Process for removal of alkynes and/or dienes from an olefin stream

• US 20040192982A1
• Filed: 03/28/2003
• Published: 09/30/2004
• Est. Priority Date: 03/28/2003
• Status: Active Grant

• Current Assignee: ExxonMobil Chemical Patents Inc. (Exxon Mobil Corporation)
• Original Assignee: ExxonMobil Chemical Patents Inc. (Exxon Mobil Corporation)
• Inventors: Kuechler, Keith Holroyd, Lumgair, David R. Jr.
• Granted Patent: US 7,115,789 B2
• Time in Patent Office: Days
• US Class Current: 585/259
• 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 7/163 by hydrogenation
• CPC Class Codes: C07C 7/167 for removal of compounds containing a triple carbon-to-carbon bond
• CPC Class Codes: C10G 45/32 Selective hydrogenation of the diolefin or acetylene compounds
• CPC Class Codes: C10G 45/40 containing platinum group metals or compounds thereof
• CPC Class Codes: C10G 65/06 at least one step being a selective hydrogenation of the diolefins
• CPC Class Codes: Y02P 30/20 using bio-feedstock
• CPC Class Codes: Y02P 30/40 Ethylene production

Abstract

The present invention is a process for removing alkynes and/or dienes from an olefin product stream withdrawn from an oxygenate-to-olefins reactor. The process comprises hydrogenating a first olefin stream that has alkynes and/or dienes in the presence of excess hydrogen and a first hydrogenation catalyst. The hydrogenation of the first olefin stream produces a second olefin stream that has unreacted hydrogen. The second olefin stream is contacted with a second hydrogenation catalyst producing a third olefin stream. The third olefin stream has low levels of hydrogen and alkynes and/or dienes.

Claims

1. A process for removing byproducts selected from the group consisting of alkynes, dienes and mixtures thereof from an olefin product stream withdrawn from an oxygenate-to-olefins reactor, the process comprising the steps of:

(a) hydrogenating a first olefin stream comprising olefins and byproducts in the presence of excess hydrogen and a first hydrogenation catalyst producing a second olefin stream that has unreacted hydrogen; and

(b) contacting the second olefin stream with a second hydrogenation catalyst producing a third olefin stream having about 10 mppm or less hydrogen and about 1 mppm or less byproducts based upon the composition of the third olefin stream.

2. The process of claim 1, wherein at least a portion of the excess hydrogen is from a hydrogen source stream, the hydrogen source stream having about 90 mol. % or more hydrogen based upon the composition of the hydrogen source stream.

3. The process of claim 2, wherein the hydrogen source stream has about 95 mol. % or more hydrogen based upon the composition of the hydrogen source stream.

4. The process of claim 2, wherein the hydrogen source stream has about 98 mol. % or more hydrogen based upon the composition of the hydrogen source stream.

5. The process of claim 2, wherein a combined stream of the first olefin stream and the hydrogen source stream has about 500 mppm or less methane based upon the composition of the combined stream.

6. The process of claim 2, wherein a combined stream of the first olefin stream and the hydrogen source stream has about 1 mppm or less CO based upon the composition of the combined stream.

7. The process of claim 1, wherein a combined stream of the first olefin stream and the hydrogen source stream has about 1 mppm or less CO₂ based upon the composition of the combined stream.

8. The process of claim 2, wherein the first olefin stream has about 1 mppm or less CO₂ based upon the composition of the combined stream.

9. The process of claim 1, wherein about 1.05 moles or more of hydrogen are present for every mole of byproducts in the first olefin stream.

10. The process of claim 1, wherein from about 1.5 moles to about 50 moles of hydrogen are present for every mole of byproducts in the first olefin stream.

11. The process of claim 1, wherein from about 1.5 moles to about 10 moles of hydrogen are present for every mole of byproducts in the first olefin stream.

12. The process of claim 2, wherein the hydrogen source stream is from a source selected from the group comprising pipeline hydrogen, hydrogen from reformed naphtha, hydrogen from refinery streams, hydrogen from bottled sources, hydrogen from water electrolysis reactors, hydrogen from refinery streams and hydrogen from decomposition of oxygenates.

13. The process of claim 1, further comprising the step of (c) heating the first olefin stream.

14. The process of claim 1, wherein the first olefin stream is heated to a temperature ranging from about 100°

F. (38°

C.) to about 250°

F. (121°

C.).

15. The process of claim 1, wherein the first olefin stream is heated to a temperature ranging from about 120°

F. (49°

C.) to about 200°

F. (93°

C.).

16. The process of claim 1, wherein the first olefin stream is heated to a temperature ranging from about 150°

F. (66°

C.) to about 190°

F. (88°

C.).

17. The process of claim 1, wherein the step of (a) hydrogenating occurs at a pressure ranging from about 50 psia (344 kPaa) to about 400 psia (2760 kPaa).

18. The process of claim 1, wherein the step of (a) hydrogenating occurs at a pressure ranging from about 200 psia (1380 kPaa) to about 300 psia (2070 kPaa).

19. The process of claim 1, wherein the step of (a) hydrogenating occurs at a pressure ranging from about 250 psia (1720 kPaa) to about 300 psia (2070 kPaa).

20. The process of claim 1, wherein the first catalyst is an elemental Group VIII metal catalysts.

21. The process of claim 1, wherein the first catalyst is an elemental noble metal on a substrate selected from the group consisting of silica, alumina and mixtures thereof with a co-catalyst selected from the group consisting of elemental silver, vanadium, iodine and combinations thereof.

22. The process of claim 1, wherein the first catalyst is an elemental palladium catalyst.

23. The process of claim 1, wherein the first catalyst is an elemental palladium catalyst on a substrate selected from the group consisting of silica, alumina and/or mixtures thereof with a co-catalyst selected from the group consisting of elemental silver, vanadium, iodine and combinations thereof.

24. The process of claim 1, wherein the first olefin stream is heated with the third olefin stream in a heat exchanger.

25. The process of claim 1, wherein the first olefin stream contains 50 mol.% or more olefin based upon the composition of the first olefin stream.

26. The process of claim 1, wherein the first olefin stream contains about 90 mol. % or more olefin based upon the composition of the first olefin stream.

27. The process of claim 1, wherein the first olefin stream contains about 98 mol. % or more olefin based upon the composition of the first olefin stream.

28. The process of claim 1, wherein the first olefin stream contains about 25 mol. % or more ethylene based upon the composition of the first olefin stream.

29. The process of claim 1, wherein the first olefin stream comprises about 200 mppm or less alkynes and or dienes.

30. The process of claim 1, wherein the byproducts include acetylene and the first olefin stream comprises about 500 mppm or less byproducts based upon the composition of the first olefin stream.

31. The process of claim 1, wherein the byproducts include acetylene and the first olefin stream comprises about 200 mppm or less byproducts based upon the composition of the first olefin stream.

32. The process of claim 1, wherein the first olefin stream comprises about 25 mol. % or more propylene based upon the composition of the first olefin stream.

33. The process of claim 1, wherein the first olefin stream comprises about 90 mol. % or more propylene based upon the composition of the first olefin stream.

34. The process of claim 1, wherein the alkyne is methyl acetylene and the diene is propadiene and the first olefin stream comprises about 500 mppm or less byproducts based upon the composition of the first olefin stream.

35. The process of claim 1, wherein the temperature of the second olefin stream ranges from about 100°

F. (38°

C.) to about 250°

F. (121°

C.).

36. The process of claim 1, wherein the temperature of the second olefin stream ranges from about 120°

F. (49°

C.) to about 200°

F. (93°

C.).

37. The process of claim 1, wherein the temperature of the second olefin stream ranges from about 150°

F. (66°

C.) to about 190°

F. (88°

C.).

38. The process of claim 1, wherein the step of (b) contacting occurs at a pressure ranging from about 50 psia (344 kPaa) to about 400 psia (2760 kPaa).

39. The process of claim 1, wherein the step of (b) contacting occurs at a pressure ranging from about 200 psia (1380 kPaa) to about 300 psia (2070 kPaa).

40. The process of claim 1, wherein the step of (b) contacting occurs at a pressure ranging from about 250 psia (1720 kPaa) to about 300 psia (2070 kPaa).

41. The process of claim 1, wherein the second catalyst is an elemental Group VIII metal catalysts.

42. The process of claim 1, wherein the second catalyst is an elemental noble metal on a substrate selected from the group consisting of silica and/or alumina with a co-catalyst selected from the group comprising elemental iron catalyst, elemental nickel catalyst, and mixtures thereof.

43. The process of claim 1, wherein the second catalyst is an elemental palladium catalyst.

44. The process of claim 1, wherein the second catalyst is an elemental palladium catalyst on a substrate selected from the group consisting of silica, alumina and mixtures thereof with a co-catalyst selected from the group consisting of elemental iron, elemental nickel and mixtures thereof.

45. The process of claim 1, wherein the first catalyst is the same as the second catalyst.

46. The process of claim 1, wherein the step of (a) hydrogenating occurs in a first bed of a reactor vessel and the step of (b) contacting occurs in a second bed of a reactor vessel.

47. A process for making a polyolefin product from an oxygenate feed stream, the process comprising the steps of:

(a) contacting the oxygenate feed stream with a molecular sieve catalyst in an oxygenate-to-olefin reactor thereby producing a first olefin stream having olefins selected from the group comprising ethylene, propylene and mixtures thereof and byproducts selected from the group consisting of alkynes, dienes and mixtures thereof, wherein there is about 200 mppm or less of byproducts for every mole of olefins in the first product stream;

(b) adding hydrogen to the first olefin stream, wherein the mole ratio of hydrogen to byproducts in the first product stream is about 1.05;

1 or higher;

(c) hydrogenating the first olefin stream in the presence of a first hydrogenation catalyst producing a second olefin stream comprising prime olefins and unreacted hydrogen;

(d) contacting the second olefin stream with a second hydrogenation catalyst producing a third olefin stream, wherein the third olefin stream has about 10 mppm or less hydrogen based upon the composition of the third olefin stream; and

(e) converting the prime olefins from the third olefin stream to the polyolefin product.

48. The process of claim 47, wherein at least a portion of the hydrogen is from a hydrogen source stream having about 98 mol. % or more hydrogen based upon the composition of the hydrogen source stream.

49. The process of claim 48, wherein a combined stream of the first olefin stream and the hydrogen source stream has about 500 mppm or less methane based upon the composition of the combined stream.

50. The process of claim 48, wherein a combined stream of the first olefin stream and the hydrogen source stream has about 1 mppm or less CO based upon the composition of the combined stream.

51. The process of claim 48, wherein a combined stream of the first olefin stream and the hydrogen source stream has about 1 mppm or less CO₂ based upon the composition of the combined stream.

52. The process of claim 47, wherein from about 1.5 moles to about 10 moles of hydrogen are present for every mole of byproducts in the first olefin stream.

53. The process of claim 48, wherein the hydrogen source stream is from a source selected from the group comprising pipeline hydrogen, hydrogen from reformed naphtha, hydrogen from refinery streams, hydrogen from bottled sources, hydrogen from water electrolysis reactors, hydrogen from refinery streams and hydrogen from decomposition of oxygenates.

54. The process of claim 47, wherein the first olefin stream is heated to a temperature ranging from about 100°

F. (38°

C.) to about 250°

F. (121°

C.)

55. The process of claim 47, wherein the step of (a) hydrogenating occurs at a pressure ranging from about 50 psia (344 kPaa) to about 400 psia (2760 kPaa).

56. The process of claim 47, wherein the first catalyst and second catalyst are an elemental Group VIII metal catalysts.

57. The process of claim 47, wherein the first catalyst and second catalyst are elemental palladium catalyst.

58. The process of claim 47, wherein the first olefin stream contains about 98 mol. % or more olefin based upon the composition of the first olefin stream.

59. The process of claim 47, wherein the first olefin stream comprises about 90 mol. % or more ethylene based upon the composition of the first olefin stream.

60. The process of claim 47, wherein the byproducts include acetylene and the first olefin stream comprises about 50 mppm or less byproducts based upon the composition of the first olefin stream.

61. The process of claim 47, wherein the first olefin stream comprises about 90 mol. % or more propylene based upon the composition of the first olefin stream.

62. The process of claim 47, wherein the byproducts are selected from the group comprising methyl acetylene, propadiene and mixtures thereof and the first olefin stream comprises about 50 mppm or less byproducts based upon the composition of the first olefin stream.

63. The process of claim 47, wherein the temperature of the second olefin stream ranges from about 100°

F. (38°

C.) to about 250°

F. (121°

C.)

64. The process of claim 47, wherein the step of (b) contacting occurs at a pressure ranging from about 50 psia (344 kPaa) to about 400 psia (2760 kPaa).

89. The process of claim 47, wherein the first catalyst and second catalyst are elemental Group VIII metal catalysts.

65. A process for producing an ethylene stream from an oxygenate feed stream, the process comprising the steps of:

(a) contacting the oxygenate feed stream with a molecular sieve catalyst in a reactor producing a first olefin stream having ethylene, higher boiling point compounds and acetylene;

(b) separating a majority of the ethylene and a majority of the acetylene from a majority of the higher boiling point compounds producing a first ethylene stream comprising the majority of the ethylene and the majority of the acetylene;

(c) hydrogenating the acetylene in the first ethylene stream in the presence of excess hydrogen producing a second ethylene stream, wherein the second ethylene stream comprises unreacted hydrogen;

(d) reacting the unreacted hydrogen in the second ethylene stream producing a third ethylene stream; and

wherein the third ethylene stream has less than 10 mppm hydrogen based upon the composition of the third ethylene stream and wherein about 1 mol. % or less of the ethylene in the first olefin stream is converted in the step of (c) hydrogenating and the step of (d) reacting, based upon the composition of ethylene in the first olefin stream.

66. The process of claim 65, wherein at least a portion of at least a portion of the excess hydrogen is from a hydrogen source stream having about 98 mol. % or more hydrogen based upon the composition of the hydrogen source stream.

67. The process of claim 66, wherein a combined stream of the first ethylene stream and the hydrogen source stream has about 500 mppm or less methane based upon the composition of the combined stream.

68. The process of claim 66, wherein a combined stream of the first ethylene stream and the hydrogen source stream has about 1 mppm or less CO based upon the composition of the combined stream.

69. The process of claim 66, wherein a combined stream of the first ethylene stream and the hydrogen source stream has about 1 mppm or less CO₂ based upon the composition of the combined stream.

70. The process of claim 65, wherein from about 1.5 moles to about 10 moles of hydrogen are present for every mole of acetylene in the first ethylene stream.

71. The process of claim 66, wherein the hydrogen source stream is from a source selected from the group comprising pipeline hydrogen, hydrogen from reformed naphtha, hydrogen from refinery streams, hydrogen from bottled sources, hydrogen from water electrolysis reactors, hydrogen from refinery streams and hydrogen from decomposition of oxygenates.

72. The process of claim 65, wherein the first ethylene stream is heated to a temperature ranging from about 100°

F. (38°

C.) to about 250°

F. (121°

C.).

73. The process of claim 65, wherein the step of (a) hydrogenating occurs at a pressure ranging from about 50 psia (344 kPaa) to about 400 psia (2760 kPaa).

74. The process of claim 65, wherein the first catalyst and second catalyst are elemental Group VIII metal catalysts.

75. The process of claim 65, wherein the first catalyst and second catalyst are elemental palladium catalyst.

76. The process of claim 65, wherein the first ethylene comprises about 90 mol. % or more ethylene based upon the composition of the first olefin stream.

77. The process of claim 65, wherein the first ethylene stream comprises about 500 mppm or less acetylene based upon the composition of the first ethylene stream.

78. The process of claim 65, wherein the temperature of the second ethylene stream ranges from about 100°

F. (38°

C.) to about 250°

F. (121°

C.).

79. The process of claim 65, wherein the step of (b) contacting occurs at a pressure ranging from about 250 psia (1720 kPaa) to about 300 psia (2070 kPaa).

80. A process for producing a propylene stream from an oxygenate feed stream, the process comprising the steps of:

(a) contacting the oxygenate feed stream with a molecular sieve catalyst in a reactor producing a first olefin stream having propylene, higher boiling point compounds or lower boiling point compounds and byproducts selected from the group comprising methyl acetylene, propadiene and mixtures thereof;

(b) separating a majority of the propylene and a majority of the byproducts from a majority of the higher boiling point compounds and/or lower boiling point compounds producing a first propylene stream comprising the majority of the propylene and the majority of the byproducts comprising methyl acetylene, propadiene and mixtures thereof;

(c) hydrogenating the byproducts in the first propylene stream in the presence of excess hydrogen producing a second propylene stream, wherein the second propylene stream comprises unreacted hydrogen;

(d) reacting the unreacted hydrogen in the second propylene stream producing a third propylene stream; and

wherein the third propylene stream has about 10 mppm or less hydrogen based upon the composition of the third propylene stream and wherein about 1 mol. % or less of the propylene in the first olefin stream is converted in the step of (c) hydrogenating and the step of (d) reacting, based upon the composition of the propylene in the first olefin stream.

81. The process of claim 80, wherein at least a portion of the hydrogen is from a hydrogen source stream having about 98 mol. % or more hydrogen based upon the composition of the hydrogen source stream.

82. The process of claim 81, wherein a combined stream of the first propylene stream and the hydrogen source stream has about 500 mppm or less methane based upon the composition of the combined stream.

83. The process of claim 81, wherein a combined stream of the first propylene stream and the hydrogen source stream has about 1 mppm or less CO based upon the composition of the combined stream.

84. The process of claim 81, wherein a combined stream of the first propylene stream and the hydrogen source stream has about 1 mppm or less CO₂ based upon the composition of the combined stream.

85. The process of claim 80, wherein from about 1.5 moles to about 10 moles of hydrogen are present for every mole of byproducts in the first propylene stream.

86. The process of claim 81, wherein the hydrogen source stream is from a source selected from the group comprising pipeline hydrogen, hydrogen from reformed naphtha, hydrogen from refinery streams, hydrogen from bottled sources, hydrogen from water electrolysis reactors, hydrogen from refinery streams and hydrogen from decomposition of oxygenates.

87. The process of claim 80, wherein the first propylene stream is heated to a temperature ranging from about 100°

F. (38°

C.) to about 250°

F. (121°

C.).

88. The process of claim 80, wherein the step of (a) hydrogenating occurs at a pressure ranging from about 250 psia (1720 kPaa) to about 300 psia (2070 kPaa).

90. The process of claim 80, wherein the first catalyst and second catalyst are elemental palladium catalyst.

91. The process of claim 80, wherein the first propylene stream comprises about 90 mol. % or more propylene based upon the composition of the first propylene stream.

92. The process of claim 80, wherein the first propylene stream comprises about 500 mppm or less byproducts based upon the composition of the first propylene stream.

93. The process of claim 80, wherein the temperature of the second olefin stream ranges from about 100°

F. (38°

C.) to about 250°

F. (121°

C.).

94. The process of claim 80, wherein the step of (b) contacting occurs at a pressure ranging from about 250 psia (1720 kPaa) to about 300 psia (2070 kPaa).

95. A process for hydrogenating byproducts selected from the group consisting of alkynes, dienes and mixtures thereof in an olefin product stream from an oxygenate-to-olefin reactor, the process comprising the steps of:

(a) providing a first olefin stream comprising olefins selected from the group comprising ethylene, propylene and mixtures thereof and byproducts;

(b) adding excess hydrogen to the first olefin stream, the excess hydrogen being from a hydrogen source stream that has about 0.2 mol. % or less impurities selected from the group consisting of CO₂ and CO and has about 10 mol. % or less methane;

(c) hydrogenating the first olefin stream producing a hydrogenated olefin stream, wherein the hydrogenated olefin stream has about 20 mppm or less hydrogen based upon the composition of the hydrogenated olefin stream; and

(d) fractionating the hydrogenated olefin stream to remove methane.

96. The process of claim 95, wherein at least a portion of the hydrogen is from a hydrogen source stream having about 98 mol. % or more hydrogen based upon the composition of the hydrogen source stream.

97. The process of claim 96, wherein a combined stream of the first olefin stream and the hydrogen source stream has about 500 mppm or less methane based upon the composition of the combined stream.

98. The process of claim 96, wherein a combined stream of the first olefin stream and the hydrogen source stream has about 1 mppm or less CO based upon the composition of the combined stream.

99. The process of claim 96, wherein a combined stream of the first olefin stream and the hydrogen source stream has about 1 mppm or less CO₂ based upon the composition of the combined stream.

100. The process of claim 95, wherein from about 1.5 moles to about 10 moles of hydrogen are present for every mole of byproducts in the first olefin stream.

101. The process of claim 96, wherein the hydrogen source stream is from a source selected from the group comprising pipeline hydrogen, hydrogen from reformed naphtha, hydrogen from refinery streams, hydrogen from bottled sources, hydrogen from water electrolysis reactors, hydrogen from refinery streams and hydrogen from decomposition of oxygenates.

102. The process of claim 95, wherein the first olefin stream is heated to a temperature ranging from about 100°

F. (38°

C.) to about 250°

F. (121°

C.).

103. The process of claim 95, wherein the step of (a) hydrogenating occurs at a pressure ranging from about 50 psia (344 kPaa) to about 400 psia (2760 kPaa).

104. The process of claim 95, wherein the step of hydrogenating is done in the presence of a catalyst, the catalyst being an elemental Group VIII metal catalysts.

105. The process of claim 95, wherein the catalyst is elemental palladium catalyst.

106. The process of claim 95, wherein the first olefin stream contains about 99 mol. % or more olefin based upon the composition of the first olefin stream.

107. The process of claim 95, wherein the first olefin stream comprises about 90 mol. % or more ethylene based upon the composition of the first olefin stream.

108. The process of claim 95, wherein the byproducts include acetylene and the first olefin stream comprises about 500 mppm or less byproducts based upon the composition of the first olefin stream.

109. The process of claim 95, wherein the first olefin stream comprises about 90 mol. % or more propylene based upon the composition of the first olefin stream.

110. The process of claim 95, wherein the byproducts are selected from the group comprising methyl acetylene, propadiene and mixtures thereof and the first olefin stream comprises about 500 mppm or less byproducts based upon the composition of the first olefin stream.

111. The process of claim 95, wherein the temperature of the second olefin stream ranges from about 100°

F. (38°

C.) to about 250°

F. (121°

C.).

112. The process of claim 95, wherein the step of (b) contacting occurs at a pressure ranging from about 50 psia (344 kPaa) to about 400 psia (2760 kPaa).