A process and a plant for the continuous conversion of a hydrocarbonaceous feed gas into a synthesis gas comprising carbon monoxide and hydrogen, wherein the H.sub.2/CO molar ratio of the product gases can be varied within a wide range. This is achieved in that at least a part of a methane-rich gas obtained during the fractionation of the raw synthesis gas is admixed to the feed gas mixture, and that in the alternative at least a part of the H.sub.2 product gas and/or a fraction of a hydrogen-rich gas increased with respect to the normal operation of the process is admixed to the heating gas mixture, in order to lower the H.sub.2/CO ratio, or at least a part of the CO product gas and/or a fraction of a carbon monoxide-rich gas increased with respect to the normal operation of the process is admixed to the heating gas mixture, in order to increase the H.sub.2/CO ratio.

A system and method for producing acetic acid, including dry reforming methane with carbon dioxide to give syngas, cryogenically separating carbon monoxide from the syngas giving a first stream including primarily carbon monoxide and a second stream including carbon monoxide and hydrogen. The method includes synthesizing methanol from the second stream via hydrogenation of carbon monoxide in the second stream, synthesizing dimethyl ether from the methanol, and generating acetic acid from the dimethyl ether and first-stream carbon monoxide.

In a method for producing a gaseous mixture of CO and H.sub.2, a first gas comprising at least 50% CO is compressed in a first compressor to form a first compressed gas cooled to a first temperature and mixes with a second gas comprising at least 50% hydrogen in order to form the gaseous mixture, at least one of the first and second gases originating from a cryogenic distillation separation unit in which a feed gas containing H.sub.2 and CO cools in a first heat exchanger and is separated in at least one distillation column and at least one part of the second gas heats in the separation unit to a third temperature lower than the first temperature and is then sent to mix with the first gas.

A process and plant are proposed for separating a feed mixture predominantly or exclusively containing carbon monoxide and hydrogen, in which the feed mixture is subjected to a cryogenic separation process in which a carbon monoxide-rich liquid and at least one residual gas mixture which is depleted in carbon monoxide and enriched in hydrogen, in comparison with the feed mixture, are formed. It is intended that the at least one residual gas mixture is subjected to a membrane separation process in which at least one hydrogen-rich permeate and at least one carbon monoxide-rich retentate are formed, wherein the or at least one of the carbon monoxide-rich retentates is recirculated to the cryogenic separation process.

Hydrogen production processes with recovery of liquid or super-critical carbon dioxide using a CO.sub.2 fractionation column are described. The processes use liquid or super-critical carbon dioxide-enriched product from the carbon dioxide recovery system to chill compressed tail gas upstream of a dehydration unit. The warm CO.sub.2 leaving the chiller is returned to the fractionation column as stripping vapor.

A process and apparatus for separating a feed containing hydrogen, carbon monoxide, methane, and optionally nitrogen to form a product gas having a desired H.sub.2:CO molar ratio and optionally a hydrogen product gas and a carbon monoxide product gas. The feed is partially condensed to form a hydrogen-enriched vapor fraction and a carbon monoxide-enriched liquid fraction. The hydrogen-enriched vapor fraction and carbon monoxide-enriched liquid fraction are combined in a regulated manner to form an admixture, which is cryogenically separated to form the product mixture having the desired H.sub.2:CO molar ratio.

The present invention relates to a cold box cycle which allows for independent control of the heat supplied for reboilers associated with the separation columns. More specifically, the invention relates to the tight control of the hydrogen removal separation, thus avoiding the possibility of excess reboiling in this separation. Optimal reboiling also results in a lower temperature of the hydrogen depleted liquid from this separation. As this stream is used to provide a portion of the cooling at the cold end of the primary heat exchanger, lower temperatures facilitate cooling of the incoming syngas feed, reducing carbon monoxide (CO) losses into the crude hydrogen stream from the high pressure separator. Lower CO in the crude hydrogen allows for smaller hydrogen purification equipment.

A system and method for producing acetic acid, including dry reforming methane with carbon dioxide to give syngas, cryogenically separating carbon monoxide from the syngas giving a first stream including primarily carbon monoxide and a second stream including carbon monoxide and hydrogen. The method includes synthesizing methanol from the second stream via hydrogenation of carbon monoxide in the second stream, synthesizing dimethyl ether from the methanol, and generating acetic acid from the dimethyl ether and first-stream carbon monoxide.

The present application relates to a production plant comprisinga synthesis gas generation step (1) arranged to receive a hydrocarbon or carboneous feedstock (2) and in a synthesis gas generation process provide a syngas, a production step (4) arranged to receive the syngas and produce a product stream (5), a reverse water gas shift step (4) arranged to receive a H2 rich gas stream (7) and a C02 feed (8) and in a RWGS step obtain a reverse shifted gas stream (9), andmeans (10) for adding said reverse shifted gas stream (9) to the synthesis gas stream (3).

A method for separating a feed gas, containing nitrogen and carbon monoxide as main components, in a distillation column: the feed gas is cooled in a heat exchanger; at least a portion of the feed gas, or at least a portion of a gas derived from the feed gas, is sent to a reboiler of the distillation column so as to condense the gas while producing a liquid, and optionally a gas; at least a portion of the liquid is sent to the distillation column; a nitrogen gas-rich flow is extracted from the distillation column; a carbon monoxide-rich flow is extracted from the distillation column, heated in the heat exchanger, and compressed so as to provide a carbon monoxide-rich material at production pressure.