A temperature-variable concentrated absorbent for capturing carbon dioxide and its application method

Abstract

The invention discloses a temperature-changing condensation absorbent for trapping carbon dioxide and an application method of the temperature-changing condensation absorbent. The absorbent comprises the following components in percentage by mass: 10%-80% of temperature-changing condensation amine, 5%-25% of a pH modifier, 0-10% of an assistant and the balance of water. The application method comprises the following steps: enabling an absorbent solution in an absorption tower to react with a gas containing carbon dioxide to form a primary pregnant solution; cooling the primary pregnant solution, collecting solids through a solid-liquid separator, and conveying the separated liquid back to a barren solution storage tank; heating the concentrated solid with a hot barren solution generated by a regeneration tower till the concentrated solid becomes a liquid, namely a secondary pregnant solution; conveying the secondary pregnant solution to the regeneration tower, carrying out pyrolysis to obtain carbon dioxide and regenerated primary barren solution; firstly, preheating the concentrated solid generated by the solid-liquid separator by the primary barren solution; and mixing with the liquid generated by the solid-liquid separator in the barren solution storage tank to form a secondary barren solution and trapping carbon dioxide in the absorption tower. The absorbent has the characteristics of low regeneration energy consumption and high absorption rate.

Description

technical field [0001] The invention relates to the technical field of gas absorption and separation engineering, in particular to a temperature-variable concentrated absorbent for capturing carbon dioxide and a use method thereof. Background technique [0002] At present, the chemical absorption method is generally used to capture carbon dioxide from large-scale carbon dioxide emission sources such as coal-fired power plants, refineries, and steel plants, especially from low-to-medium concentration emission sources. In the process, alkaline alcohol and amine substances are used as absorbents, which react with acid gas carbon dioxide in the absorption tower to form compounds, which are separated from the gas phase and leave the absorption tower with the rich liquid. The rich liquid is heated in the regeneration tower, and the compound formed by carbon dioxide and alcohol amine decomposes to release carbon dioxide and realize the regeneration of alcohol amine. This type of a...

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Problems solved by technology

[0004] The above measures also face many limitations in application: 1. Absorbents with low regeneration energy consumption have a low reaction speed due to their weak combination with carbon dioxide. They need to be used in conjunction with accelerators to promote the reaction. By weighing the regeneration energy 2. When the concentration of alcohol amines becomes high, foaming and mass transfer will be hindered in the absorption process due to changes in viscosity and surface tension. problems, and high-concentration alcohol amine solutions are more likely to degrade, causing the effective components to drop rapidly; 3. The new absorbents of non-alcohol amines are still in the exploration stage, and it is difficult to meet the actual needs in terms of raw material sources and prices; 4. Due to the difference in absorption and mass transfer characteristics of non-aqueous absorption solutions, the process design is more difficult, and the participation of non-aqueous solvent components increases the difficulty of solution purification and recovery, and increases the environmental protection risk

To sum up, the problem of high energy consumption in the current carbon dioxide capture process still needs to be solved

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