An adjustable boiler air preheating system and method for integrated heat recovery and waste heat utilization

Abstract

The invention belongs to the fields of thermal power generation and the like and particularly relates to an adjustable boiler air preheating system and method integrating heat regeneration and waste heat utilization. According to the adjustable boiler air preheating system and method, air preheating, waste heat utilization and regenerative heat cycling are made to be combined organically; heat-transmission cycling condensate water is divided into a large open cycle in which a bypass low-pressure heater extrudes a steam turbine to perform high-parameter steam extraction and a small closed cycle in which the low-pressure heater (or an added heat exchanger) is used for absorbing heat to increase low-parameter steam extraction; heat flow is divided according to the temperature level difference, heat source and cold source resources are dynamically and sufficiently used, optimal gradient utilization of heat energy in the power generation thermodynamic cycle is achieved, the energy use quality is improved, and energy losses are reduced. According to the adjustable boiler air preheating system and method, the operation mode of the system can be optimized and adjusted automatically according to the change of the operation condition so that gradient utilization of energy of different qualities can be achieved and energy losses can be reduced, and the thermodynamic cycle efficiency and the system economy are maximized.

Description

technical field [0001] The invention belongs to the field of thermal power generation, etc., and is particularly aimed at the technical fields of boiler air preheating, thermal system heat recovery cycle, boiler flue gas waste heat and steam turbine exhaust waste heat recovery and utilization, and specifically relates to a comprehensive heat recovery and waste heat utilization. Adjustment boiler air preheating system and method. Background technique [0002] The heat recovery cycle of thermal power generation can reduce the loss of cold source, reduce the average heat transfer temperature difference (reduce irreversibility and loss) to improve the efficiency of the thermodynamic cycle. Without affecting the boiler feed water temperature and the average heat transfer temperature difference between the extraction steam and the feed water, the greater the low parameter extraction steam, the greater the power generation and the smaller the cooling source loss. Usually limited...

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Problems solved by technology

At present, due to the complexity of the indirect air-cooled peak cooling system, the investment in equipment is large, and the vacuum degree is generally only increased by about 2-5KPa, which is not economical.

Although the peak cooling method using spray water can greatly reduce equipment investment, the cost of desalinated water is too high and the economy is poor.

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