SU744191A1 - Method of burning sewage containing sulfur and sodium compounds - Google Patents

Description

Treatment of waste effluent gases in the presence of sodium alkali and the production of sodium sulfate, and its reduction to sodium sulfide, and 3.

A significant disadvantage of this method is the consumption of additional fuel for the production of sodium sulfide sulphate, which forms oxidation and neutralization of gaseous products}.

The purpose of the invention is (the increase in economics: a m nical efficiency of the process.

This is achieved by the fact that a process involving the thermal treatment of sprayed wastewater of the product. Incomplete combustion of fuel, the extraction of existing and the resulting sulphide of the sludge, the proportion of sulfur-containing products of thermal treatment of wastewater in the presence of sodium alkali to produce sodium sulfate it is in sodium sulfide, heat-treated products, and wastewater is directed to the reduction of sodium sulfate to sulfide before it is burned.

In the drawing, the technological scheme is given in principle.

The diagram shows the stage ./ of thermal treatment of wastewater with products of incomplete accumulated drilling, stage 2 of the reduction of sulfate to sulfide, stage 3 of oxidation of the products of thermal treatment of wastewater, and stage 4 of obtaining sodium sulfate by a known method.

The original wastewater passes through stage 1 heat treatment. The reducing atmosphere at this stage is created by burning fuel with: air consumption coefficient a 0.55–0.95, Burning the fuel with a lower one. fuel consumption ratio is not possible, a higher air consumption coefficient leads to the creation of an oxidizing atmosphere. Here, evaporation of water and overheating of its vapor, thermal decomposition of organic substances with the formation of gaseous prod gates — CO, Iz, SpZZ, COS, etc., thermal decomposition of unstable sulfur and sodium compounds occurs, resulting in the formation of sodium sulfides. Polysulfides dissociate with sulfur and form sulfide, gndrosulfide is converted to sulfide and hydrogen sulfide, thiosulfate decomposes into sulfate, sulfide and hydrogen sulfide, sulfite decomposes into sulfate and sulfide.

In addition, some of the sulphide formed undergoes carbonization to form sodium carbonate and hydrogen sulfide. In this way, a melt of sodium mineral compounds, consisting of 90% of sulphide, and gaseous products of heat treatment of waste water containing CO, HZ, HsS, COS, 82 and other incomplete products are formed. The starting temperature of their gases is 1250 ° C, which ensures the yield of mineral products in the form of a melt.

The gaseous effluent from the heat treatment of the waste water is directed to the recovery herd 2, where it reacts with sodium sulphate obtained in a known manner from sulfur dioxide after the oxidation stage 3. The resulting sulphide sodium reactant is withdrawn as a melt. The free and bound sulfur in the gaseous products of the thermal treatment of the wastewater passes through stage 2 of reduction without change. Thus, all sulfur, bound to organic and mineral impurities of waste water, transforms into the form of sulfide, which is a valuable commodity product.

Oxygen released during the reduction of zlfate oxidizes a part of the product of incomplete combustion, therefore by the end of stage 2 of the reduction, the flue gases pass with a reduced content of incomplete combustion but sufficient to maintain the reducing atmosphere at any point on Sulfate paths in Stage II 2 restored.

Next, the gaseous heat treatment of wastewater is directed to the stage 3 o.acidification. Here CO, H2, COS. H2S and S2 are oxidized by air oxygen to C02, H20 and S02. In stage 4 of the preparation of sodium sulfate, S02 is converted to sulfate by a known method, for example, by introducing a solution of soda in a high temperature. Full oxidation products crawled in stage 3 of oxidation. The sodium sulfate from step 4 of the sodium sulfate phase is sent to the reduction step 2, where it is reduced to sodium sulfide by reducing components present in the heat treatment products of the waste water.

The implementation of the method allows the stage of converting sodium slfate to sflide sodium from the energy and material flows of the actual disposal process without using extraneous means within a single technological system, revealing and using the new property of waste heat treatment products - their ability to be A. An active reducing agent in the process of converting sodium sulfate to sulfide.

The proposed method allows one to save more than 26% of the fuel in comparison with the known methods and to obtain the same amount of commercial product. one

Claims (3)

1.Shurygni, A.P., Bernadiner, M.N. Fiery neutralization of industrial waste water, Kiev, “Technique, 1976. 2. USSR author's certificate number 385930,; cl. C 02 C 5/04, 1973. 3. Certificate of authorship on application no. 2305388/26 cl. C 02 C 5/04, 1976 (prototype).