days, calculate the plant availability factor

PAF = (Total hours utilized for power generation X100)/Total available hours

PAF = (365-2) X 24 X 100 / (365 X 24)
PAF = 99.45%

PAF can also be calculated by considering the days

        Opportunities for energy conservation in power plant