Versatile oxidation byproduct purge process

Abstract

Disclosed is a process and apparatus for treating a purge stream in a carboxylic acid production process. The process employs a purge process that allows for the separation of oxidation byproducts into benzoic acid and non-benzoic acid oxidation byproducts, thus providing flexibility in the treatment and use of such oxidation byproducts.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

A preferred embodiment of the present invention is described in detail below with reference to the attached drawing figures, wherein:

FIG. 1 is a process flow diagram illustrating a system for the production and purification of carboxylic acid constructed in accordance with the present invention, particularly illustrating a configuration where the crude slurry from the oxidation reactor is subjected to purification, the resulting purified slurry is subjected to product isolation, and a portion of the mother liquor from the product isolation zone is employed as a feed to a purge treatment system;

FIG. 2 is a process flow diagram illustrating an overview of a purge treatment system constructed in accordance with a first embodiment of the present invention, particularly illustrating a configuration where the purge feed stream is subjected to non-benzoic acid (non-BA) byproduct removal and the resulting catalyst and benzoic acid (BA) rich mother liquor is subjected to BA removal;

FIG. 3 is a process flow diagram illustrating in detail a purge treatment system constructed in accordance with a first configuration of the first embodiment of the present invention, particularly illustrating a configuration where the purge feed stream is subjected to concentration, the resulting concentrated purge stream is subjected to solid/liquid separation, the resulting catalyst and BA rich mother liquor is subjected to concentration, and the resulting concentrated catalyst and BA rich mother liquor is subjected to BA/catalyst separation;

FIG. 4 is a process flow diagram illustrating in detail a purge treatment system constructed in accordance with a second configuration of the first embodiment of the present invention, particularly illustrating a configuration where the purge feed stream is subjected to concentration, the resulting concentrated purge stream is subjected to solid/liquid separation, the resulting catalyst and BA rich mother liquor is subjected to catalyst removal, and the resulting BA and solvent rich stream is subjected to BA/solvent separation;

FIG. 5 is a process flow diagram illustrating an overview of a purge treatment system constructed in accordance with a second embodiment of the present invention, particularly illustrating a configuration where the purge feed stream is subjected to BA removal and the resulting catalyst and non-BA byproduct rich stream is subjected to non-BA byproduct removal; and

FIG. 6 is a process flow diagram illustrating in detail a purge treatment system constructed in accordance with the second embodiment of the present invention, particularly illustrating a configuration where the purge feed stream is subjected to concentration, the resulting concentrated purge stream is subjected to BA separation, the resulting catalyst and non-BA byproduct rich stream is reslurried, and the reslurried catalyst and non-BA byproduct rich stream is subjected to solid/liquid separation.

Claims

1. A process for treating a purge feed stream comprising oxidation byproducts, wherein said oxidation byproducts include benzoic acid (BA) and non-BA byproducts, said process comprising: separating at least a portion of said purge feed stream into a BA rich stream and a non-BA byproduct rich stream.

2. The process of claim 1, further comprising routing at least a portion of said BA rich stream and at least a portion of said non-BA byproduct rich stream to different locations.

3. The process of claim 2, wherein said oxidation byproducts are produced in a terephthalic acid (TPA) production process.

4. The process of claim 3, wherein said routing includes directing at least a portion of said non-BA byproduct rich stream to one or more locations that cause at least about 5 weight percent of said non-BA byproducts present in said non-BA byproduct rich stream to exit said TPA production process with a TPA product produced therein and/or to be combined with said TPA product downstream of said TPA production process.

5. The process of claim 3, wherein said routing includes introducing at least a portion of said non-BA byproduct rich stream into said TPA production process at one or more locations that cause at least a portion of said non-BA byproducts present in said non-BA byproduct rich stream to exit said TPA production process with a TPA product produced therein.

6. The process of claim 5, wherein at least about 10 weight percent of said non-BA byproducts present in said non-BA byproduct rich stream exits said TPA production process with said TPA product.

7. The process of claim 3, wherein said routing includes directing at least a portion of said BA rich stream outside said TPA production process for sale, waste treatment, disposal, purification, recovery, destruction, and/or use in a subsequent chemical process.

8. The process of claim 7, wherein at least about 50 weight percent of said BA present in said BA rich stream is treated in a waste treatment process.

9. The process of claim 2, wherein said different locations include various points in a TPA production process, an isophthalic acid (IPA) production process, a phthalic acid (PA) production process, a BA production process, a naphthalene-dicarboxylic acid (NDA) production process, a dimethylterephthalate (DMT) production process, a dimethylnaphthalate (DMN) production process, a cyclohexane dimethanol (CHDM) production process, a dimethyl-cyclohexanedicarboxylate (DMCD) production process, a cyclohexanedicarboxylic acid (CHDA) production process, a polyethylene terephthalate (PET) production process, a copolyester production process, a polymer production process employing one or more of TPA, IPA, PA, BA, NDA, DMT, DMN, CHDM, DMCD, or CHDA as one component and/or as a monomer, and/or outside said TPA, IPA, PA, BA, NDA, DMT, DMN, CHDM, DMCD, CHDA, or polymer production processes.

10. The process of claim 1, wherein said purge feed stream comprises less than about 5 weight percent solids.

11. The process of claim 1, wherein said non-BA byproduct rich stream comprises at least about 70 weight percent solids.

12. The process of claim 1, wherein said BA rich stream comprises at least about 70 weight percent fluid.

13. The process of claim 1, wherein said non-BA byproduct rich stream comprises in the range of from about 5 to about 40 weight percent liquid.

14. The process of claim 13, further comprising drying said non-BA byproduct rich stream to thereby produce a dried non-BA byproduct stream comprising less than about 5 weight percent liquid.

15. The process of claim 13, further comprising adding a liquid to said non-BA byproduct rich stream to thereby produce a reslurried non-BA byproduct stream comprising at least about 35 weight percent liquid.

16. The process of claim 1, wherein at least a portion of said oxidation byproducts are byproducts from the partial oxidation of an aromatic compound.

17. The process of claim 16, wherein said aromatic compound is para-xylene.

18. The process of claim 1, wherein said non-BA byproducts comprise IPA, PA, trimellitic acid, 2,5,4′-tricarboxybiphenyl, 2,5,4′-tricarboxybenzophenone, para-toluic acid (p-TAc), 4-carboxybenzaldehyde (4-CBA), naphthalene dicarboxylic acid, monocarboxyfluorenones, monocarboxyfluorenes, and/or dicarboxyfluorenones.

19. The process of claim 1, wherein the concentration of said BA in said BA rich stream is at least about 1.5 times the concentration of said BA in said purge feed stream on a weight basis.

20. The process of claim 19, wherein the concentration of said BA in said purge feed stream is in the range of from about 500 to about 150,000 ppmw.

21. The process of claim 1, wherein the concentration of said non-BA byproducts in said non-BA byproduct rich stream is at least about 1.5 times of the concentration of said non-BA byproducts in said purge feed stream on a weight basis.

22. The process of claim 21, wherein the cumulative concentration of said non-BA byproducts in said purge feed stream is in the range of from about 500 to about 50,000 ppmw.

23. The process of claim 1, wherein the concentration of said BA in said BA rich stream is at least about 5 times the concentration of said BA in said purge feed stream on a weight basis, wherein the concentration of said non-BA byproducts in said non-BA byproduct rich stream is at least about 5 times the concentration of said non-BA byproducts in said purge feed stream on a weight basis.

24. The process of claim 1, wherein said purge feed stream further comprises at least about 75 weight percent of a solvent.

25. The process of claim 24, wherein said solvent comprises a monocarboxylic acid.

26. The process of claim 24, wherein said solvent comprises acetic acid and/or water.

27. The process of claim 24, further comprising directly or indirectly routing at least a portion of said solvent back to an oxidizer within which at least a portion of said oxidation byproducts are formed.

28. The process of claim 27, wherein at least about 50 weight percent of said solvent contained in said purge feed stream is routed back to said oxidizer.

29. The process of claim 1, wherein said purge feed stream further comprises one or more catalyst components.

30. The process of claim 29, wherein said catalyst components comprise cobalt, manganese, and/or bromine.

31. The process of claim 29, further comprising separating said purge feed stream into said BA rich stream, said non-BA byproduct rich stream, and a catalyst rich stream.

32. The process of claim 31, further comprising routing at least a portion of said BA rich stream, at least a portion of said non-BA byproduct rich stream, and at least a portion of said catalyst rich stream to at least two different locations.

33. The process of claim 32, wherein said oxidation byproducts are produced in a TPA production process.

34. The process of claim 33, wherein said routing includes introducing at least a portion of said catalyst rich stream into an oxidizer of said TPA process within which at least a portion of said oxidation byproducts were formed.

35. The process of claim 34, wherein at least about 50 weight percent of said catalyst components in said catalyst rich stream are introduced into said oxidizer.

36. The process of claim 31, wherein the cumulative concentration of all of said catalyst components in said catalyst rich stream is at least about 1.5 times the concentration of said catalyst components in said purge feed stream on a weight basis.

37. The process of claim 36, wherein the cumulative concentration of said catalyst components in said purge feed stream is in the range of from about 500 to about 20,000 ppmw.

38. The process of claim 31, wherein the cumulative concentration of all of said catalyst components in said catalyst rich stream is at least about 5 times the concentration of said catalyst components in said purge feed stream on a weight basis, wherein the concentration of said BA in said BA rich stream is at least about 5 times the concentration of said BA in said purge feed stream on a weight basis, wherein the concentration of said non-BA byproducts in said non-BA byproduct rich stream is at least about 5 times the concentration of non-BA byproducts in said purge feed stream on a weight basis.

39. The process of claim 31, wherein said separating includes separating said purge feed stream into said non-BA byproduct rich stream and a catalyst and BA rich stream followed by separating said catalyst and BA rich stream into said BA rich stream and a catalyst rich stream.

40. The process of claim 31, wherein said separating includes separating said purge feed stream into said BA rich stream and a catalyst and non-BA byproduct rich stream followed by separating said catalyst and non-BA byproduct rich stream into said non-BA byproduct rich stream and a catalyst rich stream.

41. A terephthalic acid (TPA) production process comprising: (a) oxidizing an aromatic compound to thereby produce a slurry comprising TPA and oxidation byproducts, wherein said oxidation byproducts include benzoic acid (BA) and non-BA byproducts; and(b) substantially isolating said TPA from said slurry to thereby produce a TPA product, wherein the cumulative rate at which said non-BA byproducts exit said TPA production process with said TPA product and/or are combined with said TPA product downstream of said TPA production process is at least about 5 percent of the make-rate of said non-BA byproducts in said TPA production process.

42. The process of claim 41, wherein the rate at which said BA exits said TPA production process with said TPA product and/or is combined with said TPA product downstream of said TPA production process is less than about 50 percent of the make-rate of said BA in said TPA production process.

43. The process of claim 41, wherein the cumulative rate at which said non-BA byproducts exit said TPA production process with said TPA product and/or are combined with said TPA product downstream of said TPA production process is at least about 10 percent the make-rate of said non-BA byproducts in said TPA production process.

44. The process of claim 41, wherein said isolating of step (b) comprises subjecting said purified slurry to solid/liquid separation to thereby produce a predominately solid phase stream comprising at least a portion of said TPA product and a mother liquor, wherein said mother liquor comprises at least a portion of said oxidation byproducts and one or more catalyst components.

45. The process of claim 44, said process further comprising directly or indirectly routing a first portion of said mother liquor to an oxidizer where said oxidizing of step (a) is carried out.

46. The process of claim 44, said process further comprising diverting a second portion of said mother liquor so as to form a purge feed stream and separating said purge feed stream into a BA rich stream, a non-BA byproduct rich stream, and a catalyst rich stream.

47. The process of claim 46, further comprising routing at least a portion of said BA rich stream, at least a portion of said non-BA byproduct rich stream, and at least a portion of said catalyst rich stream to at least two different locations.

48. The process of claim 47, wherein said routing includes introducing at least a portion of said catalyst rich stream into an oxidizer where said oxidizing of step (a) is carried out.

49. The process of claim 47, wherein said routing includes introducing at least a portion of said non-BA byproduct rich stream into said TPA production process at one or more locations that cause at least a portion of said non-BA byproducts present in said non-BA byproduct rich stream to exit said TPA production process with said TPA product.

50. The process of claim 47, wherein said routing includes introducing at least a portion of said non-BA byproduct rich stream into said slurry and/or said TPA product.

51. The process of claim 47, wherein said routing includes directing at least a portion of said BA rich stream outside said TPA production process for sale, waste treatment, disposal, purification, recovery, destruction, and/or use in a subsequent chemical process.

52. The process of claim 46, wherein said purge feed stream comprises less than about 5 weight percent solids, wherein said catalyst rich stream comprises at least about 70 weight percent solids, wherein said BA rich stream comprises at least about 70 weight percent liquid, wherein said non-BA byproduct rich stream comprises in the range of from about 5 to about 30 weight percent liquid.

53. The process of claim 46, wherein the concentration of said BA in said BA rich stream is at least about 1.5 times the concentration of said BA in said purge feed stream on a weight basis, wherein the concentration of said non-BA byproducts in said non-BA byproduct rich stream is at least about 1.5 times of the concentration of said non-BA byproducts in said purge feed stream on a weight basis, wherein the concentration of said catalyst components in said catalyst rich stream is at least about 1.5 times the concentration of said catalyst components in said purge feed stream on a weight basis.

54. The process of claim 41, step (a) further comprising subjecting at least a portion of said slurry to purification to thereby produce a purified slurry comprising at least a portion of said TPA and at least a portion of said oxidation byproducts.

55. The process of claim 54, wherein said purification comprises hydrogenation and/or oxidation.

56. The process of claim 41, wherein said non-BA byproducts comprise IPA, PA, trimellitic acid, 2,5,4′-tricarboxybiphenyl, 2,5,4′-tricarboxybenzophenone, p-TAc, 4-CBA, naphthalene dicarboxylic acid, monocarboxyfluorenones, monocarboxyfluorenes, and/or dicarboxyfluorenones.

57. The process of claim 41, wherein said TPA product comprises a cumulative concentration of mono-functional oxidation byproducts of less than about 1,000 ppmw.

58. The process of claim 57, wherein said mono-functional oxidation byproducts comprise BA, 4-CBA, p-TAc, monocarboxyfluorenones, monocarboxyfluorenes, bromo-benzoic acid, and/or bromo-acetic acid.

59. A process for treating a purge feed stream comprising impurities and one or more catalyst components, said process comprising: separating said purge feed stream into a mono-functional impurity rich stream, a mono-functional impurity depleted stream, and a catalyst rich stream.

60. The process of claim 59, wherein said impurities include oxidation byproducts.

61. The process of claim 60, wherein said oxidation byproducts include benzoic acid, isophthalic acid, p-toluic acid (p-TAc), and/or 4-carboxybenzaldehyde.

62. The process of claim 59, wherein said purge feed stream further comprises solvent, water, and/or terephthalic acid.

63. The process of claim 59, wherein said purge feed stream comprises less than about 5 weight percent solids.

64. The process of claim 59, wherein said impurities comprise mono-functional impurities and non-mono-functional impurities, wherein said mono-functional impurities comprise at least one monocarboxylic species.

65. The process of claim 64, wherein said mono-functional impurities comprise benzoic acid, p-TAc, monocarboxyfluorenones, monocarboxyfluorenes, bromo-benzoic acid, and/or bromo-acetic acid.

66. The process of claim 60, wherein benzoic acid (BA) is the primary oxidation byproduct present in said mono-functional impurity rich stream.

67. The process of claim 60, wherein non-BA oxidation byproducts are the primary oxidation byproducts present in said mono-functional impurity depleted stream.

68. The process of claim 67, wherein said non-BA oxidation byproducts include isophthalic acid and/or trimellitic acid.

69. The process of claim 59, wherein said catalyst components comprise cobalt, manganese, and/or bromine.

70. The process of claim 59, further comprising routing at least a portion of said mono-functional impurity rich stream, at least a portion of said mono-functional impurity depleted stream, and at least a portion of said catalyst rich stream to at least two different locations.

71. The process of claim 70, wherein said impurities are produced in a terephthalic acid (TPA) production process.

72. The process of claim 71, wherein said routing includes directing at least a portion of said mono-functional impurity rich stream outside said TPA production process for sale, waste treatment, disposal, and/or destruction.

73. The process of claim 71, wherein non-mono-functional oxidation byproducts are the primary oxidation byproducts present in said mono-functional impurity depleted stream, wherein said routing includes directing at least a portion of said mono-functional impurity depleted stream to one or more locations that cause a substantial portion of said non-mono-functional oxidation byproducts present in said mono-functional impurity depleted stream to exit said TPA production process with a TPA product produced therein and/or to be combined with said TPA product downstream of said TPA production process.

74. The process of claim 73, wherein said TPA product comprises a cumulative concentration of mono-functional oxidation byproducts of less than about 1,000 ppmw.

75. The process of claim 70, wherein said routing includes introducing at least a portion of said catalyst rich stream into an oxidizer within which said impurities are formed.

76. The process of claim 70, wherein said different locations include various points in a polymer production process employing terephthalic acid as one component and/or as a monomer, said TPA production process, a polyethylene terephthalate (PET) production process, and/or outside said polymer, TPA, or PET production processes.