Hydrogen gas production device and hydrogen gas production method

A hydrogen gas producing apparatus, comprising:

• a porous body that (i) is formed of a ceramic and (ii) has a cumulative pore diameter distribution in which a pore diameter (D80) at a number cumulative frequency of 80% is 800 nm or less, thereby causing the porous body to be permeable to hydrogen gas and to carbon dioxide gas and to have a property of being more permeable to the hydrogen gas than to the carbon dioxide gas;
• a gas flow channel that includes a flow inlet at one end thereof and a flow outlet at another end thereof, the porous body being disposed inside the gas flow channel;
• and
• a mixed gas source that causes a mixed gas to flow into the porous body through the flow inlet, the mixed gas including the carbon dioxide gas and the hydrogen gas;
• and
• a heater to heat at least one of the porous body or the mixed gas,
• wherein
• a pressure gradient represented by (P1− P2)/L is less than 50 M Pa/m where L represents a length of the porous body in a direction in which the mixed gas permeates, P1 represents an inflow pressure of the mixed gas into the porous body, and P2 represents an outflow pressure from the porous body,
• the mixed gas is flowed into the porous body under a temperature environment heated to 200° C. or higher by the heater.

A hydrogen gas producing method comprising:

• preparing a mixed gas that includes carbon dioxide gas and hydrogen gas and has a carbon dioxide gas concentration of 50% by mole or less;
• and
• causing, under a temperature environment at room temperature, the mixed gas to flow into a porous body that (i) is formed of a ceramic and (ii) is permeable to the hydrogen gas and to the carbon dioxide gas
• wherein
• the porous body has a cumulative pore diameter distribution in which a pore diameter (D80) at a number cumulative frequency of 80% is 800 nm or less, thereby causing the porous body to have a property of being more permeable to the hydrogen gas than to the carbon dioxide gas,
• a pressure gradient represented by (P1− P2)/L is 10 MPa/m or less where L represents a length of the porous body in a direction in which the mixed gas permeates, P1 represents an inflow pressure of the mixed gas into the porous body, and P2 represents an outflow pressure from the porous body.

A hydrogen gas producing method comprising:

• preparing a mixed gas including carbon dioxide gas and hydrogen gas;
• and
• causing, under a temperature environment at 200° C. or higher, the mixed gas to flow into a porous body that (i) is formed of a ceramic and (ii) is permeable to the hydrogen gas and to the carbon dioxide gas,
• wherein
• the porous body has a cumulative pore diameter distribution in which a pore diameter (D80) at a number cumulative frequency of 80% is 800 nm or less, thereby causing the porous body to have a property of being more permeable to the hydrogen gas than to the carbon dioxide gas,
• a pressure gradient represented by (P1− P2)/L is less than 50 MPa/m where L represents a length of the porous body in a direction in which the mixed gas permeates, P1 represents an inflow pressure of the mixed gas into the porous body, and P2 represents an outflow pressure from the porous body.