Patent ID: 8557024

Claim:
A method of removing hydrogen sulfide from shifted syngas, comprising: dehydrating and cooling the shifted syngas in an amount sufficient to convert the hydrogen sulfide in the shifted syngas to carbonyl sulfide; absorbing the carbonyl sulfide from the shifted syngas in an absorber using liquid carbon dioxide to produce a desulfurized syngas and a carbonyl sulfide containing liquid carbon dioxide product; feeding the desulfurized syngas into an autorefrigeration unit to form the liquid carbon dioxide from the desulfurized syngas and to further produce a desulfurized and decarbonized syngas; using refrigeration content in the desulfurized and decarbonized syngas and the carbonyl. sulfide containing liquid carbon dioxide product in the step of cooling the shifted syngas; and feeding the desulfurized and decarbonized syngas into a hydrogen pressure swing absorption (PSA) unit to produce a hydrogen product and a carbon dioxide-containing PSA offgas.