CS275686B6 - Process for obtaining polysulfide lye - Google Patents

Abstract

The solution relates to obtaining polysulfide liquor during gas desulfurization during pressure coal gasification. The gas is subjected to the action of an oxidation-reduction solution and the resulting sulfur is subjected to a reaction with alkali metal hydroxide and/or their mixture, with a concentration of 1 to 45% by weight, at a temperature of 30 to 160 °C and a pressure of 0.01 to 1.9 MPa. Polysulfide liquors are used in the paper industry.

Description

The present invention relates to a process for obtaining a polysulfide liquor by treating sulfur from the redox removal of sulfane from pressurized coal gasification gases.

Previously known and used methods for preparing polysulfide lyes in the paper industry consist in practically dissolving elemental or sublimed sulfur directly in boilers or recovery boilers in pure aqueous sodium hydroxide solution · and / or in operating liquors in various machinery equipped with dissolving reactors equipped with heating systems and pumping stations. technique for recirculation of solvent lye and sulfur charge. Typically, the systems described operate at reaction temperatures of about 170 DEG C. and pressures of up to 1 MPa, the reaction time ranging from 25 minutes, depending on the type of sulfur to be treated and the technology chosen. up to 50 min. .

Other known methods of processing production elemental sulfur from oxidation-reduction desulfurization processes are mainly based on remelting concentrated sulfur sludge in melting apparatuses into molten elemental sulfur and sulfur slag. Another way is to process it into sulfuric acid. .

These methods are particularly disadvantageous in that up to 12% of all sulfur is lost as sulfur slag, which is still unprocessable, and in that the molten sulfur always contains an increased content of undesired components of inorganic or organic character, which prevents its further processing. Another disadvantage is that the melters used so far have a high failure rate, especially in their measuring and control part, and thus significantly reduce the efficiency and reliability of operation. Another disadvantage is that these systems operate at temperatures up to 170 ° C and pressures from 1 MPa and are characterized by high consumption of heating medium.

The process for obtaining a polysulfide liquor by sulfur treatment: His pod- •. The state is that a gas containing sulfane in an amount of 0.1 to 30 g / πΡ is subjected to a soil; of an oxidation-reduction solution containing an organometallic iron compound to form! sulfur which is reacted with an aqueous alkali hydroxide solution, preferably hydroxy; du solution having a concentration of from 1 to 45 wt% _of t., and the pressure to 1.9 MPa. According to another feature, you; In the present invention, a complex of iron with methylenediaminotetraacetic acid was used as the organometallic iron compound.

The basic effect of the process for obtaining polysulfide lye is to use a high ·; reactive forms of elemental sulfur directly from the desulphurisation process without its drying or melting. According to the process of the invention, the sulfur treatment is also advantageous in that the reaction time of the sulfur and the alkali metal hydroxide solution and / or a mixture thereof is shortened in this process compared to the polysulfide lye production methods used hitherto, the molar ratio being 2 - 2 -. 5 + 3 / S ₂ 0j increases, hence the yield of active ingredients of the polysulfide liquor | rising. Furthermore, the process according to the invention allows the direct use of certain components of the washing liquid oxidation-reduction desulfurization methods as catalysts accelerating the formation and yield of S 2 and S 2 in polysulfide liquors. In addition, this method of sulfur treatment makes it possible to substantially reduce the energy consumption during its processing.

The process according to the invention is further characterized in the following working examples.

.v | Example 1 is 21 g of dry sulfur obtained from the desulfurization process of pressure gas expansion gases

With brown coal, the paroxygen mixture was heated with 110 ml of a 45% strength by weight NaOH solution using an aqueous solution of iron complexed with ethylenediaminetetraacetic acid. temperature of 80 to 100 ° C for 10 minutes. After completion of the reaction, the sample was transferred to a 1 liter flask and made up to the mark. The resulting reaction mixture contained 5.8 grams of sodium sulfide and 5 _{g of} 9 grams of sodium polysulfide.

CS 275 686 B6

Example 2

36.2 g of a sulfur paste containing 42% by weight of water with the residues of the washing desulfurization solution remaining in the sulfur paste after decantation were mixed with 110 ml of 45% by weight of an aqueous NaOh solution heated to 60-80 ° C for 10 minutes. After completion of the reaction, the reaction product was transferred to a 1 liter flask and made up to the 1 liter mark. The resulting reaction mixture contained 5.1 grams of sodium monosulfide and 7.2 grams of sodium polysulfide.

Claims (2)

PATENT CLAIMS A process for obtaining a polysulphide liquor by treating sulfur with redox desulphurisation of pressurized coal gasification gases, characterized in that the gas containing sulphane in an amount of from 0.1 to 30 g / m ^{3 is} treated with an redox solution to produce sulfur, which is reacted with an alkali metal hydroxide and / or a mixture thereof, preferably with sodium hydroxide, at a concentration of from 1 to 45% by weight, at a temperature of from 30 to 160 ° C, a pressure of from 0.01 to 1.9 MPa. 2. The process according to claim 1, characterized in that a complex of iron with ethylenediaminetetraacetic acid is used as the organometallic iron compound ensuring sulfane capture.