Synthetic hydrocarbon products

• US 20060006098A1
• Filed: 07/08/2004
• Published: 01/12/2006
• Est. Priority Date: 07/08/2004
• Status: Active Grant

• Current Assignee: Phillips 66 Company
• Original Assignee: Conocophillips Company (ConocoPhillips)
• Inventors: Espinoza, Rafael L., Lawson, Keith H.
• Granted Patent: US 7,345,211 B2
• Time in Patent Office: Days
• US Class Current: 208/15
• CPC Class Codes: C10G 2400/04 Diesel oil
• CPC Class Codes: C10G 63/04 including at least one cracking step
• CPC Class Codes: C10L 1/08 for compression ignition
• CPC Class Codes: Y10S 208/95 Processing of "fischer-tropsch" crude

Abstract

The invention includes a process for producing synthetic middle distillates and synthetic middle distillates produced therefrom. In one embodiment, the process comprises fractionating a hydrocarbon synthesis product to at least generate a light middle distillate, a heavy middle distillate, and a waxy fraction; thermally cracking the waxy fraction; and isomerizing the heavy middle distillate. A synthetic diesel or blending component is formed by the combination of at least a portion of the light middle distillate; at least a portion or fraction of the thermally cracked product; and at least a portion or fraction of the isomerized product. In some embodiments, the hydrocarbon synthesis product and/or the thermally cracked product may be hydrotreated. In other embodiments, a synthetic middle distillate comprises at least two fractions: a light fraction with not more than 10% branched hydrocarbons, and a heavy fraction with at least 30% branched hydrocarbons.

Claims

1. A process for producing a synthetic diesel, the process comprising:

(A) feeding a syngas to a hydrocarbon synthesis reactor, wherein at least a portion of the syngas is reacted to generate a hydrocarbon synthesis product comprising C₅₊ hydrocarbons;

(B) hydrotreating a hydrocarbon feed comprising the hydrocarbon synthesis product to provide a hydrotreated hydrocarbon stream;

(C) fractionating a fractionator feedstream comprising the hydrotreated hydrocarbon stream to produce a light diesel distillate, a heavy diesel distillate, and a waxy fraction;

(D) thermally cracking at least a portion of the waxy fraction to produce a thermal cracker effluent;

(E) hydrotreating at least a portion or a fraction of the thermal cracker effluent to form a hydrotreated thermal cracker product; and

(F) isomerizing at least a portion of the heavy diesel distillate to produce an isomerized heavy diesel product.

2. The process of claim 1, wherein the hydrocarbon synthesis reactor comprises a Fischer-Tropsch reactor.

3. The process of claim 1, wherein hydrotreating comprises temperatures between about 80°

C. and about 400°

C.

4. The process of claim 1, wherein hydrotreating in steps (B) and (E) comprises temperatures between about 80°

C. and about 250°

C.

5. The process of claim 1, wherein hydrotreating in steps (B) and (E) are performed in different hydrotreaters.

6. The process of claim 1, wherein hydrotreating in steps (B) and (E) are performed in the same hydrotreater.

7. The process of claim 6, further comprising recycling at least a portion of or at least a fraction of the thermal cracker effluent to step (B).

8. The process of claim 1, wherein step (C) further produces a naphtha distillate.

9. The process of claim 1, wherein step (C) further produces a jet fuel.

10. The process of claim 8, wherein the naphtha distillate comprises at least 90 percent linear hydrocarbons.

11. The process of claim 1, wherein the light diesel distillate comprises primarily C₁₀-C₁₆ hydrocarbons, and the heavy diesel distillate comprises primarily C₁₇-C₂₃ hydrocarbons.

12. The process of claim 1, wherein the light diesel distillate is characterized by a 5% boiling point less than about 360°

F. and a 95% boiling point between about 500°

F. and about 550°

F., and the heavy diesel distillate is characterized by a 5% boiling point between about 500°

F. and 550°

F. and a 95% boiling point greater than about 630°

F.

13. The process of claim 1, wherein the thermal cracking occurs between about 380°

C. and about 700°

C.

14. The process of claim 1, wherein the thermal cracking occurs between about 380°

C. and about 550°

C.

15. The process of claim 1, wherein isomerizing the heavy diesel distillate occurs at temperatures between about 180°

C. and about 380°

C.

16. The process of claim 1, wherein step (D) further comprises fractionating the thermal cracker effluent into a light thermally cracked fraction and a heavy thermally cracked fraction;

wherein step (E) comprises hydrotreating said heavy thermally cracked fraction; and

further wherein the light thermally cracked fraction comprises olefins and is not hydrotreated.

17. The process of claim 1, further comprising feeding the hydrotreated thermal cracker product of step (E) to the fractionating step (C).

18. The process of claim 1, further comprising forming a synthetic diesel by blending at least a portion of the light diesel distillate and at least a portion of the isomerized heavy diesel product.

19. The process of claim 18, wherein the synthetic diesel further comprises at least a fraction of the hydrotreated thermal cracker product.

20. The process of claim 1, wherein the synthetic diesel comprises C₁₀-C₁₇ hydrocarbons having at least about 80 percent linear hydrocarbons.

21. The process of claim 19, wherein the synthetic diesel further comprises C₁₇-C₂₃ hydrocarbons having at least about 30 percent isomerized hydrocarbons.

22. The process of claim 21, wherein the diesel comprises C₁₇-C₂₃ hydrocarbons having at least about 40 percent isomerized hydrocarbons.

23. A process for producing diesel, the process comprising:

(A) feeding a syngas to a hydrocarbon synthesis reactor, wherein at least a portion of the syngas is reacted to generate a hydrocarbon synthesis product comprising C₅₊ hydrocarbons;

(B) providing a fractionator feed comprising the hydrocarbon synthesis product;

(C) separating the fractionator feed in a fractionator to produce at least a light diesel distillate, a heavy diesel distillate, and a waxy fraction;

(D) cracking in a thermal cracker at least a portion of the waxy fraction to produce the thermally-cracked effluent;

(E) optionally, hydrotreating at least a portion of or at least a fraction of the thermally-cracked effluent;

(F) hydrotreating the light diesel distillate to produce a hydrotreated light diesel distillate;

(G) optionally, hydroprocessing the heavy diesel distillate; and

(H) isomerizing the heavy diesel distillate to produce an isomerized effluent.

24. The process of claim 23, wherein the hydrocarbon synthesis reactor comprises a Fischer-Tropsch reactor.

25. The process of claim 23, wherein step (C) further produces a naphtha distillate comprising more than 80% linear hydrocarbons.

26. The process of claim 23 further comprising hydrotreating at least a portion of the thermally-cracked effluent of step (D).

27. The process of claim 23, wherein the light diesel distillate comprises primarily C₁₀-C₁₆ hydrocarbons, and the heavy diesel distillate comprises primarily C₁₇-C₂₃ hydrocarbons.

28. The process of claim 23, wherein the cracking occurs between about 380°

C. and about 700°

C.

29. The process of claim 23, wherein the cracking occurs between about 380°

C. and about 550°

C.

30. The process of claim 23, wherein hydroprocessing in step (G) comprises hydrotreating the heavy diesel distillate.

31. The process of claim 30, wherein hydrotreating comprises temperatures between about 170°

C. and about 400°

C.

32. The process of claim 30, wherein hydrotreating comprises temperatures between about 80°

C. and about 250°

C.

33. The process of claim 23, wherein isomerizing the heavy diesel distillate occurs at temperatures between about 180°

C. and about 380°

C.

34. The process of claim 23, wherein the diesel is formed by combining at least a portion of the hydrotreated light diesel distillate;

at least a portion or a fraction of the thermally-cracked effluent; and

at least a portion or fraction of the isomerized effluent.

35. The process of claim 23, wherein the diesel comprises a light fraction comprising between about 25 and about 40 percent by volume of the most volatile hydrocarbons in the diesel, said light fraction comprising less than 10% of branched hydrocarbons.

36. The process of claim 35, wherein the light fraction has at least about 90 percent linear hydrocarbons.

37. The process of claim 35, wherein the diesel comprises a heavy fraction comprising between about 10 and about 40 percent by volume of the least volatile hydrocarbons in the diesel, said heavy fraction having at least about 30 percent branched hydrocarbons.

38. The process of claim 23, wherein the diesel comprises a light fraction characterized by a 5% boiling poinit less than about 360°

F. and a 95% boiling point between about 425°

F. and 47520 F., and wherein said light fraction has at least about 80 percent linear hydrocarbons.

39. The process of claim 23, wherein the diesel comprises C₁₇-C₂₃ hydrocarbons having at least about 30 percent branched hydrocarbons.

40. The process of claim 39, wherein the diesel further comprises C₁₇-C₂₃ hydrocarbons having at least about 40 percent branched hydrocarbons.

41. The process of claim 23, wherein the diesel comprises a heavy fraction characterized by a 5% boiling point between about 500°

F. and 550°

F. and a 95% boiling point greater than about 630°

F., and wherein said heavy fraction has at least about 30 percent branched hydrocarbons.

42. A synthetic middle distillate suitable for use as a liquid fuel or fuel blend comprising primarily about C₁₀-C₂₂ hydrocarbons, said synthetic middle distillate comprising at least two fractions,

a light fraction characterized by a 5% boiling point less than about 360°

F. and a 95% boiling point between about 500°

F. and 550°

F., wherein said light fraction has at least about 90 percent linear hydrocarbons; and

a heavy fraction characterized by a 5% boiling point between about 500°

F. and 550°

F. and a 95% boiling point greater than about 630°

F., wherein said heavy fraction has at least about 30 percent branched hydrocarbons.

43. The synthetic middle distillate of claim 42, wherein the heavy fraction has at least about 40 percent branched hydrocarbons.

44. The synthetic middle distillate of claim 42, wherein the heavy fraction further comprises linear hydrocarbons.

45. The synthetic middle distillate of claim 44, wherein the branched hydrocarbons in the heavy fraction of the diesel material are provided by at least a fraction of an isomerized Fischer-Tropsch heavy diesel product stream.

46. The synthetic middle distillate of claim 42, wherein said light fraction has at least about 95 percent linear hydrocarbons.

47. The synthetic middle distillate of claim 42, wherein said light fraction comprises not more than about 10 percent branched hydrocarbons.

48. The synthetic middle distillate of claim 42, wherein the linear hydrocarbons in the synthetic middle distillate are provided by at least a fraction of a hydrotreated Fischer-Tropsch synthesis product stream.

49. The synthetic middle distillate of claim 48, wherein the linear hydrocarbons in the synthetic distillate are further provided by at least a fraction of a hydrotreated thermally-cracked Fischer-Tropsch synthesis waxy product stream.

50. The synthetic middle distillate of claim 42, wherein the synthetic middle distillate comprises an amount of the heavy fraction sufficient to improve at least one cold-flow property of the synthetic middle distillate selected from the group consisting of pour point, cloud point and cold filter plugging point.

51. A synthetic middle distillate suitable for use as a fuel or fuel blend comprising at least two fractions,

a light hydrocarbon fraction comprising between about 25 and about 40 percent by volume of the most volatile hydrocarbons in the synthetic middle distillate, wherein said light fraction comprises less than 10 percent of branched hydrocarbons;

and

a heavy hydrocarbon fraction comprising between about 10 and about 40 percent by volume of the least volatile hydrocarbons in the synthetic middle distillate, wherein said heavy fraction includes at least about 30 percent branched hydrocarbons.

52. The synthetic middle distillate of claim 51, wherein the heavy fraction has at least about 40 percent branched hydrocarbons.

53. The synthetic middle distillate of claim 51, wherein the light fraction is characterized by a 5% boiling point less than about 360°

F. and a 95% boiling point between about 425°

F. and 475°

F.

54. The synthetic middle distillate of claim 51, wherein the heavy fraction is characterized by a 5% boiling point between about 525°

F. and 575°

F. and a 95% boiling point greater than about 630°

F.

55. The synthetic middle distillate of claim 51, wherein the synthetic middle distillate is a diesel fuel.

56. The synthetic middle distillate of claim 55, wherein the synthetic middle distillate is a diesel fuel characterized by a 5% boiling point between about 340°

F .and about 360°

F. and a 95% boiling point between about 620°

F. and about 640°

F.

57. The synthetic middle distillate of claim 51, wherein the synthetic middle distillate is a jet fuel.

58. The synthetic middle distillate of claim 57, wherein the synthetic middle distillate is a jet fuel characterized by an initial boiling point of about 250°

F. and a final boiling point between about 475°

F. and about 550°

F.