CA2731376A1 - Enhancement of fischer-tropsch process for hydrocarbon fuel formulation - Google Patents

Abstract

An enhanced Fischer-Tropsch process for the synthesis of sulfur free, clean burning, green hydrocarbon fuels, examples of which include syndiesel and aviation fuel. Naphtha is destroyed in a hydrogen generator and recycled as feedstock to a syngas (FT) reactor in order to enhance the production of syndiesel from the reactor. A further variation integrates a second hydrogen generator capturing light hydrocarbon gas for conversion to hydrogen and carbon monoxide which supplements the Fischer-Tropsch reactor. The result is a considerable increase in the volume of syndiesel formulated. A system for effecting the process is also characterized in the specification.

Claims (45)

1. A process for synthesing hydrocarbons, comprising the steps of:

(a) formulating a hydrogen lean syngas stream in a non-catalytic partial oxidation reaction;

(b) catalytically converting said syngas stream to produce hydrocarbons, containing at least naphtha;

(c) recycling said naphtha to a hydrogen generator to form a hydrogen rich stream; and (d) combining said hydrogen rich stream with the hydrogen lean stream of step (a) to enhance the conversion of hydrocarbons.

2. The process as set forth in claim 1, wherein said hydrogen lean syngas stream is formed in a thermal gasifier.

3. The process as set forth in claim 2, wherein said gasifier gasifies a member selected from the group consisting of coal, biomass, petroleum resids, petcoke, municipal waste, plastics, wood waste, demetallized tire scrap, forestry waste material, waste water biomass, sewage biomass, agricultural waste, agricultural byproducts, carbonaceous material and mixtures thereof.

4. The process as set forth in any one of claims 1 through 3, wherein catalytic conversion carried out in step (b) is effected using a Fischer-Tropsch reaction.

5. The process as set forth in any one of claims 1 through 4, wherein subsequent to step (b), naphtha is generated in addition to heavier hydrocarbons, light hydrocarbons and a refinery fuel gas.

6. The process as set forth in claim 5, wherein further including the step of separating at least a portion of said naphtha from said heavier and lighter hydrocarbons.

7. The process as set forth in any one of claims 1 through 6, wherein said hydrogen generator in step (c) comprises a steam methane reformer (SMR).

8. The process as set forth in claim 4, wherein said hydrogen rich stream of step (d) is reacted into said Fischer-Tropsch reaction.

9. The process as set forth in any one of claims 1 through 8, further including the step of adding an auxiliary source of hydrogen to said hydrogen generator.

10. The process as set forth in claim 9, wherein said auxiliary source comprises natural gas.

11. The process as set forth in claim 9, wherein said auxiliary source of hydrogen comprises refinery gas.

12. The process as set forth in any one of claims I through 11, wherein converted hydrocarbon comprises at least one of aviation fuel and diesel fuel.

13. The process as set forth in any one of claims 1 through 12, further including a series of unit operations between steps (a) through (d) for optimizing conversion of hydrocarbons.

14. The process as set forth in claim 13, wherein said unit operations at least include cleansing syngas by removal of carbon dioxide prior to synthesis of said hydrocarbons.

15. The process as set forth in claim 14, wherein said syngas cleansing includes at least one of a caustic wash for halide removal, an acid wash for ammonia removal, and an activated charcoal treatment for hydrogen sulfide removal.

16. The process as set forth in claim 14, wherein said carbon dioxide removal includes at least one of drying and compression, and removal of said carbon dioxide as a product.

17. A process for synthesing hydrocarbons, comprising the steps of:

(a) formulating a hydrogen lean syngas stream in a non-catalytic partial oxidation reaction;

(b) catalytically converting said syngas stream to produce a hydrocarbon, containing at least naphtha and fuel gas;

(c) recycling said naphtha to a hydrogen generator to form a hydrogen rich stream;

(d) recycling fuel from step (b) to a second hydrogen generator to form a supplemental syngas stream; and (e) combining said hydrogen rich stream and said supplemental syngas stream with the hydrogen lean stream of step (a) to enhance the conversion of hydrocarbons.

18. The process as set forth in claim 17, wherein said recycled fuel from step (d) comprises refinery gas from the Fischer-Tropsch unit and or hydrocarbon upgrader unit.

19. The process as set forth in claim 17 or 18, wherein said supplemental stream of syngas is formed using an autothermal reformer (ATR).

20. The process as set forth in any one of claims 17 through 19, wherein said hydrogen lean syngas stream is formed in a thermal gasifier.

21. The process as set forth in claim 20, wherein said gasifier gasifies a member selected from the group consisting of coal, biomass, petroleum resids, petcoke, municipal waste, plastics, wood waste, demetallized tire scrap, forestry waste material, waste water biomass, sewage biomass, agricultural waste, agricultural byproducts, carbonaceous material and mixtures thereof.

22. The process as set forth in any one of claims 17 through 21, wherein catalytic conversion carried out in step (b) is effected using a Fischer-Tropsch reaction.

23. The process as set forth in any one of claims 17 through 22, wherein subsequent to step (b), the fraction of naphtha is generated in addition to heavier hydrocarbons.

24. The process as set forth in claim 22, further including the step of separating at least a portion of said heavier hydrocarbons from said naphtha.

25. The process as set forth in any one of claims 17 through 24, wherein said hydrogen generator in step (c) comprises a steam methane reformer (SMR).

26. The process as set forth in any one of claims 17 through 25, wherein the hydrogen rich stream of step (d) is introduced into said Fischer-Tropsch reactor.

27. The process as set forth in any one of claims 17 through 26, further including the step of adding an auxiliary source of hydrogen to said hydrogen generator and second hydrogen generator.

28. The process as set forth in claim 27, wherein said auxiliary source comprises natural gas.

29. The process as set forth in claim 27, wherein said auxiliary source of hydrogen comprises refinery gas.

30. The process as set forth in any one of claims 17 through 29, wherein converted hydrocarbon comprises at least one of aviation fuel and diesel fuel.

31. The process as set forth in any one of claims 17 through 30, further including a series of unit operations between steps (a) through (d) for optimizing said conversion of hydrocarbons.

32. The process as set forth in claim 31, wherein said unit operations at least include cleansing syngas by removal of carbon dioxide prior to synthesis of said hydrocarbons.

33. The process as set forth in claim 32, wherein said syngas cleansing includes at least one of a caustic wash for halide removal, an acid wash for ammonia removal, and an activated charcoal treatment for hydrogen sulfide removal.

34. The process as set forth in claim 33, wherein said carbon dioxide removal includes at least one of drying and compression, and removal of said carbon dioxide as a product.

35. A system for synthesizing hydrocarbons, said system comprising:
(a) means for generating syngas lean in hydrogen content;

(b) means for catalytically converting said syngas to produce hydrocarbons, containing at least naphtha;

(c) a hydrogen generator;

(d) circuit means for recycling naphtha to said hydrogen generator to form a hydrogen rich stream; and (e) circuit means for combining said hydrogen rich stream with said hydrogen lean stream to provide a blended and enriched hydrogen content stream for enhancing hydrocarbon production.

36. The system as set forth in claim 35, wlierein said means for generating syngas comprises a thermal gasifier.

37. The system as set forth in claim 35 or 36, wherein said means for catalytically converting said syngas comprises a Fischer-Tropsch reaction.

38. The system as set forth in any one of claims 35 through 37, wherein said circuit means for recycling naphtha to said hydrogen generator comprises a recycle loop.

39. The system as set forth in any one of claims 35 through 38, wherein said hydrogen generator comprises a member selected from the group consisting of a steam methane reformer and a autothermal reformer or a combination thereof.

40. The system as set forth in any one of claims 35 through 39, wherein said circuit means for recycling naphtha to said hydrogen generator comprises a recycle loop for recycling naphtha into at least one of said SMR, said ATR, or a combination thereof.

41. The system as set forth in any one of claims 35 through 40, wherein said hydrogen generator comprises an SMR and an ATR.

42. The system as set forth in any one of claims 35 through 41, further including means for hydrocracking product exiting said means for catalytically converting said syngas.

43. The system as set forth in any one of claims 35 through 42, further including means for fractionating hydrocracked product.

44. The system as set forth in any one of claims 35 through 43, further including means for withdrawing energy from said system to act as a precursor for power generation.

45. The system as set forth in any one of claims 35 through 44, further including means for storing formulated enhanced hydrocarbon.