CO2 trapping absorbent with secondary phase change function and application method

Abstract

The invention provides an absorbent with a secondary phase change separation function for capturing carbon dioxide (CO2) in wet gas and an application method. The CO2 absorbent is prepared from the following components in percentage by mass: 20 to 70 percent of organic alcohol amine, 20 to 70 percent of bivariant driving agent and the balance of auxiliary agent. The application method of the absorbent comprises an absorption tower, a first phase change separator, a desorption tower, a second phase change separator and a moisture control unit, the absorbent generates liquid-liquid phase change after absorbing CO2, when a heavy phase is desorbed, a tower top vapor phase is condensed and then generates liquid-liquid phase change again, and water balance of a system is adjusted through the moisture control unit. According to the CO2 trapping absorbent and the application method thereof, a secondary phase change separation and enrichment process can be generated, the amount of a desorption solution is reduced, regeneration energy consumption is reduced, meanwhile, the key problem of water balance regulation and control in a trapping system is solved, and long-term stability of absorbent composition and trapping performance is guaranteed.

Description

technical field [0001] The invention belongs to the technical field of gas separation, and in particular relates to a CO trap with secondary phase transition function 2 Absorbents and methods of application. Background technique [0002] In recent years, CO emissions due to fossil fuel consumption 2 Greenhouse gases are one of the main contributors to global climate change, requiring large-scale reductions in CO 2 has become the consensus of mankind. Energy and industrial sectors such as coal-fired power plants, steel plants, and cement plants are large sources of fixed CO 2 Emission sources, the flue gas or tail gas of these emissions generally contain a certain concentration of CO 2 , N 2 、H 2 O et al., How to efficiently and cost-effectively capture or separate CO from these wet gas mixtures 2 appears to be particularly important. At present, carbon capture and storage technology is a feasible way to effectively reduce global carbon dioxide emissions, which can re...

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Problems solved by technology

However, after the phase transition of these water-soluble absorbents, CO 2 When the enriched phase is regenerated, the vapor phase at the top of the tower is condensed by the condenser and becomes a homogeneous aqueous solution, which contains some organic amines or water-soluble organic compounds. These systems have no water separation function, and the solution needs to be returned to the system. Long-term operation causes the absorbent in the system to Changes in concentration make it difficult to resolve the water balance of the system

Therefore, when the existing absorbent capture system treats wet flue gas, direct discharge of condensate will cause absorbent loss and environmental hazards, and it is impossible to directly discharge excess water in the system. If additional separation technology is added to further process the absorbent components aqueous solution, will lead to an increase in the total cost of capture

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