DE2558754A1 - Removing hydrogen sulphide from coke oven gas - by treating with recycled ammonia water in which the hot ammonia water is stripped through purified gas fraction - Google Patents

Abstract

Hydrogen sulphide is removed from coke oven gas by using recycled ammonia-water in which NH3 contg. gas is fed to the H2S scrubber, the regenerated hot ammonia-water being stripped through purified coke oven gas and the thus NH3 enriched gas is passed to an intermediate and/or final wash stage of the H2S washer. A fraction of the treated coke oven gas taken from the delivery side of the suction unit serves as purified gas and the H2S washer is located on the suction side of the gas stream. Process does not require a supply of high purity ammonia to the final wash stage, which involves high heat and vapour consumption, and is thus more economical.

Description

Procedure for removing sulphurous water

material from gases, especially coke oven gas.

The invention relates to a method for removing hydrogen sulfide from gases, in particular coke oven gas, by means of circulating ammonia containing Water in which the gas containing NH3 is fed to the 112S washer.

Such a method is known from DT-OS 1,669,323. at This process, the ammonia raw water is deacidified in a column 10 and the first stage of the H2S scrubber supplied again after cooling. A partial flow of the raw ammonia water is desulfurized in a further column and in a third column of all volatile components freed. Pure ammonia gas is produced from the top of the third column removed and blown into the final stage of the H2S washer.

The use of ammonia water to desulfurize coke oven gas It is advisable because the process uses an absorbent (ammonia) for the removal of H2S can be used.

The solution loaded with H2S is relatively easy to regenerate and irreversible bonds are hardly formed during absorption and regeneration, so that there is hardly any loss of chemicals. Because the binding of the H2S to the ammonia water is relatively weak, but can only partially Sulfurization of the gas can be achieved. Because the ammonia present in the gas faster is dissolved in water than the hydrogen sulphide, had to do with the aforementioned known processes of the final washing stage as pure ammonia as possible are fed, to achieve more extensive desulphurisation. This weakness increases in the known processes, however, the operating costs due to increased heat or steam consumption, since the production of pure ammonia vapors results in the production of strong ammonia water is a prerequisite.

The object of the invention is therefore to create a method with which is an extensive desulphurization of gases, especially coke oven gas The lowest possible operating costs are achieved.

This object is achieved according to the invention by the fact that regenerated hot ammonia water is stripped by purified coke oven gas and that with NH3 enriched KO # '# oven gas of an intermediate and / or final washing stage of the X Washer feeds. The cleaned coke oven gas flow takes place while flowing through of the stripper removes ammonia from the regenerated ammonia water. The one from the stripper ammonia water that runs off is fed to the H2S scrubber after heat exchange and cooling. This measure achieves an H2S limit value in the coke oven gas of 1 to 0.7 g / Nm3, without a substantial increase in steam consumption, as is the case, for example desulfurization to 2 to 1.5 g / Nm3 is required.

A partial gas stream is preferably used as the purified coke oven gas of the in-process desulphurized gas itself. For this purpose, about 1 to 2% of the total taken from the head of the H2s washer Desulfurized gas used as a partial gas flow.

The H2S scrubber is preferably arranged in the gas flow on the suction side, and the partial gas flow is branched off from the pressure side of the suction cup.

Other features, advantages and uses of the present Invention emerge from the following description of an exemplary embodiment of the method according to the invention using the enclosed scheme of procedure.

Line 1 becomes the lower washing stage of H2S washer 2 cooled coke oven gas, which contains about 9 g H2S / Nm3 and 6 g NI # 3 / Nm3, is supplied. Regenerated ammonia water is fed to the H2S scrubber via a line 3 and the main amount of H2S is absorbed from the coke oven gas in countercurrent. In the Following scrubbing stage 4, gas condensate is used as absorption liquid via line 5 fed. In a final washing stage 8, fresh water or from the ammonia washer is used incoming water, which is supplied via line 9, as absorption liquid. The washing liquid of the final stage is used to remove the condensation and solubility 8 circulated through a cooler 11. The weakly enriched liquid is over a line 12 is fed to the lower washing stage of the H2S washer 2. The desulphurized Gas is fed to the ammonia scrubber via line 13.

A partial flow is branched off via line 14 and to a stripper 7 led. Enriched gas condensate is via a line 15 together with a Partial flow of the enriched ammonia water from line 16 according to the via the line 9 added amount of liquid via a preheater 17 to a Abortionist 18 given. There the volatile constituents become NH3 and H2S expelled from the liquid by the addition of water vapor. Be overhead the vapors drawn off through line 20 and passed into a deacidifier 21 and to regenerate the other partial flow supplied via lines 22 and 23 of the ammonia water used for H2S leaching. At the deacidifier's head 21 a vapor containing ammonia and hydrogen sulphide is drawn over the pipe 24 withdrawn for further processing.

The regenerated ammonia water occurring in the deacidification sump is pumped to the stripper 7 via the line 25. In countercurrent is the over the Line 14 branched off pre-cleaned coke oven gas partial flow is blown through the stripper 7. The coke oven gas is enriched with NH3 and is transferred to the scrubbing stage via line 6 4 of the H2S scrubber 2 is supplied to the NH3 required for the H2S scrubbing there -Quantity to be added.

A partial gas stream of the UH3-enriched coming from the stripper 7 Coke oven gas is fed to the final washing stage 8 of the H2S washer 2 via line 1G, to provide the amount of NH3 required for the final washout.

The regenerated ammonia water obtained in the bottom of the stripper 7 becomes after heat exchange with the partial flow of the enriched ammonia water Line 23 in the heat exchanger 26 and after cooling in the cooler 27 in the H2S washer 2 pumped back.

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Claims (3)

Claims: 1. Process for removing hydrogen sulfide from gases, in particular coke oven gas, by means of circulating ammonia-containing Water in which the H2S scrubber is supplied with gas containing NH3, characterized in that that the regenerated hot ammonia water is stripped by purified coke oven gas and the oksofegas enriched in this way with N113 from an intermediate and / or land wash stage of the washer. 2. The method according to claim 1, characterized in that as purified coke oven gas a partial gas flow of the desulphurized process-specific Gas used. 3. The method according to claim 1 or 2, dadurcll characterized in that the Fi2S washer is arranged in the gas flow on the suction side and the partial gas flow from the The pressure side of the suction cup branches off.