Method and system for conducting three-level air preheating through waste heat of garbage power station

Abstract

The invention relates to an air preheating method for a garbage power station, in particular to a three-stage air preheating method by utilizing waste heat of the garbage power station, which comprises the following steps: primary air is heated by a first-stage heater, a second-stage heater and a third-stage heater in sequence and then is fed into a garbage incineration boiler for auxiliary combustion; wherein a heating heat source of the primary heater selects high-temperature circulating water from an outlet of a flue gas heat exchanger or high-temperature heat medium water from a hot water side outlet of an absorption heat pump according to different temperatures of circulating water at an outlet of a condenser; a heating heat source of the second-stage heater is from first-stage extraction steam a of a steam turbine; and a heating heat source of the third-stage heater is extracted steam of the steam pocket. According to the method, deep sustainable recycling of waste heat of the garbage power station is achieved, and the comprehensive efficiency of the generator set is improved; and meanwhile, drained water of the three-stage heater is conveyed to the garbage pit heat exchanger to further exchange heat with the garbage, so that sufficient fermentation and sufficient combustion of the garbage in the incineration boiler are promoted, and gradient utilization of energy is also realized.

Description

technical field [0001] The invention relates to an air preheating method for a garbage power station, in particular to a method and a system for performing three-stage air preheating by utilizing the waste heat of the garbage power station. Background technique [0002] The design of the waste heat boiler for waste incineration is 190℃~210℃. However, with the continuous improvement of living standards, the calorific value of domestic waste gradually increases. At the same time, due to the coking and ash accumulation in the boiler, the waste heat boiler outlet of some waste incineration power plants The exhaust gas temperature is even as high as 240℃~260℃, which leads to the reduction of the thermal efficiency of the whole plant and the waste of energy. [0003] In addition, when there are high temperatures in summer and autumn in some waste-to-energy plants, the temperature of the cooling water at the outlet of the condenser circulating water reaches about 35°C, or even clos...

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Problems solved by technology

On the one hand, although this method makes the primary air temperature reach the design air temperature and maintains the stable combustion of the waste incineration boiler, both low-temperature heating steam and high-temperature heating steam are high-grade energy steam, which are all used to heat the primary air. , it is easy to cause the loss of some high-grade energy of the unit, which will reduce the efficiency of the unit; on the other hand, the drain after the extraction and heat release of the boiler drum still has a relatively high temperature, generally in the state of wet steam, and is directly recycled to the deaerator. The deaerator cannot fully recover the hydrophobic amount in the circulation system, resulting in a waste of energy

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