Middle-low temperature regenerated carbon dioxide capturing absorbent and application method thereof

Abstract

A middle-low temperature regenerated carbon dioxide capturing absorbent is composed of the following components in percentage by weight: 10 to 80% of low temperature regenerated amine, 5 to 25% of pH adjuster, 0 to 10% of auxiliary agent, and the balance being water. When the absorbent is used, low temperature regenerated carbon dioxide absorbent in an absorbing tower reacts with gas containing carbon dioxide to form a rich liquor, the absorbing temperature is 30 to 50 DEG C, and the absorbing tower pressure is 0.05 to 6 MPa. The rich liquor is preheated in a barren liquor / rich liquor heat exchanger to flash-evaporate part of carbon dioxide gas, after flash evaporation the rich liquor is transferred to a regeneration tower to carry out low temperature pyrolysis, the rich liquor is converted into barren liquor, at the same time carbon dioxide is generated; the temperature of the bottom of the regeneration tower is 70 to 100 DEG C, the generated hot barren liquor in the regeneration tower is conveyed to the absorbing tower for capturing carbon dioxide after going through the heat exchanger, and thus the whole absorption-regeneration-absorption circle is completed. The provided absorbent can be regenerated at a low temperature, and thus the capturing cost can be reduced in multiple aspects.

Description

technical field [0001] The invention relates to the technical field of gas absorption and separation engineering, in particular to a medium-low temperature regenerated carbon dioxide capture absorbent and a use method thereof. Background technique [0002] At present, in industrial large-scale carbon dioxide emission sources, especially in low-concentration emission sources, the chemical absorption method is generally used to capture carbon dioxide. The absorbent is represented by ethanolamine. It is separated into the rich liquid and leaves the absorption tower. The rich liquid is heated in the regeneration tower, and the compound formed by carbon dioxide and alcohol amine is decomposed by heat to release carbon dioxide and realize the regeneration of alcohol amine. The main problem of this type of absorbent is the high energy consumption of the capture, the regeneration temperature is 110-120°C, and a large amount of saturated steam is required, which is also one of the m...

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Problems solved by technology

However, if the absorption capacity of the absorbent for carbon dioxide is not strong or the reaction speed is low, it will be difficult to achieve the capture rate of the absorption tower, and the load of carbon dioxide in the rich liquid will not meet expectations, which may also affect the efficiency of the capture process. Therefore, there are few feasible discoveries of carbon dioxide absorbers regenerated at medium and low temperatures.

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