Method for purifying coke oven gas of vacuum carbonate-process desulphurization and recovering sodium thiocyanate

Abstract

The invention relates to a method for purifying the coke oven gas of vacuum carbonate-process desulphurization and recovering sodium thiocyanate. The method comprises the following steps of cooling, cleaning tar, washing ammonia, removing benzene, removing oil, removing naphthalene and the like, and further comprises the step of recovering sodium cyanate from desulphurization and decyanation wastewater, and the step comprises the following specific steps: 1) adding active carbon; 2) filtering; 3) extracting and crystallizing; and 4) refining, and returning the mother liquor obtained by separation to an evaporator. According to the method disclosed by the invention, the treatment process is simplified, repeated recrystallization is avoided, and the treatment cost is greatly reduced, so that the recovered by-products achieve the requirements of industrial high-grade products, the energy consumption is greatly reduced, zero emission is really realized, and the requirement of green and cyclic economy is achieved.

Description

technical field [0001] The invention relates to the fields of coke oven gas purification and waste liquid utilization, in particular to a method for coke oven gas purification and recovery of sodium thiocyanate by vacuum carbonate method desulfurization. Background technique [0002] The vacuum carbonate coke oven gas desulfurization and decyanation process belongs to the wet absorption desulfurization process. The main process is to use carbonate solution to directly absorb hydrogen sulfide and hydrogen cyanide in the gas; the rich liquid that has absorbed the acid gas enters the regeneration tower for regeneration, and contacts with the rising water vapor at the bottom of the regeneration tower under vacuum and low temperature conditions. Acid gases are desorbed from the rich liquor; the resulting acid gases can be produced by the Claus process to produce elemental sulfur or by the contact process to produce sulfuric acid. In the process of desulfurization and decyanation...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide the coke oven gas purification of vacuum carbonate method desulfurization and the method for reclaiming sodium thiocyanate, to solve the poor trapping effect of the mist catcher behind the benzene washing tower in the prior art, which causes the washing in the coke oven gas Impurities such as oil, tar, and naphthalene enter the subsequent desulfurization system, causing frequent blockage of regeneration towers and vacuum pumps