Air cooling unit steam turbine waste heat using system and method

Abstract

The invention relates to an air cooling unit steam turbine waste heat using system and method. The system is characterized in that a waste heat working medium in a steam turbine waste heat working medium pipe returns to the steam turbine side after entering a cold air pre-heater (2) to heat boiler cold air; the boiler cold air passes through an air heater to be subject to water condensation through a condensation water pipe (7), is heated again, and then enters an air pre-heater to push out boiler discharge smoke waste heat; and the part of waste heat enters a smoke-water heat exchanger along with smoke to be used for heating steam turbine low temperature condensation water, and a part of heated high temperature condensation water returns to a steam turbine side condensation water system through a condensation water pipe. As the steam turbine waste heat is used for heating the boiler cold air, the outlet smoke temperature of the air pre-heater is improved; and the smoke water heat passes through a smoke-water heat exchanger (5) to be absorbed by the low temperature condensation water, the low temperature condensation water becomes the high temperature condensation water to return to the steam turbine side so as to be used for pushing a high temperature section to carry out steam extraction and acting, and therefore the overall circulation heat efficiency of a unit is improved.

Description

technical field [0001] The invention relates to the technical field of thermal power generation, in particular to a system and method for utilizing waste heat of an air-cooling unit steam turbine. Background technique [0002] Most places in northern my country, especially the Three North regions, are relatively water-scarce areas. In the construction of thermal power units in places where the drought index exceeds the standard, air cooling is usually required to achieve the purpose of saving water. However, when the unit is air-cooled, the cooling effect is far worse than that of the wet cooling method, resulting in high back pressure of the steam turbine, which affects the power generation efficiency of the unit, and even cannot run at full load during peak load in summer, and is more sensitive to ambient temperature changes. [0003] Regardless of whether it is an air-cooled steam turbine or a wet-cooled steam turbine, based on the steam Rankine power cycle theory, the e...

AI Technical Summary

Problems solved by technology

Due to the current technical measures such as low-temperature economizer, due to the influence of low-temperature corrosion and other factors on the exhaust gas temperature, the energy grade of waste heat utilization is low, and the space for improving unit efficiency is limited.

[0005] In addition, in order to prevent low-temperature corrosion at the cold end of the space preheater in winter, steam extraction or auxiliary steam heating type heaters are usually used, the system is complex, and the energy consumption of the unit is increased due to the consumption of steam extraction

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