Secondary reheating steam turbine generator unit system provided with overheating steam feed water heater

Abstract

The invention provides a secondary reheating steam turbine generator unit system provided with an overheating steam feed water heater. The secondary reheating steam turbine generator unit system comprises a boiler, a steam turbine, a generator, a first reheater, a second reheater, a feed water heater group, and an overheating steam feed water heater, wherein the steam turbine comprises a high pressure cylinder, a first intermediate pressure cylinder, a second intermediate pressure cylinder and a low pressure cylinder, wherein the high pressure cylinder is connected with the outlet of the boiler; the first reheater is arranged in the boiler and connected between the high pressure cylinder and the first intermediate pressure cylinder; the second reheater is arranged in the boiler and connected between the first intermediate pressure cylinder and the second intermediate pressure cylinder; the feed water heater group is connected with the steam turbine; and the overheating steam feed water heater is connected between the feed water heater group and the inlet of the boiler. According to the invention, through the overheating steam feed water heater on a feed water system, the feed water temperature is improved by overheating degree of extracted stream, so that the heat efficiency of a secondary reheating steam turbine generator unit can be improved.

Description

technical field [0001] The invention relates to a turbogenerator system, in particular to a twice-reheating turbogenerator system with a superheated steam feed water heater. Background technique [0002] According to the theory of steam turbine reheating cycle in thermal power plants, increasing the temperature of boiler feed water can improve the thermal efficiency of twice reheated turbogenerator units, and theoretically there is an optimal feed water temperature. In the double-reheat turbo-generator set, the exhaust steam is heated by the boiler through the two-time steam turbine, and then returns to the steam turbine-turbine to do work. Usually, the exhaust steam from the high-pressure cylinder of the steam turbine enters the boiler to heat the reheater I and then re-enters the first medium-pressure cylinder of the steam turbine to perform work. Press the cylinder to do work. Among them, the high-pressure cylinder, as a part of the double-reheat steam turbine unit, rec...

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Problems solved by technology

Such a system improves the heat exchange efficiency of the heat exchanger and reduces the cost of the heat exchanger, but it also has the following disadvantages: Since the existing two-time reheat unit is a multi-stage heat recovery system, the feed water is heated at each stage It is heated step by step in the heater, and the extraction steam will condense into water in the feed water heater, so the feed water temperature at the outlet of the feed water heater is limited by the saturation temperature corresponding to the extraction steam pressure

As a result, existing feedwater heaters are limited in their ability to heat the feedwater

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