Linde Aktiengesellschaft

Rainer Fabian

Heinz Bauer

Freimut Marold

Herwig Landes

Wolfgang Schmid

Dieter Latzin

In the recovery of a pure CO fraction from a charge containing hydrogen, carbon monoxide and methane from which water and carbon dioxide have optionally been removed, the charge is cooled and partially condensed; and the carbon monoxide is scrubbed out with supercooled liquid methane. The resultant hydrogen is stripped out, and the recovered CO/CH.sub.4 -rich fraction is separated by rectification to obtain a pure CO fraction and a CH.sub.4 -rich fraction. The supercooled liquid methane used as the scrubbing agent contains at least 2 to 15 mol % carbon monoxide, preferably 7 to 10 mol % carbon monoxide. Also, the hydrogen stripper and methane scrubbing column can be combined in a single column.

Process for recovering a pure carbon monoxide fraction

An improvement in a process for the production of high-purity hydrogen and high-purity carbon monoxide by the separation of an extensively dry and CO.sub.2 -free H.sub.2 /CO crude gas mixture, also containing methane, by means of pressure swing adsorption and one-stage partial condensation, wherein, the H.sub.2 /CO crude gas mixture is subjected to a pressure swing adsorption process, producing a high-purity hydrogen product stream, while the CO-rich gas obtained in the regeneration during the pressure swing adsorption process is compressed, cooled, at least partially condensed, and conducted into a phase separator wherein it is separated into a gaseous H.sub.2 -rich fraction and a liquid CO-rich fraction, whereupon the gaseous H.sub.2 -rich fraction is heated and admixed to the H.sub.2 /CO crude gas mixture before the latter is fed into the pressure swing adsorption. The improvement is that at least a portion of the liquid CO-rich fraction from the phase separator is at least partially expanded, heated, and conducted into the lower region of a double distillation column having an upper and lower region, a liquid methane fraction being withdrawn from the bottom of the column, a liquid high-purity carbon monoxide product fraction being withdrawn from the lower part of the upper region of the column, and a gaseous CO-rich fraction being withdrawn from the head of the column.

Process for obtaining high-purity hydrogen and high-purity carbon

For obtaining pure CO from a gaseous mixture, consisting predominantly of hydrogen and carbon monoxide, e.g., that produced by the endothermic catalytic oxidation of hydrocarbons in the presence of CO.sub.2 as the oxygen-yielding agent the gaseous mixture is compressed; residual CO.sub.2 and water are removed by adsorption; the resultant purified gaseous mixture is cooled to condense a predominant portion of CO; the condensed CO is pressure-reduced to remove dissolved H.sub.2 in the gaseous phase, the latter being recycled in gaseous form to the gaseous mixture; a fraction of the remaining liquid CO is partially vaporized and engine expanded to produce refrigeration for the system, and after engine expansion, is recycled to the gaseous mixture upstream of the compressor.

Process and apparatus for obtaining pure CO

Processes for the separation of carbon monoxide from feed gas streams polluted with nitrogen are disclosed, in which the feed gas streams, which preferably include hydrogen and methane therein, are supplied to a distillation column, and including the steps of distilling the feed gas stream to produce as the sump product a first carbon monoxide stream of substantially pure liquid carbon monoxide, and a distillation gas stream containing nitrogen therein, heating the sump in the lower portion of the distillation column by contact with a second carbon monoxide stream, withdrawing the sump product from the distillation column, expanding the withdrawn sump product to reduce its temperature, cooling the distillation gas stream in the upper portion of the distillation column by contact with at least a portion of the expanded sump product, recycling at least a portion of the first carbon monoxide stream to provide the second carbon monoxide stream, and withdrawing at least a portion of the first carbon monoxide stream as a product stream.

Process for the extraction of carbon monoxide from gas streams

In a low temperature process for the fractionation of ammonia synthesis waste gas (N.sub.2, H.sub.2, Ar, CH.sub.4) comprising two successive separating stages and a nitrogen refrigeration cycle for supplying reboiler heat to each of the stages and also liquid nitrogen, wherein nitrogen is compressed in a compressor to a final pressure, cooled, expanded, and partially liquefied, gaseous and revaporized liquid nitrogen being recompressed, the improvement comprising compressing the nitrogen to a medium pressure, e.g., 6-20 bar, withdrawing a portion of resultant medium-pressure nitrogen from the compressor, compressing remaining medium-pressure nitrogen to the final pressure, e.g., 30-50 bar, cooling resultant medium-pressure nitrogen in parallel with resultant final-pressure nitrogen, further cooling the medium-pressure nitrogen by supplying reboiler heat to the two separating columns, expanding resultant cooled medium-pressure nitrogen to at least partially liquefy the same, expanding resultant cooled final-pressure nitrogen to at least partially liquefy the same, and combining both resultant at least partially liquefied nitrogen streams in a phase separator.

Lower pressure fractionation of waste gas from ammonia synthesis

In the fractionation of a gaseous mixture, of hydrogen, methane, and carbon monoxide, comprising a cold methane wash to obtain a gaseous stream of hydrogen and a liquid stream of carbon monoxide and methane, the improvement wherein of the gaseous mixture prior to the methane wash is subjected to a continuous partial condensation at a temperature higher than the cold methane wash, thereby obtaining a gaseous phase fraction and a condensed liquid phase fraction; the gaseous phase fraction is conducted to the methane wash, and the condensed liquid phase fraction is conducted to a stripping column which produces a bottoms product stream of methane and an overhead product stream of hydrogen and carbon monozide. The continuous partial condensation can be conducted either in a single stage or in multiple stages.

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Geretsried, Germany

Rainer Fabian