Metallgesellschaft Aktiengesellschaft

Alexander Doerges

Johann Schlauer

Manfred Kriebel

Karl Bratzler

Georg Kempf

Anton Hude

Paul Rudolph

Heinz Hiller

Gerhard Hochgesand

Johannes Schlauer

Karl Braizler

Vaclav Svoboda

Winfried Zeschmar

The gas which contains sulfur compounds consisting of H.sub.2 S and/or COS is scrubbed with an absorbent solution which contains at least one amine. The gas to be desulfurized which enters the scrubbing zone is at a temperature in the range of 25.degree. to 100.degree. C. and rises in the scrubbing zone in a countercurrent to the scrubbing solution. The gas leaving the absorbent solution is indirectly cooled to a temperature which is at least 20.degree. C. below the entrance temperature of the gas and is not below 5.degree. C. The indirect cooling results in a condensate, which contains at least one secondary amine. That condensate is passed through the scrubbing zone as an absorbent solution. The condensate leaving the scrubbing zone contains at least 10 moles secondary amine and preferably at least 100 moles secondary amine per mole H.sub.2 S and COS in the gas to be desulfurized. The gas to be desulfurized suitably contains secondary amine used in the absorbent solution as well as an organic solvent, such as methanol, ethanol or isopropanol.

Process of desulfurizing gases with an amine-containing absorbent

In a process of regenerating laden absorbent solutions used to desulfurize gases which contain H.sub.2 S and CO.sub.2 and possibly COS, which solutions contain at least one highly volatile secondary amine in an organic solvent, the laden absorbent solution is flashed and stripped with its own vapor. The overhead vapors from the regenerator, which consists of an indirectly heated plate column, are cooled to approximately ambient temperature. The resulting condensate is separated and fed to the top of the regenerator. The cooled gas is withdrawn. A partial stream of the vapor is withdrawn from the regenerator 1 to 10 plates below the outlet for the overhead vapors and the inlet for the condensate and is cooled to ambient temperature. The resulting condensate is fed to the regenerator 1 to 10 plates above the inlet for the absorbent solution. The remaining gas is fed to a re-absorber, in which it is scrubbed in a counter-current operation with at least one partial stream of the absorbent solution, preferably with the effluent from the desulfurization COS. The exhaust gas is withdrawn from the top of the re-absorber. The absorbent solution drained from the re-absorber is fed to the upper portion of the regenerator. The regenerated absorbent solution is withdrawn and used to desulfurize gases which contain H.sub.2 S and CO.sub.2 and possibly COS.

Process of regenerating absorbent solutions for sulfur-containing gases

The process of removing H.sub.2 S, CO.sub.2, COS and mercaptans from gases by absorption in an absorbent solution, which is circulated between the absorbing zone and a regenerating zone and which contains at least one organic base dissolved in methanol, has been improved. In accordance with the invention, the absorbent solution contains one or more secondary or tertiary amines general formula R.sub.1 --NH--R.sub.2 or (R.sub.1).sub.2 --N--CH.sub.2 --N--(R.sub.2).sub.2, wherein R.sub.1 and R.sub.2 means CH.sub.2 -- or --CH.sub.2 --CH.sub.3 or CH.sub.3 --CH--CH.sub.3 in a total amount of at least 0.5 to 5.0 moles per liter, and the amine has or the amines have a boiling point between 40.degree. and 110.degree. C. at 1 bar. This improvement permits a selective removal of H.sub.2 S from CO.sub.2 -containing gases.

Process of removing H.sub.2 S, CO.sub.2, COS and mercaptans from gases

An improvement in a process of regenerating a hydrocarbon laden water miscible high boiling organic solvent obtained by scrubbing a hydrocarbon-containing gas with said water miscible high boiling organic solvent at normal temperature and super atmospheric pressure, wherein the laden solvent is regenerated by flashing, heating and/or stripping, cooled and recycled to the scrubbing step, the improvement comprising:

Process of regenerating laden absorbents

In a process of selectively desulfurizing gases which contain hydrogen sulfide and carbon dioxide comprising scrubbing the gases with an aqueous potassium carbonate solution under superatmospheric pressure and at temperatures of about 100.degree. C., regenerating the laden scrubbing solution and recycling the regenerated scrubbing solution, the improvement wherein the gases to be purified are scrubbed with an aqueous potassium carbonate solution so as to maintain a mass ratio of 1.0 to 3.0 vals (gram equivalents) of alkali in the solution per mole of CO.sub.2 and H.sub.2 S in the gases to be purified, the laden scrubbing liquor is subsequently regenerated by being stripped with a gas in which a CO.sub.2 partial pressure above 0.2 bar is maintained, and the so regenerated scrubbing solution is recycled.

Process of selectively desulfurizing gases

A process for the selective removal of hydrogen sulfide from a gas containing hydrogen sulfide and carbon dioxide wherein said gas is contacted at superatmospheric pressure with an alkali metal carbonate solution, the resultant solution which contains hydrosulfide and bicarbonate is subjected to pressure reduction, the total alkali metal bicarbonate content of the resultant solution is adjusted so that it is at least 55% of the total alkali content of the solution and the said solution is then stripped and recycled to the hydrogen sulfide absorption step.

Process of regenerating alkali carbonate solutions formed by the

A process for the removal of hydrogen cyanide and of metals which form carbonyls from gases produced by partial oxidation of hydrocarbons with steam and oxygen is described involving use of an alkaline solution containing a carbonyl inhibitor in the scrubber.

Process of purifying gases

An improvement in a process for regenerating a water-containing, highly volatile organic solvent which has been used to scrub acid constituents from gases having a low content of water and of volatile compounds of the 8th group of the Periodic System is disclosed. According to the process, solvent which contains absorbed acid constituents is regenerated in a regeneration zone by heating the same to drive off acid constituents and deacidified solvent is recycled in the scrubbing process. According to the invention the solvent is contacted during the regeneration with a complexing agent soluble in the solvent in an amount of 0.005 to 1 gram complexing agent per liter of solvent. A branch stream is removed from the regeneration zone which branch stream contains volatile solvent, water and metal salts dissolved in the water. The branch stream is subjected to distillation to remove overhead the volatile solvent which is returned to the regeneration zone and to leave behind an aqueous solution of the metal salt. A compensating amount of water is added to the solvent cycle.

Process for regenerating water-containing methanol

In scrubbing fuel gases or synthesis gas, absorption is improved by using simple oxygen containing water soluble organic compounds such as the lower alcohols, butanols, or water soluble lower ethers.

Process of scrubbing fuel synthesis gases to remove acid gases and

A process for purifying gases produced by the gasification of fossil fuels by a treatment with water vapor and oxygen under superatmospheric pressure. The raw gas produced is treated to remove catalyst-deteriorating impurities such as mono- and polyunsaturated hydrocarbons, mercaptans, HCN, HCl, H.sub.2 S, CS.sub.2, COS, and NH.sub.3, and to desulfurize the gas to produce an exhaust gas which is rich in H.sub.2 S. The gas is cooled and scrubbed under superatmospheric pressures and at normal temperatures. The raw gas, at a temperature of 150.degree.-170.degree. C., is indirectly cooled to ambient temperature. The condensible hydrocarbons are then separated and removed, and the gas is then scrubbed with water to remove ammonia in a first scrubbing stage wherein the rate of water addition is controlled to be just sufficient to remove the ammonia. The gas is then scrubbed with a high-boiling organic solvent which is miscible with water and to which sulfur has been added in a second scrubbing stage in which the rate of solvent addition is controlled in dependence on the solubility of the methyl mercaptan, which is to be removed, in the solvent. The gas is scrubbed with the same solvent in a third scrubbing stage in which the water content of the solvent is kept at 5-30 mol percent H.sub.2 O in which H.sub.2 S and COS are entirely and selectively removed from the gas. Lastly, the scrubbing agents from the second and third scrubbing stages are separately regenerated and recycled to the second and the third scrubbing stages for re-use.

Process for purifying gases from the gasification of fossil fuels

A process of purifying gases produced by a gasification of fossil fuels wherein the gas is cooled and scrubbed under superatmospheric pressures at normal temperatures while the raw gas, at a temperature of 150.degree.-170.degree. C, is indirectly cooled to ambient temperatures, the condensible hydrocarbons are separated and removed, the gas is scrubbed with water to remove ammonia in a first scrubbing stage in which the rate of water addition is controlled to be just sufficient to remove the ammonia, the gas is then scrubbed with a high-boiling organic solvent which is miscible with water and to which sulfur is added, the gas is subsequently scrubbed with the same solvent in a third scrubbing stage in which the water content of the solvent is kept at 5-30 mole percent H.sub.2 O and in which H.sub.2 S and COS are entirely removed from the gas, and the scrubbing agents from the second and third scrubbing stages are separately regenerated and recycled to the second and third scrubbing stages. The scrubbing agent used in the second scrubbing stage is flashed approximately to atmospheric pressures, adding water, heating the scrubbing agent to the boiling temperature but not in excess of 170.degree. C, treating the scrubbing agent in a stripping column with water vapor or stripping gas to remove liquid impurities, condensing the mixed vapors, isolating the condensates by phase separation, and feeding part of the aqueous phase as a reflux to the upper portion of the stripping column while the stripped scrubbing agent is cooled and is fed back to the top of the second scrubbing stage.

Process of purifying gases produced by the gasification of solid or

A process for desulfurization of fuel or synthesis gases containing carbon oxysulfide wherein the carbon oxysulfide is hydrolyzed by treating the gas at a temperature of 50.degree. to 105.degree.C with a low-volatility organic solvent inert to the carbon oxysulfide and containing 15 to 50 mole-percent water, the hydrolysis products and other sulfur-containing compounds being removed by subsequent scrubbing of the gas.

Process for the desulfurization of gases

Gases produced by reacting fuels with oxygen containing gases and water vapor under pressure are desulfurized by scrubbing with a concentrated solution of one or more alkali salts of weak inorganic acids at a temperature near the atmospheric-pressure boiling point of the solution in a column while maintaining an exchange ratio of from 0.2 to 2.0 cubic meters of the concentrated solution per standard cubic meter hydrogen sulfide in the gas to be purified.

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Frankfurt am Main, Germany

Alexander Doerges