Methanol synthesis process

Claim 2

A process of treating hydrocarbons which comprises: (a) reacting a normally gaseous hydrocarbon with steam endothermically over a catalyst at an outlet temperature in the range 700° to 900° C. in a reaction zone heated by a combustion furnace, to give a process gas stream containing hydrogen, carbon monoxide and carbon dioxide; (b) cooling the process gas stream of step (a), separating the condensed water and passing the resulting process gas stream over a copper-containing methanol synthesis catalyst to give a reacted synthesis gas containing methanol at a temperature in the range 160° to 300° C.; (c) transferring heat contained in said reacted synthesis gas at 160° to 300° C. by indirect heat exchange to liquid water under pressure; and (d) bringing the resulting hot liquid water under pressure into direct heat exchange with the normally gaseous hydrocarbon to be reacted in step (a), to provide 10% to 30% of the steam to be reacted in step (a).

Claim 3

A process according to claim 1 including the step of recovering heat by cooling the combustion gases discharged from said furnace in heat exchange in a boiler raising steam at a pressure 60 to 120 ata.

Claim 4

A process according to claim 1 including the step of recovering heat by cooling said process gas stream in heat exchange in a boiler raising steam at a pressure in the range 60 to 120 ata.

Claim 5

A process according to claim 1 in which the reacted synthesis gas at a temperature in the range 160° to 300° C. is divided into two part-streams, one of which is heat-exchanged with synthesis gas to bring it to synthesis inlet temperature and the other of which is heat-exchanged with the liquid water under pressure.

Claim 6

A process according to claim 1 in which step (a) is operated at a pressure over 10 ata.

Claim 7

A methanol production process which comprises: (a) generating methanol synthesis gas by reacting a normally gaseous hydrocarbon with steam endothermically over a catalyst at an outlet temperature in the range 700° to 900° C. in a reaction zone heated by a combustion furnace, to give a process gas stream containing hydrogen, carbon monoxide and carbon dioxide; (b) generating steam at a pressure of at least 50 ata by cooling said process gas stream in heat exchange in a boiler, separating the condensed water and bringing synthesis gas to synthesis pressure by means of a compressor driven by an engine in which said steam is let down; (c) passing the resulting process gas stream over a copper-containing methanol synthesis catalyst to give a reacted synthesis gas containing methanol at a temperature in the range 160° to 300° C.; (d) dividing the reacted synthesis gas of step (c) into two part-streams, one of which is heat-exchanged with synthesis gas to bring it to synthesis inlet temperature and the other of which is heat-exchanged with liquid water maintained under a pressure too high to permit boiling to take place; and (e) recovering methanol from the cooled methanol-containing synthesis gas from stage (d), wherein: (i) the hot water from stage (d) under pressure is brought into direct heat exchange with the normally gaseous hydrocarbon to be reacted in step (a), to provide 10% to 30% of the steam to be reacted in step (a); and (ii) exhaust steam rom the letdown engine of step (b) is supplied to the steam reforming of step (a).

Claim 8

A methanol production process which comprises: (a) generating methanol synthesis gas by reacting a normally gaseous hydrocarbon with steam endothermically over a catalyst at an outlet temperature in the range 700° to 900° C. in a reaction zone heated by a combustion furnace, to give a process gas stream containing hydrogen, carbon monoxide and carbon dioxide; (b) generating steam at a pressure of at least 50 ata by cooling said process gas stream in heat exchange in a boiler, separating the condensed water and bringing synthesis gas to synthesis pressure by means of a compressor driven by an engine in which said steam is let down; (c) passing the resulting process gas stream over a copper-containing methanol synthesis catalyst to give a reacted synthesis gas containing methanol at a temperature in the range 160° to 300° C.; (d) dividing the reacted synthesis gas of step (c) into two part-streams, one of which is heat-exchanged with synthesis gas to bring it to synthesis inlet temperature and the other of which is heat-exchanged with liquid water maintained under a pressure too high to permit boiling to take place; and (e) recovering methanol from the cooled methanol-containing synthesis gas from stage (d), wherein: (i) the hot water from stage (d) under pressure is brought into direct heat exchange with the normally gaseous hydrocarbon to be reacted in step (a), to provide 10% to 30% of the steam to be reacted in step (a); and (ii) exhaust steam rom the letdown engine of step (b) is supplied to the steam reforming of step (a).