METHOD FOR OPERATION OF A COMBINED GAS AND STEAM UNIT OF A POWER PLANT Russian patent published in 2022 - 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, wherein atmospheric air is supplied to the turbocharger of a gas turbine and compressed therein to the required pressure; the air compressed in the turbocharger is divided into primary air and secondary air; organic fuel, primary air, and desalinated water are supplied into the combustion chamber of the gas turbine unit; the process of combustion of organic fuel is executed in the combustion chamber, forming combustion products heated to a high temperature, as well as evaporation of the desalinated water; the products of combustion of the organic fuel and water vapour are mixed with the secondary air; the resulting gas-vapour mixture is directed into the gas turbine; in the gas turbine, the process of expansion of the gas-vapour mixture is executed and the work of the gas turbine cycle required to drive the turbocharger and the electric generator is performed; the gas-vapour mixture spent in the gas turbine is directed to a waste heat boiler, wherein water vapour is generated in the process of cooling the gas-vapour mixture; the water vapour is supplied to the steam turbine, and the waste gases are discharged into a waste heat exchanger; in the steam turbine, the process of expansion of the water vapour is executed and the useful work of the steam power cycle required to drive the electric generator is performed; the water vapour spent in the steam turbine is discharged into the condenser, wherein condensation of the water vapour is performed in the process of heat exchange with the circulating water; in the waste heat exchanger, in the process of heat exchange with the circulating water, the waste gases are cooled below the dew point with the condensation of part of the contained water vapour; the desalinated water released through the condensation of water vapour from the waste gases is directed to the container tank through the condensate collector with a hydraulic seal and therefrom supplied by a pump via a stainless steel pressure main into the combustion chamber of the gas turbine unit; the circulating water heated in the condenser and the waste heat exchanger is supplied to the exhaust tower of the cooling tower by a circulation pump via the discharge pressure main, wherein the circulating water is cooled by atmospheric air in the process of heat and mass transfer in direct contact therewith, and discharged into the water collector; the waste gases after the waste heat exchanger are discharged into the atmosphere, and natural gas is used as organic fuel, wherein a stainless steel recuperative heat exchanger is additionally installed in the gas duct after the waste heat boiler before the waste heat exchanger, and the desalinated water is heated therein to a temperature of 90–100°C, directed into the combustion chamber of the gas turbine unit and released in the waste heat exchanger from waste gases at a temperature of 32–35°C, with a stream of waste gases cooled from 100–110°C to a temperature of 50–55°C exceeding the dew point 38–45°C by 10–12°C, wherein the change in the flow rate of waste gases directed into the recuperative heat exchanger is implemented by the control body installed in a bypass gas duct of the recuperative heat exchanger.

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

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