Method for producing chlorine dioxide with high purity by adopting combined reducing agent

Abstract

The invention relates to a method for producing chlorine dioxide with high purity by adopting a combined reducing agent. The method comprises the following steps of: injecting concentrated sulfuric acid and a sodium chlorate solution into a generator to form a reacting mother solution; maintaining the reacting mother solution to a certain acidity, temperature and the content of sodium chlorate; then adding a combined reducing agent formed by mixing methanol, hydrogen peroxide, hydrochloric acid or sodium chlorate to react for generating chlorine dioxide gas and a byproduct namely acid mirabilite; cooling and then absorbing the chlorine dioxide gas by using low temperature frozen water to obtain a water solution of chlorine dioxide; and simultaneously recovering the byproduct. The conversion rate of the chlorine dioxide produced by the method is improved by 3-6 percent as comparison with that of the chlorine dioxide produced by a single reducing agent, the stability of chemical reaction is improved, the production cost is reduced, and the chlorine amount in the chlorine dioxide solution and tail gas exhausted from a chlorine dioxide absorbing tower is remarkably reduced.

Description

technical field [0001] The invention relates to a production method of chlorine dioxide, in particular to a method for producing chlorine dioxide by a sodium chlorate method. Background technique [0002] Chlorine dioxide is a strong oxidizing agent. Stable chlorine dioxide has been recognized by the World Health Organization as a good fungicide and disinfectant, and it is also a good paper bleaching agent. Industrial production began in the 1930s, and there are currently about 1,000 chlorine dioxide production plants in North America and Europe. At present, my country has realized the localization of small-scale chlorine dioxide production equipment for disinfection. However, for the large-scale chlorine dioxide preparation system for on-site preparation and on-site digestion, the country is still in the research and development stage. The large-scale chlorine dioxide used by existing paper companies The production system is imported complete set of equipment technology. ...

AI Technical Summary

Problems solved by technology

The sodium chlorate method mainly uses sulfur dioxide, sodium chloride or hydrochloric acid as the reducing agent, and the raw materials are widely obtained and the price is low. However, these methods have disadvantages such as low conversion rate and large proportion of chlorine gas.

The production of chlorine dioxide by hydrogen peroxide as a reducing agent is a newly developed method. Its process is efficient and the reaction speed is fast, but hydrogen peroxide is expensive, and hydrogen peroxide is a relatively unstable compound that is prone to decomposition and causes Unnecessary increase in cost

The methanol method is currently the leading production method, and its conversion rate is second only to the hydrogen peroxide method. However, the product contains a certain amount of chlorine gas. On the one hand, it increases the cost of bleaching wastewater treatment, and also causes the lack of chloride ions in the reaction system to cause unstable chemical reactions.

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