Carbonising and/or Activating Carbonaceous Material

• US 20100098615A1
• Filed: 10/04/2007
• Published: 04/22/2010
• Est. Priority Date: 10/09/2006
• Status: Active Grant

• Current Assignee: British American Tobacco Limited (British American Tobacco PLC)
• Original Assignee: British American Tobacco Limited (British American Tobacco PLC)
• Inventors: Place, Roger Nicholas, Giles, Alan Mark, Blackburn, Andrew John, Tennison, Stephen Robert, Tunbridge, Jonathan Robert
• Granted Patent: US 8,501,142 B2
• Time in Patent Office: Days
• US Class Current: 423/445.00R
• CPC Class Codes: C01B 32/318 characterised by the starting materials
• CPC Class Codes: C01B 32/336 characterised by gaseous activating agents
• CPC Class Codes: C01B 32/342 characterised by non-gaseous activating agents
• CPC Class Codes: C01B 32/39 Apparatus for the preparation thereof
• CPC Class Codes: C08F 2/18 Suspension polymerisation
• CPC Class Codes: C10B 47/30 in rotary ovens or retorts
• CPC Class Codes: C10B 53/07 of solid raw materials consisting of synthetic polymeric materials, e.g. tyres waste in general, e.g. household waste C10B53/00; recovery or working-up of waste materials of organic macromolecular compounds or compositions based thereon by dry-heat treatment for obtaining partially depolymerised materials C08J11/10; production of liquid hydrocarbon mixtures from rubber or rubber waste C10G1/10
• CPC Class Codes: C10B 57/12 Applying additives during coking
• CPC Class Codes: F27B 7/162 the projections consisting of separate lifting elements, e.g. lifting shovels
• CPC Class Codes: F27B 7/167 the means comprising partitions
• CPC Class Codes: Y02P 20/143 the feedstock being recycled material, e.g. plastics

Abstract

A method is provided for carbonizing and activating carbonaceous material, which comprises supplying the material to an externally fired rotary kiln maintained at carbonizing and activating temperatures, the kiln having a downward slope to progress the material as it rotates, the kiln having an atmosphere substantially free of oxygen provided by a counter-current of steam or carbon dioxide, and annular weirs being provided at intervals along the kiln to control progress of the material. There may further be provided an externally fired rotary kiln for carbonizing and activating carbonaceous material having a hollow rotary body that has a downward slope towards a discharge end thereof, and which is provided at intervals along its length with annular weirs for controlling progress of the carbonaceous material. In embodiments, there is also provided a process is for producing discrete solid beads of polymeric material e.g. phenolic resin beads having a mesoporous structure, which may be useful as feedstock for the above mentioned carbonization/activation process or which may have other utility e.g. as ion exchange resins. The process may produce resin beads on an industrial scale without aggregates of resin building up speedily and interrupting production. The process comprises the steps of: (a) combining a stream of a polymerizable liquid precursor e.g. a novolac and hexamine as cross-linking agent dissolved in a first polar organic liquid e.g. ethylene glycol with a stream of a liquid suspension medium which is a second non-polar organic liquid with which the liquid precursor is substantially or completely immiscible e.g. transformer oil containing a drying oil; (b) mixing the combined stream to disperse the polymerizable liquid precursor as droplets in the suspension medium e.g. using an in-line static mixer; (c) allowing the droplets to polymerise in a laminar flow of the suspension medium so as to form discrete solid beads that cannot agglomerate; and (d) recovering the beads from the suspension medium. There is also provided apparatus for forming discrete solid beads of polymeric material, said apparatus comprising: a first line for conveying s stream of a polymerizable liquid precursor; a second line for conveying a stream of a dispersion medium with which the polymerizable liquid precursor is substantially or completely immiscible; an in-line mixer configured to receive a combined flow from the first and second lines and to disperse the polymerizable liquid precursor as droplets in the dispersion medium; a vertical polymerization column configured to receive the dispersion medium with the droplets dispersed therein and to permit the polymerizable liquid precursor polymerize while descending the column in a descending flow of polymerization medium; and a vessel at the base of the column for receiving the descending flow of dispersion medium and collecting polymerized solid beads.

Claims

1. A method for carbonizing and/or activating carbonaceous material, comprising:

supplying carbonaceious material to an externally fired rotary kiln maintained at carbonizing and activating temperatures, the kiln having a downward slope to progress the material as it rotates, the kiln having an atmosphere substantially free of oxygen provided by a counter-current of steam or carbon dioxide, and annular weirs being provided at intervals along the kiln to control progress of the material.

2. The method of claim 1, wherein the carbonaceous material comprises material of vegetable origin, wherein the material of vegetable origin comprises char.

3. The method of claim 1, wherein the carbonaceous material comprises resin beads, wherein the resin beads comprise beads of phenolic resin, wherein the beads are mesoporous beads and a resulting activated carbon product has macropores, mesopores and micropores, wherein the resin beads are the product of curing a phenoloc resin in a pore-forming solvent.

7. The method of claim 1, wherein the kiln is provided with 5-10 weirs along its length, wherein the carbonaceous material forms a bed, portions of which are lifted and cascaded through the kiln atmosphere by longitudinally directed angularly spaced lift bars extending between weirs, wherein the lift bars have a height above an internal cylindrical surface of the kiln which is approximately 50% of the height of the weirs, wherein the kiln has an entry region configured to dry or remove solvent from the carbonaceous material, wherein the entry region maintained at not more than 300°

C., wherein superheated steam is introduced at the discharge end of the kiln and flows counter-current to the carbonaceous material to provide the kiln atmosphere, wherein the superheated steam is introduced at about 150°

C., wherein the kiln is configured to provide a residence time for the carbonaceous material of 2-5 hours.

29. The method of claim 1, wherein the carbonaceous material comprises discrete solid beads of polymeric material, wherein production of the polymeric material comprises:

forming a combined stream from a stream of a polymerizable liquid precursor and a stream of a liquid dispersion medium with which the liquid precursor is substantially or completely immiscible;

treating the combined stream so as to disperse the polymerizable liquid precursor as droplets in the dispersion medium;

allowing the droplets to polymerise in a laminar flow of the dispersion medium so as to form discrete solid beads that cannot agglomerate; and

recovering the beads from the dispersion medium, the dispersive treatment time being short compared to the laminar flow polymerization time so that agglomeration of the liquid precursor during dispersive treatment is substantially avoided.

30. The method of claim 29, wherein the stream of polymerizable liquid precursor comprises polymerizable components in solution in a first polar organic liquid, and the liquid dispersion medium comprises a second non-polar organic liquid, the first and second organic liquids being substantially immiscible, wherein the first organic liquid is ethylene glycol or diethylene glycol and the second organic liquid is mineral oil or transformer oil, wherein the volume flow rate of the stream of liquid dispersion medium is 3-10 times that of the polymerizable liquid precursor and the polymerizable liquid precursor is formed by combining and mixing first and second component streams thereof, wherein the first component stream comprises a phenolic nucleophilic component dissolved in a pore former and the second component stream comprises a cross-linking agent dissolved in the pore former, wherein the pore former is ethylene glycol, wherein the phenolic nucleophilic component is a novolac with a molecular weight of less than 1500.

41. The method of claim 30, wherein the cross-linking agent comprises hexamethylenetetramine.

42. The method of claim 30, wherein the cross-linking agent comprises melamine or hydroxymethylated melamine.

43. The method of claim 30 wherein the first and second streams are respectively supplied from first and second vessels by pressurising said vessels.

44. The method of claim 30 wherein the first and second streams are respectively supplied from first and second vessels using non-pulsating pumps.

45. The method of claim 44, wherein the non-pulsating pumps are gear or rotary vane pumps.

46. The method of claim 30 wherein the first and second component streams are mixed in an in-line mixer, wherein the mixing in the in-line mixer is at a temperature greater than or equal to 20°

C. below the laminar flow polymerization temperature where polymerization to give a solid particle is complete in less than 2-4 minutes, wherein the stream of liquid dispersion medium is heated to less than or equal to 10°

C. below the laminar flow polymerization temperature prior to combination with the stream of polymerizable liquid precursor, wherein the combined stream is treated so as to disperse the polymerizable liquid precursor as droplets in the suspension medium within 0.2-5 secs, wherein the combined stream is treated to form droplets which give rise to polymer beads of volume average size in the range 100-1000 μ

m, wherein the combined stream is treated to form droplets that give rise to polymerized beads having a D90/D10 particle size distribution less than or equal to 10, wherein the dispersion treatment is in an in-line mixer, wherein the dispersion treatment is carried out under turbulent conditions or transition turbulent conditions.

58. The method of claim 29, further comprising:

supplying the stream of liquid dispersion medium having the polymerizable liquid precursor dispersed as droplets to a vertical polymerization column having a descending flow of liquid suspension medium, the density of the droplets being greater than the density of the liquid suspension medium, wherein the dispersion medium descends the column in 0.5-1.5 hours, wherein dispersed droplets of mean size ˜

400 μ

m descend the column in an average time of about 1-5 minutes, wherein the polymerized beads from the polymerization column are collected in a collection vessel by sedimentation.

64. The method of claim 58, further comprising:

recycling dispersion medium from which polymerized beads have been recovered by centrifugation;

washing the centrifuged beads with water to remove pore-former; and

vacuum drying the beads to recover pore-forming solvent and recycling the recovered pore-forming solvent for production of hexamine/solvent solution and/or resin/solvent solution.

4-6. -6. (canceled)

8-14. -14. (canceled)

15. An externally fired rotary kiln for carbonizing and activating carbonaceous material having a hollow rotary body that has a downward slope towards a discharge end thereof, and which is provided at intervals along its length with annular weirs for controlling progress of the carbonaceous material.

16. The kiln of claim 15, wherein the hollow rotary body is provided with 5-10 weirs, wherein the hollow rotary body is provided with lift bars between the weirs for agitating the carbonaceous material, lifting portions of the material, and causing lifted material to cascade to the bottom of the kiln through the kiln atmosphere.

18. The kiln of claim 15, further comprising a housing surrounding the body and partitions spaced along the housing and defining with the body independently fired heating zones disposed along the kiln, wherein there are 5-10 heating zones.

17. (canceled)

19-25. -25. (canceled)

26. A rotary furnace comprising a substantially cylindrical heating chamber rotatable about a longitudinal axis, said heating chamber being apportioned internally into a plurality of cross-sectional zones by one or more cross-sectional weirs, and wherein the internal surface of the heating chamber bears a plurality of lifter bars running substantially parallel to the longitudinal axis.

27-28. -28. (canceled)

31-40. -40. (canceled)

47-57. -57. (canceled)

59-63. -63. (canceled)

65-75. -75. (canceled)