Gas Boiler Waste Heat Recovery and Purification System Based on Membrane Humidification

Abstract

The invention discloses a gas boiler waste heat recovery and purification system based on membrane humidification, which belongs to the technical field of flue gas waste heat recovery and purification. The system comprises a membrane type spray heat and mass transfer tower 7 and a flue gas recirculation device 2. The flue gas recirculation device 2 is respectively connected with a boiler 1 and themembrane type spray heat and mass transfer tower 7, after flue gas A passes through a fan 8, recirculation flue gas B is supplied to a draught fan, the recirculation flue gas B, and fuel gas I and high-temperature high-humidity combustion air H are introduced into the boiler 1 after mixed to supply gas J for the boiler so as to reduce NOx; the membrane type spray heat and mass transfer tower 7 isvertically divided into a liquid storage tank 11, a flue gas-medium circulating water heat transfer segment 3 and a flue gas-air heat and mass transfer segment 5 from bottom to top so as to be used for recycling the total heat of the flue gas. The system realizes the recycle of the total heat of flue gas waste heat, improves the heat efficiency of the boiler, and reduces the NOx emission of the boiler through the humidification of combustion air and the recirculation of the flue gas.

Description

Technical field [0001] The invention belongs to the technical field of flue gas waste heat recovery and purification, and in particular relates to a gas boiler waste heat recovery and purification system based on membrane humidification. Background technique [0002] Natural gas is one of the main energy sources for heating in Beijing, but the current gas boilers have two problems that need to be solved urgently: on the one hand, the flue gas condensation waste heat emitted by gas boilers is not fully utilized; on the other hand, the nitrogen oxides emitted by gas boiler flue gas It has not yet been well purified. If the waste heat utilization efficiency of gas-fired boilers and the flue gas purification effect are improved, it has important engineering application value to realize the energy saving of central heating and clean the air environment quality. At present, the following technical problems still exist in the use of natural gas as the main energy source for heating: [...

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Problems solved by technology

[0003] (1) The temperature of the flue gas discharged by the gas-fired hot water boiler is much higher than its dew point temperature, so that a large amount of latent heat of water vapor condensation is discharged with the high-temperature flue gas, resulting in a waste of heat

[0004] (2) The emission of nitrogen oxides from gas-fired boilers is high

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