Linde Aktiengesellschaft

Eberhard Lassmann

Heinz Karwat

Franz Beran

Christian Benkmann

Karl Baur

Nicole Schodel

Holger Hackner

Peter Kohler

Robert Helmling

Hans J Gerhards

For recovering acetylene from hydrocarbons, the hydrocarbons are thermally cracked in the presence of CO.sub.2 as a diluent gas. Suitable for thermal cracking for acetylene generation is a ratio, by weight, of CO.sub.2 to hydrocarbon, of between 3:1 and 1:3, and preferably between 2:1 and 1:2. It is preferred for the CO.sub.2 to be mixed with the hydrocarbons before thermal cracking which is thereafter conducted at average reaction temperatures of between 800.degree. and 1200.degree. C., preferably between 900.degree. and 1100.degree. C. An average residence time of between 5 and 500 milliseconds (ms) of the hydrocarbons during thermal cracking has proven to be effective. As the hydrocarbon feedstock for the thermal cracking, basically C.sub.2+ alkanes, especially ethane, propane and/or butane, can be used advantageously. After the cracked gas is cooled, higher alkynes are removed from the cracked gas, then the acetylene is separated preferably by scrubbing with an absorption agent selective for acetylene. Recycle streams of hydrocarbons and/or CO.sub.2 for the thermal cracking can contribute to savings and more efficient use of the feedstock.

Process for recovering acetylene from hydrocarbons by thermal cracking

A process is described for scrubbing of NO.sub.x and/or SO.sub.2 from waste gases as, e.g., flue gases, which employs a scrubbing agent comprising Fe(II) ions in nonaqueous solvents. The scrubbing agent can be regenerated after its loading simply by heating and/or reduction of pressure, after which the scrubbing agent can be reused. A slight reduction of the Fe(II) ion concentration occurring by oxidation can be balanced by simple means. The process makes it possible to scrub out NO or NO.sub.x alone or together with SO.sub.2. If SO.sub.2 alone is to be scrubbed out of a gas mixture, addition of Fe(II) salt can be eliminated.

Process for scrubbing of NO and/or SO.sub.2 from gas mixtures

In the removal of sour gases by scrubbing with an aqueous alkali metal salt solution, e.g. a solution of K.sub.2 CO.sub.3, the circulating scrubbing liquid is gradually contaminated with organic acids, especially formic acid, which in turn ties up K.sup.+ as the formate which is ineffective for scrubbing purposes. To remove the organic acids, at least a partial stream of the circulating scrubbing liquid is subjected to an oxidation step under conditions leading to the oxidation of the salts of the organic acids, thereby liberating the bound alkali metal ions. If the scrubbing liquid contains an oxidizable activator, the latter can be extracted prior to oxidation of the scrubbing liquid and added back subsequent to the oxidation.

Process for removal of sour gases by scrubbing

A process for providing a feed gas for a chemical reaction and for separating a gaseous reaction product from the gaseous mixture obtained by the reaction, wherein the feed gas is obtained by the fractionation of a crude gas mixture containing this feed gas proper, as well as a carrier gas or carrier gas mixture, and is reacted only incompletely in the reaction, and wherein the unreacted proportion is to be recycled into the reaction, the improvement wherein the fractionation of the crude gas mixture and the separation of the gaseous reaction product are conducted in a single adsorption plant operating by the pressure swing method and containing cyclically reversible adsorbers.

Process for providing a feed gas for a chemical reaction and for the

A process for scrubbing acid gases, especially carbon dioxide, from gas mixtures with an aqueous amine solution serving as the scrubbing liquid in which hexamethylene diamine serves as the amine. The concentration of the hexamethylene diamine in the aqueous solution is 5 to 40% by weight, preferably 25 to 35% by weight.

Method of scrubbing acid gases from gas mixtures

Aqueous glycol solutions, used for example, in the de-icing of heat exchange surfaces used in defogging systems, are regenerated by freeze crystallization, the ice being separated with relatively little loss of glycol.

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Herrnhausen, Germany

Eberhard Lassmann