Method and device for purifying hydrogen cyanide industrial waste gas by electrodialysis

Abstract

The invention discloses a method and a device for purifying hydrogen cyanide industrial waste gas by electrodialysis. The method comprises the steps as follows: filling the hydrogen cyanide waste gas into a cathode, and purifying the hydrogen cyanide waste gas by utilizing free radicals with strong oxidizing property generated by electro-fenton reaction at the cathode; purifying and concentrating part of cyanide ions which are not fully oxidized by utilizing the selective permeability of a cobalt-containing perfluoro-sulfonate ion exchange membrane at an anode; and adding hydrocyanic acid purified and concentrated at the anode with different types of salts to prepare cyanide which is low in toxicity and easy to store and transport. According to the method, the liquid phase adsorption capacity is increased, the harmful gas purifying capacity can be increased by utilizing the liquid phase adsorption, electrodialysis and ion exchange principles while higher gas purifying rate is obtained, the generated gas such as NH3, H2, O2 or the like can serve as a raw material for other industrial production, high-toxicity high-risk byproducts are prevented being generated in the purifying process, and byproducts with higher added values can be obtained by an enriching and depositing method.

Description

technical field [0001] The invention relates to a method and a device for purifying industrial waste gas with hydrogen cyanide by using electrodialysis technology, belonging to the field of environmental engineering. Background technique [0002] The molecular formula of hydrogen cyanide is HCN, and its molecular weight is 27.03. It is a colorless and transparent liquid, highly volatile, with a bitter almond smell, a flash point of 17.8°C, a boiling point of 25.7°C, a melting point of -13.4°C, and a relative density of 0.6884. Miscible with water, and soluble in ethanol, ether, glycerin, benzene, chloroform, etc. Many industrial waste gases contain more hydrogen cyanide, such as coke oven gas (containing HCN 0.5-1.5g / m 3 ), calcium carbide furnace gas (containing HCN 3-4g / m 3 ), yellow phosphorus tail gas (containing HCN 0.l-0.2 g / m 3 ), as well as the manufacture of acrylonitrile, acrylic resin, pesticides and insecticides, and other occasions that are engaged in the pr...

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Problems solved by technology

[0007] Publication No. CN 85108796 A discloses a process for removing hydrogen cyanide from a gas stream. The method is to remove HCN from a gas stream in two steps. First, the gas stream is contacted with a special oxidation reactant to remove large Partial HCN, then, the gas stream is contacted with polysulfide solution to reduce the hydrogen cyanide content in the gas stream, this method is not effective for the removal of low concentration of hydrogen oxide

[0008] The patent with application number 200810058504.3 discloses a method for purifying and recovering hydrogen cyanide in industrial waste gas by using a special hydrolysis catalyst. The method hydrolyzes hydrogen cyanide in waste gas into ammonia, and then determines the method of recovering ammonia according to the concentration of ammonia. It can also be cooled with ammonia water and enter the absorption tower to jointly remove hydrogen sulfide. The ammonia water after absorbing hydrogen sulfide can be regenerated with air in the regeneration tower to recover sulfur. This method uses special activated carbon impregnated with one or more copper and palladium salts. To make a hydrogen cyanide hydrolysis catalyst, this method needs to be heated to catalyze hydrolysis and then cooled to absorb, which consumes a lot of energy

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