SU880452A1 - Method of extracting sulphur dioxides from gas mixtures - Google Patents

Description

This invention relates to absorption absorption of sulfur dioxide from gas mixtures and can be used in gas utilization schemes in the chemical industry. A known method for separating a mixture of sulfurous anhydride and hydrogen chloride by contacting chlorine on activated carbon. The resulting sulfuryl chloride is condensed and removed. The uncondensed gases are treated with sulfuric acid to completely remove SOj. and SOiClji; The disadvantage of this method is the use of large quantities of chlorine and sulfuric acid and the formation of by-products. A known method for the recovery of sulfur dioxide from pelvic mixtures is the absorption of an SO mixture. and HCI or HF, HBg with water and processing the resulting mixture in an absorption and stripping column. The mixture is fed to the middle part of the column. In the lower part, stripping is performed at 70-85 ° C and stripping gas (air or nitrogen) is supplied. From above, the column is irrigated with water at 15–20 C. The volatile components released from cm s are absorbed in the upper part. Purified hydrohalic acid is withdrawn from the bottom of the column. The disadvantage of this method is the presence of stripping gas in the output sulfur dioxide and the high corrosivity of the medium due to the presence of water. Closest to the proposed method for separating sulfur dioxide from a mixture with HC1 to SOj by absorption with an aqueous solution of glyoxal. To release absorbed SOi, the absorber is heated to 65-75 ° C. The resulting mixture of sulfuric and hydrochloric acids in glyoxal is periodically removed and neutralized with Ez :. The disadvantages of this method are the need for the drying stage of the isolated 50 before reuse and the need to use titanium equipment due to the high corrosivity of the medium. The purpose of the invention is to simplify and cheapen the process by eliminating the drying stage of isolated SOi and using stainless steel equipment while reducing the corrosivity of the medium.

The goal is achieved by the fact that as an absorbent SOj. sulfur chlorides and sulfur solution in sulfur chlorides with a sulfur concentration of 0.5-12% are used.

An increase in the concentration of sulfur in chlorides is unacceptable, since it leads to the crystallization of the solution from the solution and clogging of the apparatus in the zone of low temperatures. The use of solutions., Which contained less than 0.5 wt.% Sulfur, is undesirable, since chlorine leakage is possible. As the sulfur contained in the solution is consumed, it is added to the absorbent to maintain the concentration at a constant level.

The use of sulfur chlorides as an absorbent makes it possible to sufficiently completely remove SOg (up to 98-99%) from gas mixtures of different composition,

containing, for example, carbon dioxide, hydrogen chloride, chlorine, etc.

In the middle part of the absorption and stripping column with four theoretical plates in the absorption part and part - in the Stripping and Top Temperatures - 20®С, at the bottom - + 20®С, the gas mixture containing sulfuric anhydride is fed. Top column irrigate absorbent. Its consumption is b mol / mol of the gas mixture. The absorber is withdrawn from the bottom of the column and sent to a stripping column, where SOi is stripped at 90-1, the regenerated absorbent is recycled into the cycle. The unit operates in continuous mode.

The table shows the composition of the gas and liquid phase after the corresponding stages.

Thus, the proposed method for separating sulfur dioxide from gas mixtures due to the absence of water reduces the requirements for the corrosion resistance of the equipment used and. does not require further drying of the released 50. The possibility of re-use of the absorbent provides its economy and allows you to create a waste-free process of separation of gases.

Claims (3)

1. A method of extracting sulfur dioxide from gas mixtures by absorption 15 followed by separation from the absorbent by stripping, characterized in that, in order to simplify and reduce the cost of the process, sulfur chlorides or sulfur solution in sulfur chlorides are used as the absorbent. 2. The method according to item 1, about aphids and with the fact that the solution of sulfur in sulfur chlorides is used with a concentration of 0.5-12%, Sources of information taken into account in the examination 1. Patent No. 4698, cl. 12 i 17/25, 1953. 3. For the application of FRG 2542127, cl. B 01 J 1/00, 1975. 3. US patent No. 3492091, CL. 23-154, 1970 (prototype).