Patent ID: 11964265
Assignee: TOYOTA JIDOSHA KABUSHIKI KAISHA
Field: Chemical engineering (Chemistry)
Classification: CPC B  C | IPC B  C

Claim 0:
1. A methane producing method comprising:
oxidizing nickel through a heat treatment of a methanation catalyst by supplying an oxygen gas containing oxygen and nitrogen to a reactor, the reactor housing the methanation catalyst containing the nickel as a catalyst component;
stopping the supply of the oxygen gas to the reactor, thereby ending the oxidizing and stopping the operation of the reactor; and
generating methane by supplying a raw material gas containing carbon dioxide and hydrogen to the reactor housing the methanation catalyst in which the nickel has been oxidized in the oxidizing after the stopping of the operation of the reactor,
wherein in the oxidizing, the oxygen gas is supplied to the reactor such that the oxygen is supplied to 1 g of the methanation catalyst at a supply rate in a range of from 0.0213 mmol-O2/sec·g-cat. to 0.0638 mmol-O2/sec·g-cat., and a time period of the heat treatment of the methanation catalyst by supplying the oxygen gas to the reactor is set to 30 minutes or more,
wherein in the oxidizing, an oxygen concentration of the oxygen gas is in a range of from 1 volume % to 3 volume %, and a temperature of the oxygen gas at a gas inlet of the reactor is in a range of from 60° C. to 150° C., and
wherein when a temperature ° C. of the oxygen gas at the gas inlet of the reactor in the oxidizing is X1, an oxygen concentration volume % of the oxygen gas in the oxidizing is X2, and a temperature ° C. of the raw material gas at the gas inlet of the reactor when a conversion rate of the carbon dioxide in the generating is 50% is Y, formulae (1) to (4) below are satisfied

Y=153.091+0.487X1+17.714X2  (1)

160≤Y<250  (2)

0<X1  (3)

0<X2  (4).