METHOD AND PLANT FOR AMINE EMISSION CONTROL

• US 20110308389A1
• Filed: 02/12/2010
• Published: 12/22/2011
• Est. Priority Date: 03/13/2009
• Status: Active Grant

• Current Assignee: AKER Carbon Capture Norway As (Aker Carbon Capture AS)
• Original Assignee: Aker Clean Carbon AS (Akastor ASA)
• Inventors: Graff, Oscar Fredrik, Bade, Otto Morten, Gorset, Oddvar, Woodhouse, Simon
• Granted Patent: US 9,155,990 B2
• Time in Patent Office: Days
• US Class Current: 95/166
• CPC Class Codes: B01D 2251/504 Nitric acid
• CPC Class Codes: B01D 2251/506 Sulfuric acid
• CPC Class Codes: B01D 2251/512 Phosphoric acid
• CPC Class Codes: B01D 53/1406 Multiple stage absorption
• CPC Class Codes: B01D 53/1475 Removing carbon dioxide
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

A method for eliminating or substantially reducing emission of amines (amineslip) and alkaline degradation products to the atmosphere from a plant for CO₂ capture from a flue gas, where the CO₂ is captured by counter-current flow to an absorbent in an absorption zone, the absorbent comprising an aqueous solution of one or more amine(s), to give a CO₂ lean flue gas that is released into the surroundings, and a CO₂ rich absorbent that is regenerated in a regeneration column to give a CO₂ rich gas that is treated further, and regenerated absorbent that is recycled to the absorption zone, wherein the CO₂ lean flue gas is washed with an acidic aqueous solution to remove or substantially reduce the amount of amine(s) and alkaline degradation products thereof in the gas, is described.

Claims

1. A method for eliminating or substantially reducing emission of amines and alkaline degradation products thereof to the atmosphere from a plant for CO₂ capture from a flue gas, where the CO₂ is captured by countercurrent flow to an absorbent in an absorption zone, the absorbent comprising an aqueous solution of one or more amine(s) to give a CO₂ lean flue gas that is released into the surroundings, and a CO₂ rich absorbent that is regenerated in a regeneration column to give a CO₂ rich gas that is treated further, and regenerated absorbent that is recycled to the absorption zone, where the CO₂ lean flue gas is washed with an acidic aqueous solution in a tray or a packed bed washing zone with liquid recycle to remove or substantially reduce the amount of amine(s) and alkaline degradation products thereof in the gas, wherein a part of an acid washing solution is bled off and introduced into an amine reclaimer where amine salts in solution is boiled in the presence of alkali and amine cations are liberated as free amine vapor which is reused as amine absorbent for the CO₂ capture.

2. The method according to claim 1, wherein and gaseous amine from the amine reclaimer is routed to a fractionating column for separation of gaseous ammonia from the water and amine distillate.

3. The method according to claim 1, wherein the bleed of washing solution is introduced into a pre-reactor, wherein the washing solution is reacted with an alkali and stripped by vacuum or introduction of a stripping gas to selectively remove ammonia from the washing solution before the washing solution is introduced into the amine reclaimer.

4. The method according to claim 1, wherein make-up water containing carbonic acid is supplied to a washing system from condensed water in the process and where additional acid is added to obtain a required pH.

5. The method according to claim 1, wherein a heat exchanger in an acid water wash loop is used to control water volume and concentration of dissolved compounds in the water.

6. The method according to claim 1, wherein one or more washing steps where the CO₂ lean flue gas is washed by means of water is(are) arranged between a contact zone for absorption of CO₂ and an acid wash section.

7. A method for eliminating or substantially reducing emission of amines and alkaline degradation products thereof to the atmosphere from a plant for CO₂ capture from a flue gas, where the CO₂ is captured by countercurrent flow to an absorbent in an absorption zone, the absorbent comprising an aqueous solution of one or more amine(s) to give a CO₂ lean flue gas that is released into the surroundings, and a CO₂ rich absorbent that is regenerated in a regeneration column to give a CO₂ rich gas that is treated further, and regenerated absorbent that is recycled to the absorption zone, wherein the CO₂ lean flue gas is washed with an aqueous solution of sulphuric acid, phosphoric acid, nitric acid, acetic acid, formic acid, and citric acid, to remove or substantially reduce the amount of amine(s) and alkaline degradation products thereof in the flue gas.

8. The method according to claim 7, wherein the CO₂ lean flue gas is washed by an acidic aqueous solution in a tray or in a packed bed washing zone with liquid recycle.

9. The method according to claim 7, wherein a part of an acid washing solution is bled off and introduced into an amine reclaimer where amine salts in solution is boiled in the presence of alkali and amine cations are liberated as free amine vapor which is reused as amine absorbent for CO₂ capture.

10. The method according to claim 9, wherein steam and gaseous amine from the reclaimer is routed to a fractionating column for separation of gaseous ammonia from the water and amine distillate.

11. The method according to claim 9, wherein the bleed of washing solution is introduced into a pre-reactor, wherein the washing solution is reacted with an alkali and stripped by vacuum or introduction of a stripping gas to selectively remove ammonia from the washing solution before the washing solution is introduced into the amine reclaimer.

12. The method according to claim 7, wherein a part of the acid washing solution is bled off and introduced into an amine absorbent for CO₂ capture.

13. The method according to claim 7, wherein a part of the acid washing solution is bled off to a tank for further treatment with alkaline solution, ion exchange, dialysis or bacterial decomposition.

14. The method according to claim 7, wherein make-up water containing carbonic acid is supplied to a washing system from condensed water in the process and where additional acid is added to obtain the required pH.

15. The method according to claim 7, wherein a heat exchanger in an acid water wash loop is used to control water volume and concentration of dissolved compounds in the water.

16. The method according to claim 7, wherein one or more washing steps where the CO₂ lean flue gas is washed by means of water is(are) arranged between a contact zone for absorption of CO₂ and an acid wash section.