DE102006051759A1 - Process and apparatus for decomposing synthesis gas by means of methane scrubbing - Google Patents

Abstract

The invention relates to a method and a device for obtaining a carbon monoxide product (43) consisting essentially of hydrogen (H <SUB> 2 </ SUB>), carbon monoxide (CO) and methane (CH <SUB> 4 </ SUB>). existing feed gas (1), wherein from the feed gas (1) by cooling against process streams to be heated a two-phase Stoffgemiscichen, carbon monoxide and methane-containing gas phase (2a) and a CO-rich, hydrogen and methane-containing liquid phase (13a), and wherein subsequently at least subjecting the H <SUB> 2 </ SUB> rich gas phase containing carbon monoxide and methane (2a) to a cryogenic wash with liquid methane (64) (methane wash). The methane wash is carried out in a heat exchanger (Dephlegmator (E4)), to which the gas phase (2a) of the two-phase mixture in the gas stream to liquid, supercooled methane (64) (methane detergent) from bottom to top through the dephlegmator (E4) is performed and the in the solution of leached out of the gaseous phase substances in Methanwaschmittel released heat (solution heat) in the indirect heat exchange of a, preferably in countercurrent to the Methwaschmittel by the dephlegmator (E4) guided refrigerant (5) is received.

Description

The invention relates to a method and an apparatus for obtaining a carbon monoxide product from a feed gas consisting essentially of hydrogen (H ₂ ), carbon monoxide (CO) and methane (CH ₄ ), wherein a biphasic mixture is produced from the feed gas by cooling against process streams to be heated which consists of a H ₂ -rich, carbon monoxide and methane-containing gas phase and a CO-rich, hydrogen and methane-containing liquid phase, and wherein subsequently at least the H ₂ -rich, carbon monoxide and methane-containing gas phase of a cryogenic scrubbing with liquid methane (methane scrubbing ).

By different production methods, such. As catalytic steam reforming or partial oxidation, are produced from hydrocarbonaceous starting materials, such as natural gas, LPG, naphtha, heavy oil or coal so-called syngas generated synthesis, which consist for the most part of H ₂ and CO, but also methane (CH ₄ ), water (H ₂ O), carbon dioxide (CO ₂ ) and other components, such as. As nitrogen and argon. After purification and decomposition, mainly CO and H ₂ are obtained from the synthesis gas as products and used in industry in manifold ways. For the separation and purification of the two synthesis gas components H ₂ and CO, especially cryogenic processes are used in industrial plants.

Such a cryogenic process, which has long been known to those skilled in the art, is the methane scrubbing, as described for example in the patents EP0017174B1 and EP0317851B1 is described. In this, a feed gas is partially condensed against currents to be heated and the carbon monoxide contained in the H ₂ -rich gas phase washed out in a wash column by means of supercooled, liquid methane and withdrawn hydrogen from the top of the wash column. To recover carbon monoxide as a product, the liquid phase and the loaded methane detergent are subjected to H ₂ -stripping. In the subsequent rectification, CO is finally separated from methane. The clean methane fraction is supercooled, pumped, further supercooled and returned as a detergent in the wash column.

To compensate for detergent losses, it is necessary that the feed gas to be decomposed in a methane wash have a methane content of at least 2 mol%. Usually, the methane wash is used when the feed gas is produced by catalytic steam reforming with subsequent CO ₂ removal and drying, since such feed gas has a sufficiently high methane content.

The solubilities for the substances to be washed increase with increasing detergent temperature from. To the effectiveness a methanol wash to increase, therefore, includes a scrubbing column for removing the heat of solution of the scrubbed substances according to the prior art, one or more intermediate cooling. The intermediate cooling (wash column cooler) are as external plate heat exchangers or designed as integrated, wound heat exchangers, in which liquid CO as a refrigerant is evaporated. The temperature of the methane detergent (or the treated gas) increases on its way through a wash column first, before due to the intercooling is lowered to then - until End of the wash column or until another intermediate cooling - again to increase. The mean detergent temperature is therefore despite the intermediate cooling significantly higher, as the temperature with which the methane detergent in the wash column entry. In such a methane wash thus has a larger amount of detergent be used as it is necessary at a constant detergent temperature would.

There it is the methane wash is a cryogenic process, with temperatures down to -185 ° C, is the entire Methanwascheinrichtung according to the prior art with a heat-insulating Enclosed enclosure (cold box). To minimize the investment costs, trying to make the cold box small and compact at the same time. Currently becomes the size of the cold Box and a. determined by the wash column, which, with a height of up to to 25 m and the associated intercoolers and the connecting lines, a dominant part of the plant represents a Methanwascheinrichtung.

Of the Invention is based on the object, a method and a device specify the type described above, the more effective and cost-effective methane wash allow as it is possible in the prior art.

These The object is achieved procedurally according to the invention that the methane wash in a second heat exchanger (Dephlegmator) performed is, what the gas phase of the two-phase mixture in countercurrent too fluid, supercooled Methane (methane detergent) from bottom to top through the dephlegmator to be led and the solution of gaseous substances in the methane detergent released heat (Solution heat) in indirect heat exchange from one, preferably in countercurrent to the methane detergent through the Dephlegmator guided refrigerant is recorded.

The invention combines the functions of Wash column and wash column condenser in a dephlegmator. The cooling according to the invention ensures that the detergent is passed through the dephlegmator at a substantially constant temperature. Gas scrubbing can therefore - with the same cleaning performance - be carried out with a reduced compared to the prior art detergent amount. This has, in addition to smaller dimensions for the actual washing device and the subsequent, used to clean the loaded detergent system parts, also lower energy consumption for the cryogenic gas separation result.

A Embodiment of the method according to the invention provides that the gas phase of the generated during the cooling of the feed gas two-phase mixture together with the liquid phase in the dephlegmator initiated and separated within the dephlegmator becomes. Inside the dephlegmator, the liquid phase of the biphasic mixture with the countercurrent methane detergent and is brought out of the dephlegmator with it.

A Another embodiment of the method according to the invention provides that that with the cooling the feed gas produced biphasic mixture in one of methane wash upstream separation step in a gas and a liquid phase separated and only the gas phase for leaching of at least Carbon monoxide and methane is introduced into the dephlegmator. By this procedure it is avoided that the CO-rich liquid phase with the methane detergent, the loaded is withdrawn from the dephlegmator, mixed.

Appropriate way is it the one for cooling the dephlegmator used refrigerant to liquid Carbon monoxide, on its way through the dephlegmator at least partially evaporated. A preferred variant of the method according to the invention Provides that product quality condensed carbon monoxide, then liquefied against heated process streams and supercooled and, following a cold-drinking Relaxation, by means of a phase separator in a gas and a Liquid phase separated is, wherein at least a portion of the thus obtained liquid phase as a refrigerant fed to the dephlegmator becomes. Another preferred variant of the method according to the invention that does not look for the cooling needed the dephlegmator CO-liquid phase for the production of peak cold is used within the cryogenic gas separation unit, including it expediently one Product purity containing CO-stream and mixed with this to be cooled against process streams evaporated and warmed becomes.

Around the refrigeration requirement to cover the cryogenic gas separation unit, sees another Variant of the method according to the invention before that product quality condensed carbon monoxide, cooled and heated against process streams to be heated Cooling in a relaxation turbine becomes. At least part of the exiting from the expansion turbine Carbon monoxide (turbine exhaust) is heated against cooled process streams and subsequently in the product quality attributed CO-stream. Appropriate way will both cool off of the expansion turbine Carbon monoxide as well as warming up of the turbine exhaust in the main heat exchanger the cryogenic gas separation unit carried out, with cooled carbon monoxide over a Side outlet from the main heat exchanger is deducted while the turbine exhaust over a lateral feed is introduced into the main heat exchanger.

A further embodiment of the method according to the invention provides that the laden methane scrubbing agent withdrawn from the dephlegmator is fed to an H ₂ -stripping collagen (H ₂ stripper) for stripping off the hydrogen dissolved in the laden methane scrubbing agent. Preferably, the loaded methane scrubbing agent is divided into two partial streams, wherein one of the partial streams is expanded and fed as an intermediate feed into the upper section of the H ₂ stripper, while the second partial stream is expanded, partially evaporated against the process streams to be cooled and as an intermediate feed into the lower section of the H ₂ -Strippers is initiated. In order to reduce the carbon monoxide content of the H ₂ -rich top fraction, and thus to reduce the loss of carbon monoxide, it is further proposed that supercooled liquid CH _{4 is} fed as reflux at the top of the H ₂ -stripper.

Further developing the process according to the invention proposes that a CO-rich gas stream be fed directly into the sump space (below the first floor) of the H ₂ -stripper for heating the H ₂ -stripper, wherein the CO-rich gas stream is preferably around is a part of the turbine exhaust or cooled directly from the CO compressor and cooled against process streams to be heated, but not condensed CO stream. In this process variant can be dispensed with a costly reboiler. In addition, it allows a simple control of the H ₂ -Strippers, which represents a decisive advantage over a solution with reboiler especially during rapid load changes of methane scrubbing. The loss of efficiency this Ver variant compared to a solution with reboiler is minimized by the fact that the CO-rich gas stream is introduced at a pressure in the bottom space of the H ₂ -stripper, which is only slightly above the operating pressure of the H ₂ -Strippers.

A further embodiment of the inventive method provides that the H ₂ -rich withdrawn overhead fraction from the H ₂ stripper, relaxed, warmed against process streams to be cooled and is discharged as residual gas. Preferably, excess, introduced with the feed gas in the methane scrubbing methane of the H ₂ -rich top fraction is mixed after the expansion and prior to warming and evaporated together with this against cooling process streams, warmed and passed on as residual gas.

A further embodiment of the method according to the invention provides that the predominantly methane and carbon monoxide-containing mixture is withdrawn from the bottom of the H ₂ -Strippkolonne and fed to a CO / CH ₄ separation column.

The CO / CH ₄ mixture is preferably divided into two substreams before the CO / CH ₄ separation column and one of the substreams is introduced as an intermediate feed into the upper section of the CO / CH ₄ separation column, while the second substream is depressurized against the process streams to be cooled evaporated, warmed and introduced as an intermediate feed into the lower section of the CO / CH ₄ separation column.

A further embodiment of the method according to the invention provides that the bottom product from the CO / CH ₄ separation column, which is methane containing detergent quality, is removed, subcooled against process streams to be heated, brought to pressure by means of a pump, further subcooled against process streams to be heated and preferably divided into three sub-streams, wherein one of the partial streams as methane scrubbing the Dephlegmator and another partial flow as reflux is fed to the H ₂ -tripper, while the third partial stream withdrawn as excess methane from the methane cycle and preferably the H ₂ -rich, from Head of H ₂ -stripper withdrawn fraction mixed and is passed as residual gas from the Methanwäsche.

Another embodiment of the process according to the invention provides that the overhead product of the CO / CH ₄ separation column, which is carbon monoxide having product purity, is heated against process streams to be cooled and then compressed in a compressor to product pressure. Also product purity carbon monoxide streams within the cryogenic gas separation unit, such as CO streams that are not or no longer needed for the cooling of the dephlegmator are suitably admixed to the top product of the CO / CH ₄ separation column prior to its warming.

If the feed gas has an H ₂ / CO ratio of more than three and / or the feed gas is under a pressure of less than 25 bar, an advantageous variant of the method according to the invention provides that product carbon monoxide condenses in the lower part of the main heat exchanger, subcooled, then expanded in a phase separator and there separated into a gas and a liquid phase. The liquid phase is withdrawn from the phase separator and used to produce peak cooling to cool the feed gas. Carbon monoxide is preferably used for this, which is present at a medium or high pressure level, such as the turbine exhaust. Advantageously, the same phase separator is used for phase separation, in which the liquid carbon monoxide required for the cooling of the dephlegmator is deposited.

The invention further relates to a device for obtaining a gaseous carbon monoxide product by decomposing a feed gas consisting essentially of hydrogen (H ₂ ), carbon monoxide (CO) and methane (CH ₄ ), which in addition to a cryogenic methane scrubber (methane scrubbing) and lines for guiding the process streams at least a first heat exchanger for cooling and partial condensation of the feed gas and a regeneration device for the regeneration of laden methane detergent and a CO compressor for the compression of gaseous CO to product pressure (CO product compressor) comprises.

the device side the object is achieved in that the methane wash a with a refrigerant coolable second heat exchanger (dephlegmator) through which at least the gas phase of the partial Condensation of the feed gas generated biphasic mixture in countercurrent to liquid, flowing from top to bottom Methane (methane detergent) feasible is.

Of the Dephlegmator is preferred as a plate heat exchanger, as he is known in the art has been known for a long time. Draw such heat exchangers characterized by their compact design, as they in a small space a size area for the heat exchange included and so great specific services possible are.

Further developing the device according to the invention, it is proposed that the two-phase mixture produced in the partial condensation of the feed gas on one side of the dephlegmator can be fed while on the opposite side liquid methane can be introduced into the dephlegmator.

An embodiment of the device according to the invention comprises a phase separator, in which the two-phase mixture produced in the partial condensation of the feed gas in a H ₂ -rich, carbon monoxide-containing gas and CO-rich, hydrogen-containing liquid phase is separable, and from which the H ₂ -rich, carbon monoxide-containing gas phase of the dephlegmator is fed to the laundry. Advantageous variants provide that the phase separator is designed as an independent component or forms a structural unit in the form of an enlarged inlet header with the dephlegmator.

A Further embodiment of the device according to the invention provides a Device for providing liquid carbon monoxide for cooling the Dephlegmators, comprising means for returning a Part of the product purity having CO flow into the cryogenic gas separation unit, a heat exchanger, in which the recycled carbon monoxide is condensable, a throttle body through which the condensed carbon monoxide cold-performing is relaxing as well as a phase separator in which the case of the cold Relaxation generated phase mixture in a liquid and a gas phase separable is. Preferably, the means for returning from Product purity containing carbon monoxide in the cryogenic gas separation unit around the CO product compressor.

Another embodiment of the device according to the invention provides an H ₂ -Strippkolonne (H ₂ -Stripper) before, in the hydrogen-containing phases, in particular the laden methane detergent from the dephlegmator, can be introduced and in which they are liberated from hydrogen. A preferred variant of the device according to the invention provides that the H ₂ -tripper is not equipped with a reboiler, but with product purity exhibiting carbon dioxide is directly heated, which is introduced for this purpose in the bottom space of the H ₂ -Strippers.

A development of the device according to the invention provides for a CO / CH ₄ separation column, to which the bottom product consisting of methane and carbon monoxide can be fed from the H ₂ stripper for separation into carbon monoxide and methane.

Another variant of the device according to the invention provides a third heat exchanger in which process streams can be heated and cooled. These process streams are preferably at least part of the bottoms product from the H ₂ stripper which is heated, and carbon monoxide having CO ₂ -CH ₄ distillation column product purity and having product purity, recycled from the CO compressor both are cooled. A useful embodiment provides that a part of the second heat exchanger can be used as a reboiler for the CO / CH ₄ separation column.

Another variant of the device according to the invention provides an expansion turbine, the product purity exhibiting and preferably compressed in the CO compressor carbon monoxide (high-pressure CO) can be fed, which is advantageously cooled in the first heat exchanger and withdrawn through a side takeoff from this. From the outlet stream of the expansion turbine, a further CO flow can be removed at a medium pressure level, which is introduced, for example, as stripping gas into the sump space of an H ₂ stripper.

In the following, the invention with reference to two, in the 1 and 2 schematically illustrated embodiments will be explained in more detail. In the two figures, system components are marked with the same symbols.

The present embodiments relate to methods for decomposing a feed gas consisting essentially of hydrogen (H ₂ ), carbon monoxide (CO) and methane (CH ₄ ) 1 obtained by drying and the removal of carbon dioxide from a synthesis gas, wherein from the feed gas 1 Both a CO and a H ₂ product are generated.

The feed gas to be separated 1 is cooled in the heat exchanger E1 against process streams to be heated and thereby partially condensed. The emerging from the heat exchanger E1 two-phase flow 2 consisting of a H ₂ -rich, carbon monoxide and methane-containing gas phase and a CO-rich, hydrogen and methane-containing liquid phase, is in the lower part of the dephlegmator E4, which is designed as a plate heat exchanger and the function of the Methanwaschkolonne and the wash column cooler in a conventional methane wash takes over, abandoned. From the gas phase rising in the Dephlegmator E4, carbon monoxide and methane are mixed with liquid, supercooled methane detergent 64 washed out, which is supplied at the upper end of the dephlegmator E4. The gas emerging from the dephlegmator E4 stream 3 , which consists predominantly of hydrogen, and has a CO content of less than 0.5 mol% is warmed in E1, as raw hydrogen via line 4 to a pressure swing adsorption (not shown) continued and processed there to a H ₂ product. The heat that is selected in the solution of substances (mainly carbon monoxide) in the methane detergent 64 is released (solution heat), is dissipated by indirect heat exchange using carbon monoxide, the liquid via line 5 fed to the dephlegmator E4 and gaseous via line 6 is discharged again. By cooling thus carried out can with a lower compared to the prior art detergent quantity 64 be worked because the temperature of the methane detergent over the entire length of the dephlegmator remains approximately constant and therefore do not decrease the solubilities for the substances to be washed. The withdrawn at the bottom of the dephlegmator E4 liquid phase 10 , a mixture of methane, carbon monoxide and hydrogen, is split. A part 11 is relaxed via the throttle body a and as an intermediate feed 12 into the upper section of the H ₂ -stripping column (H ₂ -tripper) T2. The second partial flow 13 is also relaxed via the throttle body b, via line 14 passed into the heat exchanger E1, there partially evaporated and via line 15 the lower section of the H ₂ -Strippens T2 fed where it is used as an intermediate heating. In the H ₂ -tripper T2, the dissolved hydrogen from the CO / CH ₄ / H ₂ mixture 10 away. To the loss of CO over the H ₂ -rich head fraction 20 to minimize (<5 mol% CO), is used as reflux 65 for the H ₂ -tripper T2 supercooled liquid methane used.

The H ₂ -tripper T2, which is not equipped with a reboiler to reduce investment costs, is powered by a gaseous CO feed 97 heated, which is a partial flow 96 of the exhaust 92 the expansion turbine X1 acts, and its size is adjusted via the control valve h. This procedure allows a simple, independent control of the column, which is particularly advantageous for fast load changes. The efficiency loss through the direct feed can be minimized by the fact that for the CO feed 96 an optimum pressure level, which is only slightly above the operating pressure of the H ₂ -Strippes T2, is selected to keep the drive line for the CO compressor C1, C2 low.

The H ₂ -rich top fraction 20 from the H ₂ -tripper T2 is relaxed via the throttle body c, via line 21 Continue to run and with excess methane passing through the pipes 69 and 66 and the control valve j is withdrawn from the Methanwaschmittekreislauf mixed. The total current formed in this way 22 is evaporated in the main heat exchanger E1, warmed and as residual gas 23 issued.

The CH ₄ / CO mixture in the bottom of the H ₂ -stripper T2 is via line 30 deducted and split. The first partial flow 31 is relaxed via the throttle body d and via line 32 as an intermediate feed into the upper section of the CO / CH ₄ separation column T3. The second partial flow 33 is also relaxed via the throttle body e and via line 34 led into the heat exchanger E3, where it evaporates, via line 35 guided in the lower section of the CO / CH ₄ -treatment column T3 and used there as an intermediate heater. The CO / CH ₄ separation column T3 is fed through a reboiler, which is integrated into E3 and over the lines 36 and 37 is connected to the bottom space of the CO / CH ₄ separation column T3, heated. As a heating medium is high-pressure CO, via the line 90 led from the pressure side of the second section C2 of the CO compressor in the heat exchanger E1, cooled there and via line 97 is passed to the heat exchanger E3, where it is condensed and supercooled. The cooled carbon monoxide gets over line 98 deducted and into the two sub-streams 99 and 101 divided up. The partial flow 99 is relaxed via the throttle body f and via line 100 the CO / CH ₄ separation column T3 supplied as reflux, while the partial flow 101 via the throttle body g relaxed and thereby in a liquid-gas mixture 102 is reacted, which is then separated in the phase separator D2 in a liquid and a gas phase. The CO gas phase 7 from the phase separator D2 is the top product 40 the CO / CH ₄ separation column T3 admixed. A first part 5 the CO liquid phase from the phase separator D2 is fed to the dephlegmator E4 as refrigerant, while the remainder 8th the gaseous via line 41 in the heat exchanger E1 guided carbon monoxide is mixed to produce peak cold.

The predominantly methane bottoms product 60 from the CO / CH ₄ separation column T3 is supercooled in the heat exchanger E3, via line 61 withdrawn, brought under pressure by means of the pump P1, via line 62 fed to the heat exchanger E1 and there further supercooled against zuheizmende process streams. Via wire 63 the supercooled methane is passed on and into the two detergent streams 67 and 68 split, which are relaxed via the throttle bodies k and l. Not used as detergent methane 69 is after relaxation via the control valve j via line 66 continued and with the relaxed head fraction 21 of the H ₂ -stripper T2 to the material flow 22 mixed, which, after evaporation and heating in the heat exchanger E1, as residual gas 23 is passed on.

The one from the CO streams 41 and 8th formed CO stream is completely evaporated in the heat exchanger E1, warmed up and via line 42 supplied to the first section C1 of the CO compressor. The CO stream leaving the first section C1 of the CO compressor 44 comes with a CO stream 94 united, by warming up a part 93 of the exhaust 92 the expansion turbine X1 is generated in the heat exchanger E1. Part of the so formed CO stream is called CO product 43 continued while the remaining carbon monoxide 45 led into the second section C2 of the CO compressor, there compressed and via line 90 the heat exchanger E1 is supplied. In the heat exchanger E1, the CO flow 90 cooled and in the two CO streams 91 and 97 divided up. During the CO electricity 91 the expansion turbine X1 is supplied to generate cold, the CO flow 97 fed to the heat exchanger E3 and condensed there against process streams to be heated and supercooled.

The second, in 2 illustrated embodiment, differs from the first embodiment by the type of supply of the feed gas 2 to the Dephlegmator E4 and the use of the exhaust 92 the expansion turbine X1.

The emerging from the heat exchanger E1 two-phase flow 2 is fed to the phase separator D1 and into a H ₂ -rich, carbon monoxide and methane-containing gas phase 2a and a CO-rich, methane and hydrogen-containing liquid phase 13a separated. The dephlegmator E4 is only the gas phase 2a fed during the liquid phase 13a via the throttle body b 'relaxed and via line 14a is passed at the cold end in the heat exchanger E1.

A part 50 of the turbine exhaust 92 is condensed in the heat exchanger E1 and undercooled, relaxed via the throttle body i and via line 51 passed into the phase separator D2, creating more liquid CO 8th is available as peak cold for the cold end of E1. This process variant is especially advantageous when the H ₂ / CO ratio in the feed gas 1 high and / or the pressure of the feed gas 1 is low.

Claims (9)

A process for obtaining a carbon monoxide product from a feed gas consisting essentially of hydrogen (H ₂ ), carbon monoxide (CO) and methane (CH ₄ ), wherein a biphasic substance mixture consisting of an H ₂ -oxide is produced from the feed gas by cooling against process streams to be heated. rich, carbon monoxide and methane-containing gas phase and a CO-rich, hydrogen and methane-containing liquid phase, and wherein subsequently at least the H ₂ -rich, carbon monoxide and methane-containing gas phase is subjected to a cryogenic scrubbing with liquid methane (methane scrubbing), characterized that the methane wash is carried out in a second heat exchanger (dephlegmator), for which the gas phase of the biphasic mixture in countercurrent to liquid, supercooled methane (methane detergent) is guided from bottom to top through the dephlegmator and in the solution of gaseous effluents in the methane detergent released heat (solution heat) is absorbed in the indirect heat exchange of a, preferably in countercurrent to the methane scrubbing medium by the dephlegmator guided refrigerant. Method according to claim 1, characterized in that that the gas phase of the generated during the cooling of the feed gas two-phase mixture together with the liquid phase in the dephlegmator initiated and separated within the dephlegmator becomes. Method according to claim 1, characterized in that that during cooling of the feed gas produced biphasic mixture in one of the Methanwäsche upstream Separation step separated into a gas and a liquid phase and only the Gas phase for leaching at least carbon monoxide into the dephlegmator is initiated. Method according to one of claims 1 to 3, characterized that as a refrigerant for the dephlegmator liquid Carbon monoxide is used. Method according to claim 4, characterized in that that product quality condensed carbon monoxide, then cooled against heated process streams cooled, thereby liquefied and following a cold-drinking Relaxation by means of a phase separator in a gas and a liquid phase is separated, wherein at least a portion of the thus obtained liquid phase as a refrigerant fed to the dephlegmator becomes. Apparatus for obtaining a gaseous carbon monoxide product by decomposing a feed gas consisting essentially of hydrogen (H ₂ ), carbon monoxide (CO) and methane (CH ₄ ), which in addition to a cryogenic methane scrubber (methane scrubbing) and lines for guiding the process streams at least a first heat exchanger for Cooling and partial condensation of the feed gas and a regeneration device for the regeneration of laden methane detergent and a CO compressor for compressing gaseous CO to product pressure (CO product compressor), characterized in that the methane wash has a second heat exchanger (dephlegmator) which can be cooled with a refrigerant , through which at least the gas phase of the two-phase mixture produced in the partial condensation of the feed gas in countercurrent to liquid, from top to bottom flowing methane (methane detergent) is feasible. Apparatus according to claim 6, characterized in that the dephlegmator as plates heat exchanger is executed. Device according to one of claims 6 to 7, characterized in that in front of the dephlegmator, a phase separator is arranged, in which the biphasic mixture produced in the partial condensation of the feed gas in an H ₂ -rich, carbon monoxide-containing gas and a CO-rich, Hydrogen-containing liquid phase is separable, and from which the H ₂ -rich, carbon monoxide-containing gas phase is fed to the dephlegmator. Device according to one of claims 6 to 8, characterized a device for providing liquid carbon monoxide for cooling the Dephlegmators is provided, comprising a CO compressor for Compression and recirculation of a Part of the product quality having CO stream into the cryogenic gas separation unit, a Heat exchanger, in which the recycled carbon monoxide is condensable, a throttle body, via which the condensed carbon monoxide cold is relaxing as well as a phase separator in which the case of the cold Relaxation generated phase mixture in a liquid and a gas phase separable is.