HIGH SURFACE AREA CARBON AND PROCESS FOR ITS PRODUCTION

• US 20120094828A1
• Filed: 10/21/2011
• Published: 04/19/2012
• Est. Priority Date: 11/08/2006
• Status: Active Grant

• Current Assignee: Curators of the University of Missouri (University of Missouri)
• Original Assignee: Curators of the University of Missouri (University of Missouri)
• Inventors: Pfeifer, Peter, Suppes, Galen J., Shah, Parag, Burress, Jacob W.
• Granted Patent: US 8,691,177 B2
• Time in Patent Office: Days
• US Class Current: 502/420
• CPC Class Codes: B01J 20/00 Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
• CPC Class Codes: B01J 20/20 comprising free carbon; comprising carbon obtained by carbonising processes
• CPC Class Codes: B01J 20/28057 Surface area, e.g. B.E.T specific surface area
• CPC Class Codes: B01J 20/28083 being in the range 2-50 nm, i.e. mesopores
• CPC Class Codes: B01J 20/28085 being more than 50 nm, i.e. macropores
• CPC Class Codes: B01J 20/3064 Addition of pore forming agents, e.g. pore inducing or porogenic agents
• CPC Class Codes: B01J 21/18 Carbon
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01B 3/0021 Carbon, e.g. active carbon, carbon nanotubes, fullerenes; Treatment thereof
• CPC Class Codes: C01B 32/30 Active carbon
• CPC Class Codes: C01B 32/318 characterised by the starting materials
• CPC Class Codes: C01B 32/342 characterised by non-gaseous activating agents
• CPC Class Codes: C04B 2111/00853 in electrochemical cells or batteries, e.g. fuel cells
• CPC Class Codes: C04B 2111/00948 for the fabrication of containers
• CPC Class Codes: C04B 35/52 based on carbon, e.g. graphite
• CPC Class Codes: C04B 38/0022 obtained by a chemical conversion or reaction other than those relating to the setting or hardening of cement-like material or to the formation of a sol or a gel, e.g. by carbonising or pyrolysing preformed cellular materials based on polymers, organo-metallic or organo-silicon precursors
• CPC Class Codes: C04B 38/0054 the pores being microsized or nanosized
• CPC Class Codes: C10L 3/10 Working-up natural gas or synthetic natural gas
• CPC Class Codes: F17C 11/005 for hydrogen
• CPC Class Codes: F17C 11/007 for hydrocarbon gases, such as methane or natural gas, propane, butane or mixtures thereof [LPG]
• CPC Class Codes: H01G 11/24 : characterised by structural features of the materials making up or comprised in the electrodes, e.g. form, surface area or porosity; characterised by the structural features of powders or particles used therefor
• CPC Class Codes: H01G 11/34 : characterised by carbonisation or activation of carbon
• CPC Class Codes: H01M 4/926 : on carbon or graphite
• CPC Class Codes: H01M 8/04216 : characterised by the choice for a specific material, e.g. carbon, hydride, absorbent
• CPC Class Codes: Y02E 60/13 : Energy storage using capacitors
• CPC Class Codes: Y02E 60/32 : Hydrogen storage
• CPC Class Codes: Y02E 60/50 : Fuel cells
• CPC Class Codes: Y02P 20/145 : the feedstock being materials of biological origin
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries

Abstract

The present invention provides a high surface area porous carbon material and a process for making this material. In particular, the carbon material is derived from biomass and has large mesopore and micropore surfaces that promote improved adsorption of materials and gas storage capabilities.

Claims

1. An activated carbon adsorbent comprising a plurality of particles, wherein each particle has an overall particle size of at least 100 mesh and a total porosity of at least about 70%.

2. The adsorbent of claim 1, further comprising pores with diameters ranging from about 10 Å

to about 20 Å

, wherein greater than about 30% of a total pore volume consists of the pores with diameters ranging from about 10 Å

to about 20 Å

.

3. The adsorbent of claim 2, further comprising a methane gravimetric storage capacity of greater than about 200 g/kg at a temperature of about 20°

C. and a pressure of about 500 psig.

4. The adsorbent of claim 2, further comprising a methane volumetric storage capacity of greater than about 175 V/V at a temperature of about 20°

C. and a pressure of about 500 psig.

5. A process for making an activated carbon adsorbent, the process comprising:

contacting a biomass feed stock with an acidic solution to form an acid soak having a mass ratio of acid solution;

biomass ranging from about 0.2;

1 to about 1.5;

1, wherein the acidic solution comprises an acid in water at an acid concentration ranging from about 50% to about 70% by mass;

maintaining the acid soak at a temperature ranging from about 30°

C. to about 75°

C. for a soak time ranging from about 8 hours to about 14 hours to form an acid-treated biomass;

forming a char by heating the acid-treated biomass to a char temperature ranging from about 400°

C. to about 600°

C. at a heating rate of less than about 2°

C. per minute, maintaining the char temperature for a char time ranging from about 0.5 hours to about 3 hours, cooling the char to room temperature at a rate of less than about 2°

C. per minute, and rinsing the char;

forming an aqueous slurry by contacting the char with an amount of an alkaline material having a pH greater than about 9, wherein the slurry has a mass ratio of alkaline material;

char ranging from about 1;

1 to about 5;

1; and

forming the adsorbent by heating the aqueous slurry to an activation temperature ranging from about 600°

C. to about 1000°

C. in the absence of oxygen, maintaining the activation temperature for an activating time ranging from about 0.1 hours to about 3 hours, cooling the slurry to room temperature at a cooling rate of less than rate of less than about 2°

C. per minute, and rinsing the activated carbon.

6. The process of claim 5, wherein the alkaline material is a metallic hydroxide selected from the group consisting of potassium hydroxide, sodium hydroxide, lithium hydroxide, and beryllium hydroxide.

7. The process of claim 5, wherein the acidic solution is phosphoric acid and the mass ratio of phosphoric acid:

biomass ranges from about 0.5;

1 to about 1;

1.

8. The process of claim 5, wherein the adsorbent comprises a plurality of particles, wherein each particle has an overall particle size of at least 100 mesh and a total porosity of at least about 70%.

9. The process of claim 8, wherein the adsorbent further comprises a methane gravimetric storage capacity of greater than about 200 g/kg at a temperature of about 20°

C. and a pressure of about 500 psig.

10. The process of claim 8, wherein the adsorbent further comprises a methane volumetric storage capacity of greater than about 175 V/V at a temperature of about 20°

C. and a pressure of about 500 psig.

11. The process of claim 5 further comprising pressing the activated carbon with a binder at a temperature ranging from about 130°

C. to about 180°

C. at a pressure ranging from about 13000 psi to about 17000 psi to form a briquette; and

heating the briquette at a temperature ranging from about 600°

C. to about 1200°

C.

12. A method of adsorbing a gas onto an activated carbon adsorbent comprising contacting the adsorbent with the gas in a pressurized container, wherein the adsorbent comprises an overall particle size of at least 100 mesh and a total porosity of at least about 70%.

13. The method of claim 12, wherein the gas comprises a gas species chosen from methane, hydrogen, helium, oxygen, carbon dioxide, nitrogen, acetylene, and combinations thereof, and wherein the pressurized container is chosen from a gas storage tank, a gas separator, a gas treatment tank, and a volatile organic compound removal chamber.

14. The method of claim 13, wherein the gas is methane, the storage tank is a gas storage tank, and wherein the adsorbent further comprises a gravimetric methane storage capacity of greater than about 200 g/kg at a temperature of about 20°

C. and a pressure of about 500 psig.

15. The method of claim 13, wherein the gas is methane, the storage tank is a gas storage tank, and wherein the adsorbent further comprises a volumetric methane storage capacity of greater than about 175 V/V at a temperature of about 20°

C. and a pressure of about 500 psig.