Thermal power plant thermoelectric decoupling system

Abstract

A thermal power plant thermoelectric decoupling system comprises two steam turbines, two condensers or two air cooling islands corresponding to the two steam turbines, a dead steam extraction system and a dead steam recovery and heat supply system. Dead steam is extracted through the dead steam extraction system and conveyed to the dead steam recovery and heat supply system through a pipeline. Thedead steam recovery and heat supply system is connected with a heat supply pipe network and comprises a first dead steam condenser, a second dead steam condenser, a steam increase machine and a steamincrease machine condenser. Dead steam of the steam turbines is recovered for heat supply, the discharge steam amount during heat supply consumption is reduced, thus, main steam flow is reduced, thepower of a high-pressure cylinder and an intermediate-pressure cylinder is lowered, and large thermoelectric decoupling is achieved; cold end losses can be reduced, and energy conservation and emission reduction are achieved; the self-balancing function is achieved, the off-design condition performance is excellent, and the adaptability is high; the steam turbine loads are adjusted rapidly; and the complementarity with thermoelectric decoupling technologies of other types is good, and the combined operation effect is better.

Description

technical field [0001] The invention belongs to the field of thermal power plants, and in particular relates to a thermoelectric decoupling system of a thermal power plant. Background technique [0002] During the heating period in winter, urban central heating mainly relies on the combined heat and power units of thermal power plants, which not only supply heat but also generate electricity. The conventional heat supply mode of the thermal power plant, the heat supply heat mainly comes from the exhaust steam of the medium-pressure cylinder of the steam turbine, which is used to heat the circulating water of the heating network. The steam exhausted from the medium-pressure cylinder is the steam that has done work in the high-pressure cylinder and the medium-pressure cylinder of the steam turbine. If the mid-row steam is used for heating, this steam must do work in the high-pressure cylinder and the medium-pressure cylinder. That is, in order to realize and ensure heat supp...

AI Technical Summary

Problems solved by technology

First, the middle row (conventional) steam extraction heating technology, which is the foundation of "thermoelectric coupling", without the ability of "thermoelectric decoupling"

Second, the optical axis heating technology, on the surface, is equivalent to "getting rid of" the low-pressure cylinder of the steam turbine. However, for a power plant with a dual-unit configuration, only "one optical axis unit" can be used, and the other must maintain "steam extraction and supply". hot mode

In this way, the ability of "thermoelectric decoupling" is largely limited

Third, the double back pressure and double rotor heating technology of the water cooling unit is greatly affected by the return water temperature of the heating network

For the severe cold period, the return water temperature of the heating network is high, and this solution will have some fatal problems: 1. The increase of back pressure will lead to the decline of the steam extraction capacity of the middle exhaust. When the heat is most needed, the steam extraction of the middle exhaust will be reversed Insufficient supply, resulting in insufficient heat supply; 2. The utilization of exhaust steam is limited

Thus, the ability to "thermoelectrically decouple" is largely limited

Fifth, heat pump technology, exhaust steam utilization is limited

Therefore, water slightly higher than the saturation temperature must be used to cool the superheated steam, and this high-temperature water needs another cooling water system to cool down, forming a (steam-high-temperature water-low-temperature water) collar cooling system, which is difficult to install in the steam turbine room implementation layout

This system is equivalent to pure steam extraction, and there is a blowing loss in the low-pressure cylinder, without any energy-saving benefits, and it will also lead to an increase in the actual coal consumption

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