SU941281A1 - Process for producing sulphur from gases - Google Patents

Description

(54) METHOD FOR PRODUCING SULFUR FROM GASES

one

The invention relates to methods for producing sulfur from gases containing SO2, and can be used to purify gases and utilize sulfur in the oil and gas, metallurgical, chemical, and other industries.

A method for producing sulfur from sulfur dioxide with a low concentration of SOa (0.3-2.0%) is known by absorbing it with an aqueous solution of an alkali metal or ammonium salt, followed by reducing the saturated H2S absorbent and liberating sulfur by settling, flotation, heating the reduced sorbent in autoclaves evaporation followed by sulfur condensation 1.

There is also known a method for producing sulfur from weakly concentrated sulfur gases by absorbing SO2 with an aqueous solution of ammonium sulfide to obtain a solution of ammonium bisulfite and reducing the latter with hydrogen sulfide. The sulfur formed is released by heating the recovered solution in autoclaves 2.

The disadvantages of these methods are the difficulties that arise when organizing the interaction of relatively small amounts of reducing gas (hydrogen sulfide) with a relatively large amount of saturated hydrating solution at the stage of its reduction. The reduction operation is carried out by sparging metered amounts of hydrogen sulfide gas through a layer of saturated solution. This requires a long time (up to 20 minutes) to carry out the recovery operation and large ems of bubbling apparatus. However, since the contact time for the reduction operation is limited by the time of gas bubbles rising, a part of the reducing gas does not have time to react and this reduces the use of the reducing gas, which ultimately reduces the degree of purification of the source gas and the yield of the target product - elemental sulfur.

The purpose of the invention is to increase the yield of the target product.

The goal is achieved by the fact that

Claims (2)

20 according to the method for producing sulfur from sulfuric anhydride containing gases by absorbing it with an aqueous absorption solution and then recovering the absorbed sulfur dioxide by contacting with hydrogen sulfide gas and separating the sulfur formed with sulfuric acid, the absorption solution is divided into two streams, one the amount of 30-60 wt. ° / o is subjected to contacting with the entire amount of hydrogen sulphide. the retaining gas necessary to reduce all sulfur dioxide contained in two parts x t the absorption solution, after which the recovered part of the absorption solution with smeschivayut unreduced portion. The process is as follows. Sulfur dioxide containing sulfur dioxide is washed in a scrubber with an aqueous solution of an average salt of sulfurous acid and an alkali metal or ammonium or an aqueous solution of any other absorbing material. Sorption of sulfur dioxide proceeds through the reaction SOj-t-SOz-t-HjO 2HSO5 The saturated absorption solution flowing out of the scrubber is divided into two parts. Part of the solution in the amount of 30-60 vesr / o is contacted with hydrogen sulfide or gas containing hydrogen sulfide in a tubular coil-type reactor. For one mole of sulfur dioxide adsorbed in a scrubber, 2 mol of hydrogen sulfide or with some excess is fed. The reduction in the tubular reactor proceeds via the reaction 2HSO3 + 2H2S 3S-t-SC4 3H20 The reduction process uses the ability of aqueous absorption solutions, saturated with sulfur dioxide, after their reduction with hydrogen sulfide to form sulfur and sulfite to absorb additional amounts of hydrogen sulfide to form thiosulfate SO5 + H2S Next, the recovered portion of the saturated absorption solution is shifted into the circulating tank with the remaining unrestored portion of the saturated absorption solution, into the rez Tate thereby forming elemental sulfur and sulfite 2HSO ;, + 2S2tfj- 4H 3S-b3SOf ZNgO. With the formation of sulfite in the solution, the absorption capacity of the solution is restored. The recovery rate is high and the process can be carried out directly in the circulation tank of the absorption scrubber, it does not require any special hardware, as it is done in a known method. X. The sulfur formed is separated by fcation or sedimentation, by heating the consolidated solution in autoclaves or by evaporating the reduced solution with pi followed by sulfur condensation. Example 1. Waste sulfur dioxide containing about 1% sulfur dioxide is washed in a packed absorption column with a diameter of 180 mm and a height of 2500 m, filled with Raschiga porcelain rings of 15x15 mm with a total height of the packing nozzle. in a 1500mm column, with an aqueous solution of ammonium sulfite with a concentration of 0.2 mol per liter, having a temperature of 55-60 ° C, which is fed to the column for irrigation using a centrifugal pump from a 50-liter circulation tank. 70% of the absorber of the solution flowing from the column is fed by means of a centrifugal pump to an injection device, where it is biased with hydrogen sulfide gas, after which the gas-fluid that forms with the gas interacts in a tubular coil-type factor with a diameter of 4 mm and 20 m long. Next, the hydrogen sulfide-recovered solution is displaced with the remaining portion of the circulating absorption solution draining from the column and fed into the circulating tank, where the reactions are completed with the formation of elemental sulfur. The sulfur formed is separated by flotation. Examples 2-6. The process was carried out in the same way as in example 1, only the amount of solution sent from the absorption column to the reduction to the tubular reactor was 60, 50, 40, 30 and 25 weight / o, respectively. The results of the experiments are shown in the table. As can be seen from the table, the optimal values of the degree of utilization of the reducing agent and the yield of sulfur correspond to the amount of solution fed to the reduction, within the range of 30-60%. The proposed method makes it possible to increase the overall degree of sulfur recovery from the gas; by 2.3 ° / o, and in addition, it shortens the time of regeneration of the saturated absorption solution. Claims method for producing sulfur from gases containing sulfurous anhydride by absorption with an aqueous absorption solution followed by recovery of absorbed sulfur dioxide by contacting with hydrogen sulfide-containing gas and separating sulfur formed in this process, characterized in that, in order to increase the yield of the target product, saturated sulfur dioxide the absorption solution is divided into two streams, one of which, in the amount of 30- 60 wt. ° / o, is contacted with the whole amount of hydrogen sulfide-containing gas, necessary for the recovery of all of the sulfur dioxide contained in the two parts of the absorption solution, after which the absorbed part is absorbed. Of this solution is mixed with the unrestored part. Sources of information taken into account in the examination. Vilesov, NG, et al. Sulfur recovery from WASTE gas using liquid-phase methods. M., TsNIITsvetmet Economics and Information 1979. Vol. 8, s. 68 2. French patent He 2254360, cl. From 01 to 17/04, 1978.