Ionic liquid solvent and gas purification method using the same

Patent metadata

Field	Value
Publication number	US-9358497-B2
Application number	US-201013823707-A
Country	US
Kind code	B2
Filing date	Sep 26, 2010
Priority date	Sep 26, 2010
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

An ionic liquid solvent and gas purification method using the same are provided. The ionic liquid solvent consists of a main absorbent, a regulator for the main absorbent, an auxiliary absorbent, an activator, an antioxidant and water. The ionic liquid involves a low synthetic cost, low viscosity and high absorption capacity, and can be easily regenerated and recycled. The method, compared with traditional processes, has advantages such as a greater absorption capability and lower operation cost.

First claim

The invention claimed is:

1. An ionic liquid solvent for gas purification and separation, consisting of a main absorbent, a regulator for the main absorbent, an auxiliary absorbent, an activator, an antioxidant and water, wherein based on the total weight of the ionic liquid solvent, the ionic liquid solvent comprises 2-95 wt % of alkylolamine functionalized ionic liquid as the main absorbent; 0-30 wt % of heterocyclic ionic liquid or amino acid ionic liquid as the regulator for the main absorbent; 0.1-30 wt % of alkylolamine organic solvent as the auxiliary absorbent; 0-5 wt % of activator; 0.1-1 wt % of antioxidant and 0.1-50 wt % of water.

2. The ionic liquid solvent according to claim 1 , wherein the alkylolamine functionalized ionic liquid, as the main absorbent, has a concentration of 20-80 wt %.

3. The ionic liquid solvent according to claim 1 , wherein the regulator for the main absorbent has a concentration of 0.5-5 wt %.

4. The ionic liquid solvent according to claim 1 , wherein the alkylolamine organic solvent, as the auxiliary absorbent, has a concentration of 0.5-20 wt %.

5. The ionic liquid solvent according to claim 1 , wherein the alkylolamine functionalized ionic liquid has a structural formula of AB, wherein A has a structural formula shown as follow:

wherein R 1 , R 2 , R 3 satisfy the following requirements: R 1 is C n H 2n+1 OH (1≦n≦15), R 2 and R 3 are H or C m H 2m+1 (OH) x (1≦m≦15, x=1 or 0), respectively; and B is one or more anions selected from the group consisting of Cl − , Br − , I − , BF 4 − , PF 6 − , OH − , CO 3 − , HCO 3 − , CH 3 COO − , RO − , PhO − , Tf 2 N − , CF 3 SO 3 − , SbF 6 − , SO 4 2− , HSO 4 − , PO 4 3− , H 2 PO 4 − , FeCl 4 − , AlCl 4 − , AlBr 4 − , AlI 4 − , SCN − , NO 3 − , and CF 3 CF 2 CF 2 CF 2 SO 3 − .

6. The ionic liquid solvent according to claim 1 , wherein the heterocyclic ionic liquid, as the regulator for the main absorbent, includes one or more of spiropyrans, furans, pyridines, thiophenes, imidazoles, pyrroles, pyrazoles, azoles, thiazoles, indoles, pyrazines, pyridazines, quinolines, morpholines, quinazolines, piperazines, piperidines, oxazoles, oxazolines and oxazines heterocyclic compound ionic liquids; and the anion of the heterocyclic ionic liquid comprises one or more of Cl − , Br − , I − , BF 4 − , PF 6 − , OH − , CO 3 2− , HCO 3 − , CH 3 COO − , RCOO − , RO − , PhO − , Tf 2 N − , CF 3 SO 3 − , SbF 6 − , SO 4 2− , HSO 4 − , PO 4 3− , H 2 PO 4 − , FeCl 4 − , AlCl 4 − , AlBr 4 − , AlI 4 − , SCN − , NO 3 − and CF 3 CF 2 CF 2 CF 2 SO 3 − .

7. The ionic liquid solvent according to claim 1 , wherein the alkylolamine organic solvent, as the auxiliary absorbent, has a structural formula shown as follow:

wherein R 1 , R 2 , R 3 satisfy the following requirements: R 1 is C n H 2n+1 OH (1≦n≦15), R 2 and R 3 are H or C m H 2m+1 (OH) x (1≦m≦15, x=1 or 0), respectively.

8. The ionic liquid solvent according to claim 1 , wherein the alkylolamine organic solvent, as the auxiliary absorbent, is one or more of ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine and diethylene glycol amine.

9. The ionic liquid solvent according to claim 1 , wherein the activator is one or more of aminoacetic acid, imidazole, methylimidazole, sulfolane, piperazine, hydroxyethyl diamine, ethylenediamine, and tetramethylpropylenediamine.

10. The ionic liquid solvent according to claim 1 , wherein the antioxidant is at least one of hydroquinone, tannin and anthraquinone.

11. A gas purification method using the ionic liquid solvent according to claim 1 , wherein the ionic liquid solvent absorbs gas under a pressure of 0.1 MPa-10 MPa, at a temperature of 1° C.-98° C.; and desorbs gas under a pressure of 0.1 MPa-5 MPa, at a temperature of 40° C.-300° C.

12. The method according to claim 10 , wherein the gas to be purified include one or more of carbon dioxide, sulfur dioxide, hydrogen chloride, hydrogen sulfide, oxynitride (NO x ), sulfoxide (SO x ), ammonia, hydrogen, carbon monoxide, methane, ethane, propane, methyl ether, diethyl ether, ethylene, propylene, acetylene, formaldehyde, formic acid, monochloromethane, dichloromethane, chlorine, and oxygen.

13. The method according to claim 10 , wherein the absorption of the gas is carried out in a multistage absorption tower.

14. The method according to claim 13 , wherein the multistage absorption tower is a bubble tower, a packed tower, or an empty tower.

15. The method according to claim 13 , wherein the desorption of the gas is carried out in a multistage desorption tower.

16. The method according to claim 15 , wherein the multistage absorption tower and multistage desorption tower have continuously distributed scale-like structures, and the scale-like structures have trapezoidal or rounded cross sections.

17. The method according to claim 15 , wherein a fresh solvent and a lean solution, after mixed, are fed through the upper segment of the multistage absorption tower; and a semi-lean solution is fed through the middle of the tower; the two feeding flows are contacted with and absorb the feed gas from the bottom of the tower in a countercurrent; the purified gas is discharged from the top of the tower and enters into the purified gas separator, so as to remove the liquid carried thereby; the absorbed gas enters into the liquid phase and form a rich liquid stream; then the rich liquid stream is discharged from the bottom of the tower and enters into a rich liquid flasher to remove other gases carried thereby; after that, the rich liquid stream is passed through a solvent heat exchanger and enters into the upper segment of the multistage desorption tower; in the multistage desorption tower, the rich liquid stream desorbs thermally and the desorbed gas is discharged from the top of the tower; the discharged gas then is passed through a regeneration cooler and enters a regeneration gas separator to generate a highly purified regeneration gas; the liquid discharged from the bottom of the regeneration gas separator is fed into the bottom of a stripping regeneration tower, and further thermally desorbs; then a full-lean solution is obtained, and discharged from the bottom of the tower; subsequently, the full-lean solution, after subjected a heat exchange with a semi-lean solution discharged from the lower segment of the desorption tower, is passed through a lean solution pump and a heat exchanger, mixed with a fresh solvent, then recycled; the semi-lean solution after the heat exchange is pumped directly into the middle segment of the absorption tower and recycled.

Assignees

• Zhang Xiangping
• Zhao Yansong
• Zeng Shaojuan
• Zhang Suojiang
• Dong Haifeng
• Zhen Yingpeng
• Huang Lei
• Inst Process Eng Cas

Inventors

• Zhang Xiangping
• Zhao Yansong
• Zeng Shaojuan
• Zhang Suojiang
• Dong Haifeng
• Zhen Yingpeng
• Huang Lei

Classifications

• Y02C10/06

  Cross-Sectional Technologies · mapped topic

• B01D2257/504

  Carbon dioxide · CPC title

• B01D2257/304

  Hydrogen sulfide · CPC title

• B01D2252/30

  Ionic liquids and zwitter-ions · CPC title

• B01D2252/20478

  Alkanolamines · CPC title