Multi-effect cascade jet type heat exchange based exhaust steam waste heat recovering and heat and power jointly producing system

Abstract

The invention relates to a multi-effect cascade jet type heat exchange based exhaust steam waste heat recovering and heat and electrical jointly producing system, belonging to the field of exhaust steam waste heat recovering and heat and power joint producing. The system comprises a steam turbine, a multi-effect cascade jet heat pump, a heating network last-stage heater, a low-pressure steam-water heater, a high-temperature heating network heater, a steam condenser, a power generator and a condensate pump. The multi-effect cascade jet heat pump comprises a cascade first-stage mixing section, a cascade first-stage throat part, a cascade first-stage diffusing section, a cascade last-stage diffusing section, and a cascade last-stage distributor which are connected into a whole body in sequence, wherein the cascade first-stage mixing section is provided with a cascade first-stage jet opening. The system adopts the multi-effect cascade workflow, thereby the irreversible loss of the jet heat pump is greatly reduced, a large proportion of the exhaust steam is mixed with the medium-pressure extraction steam used as the driving steam, and the pressure is increased greatly. The primary heating network returns water, the technical problems of recovering the exhaust steam waste heat efficiently by adopting the jet heat pump and supplying heat by using the recovered exhaust steam waste heat are solved, and the waste heat recovering capacity is improved by several times.

Description

technical field [0001] The invention belongs to the field of heat and power cogeneration of exhaust steam waste heat recovery of steam turbines, and in particular relates to the design of a exhaust steam waste heat recovery heat and power cogeneration system based on multi-effect cascade jet heat exchange. Background technique [0002] At present, the main system forms of heating in northern China are: combined heat and power generation, regional boiler room and decentralized heating each account for about 1 / 3, among which the combined heat and power generation has the highest primary energy utilization efficiency, the best emission reduction effect, and the most economical efficiency The promotion and application are limited by factors such as the difficulty of large-scale expansion of the heating network scale and its heating capacity, and it is urgent to adopt better technical routes and policy planning for promotion. The relevant patented technology of waste steam heat r...

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Problems solved by technology

However, the actual problem at present is that the current traditional steam injectors are limited by the pressure ratio of the driving steam and the sucked steam, and often only have a large compression ratio and expansion ratio within a certain range. Injection ratio, and its injection ratio is usually around 0.2 to 0.8. If it deviates from its reasonable compression ratio and expan

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