Metallgesellschaft Aktiengesellschaft

Gerhard Hochgesand

Manfred Kriebel

Hans-Martin Stonner

Alexander Doerges

Emil Supp

Friedemann Marschner

Paul Wiesner

Gerhard Grunewald

Karl Bratzler

Heinz Hiller

Heinz Kahles

A condensate which contains cyanide ions, hydrogen sulfide and ammonia is first partly purified by stripping with water vapor and stripped-off gases are then scrubbed with an absorbent. The laden absorbent contains 50 to 300 grams ammonia and 10 to 100 grams hydrogen sulfide and is at a temperature of 70.degree. to 150.degree. C. and has a pH value of at least 9. Sulfur is added to the condensate or the laden aqueous absorbent in a quantity which is at least 0.8 times the quantity that is stoichiometrically required to convert the cyanide ions to thiocyanate ions. The sulfur may be produced from hydrogen sulfide and oxygen, preferably in the presence of an oxidation catalyst. Alternatively, the sulfur may be added to a liquid which contains 10 to 400 grams ammonia and/or ammonium ions per liter so that ammonium polysulfide is formed. That solution is mixed with the liquid that contains cyanide ions.

Process for the treatment of an aqueous condensate

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

Methanol is produced by a process wherein

Process for producing methanol

Growing community of inventors

Neu Isenburg, Germany

Gerhard Hochgesand