Methods of selectively separating CO2 from a multicomponent gaseous stream using CO2 hydrate promoters

A method for removing CO2 from a multicomponent gaseous stream to produce a CO2 depleted gaseous stream, said method comprising:

• (a) providing a multicomponent gaseous stream;
• (b) contacting said multicomponent gaseous stream with CO2 nucleated water under conditions sufficient to produce CO2 hydrates, whereby CO2 is removed from said gaseous stream and concomitantly fixed as CO2 clathrates upon said contacting to produce a CO2 depleted gaseous stream and a CO2 clathrate slurry;
• and
• (c) separating said CO2 depleted gaseous stream from said CO2 clathrate slurry;
• with the proviso that said method further comprises reducing the CO2 partial pressure requirement of hydrate formation as compared to a control by providing a sufficient amount of a CO2 hydrate promoter in at least one of said gaseous stream and said nucleated water, wherein said CO2 hydrate promoter is present in an amount sufficient to reduce the CO2 partial pressure requirement of hydrate formation at 0° C. as compared to a control;
• whereby CO2 is removed from a multicomponent gaseous stream.

A method for removing CO2 from a multicomponent gaseous stream to produce a CO2 depleted gaseous stream, said method comprising:

• (a) providing a multicomponent gaseous stream comprising a gaseous CO2 hydrate promoter that reduces the CO2 partial pressure requirement of hydrate formation as compared to a control, wherein said gaseous CO2 hydrate promoter is a compound that has a vapor pressure ranging from about 0.1 to 1 atm at its hydrate formation temperature, wherein said CO2 hydrate promoter is present in an amount sufficient to provide for CO2 hydrate formation at a CO2 partial pressure of less than about 9 atm at about 0° C.;
• (b) contacting said multicomponent gaseous stream with CO2 nucleated water under conditions sufficient to produce CO2 hydrates, whereby CO2 is removed from said gaseous stream and concomitantly fixed as CO2 clathrates upon said contacting to produce a CO2 depleted gaseous stream and a CO2 clathrate slurry, wherein said CO2 nucleated water optionally contains a CO2 hydrate promoter;
• and
• (c) separating said CO2 depleted gaseous stream from said CO2 clathrate slurry;
• whereby CO2 is removed from a multicomponent gaseous stream.