HIGH PURITY CO2-3

• US 20110200517A1
• Filed: 07/24/2009
• Published: 08/18/2011
• Est. Priority Date: 07/29/2008
• Status: Active Grant

• Current Assignee: Union Engineering A/S (Pentair Plc (Ireland))
• Original Assignee: Union Engineering A/S (Pentair Plc (Ireland))
• Inventors: Find, Rasmus
• Granted Patent: US 9,545,595 B2
• Time in Patent Office: Days
• US Class Current: 423/437.1
• CPC Class Codes: B01D 2256/22 Carbon dioxide
• CPC Class Codes: B01D 2257/302 Sulfur oxides
• CPC Class Codes: B01D 2257/404 Nitrogen oxides other than dinitrogen oxide
• CPC Class Codes: B01D 2257/7027 Aromatic hydrocarbons
• CPC Class Codes: B01D 2257/708 Volatile organic compounds V.O.C.'s
• CPC Class Codes: B01D 53/1418 Recovery of products
• CPC Class Codes: B01D 53/1475 Removing carbon dioxide
• CPC Class Codes: C01B 32/50 Carbon dioxide
• 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: Y02C 20/40 of CO2
• CPC Class Codes: Y02E 20/32 Direct CO2 mitigation
• CPC Class Codes: Y02P 20/151 Reduction of greenhouse gas [GHG] emissions, e.g. CO2

Abstract

The present invention relates to a method for recovery of high purity carbon dioxide from a gaseous source and uses thereof. More specifically, the present invention relates to the production of high purity carbon dioxide, which is substantially free of nitrogen, oxygen, nitrogen oxides, sulphurous compounds and volatile organic contaminants, particularly benzene. The present invention also relates to a method for removal of benzene from a carbon dioxide feeding gas as well as the use of said high purity carbon dioxide in foodstuffs.

Claims

1. A method for the removal of benzene from a carbon dioxide feeding liquid stream comprising the steps of:

c. optionally pressurising and heating the carbon dioxide feeding stream; and

d. introducing the liquid stream, optionally obtained in step c, into a flash column.

2. The method according to claim 1, wherein the concentration of benzene in the carbon dioxide feeding gas stream is 10 ppm (mole/mole) or higher.

3. The method according to claim 1, wherein the carbon dioxide rich gaseous stream leaving the flash column is recovered.

4. The method according to claim 1, wherein the flash step d is preceded by the steps of:

a. feeding a gas comprising carbon dioxide, oxygen, N2, nitrogen oxides, volatile organic contaminants, particularly benzene, into an absorption column,

b. absorbing the gas in an absorbing agent, by which the gas is separated into a carbon dioxide-lean gas and a carbon dioxide-rich liquid, and

c. pressurising and heating the liquid obtained in step b in order to provide the liquid.

5. The method according to claim 4 wherein the flash step d is followed by the steps of:

e. pressurising the liquid leaving the flash column in step d in order to provide the liquid, and/or

f. separating the liquid obtained in step e into a carbon dioxide rich stripper off gas and a carbon dioxide-depleted liquid by means of stripping in a stripper column; and

/or

g. feeding a fraction of the carbon dioxide rich stripper off gas at the bottom of the flash column of step d.

6. The method according to claim 4, wherein the flash step is followed by at least one of the steps of:

e. pressurising the liquid leaving the flash column in step d in order to provide the liquid, and/or

f. separating the liquid obtained in step e into a carbon dioxide rich stripper off gas and a carbon dioxide-depleted liquid by means of stripping in a stripper column; and

/or

h. washing the gas obtained in step f by means of a washing column in order to produce a gas substantially free of soluble contaminants; and

/or

j. dehydrating the gas obtained in step f or h by means of a dehydrator and thereby providing a dry gas substantially free of water, oxygenates, such as acetaldehyde and traces of methanol, and volatile organics; and

/or

k. separating the gases obtained in steps, f, h or j into a gaseous mixture of carbon dioxide rich liquid and non-condensable gases by means of a condenser; and

/or

l. distilling the carbon dioxide rich liquid obtained in step k in a distillation column in order to produce liquid high purity carbon dioxide which is substantially free of nitrogen oxides, sulphurous compounds and volatile organic compounds, and/or

m. storing the carbon dioxide rich stream in a storage tank, wherein a fraction of at least one of the carbon dioxide rich streams of any of the steps h, j, k, l or m is recirculated and fed at the bottom of the flash column of step d, optionally preceded by reboiling.

7. The method according to claim 5, wherein the fraction of the carbon dioxide rich gas fed to the flash column is at least 1% (mole/mole) of the total gas.

8. The method according to claim 5, wherein the fraction of the carbon dioxide rich gas fed to the flash column is 1 to 8% (mole/mole) of the total gas.

9. The method according to claim 1, wherein the carbon dioxide feeding gas stream is flue gas.

10. The method according to claim 4, wherein the absorbing agent is an amine-based absorbing agent.

19. In a foodstuff, hospital devices or a method for enhanced oil recovery or sequestration using a carbon dioxide gas as a component, the improvement comprising using a carbon dioxide enriched gas obtained in claim 1.

20. In a foodstuff, hospital devices or a method for enhanced oil recovery or sequestration according to claim 19, wherein the foodstuff is a beverage.

11. A method for recovery of high purity carbon dioxide from a gaseous source comprising the steps of:

a. feeding a gas comprising carbon dioxide and contaminants selected from the groups consisting of oxygen, N₂, nitrogen oxides, sulphurous compounds volatile organic compounds, such as benzene, into an absorption column,

b. absorbing the gas in an absorbing agent, by which the gas is separated into a carbon dioxide-lean gas and a carbon dioxide-rich liquid,

c. pressurising and heating the liquid obtained in step b in order to provide pressurised and heated liquid,

d. separating by means of flashing the liquid obtained in step c into a contaminant-rich gas and a contaminant-depleted liquid leaving the flash column,

e. pressurising the liquid leaving the flash column in step d in order to provide a pressurised liquid,

f. separating the liquid obtained in step e into a carbon dioxide rich stripper off gas and a carbon dioxide-depleted liquid by means of stripping in a stripper column, and

g. separating the stripper off gas in two fractions, wherein a first fraction is recirculated and fed at the bottom of the flash column and a second fraction is cooled in order to provide a cooled gas.

12. The method according to claim 11, wherein the first fraction of the stripper off gas is at least 1% (mole/mole) of the total stripper off gas.

13. The method according to claim 11, wherein the first fraction of the stripper off gas is 1 to 8% (mole/mole) of the total stripper off gas.

14. The method according to claim 11, further comprising the steps of:

i. pressurising and cooling the second fraction of the gas obtained in step g in order to provide pressurised and cooled gas,

j. dehydrating the gas obtained in step i by means of a dehydrator and thereby providing a dry gas substantially free of water, oxygenates, such as acetaldehyde and traces of methanol, and volatile organics.

15. The method according to claim 11, wherein the second fraction of the gas obtained in step g prior to step j is subjected to the further steps of

h. washing the second fraction of the gas obtained in step g by means of a washing column in order to produce a gas substantially free of soluble contaminants;

and

i. pressurising and cooling the gas obtained in step h.

16. The method according to claim 11, wherein the feeding gas (G1) is flue gas.

17. The method according to claim 11, further comprising at least one of the steps of:

k. separating the gases obtained in steps, h, j or the second fraction of step g into a gaseous mixture of carbon dioxide rich liquid and non-condensable gases by means of a condenser; and

l. distilling the carbon dioxide rich liquid obtained in step k in a distillation column in order to produce liquid high purity carbon dioxide which is substantially free of nitrogen oxides, sulphurous compounds and volatile organic compounds.

18. The method according to claim 17, wherein the liquid is produced by passing the liquid leaving the condenser in step k or the distillation column in step l through a reboiler.