Cyclone separation and recovery of carbon dioxide from heated liquid absorbent

Patent metadata

Field	Value
Publication number	US-2016166951-A1
Application number	US-201414572267-A
Country	US
Kind code	A1
Filing date	Dec 16, 2014
Priority date	Dec 16, 2014
Publication date	Jun 16, 2016
Grant date	—

Abstract

A process and system for improving the efficiency of regenerating a CO 2 -rich liquid absorbent stream following contact in an absorption zone with, e.g., a flue gas stream from which it has absorbed CO 2 , and recovering a substantially pure stream of includes passing the pressurized liquid sorbent through a heating zone to heat it to the desorption temperature, e.g., to about 80°-85° C. for aqueous K 2 CO 3 sorbent, introducing the heated liquid sorbent into a cyclone separation zone where the combination of increased temperature, reduced pressure and the centrifugal forces on the liquid/gas mixture result in a relatively more rapid and efficient separation of the CO 2 from the liquid sorbent from which it has been released. The CO 2 -lean liquid sorbent descends to the bottom of the cyclone separator and is recovered, cooled and recycled to the absorption zone; the CO 2 withdrawn from the cyclone separation zone passes through a condenser to remove moisture and any other condensates present, and the CO 2 is recovered for storage or use in downstream processes.

First claim

1 . A process for the separation and recovery of carbon dioxide from a CO 2 -rich liquid sorbent stream derived from a CO 2 desorption unit, the process comprising:
a. increasing the temperature of the CO 2 -rich sorbent from the CO 2 sorption temperature by passing the stream in a conduit under pressure through a heating zone; b. passing the heated pressurized CO 2 -rich sorbent through a sorbent conduit in a generally linear flow path; c. introducing the heated CO 2 -rich sorbent stream into a cyclone separator under reduced pressure conditions to effect the desorption of CO 2 from the sorbent and simultaneously passing the flowing sorbent into a curvilinear conduit which at least terminates in a decreasing spiral flow path while maintaining a non-turbulent flow of the sorbent; d. passing the liquid sorbent from the curvilinear conduit through an opening into an upper section of a closed cylindrical vertical cyclone member that is in fluid communication with the curvilinear conduit; e. recovering CO 2 desorbed from the sorbent in a central open region of the vertical cyclone member and passing the CO 2 through a CO 2 discharge conduit in fluid communication with the upper region of the vertical cyclone member; f. receiving at the base of the vertical cyclone member a CO 2 -lean liquid sorbent from which the CO 2 was desorbed; g. recycling the CO 2 -lean sorbent stream to the CO 2 desorption unit.

2 . The process of claim 1 which includes
h. passing the CO 2 recovered from the vertical cyclone member to a condenser in a condensing zone to separate from the CO 2 from any water vapor and other compounds desorbed from the liquid sorbent; and
i. recovering a substantially pure stream of CO 2 gas from the condensing zone.

3 . The process of claim 1 in which the vertical cyclone member is of generally circular cross-section.

4 . The process of claim 3 , in which diameter of the circular cross-section is uniform.

5 . The process of claim 1 , where the cross-sectional area of the curvilinear conduit increases over its length.

6 . The process of claim 1 in which the curvilinear conduit circumscribes an angle in the range of from 150° to 250°.

7 . The process of claim 1 in which the liquid sorbent follows the path of a descending spiral in the curvilinear conduit before passing into the vertical cyclone member.

8 . The process of claim 1 in which the spiral flow path has a decreasing diameter.

9 . The process of claim 1 in which the curvilinear flow path is comprised of arcuate sections having different diameters.

10 . The process of claim 1 in which the CO 2 -lean sorbent recycle stream from step 1(g) is passed in heat exchange with the CO 2 -rich sorbent from the CO 2 desorption unit.

11 . The process of claim 1 in which the liquid sorbent is an aqueous solution of K 2 CO 3 and the sorbent is heated in step 1(a) to a temperature in the range from 80° C. to 85° C.

12 . The process of claim 10 in which the temperature of the recycled CO 2 -lean sorbent is reduced to 40° C. or lower for return to the CO 2 desorption unit.

Assignees

• Saudi Arabian Oil Co

Inventors

• Hammad Ahmad D
• Akhras Abdul Rahman Zafer
• Yusuf Zaki
• Rasheedi Nayif A
• Al-Qahtani Amjaad

Classifications

• B01D53/1425 Primary

  Regeneration of liquid absorbents · CPC title

• B01D19/0057 Primary

  the centrifugal movement being caused by a vortex, e.g. using a cyclone, or by a tangential inlet · CPC title

• B01D19/0068

  General arrangements, e.g. flowsheets (B01D19/0063 takes precedence) · CPC title

• B01D53/1475

  Removing carbon dioxide · CPC title

• Y02C20/40

  of CO2 · CPC title