METHOD FOR OPERATION OF A COMBINED GAS AND STEAM UNIT OF A POWER PLANT Russian patent published in 2021 - IPC F01K23/10 

FIELD: power engineering.

SUBSTANCE: invention relates to power engineering and can be used in thermal power plants. Proposed is a method for operation of a combined gas and steam unit of a power plant, according whereto, organic fuel and atmospheric air compressed in a turbine compressor are supplied into the combustion chamber of the gas turbine unit, wherein the process of combustion of the organic fuel is executed forming combustion products heated to a high temperature, the combustion products are mixed with the secondary air, the resulting gases are directed into the gas turbine, the process of gas expansion is executed in the gas turbine and the work of the gas turbine cycle, required to drive the turbine compressor and the electric generator, is performed, the gases spent in the gas turbine are directed to a waste heat boiler, located wherein are a primary heat exchange surface, an additional fuel combustion chamber, and an intermediate steam superheater, water vapour is generated in the waste heat boiler in the process of gas cooling in the primary heat exchange surface, water vapour is supplied to a condensation-type steam turbine consisting of a high-pressure cylinder and a low-pressure cylinder, the process of water vapour expansion is executed in the steam turbine and the useful work of the steam power cycle, required to drive the electric generator, is performed, wherein intermediate superheating of the water vapour spent in the high-pressure cylinder of the condensing-type steam turbine is executed in the intermediate steam superheater, the water vapour spent in the steam turbine is directed to a condenser, and the gases cooled in the intermediate steam superheater are discharged to the atmosphere through an exhaust gas duct, the water vapour is condensed in the condenser in the process of heat exchange with circulation water, the condensate formed in the condenser is pumped into the waste heat boiler, wherein the total flow of exhaust gases cooled in the primary heat exchange surface is divided into two flows, the first gas flow in the amount of 70 to 75% at a temperature of 100 to 120°C is directed into the exhaust gas duct, and the second gas flow in the amount of 25 to 30% is supplied to the dedicated gas duct in the tail section of the waste heat boiler, wherein a regulating body, an additional fuel combustion chamber and heat exchange surfaces of the intermediate steam superheater and network water gas heater are installed sequentially in the direction of gas flow, wherein the gases are heated in the additional fuel combustion chamber and cooled in the heat exchange surfaces of the intermediate steam superheater and network water gas heater, the gases cooled in the heat exchange surface of network water gas heater to a temperature of 80 to 90°C are directed to the exhaust gas duct, mixed therein with the first flow of gases cooled in the primary heat exchange surface, the total gas flow at a temperature of 90 to 110°C is discharged into the atmosphere, also, the flow rate of the second gas flow directed to the dedicated gas duct is changed by the regulating body installed before the additional fuel combustion chamber.

EFFECT: increase in the reliability and cost efficiency of operation of the combined gas and steam unit of a power plant.

1 cl, 1 dwg