CARBON DIOXIDE ABSORBENT, CARBON DIOXIDE SEPARATING APPARATUS, AND REFORMER

• US 20080072760A1
• Filed: 03/15/2007
• Published: 03/27/2008
• Est. Priority Date: 09/27/2006
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Imada, Toshihiro, Kato, Yasuhiro, Kato, Masahiro
• Granted Patent: US 7,588,630 B2
• Time in Patent Office: Days
• US Class Current: 96/145
• CPC Class Codes: B01D 2253/106 Silica or silicates
• CPC Class Codes: B01D 2256/22 Carbon dioxide
• 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: B01J 20/10 comprising silica or silicate
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

A carbon dioxide absorbent includes lithium silicate containing lithium orthosilicate and lithium metasilicate, the lithium metasilicate being contained in an amount of 5% by weight or more to 40% by weight or less with respect to the total amount of lithium orthosilicate and lithium metasilicate, where the lithium metasilicate produced by reaction of the lithium orthosilicate and carbon dioxide is excluded.

Claims

1. A carbon dioxide absorbent comprising:

lithium silicate containing lithium orthosilicate and lithium metasilicate, the lithium metasilicate being contained in an amount of 5% by weight or more to 40% by weight or less with respect to the total amount of lithium orthosilicate and lithium metasilicate, where the lithium metasilicate produced by reaction of the lithium orthosilicate and carbon dioxide is excluded.

2. The absorbent according to claim 1, wherein the lithium metasilicate is contained in an amount of 10% by weight or more to 30% by weight or less with respect to the total amount of lithium orthosilicate and lithium metasilicate.

3. The absorbent according to claim 1, wherein the lithium metasilicate is contained in an amount of 10% by weight or more to 26% by weight or less with respect to the total amount of lithium orthosilicate and lithium metasilicate.

4. The absorbent according to claim 1, further comprising at least one alkali-based compound selected from the group consisting of alkali carbonates, alkali earth carbonates, and alkali halides.

5. The absorbent according to claim 4, wherein the alkali-based compound is contained in an amount of 0.5 to 20 mol % with respect to the total amount of lithium orthosilicate, lithium metasilicate and alkali-based compound.

6. The absorbent according to claim 4, wherein a molar ratio of the lithium metasilicate with respect to the alkali-based compound is 0.04 to 0.35.

7. The absorbent according to claim 1, wherein the absorbent is a porous.

8. A carbon dioxide separating apparatus comprising:

a reaction vessel provided with introduction and discharge pipes for carbon dioxide;

a carbon dioxide absorbent stored in the reaction vessel, including lithium silicate containing lithium orthosilicate and lithium metasilicate, the lithium metasilicate being contained in an amount of 5% by weight or more to 40% by weight or less with respect to the total amount of lithium orthosilicate and lithium metasilicate, where the lithium metasilicate produced by reaction of the lithium orthosilicate and carbon dioxide is excluded; and

heating means disposed around the outer circumference of the reaction vessel for supplying heat to the reaction vessel.

9. The apparatus according to claim 8, wherein the carbon dioxide absorbent further includes at least one alkali-based compound selected from the group consisting of alkali carbonates, alkali earth carbonates, and alkali halides.

10. The apparatus according to claim 9, wherein the alkali-based compound is contained in an amount of 0.5 to 20 mol % with respect to the total amount of lithium orthosilicate, lithium metasilicate and alkali-based compound.

11. The apparatus according to claim 9, wherein a molar ratio of the lithium metasilicate with respect to the alkali-based compound is 0.04 to 0.35.

12. The apparatus according to claim 8, wherein the carbon dioxide absorbent is a porous.

13. A reformer comprising:

a reaction vessel having an introduction pipe which introduces a raw material gas containing carbon and steam, and a discharge pipe which discharges a produced gas;

a solid catalyst stored in the reaction vessel to promote a reforming reaction;

a carbon dioxide absorbent stored in the reaction vessel, including lithium silicate containing lithium orthosilicate and lithium metasilicate, the lithium metasilicate being contained in an amount of 5% by weight or more to 40% by weight or less with respect to the total amount of lithium orthosilicate and lithium metasilicate, where the lithium metasilicate produced by reaction of the lithium orthosilicate and carbon dioxide is excluded; and

heating means disposed around the outer circumference of the reaction vessel for supplying heat to the reaction vessel.

14. The reformer according to claim 13, wherein the carbon dioxide absorbent further includes at least one alkali-based compound selected from the group consisting of alkali carbonates, alkali earth carbonates, and alkali halides.

15. The reformer according to claim 14, wherein the alkali-based compound is contained in an amount of 0.5 to 20 mol % with respect to the total amount of lithium orthosilicate, lithium metasilicate and alkali-based compound.

16. The reformer according to claim 14, wherein a molar ratio of the lithium metasilicate with respect to the alkali-based compound is 0.04 or more to 0.35.

17. The reformer according to claim 13, wherein the carbon dioxide absorbent is a porous.