Process for producing a product gas containing carbon oxides and hydrogen from methanol

Claim 2

A process for producing a product gas containing carbon oxides and hydrogen which comprises the steps of: (a) mixing methanol vapor with a gas mixture consisting at least predominantly of carbon dioxide and hydrogen to form a high-methanol mixed feedstock; (b) feeding said mixed feedstock with an entrance temperature of 300° to 400° C. to a first catalytic reaction zone operated with a zinc-containing catalyst at a temperature up to about 600° and a pressure of 10 to 50 bars to produce an intermediate having a methanol content not exceeding 1% by volume; (c) withdrawing said intermediate from said first catalytic reaction zone, (c 1 ) cooling said intermediate to condense water therein, (c 2 ) removing at least part of the condensed water from the intermediate, and (c 3 ) reheating the cooled intermediate from which condensed water has been removed to a temperature of about 320° C. to 420° C., (d) supplying at least 30% of the reheated intermediate to a second catalytic reaction zone operated with a zinc-containing catalyst at a temperature up to about 600° C. and a pressure of 10 to 50 bars to produce a precursor product at a temperature of about 350° C. to 600° C.; (e) withdrawing said precursor product from said second catalytic reaction zone, (e 1 ) cooling the withdrawn precursor product, and (e 2 ) removing an aqueous condensate from the cooled precursor product; (f) separating the precursor product from which said aqueous condensate has been removed into at least two gas streams by passing the precursor product through a plurality of selectively permeable membranes in a separating zone; (g) withdrawing a first gas stream containing at least 90% by volume hydrogen and carbon dioxide from said separating zone, (g 1 ) mixing additional carbon dioxide with the withdrawn first gas stream, and (g 2 ) feeding the first gas stream with which additional carbon dioxide has been mixed to step (a) and said gas mixture thereof; and (h) withdrawing as a second gas stream from said separating zone a product stream containing at least 30% by volume carbon monoxide.

Claim 3

The process defined in claim 1 wherein at least 50% of the reheated intermediate from step (c 3 ) is supplied in step (d) to said second catalytic reaction zone.

Claim 4

The process defined in claim 2 wherein said high-methanol mixed feedstock contains 15 to 75% by volume hydrogen.

Claim 5

The process defined in claim 2 wherein said high-methanol mixed feedstock contains 10 to 75% by volume carbon dioxide.

Claim 6

The process defined in claim 2 wherein said intermediate supplied to said second catalytic reaction zone contains at most 2% by volume water vapor.

Claim 7

The process defined in claim 2, further comprising the step of: (i) removing at least part of the CO 2 contained in the second gas stream therefrom in forming said product stream.

Claim 8

The process defined in claim 6, further comprising the step of: (j) feeding the CO 2 removed in step (i) to the first gas stream of step (g 2 ) as said additional carbon dioxide.

Claim 9

A process for producing a product gas containing carbon oxides and hydrogen which comprises the steps of: (a) mixing methanol vapor with a gas mixture consisting at least predominantly of carbon dioxide and hydrogen to form a high-methanol mixed feedstock; (b) feeding said mixed feedstock with an entrance temperature of 300° to 400° C. to a first catalytic reaction zone operated with a zinc-containing catalyst at a temperature up to about 600° C. and a pressure of 10 to 50 bars to produce an intermediate having a methanol conttent not exceeding 1% by volume; (c) withdrawing said intermediate from said first catalytic reaction zone, (c 1 ) cooling said intermediate to condense water therein, (c 2 ) removing at least part of the condensed water from the intermediate, and (c 3 ) reheating the cooled intermediate from which condensed water has been removed to a temperature of about 320° C. to 420° C.; (d) recycling a partial stream consisting of 40 to 70% of said intermediate from which condensed water has been removed to step (a) for admixture with methanol vapor in the formation of said high-methanol feedstock; (e) supplying the remainder of the reheated intermediate to a second catalytic reaction zone operated with a zinc-containing catalyst at a temperature up to about 600° C. and a pressure of 10 to 50 bars to produce a precursor product at a temperature of about 350° C. to 600° C.; (f) withdrawing said precursor product from said second catalytic reaction zone, (f 1 ) cooling the withdrawn precursor product, and (f 2 ) removing an aqueous condensate from the cooled precursor product; (g) separating the precursor product from which said aqueous condensate has been removed into at least two gas streams by passing the precursor product through a plurality of selectively permeable membranes in a separating zone; (h) withdrawing a first gas stream containing at least 90% by volume hydrogen and carbon dioxide from said separating zone, (h 1 ) mixing additional carbon dioxide with the withdrawn first gas stream, and (h 2 ) feeding the first gas stream with which additional carbon dioxide has been mixed to step (a) and said gas mixture thereof; and (i) withdrawing as a second gas stream from said separating zone a product stream containing at least 30% by volume carbon monoxide.

Claim 10

A process for producing a product gas containing carbon oxides and hydrogen which comprises the steps of: (a) mixing methanol vapor with a gas mixture consisting at least predominantly of carbon dioxide and hydrogen to form a high-methanol mixed feedstock; (b) feeding said mixed feedstock with an entrance temperature of 300° to 400° C. to a first catalytic reaction zone operated with a zinc-containing catalyst at a temperature up to about 600° C. and a pressure of 10 to 50 bars to produce an intermediate having a methanol conttent not exceeding 1% by volume; (c) withdrawing said intermediate from said first catalytic reaction zone, (c 1 ) cooling said intermediate to condense water therein, (c 2 ) removing at least part of the condensed water from the intermediate, and (c 3 ) reheating the cooled intermediate from which condensed water has been removed to a temperature of about 320° C. to 420° C.; (d) recycling a partial stream consisting of 40 to 70% of said intermediate from which condensed water has been removed to step (a) for admixture with methanol vapor in the formation of said high-methanol feedstock; (e) supplying the remainder of the reheated intermediate to a second catalytic reaction zone operated with a zinc-containing catalyst at a temperature up to about 600° C. and a pressure of 10 to 50 bars to produce a precursor product at a temperature of about 350° C. to 600° C.; (f) withdrawing said precursor product from said second catalytic reaction zone, (f 1 ) cooling the withdrawn precursor product, and (f 2 ) removing an aqueous condensate from the cooled precursor product; (g) separating the precursor product from which said aqueous condensate has been removed into at least two gas streams by passing the precursor product through a plurality of selectively permeable membranes in a separating zone; (h) withdrawing a first gas stream containing at least 90% by volume hydrogen and carbon dioxide from said separating zone, (h 1 ) mixing additional carbon dioxide with the withdrawn first gas stream, and (h 2 ) feeding the first gas stream with which additional carbon dioxide has been mixed to step (a) and said gas mixture thereof; and (i) withdrawing as a second gas stream from said separating zone a product stream containing at least 30% by volume carbon monoxide.

Claim 11

The process defined in claim 8 wherein at least 50% of the reheated intermediate from step (c 3 ) is supplied in step (d) to said second catalytic reaction zone.

Claim 12

The process defined in claim 8 wherein said high-methanol mixed feedstock contains 15 to 75% by volume hydrogen.

Claim 13

The process defined in claim 8 wherein said high-methanol mixed feedstock contains 10 to 75% by volume carbon dioxide.

Claim 14

The process defined in claim 8 wherein said intermediate supplied to said second catalytic reaction zone contains at most 2% by volume water vapor.

Claim 15

The process defined in claim 8, further comprising the step of: (i) removing at least part of the CO 2 contained in the second gas stream therefore in forming said product stream.

Claim 16

The process defined in claim 13, further comprising the step of: (j) feeding the CO 2 as said additional carbon dioxide.