SU979492A1 - Process for purifying coking gas from acid components - Google Patents

Description

The invention relates to methods for purifying coke oven gas from hydrogen sulphide and hydrogen cyanide with an ammonia solution and can be used in all coking plants.

A known method of purification of coke oven gas from acidic impurities, including washing the gas with ammonia water, removing the last absorbed flue gases from the gas by sampling the heating solution of two vapor fractions with a temperature of 22 ° C and 110 ° C and their subsequent treatment. The absorption solution after stripping from it, of the indicated vapors is returned to the coke oven gas aromywage cycle. The vapor fraction with a temperature, in addition to hydrogen sulfide, contains impurities of ammonia and hydrogen cyanide to be separated from the latter with soft water and the washing liquid is fed into the regenerated ammonia solution.

The vapor fraction with a temperature containing a mixture of water vapor, ammonia and predominantly cyanic Euodoride is mixed with alkali to decompose the latter and pass sequentially through a molten salt of nitric acid,

but the transmission time is heated to 300 ° C, and through activated alumina. During treatment, hydrogen cyanide is converted to ammonia and carbon monoxide. The resulting gas mixture is cooled and supplied by a gas pipeline to the primary refrigerators SI.

The disadvantage of this method is the complexity of the instrumentation of the regeneration process with the selection of two distinct vapor fractions, the stringent conditions for the decomposition of hydrogen cyanide (temperature 300 ° C,

15 use of a catalyst), which considerably complicates and increases the cost of a known process.

Closest to the proposed invention is a method of cleaning

20 coke oven gas from acidic components, including washing the gas with an ammonia solution, regenerating the saturated solution by heating, distilling it out at eO-BOC temperature

25 ammonia and acid gases, condensation of separated components, heat treatment of condensate 110-150 ° C for 15-60 minutes, repeated distillation of ammonia and acid gases and supply of acid gases for further,

30 processing 2}.

The disadvantage of this method is the high temperature (110-150) and the duration (15-60 minutes) of the heat treatment process of the condensate, which requires the installation of apparatus of considerable volume.

The purpose of the invention is to accelerate the process of heat treatment of condensate.

This aim is achieved in that according to the method for cleaning the coke oven gas from acid components comprising promtku gas ammiachnm solution, regeneration of the saturated heating the solution, stripping therefrom the ammonia and acid gases, the condensation vadelennElh components condensate heat treatment, repeated stripping of ammonia and acidic gases vschelenne ammonia and the supply of acidic gases for further processing, 20-70% of acidic gases separated from the condensate, before being sent for processing, is sent to the condensation stage or to the condensate unit heat treatment stage.

This method allowed us to reduce the heat treatment time from 15-60 minutes to 2-50 minutes / respectively.

The additional supply of acidic gases containing hydrogen sulfide into napti, directed to condensation or to condensate sent to heat treatment, leads to an increase in concentration. H 5 5 in the condensate, which allows an increase in the rate of decomposition of hydrogen cyanide during the heat treatment of the condensate and makes it possible to reduce the temperature of the heat treatment of the condensate.

The supply of acidic gases is less than 20% by weight, based on the amount obtained in the separation of acidic gases and ammonia, not. provides a significant increase in the concentration of hydrogen sulfide in the condensate, therefore, the proposed effect is not achieved.

The supply of more than 70% by weight of acid gases to the condensate results in an excess of uncondensed gases, which must be disposed of or returned to the ammonia and acid gases separation column. .Example. Through the pipeline, coke oven gas with a temperature of 30 ° C is fed to an absorber irrigated with ammonia pacTJBopoM, with temperature. After absorption of the acidic components, the solution comes from the sampler, from which it is fed into the regenerator column in two streams. The solution is also fed to the top of the regenerator to maintain the set temperature of the outgoing vapors. The solution is poured into a heat exchanger-heater, in which it is heated to 75 ° C and then the regenerator is fed to the middle part. The temperature in the cube of the regenerator is maintained by supplying steam at a temperature of 110 ° C. Ra ggvor

after desorption of the acidic components is removed from the cubic meter, regenerator and enters the heat exchanger-heater and then fed to the refrigerator, where it is cooled before and enters the collection of the regenerated solution. The solution then enters the absorption. The vapors leaving the generator p) enter the condenser in which they condense. Condensate from the condenser enters the reactor, heated with steam to, Next, the solution enters the column, in which ammonia, hydrogen sulfide and carbon dioxide are distilled off with direct steam, the distillation residue containing hydrogen cyanide decomposition is fed into the mixture. The vapors after the column are fed to the distillation column for separation, ammonia and hydrogen sulfide. From the upper part of the column, the vapors enter the reflux condenser, the acid gases enter the condenser and are processed into sulfur ,. From the bottom of the column, the solution containing ammonia is cooled in the refrigerator and fed to the collection of the regenerated solution.

EXAMPLE 2 Coke gas entering the absorber with a temperature of 30 ° C (g / nme contained in the gas. 4.0 H2S, i2.0 HCN, 49.0 SOHz in the amount of 150 nm / h is treated with ammonia water (contains in solution, g / dm 0.4 NS3, 0.3 HCN, 1.5 WITH) at the rate of 2 dm / nmgas.

Ammonia solution containing NoZ 2.2 g / dm3, HCN M, 1 g / dm3, SOU 3.0 g / dm, after washing the coke oven gas with heating to 110 ° C and the vapor fraction with a temperature of 60 ° С, containing, by weight,% 31.32 NH ,,, 26.9 СО, 8.61 HCN, 13.95 / Н20.

The vapor fraction and sour gases containing HijS (70 wt.%) And CO (20 wt.%) In an amount of 15 are fed to a condenser. The outgoing condensate containing, g / dm 156.9 NHj, 156 N, 3, 167.2, 44.5 HCN, is heated in a hydrolyzer to the pressure of its own vapor and is kept for 30 minutes, while the hydrogen cyanide is hydrolyzed to 100%. Further, ammonia, hydrogen sulfide and carbon dioxide are distilled off from the solution, and the bottoms residue is fed to the mixture. The vapor-gas mixture is separated in a column apparatus, acidic gases containing hydrogen sulfide and carbon dioxide, in an amount of 15 nm / h, are fed to a gas stream directed to condensation, and the remaining 15 acidic gases are fed to sulfur for processing.

The bottom residue from the column containing ammonia is returned to the absorption solution, received for the cleaning of coke oven gas.

The table shows the data on the duration of heat treatment at the same condensate temperature by the known and proposed methods (at 100% conversion of He contained in the condensate).

Claims (2)

The use of the proposed method allows to reduce the size of the hydrolysis reactor, simplify the decomposition process by lowering the hydrolysis temperature, and thereby reduce operating costs. The invention The method of purification of coke oven gas from acidic 4-componentb; including washing the gas with 1 miAn1M solution, regeneration of the saturated solution by heating, distilling from its first and second gases, condensation of the separated condensates, heat treating the condensate, re-distilling ammonia and sour gases, increasing the boiling liquor and putting the water. This is due to the fact that, in order to accelerate the heat treatment process, 20-70% of acidic gases removed from the condensate are fed to the condensation stage or to the condensate before the treatment stage, before being fed for processing. Sources of information taken into account in the examination, 1. Japanese Patent 52-10443, cl. With 10 K, published. 1977. 2. Author's certificate 2.868531 / 23-26, cl. C 10 K 1/08, 1980 (prototype).