System and method for desorption of acid gas from an absorption liquid

1. A system for desorption of acid gas ( 1 ) from an acid gas rich absorption liquid ( 2 ) having a steam part ( 3 ) and a process part ( 4 ), wherein the steam part ( 3 ) is arranged to indirectly the heat acid rich absorption liquid ( 2 ) in the process part ( 4 ) and the steam part ( 3 ) and the process part ( 4 ) are separated to prevent intermixing of fluids in the steam part ( 3 ) with fluids in the process part ( 4 ),

the system ( 1 ) comprising a desorption cylinder ( 9 ) which is adapted to rotate about a longitudinal axis of rotation A of the desorption cylinder ( 9 ), and a stationary support stand ( 19 ) for supporting the desorption cylinder ( 9 ), and means for rotating ( 18 ) the desorption cylinder ( 9 ),

wherein the steam part ( 3 ) and the process part ( 4 ) are integrated in the desorption cylinder ( 9 ),

wherein, in use, steam is supplied to the steam part ( 3 ) and the acid gas rich absorption liquid ( 2 ) is supplied to the process part ( 4 ),

wherein the process part ( 4 ) comprises a desorption chamber ( 12 ) provided with a stripper unit ( 33 ) having an integrated reboiler ( 52 ) that, in use, is arranged to receive steam supplied to the steam part ( 3 ) and the acid gas rich absorption liquid ( 2 ) supplied to the process part ( 4 ) to thereby indirectly heat the acid gas rich absorption liquid ( 2 ),

wherein the process part ( 4 ) is provided with means for discharging an acid gas lean absorption fluid ( 7 ) and having means for removing acid gas rich vapour ( 8 ),

wherein the steam part ( 3 ) is provided with means for discharging condensate ( 6 ),

wherein the stationary stand ( 19 ) is provided with a first stationary shaft ( 21 a ) and a second stationary shaft ( 21 b ) which are coaxial with the axis of rotation A of the desorption cylinder ( 9 ), and where the first stationary shaft ( 21 a ) and the second stationary shaft ( 21 b ) extend into the desorption cylinder ( 9 ),

wherein the steam part ( 3 ) is provided with a steam supply conduit ( 16 ) and a condensate outlet conduit ( 37 ) arranged along the first stationary shaft ( 21 a ), and

wherein the process part ( 4 ) is provided with a supply conduit ( 55 ) for supplying acid gas rich absorption liquid ( 2 ), and a lean absorption liquid outlet conduit ( 54 ) arranged along the second stationary shaft ( 21 b ).

2. The system according to claim 1 , wherein the desorption chamber ( 12 ) is arranged between a first liquid collecting chamber ( 11 ) and a second liquid collecting chamber ( 14 ).

3. The system according to claim 2 , wherein the first liquid collecting chamber ( 11 ) is in fluid communication with a condensate guiding chamber ( 13 ) via tubes ( 32 ) in the stripper unit ( 33 ).

4. The system according to claim 3 , wherein steam condensate is collected in the condensate guiding chamber ( 13 ) and transferred to the first liquid collecting chamber ( 11 ) via tubes ( 32 ) arranged proximal to the outer perimeter of the condensate guiding chamber ( 11 ).

5. The system according to claim 1 , wherein the desorption chamber ( 12 ) is in fluid communication with a second liquid collecting chamber ( 14 ) via an opening ( 53 ).

6. The system according to claim 5 , wherein the desorption chamber ( 12 ) is connected to the second liquid collecting chamber ( 14 ) via passages ( 57 ) provided proximal to the outer perimeter of the desorption chamber ( 12 ) for removing the acid gas lean absorption liquid ( 7 ) from the desorption chamber ( 12 ).

7. The system according to claim 1 , wherein the desorption chamber ( 12 ) comprises a liquid distributor ( 50 ) arranged in a core ( 10 ) of the desorption chamber ( 12 ).

8. The system according to claim 7 , wherein the liquid distributor ( 50 ) comprises at least one spray arm ( 59 ).

9. The system according to claim 7 , wherein the liquid distributor ( 50 ) is rotatable arranged about the axis of rotation A.

10. The system according to claim 7 , wherein the liquid distributor ( 50 ) is stationary.

11. The system according to claim 7 , wherein the desorption chamber ( 12 ) is provided with at least one layer of desorber packed bed ( 51 , 64 ) of a porous material.

12. The system according to claim 11 , wherein the at least one layer of desorber packed bed ( 64 ) is arranged between the axis of rotation A and the liquid distributor ( 50 ), wherein the packed bed ( 64 ) is arranged to rotate about the axis of rotation A.

13. The system according to claim 11 , wherein the at least one layer of desorber packed bed ( 64 ) is arranged between the axis of rotation axis A and the liquid distributor ( 50 ), wherein the desorber packed bed ( 64 ) is arranged to be stationary.

14. The system according to claim 12 , wherein the desorber packed bed ( 64 ) is provided with a vapour channel ( 63 ).

15. The system according to claim 11 , wherein at least one layer of desorber packed bed ( 51 ) is provided between the liquid distributor ( 50 ) and the stripper unit ( 33 ), and the packed bed ( 51 ) being arranged to rotate together with the desorption cylinder ( 9 ).

16. The system according to claim 11 provided with at least two layers of desorber packed bed ( 51 ) which are consecutively arranged in the radial direction between the liquid distributor ( 50 ) and the stripper unit ( 33 ), and wherein the two layers of desorber packed bed ( 51 ) are separated by a separating space ( 62 ).

17. The system according to claim 16 , wherein the desorption chamber comprises 2-10 layers of desorber packed bed ( 51 ), the layers of packed beds being consecutively arranged in the radial direction between the liquid distributor ( 50 ) and the stripper unit ( 33 ).

18. The system for desorption according to claim 1 , wherein heat is supplied throughout an entirety of the stripper unit ( 33 ).

19. The system according to claim 1 , wherein an inner part of the stripper unit ( 33 ) near a core ( 10 ) of the desorption chamber ( 12 ) is a desorber part without external heat supply whereas a periphery part of the stripper unit ( 33 ) is heated as a reboiler ( 52 ).

20. The system according to claim 11 , wherein bundles of tubes ( 32 ) of the stripper unit ( 33 ) are arranged between the desorber packed bed ( 51 ) and the outer perimeter of the desorption chamber ( 12 ).

21. The system according to claim 2 , wherein the first liquid collecting chamber ( 11 ) is provided with a diffuser ( 42 ) for discharging condensate ( 6 ) from the first liquid collecting chamber ( 11 ).

22. The system according to claim 2 , wherein the second liquid collecting chamber ( 14 ) is provided with a diffuser ( 42 ) for discharging acid gas lean absorption liquid ( 7 ) from the second liquid collecting chamber ( 14 ).

23. The system according to claim 21 , wherein the diffuser ( 42 ) is formed such that kinetic energy in the liquid ( 6 , 7 ) is converted into a pressure head when the liquid ( 6 , 7 ) is collected by the diffuser ( 42 ).

24. The system according to claim 21 , wherein the diffuser ( 42 ) is stationary and connected to a stationary shaft journal ( 22 a , 22 b ) connected to the support stand ( 19 ).

25. The system according to claim 24 , wherein the diffuser ( 42 ) is provided with at least one diffuser arm ( 44 ) having a first end ( 46 ) attached to the stationary shaft journal ( 22 a , 22 b ) and a free second end ( 47 ), and wherein the free second end ( 47 ) of the diffuser arm is provided with a liquid inlet ( 48 ) and wherein the diffuser arm comprises a diffuser conduit ( 45 ).

26. The system according to any one of the claim 25 , wherein the liquid inlet ( 48 ) of the diffuser arm ( 44 ) is arranged near a perimeter of the liquid collecting chamber ( 11 , 14 ) and is adapted to extend into a liquid layer ( 41 , 65 ) formed on the inside surface of the perimeter of the liquid collecting chamber ( 11 , 14 ) when the system is in operation.

27. The system according to claim 25 , wherein the diffuser arm ( 44 ) is formed straight in the radial direction.

28. The system according to claim 25 , wherein the diffuser arm ( 44 ) is formed curved or S-shaped in the radial direction.

29. The system according to claim 1 , wherein the acid gas ( 1 ) comprises CO 2 and/or H 2 S.

30. The system according to claim 1 , wherein the absorption liquid has an amine concentration up to 95% by weight.

31. The system according to claim 1 , wherein the acid gas rich absorption liquid ( 2 ) has viscosity of up to 1500 nPa·s.

32. The system according to claim 1 , wherein the acid gas rich absorption liquid ( 2 ) comprises at least one selected from the group consisting of mono ethanol amine (MEA), methyldiethanolamine (MDEA), and diisopropanolamine (DEA).

33. The system according to claim 1 , wherein the acid gas rich absorption liquid ( 2 ) comprises additives having promotive effect.

34. A method for desorption of acid gas from an acid gas rich absorption liquid by a system ( 1 ) having a steam part ( 3 ) and a process part ( 4 ), wherein the steam part ( 3 ) is arrange to indirectly heat the acid rich absorption liquid in the process part ( 4 ) and the steam part ( 3 ) and the process part ( 4 ) are separated to prevent intermixing of fluids in the steam part ( 3 ) with fluids in the process part ( 4 ), and the steam part ( 3 ) and process part ( 4 ) are integrated in a desorption cylinder ( 9 ), wherein a stationary stand ( 19 ) is provided with a first stationary shaft ( 21 a ) and a second stationary shaft ( 21 b ) which are coaxial with an axis of rotation A of the desorption cylinder ( 9 ), and where the first stationary shaft ( 21 a ) and the second stationary shaft ( 21 b ) extend into the desorption cylinder ( 9 ), wherein the steam part ( 3 ) is provided with a steam supply conduit ( 16 ) and a condensate outlet conduit ( 37 ) arrange along the first stationary shaft ( 21 a ) and the process part ( 4 ) is provided with a supply conduit ( 55 ) for supplying acid gas rich absorption liquid ( 2 ), and a lean absorption liquid outlet conduit ( 54 ) arranged along the second stationary shaft ( 21 b ),

the method comprising the steps of

rotating the desorption cylinder ( 9 ) about a longitudinal axis of rotation A of the desorption cylinder ( 9 ),

distributing acid gas rich absorption liquid ( 2 ) in a desorption chamber ( 12 ) in the process part ( 4 ), the desorption chamber ( 12 ) comprising a stripper unit ( 33 ) having an integrated reboiler ( 52 ) that, in use, is arranged to receive steam supplied to the steam part ( 3 ) and acid gas rich absorption liquid ( 2 ) supplied to the process part ( 4 ) to thereby indirectly heat the acid gas rich absorption liquid ( 2 ),

forcing the absorption liquid to move towards a perimeter of the desorption chamber ( 12 ) by effect of centrifugal force,

feeding steam ( 5 ) to the steam part ( 3 ) and to the stripper unit ( 33 ),

stripping the acid gas rich absorption liquid ( 2 ) thereby forming acid gas rich vapour ( 8 ),

removing acid gas rich vapour ( 8 ) from the desorption chamber ( 12 ),

discharging acid gas lean absorption liquid ( 7 ) from the process part ( 4 ) by discharging means, discharging condensate from the steam part ( 3 ) by discharging means,

resulting in a stream of acid gas lean absorption liquid, a stream of acid gas rich vapour and a stream of condensate ( 6 ).

35. The method according to claim 34 further comprising distributing acid gas rich absorption liquid ( 2 ) by a liquid distributor ( 50 ) onto a desorber packed bed ( 51 ) arranged within the desorption chamber ( 12 ).

36. The method according to claim 34 further comprising forcing the acid gas rich absorption liquid ( 2 ) to move through at least one layer of desorber packed bed ( 51 ) by effect of centrifugal force.

37. The method according to claim 34 further comprising moving vapour ( 8 ) released from the acid gas rich absorption liquid ( 2 ) in a direction towards the desorption chamber ( 9 ).

38. The method according to claim 34 further comprising receiving steam condensate by a steam guiding chamber ( 13 ), and returning the steam condensate to a first liquid collecting chamber ( 11 ).

39. The method according to claim 38 further comprising collecting the steam condensate in the first liquid collecting chamber ( 11 ).

40. The method according to claim 34 further comprising transferring the acid gas lean absorption liquid ( 2 ) to a second collecting chamber ( 11 ).

41. The method according to claim 34 further comprising collecting the acid gas lean absorption liquid ( 2 ) in a second liquid collecting chamber ( 14 ).

42. The method according to claim 34 comprising forming a liquid layer on at least a portion of an outer perimeter of a liquid collecting chamber ( 11 , 14 ) by rotating the desorption cylinder ( 9 ).

43. The method according to claim 34 comprising recovering energy supplied to the system ( 1 ).

44. The method according to claim 34 comprising discharging condensate ( 6 ) by a first diffuser ( 42 ).

45. The method according to claim 34 comprising discharging acid gas lean absorption liquid ( 7 ) by a second diffuser ( 42 ).

46. The method according to claim 34 comprising recovering energy by converting kinetic energy in a liquid layer ( 41 , 65 ) into a pressure head by a diffuser ( 42 ) and using the pressure head to discharge liquid from a liquid collecting chamber ( 11 , 14 ).

47. The method according to claim 34 comprising operating the system ( 1 ) with a pressure difference between the steam part ( 3 ) and the process part ( 4 ), the pressure difference being up to 10 Bar.