Method for separating and recovering chlorine and oxygen of hydrogen chloride oxidation gas mixture by use of PSA (Pressure Swing Adsorption) technology

Abstract

The invention relates to a method for separating and recovering chlorine and oxygen of a hydrogen chloride oxidation gas mixture by use of a PSA (Pressure Swing Adsorption) technology and belongs to the technical field of gas separation. The method aims at a gas mixture generated by catalytic oxidation of hydrogen chloride and comprises the following steps of: firstly absorbing unreacted hydrogen chloride with water, dehydrating through concentrated sulfuric acid, and introducing a residual gas mixture into a PSA device so as to be separated, wherein the PSA device comprises at least two absorbing tower units, adsorbents filled in the absorbing tower units are at least one of silica gel and active carbon, and the volume proportion of the active carbon is 0-50%; chlorine with the purity of more than 99.2% is obtained after adsorption, pressure equalizing, flushing and desorption steps are carried out on the gas mixture, adsorption tail gas is oxygen with the purity of more than 99.5%, and the recovery rates of chlorine and oxygen are more than 98.5%. The method for separating and recovering the chlorine and oxygen of the hydrogen chloride oxidation gas mixture by the PSA technology, disclosed by the invention, is especially suitable for separation recovery of the chlorine and oxygen of the hydrogen chloride oxidation gas mixture, and has the advantages of simple process, high recovery rates and purities of chlorine and oxygen, and excellent economical and environmental-friendly benefits.

Description

technical field [0001] The invention relates to a method for separating chlorine and oxygen in the chemical industry, in particular to a method for selectively separating and recovering chlorine and oxygen from hydrogen chloride oxidation mixed gas by using a pressure swing adsorption (PSA) method. Background technique [0002] With the development of my country's national economy, many chlorine-containing industries have become an important part of the national economy, and their development has driven a large demand for chlorine. In some areas, there has been a contradiction between strong demand for chlorine and insufficient supply; Part of the chlorine gas is obtained from the chlor-alkali industry. Simply relying on expanding the scale of the chlor-alkali industry will lead to a contradiction in the balance of chlor-alkali. With the launch of new projects and the continuous release of production capacity, while meeting the demand for chlorine, there is a large surplus of ...

AI Technical Summary

Problems solved by technology

[0005] Due to the low activity of conventional catalysts, short life, difficult reactor design, and high energy consumption for subsequent product gas purification, this technology has been restricting large-scale industrialization.

However, because the cooling temperature is limited technically and economically, the amount of chlorine gas is only a limited part, which depends on the concentration of chlorine gas in the feed gas. In order to obtain all pure chlorine gas from VPSA, the separated chlorine gas must pass through further purification steps

Therefore, the disadvantage of adding a condensation / cryogenic distillation step before VPSA is that the chlorine-containing feed stream must be compressed to a high chlorine condensation pressure (0.5-1 MPa) and must be cooled to the corresponding chlorine condensation temperature

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