New process for treatment of chlorine tail gas in the production process of trichloroisocyanuric acid

- Apr 22, 2019-

The continuous optimization of the chlorine tail gas treatment process in the production process of trichloroisocyanuric acid can effectively reduce the pollution degree of the tail gas to the environment and play an important role in promoting the sustainable development of the enterprise. Based on the analysis of the comprehensive background and research progress of isocyanuric acid production, the status quo and improvement measures of trichlorophthalic acid production were analyzed, and the principle and application of the new chlorine tail gas treatment process in the production process were discussed. The rationality of this process is expected to provide reference and reference for relevant personnel.

The method of treating waste gas wastewater is characterized in that it comprises the following steps:

(1) The waste liquid is acidified to remove dechlorination, and at the same time, cyanuric acid is prepared:

The waste liquid after centrifugal dehydration of trichloroisocyanuric acid was placed in a static mixer, the pH was adjusted to 1.5 with hydrochloric acid, and the mixture was uniformly mixed. Dechlorination is carried out by countercurrent purging of the packed column, and the mixed liquid is dechlorinated. It is added to the upper part of the column, and the waste liquid reacts with hydrochloric acid to form chlorine gas and cyanuric acid. The compressed air is blown out from the bottom of the blown dechlorination column, and the chlorine gas generated by the reaction is taken out from the top of the dechlorination tower into the chlorine reaction reaction tank, and the reaction liquid is filtered. , cyanuric acid filter cake resumes production, and the filtrate is collected;

(2) Neutralization of filtrate and lime slurry to prepare anhydrous calcium chloride:

The filtrate collected in the step (1) was introduced into the neutralization reactor, stirring was started, and a lime slurry having a mass fraction of 70% to 80% was added thereto to obtain a mixed liquid until the pH of the mixture was 6.5. And add the mixture. Pressure filtration. The filtrate is obtained, and the filtrate is concentrated to 35% calcium chloride at a low temperature without steam, and the calcined concentrate is obtained with anhydrous calcium chloride;

(3) Chlorine gas reacts with calcium cyanurate solution to form carbon dioxide gas, and carbon dioxide gas is absorbed by alkali solution to prepare baking soda:

Cyanuric acid, calcium carbonate and water were prepared as a calcium chlorate solution at a weight ratio of 1:1.16:15, and added to a chlorination reactor, and chlorine gas taken out from the top of the blown dechlorination column was introduced into the chlorination reaction. . reactor. The chlorine gas reacts with the calcium cyanurate solution to form carbon dioxide gas. The carbon dioxide gas is completely absorbed by the 40% sodium hydroxide solution in the spray absorption tower to form a baking soda slurry, which is then concentrated, crystallized, centrifugally dehydrated, and dried to obtain baking soda.