System for recovering exhaust steam waste heat of steam turbine to heat condensed water and use method

Abstract

The invention provides a system for recovering exhaust steam waste heat of a steam turbine to heat condensed water and a use method. The system comprises the steam turbine, a generator, a condenser, acompression fan, a steam exhaust heat exchanger, a condensation water pump and a first low-pressure heater. According to the system for recovering the exhaust steam waste heat of the steam turbine toheat the condensed water and the use method, exhaust steam (waste steam) of the steam turbine is continuously absorbed by the aid of a heat pump so as to reduce heat loads of the condenser and improve working capability of the steam turbine; meanwhile, the exhaust steam (waste steam) is heated, the enthalpy is increased, the exhaust steam is re-used as a heat source, so that partial exhaust steam(waste steam) which is to be abandoned originally is used sufficiently, and the power generation efficiency of a whole set is improved.

Description

technical field [0001] The invention belongs to the field of energy saving, and in particular relates to a system and a use method for recovering waste heat from exhaust steam of a steam turbine to heat condensed water. Background technique [0002] At present, the energy utilization efficiency of thermal power plants is low. This is because after the high-temperature and high-pressure steam generated by the boiler does work in the steam turbine, a large amount of exhaust steam (spent steam) from the steam turbine cannot be directly used due to low energy quality, and is directly discharged to the In the environment, the exhausted steam contains about 50% of the heat, which causes a huge waste of energy. [0003] Existing methods or devices for recovering waste heat from steam turbine exhaust usually use indirect means: 1. Renovate the low-pressure cylinder of the steam turbine to realize the high back pressure operation of the steam turbine for heat supply. This technology ...

AI Technical Summary

Problems solved by technology

This method has certain limitations and deficiencies: the waste heat cannot be used in non-heating seasons and all seasons in the south; the waste heat cannot be fully utilized in the heating period and the cold season, and the high back pressure operation of the unit causes the loss of the cold source to increase. The thermal efficiency is reduced; if it is applied to a wet-cooled unit, the steam turbine body needs to be modified, and the initial investment is large

2. The heat supply technology of absorption heat pump needs to be driven by some high-quality steam, and the exhaust heat of the steam turbine is extracted through the working medium. The disadvantage is that the initial investment of the unit is large, the COP is low, and the operation and maintenance are complicated. Generally, the working medium of the absorption heat pump is Lithium bromide, the application of this working fluid has potential safety hazards and other problems

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