Deep flue gas waste heat recovery system based on absorption circulation

Abstract

The invention discloses a deep flue gas waste heat recovery system based on absorption circulation. The deep flue gas waste heat recovery system comprises a coal-fired flue gas system, a heat pump system and a heat network water system, wherein the coal-fired flue gas system comprises a boiler, a dust remover, a desulfurizing tower, an absorption tower and a chimney; and the heat pump system comprises an absorption heat pump and an open absorption heat pump. According to the deep flue gas waste heat recovery system, two times of heat exchange cooling are achieved through the desulfurizing tower and the absorption tower, flue gas waste heat is absorbed through the two-stage heat pump gradually, and gradient utilization of the flue gas waste heat is achieved; meanwhile, gradient temperature rising of heat network water is achieved, and thus, the whole energy efficiency of the system can be substantially improved; and the absorption heat pump is connected with the desulfurizing tower through an absorption liquid circulating pipeline, the open absorption heat pump and the absorption tower are connected through a concentrated solution regeneration circulating pipeline, equipment connectors are simple, existing equipment does not need to be transformed, and maintenance and replacement of the equipment are facilitated.

Description

technical field [0001] The invention belongs to the field of flue gas waste heat recovery, and in particular relates to a deep recovery system of flue gas waste heat based on absorption circulation. Background technique [0002] In the coal-fired boiler system, the exhaust heat loss accounts for more than half of the total heat loss of the boiler, resulting in huge energy waste. Deeply recovering the huge potential contained in flue gas and improving the energy utilization efficiency of boilers has become an important measure for energy conservation and emission reduction in my country. [0003] The flue gas contains a large amount of gas combustion products such as CO2, SO2 and NOX, and its acidity and dew point corrosiveness have a great impact on the waste heat recovery equipment, making it more difficult and costly to recover the waste heat from the flue gas. Furthermore, the temperature of the flue gas exhausted from the chimney is high, so that the low-grade waste hea...

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Problems solved by technology

[0003] The flue gas contains a large amount of gas combustion products such as CO2, SO2 and NOX, and its acidity and dew point corrosiveness have a great impact on the waste heat recovery equipment, making it more difficult and costly to recover the waste heat from the flue gas

Furthermore, the temperature of the flue gas discharged from the chimney is high, so that the low-grade waste heat contained in the flue gas is released into the air, further causing energy waste

[0004] In order to recover and reuse the waste heat of the flue gas, heat pumps are generally used to recover the waste heat of the flue gas. The heat exchanger exchanges heat with the flue gas, and then extracts the waste heat of the flue gas through the evaporator of the absorption heat pump, in which the flue gas directly exchanges heat with the low-temperature cooling water, and the heat exchange temperature difference is large, resulting in a large irreversible loss of heat exchange. The low-temperature flue gas also has sensible heat and latent heat, which has not been recycled, and the waste heat recovery rate of flue gas is low

Patent 201520893728.1 A comprehensive utilization system for waste heat of desulfurization tower in a thermal power plant, which uses the circulating fluid of the desulfurization tower to absorb the waste heat of the flue gas, and then uses an electric compression heat pump to recover the heat in the circulating fluid of the desulfurization tower. There is latent heat that cannot be absorbed, and the waste heat recovery rate of the flue gas is low. The flue gas is directly introduced into the circulating fluid of the desulfurization tower for heat exchange, which is easy to cause corrosion to the pipeline

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