630 DEG C secondary reheating unit thermodynamic system and optimization method thereof

Abstract

The invention provides a 630 DEG C secondary reheating unit thermodynamic system with a boiler; an ultrahigh pressure cylinder, a high pressure cylinder and a medium pressure cylinder are arranged onone side of the boiler in a communicating mode. A low-pressure cylinder is arranged on one side of the medium-pressure cylinder in a communicating manner; one side of the ultrahigh pressure cylinder is communicated with a steam turbine; the steam turbine is communicated with the high-pressure cylinder; one side of the steam turbine is communicated with a high-pressure heater; the high-pressure heater is respectively communicated with the boiler and the ultrahigh-pressure cylinder; a condenser is arranged on one side of the low-pressure cylinder in a communicating mode. One side of the condenser is communicated with a low-pressure heater; the low-pressure heater is respectively communicated with the low-pressure cylinder and the medium-pressure cylinder; a first water pump is connected between the condenser and the low pressure heater, and a third water pump is connected with the medium pressure cylinder. According to the thermodynamic system, irreversible losses caused by the too largeheat exchange temperature difference in the heaters can be reduced, the cost can be reduced, and the safety and reliability of the unit are improved.

Description

Technical field [0001] The invention belongs to the technical field of thermal power generation, and particularly relates to a thermal system of a 630°C secondary reheat unit and an optimization method thereof. Background technique [0002] At present, for the 1000MW secondary reheat unit with parameters of 35MPa / 615℃ / 630℃ / 630℃, due to the high temperature of reheated steam, the superheat of each stage of extraction steam after reheating is greatly increased, and the corresponding regenerative heater The internal heat exchange temperature difference increases and the irreversible loss increases, which weakens the benefits of improving steam parameters. The higher the steam parameter, the more prominent this contradiction. The conventional engineering approach is to add an external steam cooler to the part of the regenerative extraction steam after reheating to appropriately reduce the superheat of the regenerative extraction steam. [0003] However, as the initial temperature and ...

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Problems solved by technology

[0003] However, with the increase of the initial temperature and reheat temperature, the extraction temperature also increases. The external steam cooler and some high-pressure heaters need to use materials suitable for higher temperature grades, and the cost will increase significantly. Therefore, we will provide another A thermal system of a 630°C double reheat unit and its optimization method can not only reduce the irreversible loss caused by the excessive heat exchange temperature difference in the high pressure heater or low pressure heater, but also reduce the cost and improve the safety and reliability of the unit sex

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