Method and a system for abating H
A method and a system for abating hydrogen sulfide (H 2 S) and carbon dioxide (CO 2 ) from H 2 S and CO 2 rich gas mixtures such as geothermal non-condensable gas mixtures (NCG). The H 2 S and CO 2 gas is separated from the remaining gases contained in the H 2 S and CO 2 rich gas mixtures by pressurizing the gas stream and feeding it into an absorption column where H 2 S and CO 2 are preferentially dissolved in a water stream, resulting in water stream rich in H 2 S and CO 2 . The H 2 S and CO 2 rich water stream may then be re-injected into a geological reservoir or used for pH modification of another water stream of geological origin.
1. A method for abating at least part of hydrogen sulfide (H 2 S) and at least 50% of carbon dioxide (CO 2 ) present in a Non-Condensable gas (NCG) mixture (G1), encompassing H 2 S and CO 2 and at least also one of H 2 , N 2 , CH 4 and/or Ar, comprising the steps of:
pressurizing said NCG mixture (G1), encompassing H 2 S and CO 2 and at least also one of H 2 , N 2 , CH 4 and/or Ar, to a pressure between 6 and 20 bar, and
contacting a stream of said pressurized NCG mixture (G1), encompassing H 2 S and CO 2 and at least also one of H 2 , N 2 , CH 4 and/or Ar, with a stream of water (W2) having a pressure between 6 and 23 bar, wherein a flow ratio, as measured in kg/s, of the stream of water (W2) to the stream of gas mixture (G1) is from 36:1.5 to 56:0.2,
absorption of at least part of said H 2 S and at least 50% of said CO 2 from said pressurized NCG mixture (G1), encompassing H 2 S and CO 2 and at least also one of H 2 , N 2 , CH 4 and/or Ar, into said water stream (W2), thereby
separating said at least part of said H 2 S and at least 50% of said CO 2 from at least part of said at least also one of H 2 , N 2 , CH 4 and/or Ar and producing a stream of water (W4) enriched with dissolved H 2 S and CO 2 comparable to said water stream (W2) and a stream of pressurized gas (G3), which has been depleted of at least part of the H 2 S and at least 50% of the CO 2 compared to said NCG mixture (G1), encompassing H 2 S and CO 2 and at least also one of H 2 , N 2 , CH 4 and/or Ar,
transferring said water stream (W4) enriched with dissolved H 2 S and CO 2 :
either to an injection well for injecting said water stream (W4) into a geological reservoir, or
to a system for injection of a water stream (W5) into a geological reservoir for use of said water stream (W4) as an aid for pH-regulation of said water stream (W5).
2. The method according to claim 1 , wherein the pressure of said pressurized NCG mixture (G1), encompassing H 2 S and CO 2 and at least also one of H 2 , N 2 , CH 4 and/or Ar, is between 6 and 12 bar.
3. The method according to claim 1 , wherein said NCG mixture (G1), encompassing H 2 S and CO 2 and at least also one of H 2 , N 2 , CH 4 and/or Ar, has a temperature of between 30 and 60° C.
4. The method according to claim 1 , wherein said water stream (W2) has a temperature of between 4 and 40° C.
5. The method according to claim 1 , wherein the flow of said NCG mixture (G1), encompassing H 2 S and CO 2 and at least also one of H 2 , N 2 , CH 4 and/or Ar, is between 0.2 and 1.5 kg/s.
6. The method according to claim 1 , wherein the flow of said water stream (W2) is between 36 and 56 kg/s.
7. The method according to claim 1 , wherein said NCG mixture (G1), encompassing H 2 S and CO 2 and at least also one of H 2 , N 2 , CH 4 and/or Ar, is a geothermal non-condensable gas mixture.
8. The method according to claim 1 , wherein the pressure of said pressurized NCG mixture (G1) is between 7 and 11 bar.
9. The method according to claim 1 , wherein the pressure of said pressurized NCG (G1) mixture is 7, or 8, or 9, or 10 or 11 bar.
10. The method according to claim 1 , wherein said NCG mixture (G1) has a temperature of between 35 and 50° C.
11. The method according to claim 1 , wherein said NCG mixture (G1) has a temperature of between 39 and 41° C.
12. The method according to claim 1 , wherein said NCG mixture (G1) has a temperature of 40° C.
13. The method according to claim 1 , wherein said water stream (W2) has a temperature of between 6 and 35° C.
14. The method according to claim 1 , wherein said water stream (W2) has a temperature of between 8 and 30° C.
15. The method according to claim 1 , wherein said water stream (W2) has a temperature of between 10 and 25° C.
16. The method according to claim 1 , wherein said water stream (W2) has a temperature of between 12 and 20° C.
17. The method according to claim 1 , wherein said water stream (W2) has a temperature of between 13 and 17° C.
18. The method according to claim 1 , wherein said water stream (W2) has a temperature of 15° C.
19. The method according to claim 1 , wherein the flow of said NCG mixture (G1) is between 0.25 and 1.45 kg/s.
20. The method according to claim 1 , wherein the flow of said NCG mixture (G1) is between 0.4 and 1.4 kg/s.
21. The method according to claim 1 , wherein the flow of said NCG mixture (G1) is 1 kg/s.
22. The method according to claim 1 , wherein the flow of said water stream (W2) is between 45 and 55 kg/s.
23. The method according to claim 1 , wherein the flow of said water stream (W2) is between 48 and 52 kg/s.
24. The method according to claim 1 , wherein the flow of said water stream (W2) is 50 kg/s.
25. A system configured to abate at least part of hydrogen sulfide (H 2 S) and at least 50% of carbon dioxide (CO 2 ) present in a Non-Condensable gas (NCG) mixture (G1), encompassing H 2 S and CO 2 and at least also one of H 2 , N 2 , CH 4 and/or Ar, wherein the system is configured to:
pressurize-said NCG mixture (G1), encompassing H 2 S and CO 2 and at least also one of H 2 , N 2 , CH 4 and/or Ar, to a pressure between 6 and 20 bar, and
contact a stream of said pressurized NCG mixture (G1), encompassing H 2 S and CO 2 and at least also one of H 2 , N 2 , CH 4 and/or Ar, with a stream of water (W2) having a pressure between 6 and 23 bar, wherein a flow ratio, as measured in kg/s, of the stream of water (W2) to the stream of gas mixture (G1) is from 36:1.5 to 56:0.2,
absorb at least part of said H 2 S and at least 50% of said CO 2 from said pressurized NCG mixture (G1), encompassing H 2 S and CO 2 and at least also one of H 2 , N 2 , CH 4 and/or Ar, into said water stream (W2), thereby separating said at least part of said H 2 S and at least 50% of said CO 2 from at least part of said at least also one of H 2 , N 2 , CH 4 and/or Ar and producing a stream of water (W4) enriched with dissolved H 2 S and CO 2 comparable to said water stream (W2) and a stream of pressurized gas (G3), which has been depleted of at least part of the H 2 S and at least 50% of the CO 2 compared to said NCG mixture (G1), encompassing H 2 S and CO 2 and at least also one of H 2 , N 2 , CH 4 and/or Ar,
transfer-said water stream (W4) enriched with dissolved H 2 S and CO 2 :
either to an injection well for injecting said water stream (W4) into a geological reservoir, or
to a system for injection of a water stream (W5) into a geological reservoir for use of said water stream (W4) as an aid for pH-regulation of said water stream (W5).
26. The system according to claim 25 wherein the system is configured to:
contact, in an absorption column, the stream of said pressurized NCG mixture (G1), encompassing H 2 S and CO 2 and at least also one of H 2 , N 2 , CH 4 and/or Ar, with the stream of water (W2), and
absorb, in the absorption column, at least part of said H 2 S and at least 50% of said CO 2 from said pressurized NCG mixture (G1), encompassing H 2 S and CO 2 and at least also one of H 2 , N 2 , CH 4 and/or Ar, into said water stream (W2), thereby separating said at least part of said H 2 S and at least 50% of said CO 2 from at least part of said at least also one of H 2 , N 2 , CH 4 and/or Ar and producing the stream of water (W4) enriched with dissolved H 2 S and CO 2 comparable to said water stream (W2) and the stream of pressurized gas (G3), which has been depleted of at least part of the H 2 S and least 50% of the CO 2 compared to said NCG mixture (G1), encompassing H 2 S and CO 2 and at least also one of H 2 , N 2 , CH 4 and/or Ar.