CARBON DIOXIDE RECOVERY APPARATUS AND CARBON DIOXIDE RECOVERY METHOD

• US 20150298054A1
• Filed: 03/25/2015
• Published: 10/22/2015
• Est. Priority Date: 04/18/2014
• Status: Abandoned Application

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Murai, Shinji, Maezawa, Yukishige, Hodotsuka, Masatoshi, MURAOKA, Daigo
• Application Number:
  US14/668,063
• Publication Number:
  US 20150298054A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B01D 2252/204 Amines
• CPC Class Codes: B01D 2252/20478 Alkanolamines
• CPC Class Codes: B01D 2252/602 Activators, promoting agents, catalytic agents or enzymes
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 2258/0283 Flue gases
• CPC Class Codes: B01D 2259/65 Employing advanced heat integration, e.g. Pinch technology
• CPC Class Codes: B01D 53/1425 Regeneration of liquid absorbents
• CPC Class Codes: B01D 53/1475 Removing carbon dioxide
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: B01D 53/78 with gas-liquid contact
• CPC Class Codes: F23J 15/04 using washing fluids scrubbers for removing solids only F23J15/022
• CPC Class Codes: F23J 2215/50 Carbon dioxide
• CPC Class Codes: F23J 2219/40 Sorption with wet devices, e.g. scrubbers
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y02E 20/32 Direct CO2 mitigation

Abstract

The CO₂ recovery apparatus 10A includes: an absorption tower 11 in which a discharge gas 21 is contacted with a second lean solution 22B to allow the second lean solution 22B to absorb CO₂; a temperature regulator 12 in which a first rich solution 23A discharged from the absorption tower is heated or cooled to allow the first rich solution 23A to be a solution in which a precipitate containing the reaction accelerator is dispersed; a phase separator 13 in which a second rich solution 23B passed through the temperature regulator 12 is separated into an amino group-containing compound rich phase 31 and a reaction accelerator rich phase 32; a regeneration tower 15 in which a third rich solution 23C is regenerated; and a solution mixing line L13A through which a reaction accelerator rich solution 34 is supplied to a first lean solution 22A discharged from the regeneration tower 15.

Claims

1. A carbon dioxide recovery apparatus comprising:

an absorption tower in which a discharge gas containing CO₂ is contacted with an absorbing liquid comprising an amino group-containing compound with steric hindrance and a reaction accelerator to allow said absorbing liquid to absorb CO₂;

a temperature regulation unit in which a first rich solution discharged from said absorption tower is heated or cooled to be a solution in which a precipitate comprising said reaction accelerator is dispersed or to be a solution comprising a reaction accelerator rich phase comprising a large amount of said reaction accelerator compared to said first rich solution;

a phase separation unit in which a second rich solution, said second rich solution being an absorbing liquid passed through said temperature regulation unit, is separated into an amino group-containing compound rich phase and a reaction accelerator rich phase to discharge said amino group-containing compound rich phase as a third rich solution and to discharge said reaction accelerator rich phase as a reaction accelerator rich solution, said amino group-containing compound rich phase comprising a large amount of an amino group-containing compound compared to said first rich solution, and said reaction accelerator rich phase comprising a large amount of said reaction accelerator compared to said first rich solution;

a regeneration tower in which CO₂ contained in said third rich solution is separated to regenerate said third rich solution; and

a solution mixing line through which said reaction accelerator rich solution is supplied to a first lean solution which is an absorbing liquid discharged from said regeneration tower.

2. The apparatus according to claim 1, wherein said amino group-containing compound is one or more selected from the group consisting of alkanolamines.

3. The apparatus according to claim 1, wherein said amino group-containing compound is represented by said following general formula (1):

4. The apparatus according to claim 1, further comprising a first gas/liquid separation unit for separating CO₂ contained in a second lean solution, in which said reaction accelerator rich solution is mixed into said first lean solution, or said reaction accelerator rich solution.

5. The apparatus according to claim 1, further comprising a first heat exchange unit in which heat exchange between a second lean solution, in which said reaction accelerator rich solution is mixed into said first lean solution, and said third rich solution is carried out.

6. The apparatus according to claim 4, wherein

said first rich solution is heated or cooled to 20 to 60°

C. to allow said second rich solution to be a solution in which a precipitate containing said reaction accelerator is dispersed in said temperature regulation unit; and

CO₂ contained in said second lean solution is separated in said first gas/liquid separation unit.

7. The apparatus according to claim 4, further comprising a second heat exchange unit in which heat exchange between said reaction accelerator rich solution and CO₂ discharged from said regeneration tower is carried out, wherein

the first rich solution is heated or cooled to 20 to 60°

C. to allow said second rich solution to be a solution in which a precipitate containing said reaction accelerator is dispersed in said temperature regulation unit; and

CO₂ contained in said reaction accelerator rich solution subjected to heat exchange in said second heat exchange unit, is separated in said first gas/liquid separation unit.

8. The apparatus according to claim 5, further comprising a second gas/liquid separation unit which is disposed between said second heat exchange unit and said regeneration tower and which separates CO₂ from said third rich solution.

9. The apparatus according to claim 4, wherein

said temperature regulation unit is a third heat exchange unit in which heat exchange between said second lean solution and said first rich solution is carried out,

in said temperature regulation unit, said first rich solution is heated to 60 to 120°

C. to allow said second rich solution to be a mixed phase comprising an amino group-containing compound rich phase and a reaction accelerator rich phase,

wherein said amino group-containing compound rich phase comprising a large amount of an amino group-containing compound compared to said first rich solution, and said reaction accelerator rich phase comprising a large amount of said reaction accelerator compared to said first rich solution; and

CO₂ is separated from said second lean solution in said first gas/liquid separation unit.

10. The apparatus according to claim 9, further comprising a fourth heat exchange unit in which heat exchange between said reaction accelerator rich solution and carbon dioxide gas discharged from said regeneration tower is carried out.

11. The apparatus according to claim 1, further comprising a first CO₂ discharge mixing line for mixing CO₂ discharged from said regeneration tower with CO₂ discharged from a first gas/liquid separation unit for separation of CO₂ contained in a second lean solution or said reaction accelerator rich solution, wherein said second lean solution is a solution in which said reaction accelerator rich solution is mixed into said first lean solution.

12. The apparatus according to claim 9, further comprising a second CO₂ discharge mixing line for mixing CO₂ discharged from said regeneration tower with CO₂ discharged from said phase separation unit.

13. A carbon dioxide recovery method comprising:

a CO₂ recovery step of contacting a discharge gas containing CO₂ with an absorbing liquid comprising an amino group-containing compound with steric hindrance and a reaction accelerator to allow said absorbing liquid to absorb CO₂ in an absorption tower;

a temperature regulation step of heating or cooling a first rich solution which is an absorbing liquid discharged from said absorption tower to allow said first rich solution to be a solution in which a precipitate comprising said reaction accelerator is dispersed or to be a solution comprising a reaction accelerator rich phase comprising a large amount of said reaction accelerator compared to said first rich solution in a temperature regulation unit;

a phase separation step of separating a second rich solution, said second rich solution being an absorbing liquid passed through said temperature regulation unit, into an amino group-containing compound rich phase and a reaction accelerator rich phase to discharge said amino group-containing compound rich phase as a third rich solution and to discharge said reaction accelerator rich phase as a reaction accelerator rich solution, said amino group-containing compound rich phase comprising a large amount of an amino group-containing compound compared to said first rich solution, and said reaction accelerator rich phase comprising a large amount of said reaction accelerator compared to said first rich solution;

a regeneration step of separating CO₂ contained in said third rich solution to regenerate said third rich solution in a regeneration tower; and

a solution mixing step of mixing a first lean solution which is an absorbing liquid discharged from said regeneration tower with said reaction accelerator rich solution.

14. The method according to claim 13, wherein at least one selected from the group consisting of alkanolamines is used as said amino group-containing compound.

15. The method according to claim 13, wherein said amino group-containing compound is represented by said following general formula (1):

16. The method according to claim 13, further comprising a first gas/liquid separation step of separating CO₂ contained in a second lean solution, in which said reaction accelerator rich solution is mixed into said first lean solution, or said reaction accelerator rich solution.

17. The method according to claim 13, further comprising a first heat exchange step of carrying out heat exchange between a second lean solution, in which said reaction accelerator rich solution is mixed into said first lean solution, and said third rich solution.

18. The method according to claim 16, wherein

in said temperature regulation step, heat exchange between said second lean solution and said first rich solution is carried out,

said first rich solution is heated to 60 to 120°

C. to allow said second rich solution to be a mixed phase comprising an amino group-containing compound rich phase and a reaction accelerator rich phase,

wherein said amino group-containing compound rich phase comprising a large amount of an amino group-containing compound compared to said first rich solution, and said reaction accelerator rich phase comprising a large amount of said reaction accelerator compared to said first rich solution; and

separating CO₂ contained in said second lean solution in said first gas/liquid separation step.

19. The method according to claim 18, wherein heat exchange between said reaction accelerator rich solution and a CO₂ gas discharged from said regeneration tower is carried out.