POWER PLANT WITH BUILT-IN PRE-HEATING OF FUEL GAS Russian patent published in 2016 - IPC F01K7/16 

FIELD: electricity.

SUBSTANCE: invention relates to a combined cycle power plant with pre-heating of fuel gas and to a method of energy production using the said power plant. Said power plant comprises gas turbine (6), a water-steam cycle with steam turbine (13), waste heat boiler (9) with at least two levels of pressure and fuel heater (2) for pre-heating of fuel (18) of gas turbine (6). Water-steam cycle contains a low pressure level, a medium-pressure level and a high pressure level. First heat exchanger (20) of fuel heater for preheating of fuel gas (17) is connected to the output of low-pressure economiser (32) or to the outlet of medium pressure economiser (31). Fuel heater (2) includes first heat exchanger (20) for pre-heating of fuel gas (17) to the first high temperature, which is connected to line (38) of feed water, in which the pressure provided by waste heat boiler (9) is lower than the highest pressure level of the waste heat boiler, for feed water supply to first heat exchanger (20), and second heat exchanger (21) for additional heating of fuel gas (18) to the second high temperature, which is connected to high-pressure feed water line (36) in which there is ensured the highest level of waste heat boiler (9) for supply of high-pressure feed water to second heat exchanger (21). Outlet of second heat exchanger (21) is connected to one of the following: input of intermediate pressure drum (28), or input of low pressure drum (29), or input of high-pressure economiser (30), or the middle part of the high-pressure economiser (30). Power plant comprises expansion tank (42) connected to water outlet of second heat exchanger (21), wherein water outlet of expansion tank (42) is connected to feed water line of the water-steam cycle and steam outlet of expansion tank (42) is connected to steam turbine (13) via steam line (46) from the expansion tank.

EFFECT: there is ensured efficient use of heat of a water-steam cycle and achieved high efficiency of the power plant with minimum power losses.

11 cl, 7 dwg