Composite solvent for purifying acetylene and purification method thereof

Abstract

The invention relates to a composite solvent used for purifying acetylene in acetylene mixed gas prepared from hydrocarbon and a purification method of the composite solvent. High-purity acetylene and higher alkyne, which are obtained from the acetylene feed gas, can be used as chemical materials. The invention adopts the technical scheme that the components of the composite solvent are as follows in mass percentage: 70-85 percent of physical solvent, 10-20 percent of CO2-removing chemical assistant, 1-5 percent of polymerization inhibitor in an addictive, and 0.5-5 percent of corrosion inhibitor. A device used in the purification method consists of an absorption tower, three desorbers and accessory equipment; the feed gas is firstly in countercurrent contact with the composite solvent in the absorption tower, wherein the acetylene, the higher alkyne and CO2 are absorbed by the composite solvent, then the high-concentration acetylene is absorbed out in the first desorber, the residual acetylene is absorbed out in the second desorber, and the higher alkyne and the CO2 are absorbed out in the third desorber. The composite solvent is high in selectivity, excellent in stability and easy to regenerate; and the purification method is simple in flow and mild in operation conditions, and the acetylene product whose purity is higher than 99.5 percent can be obtained.

Description

technical field [0001] The invention relates to a composite solvent used for acetylene purification for obtaining high-purity acetylene from acetylene mixed gas produced from hydrocarbons and a purification method thereof, belonging to the field of chemical gas purification. Background technique [0002] In the acetylene raw material gas produced by hydrocarbon cracking, the acetylene content is only 8-15v%, and the rest are impurities. Impurities consist of H 2 、CH 4 , CO, CO 2、 N 2 Such light components (commonly known as non-condensable gases) and propadiene, methyl acetylene, butadiene, vinyl acetylene, diacetylene, C 6 + Equivalent components (often called higher alkynes). Impurities must be removed to obtain acetylene with a purity >99.5v%, in order to meet the raw material requirements of organic synthesis products. [0003] Acetylene purification methods include adsorption method and solvent method. The adsorption method uses the different adsorption capaci...

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Problems solved by technology

However, NMP solvent purification of acetylene also has the following disadvantages: ① need to desorb higher alkynes (0.018-0.023MPa, 90-128℃) under vacuum and high temperature; ② need water washing tower and vacuum evaporator to recover entrained solvent; Easily hydrolyzed in the tower to generate N-methyl-aminobutyric acid corrosion equipment

The patent DE2121571 uses a mixed solution of NMP:methanol:diethanolamine at a ratio of 84:15:1 to treat acetylene mixed gas to obtain high-purity acetylene, ethylene and CO 2 The total amount of impurities is less than 0.001v%, but the boiling point of methanol in the mixed solution is low (64.8°C), and the loss of solvent is large

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