System and method for producing substitute natural gas from coal

• US 8,236,072 B2
• Filed: 02/08/2007
• Issued: 08/07/2012
• Est. Priority Date: 02/08/2007
• Status: Expired due to Fees

• Current Assignee: Arizona Public Service Company (Pinnacle West Capital Corporation)
• Original Assignee: Arizona Public Service Company (Pinnacle West Capital Corporation)
• Inventors: Hobbs, Raymond
• Primary Examiner(s): Johnson, Jonathan
• Assistant Examiner(s): Akram, Imran
• Application Number:
  US11/672,699
• Publication Number:
  US 20080190024A1
• Time in Patent Office: 2,007 Days
• Field of Search: 48/76, 482/08, 482/02
• US Class Current: 48/77
• CPC Class Codes: C01B 2203/0405 Purification by membrane separation
• CPC Class Codes: C01B 2203/042 Purification by adsorption on solids
• CPC Class Codes: C01B 2203/0445 Selective methanation
• CPC Class Codes: C01B 2203/0465 Composition of the impurity
• CPC Class Codes: C01B 2203/047 the impurity being carbon monoxide
• CPC Class Codes: C01B 2203/0475 the impurity being carbon dioxide
• CPC Class Codes: C01B 2203/048 the impurity being an organic compound
• CPC Class Codes: C01B 2203/0485 the impurity being a sulfur compound
• CPC Class Codes: C01B 2203/0495 the impurity being water
• CPC Class Codes: C01B 3/501 by diffusion
• CPC Class Codes: C01B 3/56 by contacting with solids; Regeneration of used solids C01B3/508 takes precedence
• CPC Class Codes: C01B 3/586 the reaction being a methanation reaction
• CPC Class Codes: C10G 2300/1014 of vegetal origin
• CPC Class Codes: C10G 2300/202 Heteroatoms content, i.e. S, N, O, P
• CPC Class Codes: C10G 2300/205 Metal content
• CPC Class Codes: C10G 2300/4043 Limiting CO2 emissions
• CPC Class Codes: C10G 2300/405 Limiting CO, NOx or SOx emissions
• CPC Class Codes: C10G 27/04 with oxygen or compounds generating oxygen
• CPC Class Codes: C10G 3/50 in the presence of hydrogen, hydrogen donors or hydrogen generating compounds
• CPC Class Codes: C10J 2300/093 Coal
• CPC Class Codes: C10J 2300/094 : Char
• CPC Class Codes: C10J 2300/0959 : Oxygen
• CPC Class Codes: C10J 2300/0966 : Hydrogen
• CPC Class Codes: C10J 2300/0969 : Carbon dioxide
• CPC Class Codes: C10J 2300/1606 : Combustion processes
• CPC Class Codes: C10J 2300/1637 : Char combustion
• CPC Class Codes: C10J 2300/1662 : to methane
• CPC Class Codes: C10J 2300/1671 : with the production of electricity
• CPC Class Codes: C10J 2300/1675 : making use of a steam turbine
• CPC Class Codes: C10J 2300/1681 : with biological plants, e.g. involving bacteria, algae, fungi
• CPC Class Codes: C10J 2300/1684 : with electrolysis of water
• CPC Class Codes: C10J 2300/1687 : with steam generation
• CPC Class Codes: C10J 2300/1693 : with storage facilities for intermediate, feed and/or product
• CPC Class Codes: C10J 2300/1807 : Recycle loops, e.g. gas, solids, heating medium, water
• CPC Class Codes: C10J 3/466 : Entrained flow processes
• CPC Class Codes: C10J 3/485 : Entrained flow gasifiers
• CPC Class Codes: C10J 3/84 : with means for removing dust or tar from the gas
• CPC Class Codes: C10K 1/004 : Sulfur containing contaminants, e.g. hydrogen sulfide
• CPC Class Codes: C10K 1/02 : Dust removal
• CPC Class Codes: C10L 3/08 : Production of synthetic natural gas
• CPC Class Codes: C10L 3/10 : Working-up natural gas or synthetic natural gas
• CPC Class Codes: C10L 3/102 : of acid contaminants
• CPC Class Codes: C10L 5/44 : on vegetable substances
• CPC Class Codes: C25B 1/04 : by electrolysis of water
• CPC Class Codes: C25B 9/05 : Pressure cells
• CPC Class Codes: Y02E 50/10 : Biofuels, e.g. bio-diesel
• CPC Class Codes: Y02E 50/30 : Fuel from waste, e.g. synthetic alcohol or diesel
• CPC Class Codes: Y02E 60/36 : Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
• CPC Class Codes: Y02P 30/00 : Technologies relating to oil refining and petrochemical industry
• CPC Class Codes: Y02P 30/20 : using bio-feedstock

Abstract

The present invention provides a system and method for producing substitute natural gas and electricity, while mitigating production of any greenhouse gasses. The system includes a hydrogasification reactor, to form a gas stream including natural gas and a char stream, and an oxygen burner to combust the char material to form carbon oxides. The system also includes an algae farm to convert the carbon oxides to hydrocarbon material and oxygen.

Claims

1. A system for producing substitute natural gas and electricity, the system comprising:

a hydrogasification reactor for reacting hydrogen with coal;

a gas product stream comprising methane in fluid communication with the hydrogasification reactor;

an ash stream in communication with the hydrogasification reactor;

an electrolysis reactor;

a hydrogen source coupled to the hydrogasification reactor and the electrolysis reactor;

a coal source coupled to the hydrogasification reactor;

an oxygen burner, to react the ash stream with oxygen, coupled to an outlet of the hydrogasification reactor;

an oxygen source coupled to the oxygen burner and the hydrogasification reactor;

and an algae farm coupled to an output of the oxygen burner.

2. The system for producing substitute natural gas and electricity of claim 1, wherein the algae farm includes material to convert carbon oxides from the oxygen burner to hydrocarbon material and oxygen.

3. The system for producing substitute natural gas and electricity of claim 2, wherein the hydrocarbon material provides fuel to the oxygen burner.

4. The system for producing substitute natural gas and electricity of claim 3 wherein the electrolysis reactor provides hydrogen to the hydrogen source and oxygen to the oxygen source.

5. The system for producing substitute natural gas and electricity of claim 1, wherein oxygen is reacted with hydrogen in the hydrogasification reactor to produce an operating temperature between about 1600°

F. and 1750°

F.

6. The system for producing substitute natural gas and electricity of claim 1, further comprising a steam boiler coupled to the oxygen burner.

7. The system for producing substitute natural gas and electricity of claim 6, further comprising a steam turbine coupled to the steam boiler.

8. The system for producing substitute natural gas and electricity of claim 1, further comprising an ash removal unit, coupled to the hydrogasification reactor, to remove residual ash from the gas stream.

9. The system for producing substitute natural gas and electricity of claim 8, further comprising a sulfur removal unit, coupled to the ash removal unit, to remove sulfur from the gas stream.

10. The system for producing substitute natural gas and electricity of claim 9, further comprising a methanization reactor, coupled to the sulfur removal unit, to convert residual gases in the gas stream to methane.

11. The system for producing substitute natural gas and electricity of claim 1, further comprising a first char hopper coupled to an outlet of the hydrogasification reactor.

12. The system for producing substitute natural gas and electricity of claim 11, further comprising a second char hopper coupled to the first char hopper and the oxygen burner.

13. The system for producing substitute natural gas and electricity of claim 10, further comprising a cleanup unit, coupled to the methanization reactor, to remove excess hydrogen from the gas stream.

14. A system for producing substitute natural gas arid electricity, the system comprising:

a hydrogasification reactor for reacting hydrogen with coal;

a gas product stream comprising methane in fluid communication with the hydrogasification reactor;

an ash stream in communication with the hydrogasification reactor;

an electrolysis reactor;

a hydrogen source coupled to the hydrogasification reactor and the electrolysis reactor;

a coal source coupled to the hydrogasification reactor;

an oxygen burner, to react the ash stream with oxygen, coupled to an outlet of the hydrogasification reactor;

an oxygen source coupled to the oxygen burner and the hydrogasification reactor;

an algae farm coupled to an output of the oxygen burner;

a steam boiler coupled to the oxygen burner;

a steam turbine coupled to the steam boiler;

an ash removal unit, coupled to the hydrogasification reactor, to remove residual ash from the gas stream;

a sulfur removal unit coupled to the ash removal unit, to remove sulfur from the gas stream; and

a methanization reactor, coupled to the sulfur removal unit, to convert residual gases in the gas stream to methane.

15. The system for producing substitute natural gas and electricity of claim 14, further comprising a first char hopper coupled to an outlet of the hydrogasification reactor.

16. The system for producing substitute natural gas and electricity of claim 14, further comprising a second char hopper coupled to the first char hopper and the oxygen burner.

17. The system for producing substitute natural gas and electricity of claim 14, further comprising a cleanup unit, coupled to the methanization reactor, to remove excess hydrogen from the gas stream.