Metallgesellschaft Aktiengesellschaft

Linde Aktiengesellschaft

Manfred Kriebel

Alexander Doerges

Johann Schlauer

Herbert Fischer

Gerhard Grunewald

Karl Bratzler

Anton Hude

Ulrich Heinrich Sander

Joachim Wilhelm

Karl-Heinz Eisenlohr

Gerhard Hochgesand

Heiner Tanz

Hans Gaensslen

Ulf Jauernik

Hans-J Fritzsche

An H.sub.2 S-containing gas is combusted with oxygen in at least one burner, which discharges into a combustion chamber. The resulting mixed gases contain H.sub.2 S, SO.sub.2, free hydrogen and elementary sulfur and are at temperatures of about 900.degree. to 2000.degree. C. At temperatures of about 900.degree. to 2000.degree. C. at least part of the free hydrogen is removed from said mixed gases. The free hydrogen may be removed from the mixed gases, e.g., through membranes.

Process of combusting an H.sub.2 S-containing gas

A scrubbing solution boiling above 100.degree. C. under atmospheric pressure is used for removing H.sub.2 S and CO.sub.2 from a gas stream at a temperature from 5.degree. to 70.degree. C. The solution is thus laden with at least CO.sub.2 and H.sub.2 S. For regeneration, the laden scrubbing solution under a pressure of at least 2 bars and at a temperature of at least 60.degree. C. is supplied to an expansion zone and is expanded therein. A flashed-off gas which is rich in H.sub.2 S is withdrawn from the expansion zone. The scrubbing solution from the expansion zone is subjected to a hot regeneration, by which the scrubbing solution at a temperature below its boiling temperature is stripped with an inert gas so that its residual loading is substantially removed. Mixed gases which contain inert gas are withdrawn from the hot regeneration and are contacted with scrubbing solution.

Process of regenerating a high-boiling scrubbing solution which contains

A natural gas, which in addition to methane contains 2 to 4 carbon atoms per molecule and H.sub.2 S, is treated to remove the H.sub.2 S and the hydrocarbons in part. The natural gas under a pressure of at least 5 bars is indirectly cooled in a heat exchange zone to temperatures from -30.degree. to 100.degree. C. The condensate is removed from the cooled natural gas and is pressure-relieved and is then passed as a coolant through the heat exchange zone. Scrubbing liquor is cooled in the heat exchange zone to temperatures from -30.degree. to -80.degree. C. and is contacted in a scrubbing zone with the natural gas from which the condensate has been removed. The laden scrubbing liquor which has been withdrawn from the scrubbing zone is passed through the heat exchange zone. The natural gas which has been purified in the scrubbing zone is pressure-relieved and is also passed through the heat exchange zone.

Process for H2S and HC removal from natural gas

A feed gas which contains H.sub.2 S is combusted with oxygen and air in at least one burner, which opens into a combustion chamber. The resulting gas mixture contains H.sub.2 S and SO.sub.2 and is intended to be converted to elementary sulfur by the Claus process. The combustion chamber is supplied with oxygen through a central tube of the burner, with the H.sub.2 S-containing feed gas through a second tube, which coaxially surrounds the central tube, and with air through a coaxial outer tube. The feed gas supplied to the burner contains H.sub.2 S and at least 5% by volume hydrocarbons or CO.sub.2. Velocities of flow of oxygen of 50 to 250 m/sec. and of the H.sub.2 S-containing feed gas of 10 to 30 m/sec. are adjusted at the outlet of the burner. Temperatures in the range from 2000.degree. to 3000.degree. C. are generated in the core zone of the burner flame. A gas mixture which contains at least 2% by volume CO and at least 8% by volume H.sub.2 and is at temperatures from 1350.degree. to 1650.degree. C. is withdrawn from the combustion chamber.

Process of removing hydrogen sulfide from exhaust gas

Two absorbent solution streams are laden with CO.sub.2 and optionally with COS, which are physically dissolved. The COS content of the second absorbent solution stream is at least three times the COS content of the first absorbent solution stream. For regeneration, the first absorbent solution stream is pressure-relieved into a first pressure relief zone so as to reduce the pressure by at least 2 bars and to flash off a gas which contains CO.sub.2. The second absorbent solution stream is pressure-relieved at least in part into a second pressure relief zone, which contains exchange-promoting elements. The flashed-off gas from the first pressure relief zone is passed through the second pressure relief zone in a countercurrent to the second absorbent solution stream. The second pressure relief zone is preferably disposed over the first pressure relief zone and the second absorbent solution stream flows first through the second and then through the first pressure relief zone.

Process for regenerating absorbents containing CO.sub.2 and COS

The feed gas is partially burnt with oxygen-containing gas in a thermal Claus process plant, in which temperatures in the range of 850.degree. to 1350.degree. C. is maintained. Product gas which has been produced is passed through a catalytic Claus process plant (Claus catalysis plant), from which sulfur is withdrawn. The exhaust gas from the Claus catalysis plant is supplied to a desulfurizing plant. The sulfur compounds in the exhaust gas of the desulfurizing plant are converted to SO.sub.2 in a thermal aftertreating unit. When the rate of the H.sub.2 S-containing feed gas is below a limit, which is between 20 to 35% of the total rate of feed gas permissible for the thermal Claus process plant, then recycled exhaust gas from the desulfurizing plant (recycle gas) is admixed to the feed gas at such a rate that the rate of the mixed feed and recycle gases exceeds that limit. The recycle gas is suitably heated to 200.degree. to 400.degree. C. before it is mixed with the feed gas.

Process for removing hydrogen sulfide from exhaust gas and for producing

The liquid sulfur which contains H.sub.2 S is sprayed in a steel vessel and the liberated gases which are rich in H.sub.2 S are withdrawn. A degasification accelerator is added to the liquid sulfur. The steel vessel contains at least two chambers, which communicate with each other and are connected in series. Sulfur at temperatures in the range from 140.degree. to 160.degree. C. is supplied to the first chamber. Sulfur is withdrawn from the second chamber and is cooled to temperatures of 120.degree. to 135.degree. C. outside the vessel. The liquid sulfur which has been cooled is sprayed in the gas space of the first chamber. The sulfur is caused to remain in the steel vessel for a dwelling time of 12 to 32 hours. The gas spaces of the chambers are scavenged with an oxygen-free inert gas. The sulfur is withdrawn from the vessel and sprayed in the gas space of one of the chambers about 30 to 50 times until the dwelling time of the sulfur in the vessel has expired.

Method of degasifying liquid sulfur which contains hydrogen sulfide

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 producing a synthesis gas which has a low inert gas content and is intended for the synthesis of alcohols, particularly of methanol, and of hydrocarbons, and which is produced from coal or heavy hydrocarbons, by a gasification under pressure with oxygen and steam, whereafter the raw gas is cooled, the impurities are removed by a scrubbing with methanol, and the methanol is removed by means of molecular sieves from the cold pure gas. The pure gas is then cooled further and partly liquefied, the remaining gas is further cooled by a pressure relief and methane is distilled from the liquid part with simultaneous recovery of the synthesis gas, which consists of hydrogen and carbon monoxide and has a low methane content. All or part of the methane is compressed and is subsequently reacted with steam and oxygen to produce carbon monoxide and hydrogen. The produced gas is admixed to the synthesis gas or to the partly purified raw gas.

Process of producing a synthesis gas which has a low inert gas content

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

In a process of decreasing the sulfur content of exhaust gases obtained during the recovery of sulfur from acid gases containing H.sub.2 S and other S-containing compounds in the Claus process, the acid gases which contain H.sub.2 S and other S-containing compounds are reacted in a Claus plant to form elemental sulfur. A gas which contains H.sub.2 S or SO.sub.2 is subsequently added at a controlled rate to maintain a stoichiometric ratio of 2:1 of H.sub.2 S to SO.sub.2 in the tail gas from the Claus plant. The gas which contains H.sub.2 S or SO.sub.2 may be added to the tail gas from the Claus plant or before the last contacting stage of a multistage Claus plant. During the addition of a gas which contains H.sub.2 S, the Claus plant can be operated at an H.sub.2 S to SO.sub.2 ratio of or below 2:1. During the addition of a gas which contains SO.sub.2 the Claus plant can be operated at an H.sub.2 S to SO.sub.2 ratio of or above 2:1. The H.sub.2 S and SO.sub.2 contained in the tail gas are chemically reacted to form elementary sulfur in a tail gas-desulfurizing plant and the sulfur is withdrawn.

Process of decreasing the sulfur content of exhaust gases obtained

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 apparatus for the regenerating of absorbent is disclosed wherein the apparatus comprises a regenerating column provided with mass transfer-promoting elements. The regenerating column comprises an upper regenerating zone which can be shut down and is provided with at least one shutoff valve-controlled inlet for laden absorbent and a lower second regenerating zone provided with a second shutoff valve-controlled inlet for the same laden absorbent, the volume ratio of the second regenerating zone to the upper regenerating zone being at least about 1.5:1. A process for regenerating laden absorbent is also disclosed.

Apparatus for regenerating absorbent and method of operating the

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

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.

Growing community of inventors

Frankfurt am Main, Germany

Manfred Kriebel