Carbon dioxide absorbent and method for absorbing and desorbing carbon dioxide

Patent metadata

Field	Value
Publication number	US-2016101385-A1
Application number	US-201514881796-A
Country	US
Kind code	A1
Filing date	Oct 13, 2015
Priority date	Oct 14, 2014
Publication date	Apr 14, 2016
Grant date	—

Abstract

A carbon dioxide absorbent is disclosed. The absorbent comprises organic amine, amino acid, and water, wherein said organic amine comprises tertiary amine and primary amine and/or secondary amine; and wherein amino acid is excess based on a stoichiometrical ratio of organic amine to amino acid in a reaction. A method for absorbing and desorbing carbon dioxide is further disclosed. In the absorbent system provided by the present disclosure, the conversion between primary (secondary) amine and (secondary) tertiary amine can be realized under the catalytic effect of amino acid with the changing of temperature, and carbon dioxide can be absorbed and desorbed effectively under a relatively low temperature.

First claim

1 . A carbon dioxide absorbent, comprising organic amine, amino acid, and water, wherein said organic amine comprises tertiary amine and primary amine and/or secondary amine; and
wherein amino acid is excess based on a stoichiometrical ratio of organic amine to amino acid in a reaction.

2 . The absorbent according to claim 1 , wherein said primary amine is one or more selected from a group consisting of monoethanolamine, methyl monoethanolamine, 2-amino-2-methyl-1-propanol, β-hydroxyethylenediamine, and 3-(methylamino)propylamine; and/or
wherein said secondary amine is one or more selected from a group consisting of diethanolamine, tertiarybutylamineethoxyethanol (TBEE), piperazine and derivatives thereof, and morpholine and derivatives thereof.

3 . The absorbent according to claim 1 , wherein a molecular structural formula of said tertiary amine is:

wherein a number of C atom of R 1 , R 2 , or R 3 ranges from 0 to 3; and
wherein R 1 , R 2 , and R 3 each is alkyl, hydroxyalkyl, or hydroxyl, and at least one of R 1 , R 2 , and R 3 is hydroxyalkyl, or hydroxyl.

4 . The absorbent according to claim 1 , wherein said amino acid is one or more selected from a group consisting of the amino acid with the following molecular structural formula:

wherein a number of C atom of R1, R2, R3, or R4 ranges from 0 to 3, and R1, R2, R3, and R4 each is selected from a group consisting of hydrogen, alkyl, and hydroxyalkyl.

5 . The absorbent according to claim 1 , wherein based on a total weight of the absorbent, said absorbent comprises 10 wt % to 45 wt % amino acid, 5 wt % to 35 wt % organic amine, and water as a balance.

6 . The absorbent according to claim 1 , wherein a molar ratio of organic amine to amino acid is 1:(1-3).

7 . The absorbent according to claim 6 , wherein a molar ratio of organic amine to amino acid is 1:(1.1-2.4).

8 . The absorbent according to claim 7 , wherein a molar ratio of organic amine to amino acid is 1:(1.1-1.8).

9 . The absorbent according to claim 1 , wherein in said absorbent, a molar ratio of a total amount of primary amine and secondary amine to amino acid is 1:(1.5-5).

10 . The absorbent according to claim 9 , wherein in said absorbent, a molar ratio of a total amount of primary amine and secondary amine to amino acid is 1:(1.8-3.2).

11 . The absorbent according to claim 10 , wherein in said absorbent, a molar ratio of a total amount of primary amine and secondary amine to amino acid is 1:(2-2.5).

12 . The absorbent according to claim 1 , wherein the organic amine is mixed amine of primary amine and tertiary amine.

13 . A carbon dioxide absorbent, comprising organic amine, amino acid, and water,
wherein said organic amine is mixed amine of tertiary amine and primary amine and/or secondary amine, and a molar ratio of a total amount of primary amine and secondary amine to amino acid is 1:(1.8-3.2); and wherein said primary amine is at least one selected from a group consisting of 2-amino-2-methyl-1-propanol, monoethanolamine, and 3-(methylamino)propylamine, said secondary amine is tertiarybutylamineethoxyethanol (TBEE), said tertiary amine is at least one selected from a group consisting of N-methyldiethanolamine, triethanolamine, and 2-(diisopropylamino)ethanol, and said amino acid is preferably at least one selected from a group consisting of alanine, aminoacetic acid, and serine.

14 . A method for absorbing and desorbing carbon dioxide, comprising the following steps:
a) dissolving organic amine and amino acid into water to obtain absorbent, wherein amino acid is excess based on a stoichiometrical ratio of organic amine to amino acid in a reaction; b) heating the absorbent and keeping the absorbent under an absorption temperature, and adding gas sample containing carbon dioxide to a bottom of the absorbent, so that carbon dioxide is absorbed by the absorbent; and c) heating the solution with carbon dioxide absorbed therein under stirring and keeping the solution under a desorption temperature, so that the carbon dioxide absorbed therein is desorbed and the absorbent is regenerated.

15 . The method according to claim 14 ,
wherein said primary amine is one or more selected from a group consisting of monoethanolamine, methyl monoethanolamine, 2-amino-2-methyl-1-propanol, β-hydroxyethylenediamine, and 3-(methylamino)propylamine; and/or wherein said secondary amine is one or more selected from a group consisting of diethanolamine, tertiarybutylamineethoxyethanol (TBEE), piperazine, and morpholine; and/or wherein a molecular structural formula of said tertiary amine is:

wherein a number of C atom of R 1 , R 2 , or R 3 ranges from 0 to 3, R 1 , R 2 , and R 3 each is alkyl, hydroxyalkyl, or hydroxyl, and at least one of R 1 , R 2 , and R 3 is hydroxyalkyl, or hydroxyl; and
wherein said amino acid is one or more selected from a group consisting of the amino acid with the following molecular structural formula:

wherein a number of C atom of R1, R2, R3, or R4 ranges from 0 to 3, and R1, R2, R3, and R4 each is selected from a group consisting of hydrogen, alkyl, and hydroxyalkyl.

16 . The method according to claim 14 , wherein a molar ratio of organic amine to amino acid is 1:(1-3).

17 . The method according to claim 14 , wherein in said absorbent, a molar ratio of a total amount of primary amine and secondary amine to amino acid is 1:(1.8-3.2).

18 . The method according to claim 14 , wherein said absorption temperature ranges from 25° C. to 60° C.; and/or
wherein said desorption temperature ranges from 81° C. to 119° C.

19 . The method according to claim 14 , wherein in step b), a flow-rate of the gas sample containing carbon dioxide, calculated in terms of carbon dioxide, ranges from 60 ml/min to 120 ml/min.

20 . The method according to claim 14 , wherein said absorption temperature ranges from 36° C. to 50° C., said desorption temperature ranges from 91° C. to 104° C., and a flow-rate of the gas sample containing carbon dioxide, calculated in terms of carbon dioxide, ranges from 70 ml/min to 100 ml/min.

Assignees

• China Petroleum & Chemical
• Nanjing Chem Ind Co Res Inst

Inventors

• Mao Songbai
• Huang Zhongbin

Classifications

• B01D2252/20447

  containing a piperazine-ring · CPC title

• B01D2252/20426

  Secondary amines · CPC title

• B01D2252/20452

  containing a morpholine-ring · CPC title

• B01D2252/20431

  Tertiary amines · CPC title

• B01D2252/504

  Mixtures of two or more absorbents · CPC title