Carbon dioxide absorbent for exhaust gas, and preparation method thereof

• US 9,138,682 B2
• Filed: 10/30/2009
• Issued: 09/22/2015
• Est. Priority Date: 10/30/2009
• Status: Active Grant

• Current Assignee: Korea Electric Power Corporation (Government of South Korea)
• Original Assignee: Korea Electric Power Corporation (Government of South Korea)
• Inventors: Lee, Joong-Beom, Ryu, Chong-Kul, Jeon, Won-Sik, Baek, Jeom-In, Eom, Tae-Hyeong
• Primary Examiner(s): ANTHONY, JOSEPH DAVID
• Application Number:
  US13/505,151
• Publication Number:
  US 20120273720A1
• Time in Patent Office: 2,153 Days
• US Class Current: 1/1
• CPC Class Codes: B01D 2251/306 of potassium
• CPC Class Codes: B01D 2251/606 Carbonates
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: B01J 20/043 Carbonates or bicarbonates, e.g. limestone, dolomite, aragonite
• CPC Class Codes: B01J 20/08 comprising aluminium oxide or hydroxide; comprising bauxite
• CPC Class Codes: B01J 20/2803 Sorbents comprising a binder, e.g. for forming aggregated, agglomerated or granulated products
• CPC Class Codes: B01J 20/28061 being in the range 100-500 m2/g
• CPC Class Codes: B01J 20/3021 Milling, crushing or grinding
• CPC Class Codes: B01J 20/305 Addition of material, later completely removed, e.g. as result of heat treatment, leaching or washing, e.g. for forming pores
• CPC Class Codes: B01J 20/3078 Thermal treatment, e.g. calcining or pyrolizing
• CPC Class Codes: B01J 20/3204 Inorganic carriers, supports or substrates
• CPC Class Codes: B01J 20/3236 containing metal, other than zeolites, e.g. oxides, hydroxides, sulphides or salts
• CPC Class Codes: B01J 20/3433 of sorbents or filter aids other than those covered by B01J20/3408 - B01J20/3425
• CPC Class Codes: B01J 20/3483 by thermal treatment not covered by groups B01J20/3441 - B01J20/3475, e.g. by heating or cooling
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

A CO₂ absorbent for exhaust gas capable of being repeatedly used in capturing and recycling of CO₂ is provided. The CO₂ absorbent for exhaust gas capturing CO₂ included in exhaust gas is composed of solid materials including an active component at 5 to 70 wt %, a support at 5 to 70 wt %, an inorganic binder at 5 to 70 wt % and a recycling improver at 5 to 70 wt %. The CO₂ absorbent for exhaust gas having such a composition meets the requirements for processes, including physical properties such as a spherical shape, an average particle size and size distribution, a tap density and attrition resistance, and has excellent CO₂ absorbing capability and recycling capability.

The carbon dioxide absorbent for exhaust gas satisfies physical characteristics such as spherical shape, average particle size and size distribution, tap density, attrition resistance and the like required for processes, and has excellent CO₂ absorption and recycling capabilities.

Claims

1. A method of preparing a CO₂ absorbent for exhaust gas, comprising:

preparing a slurry using solid materials comprising an active component at 5 to 70 wt %, a support at 5 to 70 wt %, an inorganic binder at 5 to 70 wt % and a recycling improver at 5 to 70 wt %, based on the total weight of the slurry;

primarily preparing an absorbent by drying the prepared slurry in a spray drier; and

preparing a final absorbent by drying and calcinating the primarily prepared absorbent,

wherein the active component is potassium carbonate or potassium bicarbonate,

wherein the support is alumina,

wherein the inorganic binder is cement, clay, or ceramic,

wherein the recycling improver is hydrotalcite, and

wherein the absorbent material molded in the preparation of the final absorbent has a recycling capability of 70 to 100%.

2. The method of claim 1, wherein preparing the slurry comprises:

forming a mixture by mixing the solid materials in water;

adding a dispersing agent, a defoaming agent, an organic binder or a pH controller to the mixture;

stirring the mixture; and

comminuting and homogenizing the solid materials.

3. The method of claim 2, wherein the slurry has a concentration (a weight ratio of water to the solid materials) of 20 to 50 wt %.

4. The method of claim 2, wherein the solid materials are stirred at a speed of 10,000 to 25,000 rpm using a stirrer including a general stirrer, a double-helix stirrer, a high speed emulsifier, a high shear blender or an ultrasonic emulsifier.

5. The method of claim 2, wherein the solid materials are comminuted using a comminutor including a roller mill, a ball mill, an attrition mill, a planetary mill or a bead mill, and the solid materials are comminuted to a size of larger than 0 to 1 μ

m or less.

6. The method of claim 2, wherein the dispersing agent is an anionic dispersing agent, a cationic dispersing agent, an amphoteric dispersing agent, a non-ionic dispersing agent or a composite thereof, and is added at 0.1 to 10 wt % based on the total weight of the solid materials.

7. The method of claim 2, wherein the defoaming agent is a metal soap- or polyester-based material, and added at 0.01 to 0.2 wt % based on the total weight of the solid materials.

8. The method of claim 2, wherein the organic binder is a polyvinylalcohol- or polyglycol-based material, methylcellulose or a composite thereof, and added at 0.5 to 5 wt % of the total weight of the solid materials.

9. The method of claim 1, wherein preparing the slurry comprises the removal of foreign substances included in the slurry.

10. The method of claim 9, wherein the foreign substances are removed through vacuum sieving.

11. The method of claim 1, wherein, during the primary preparation of the absorbent, an injection pressure of the spray drier is 5 to 15 kg/cm², an inner diameter of a centrifugal pressure nozzle is 0.5 to 1.2 mm, an inlet temperature of the drier is 260 to 300°

C., and an outlet temperature of the drier is 110 to 130°

C.

12. The method of claim 1, wherein preparing the final absorbent comprises drying the primarily prepared absorbent in a reflux drier in an atmosphere at 110 to 150°

C., and heating the dried absorbent in an atmosphere at a speed of 2 to 5°

C./min to calcinate the absorbent at a temperature of 350 to 1000°

C.

13. The method of claim 12, wherein the absorbent molded in the preparation of the final absorbent has a spherical shape, a particle size of 60 to 180 μ

m, a particle distribution of 30 to 400 μ

m, a tap density of 0.6 to 1.2 g/cc, an attrition resistance of 0.01 to 30%, and a CO₂ absorbing capability of 3 to 10 wt %.