Process for producing olefins

• US 20050283038A1
• Filed: 06/18/2004
• Published: 12/22/2005
• Est. Priority Date: 06/18/2004
• Status: Active Grant

• Current Assignee: ExxonMobil Chemical Patents Inc. (Exxon Mobil Corporation)
• Original Assignee: ExxonMobil Chemical Patents Inc. (Exxon Mobil Corporation)
• Inventors: Brinen, Jeffrey L., Kuechler, Keith H., Ruziska, Philip A.
• Granted Patent: US 7,332,639 B2
• Time in Patent Office: Days
• US Class Current: 585/639
• CPC Class Codes: C07C 1/20 starting from organic compounds containing only oxygen atoms as heteroatoms
• CPC Class Codes: C07C 11/02 Alkenes
• CPC Class Codes: C07C 7/11 by absorption, i.e. purification or separation of gaseous hydrocarbons with the aid of liquids
• CPC Class Codes: Y02P 30/20 using bio-feedstock
• CPC Class Codes: Y02P 30/40 Ethylene production

Abstract

A process is described for producing an olefins stream from a first vapor effluent stream from an oxygenate to olefin conversion reaction, said first vapor effluent stream comprising C₂ and C₃ olefins, C₄ hydrocarbons, and C₂ to C₆ carbonyl compounds. In the process, the temperature and pressure of the first vapor effluent stream are adjusted to produce a second vapor effluent stream having a pressure ranging from about 100 psig to about 350 psig (790 to 2514 kPa) and a temperature ranging from about 70° F. to about 120° F. (21 to 49° C.), said second vapor effluent stream containing about 50 wt. % or more C₄ hydrocarbons based upon the total weight of C₄ hydrocarbons in the first vapor effluent stream. The second vapor effluent stream is then washed with a liquid alcohol-containing stream to produce a third vapor effluent stream, whereafter the third vapor effluent stream is washed with liquid water to provide a fourth vapor effluent stream comprising the C₂ and C₃ olefins and about 1.0 wt. % or less C₂ to C₆ carbonyl compounds.

Claims

1. A process for producing an olefins stream comprising:

(a) providing a first vapor effluent stream from an oxygenate to olefin conversion reaction, said first vapor effluent stream comprising C₂ and C₃ olefins, C₄ hydrocarbons, and C₂ to C₆ carbonyl compounds;

(b) adjusting the temperature and pressure of the first vapor effluent stream to produce a second vapor effluent stream having a pressure ranging from about 100 psig to about 350 psig (790 to 2514 kPa) and a temperature ranging from about 70°

F. to about 120°

F. (21 to 49°

C.), said second vapor effluent stream containing about 50 wt. % or more of the C₄ hydrocarbons in the first vapor effluent stream;

(c) washing the second vapor effluent stream with a liquid alcohol-containing stream to produce a third vapor effluent stream; and

(d) washing the third vapor effluent stream with liquid water to provide a fourth vapor effluent stream, said fourth vapor effluent stream comprising about 1.0 wt. % or less C₂ to C₆ carbonyl compounds.

2. The process of claim 1 wherein said adjusting (b) produces said second vapor effluent stream with a pressure ranging from about 120 psig to about 290 psig (928 to 2101 kPa).

3. The process of claim 1 wherein said adjusting (b) produces said second vapor effluent stream with a pressure ranging from about 140 psig to about 170 psig (1023 to 1273 kPa).

4. The process of claim 1 wherein said adjusting (b) produces said second vapor effluent stream with a temperature ranging from about 80°

F. to about 110°

F. (27 to 43°

C.).

5. The process of claim 1 wherein said adjusting (b) produces said second vapor effluent stream with a temperature ranging from about 90°

F. to about 100°

F. (32 to 38°

C.).

6. The process of claim 1 wherein said second vapor effluent stream contains at least 60 wt. % of the C₄ hydrocarbons in the first vapor effluent stream.

7. The process of claim 1 wherein said second vapor effluent stream contains at least 70 wt % of the C₄ hydrocarbons in the first vapor effluent stream.

8. The process of claim 1 wherein said second vapor effluent stream contains at least 80 wt % of the C₄ hydrocarbons in the first vapor effluent stream.

9. The process of claim 1 wherein said second vapor effluent stream contains at least 90 wt % of the C₄ hydrocarbons in the first vapor effluent stream.

10. The process of claim 1 wherein said second vapor effluent stream contains at least 95 wt % of the C₄ hydrocarbons provided in the first vapor effluent stream.

11. The process of claim 1 wherein the washing (c) is conducted at a temperature of at least 80°

F. (27°

C.).

12. The process of claim 1 wherein the washing (c) is conducted at a temperature of at least 90°

F. (32°

C.).

13. The process of claim 1 wherein the washing (c) is conducted at a temperature of no more than 120°

F. (49°

C.).

14. The process of claim 1 wherein the washing (c) is conducted at a temperature of no more than 110°

F. (43°

C.).

15. The process of claim 1 wherein the washing (c) is conducted at a temperature of no more than 100°

F. (38°

C.).

16. The process of claim 1 wherein the washing (c) is conducted at a pressure of from about 100 psig to about 350 psig (790 to 2514 kPa).

17. The process of claim 1 wherein the washing (c) is conducted at a pressure of from about 120 psig to about 290 psig (928 to 2101 kPa).

18. The process of claim 1 wherein the washing (c) is conducted at a pressure of from about 140 psig to about 170 psig (1023 to 1273 kPa).

19. The process of claim 1 wherein the liquid alcohol-containing stream comprises methanol, or ethanol, or methanol and water, or ethanol and water, or methanol and ethanol and water.

20. The process of claim 1 wherein the liquid alcohol-containing stream comprises methanol.

21. The process of claim 20 wherein the methanol has a purity of at least 40 wt %.

22. The process of claim 20 wherein the methanol has a purity of at least 75 wt %.

23. The process of claim 20 wherein the methanol has a purity of at least 95 wt %.

24. The process of claim 20 wherein the methanol has a purity of at least 99 wt %.

25. The process of claim 20 wherein the amount of methanol employed in the washing (c) is at least 0.03 lb methanol (as pure methanol) per lb of the second vapor effluent stream.

26. The process of claim 20 wherein the amount of methanol employed in the washing (c) is at least 0.05 lb methanol (as pure methanol) per lb of the second vapor effluent stream.

27. The process of claim 20 wherein the amount of methanol employed in the washing (c) is at least 0.07 lb methanol (as pure methanol) per lb of the second vapor effluent stream.

28. The process of claim 20 wherein the amount of methanol employed in the washing (c) is no more than 0.5 lb methanol (as pure methanol) per lb of the second vapor effluent stream.

29. The process of claim 20 wherein the amount of methanol employed in the washing (c) is no more than 0.2 lb methanol (as pure methanol) per lb of the second vapor effluent stream.

30. The process of claim 20 wherein the amount of methanol employed in the washing (c) is no more than 0.1 lb methanol (as pure methanol) per lb of the second vapor effluent stream.

31. The process of claim 1 wherein the washing (d) is conducted at a temperature of at least 80°

F. (27°

C.).

32. The process of claim 1 wherein the washing (d) is conducted at a temperature of at least 90°

F.

33. The process of claim 1 wherein the washing (d) is conducted at a temperature of no more than 120°

F. (49°

C.).

34. The process of claim 1 wherein the washing (d) is conducted at a temperature of no more than 110°

F. (43°

C.).

35. The process of claim 1 wherein the washing (d) is conducted at a temperature of no more than 100°

F. (38°

C.).

36. The process of claim 1 wherein the washing (d) is conducted at a pressure of from about 100 psig to about 350 psig (790 to 2514 kPa).

37. The process of claim 1 wherein the washing (d) is conducted at a pressure of from about 120 psig to about 290 psig (928 to 2101 kPa).

38. The process of claim 1 wherein the washing (d) is conducted at a pressure of from about 140 psig to about 170 psig (1023 to 1273 kPa).

39. The process of claim 1 wherein said fourth vapor effluent stream comprises about 0.5 wt. % or less C₂ to C₆ carbonyl compounds.

40. The process of claim 1 wherein said fourth vapor effluent stream comprises about 0.1 wt. % or less C₂ to C₆ carbonyl compounds.

41. The process of claim 1 wherein said fourth vapor effluent stream comprises about 500 ppmwt or less C₂ to C₆ carbonyl compounds.

42. The process of claim 1 wherein said fourth vapor effluent stream comprises 1.0 wt. % or less of methanol.

43. The process of claim 1 wherein said fourth vapor effluent stream comprises 0.1 wt % or less of methanol.

44. The process of claim 1 wherein said fourth vapor effluent stream comprises 500 ppm wt or less of methanol.

45. The process of claim 1 and further comprising removing acid gas from the fourth vapor effluent stream.

46. The process of claim 45 and further comprising drying the fourth vapor effluent stream such that the dried fourth vapor effluent stream has a dew point of no greater than −

150°

F. (−

101°

C.).

47. The process of claim 46 wherein said drying of the fourth vapor effluent stream is conducted after said removing of acid gas therefrom.

48. The process of claim 1 and also comprising fractionating the C₃ and C₄ hydrocarbons contained in the fourth vapor effluent stream to produce a C₃ containing stream and a first C₄ containing stream.

49. The process of claim 48 wherein the first C₄ containing stream comprises less than 5 wt % C₃ and lower hydrocarbons.

50. The process of claim 48 wherein the first C₄ containing stream comprises less than 1 wt % C₃ and lower hydrocarbons.

51. The process of claim 48 wherein the first C₄ containing stream comprises less than 0.1 wt % C₃ and lower hydrocarbons.

52. The process of claim 48 wherein said first C₄ containing stream comprises less than 5 wt % C₂ to C₆ carbonyl compounds.

53. The process of claim 48 wherein said first C₄ containing stream comprises less than 1 wt % C₂ to C₆ carbonyl compounds.

54. The process of claim 48 wherein said first C₄ containing stream comprises less than 5000 ppm wt C₂ to C₆ carbonyl compounds.

55. The process of claim 48 wherein said first vapor effluent stream in (a) and said first C₄ containing stream further comprise C₅+ hydrocarbons and said first C₄ containing stream is subjected to further fractionation to separate C₅+ hydrocarbons therefrom and create a C₄ hydrocarbon product stream.

56. The process of claim 48 wherein said first vapor effluent stream in (a) further comprises dimethyl ether (DME) and wherein said fractionating the C₃ and C₄ hydrocarbons contained in the fourth vapor effluent stream produces a C₃ containing stream and a first C₄ and DME containing stream, and said first C₄ and DME containing stream is subjected to further fractionation to remove dimethyl ether therefrom and produce said first C₄ containing stream.

57. The process of claim 48 wherein said adjusting (b) separates a second liquid C₄ containing stream from said first vapor effluent stream and said second liquid C₄ containing stream is combined with said first C₄ containing stream to produce a third C₄ containing stream comprising less than 5 wt % C₂ to C₆ carbonyl compounds.

58. The process of claim 57 wherein said third C₄ containing stream comprises less than 1 wt % of C₂ to C₆ carbonyl compounds.

59. The process of claim 57 wherein said third C₄ containing strearni comprises less than 5000 ppm wt C₂ to C₆ carbonyl compounds.

60. A process for producing olefins comprising:

(a) contacting an oxygenate feed with a molecular sieve catalyst to produce a vapor product stream comprising C₂ and C₃ olefins, C₄ hydrocarbons, water and oxygenate compounds, including C₂ to C₆ carbonyl compounds;

(b) cooling said product stream to condense therefrom a liquid stream rich in water and oxygenate compounds and produce a first vapor effluent stream comprising C₂ and C₃ olefins, C₄ hydrocarbons, and C₂ to C₆ carbonyl compounds;

(c) compressing said first vapor effluent stream to produce a second vapor effluent stream having a pressure ranging from about 100 psig to about 350 psig (790 to 2514 kPa) and a temperature ranging from about 70°

F. to about 120°

F. (21 to 49°

C.), said second vapor effluent stream containing about 50 wt. % or more of the C₄ hydrocarbons in the first vapor effluent stream;

(d) washing the second vapor effluent stream with a liquid methanol-containing stream to produce a third vapor effluent stream and a liquid oxygenate-containing methanol stream; and

(e) washing the third vapor effluent stream with liquid water to produce a fourth vapor effluent stream and an oxygenate-containing water stream, said fourth vapor effluent stream comprising about 1.0 wt. % or less C₂ to C₆ carbonyl compounds.

61. The process of claim 60 wherein said oxygenate feed comprises methanol and/or ethanol.

62. The process of claim 60 wherein said oxygenate feed comprises methanol.

63. The process of claim 60 wherein said second vapor effluent stream has a pressure ranging from about 120 psig to about 290 psig (928 to 2101 kPa).

64. The process of claim 60 wherein said second vapor effluent stream has a pressure ranging from about 140 psig to about 170 psig (1023 to 1273 kPa).

65. The process of claim 60 wherein said second vapor effluent stream has a temperature ranging from about 80°

F. to about 110°

F. (27 to 43°

C.).

66. The process of claim 60 wherein second vapor effluent stream has a temperature ranging from about 90°

F. to about 100°

F. (32 to 38°

C.).

67. The process of claim 60 wherein the washing (d) is conducted at a temperature of about 80°

F. (27°

C.) to about 120°

F. (49°

C.).

68. The process of claim 60 wherein the washing (d) is conducted at a temperature of about 90°

F. (32°

C.) to about 110°

F. (43°

C.).

69. The process of claim 60 wherein the washing (d) is conducted at a pressure of from about 100 psig to about 350 psig (790 to 2514 kPa).

70. The process of claim 60 wherein the washing (d) is conducted at a pressure of from about 120 psig to about 290 psig (928 to 2101 kPa).

71. The process of claim 60 wherein the washing (d) is conducted at a pressure of from about 140 psig to about 170 psig (1023 to 1273 kPa).

72. The process of claim 60 wherein the amount of liquid methanol containing stream employed in the washing (d) is about 0.03 lb to about 0.5 lb methanol (as pure methanol) per lb of the second vapor effluent stream.

73. The process of claim 60 wherein the amount of liquid methanol containing stream employed in the washing (d) is about 0.05 lb to about 0.2 lb methanol (as pure methanol) per lb of the second vapor effluent stream.

74. The process of claim 60 wherein the amount of liquid methanol containing stream employed in the washing (d) is about 0.07 lb to about 0.1 lb methanol (as pure methanol) per lb of the second vapor effluent stream.

75. The process of claim 60 wherein the washing (e) is conducted at a temperature of about 80°

F. (27°

C.) to about 120°

F. (49°

C.).

76. The process of claim 60 wherein the washing (e) is conducted at a temperature of about 90°

F. to about 110°

F. (43°

C.).

77. The process of claim 60 wherein the washing (e) is conducted at a pressure of from about 100 psig to about 350 psig (790 to 2514 kPa).

78. The process of claim 60 wherein the washing (e) is conducted at a pressure of from about 120 psig to about 290 psig (928 to 2101 kPa).

79. The process of claim 60 wherein the washing (e) is conducted at a pressure of from about 140 psig to about 170 psig (1023 to 1273 kPa).

80. The process of claim 60 wherein at least part of said oxygenate-containing water stream and at least part of said oxygenate-containing methanol stream are fractionated to produce an oxygenate-rich overhead stream and a water-rich liquid bottoms stream.

81. The process of claim 80 wherein at least a part of said oxygenate-rich overhead stream is recycled for said contacting (a).

82. The process of claim 80 wherein at least a part of said water-rich liquid bottoms stream is recycled for use as said liquid water in said washing (e).

83. The process of claim 60 wherein at least a part of said liquid stream rich in water from (b) is fractionated to produce an oxygenate-rich overhead stream and a water-rich liquid bottoms stream.

84. The process of claim 80 wherein at least a part of said oxygenate-rich overhead stream is recycled for said contacting (a).

85. The process of claim 80 wherein at least a part of said water-rich liquid bottoms stream is recycled for use as said liquid water in said washing (e).