Modified adsorbent for dry scrubbing and use thereof

• US 20060165574A1
• Filed: 12/18/2003
• Published: 07/27/2006
• Est. Priority Date: 12/18/2002
• Status: Abandoned Application

• Current Assignee: University of Ottawa
• Original Assignee: University of Ottawa
• Inventors: Sayari, Abdelhamid
• Application Number:
  US10/539,225
• Publication Number:
  US 20060165574A1
• Time in Patent Office: Days
• US Class Current: 423/210
• CPC Class Codes: B01D 2253/10 Inorganic adsorbents
• CPC Class Codes: B01D 2253/106 Silica or silicates
• CPC Class Codes: B01D 2253/308 Pore size
• CPC Class Codes: B01D 2257/304 Hydrogen sulfide
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 53/02 by adsorption, e.g. preparative gas chromatography solid sorbent compositions B01J20/00, preparation of inorganic compounds or elements C01
• CPC Class Codes: B01D 53/0462 Temperature swing adsorption
• CPC Class Codes: B01D 53/047 Pressure swing adsorption
• CPC Class Codes: B01J 20/103 comprising silica
• CPC Class Codes: B01J 20/2803 Sorbents comprising a binder, e.g. for forming aggregated, agglomerated or granulated products
• CPC Class Codes: B01J 20/28052 Several layers of identical or different sorbents stacked in a housing, e.g. in a column
• CPC Class Codes: B01J 20/28083 being in the range 2-50 nm, i.e. mesopores
• CPC Class Codes: B01J 20/28097 being coated, filled or plugged with specific compounds
• CPC Class Codes: B01J 20/3204 Inorganic carriers, supports or substrates
• CPC Class Codes: B01J 20/3217 Resulting in a chemical bond between the coating or impregnating layer and the carrier, support or substrate, e.g. a covalent bond
• CPC Class Codes: B01J 20/3257 the functional group or the linking, spacer or anchoring group as a whole comprising at least one of the heteroatoms nitrogen, oxygen or sulfur together with at least one silicon atom, these atoms not being part of the carrier as such
• CPC Class Codes: B01J 20/3259 comprising at least two different types of heteroatoms selected from nitrogen, oxygen or sulfur with at least one silicon atom
• CPC Class Codes: B01J 20/3261 comprising a cyclic structure not containing any of the heteroatoms nitrogen, oxygen or sulfur, e.g. aromatic structures
• CPC Class Codes: B01J 20/3425 of sorbents or filter aids comprising organic materials
• CPC Class Codes: B01J 20/3458 in the gas phase
• CPC Class Codes: B01J 20/3483 : by thermal treatment not covered by groups B01J20/3441 - B01J20/3475, e.g. by heating or cooling
• CPC Class Codes: B01J 2220/56 : Use in the form of a bed
• CPC Class Codes: Y02C 20/40 : of CO2

Abstract

The present invention provides an amine functionalised adsorbent for use in dry scrubbing process. The adsorbent comprises amine functionalised mesoporous silica in which the amine groups are present at or near the surface of the silica, including within the pore walls and channels of the silica. The present invention further provides methods of preparing the adsorbent and of using the adsorbent for the adsorption of CO₂ and/or other acid gases.

Claims

1. A water-tolerant, regenerable adsorbent for use in an acid gas dry scrubbing process, said adsorbent comprising surface or framework amine-functionalised mesoporous silica or organosilica, wherein amino groups are readily accessible within the pore channels or pore walls of the mesoporous silica or organosilica.

2. The adsorbent of claim 1, wherein the amine-functionalised mesoporous silica or organosilica comprises amine-containing molecules that are covalently bound to the surface of the pore walls.

3. The adsorbent of claim 2, wherein the amine-containing molecules are amine-containing trialkoxysilane or trichlorsilane.

4. The adsorbent of claim 1, wherein the pore walls of the amine-functionalised mesoporous silica or organosilica has a hydrophobic surface and amine-containing molecules are dispersed within the hydrophobic surface.

5. The adsorbent of claim 4, wherein the amine-containing molecules are alkylamines, arylamines or alkylarylamines.

6. The adsorbent of claim 5, wherein the alkylamines are selected from the group consisting of monoethanolamine (MEA), diethanolamine (DEA), diisopropylamine (DIP), N-methyldiethanolamine (MDEA), 2-amino-2-methyl-1-propanol (AMP), polyethylenimine, β

,β

′

-hydroxyaminoethylether and combinations thereof.

7. The adsorbent of claim 1, wherein the mesoporous silica or organosilica comprises an amine-functionalised framework.

8. The adsorbent according to claim 1, wherein the acid gas is carbon dioxide.

13. A process for preparing an adsorbent according to claim 2 or 3, comprising:

(a) providing a mesoporous silica or organosilica; and

(b) grafting an amine-containing silane to the surface of the mesoporous silica or organosilica to produce the amine-functionalised mesoporous silica or organosilica.

14. A process for preparing an adsorbent according to claim 2 or 3, comprising:

(a) mixing a source of silica or organosilica, an amine-containing silane and an amphiphile molecule under conditions that facilitate self assembly to produce the amine-functionalised mesoporous silica or organosilica.

15. A process for preparing an adsorbent according to claim 2 or 3, comprising:

(a) providing a mesoporous silica or organosilica;

(b) grafting an reactive group-containing silane to the surface of the mesoporous silica or organosilica; and

(c) treating the reactive group-containing mesoporous silica or organosilica with an amine to produce the amine-functionalised mesoporous silica or organosilica.

16. A process for preparing an adsorbent according to claim 2 or 3, comprising:

(a) mixing a source of silica or organosilica, a reactive group-containing silane and an amphiphile molecule to produce the reactive group-containing mesoporous silica or organosilica; and

(b) treating the reactive group-containing mesoporous silica or organosilica with an amine to produce the amine-functionalised mesoporous silica or organosilica.

17. A process for preparing an adsorbent according to claim 4, comprising:

(a) preparing a mesoporous silica or organosilica in the presence of a swelling agent and selectively extracting the swelling agent to produce a hydrophobic layer on the surface of the mesoporous silica or organosilica; and

(b) treating the mesoporous silica or organosilica produced in step (a) with an amine to produce the amine-functionalised mesoporous silica or organosilica. (Original) A process for preparing an adsorbent according to claim 1, comprising;

(c) mixing a silica source with an amphiphilic molecule having at least one amino group under conditions that facilitate self assembly of the silica source and the amphiphile to produce the amine-functionalised mesoporous silica or organosilica,

wherein, the amine-functionalised mesoporous silica or organosilica is a mesoporous silica or organosilica having pores filled with amine-containing amphiphilic molecules.

18. A process for preparing an adsorbent according to claim 1, comprising:

(a) reacting a silica source with an amphilic molecule; and

(b) simultaneously or subsequently adding an amine-containing swelling agent.

19. A process for preparing an adsorbent according to claim 7, comprising:

(a) mixing a reactive group-containing silica source with an amphiphilic molecule to produce a mesoporous silica or organosilica having a framework comprising reactive sites; and

(b) introducing amino groups at the reactive sites to produce the amine-functionalised mesoporous silica or organosilica.

20. A system for removal of an acid gas from a gaseous stream, comprising:

(a) two or more sorbent beds comprising the adsorbent of claim 1;

(b) valve means for controlling gas flow through the sorbent beds; and

;

(c) pump means for controlling gas pressure in the system.

9. A method of dry scrubbing comprising the step of contacting a gaseous stream containing an acid gas to be removed with water-tolerant, regenerable adsorbent comprising surface or framework amine-functionalised mesoporous silica or organosilica, wherein amino groups are readily accessible within the pore channels or pore walls of the mesoporous silica or organosilica.

10. The method according to claim 9, wherein the amine-functionalised mesoporous silica or organosilica comprises amine-containing molecules that are covalently bound to the surface of the pore walls.

11. The method according to claim 9, wherein the pore walls of the amine-functionalised mesoporous silica or organosilica has a hydrophobic surface and amine-containing molecules are dispersed within the hydrophobic surface.

12. The method according to claim 9, wherein the mesoporous silica or organosilica comprises an amine-functionalised framework.

21. The system according to claim 21, wherein the acid gas is carbon dioxide.

22. The system according to claim 21, wherein the adsorbent is pelletized with a binder that is an inert secondary material.

23. The system according to claim 21, wherein the adsorbent is pelletized with a binder that is an active secondary material.