Flue gas pretreatment system for reducing coal-fired flue gas CO2 gathering energy consumption

Abstract

The invention relates to a flue gas pretreatment system for reducing coal-fired flue gas CO2 gathering energy consumption, and belongs to the field of correlation techniques for coal-fired flue gas CO2 gathering. The flue gas pretreatment system for reducing coal-fired flue gas CO2 gathering energy consumption mainly comprises a direct contact type heat exchanger, wherein the direct contact type heat exchanger is arranged on a flue of a flue gas outlet of a desulfurizing tower; a spraying layer and a demister are arranged in the heat exchanger; the upper part of the heat exchanger communicates with a CO2 gathering device through the flue; a vacuum flashing device and a steam compressing device are arranged on the outer side of the heat exchanger; the bottom of the heat exchanger successively communicates with the vacuum flashing device, the steam compressing device and the CO2 gathering device through pipelines; the bottom of the vacuum flashing device communicates with the spraying layer of the heat exchanger through a pipeline, so that high-temperature water in the heat exchanger is changed into low-temperature water after flowing through the vacuum flashing device, and then is sprayed again from the inside of the heat exchanger. By the design of the brand-new structure, after the flue gas is desulfurized, the temperature of the flue gas can be reduced, the moisture content is reduced, and the effect of reusing waste heat is achieved.

Description

technical field [0001] The present invention relates to coal combustion flue gas CO 2 Capture-related technical fields, specifically, relate to a method for reducing CO in coal-fired flue gas 2 Flue gas pretreatment system that captures energy consumption. Background technique [0002] Currently, post-combustion CO in coal-fired power plants 2 Among the capture technologies, the alcohol amine solution absorption method is the most mature and has achieved large-scale industrial application. Pressure swing adsorption has also received widespread attention because of its low energy consumption and weak corrosion. The main adsorbent is zeolite 13X, which has a relatively high CO 2 Adsorption capacity and selectivity. [0003] Regardless of the alcohol amine solution absorption method or the zeolite 13X pressure swing adsorption method, the capture process has high requirements for the pretreatment of coal-fired flue gas. 2 The content generally needs to be reduced to 20mg / m...

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Problems solved by technology

[0004] However, after desulfurization, the temperature of the wet saturated flue gas is higher than 50°C, and there is about 12-16% water vapor, which requires a large amount of additional cooling capacity to pre-cool the flue gas, wasting a lot of energy, and the existence of a large amount of water vapor It will significantly reduce the absorption capacity of the absorbent, cause water imbalance in the capture system, and increase capture energy consumption

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