Mixed ionic liquid solution special for absorbing SO2 gas and preparation method thereof

Abstract

The invention relates to mixed ionic liquid formula solution, which consists of an ionic liquid A, an ionic liquid B and a mixed solvent C, wherein the positive ion of the ionic liquid A is the N,N-dialkyl imidazole positive ion or the N,N,N,N-tetra alkyl quaternary amine positive ion, while the negative ion thereof is the monobasic carboxylic negative ion; the positive ion of the ionic liquid B is the protonated alkylamine positive ion, while the negative ion thereof is the monobasic or binary or ternary carboxylic negative ion; and the mixed solvent C is aqueous solution of water, polyethylene glycol, polyglycol ether, propylene carbonate or tetramethylene sulfone. The mixed ionic liquid formula solution of the invention is strong base-weak acid and weak base-weak acid mixed salt solution, has wide pH buffering capacity, and can greenly efficiently absorb the SO2 gas in a reversible cycle mode. The mixed ionic liquid formula solution of the invention is adopted as a SO2 absorbent so that the requirement for the equipment required by SO2 absorption is simple, the operation condition of absorbing and desorbing SO2 is mild, the desulfurization efficiency is high, and the problems of waste solution and wastewater discharge and the like do not exist. The invention also discloses a preparation method for the mixed ionic liquid formula solution.

Description

technical field [0001] The present invention relates to SO in flue gas 2 A mixed ionic liquid solution in the field of gas absorption and separation and a preparation method thereof. Background technique [0002] Sulfur dioxide is a harmful acid gas that has a great impact on human health and the ecological environment. my country is a country dominated by coal energy, and the exhaust gas emitted by coal combustion contains a lot of SO 2 . Air polluted by sulfur dioxide not only causes local or global climate anomalies, but also directly threatens human health and social security. Therefore, how to economically and effectively control SO in coal-burning oil process and industrial flue gas 2 It is a key issue urgently needed to be solved in the field of energy and environment in our country and even in the world. Commonly used waste flue gas desulfurization methods have problems such as large floor area, high investment and operation costs, and difficulties in selling by...

AI Technical Summary

Problems solved by technology

At present, ionic liquids have been used as SO 2 Related patent reports on gas absorbents: For example, the Chinese patent application No. 200510069406.6 uses alcohol amine carboxylate ionic liquid as SO 2 Gas absorbent, the cation is the cation of ethanolamine, diethanolamine, triethanolamine or diglycolamine protonated by hydrogen, and the anion is acetate or lactate, but the ionic liquid is still a physical absorbent. 1atm SO 2 Under bias voltage, only about 1 mol of SO can be absorbed per mole of ionic liquid 2 , the absorption is limited, and a small part of the ionic liquid will be irreversibly lost during regeneration, which is not conducive to the practical application of industrial processes

Chinese patent application No. 200510073345.0 uses amino acid mixed ionic liquid to absorb acid gas. The ionic liquid prepared by it has high cost, high viscosity, poor thermal stability and oxidation resistance, which is not conducive to SO 2 Absorption and mass transfer, limited practicality

The hybrid ionic liquid hydrate reported in the Chinese patent application number 200910233387.4 has both physical and chemical absorption mechanisms, and can efficiently and reversibly absorb SO 2 gas, but the hybrid ionic liquid also has disadvantages such as high preparation cost and high viscosity, which limit its practical engineering use

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