Promoted mixed oxides for “low-temperature” methane partial oxidation in absence of gaseous oxidants
AssigneeNorth Carolina State University
InventorsFanxing Li, Arya Shafiefarhood, Amit Mishra
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Abstract
Redox catalysts are provided for “low-temperature” methane partial oxidation in absence of gaseous oxidants. Methods of converting the methane to syngas using the catalysts are also provided. In some aspects, the conversion takes place at temperatures of about 400° C. to about 950° C. The methods can be used to convert methane to syngas containing carbon monoxide and hydrogen gas. In some aspects, the methods are carried out in a fixed bed reactor with reverse flow.
Claims26
A method of converting methane to syngas, the method comprising contacting the methane with a redox catalyst to produce the syngas,
- wherein the redox catalyst comprises metal cations and is (1) a cerium containing oxide or (2) a perovskite oxide comprising La, Ba, Sr, Ca, or any combination thereof;
- wherein the redox catalyst is in a fixed bed reactor having a first end and a second end;
- wherein the redox catalyst nearest the first end is initially at a first high average oxidation state and the redox catalyst nearest the second end is initially at a second low average oxidation state lower than the first high average oxidation state, and
- wherein the method comprises:
- (1) introducing the methane into the fixed bed reactor near the first end for a first period of time;
- wherein the methane contacts the redox catalyst in the first high average oxidation state near the first end of the fixed bed reactor;
- and
- wherein after the first period of time the redox catalyst nearest the first end is in a third low average oxidation state;
- (2) introducing a first amount of an oxidant into the fixed bed reactor near the second end for a second period of time;
- and
- wherein after the second period of time the redox catalyst near the second end is in a fourth high average oxidation state higher than the third low average oxidation state;
- (3) introducing the methane into the fixed bed reactor near the second end for a third period of time;
- wherein the methane contacts the redox catalyst in the fourth high average oxidation state near the second end of the fixed bed reactor;
- and
- wherein after the third period of time the redox catalyst nearest the second end is in a fifth low average oxidation state;
- and
- (4) introducing a second amount of the oxidant into the fixed bed reactor near the first end for a fourth period of time;
- and
- wherein after the fourth period of time the redox catalyst near the first end is in a sixth high average oxidation state higher than the fifth low average oxidation state.
Dependencies are inferred from the claim text.