Ionic liquid for phase change absorption of sulfur dioxide

Abstract

The invention discloses ionic liquid for phase change absorption of sulfur dioxide. The ionic liquid consists of organic cations and organic or inorganic anions. The cations are provided by heterocyclic compounds such as imidazole and piperazine, and an amine compound; the anions are provided by carboxylic acid, amino acid, inorganic acid and the like. The substances that provide the cations and the anions are added according to the stoichiometric ratio of reaction, and between 20 DEG C and 50 DEG C, the ionic liquid can be prepared after the complete reaction of the substances. The ionic liquid has the advantages of low volatility and good thermal stability; the key point is that a liquid-solid phase change occurs after SO2 absorption, and only one phase enriched with SO2 is sent to a regeneration tower for desorption, so that the desorption energy consumption is reduced to a great extent. Moreover, the SO2 can also be cyclically absorbed. Therefore, the ionic liquid is an absorbent with good performance, has a great application prospect and is suitable for the collection and the separation of the SO2 in coal-fired flue gas.

Description

technical field [0001] The invention relates to SO in coal-fired flue gas 2 Capture, separation, and recovery technologies, specifically related to phase change absorption of SO 2 The ionic liquid belongs to the field of energy saving, emission reduction and gas purification. Background technique [0002] SO 2 It is a colorless gas with a strong pungent smell. It will cause serious harm to human health, plants and the ecological environment. It is one of the main air pollutants that are currently deteriorating air quality. Man-made SO 2 The main sources of pollution can be summarized as: fuel combustion, industrial production processes, transportation. In our country, the proportions of these three sources are 70%, 20% and 10% respectively. A large amount of SO produced by fuel combustion 2 will cause great harm to public health, therefore, effective control of SO 2 It is an important research direction in the field of energy utilization and environmental protection i...

AI Technical Summary

Problems solved by technology

Relatively speaking, the organic amine method has high desulfurization efficiency and high selectivity (of which SO 2 is CO 2 50,000 times of that), the system has little corrosion, and the by-product has a high concentration of SO 2 The gas can be used to produce sulfuric acid, and the absorbent has good stability and low foaming, etc.; however, the organic amine desulfurization method has the disadvantages of high desorption temperature, large consumption of amine regeneration steam, and high energy cost

Another ionic liquid flue gas desulfurization technology, because it has the advantages of environmental protection, regeneration, and adjustable structure, many researchers have synthesized a series of guanidinium salts, imidazoles, alcohol amines, and quaternary amines. Use it to absorb SO 2 , explore its absorption performance and mechanism, and according to the designable characteristics of its structure, introduce various functional groups on the anion and cation in the ionic liquid: ether group, cyano group, halogen, etc., functionalize it, and continuously synthesize ions with specific needs liquid to improve SO 2 absorption properties; but ionic liquids absorb SO 2 The bonding force is relatively strong, the desorption conditions are harsh, the desorption energy consumption is large, and regeneration and recycling are difficult