Low-temperature economizer and drainage recovery coupling water supply system and method

Abstract

The invention discloses a low-temperature economizer and drain recovery coupling water supply system. The system comprises a main condensed water supply unit, a low-temperature economizer water return unit and a drain water recovery unit, wherein the main condensed water supply unit is used for heating condensed water through a first low-pressure heater, a second low-pressure heater, a third low-pressure heater and a fourth low-pressure heater in sequence and then inputting the heated condensed water into a deaerator; the low-temperature economizer water return unit comprises a first water return branch, a second water return branch and a third water return branch, and the low-temperature economizer water return unit is used for inputting low-temperature economizer return water into the main condensed water supply unit through the first water return branch, the second water return branch or the third water return branch; and the drain water recovery unit comprises a first recovery branch, a second recovery branch and a third recovery branch, and the drain water recovery unit is used for recovering heat supply network drain water to the main condensed water supply unit through the first recovery branch, the second recovery branch or the third recovery branch, therefore, low-energy-saving return water and the heat supply network drain water can be recycled to different positions of a unit condensation water pipeline according to different return water temperatures, and the safety and economical efficiency of a unit are improved.

Description

technical field [0001] The present application relates to the technical field of power plants, and more specifically, to a low-temperature economizer and a drainage coupling water supply system and method. Background technique [0002] The design temperature of the heat network drain is generally 40°C-90°C. In order to improve the economic efficiency of the power plant unit, some power plants recycle the heat network drain to the inlet of the deaerator, and add a low-temperature economizer. The design return temperature of the low-temperature economizer is 102 ℃, the low temperature economizer returns water to the No. 2 low gas outlet. [0003] With the enhancement of the operating flexibility of the unit and the increase of heating and extraction steam, the temperature of the return water at low load is higher during low-load operation, resulting in the situation of No. If the temperature is lower than the condensate temperature at the No. 3 low-load outlet, the safety and...

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Problems solved by technology

[0003] With the enhancement of the operating flexibility of the unit and the increase of heating and extraction steam, the temperature of the return water at low load is higher during low-load operation, resulting in the situation of No. If the temperature is lower than the condensate temperature at the No. 3 low-load outlet, the safety and economy of the unit will be reduced

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