Basf Aktiengesellschaft

Eckhart Wagner

Klaus Volkamer

Ulrich Wagner

Werner Hefner

Wilhelm Ruppel

Thomas Fetzer

Hermann Wistuba

Bernhard Otto

Wolfgang Vodrazka

Volker Schumacher

Gert Burger

Emil Roth

Method of removing nitrogen oxides from a gas flow

Gases containing CO.sub.2 and/or H.sub.2 S in a first absorption stage, at from 40.degree. to 100.degree. C., with an aqueous absorption liquid containing from 20 to 79% by weight of methyldiethanolamine, the gas obtained at the top of the first absorption stage is fed to a second absorption stage in which, it is treated at from 30.degree. to 90.degree. C. with an aqueous absorption liquid which contains from 20 to 79% by weight of methyldiethanolamine and has a lower content of CO.sub.2 and/or H.sub.2 S than the absorption liquid fed into the first absorption stage, the treated gas is taken off at the top of the second absorption stage, the aqueous absorption liquid obtained at the bottom of the second absorption stage and preladen with CO.sub.2 and/or H.sub.2 S is fed to the top of the first absorption stage, the aqueous absorption liquid obtained in the lower part of the first absorption stage and laden with CO.sub.2 and/or H.sub.2 S is let down in two or more flash stages in order to regenerate it, the final flash stage being operated under reduced pressure, a stream of absorption liquid obtained at the bottom of the final flash stage is recycled to the first absorption stage, a further stream of absorption liquid obtained at the bottom of the final and/or penultimate flash stages is fed to a stripping zone for further regeneration, and the regenerated absorption liquid obtained at the bottom of the stripping zone is recycled to the second absorption stage.

Removal of CO.sub.2 and/or H.sub.2 S from gases

CO.sub.2 and/or H.sub.2 S are removed from gases which contain CO.sub.2 and/or H.sub.2 S by a process in which the said gas is treated, in an absorption stage at from 40.degree. to 100.degree. C., with an aqueous absorption liquid containing from 20 to 70% by weight of methyldiethanolamine, the treated gas is taken off at the top of the absorption stage, the aqueous absorption liquid laden with CO.sub.2 and/or H.sub.2 S is taken off at the bottom of the absorption stage and then regenerated by being let down in one or more flash stages, the flash gases being taken off at the top of the flash stage or flash stages, the losses of water as a result of water present in the gas streams taken off at the top of the absorption stage and of the flash stage or flash stages are compensated by feeding in, at the bottom of the last flash stage or, where only one flash stage is used, at the bottom of this, and amount of steam corresponding to the water loss, and the regenerated absorption liquid is recycled to the absorption stage.

CO.sub.2 and/or H.sub.2 S are removed from gases which contain CO.sub.2 and/or H.sub.2 S by means of an aqueous absorption liquid containing an alkanolamine, by a process wherein the said gas is treated, in an absorption stage, at from 40.degree. to 100.degree. C., with an aqueous absorption liquid containing from 20 to 70% by weight of methyldiethanolamine, the treated gas is taken off at the top of the absorption stage, the aqueous absorption liquid laden with CO.sub.2 and/or H.sub.2 S is taken off at the bottom of this stage and is regenerated by being let down in two or more flash stages, and the final flash stage is operated under reduced pressure and the regenerated absorption liquid is recycled to the absorption stage.

CO.sub.2 and, where relevant, H.sub.2 S are removed from natural gases which contain CO.sub.2 and may or may not contain H.sub.2 S by a process in which the said natural gases are treated, in an absorption stage at from 40.degree. to 100.degree. C., with an aqueous absorption liquid containing from 20 to 70% by weight of methyldiethanolamine, the treated natural gases are taken off at the top of the absorption stage, the aqueous absorption liquid laden with CO.sub.2 and, where relevant, H.sub.2 S is taken off at the bottom of the absorption stage and then regenerated in one or more flash stages, and the regenerated absorption liquid is recycled to the absorption stage.

Removal of CO.sub.2 and H.sub.2 S from natural gases

A process for removing condensable aliphatic hydrocarbons and acidic gases such as H.sub.2 S, CO.sub.2 and COS from natural gas containing these, wherein the natural gas is initially treated with polyethylene glycol dialkyl ethers, as the solvent, in a first absorption stage to effect absorption of the condensable aliphatic hydrocarbons; the natural gas drawn off from the first absorption stage is then treated with polyethylene glycol dialkyl ethers, as the solvent, under superatmospheric pressure in a second absorption stage, the acidic gases being completely or partly absorbed; the solvent charged with the condensable aliphatic hydrocarbons which is obtained from the first absorption stage is treated with water in an extraction stage, to form a hydrocarbon phase containing the condensable aliphatic hydrocarbons and an aqueous dialkyl ether phase, and the hydrocarbon phase is separated from the aqueous dialkyl ether phase. The solvent charged with acid gases which is obtained from the second absorption stage is regenerated by expansion and/or stripping in a regeneration stage and the regenerated solvent is recycled to the absorption.

Removal of condensable aliphatic hydrocarbons and acidic gases from

A process for simultaneously removing water and hydrogen sulfide from gases containing both of these by treating the gases, in an absorption zone under superatmospheric pressure, with polyethylene glycol dialkyl ethers as a solvent, stripping the hydrogen sulfide from the loaded solvent, obtained from the absorption zone, in a desorption zone, removing the water, taken up in the absorption zone, from the solvent and recycling the regenerated solvent to the absorption zone, wherein the solvent additionally contains from 0.01 to 20% by weight, based on the solvent mixture, of an alcohol or ether boiling in the range from 50.degree. to 140.degree. C.

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Ludwigshafen, Germany

Eckhart Wagner