Flue gas waste heat based dual-pressure power generation system

Abstract

The invention discloses a flue gas waste heat based dual-pressure power generation system, which is used for power generation by utilizing flue gas waste heat and can be used for further increasing the heat utilization rate of flue gas. The flue gas waste heat based dual-pressure power generation system comprises a power generation system consisting of a waste heat boiler, a steam turbine and a deaerator, wherein a flue gas inlet and a flue gas outlet are arranged on the waste heat boiler; a high-pressure heat exchange device and a low-pressure heat exchange device are sequentially arranged from the flue gas inlet to the flue gas outlet in the waste heat boiler; the high-pressure outlet of the high-pressure heat exchange device is communicated with the steam turbine; the high-pressure inlet of the high-pressure heat exchange device is communicated with a water supply hole of the deareator; the low-pressure outlet of the low-pressure heat exchange device is communicated with the steam inlet of the deaerator; the low-pressure inlet of the low-pressure heat exchange device is communicated with the water supply hole of the deaerator; a steam lead-out pipeline is arranged in the power generation system; and the steam lead-out pipeline is arranged on a pipeline between the low-pressure outlet of the low-pressure heat exchange device and the steam inlet of the deareator. According to the invention, the intensity of the steam turbine can be increased, and the heat of the flue gas can also be effectively utilized.

Description

technical field [0001] The invention relates to a power generation system, in particular to a flue gas waste heat dual-pressure power generation system which utilizes flue gas waste heat to generate electricity. Background technique [0002] At present, the system that utilizes waste heat of flue gas to generate electricity mainly includes a waste heat boiler, a steam turbine and a deaerator. . Its working principle is: the cold water deoxidized by the deaerator is sent to the high-pressure heat exchange device and the low-pressure heat exchange device; the high-temperature flue gas enters the waste heat boiler from the flue gas inlet and exchanges with the high-pressure heat exchange device and the low-pressure heat exchange device. Heat, the high-pressure steam generated by the high-pressure heat exchange device is used to send to the steam turbine for power generation. After the power generation is completed, the steam is condensed into cold water through the condenser a...

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Problems solved by technology

[0003] 1. In the existing power generation system, a part of the steam is extracted for use in other places in the industry that need heat supply, but when the steam is extracted, the steam extraction pipeline is set between the outlet of the high-pressure heat exchange device and the steam turbine. Part of the steam is high-grade superheated steam. Although the amount can be reduced, the high-grade superheated steam is used for heating, which reduces the heat utilization efficiency of the entire system. The load of the steam turbine needs to be set sufficiently large, which leads to the reduction of the strength of the steam turbine cylinder equipment

[0004] 2. When the low-pressure steam or hot water generated by the low-pressure heat exchange device is used to return to the deaerator for deaerator operation, since the steam or hot water needs to circulate between the low-pressure heat exchange device and the deaerator, the steam Or hot water will not be discharged. When the temperature of steam or hot water reaches a certain level, it will no longer exchange heat with the flue gas in the waste heat boiler, resulting in a low heat utilization rate for the flue gas; In the low-pressure heat exchange device for oxygen removal, since the heat-carrying capacity of water is much lower than that of steam, it is necessary to pump a large amount of water into the low-pressure heat exchange device for heat exchange and then serve as the heat source carrier of the deaerator, resulting in It is necessary to install a high-power water pump behind the water supply port of the deaerator, which consumes a lot of power for the plant

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