Desulfurization of carbon dioxide-containing gases

A method for desulfurization of crude carbon dioxide (CO2) gas comprising hydrogen sulfide (H2S) and optionally at least one other sulfur-containing impurity comprising:

• feeding crude CO2 gas comprising H2S to a Claus process to convert H2S in the presence of oxygen (O2) gas to elemental sulfur and produce Claus tail-gas comprising CO2, residual H2S and at least one other sulfur-containing impurity;
• feeding said Claus tail-gas to a hydrogenation process to convert said at least one other sulfur-containing impurity into H2S in the presence of hydrogen (H2) and produce H2S-enriched CO2 tail-gas;
• cooling said H2S-enriched CO2 tail gas and removing condensed water to produce cooled H2S-enriched CO2 tail gas;
• compressing said cooled H2S-enriched CO2 tail-gas, or an impure CO2 gas comprising H2S derived therefrom, to produce compressed impure CO2 gas comprising H2S;
• removing H2S and any other sulfur-containing impurities from said compressed impure CO2 gas by physical separation or by chemical reaction with at least one solid metal oxide to form at least one solid metal sulfide and subsequent oxidative regeneration, to produce purified CO2 and a first recycle gas comprising at least one sulfur-containing compound;
• and
• recycling said first recycle gas to said Claus process to convert said at least one sulfur-containing compound into elemental sulfur;
• recovering H2S from said H2S-enriched CO2 tail-gas by selective amine absorption to produce H2S-depleted CO2 tail-gas and recovered H2S;
• recycling said recovered H2S to said Claus process to convert said recovered H2S to elemental sulfur;
• and
• recovering CO2 and residual H2S from said H2S-depleted CO2 tail-gas by non-selective amine absorption to produce said impure CO2 gas for compression, together with waste gas comprising CO2 and at least one non-condensable gas,
• wherein said H2S-depleted CO2 tail-gas is compressed directly to produce said compressed impure CO2 gas.

A method for desulfurization of crude carbon dioxide (CO2) gas comprising hydrogen sulfide (H2S) and optionally at least one other sulfur-containing impurity comprising:

• feeding crude CO2 gas comprising H2S to a Claus process to convert H2S in the presence of oxygen (O2) gas to elemental sulfur and produce Claus tail-gas comprising CO2, residual H2S and at least one other sulfur-containing impurity;
• feeding said Claus tail-gas to a hydrogenation process to convert said at least one other sulfur-containing impurity into H2S in the presence of hydrogen (H2) and produce H2S-enriched CO2 tail-gas;
• cooling said H2S-enriched CO2 tail gas and removing condensed water to produce cooled H2S-enriched CO2 tail gas;
• compressing said cooled H2S-enriched CO2 tail-gas, or an impure CO2 gas comprising H2S derived therefrom, to produce compressed impure CO2 gas comprising H2S;
• removing H2S and any other sulfur-containing impurities from said compressed impure CO2 gas by physical separation or by chemical reaction with at least one solid metal oxide to form at least one solid metal sulfide and subsequent oxidative regeneration, to produce purified CO2 and a first recycle gas comprising at least one sulfur-containing compound;
• and
• recycling said first recycle gas to said Claus process to convert said at least one sulfur-containing compound into elemental sulfur;
• wherein H2S and any other sulfur-containing impurities are removed from said compressed impure CO2 gas by selective adsorption as said physical separation,
• wherein said selective adsorption involves removing H2S and any other sulfur-containing compounds in the compressed impure CO2 gas by adsorption on a bed comprising at least one adsorbent material selective for sulfur-containing compound(s) in a selective adsorption unit to produce said purified CO2 and, after desorption with a regeneration gas, a spent regeneration gas comprising said H2S and any other sulfur-containing compounds from the compressed impure CO2 gas as said first recycle gas.