Self-Concentrating Absorbent for Acid Gas Separation

• US 20110052458A1
• Filed: 11/05/2010
• Published: 03/03/2011
• Est. Priority Date: 04/07/2006
• Status: Abandoned Application

• Current Assignee: Liang Hu
• Original Assignee: Liang Hu
• Inventors: HU, Liang
• Application Number:
  US12/940,621
• Publication Number:
  US 20110052458A1
• Time in Patent Office: Days
• US Class Current: 422/223
• CPC Class Codes: B01D 2252/202 Alcohols or their derivatives
• CPC Class Codes: B01D 2252/2023 Glycols, diols or their derivatives
• CPC Class Codes: B01D 2252/20405 Monoamines
• CPC Class Codes: B01D 2252/20484 with one hydroxyl group
• CPC Class Codes: B01D 2252/20494 Amino acids, their salts or derivatives
• CPC Class Codes: B01D 2252/504 Mixtures of two or more absorbents
• CPC Class Codes: B01D 53/1425 Regeneration of liquid absorbents
• CPC Class Codes: B01D 53/1456 Removing acid components
• CPC Class Codes: B01D 53/1493 Selection of liquid materials for use as absorbents
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: B01D 53/96 Regeneration, reactivation or recycling of reactants
• CPC Class Codes: C10L 3/10 Working-up natural gas or synthetic natural gas
• CPC Class Codes: C10L 3/102 of acid contaminants
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

A process and systems for efficiently deacidizing a gaseous mixture is described. The process and systems utilize a self-concentrating absorbent that absorbs an acid gas at reduced overall energy costs for the deacidizing operation.

Claims

1. A system for deacidizing a gaseous mixture comprising an acid gas, comprising:

an absorption unit adapted to allow contact between the gaseous mixture and an absorbent comprising an amine dissolved in a solvent at a first concentration, wherein the absorbent absorbs the acid gas to form a concentrated-amine phase, wherein the concentrated-amine phase is mechanically separable from the remaining of the absorbent, and the concentrated-amine phase comprises a concentrated amine at a concentration higher than the first concentration and an absorbed acid gas, wherein the concentrated amine comprises the amine or the amine having a chemical modification, and the absorbed acid gas comprises the acid gas or the acid gas having a chemical modification

a separation unit adapted to allow separation of the concentrated-amine phase from the remaining of the absorbent; and

a regeneration unit adapted to allow regeneration of the concentrated-amine phase, so as to obtain the acid gas and the concentrated amine.

2. The system of claim 1, wherein the separation unit is placed in a position lower than the absorption unit, so that after the absorbent absorbs the acid gas to form a gas-rich absorbent, the gas-rich absorbent moves downward from the absorption unit to the separation unit by gravity.

3. The system of claim 2, wherein the absorption unit, the separation unit and the regeneration unit are placed in a single tower, wherein the separation unit is placed in a position lower than the absorption unit and the regeneration unit is placed in a position lower than the separation unit, so that after the absorbent absorbs the acid gas, the gas-rich absorbent moves downward from the absorption unit to the separation unit by gravity, and after the step of separation, the concentrated-amine phase moves downward from the separation unit to the regeneration unit by gravity.

4. The system of claim 1, wherein the regeneration unit is placed in a position lower than the separation unit, so that after the step of separation, the concentrated-amine phase moves downward from the separation unit to the regeneration unit by gravity.

5. A system for deacidizing a gaseous mixture comprising an acid gas, comprising:

an absorption unit adapted to allow contact between the gaseous mixture and an absorbent comprising an agent dissolved in a solvent at a first concentration,

wherein the agent is selected from the group consisting of amino-acid salts, amides, alkaline salts, alkaline-earth salts, ammonium salts, ureas, alkaline metal phosphates, carbonates, borates, acid phosphites, phosphites, phosphonite, phosphinate, phosphonate, acid phosphates, pyrophosphites, bicarbonates, metaborates, diborates, tetraborates, pentaborates, and combinations thereof;

wherein the absorbent absorbs the acid gas to form a concentrated-agent phase, the concentrated-agent phase is mechanically separable from the remaining of the absorbent, and the concentrated-agent phase comprises a concentrated agent at a concentration higher than the first concentration and an absorbed acid gas,

wherein the concentrated agent comprises the agent or the agent having a chemical modification, and the absorbed acid gas comprises the acid gas or the acid gas having a chemical modification;

a separation unit adapted to allow separation of the concentrated-agent phase from the remaining of the absorbent; and

a regeneration unit adapted to allow regeneration of the concentrated-agent phase, so as to obtain the acid gas and the concentrated agent.

6. The system of claim 5, wherein the solvent comprises water, an aqueous solution containing one or more salts selected from alkaline salts, ammonium salts, alkanolamine salts, alkaline-earth salts, phosphates, acid phosphites, phosphites, phosphonite, phosphinate, phosphonate, acid phosphates, pyrophosphites, carbonates, bicarbonates, borates, metaborates, diborates, tetraborates, or pentaborates.