HIGHLY ATTRITION RESISTANT AND DRY REGENERABLE SORBENTS FOR CARBON DIOXIDE CAPTURE

• US 20080119356A1
• Filed: 11/27/2007
• Published: 05/22/2008
• Est. Priority Date: 01/04/2005
• Status: Active Grant

• Current Assignee: Korea East-West Power Co., Ltd. (Government of South Korea), Korea Electric Power Corporation (Government of South Korea), Korea Midland Power Company Limited (Government of South Korea), Korea South-East Power Co., Ltd. (Government of South Korea), Korea Western Power Company Limited (Government of South Korea), Korea South Power Company Limited
• Original Assignee: Korea East-West Power Co., Ltd. (Government of South Korea), Korea Electric Power Corporation (Government of South Korea), Korea Midland Power Company Limited (Government of South Korea), Korea South-East Power Co., Ltd. (Government of South Korea), Korea Western Power Company Limited (Government of South Korea), Korea South Power Company Limited
• Inventors: Ryu, Chong-Kul, Oh, Je-Myung, Eom, Tae-Hyoung, Lee, Joong-Beom
• Granted Patent: US 8,110,523 B2
• Time in Patent Office: Days
• US Class Current: 502/400
• CPC Class Codes: B01D 2253/10 Inorganic adsorbents
• CPC Class Codes: B01D 2253/304 Linear dimensions, e.g. particle shape, diameter
• CPC Class Codes: B01D 2253/306 Surface area, e.g. BET-specific surface
• CPC Class Codes: B01D 2253/311 Porosity, e.g. pore volume
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 2259/40088 by heating
• CPC Class Codes: B01D 53/12 according to the "fluidised technique"
• CPC Class Codes: B01J 20/043 Carbonates or bicarbonates, e.g. limestone, dolomite, aragonite
• CPC Class Codes: B01J 20/06 comprising oxides or hydroxides of metals not provided for in group B01J20/04
• CPC Class Codes: B01J 20/08 comprising aluminium oxide or hydroxide; comprising bauxite
• CPC Class Codes: B01J 20/14 Diatomaceous earth
• CPC Class Codes: B01J 20/18 Synthetic zeolitic molecular sieves
• CPC Class Codes: B01J 20/28004 Sorbent size or size distribution, e.g. particle size
• CPC Class Codes: B01J 20/28011 Other properties, e.g. density, crush strength
• CPC Class Codes: B01J 20/28014 characterised by their form
• CPC Class Codes: B01J 20/28019 Spherical, ellipsoidal or cylindrical
• CPC Class Codes: B01J 20/2803 Sorbents comprising a binder, e.g. for forming aggregated, agglomerated or granulated products
• CPC Class Codes: B01J 20/28042 Shaped bodies; Monolithic structures
• CPC Class Codes: B01J 20/28045 Honeycomb or cellular structures; Solid foams or sponges
• CPC Class Codes: B01J 20/28057 Surface area, e.g. B.E.T specific surface area
• CPC Class Codes: B01J 20/28059 : being less than 100 m2/g
• CPC Class Codes: B01J 20/28069 : Pore volume, e.g. total pore volume, mesopore volume, micropore volume
• CPC Class Codes: B01J 20/3021 : Milling, crushing or grinding
• 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 20/3483 : 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: B82Y 30/00 : Nanotechnology for materials or surface science, e.g. nanocomposites
• 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

Abstract

Disclosed herein is a dry regenerable sorbent for carbon dioxide present in fuel gases (syngases and coal gases containing hydrogen and carbon monoxide) produced by the combustion of a fossil fuel in industrial plants, including thermal power generation plants, before being released to the air atmosphere, by a dry regenerable sorbent technology.

The sorbent is prepared in the shape of a semisphere by forming a green body using a spray drying technique such that it has suitable shape and particle size for a fluidized-bed process for CO₂ capture. The sorbent comprises an active component selectively reacting with carbon dioxide present in a gas stream to capture the carbon dioxide, a support necessary to improve the reactivity of the active component and to maintain the shape of the sorbent, and a binder capable of binding the active component to the support to impart sufficient mechanical strength to the sorbent.

Further disclosed is a method for preparing the dry regenerable sorbent which comprises the steps of obtaining a slurry through formulation, mixing, comminution and dispersion of the sorbent raw materials, forming the slurry by spray drying to produce sorbent particles, and calcining the sorbent particles. In the step of obtaining a slurry, there is used organic additives (dispersant, a flow control agent, and an organic binder) necessary to obtain a well-dispersed, stable and free-flowing slurry in which the raw materials are present below a sub-micron level (nanosize). The organic additives are removed and decomposed through the calcining. The use of the hydrophilic and high specific surface area support allows the dry regenerable sorbent to have a high reactivity. The solid active component is used instead of a liquid amine used in a conventional wet carbon dioxide capture technology. In addition, the sorbent can be re-used through continuous sorption and regeneration processes. Furthermore, the sorbent can capture carbon dioxide from a large volume of flue gases discharged from thermal power generation plants in an efficient and economical manner. Therefore, the sorbent minimizes the release of carbon dioxide to the air atmosphere and thus contributes to the prevention of global warming.

Claims

1. A method for preparing a dry regenerable sorbent for carbon dioxide capture from flue gas produced by fossil fuel-fired power plants including industrial boilers before being released to atmosphere or from fuel gas stream such as syngas produced by conversion of fossil fuel (e.g. gasification), by dry regenerable sorbent technology,

wherein the method comprises the steps of:

1) adding solid raw materials of the sorbent to water with stirring to obtain a mixture (or a mixed slurry);

2) wet-comminuting and dispersing the mixture to obtain a slurry (i.e. milling and homogenization);

3) forming the slurry using a spray dryer to produce sorbent particles; and

4) pre-drying and calcining the sorbent particles to prepare the final sorbent.

2. The method according to claim 1, further comprising the steps of preparing an aqueous slurry and controlling the concentration of the slurry within the range of 15˜

50 wt %, prior to the step of forming the slurry using a spray dryer.

3. The method according to claim 2, wherein the step of preparing an aqueous slurry includes the sub-steps of:

sequentially or simultaneously adding solid raw materials to water with stirring using a mixer or homogenizer;

adding a dispersant to the mixture such that the solid raw materials are well mixed with and dispersed in the water without agglomeration; and

adding a defoamer to the mixture to remove bubbles or prevent the formation of bubbles during the stirring and homogenization.

4. The method according to claim 3, wherein the mixer or homogenizer has a speed of 50 rpm˜

30,000 rpm, and is at least one machine selected from mechanical stirrers, double-helix mixers, modular homogenizers, blenders, and ultrasonic homogenizers.

5. The method according to claim 3, wherein the dispersant contains a flow control agent;

is at least one surfactant selected from nonionic and anionic surfactants compatible with water; and

is added in an amount of 0.01˜

10 wt %, based on the total weight of the solid raw materials.

6. The method according to claim 3, wherein the defoamer is at least one material selected from silica/silicons, silicons, metallic soaps, amido, polyethers, polyesters, polyglycols, organic phosphates, higher alcohols, and sulfuric acid fats;

and is added in an amount of 0.001˜

1 wt %, based on the total weight of the solid raw materials of the sorbent, in order to inhibit the formation of bubbles by the use of the dispersant or by stirring or to break the bubbles.

7. The method according to claim 3, wherein the mixed slurry (or mixture) is wet-comminuted or milled using at least one mill selected from roller mills, ball mills, attrition mills, vibratory mills, planetary mills and bead mills, and homogenized to obtain a well-dispersed colloidal slurry.

8. The method according to claim 7, wherein the mixed slurry is wet-comminuted using a high-energy bead mill so as to allow the solid raw materials to have an average particle size of 1 μ

m or less, and dispersed to obtain a well-dispersed and uniform colloidal slurry.

9. The method according to claim 8, further comprising the step of adding 0.5˜

5 wt % of an organic binder to the colloidal slurry, based on the total weight of the solid raw materials of the sorbent.

10. The method according to claim 9, wherein the organic binder is at least one binder selected from polyvinyl alcohols, polyethyleneglycols, and methylcelluloses.

11. The method according to claim 9, further comprising the steps of adding a dispersant containing a flow control agent or water to control the flowability and concentration of the slurry, and adding a defoamer to the slurry.

12. The method according to claim 9, further comprising the step of removing (sieving) impurity impeding the dispersion and stability of the slurry and obstructing or plugging the spray of slurry from a nozzle or an atomizer during spray drying step, before the final step of slurry preparation or just before the step of spray drying.

13. The method according to claim 12, further comprising the step of aging the slurry for better dispersion, homogeneity and stability of the slurry, before or after the sieving step.

14. The method according to claim 12, wherein the slurry free of impurity is transferred to a spray drier and spray-dried through a nozzle or an atomizer to form a green body.

15. The method according to claim 14, further comprising the steps of pre-drying the spray-dried green body in a dryer and calcining the pre-dried green body.

16. The method according to claim 15, wherein the pre-drying is carried out at 110˜

150°

C. and the calcination is carried out at 350˜

900°

C.

17. The method according to claim 15 or 16, wherein the spray-dried or pre-dried green body is used as a raw material to prepare a sorbent in the shape of granule, extruding, pellet or honeycomb