Gas separation apparatus, membrane reactor, and hydrogen production apparatus

A membrane reactor that carries out a CO shift treatment on a gas to be shifted containing carbon monoxide and water vapor, comprising:

• a first treatment section having a first separation membrane formed on at least a part of an outer circumferential surface of an occupied space thereof, an inside of the first treatment section being filled with a CO shift catalyst, the first separation membrane having a CO2/H2 selective separation performance;
• and
• a second treatment section having a second separation membrane formed on at least a part of an outer circumferential surface of an occupied space thereof, the second separation membrane having a H2O/CO2 selective separation performance and being made of a material different from that of the first separation membrane, wherein
• the first treatment section produces a first mixture gas containing hydrogen, carbon dioxide, and water vapor by performing a shift treatment on the gas to be shifted with use of the CO shift catalyst under a temperature condition of 100° C. or higher, and allows carbon dioxide and water vapor contained in the first mixture gas to permeate through the first separation membrane selectively over hydrogen, and
• the second treatment section receives supply of a second mixture gas containing carbon dioxide and water vapor that have permeated through the first separation membrane, and allows water vapor contained in the second mixture gas to permeate through the second separation membrane selectively over carbon dioxide.

A hydrogen production method comprising:

• a reforming step of receiving supply of a gas to be reformed containing hydrocarbon and water vapor and producing a gas to be shifted containing carbon monoxide, hydrogen, and water vapor by performing a reforming treatment on the gas to be reformed with use of a reforming catalyst;
• a shifting step of receiving supply of the gas to be shifted and producing a first mixture gas containing hydrogen, carbon dioxide, and water vapor by performing a CO shift treatment on the gas to be shifted with use of a shift catalyst under a temperature condition of 100° C. or higher;
• a first separation step of supplying the first mixture gas to be brought into contact with a surface of a first separation membrane having a CO2/H2 selective separation performance so as to separate a second mixture gas containing carbon dioxide and water vapor that permeate through the first separation membrane from the first mixture gas by allowing carbon dioxide and water vapor contained in the first mixture gas to permeate through the first separation membrane selectively over hydrogen and to recover an object gas containing hydrogen that does not permeate through the first separation membrane as a major component;
• and
• a second separation step of supplying the second mixture gas to be brought into contact with a surface of a second separation membrane having a H2O/CO2 selective separation performance and made of a material different from that of the first separation membrane so as to separate water vapor that permeates through the second separation membrane from the second mixture gas by allowing water vapor contained in the second mixture gas to permeate through the second separation membrane selectively over carbon dioxide, wherein
• the shifting step and the first separation step are carried out in parallel within an identical treatment mechanism, and
• at least part of water vapor recovered in the second separation step is utilized for reaction in the shifting step.