Waste heat recovery system and method with discharged smoke waste heat as heat source of air heater

Abstract

The invention discloses a waste heat recovery system and method with discharged smoke waste heat as a heat source of an air heater. According to the waste heat recovery system and method with the discharged smoke waste heat as the heat source of the air heater, a low-temperature economizer and the air heater are connected through a pipeline to form a first circulation loop, a circulating pump is arranged on an inlet pipeline of the low-temperature economizer, and an air heater intake water regulating valve is arranged on an inlet pipeline of the air heater; and the low-temperature economizer is connected with the circulating water side of a condensed water heater through a pipeline to form a second circulation loop, the condensed water side of the condensed water heater is connected with a low-pressure heater in parallel through a pipeline, and a booster pump is arranged on a condensed water connecting pipeline between the condensed water side of the condensed water heater and the low-pressure heater. The system and method have the advantages that the air heater is reserved, low-temperature corrosion of an air preheater is relieved, the low-temperature economizer recovers discharged smoke waste heat of a boiler, and power generation coal consumption of a steam turbine is reduced; and meanwhile, the defects that since the air heater consumes low-pressure suction steam of the steam turbine, the heat consumption of the steam turbine is increased, the temperature of discharged smoke is increased, and the heat efficiency of the boiler is reduced are overcome, and the problems that a low-temperature economizer pipeline system is high in cost and operating reliability requirement are solved.

Description

technical field [0001] The invention relates to a heater heating system, in particular to a waste heat recovery system and method using waste heat from exhaust smoke as a heat source of a power plant boiler heater, and belongs to the field of waste heat utilization in coal-fired power plants. Background technique [0002] In thermal power plants, among the various losses that affect boiler efficiency, the heat loss of boiler exhaust smoke accounts for the largest proportion. In general, for every 10°C increase in the exhaust gas temperature, the heat loss of the exhaust gas will increase by 0.5% to 0.8%, and the corresponding increase in coal consumption will be 1.2% to 2.4%. [0003] At present, the exhaust gas temperature of boilers in many coal-fired power plants in my country is generally higher than the design value, resulting in a decrease in unit power generation efficiency, a decrease in electrostatic precipitator efficiency, and an increase in coal consumption. In ...

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Problems solved by technology

The system retains the advantages of the heater to reduce the low-temperature corrosion of the air preheater, and the low-temperature economizer recovers the exhaust heat of the boiler and reduces the coal consumption of the turbine for power generation; The temperature rise reduces the disadvantage of boiler thermal efficiency, and it solves the problems of high cost and high operational reliability requirements of the low-temperature economizer piping system

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