Diaphragm electrolysis method for preparing carbon monoxide and pypocholoride in micro-gap electrolytic tank

Abstract

The invention relates to a diaphragm electrolysis method for preparing carbon monoxide and pypocholoride in a micro-gap electrolytic tank, which comprises the following steps: fully reducing the inter-electrode distance of the electrolytic tank by adopting a snakelike gas-liquid circulation channel and a porous electrode; the electrolytic tank is divided into a cathode chamber, a middle chamber and an anode chamber by a bipolar membrane and a cation exchange membrane to form a three-compartment electrolytic tank; the cathode chamber is an organic composite electrolyte in which a large amount of carbon dioxide gas flows, the electrolyte in the middle chamber is a metal chloride aqueous solution, and the electrolyte in the anode chamber is also a metal chloride aqueous solution. In the electrolytic reaction process, carbon monoxide is generated on the cathode chamber, chlorine is generated on the anode, and hydroxide is continuously generated in the middle chamber; chlorine is separated through the gas-liquid separation tank and then guided into the middle chamber, the chlorine reacts with metal hydroxide generated in the middle chamber to generate pypocholoride, and the pypocholoride belongs to a main component of the 84 disinfectant. The method has the advantages of short process flow, simple operation method, low production cost, small occupied area of equipment, easiness in starting and stopping and the like.

Description

Background technique [0001] Carbon monoxide is the main component of chemical synthesis gas and an important raw material for the synthesis of a series of basic organic chemical products and intermediates; hypochlorite is an important disinfectant and bleaching agent, mainly used in bleaching, industrial wastewater treatment, papermaking, Textiles, pharmaceuticals, fine chemicals, sanitation and disinfection and many other fields. At present, the industry mainly uses coal and natural gas to synthesize carbon monoxide. This method uses natural resources coal, natural gas, etc. as raw materials to synthesize carbon monoxide through processes such as gasification and carbonylation, and then separate and purify carbon monoxide according to the purity requirements of production. , to obtain various contents of carbon monoxide; hypochlorite is mainly synthesized by calcium hydroxide and chlorine as raw materials in industry: 2Ca(OH) 2 +2Cl 2 =Ca(ClO) 2 +CaCl 2 +2H 2 O, the req...

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Problems solved by technology

This method has a history of more than 100 years of research, and it has not yet been applied industrially. The main problems are: first, carbon dioxide is a non-polar molecule, and its solubility in aqueous solution is very small, only 0.033mol / L in the standard state. The current density of the reaction is too low; second, when electrolyzing carbon dioxide to produce carbon monoxide in an aqueous solution, in order to improve the conductivity of the electrolyte, it is necessary to add an inorganic supporting electrolyte to the electrolyte, thus inevitably bringing some inorganic impurities into the electrolysis In the liquid, some of the impurities are electrodeposited on the surface of the cathode to form surface active sites with low hydrogen evolution overpotential, which leads to the acceleration of the hydrogen evolution reaction, and also reduces the electrocatalytic activity of the electrode material for the carbon dioxide electroreduction reaction; When electrolyzing carbon dioxide in aqueous solution to produce carbon monoxide, due to the specific electrode / electrolyte interface environment, a small amount of carbon dioxide undergoes deep reduction to form amorphous carbon, which adheres to the surface of the cathode, resulting in electrode poisoning [Y.Hori. Electrochimica Acta 50 (2005) 5354- 5369], the current efficiency of generating carbon monoxide is rapidly reduced to zero; the 4th, the reaction of carbon monoxide produced by electrolysis of carbon dioxide, its cathode reaction product is carbon monoxide, and the anode reaction product is oxygen, because carbon monoxide can be made by coal gas method, oxygen can be made by air separation method Therefore, the production cost of the latter two methods is very low, resulting in the high production cost of electrolyzing carbon dioxide to produce carbon monoxide, which is not economically feasible.

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