Heat recovery system with multi-stage deaerator

Abstract

The invention discloses a heat recovery system with a plurality of stages of hybrid heaters. Specifically, the heat recovery system comprises a BEST machine, five high-pressure heaters, five low-pressure heaters, the two to five hybrid heaters, boosting pumps and a condensate pump; each hybrid heater is configured with the corresponding boosting pump; the condensate pump is positioned between thelow-pressure heaters and a steam condenser; extraction steam of the first high-pressure heater is from a main steam turbine; the extraction steam of the second high-pressure heater to the fifth high-pressure heater is from the BEST machine; steam sources of the hybrid heaters are all from the BEST machine, wherein the steam source of the last stage hybrid heater is from the exhaust steam of the BEST machine; the extraction steam of the five low-pressure heaters is from the main steam turbine; and the last stage hybrid heater is connected with one of the low-pressure heaters, and the water supply of the last stage hybrid heater is from the low-pressure heater. According to the heat recovery system with the plurality of stages of deaerators, the circulating efficiency of the system is improved; the superheat degree of the steam is fully utilized; the project cost is reduced; the cold end loss of the steam is reduced; and the heat recovery system with the multiple stages of deaerators isparticularly suitable for the situation that the steam extracting steam of a plurality of heaters are close to the saturation pressure of the steam, and the feed water flow is large.

Description

Technical field [0001] The invention relates to the field of power generation, and more particularly to a regenerative system provided with a multi-stage deaerator. Background technique [0002] In modern power plants, a regenerative system is usually used to increase the average temperature of the endothermic cycle and the temperature of the feed water entering the boiler to improve the cycle efficiency of the thermal system. [0003] A typical regenerative system diagram of a secondary reheat unit in the prior art is as follows figure 1 with figure 2 Shown. The steam turbine in the system has 10 stages of extraction steam, which are respectively provided to 10 heaters, respectively, the first-stage extraction 30 is provided to the No. 1 high-pressure heater, and the second-stage extraction steam 31 is provided to the No. 2 high-pressure heater and the third-stage extraction. 32 is provided for No. 3 high heater 2, four-stage pumping 33 is provided for No. 4 high heater 3, five-...

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Problems solved by technology

[0011] With the continuous development of technology, the parameters of the double reheating unit are gradually increasing. The reheating system in the above-mentioned existing technology can no longer meet the requirements. The parameters of the main steam are gradually increasing, and the parameters of steam extraction at all stages of the steam turbine are also increasing accordingly. The design parameters of the high-pressure heater are also gradually increased, which greatly increases the initial investment of the heater equipment

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