Method for upgrading a gas
The invention relates to a method for upgrading a gas by separation of carbon dioxide therefrom, which method comprises the steps of introducing a stream of gas to a wet bed of ion exchange resin, and desorbing the adsorbed carbon dioxide from the resin by increasing the temperature and/or lowering the pressure in said wet bed.
1. A method for upgrading or cleaning a gas by separation of carbon dioxide therefrom, comprising the steps of
introducing a stream of said gas into a bed of a weakly basic ion exchange resin provided with tertiary amine groups, at temperature and pressure conditions, under which the carbon dioxide is adsorbed to said resin, and
desorbing the adsorbed carbon dioxide from the resin by increasing the temperature and/or lowering the pressure in said bed,
wherein the content of water in said bed of ion exchange resin during step i) amounts to more than 35% of the total weight of ion exchange resin and water.
2. The method according to claim 1 , wherein the gas is flue gas, which is cleaned.
3. The method according to claim 1 , wherein the gas is upgraded by separation of carbon dioxide from methane.
4. The method according to claim 3 , wherein the gas is biogas.
5. The method according to claim 1 , wherein the content of water in said bed of ion exchange resin during step i) amounts to 50% or more of the total weight of ion exchange resin and water.
6. The method according to claim 1 , wherein the content of water in said bed of ion exchange resin during step i) amounts to less than 70% of the total weight of ion exchange resin and water.
7. The method according to claim 1 , wherein during step i) a flow of water counter to the stream of gas is provided for.
8. The method according to claim 1 , wherein the temperature of the bed of ion exchange resin is increased in step ii) by injecting warm water directly into said bed.
9. The method according to claim 1 , wherein the temperature of the bed of ion exchange resin is lowered prior to step i) by injecting cold water directly into said bed.
10. The method according to claim 1 , wherein cooling and heating of the bed of ion exchange resin is assisted by one or more heat exchangers in the form of a mantle encircling the bed of ion exchange resin or elements protruding into said bed.
11. The method according to claim 1 , wherein step i) is performed at a pressure of 2 bars or more.
12. The method according to claim 1 , wherein step i) is performed at a pressure of 10 bars or more.
13. The method according to claim 1 , wherein step i) is performed at a pressure of 16 bars.