Cogeneration Plants - Energy Conversion and Management - page 139

Table 9.1 Technical parameters of generation power plants fed by natural gas, solid biomass,
liquid biomass, and standard coal

DG¼distributed
generation;
UP¼utility plant

Electrical
efficiency (%)

Heat recovery
efficiency (%) Technology Fuel

Reciprocating
engine

35-45 % 45-35 % Natural gas DG

Gas turbine 25-35 % 55-45 % Natural gas DG

Micro gas
turbine

18-20 % 62-60 % Natural gas DG

Boiler and
backpressure
steam turbine

12-20 % 68-60 % Natural gas DG

Boiler and
backpressure
steam turbine

15 % 65 % Solid Biomass DG

Reciprocating
engine

35-40 % 45-40 % Liquid Biomass DG

Utility plant
combined cycle
800-1,000 MW

60 % 0 Natural gas UP

Utility plant,
steam condensing
turbine

26 % 0 Coal UP

NOT RECOVERABLE HEAT

COMBUSTION AIR

LOSSES

COGENERATION PLANT

ELECTRIC GENERATOR

NATURAL GAS

ELECTRICAL ENERGY

LOSSES

HEAT RECOVERY

100% F 40% H 40% E 20% L

50% Net heat recovery index (1)
30.8% Primary Energy Saving index(2)

2,500 kW 1,000 kW 1,000 kW 500 kW

104.9 Sm 3 /h

(3)

3 3 3

262.2 Sm /h 116.5 Sm /h ( = 145.7 Sm /h

3

Sm /kWh

0.146

input data
(1) H/(H+E) (2) (1-F/(E/ p +H/ b ))*100

(4)= (3)/ b where h p =electrical production and transmission efficiency=40% and h b =efficiency of the boiler to replace=90%

natural gas LHV=34,325 kJ/Sm 3

Fig. 9.1 Basic scheme of a cogeneration plant