Steam exhaust waste heat recovery system based on unit wet cooling unit

Abstract

The invention discloses a steam exhaust waste heat recovery system based on a unit wet cooling unit. The system comprises a steam turbine unit, a steam condenser, a cooling tower, a circulating water pump, a water / water heat exchanger, a circulating water system, a heat pump and a heating network heater, wherein the circulating water system includes a heating network water pipeline, a bypass water pipeline and a mixed water pipeline; the bypass water pipeline is connected with bypass water and heating network return water; and the water / water heat exchanger is connected with steam condenser circulating water and cooling tower circulating water. The invention aims to propose the novel steam exhaust waste heat recovery system for the unit wet cooling unit, can organically combine a low vacuum technology with a heat pump technology, realizes deep utilization of steam exhaust waste heat of the steam turbine, and prominently improves the energy utilization efficiency of the steam turbine.

Description

technical field [0001] The invention belongs to the field of waste heat recovery in power plants, and in particular relates to a waste steam waste heat recovery system based on a unit wet cooling unit. Background technique [0002] In my country, coal-fired thermal power units account for more than 70% of the total installed capacity of power generation. Waste steam waste heat recovery technology can reduce or even avoid the loss of steam turbine cold source caused by pure condensing thermal power generation, and improve the energy utilization efficiency of steam turbines. Therefore, it has become an important energy saving technology. [0003] Among the existing exhaust heat recovery technologies of steam turbines, low-vacuum operation technology and heat pump technology have received widespread attention: low-vacuum operation technology requires a substantial increase in the back pressure of the unit, resulting in a serious decrease in the volume flow rate of the final stag...

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Problems solved by technology

[0003] Among the existing exhaust heat recovery technologies of steam turbines, low-vacuum operation technology and heat pump technology have received widespread attention: low-vacuum operation technology requires a substantial increase in the back pressure of the unit, resulting in a serious decrease in the volume flow rate of the final stage of the steam turbine, threatening the operation safety of the unit. It is even necessary to replace the final stage rotor under heating conditions, which brings inconvenience to the operation of the unit and is not easily accepted by the power plant; the essence of the heat pump technology is to use the working ability contained in the steam extraction to drive the reverse Carnot cycle to recover Low-temperature exhaust steam waste heat, although this technology can significantly improve the energy utilization rate of the system, the investment of heat pumps is high, the floor space is large, and the installation location is limited (in order to facilitate the extraction of waste heat, it must be placed near the circulating water pipe outside column A of the steam turbine room), Difficult for plant planning and retrofitting

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