RENDERING COAL AS AN ENVIRONMENTALLY CARBON DIOXIDE NEUTRAL FUEL AND A REGENERATIVE CARBON SOURCE

• US 20100261125A1
• Filed: 04/07/2010
• Published: 10/14/2010
• Est. Priority Date: 04/10/2009
• Status: Active Grant

• Current Assignee: University of Southern California
• Original Assignee: University of Southern California
• Inventors: Prakash, G.K. Surya, Olah, George A.
• Granted Patent: US 8,461,215 B2
• Time in Patent Office: Days
• US Class Current: 431/2
• CPC Class Codes: B01J 23/8472 Vanadium
• CPC Class Codes: C01B 2203/0233 the reforming step being a steam reforming step
• CPC Class Codes: C01B 2203/0238 the reforming step being a carbon dioxide reforming step
• CPC Class Codes: C01B 2203/061 Methanol production
• CPC Class Codes: C01B 2203/0827 at least part of the fuel being a recycle stream
• CPC Class Codes: C01B 2203/1041 Composition of the catalyst
• CPC Class Codes: C01B 2203/1047 Group VIII metal catalysts
• CPC Class Codes: C01B 2203/1058 Nickel catalysts
• CPC Class Codes: C01B 2203/1076 Copper or zinc-based catalysts
• CPC Class Codes: C01B 2203/1082 Composition of support materials
• CPC Class Codes: C01B 2203/1241 Natural gas or methane
• CPC Class Codes: C01B 2203/141 At least two reforming, decomposition or partial oxidation steps in parallel
• CPC Class Codes: C01B 2203/148 involving a recycle stream to the feed of the process for making hydrogen or synthesis gas
• CPC Class Codes: C01B 3/38 using catalysts
• CPC Class Codes: C07C 1/20 starting from organic compounds containing only oxygen atoms as heteroatoms
• CPC Class Codes: C07C 11/04 Ethylene
• CPC Class Codes: C07C 11/06 Propene
• CPC Class Codes: C07C 29/1518 one step being the formation of initial mixture of carbon oxides and hydrogen for synthesis
• CPC Class Codes: C07C 31/04 Methanol
• CPC Class Codes: C07C 41/09 by dehydration of compounds containing hydroxy groups
• CPC Class Codes: C07C 43/043 : Dimethyl ether
• CPC Class Codes: Y02P 20/133 : Renewable energy sources, e.g. sunlight
• 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 30/20 : using bio-feedstock
• CPC Class Codes: Y02P 30/40 : Ethylene production

Abstract

The invention provides a method for rendering coal as an environmentally essentially carbon dioxide-neutral fuel. Carbon dioxide produced from coal combustion is captured, purified, combined with coalbed methane or any other natural methane or natural gas source, or with hydrogen, and reacted under reaction conditions sufficient to form methanol and/or dimethyl ether, which can be used as fuel or feedstock for derived synthetic hydrocarbons and products.

Claims

1. A method for rendering coal as an essentially environmentally carbon dioxide-neutral fuel and regenerative carbon source, which comprises:

subjecting coal to reaction conditions sufficient to produce carbon dioxide;

capturing and purifying the produced carbon dioxide; and

combining the purified carbon dioxide with water and a suitable hydrocarbon source or with hydrogen under reaction conditions sufficient to produce methanol or dimethyl ether, so that the carbon dioxide generated from the coal is not introduced into the atmosphere, thus rendering the coal as an essentially environmentally carbon dioxide-neutral fuel.

2. The method of claim 1 which further comprises:

recycling the methanol for use as a fuel or feedstock;

subjecting the methanol fuel or products made from the feedstock to reaction conditions to generate carbon dioxide; and

repeating the capturing, combining, recycling and subjecting steps on the generated carbon dioxide so that the carbon dioxide produced from the methanol fuel or products made from methanol feedstock also is not emitted to the atmosphere.

3. The method of claim 1, wherein the subjecting step generates energy and is performed in a power plant.

4. The method of claim 1, wherein the carbon dioxide, suitable hydrocarbon source, and water are combined in an appropriate molar ratio are reacted in separate steps or in a single step to produce methanol.

5. The method of claim 1, wherein the suitable hydrocarbon source is methane or coalbed methane or natural gas.

6. The method of claim 1, which further comprises:

combusting the coal to produce carbon dioxide;

capturing the produced carbon dioxide on an adsorbent; and

treating the adsorbent to release the captured carbon dioxide therefrom for use in producing methanol or dimethyl ether.

7. The method of claim 6, wherein the adsorbent is treated with sufficient heating, reduced pressure, vacuum, gas purge, or a combination thereof to release the captured carbon dioxide.

8. The method of claim 6, wherein the absorbent is a polyamino-containing polymer deposited on a nano-structured supporting having a high surface area.

9. The method of claim 8, wherein the polyamino-containing polymer is polyethyleneimine and the support is nano-structured fused silica or alumina.

10. The method of claim 1, which further comprises:

reacting carbon dioxide with a suitable hydrocarbon source and steam under steam reforming reaction conditions sufficient to form a mixture of hydrogen and carbon monoxide,

reacting carbon dioxide with a suitable hydrocarbon source under dry reforming reaction conditions sufficient to form a mixture of hydrogen and carbon monoxide, and

combining the hydrogen and carbon monoxide produced in the steam reforming and dry reforming to form a mixture of hydrogen and carbon monoxide in a molar ratio of about 2 moles of hydrogen to 1 mole of carbon monoxide for reaction to form methanol.

11. The method of claim 10, wherein the steam reforming and the dry reforming are performed simultaneously in a single bireforming step.

12. The method of claim 10, wherein the methane, steam and carbon dioxide are reacted in a single step in a molar ratio of about 3:

2;

1 to form a mixture of hydrogen and carbon dioxide in a molar ratio of about 2;

1.

13. The method of claim 10, wherein the steam reforming and the dry reforming are performed simultaneously in a single step over a catalyst at a temperature between about 800°

C. and 1100°

C.

14. The method of claim 13, wherein the catalyst is provided on a support of a high surface area nano-structured fumed alumina or fumed silica.

15. The method of claim 13, wherein the catalyst comprises V, Ti, Ga, Mg, Cu, Ni, Mo, Bi, Fe, Mn, Co, Nb, Zr, La or Sn, or an oxide thereof.

16. The method of claim 13, wherein the catalyst comprises a single metal catalyst, a single metal oxide catalyst, a mixed catalyst of a metal and a metal oxide, or a mixed catalyst of at least one metal oxide and another metal oxide, the catalyst optionally being provided on an oxide support.

17. The method of claim 16, wherein the catalyst is NiO or a mixed catalyst of NiO, V₂O₅:

Ni₂O₃, Ni₂V₂O₇ and Ni₃V₂O₅.

18. The method of claim 16, wherein the catalyst is NiO supported on fumed alumina or NiO/V₂O₅ supported on fumed silica.

19. The method of claim 10, which further comprises dehydrating methanol by removing water under conditions sufficient to produce dimethyl ether and recycling the water from dehydration during subsequent reforming.

20. The method of claim 19, which further comprises reacting the dimethyl ether in the presence of an acidic-basic or zeolitic catalyst under conditions sufficient to form ethylene or propylene.

21. The method of claim 20, which further comprises converting ethylene or propylene under conditions sufficient to produce synthetic hydrocarbons, chemicals, or polymers.

22. The method of claim 1, which further comprises combusting the produced methanol, optionally in a mixture that includes gasoline, in a power plant that produces energy with the combusted methanol while also generating carbon dioxide and recycling the generated carbon dioxide for producing methanol.

23. The method of claim 19, which further comprises combusting the produced dimethyl ether, optionally in a mixture that includes natural gas and liquefied petroleum gas, in a power plant that produces energy while also generating carbon dioxide and recycling the generated carbon dioxide for producing methanol which in turn produces additional dimethyl ether.