Regenerable sorbents for CO2 capture from moderate and high temperature gas streams

• US 7,314,847 B1
• Filed: 10/21/2004
• Issued: 01/01/2008
• Est. Priority Date: 10/21/2004
• Status: Expired due to Fees

• Current Assignee: United States Department of Energy (Government of the United States of America)
• Original Assignee: United States Department of Energy (Government of the United States of America)
• Inventors: Siriwardane, Ranjani V.
• Primary Examiner(s): Vanoy; Timothy C.
• Application Number:
  US10/969,674
• Time in Patent Office: 1,167 Days
• Field of Search: 502/400, 502/411, 502/427, 502/514, 502/518, 502/410, 951/39, 423/230
• US Class Current: 502/400
• CPC Class Codes: B01J 20/041 Oxides or hydroxides
• CPC Class Codes: B01J 20/06 comprising oxides or hydroxides of metals not provided for in group B01J20/04
• CPC Class Codes: B01J 20/10 comprising silica or silicate
• CPC Class Codes: B01J 20/2803 Sorbents comprising a binder, e.g. for forming aggregated, agglomerated or granulated products
• CPC Class Codes: B01J 20/2805 Sorbents inside a permeable or porous casing, e.g. inside a container, bag or membrane
• CPC Class Codes: B01J 20/3042 Use of binding agents; addition of materials ameliorating the mechanical properties of the produced sorbent
• CPC Class Codes: B01J 20/3078 Thermal treatment, e.g. calcining or pyrolizing
• CPC Class Codes: B01J 20/3433 of sorbents or filter aids other than those covered by B01J20/3408 - B01J20/3425
• 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 2220/42 Materials comprising a mixture of inorganic materials materials coated or impregnated on a carrier B01J20/32
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y10S 502/514 Process applicable either to preparing or to regenerating or to rehabilitating catalyst or sorbent
• CPC Class Codes: Y10S 502/518 Carbonaceous contaminant

Abstract

A process for making a granular sorbent to capture carbon dioxide from gas streams comprising homogeneously mixing an alkali metal oxide, alkali metal hydroxide, alkaline earth metal oxide, alkaline earth metal hydroxide, alkali titanate, alkali zirconate, alkali silicate and combinations thereof with a binder selected from the group consisting of sodium ortho silicate, calcium sulfate dihydrate (CaSO₄.2H₂O), alkali silicates, calcium aluminate, bentonite, inorganic clays and organic clays and combinations thereof and water; drying the mixture and placing the sorbent in a container permeable to a gas stream.

Claims

1. A process for producing sorbents to capture carbon dioxide from gas streams, the process comprising:

a) homogeneously mixing a reactive substrate selected from the group consisting of an alkali metal oxide, alkali metal hydroxide, alkaline earth metal oxide, alkaline earth metal hydroxide, alkali titanate, alkali zirconate, alkali silicate and combinations thereof with a binder;

b) adding water to the mixture to form granules;

c) drying the mixture at 100°

C. for 1 hour;

d) calcining the mixture at 700°

C. for 2 hours; and

,

e) placing the mixture in a container permeable to a gas stream to remove carbon dioxide.

2. The process as recited in claim 1 wherein the alkali metal contains a Group I element selected from the group consisting of lithium, sodium, potassium, rubidium, and cesium.

3. The process as recited in claim 1 wherein the binder is a temperature resistant material selected from the group consisting of sodium ortho silicate, calcium sulfate dihydrate (CaSO₄.2H₂O), alkali silicates, calcium aluminate, bentonite, inorganic clays and organic clays.

4. The process as recited in claim 1 wherein the binder facilitates

rehydroxylation of the alkali or alkaline earth compounds during regeneration thereby yielding higher capture capacities in subsequent absorption cycles.

5. The process as recited in claim 1 wherein the reactive substrate facilitates sequestration of carbon dioxide at temperatures ranging from 25°

C. to 600°

C.