Method and apparatus for capturing CO2 in flue gas by utilizing three-phase circulating fluidized bed and ammonia

Abstract

The invention relates to a method and an apparatus for capturing CO2 in flue gas by utilizing a three-phase circulating fluidized bed and ammonia, which adopt the ammonia as CO2 absorbent and the three-phase circulating fluidized bed as a reactor. By controlling the flow rates of flue gas and main water flow, gas and liquid in the three-phase circulating fluidized bed can flow in a continuous bubbling state, and chemically react to produce ammonium bicarbonate, and the flying ash in flue gas can promote the crystallization of the ammonium bicarbonate, so that the ammonium bicarbonate can be conveniently recycled; violent gas-liquid mass backmixing transfer is carried out in the three-phase circulating fluidized bed, so the three-phase circulating fluidized bed has high CO2-eliminating efficiency and processing capability; the processing equipment can simply operate, has low requirement on flue gas dedusting, cannot be easily blocked, can be conveniently maintained compared with a packed tower, and occupies a small area, and the investment cost is low.

Description

technical field [0001] The invention relates to CO in power plant flue gas 2 Treatment technology, especially a method for capturing CO in flue gas using circulating fluidized bed ammonia method 2 The method and apparatus, belong to CO 2 Treatment and discharge technology field. Background technique [0002] 75% of the world's CO 2 Emissions from fossil fuels, of which coal-fired power plants account for about 40.6% of the total emissions, so capture, store or utilize CO in power plant flue gas 2 approach is considered to mitigate CO in the near term 2 Emissions are more feasible. CO from existing power plant flue gas 2 The capture technologies mainly include absorption method, adsorption method, membrane method and cryogenic method. Since the flue gas of the power plant generally has a large flow rate and is at normal pressure, and the CO 2 The volume fraction of the flue gas is low, about 8% to 16% in the conventional flue gas. In addition, it also contains a large...

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Problems solved by technology

However, the packed tower has relatively high requirements for the packing, which requires better corrosion resistance and mechanical strength, and requires a larger porosity of the packing to avoid channel flow and uniform gas-liquid distribution, so the cost of the packed tower is relatively high

In the power station flue gas treatment system, due to the large amount of flue gas, the processing capacity of the tower is relatively large, so the tower diameter is large, the circulation rate is high, and the problem of uneven gas-liquid distribution caused by the amplification effect is serious.

Moreover, the packed tower will often be blocked, which makes cleaning and maintenance troublesome

Therefore, the use of packed tower ammonia method to capture CO in coal-fired power plants 2 technical solutions are subject to many limitations

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