Catalyst-Loaded Coal Compositions, Methods of Making and Use

• US 20090048476A1
• Filed: 07/23/2008
• Published: 02/19/2009
• Est. Priority Date: 08/02/2007
• Status: Active Grant

• Current Assignee: Sure Champion Investments Limited
• Original Assignee: GreatPoint Energy, Inc.
• Inventors: Rappas, Alkis S., Hippo, Edwin J., Salem, George Frederick
• Granted Patent: US 8,163,048 B2
• Time in Patent Office: Days
• US Class Current: 585/701
• CPC Class Codes: B01J 21/18 Carbon
• CPC Class Codes: B01J 23/02 of the alkali- or alkaline earth metals or beryllium
• CPC Class Codes: B01J 38/48 Liquid treating or treating in liquid phase, e.g. dissolved or suspended
• CPC Class Codes: C10J 2300/0906 Physical processes, e.g. shredding, comminuting, chopping, sorting
• CPC Class Codes: C10J 2300/0909 Drying
• CPC Class Codes: C10J 2300/093 Coal
• CPC Class Codes: C10J 2300/0973 Water
• CPC Class Codes: C10J 2300/0983 Additives
• CPC Class Codes: C10J 2300/1807 Recycle loops, e.g. gas, solids, heating medium, water
• CPC Class Codes: C10J 2300/1823 for synthesis gas
• CPC Class Codes: C10J 3/00 Production of combustible gases containing carbon monoxide from solid carbonaceous fuels destructive distillation processes C10B
• CPC Class Codes: C10J 3/482 Gasifiers with stationary fluidised bed
• CPC Class Codes: C10J 3/54 Gasification of granular or pulverulent fuels by the Winkler technique, i.e. by fluidisation
• CPC Class Codes: C10L 9/08 by heat treatments, e.g. calcining
• CPC Class Codes: C10L 9/10 by using additives
• CPC Class Codes: Y02P 20/10 Process efficiency
• CPC Class Codes: Y02P 20/52 using catalysts, e.g. selective catalysts
• CPC Class Codes: Y02P 20/582 Recycling of unreacted starting or intermediate materials
• CPC Class Codes: Y02P 20/584 Recycling of catalysts

Abstract

The present invention relates to catalyst-loaded coal compositions having a moisture content of less than about 6 wt %, a process for the preparation of catalyst-loaded coal compositions, and an integrated process for the gasification of the catalyst-loaded coal compositions. The catalyst-loaded coal compositions can be prepared by a diffusive catalyst loading process that provides for a highly dispersed catalyst that is predominantly associated with the coal matrix, such as by ion-exchange.

Claims

1. A catalyst-loaded coal composition comprising a coal and a gasification catalyst, wherein (i) the coal comprises a matrix containing ion exchange sites comprising acidic functional groups;

(ii) the composition has a moisture content of less than about 6 wt %;

(iii) the gasification catalyst is an alkali metal cation or mixtures thereof;

(iv) the gasification catalyst is present in an amount such that a ratio of catalyst atoms to carbon atoms is in the range of about 0.01 to about 0.1; and

(v) greater than about 50% of the total amount of the catalyst loaded is associated with the coal matrix by ion exchange on the acidic functional groups of the coal.

2. The composition according to claim 1, having a particle size ranging from about 25 microns to about 2500 microns.

3. The composition according to claim 1, wherein the gasification catalyst is potassium cation, sodium cation, lithium cation or mixtures thereof.

4. The composition according to claim 1, wherein the coal is sub-bituminous, bituminous, lignite, anthracite or mixtures thereof.

5. The composition according to claim 1, wherein the coal is sub-bituminous, the gasification catalyst is potassium cation, and wherein the gasification catalyst is present in an amount such that a ratio of catalyst atoms to carbon atoms is in the range of about 0.03 to about 0.05.

6. The composition according to claim 1, wherein the coal is lignite, the gasification catalyst is potassium cation, and wherein the gasification catalyst is present in an amount such that a ratio of catalyst atoms to carbon atoms is in the range of about 0.03 to about 0.04.

7. The composition according to claim 1, wherein the catalyst is highly dispersed throughout the coal matrix.

8. The composition according to claim 1, wherein greater than about 70% of the total amount of catalyst loaded is associated with the coal matrix.

9. A method of preparing a catalyst-loaded coal composition comprising the steps of:

(a) grinding a raw coal;

(b) soaking the ground coal in an excess of aqueous solution comprising a salt of a catalyst to form a slurry, wherein the slurry is at a density within the range from about 5 wt % to about 40 wt % solids;

(c) holding the slurry at a contact temperature and for a contact time so as to provide ample opportunity to achieve substantial and uniform catalyst loading;

(d) dewatering the slurry to form a catalyst-loaded wet coal cake; and

(e) thermally-treating the catalyst-loaded wet coal cake under a flow of inert dry gas at a temperature and for a time sufficient to reduce the moisture content to less than about 6 wt %.

10. The method according to claim 9, wherein the catalyst is potassium, sodium, lithium or mixtures thereof.

11. The method according to claim 9, wherein the solution further comprises a phosphorous- and boron-free wetting agent.

12. The method according to claim 9, wherein the ground coal prior to step (b) is separated into a first fraction and a second fraction, wherein the first fraction is larger than the second fraction, and wherein the first and second fractions are in a ratio ranging from greater than 50:

50 to 90;

10, and wherein the first fraction is used in steps (b)-(d), and the second fraction is thoroughly mixed with said first fraction after steps (b)-(d) before step (e).

13. The method according to claim 9, wherein the coal prior to step (a) is separated into a first fraction and a second fraction, wherein the first fraction is larger than the second fraction, and wherein the first and second fractions are in a ratio ranging from greater than 50:

50 to 90;

10, and wherein the first fraction is used in steps (a)-(d), and the second fraction is ground, and the ground second fraction is thoroughly mixed with said first fraction after steps (a)-(d) before step (e).

14. The method according to claim 9, wherein the raw coal is sub-bituminous, bituminous, lignite, anthracite or mixtures thereof.

15. The method according to claim 9, wherein the slurry is held at a contact temperature ranging from about 20°

C. to about 95°

C. for a contact time ranging from about 1 hours to about 48 hours.

16. The method according to claim 9, wherein the thermally-treating step is performed at a temperature ranging from about 90°

C. to about 250°

C.

17. The method according to claim 9, wherein the aqueous solution comprises an amount of the catalyst salt sufficient to provide the catalyst-loaded coal composition having a ratio of catalyst atoms to carbon atoms in the range of about 0.01 to about 0.1.

18. The method according to claim 9, wherein the raw coal is sub-bituminous, the catalyst is potassium cation, the salt of said catalyst is potassium carbonate, and the aqueous solution comprises an amount of the catalyst salt sufficient to provide the catalyst-loaded coal composition having a ratio of catalyst atoms to carbon atoms in the range of about 0.03 to about 0.05.

19. The method according to claim 9, wherein the aqueous solution comprises an amount of said catalyst salt equal to or greater than the amount to achieve saturation ion-exchange loading of the coal.

20. A catalyst-loaded coal composition, prepared by the process of claim 9.

21. An integrated process for the steady-state gasification of an optimized reactor feed catalyst-loaded coal composition, comprising the steps of:

(a) providing a ground raw coal solid stream into a diffuse catalyst loading contactor;

(b) introducing an influent stream comprising a salt of a catalyst into the diffuse catalyst loading contactor to create a slurry, wherein the influent stream is comprised of a raffinate stream, a recycle stream and a makeup stream;

(c) controlling the amount of catalyst in the influent stream;

(d) holding the slurry at a contact temperature and for a contact time so as to provide ample opportunity to achieve substantial and uniform catalyst loading;

(e) dewatering the slurry by filtration to form a catalyst-loaded wet coal cake and the raffinate solution;

(f) recycling the raffinate solution into the influent stream;

(g) thermally-treating the catalyst-loaded wet coal cake under a flow of inert dry gas to reduce the moisture content to less than about 6 wt %;

(h) gasifying the catalyst-loaded thermally-treated coal composition in a fluidized bed reactor in the presence of steam and a recycled gas at a temperature ranging from about 450°

C. to about 750°

C. and a pressure ranging from about 50 psig and about 1000 psig, to produce a char and a raw gas stream comprising methane;

(i) withdrawing the raw gas stream from the fluidized bed reactor;

(j) withdrawing the char from the fluidized bed reactor;

(k) extracting catalyst from the char; and

(l) recycling extracted catalyst into the influent stream as the recycle stream.

22. The integrated process according to claim 21, wherein the amount of catalyst in the influent stream is controlled by a method comprising the steps of:

(a) monitoring the amount of catalyst in the raffinate stream;

(b) monitoring the amount of catalyst in the recycle stream; and

(c) adjusting the amount of catalyst in the makeup stream.

23. The integrated process according to claim 21, wherein the concentration of catalyst in the influent stream is sufficient to provide the catalyst-loaded coal composition having a ratio of catalyst atoms to carbon atoms in the range of about 0.01 to about 0.1.

24. The integrated process according to claim 21, wherein the amount of catalyst in the influent stream ranges from about 0.3 mol/kg to about 3.0 mol/kg.

25. The integrated process according to claim 21, wherein the amount of catalyst in the influent stream is equal to or greater than the amount to achieve saturation ion-exchange loading of the coal.

26. The integrated process according to claim 21, wherein the coal is sub-bituminous, bituminous, lignite, anthracite or mixtures thereof.

27. The integrated process according to claim 21, wherein the ground raw coal is sub-bituminous, the catalyst is potassium cation, the salt of said catalyst is potassium carbonate, and the influent solution comprises a concentration of the catalyst salt sufficient to provide the catalyst-loaded coal composition having a ratio of catalyst atoms to carbon atoms in the range of about 0.03 to about 0.05.