Carboxylic acid production process

Abstract

Disclosed are processes and apparatus for producing a carboxylic acid. The processes employ a concentration section disposed before and/or after a product isolation section, which allows for oxidation byproducts produced in the process to exit the product isolation section with the isolated carboxylic acid product and/or to be combined with the isolated carboxylic acid product downstream of the product isolation section at a rate of at least about 15 percent of the net make rate of the oxidation byproducts in the production process.

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 a first embodiment of 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 displaced oxidation solvent from the purification zone and a portion of the mother liquor from the product isolation zone are employed as feeds to a concentration zone;

FIG. 2 is a process flow diagram illustrating a system for the production and purification of carboxylic acid constructed in accordance with a second embodiment of 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 displaced oxidation solvent from the purification zone and a portion of the mother liquor from the product isolation zone are employed as feeds to a non-BA byproduct removal zone;

FIG. 3 is a process flow diagram illustrating in detail a non-BA byproduct removal zone constructed in accordance with the second embodiment of the present invention, particularly illustrating a configuration where the displaced oxidation solvent and the purified byproduct removal feed are subjected to concentration, and the resulting concentrated stream is subjected to solid/liquid separation; and

FIG. 4 is a process flow diagram illustrating a system for the production and purification of carboxylic acid constructed in accordance with a third embodiment of 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 concentration, the resulting solvent rich stream is returned to the oxidation reactor and the concentrated isolation feed slurry is subjected to product isolation.

Claims

1. A carboxylic acid production process comprising: (a) treating a concentration feed stream comprising a solvent and solids in a concentration zone to thereby produce a solvent rich stream and a concentrated isolation feed stream comprising at least a portion of said solids; and(b) isolating at least a portion of said solids from at least a portion of said concentrated isolation feed stream in a product isolation zone to thereby produce a mother liquor and an isolated product comprising isolated solids, wherein said isolated solids comprise carboxylic acid particles and oxidation byproducts, wherein said oxidation byproducts are formed in said production process, wherein the rate at which said oxidation byproducts exit said product isolation zone with said isolated solids is at least about 15 percent of the net make rate of said oxidation byproducts in said production process.

2. The process of claim 1, wherein the rate at which said oxidation byproducts exit said product isolation zone with said isolated solids is at least about 40 percent of the net make rate of said oxidation byproducts in said production process.

3. The process of claim 1, wherein the rate at which said oxidation byproducts exit said product isolation zone with said isolated solids is at least about 60 percent of the net make rate of said oxidation byproducts in said production process.

4. The process of claim 1, wherein the net make rate of said oxidation byproducts in said process is at least about 5 kg/hour.

5. The process of claim 1, wherein the net make rate of said oxidation byproducts in said process is in the range of from about 5 to about 20,000 kg/hour.

6. The process of claim 1, wherein said isolated product comprises said oxidation byproducts in an amount in the range of from about 1,000 to about 100,000 ppmw.

7. The process of claim 1, wherein said mother liquor comprises at least a portion of said oxidation byproducts, one or more catalyst components, and a solvent.

8. The process of claim 7, wherein less than about 85 weight percent of said oxidation byproducts in said mother liquor are purged from said production process.

9. The process of claim 1, wherein no purge process is employed in said production process.

10. The process of claim 1, wherein substantially all of said oxidation byproducts entering said product isolation zone exit said product isolation zone with said isolated product and/or are returned, either directly or indirectly, to a point in said production process upstream of said product isolation zone.

11. The process of claim 1, wherein said concentrated isolation feed stream comprises a concentration of oxidation byproducts that is at least about 1.05 times the concentration of oxidation byproducts in said concentration feed stream.

12. The process of claim 1, wherein said concentrated isolation feed stream comprises a concentration of said solids that is at least about 1.05 times the concentration of said solids in said concentration feed stream.

13. The process of claim 1, wherein said concentrated isolation feed stream comprises said solids in an amount in the range of from about 20 to about 70 weight percent.

14. The process of claim 1, further comprising subjecting an aromatic compound to oxidation in an oxidation zone to thereby produce a crude product stream comprising crude carboxylic acid particles and at least a portion of said oxidation byproducts.

15. The process of claim 14, wherein said aromatic compound comprises para-xylene.

16. The process of claim 14, wherein at least a portion of said crude product stream is employed as said concentration feed stream.

17. The process of claim 14, further comprising subjecting at least a portion of said crude product stream to purification in a purification zone to thereby produce a purified product stream comprising purified carboxylic acid particles and at least a portion of said oxidation byproducts.

18. The process of claim 17, wherein said purification comprises hydrogenation and/or oxidation.

19. The process of claim 17, wherein at least a portion of said purified product stream is employed as said concentration feed stream.

20. The process of claim 17, wherein said purification further produces a displaced oxidation solvent stream.

21. The process of claim 20, further comprising directly or indirectly routing at least a portion of said displaced oxidation solvent stream to said oxidation zone.

22. The process of claim 14, further comprising directly or indirectly routing at least a portion of said mother liquor to said oxidation zone.

23. The process of claim 14, further comprising directly of indirectly routing at least a portion of said solvent rich stream to said oxidation zone.

24. The process of claim 1, wherein said oxidation byproducts comprise isophthalic acid (IPA), phthalic acid (PA), trimellitic acid, 2,5,4′-tricarboxybiphenyl, 2,5,4′-tricarboxybenzophenone, benzoic acid (BA), bromo-benzoic acid, bromo-acetic acid, para-toluic acid (p-TAc), 4-carboxybenzaldehyde (4-CBA), naphthalene dicarboxylic acid, monocarboxyfluorenones, monocarboxyfluorenes, and/or dicarboxyfluorenones, wherein said solvent comprises acetic acid and/or water.

25. The process of claim 1, further comprising introducing a wash stream into said product isolation zone to wash at least a portion of said isolated solids thereby producing a washed isolated product and a wash liquor.

26. The process of claim 1, further comprising introducing at least a portion of said isolated product into a drying zone to thereby produce a dried isolated product comprising less than about 5 weight percent liquid.

27. The process of claim 1, further comprising introducing at least a portion of said isolated product into a solvent swap zone to thereby produce an isolated product wet cake comprising in the range of from about 5 to about 30 weight percent liquid.

28. The process of claim 1, wherein said carboxylic acid comprises terephthalic acid.

29. A terephthalic acid production process comprising: (a) oxidizing an aromatic compound in an oxidation zone to thereby produce a crude product stream;(b) purifying at least a portion of said crude product stream in a purification zone to thereby produce a purified product stream comprising solvent and solid particles comprising terephthalic acid and oxidation byproducts;(c) concentrating at least a portion of said purified product stream in a concentration zone to thereby produce a concentrated isolation feed stream comprising at least a portion of said solid particles; and(d) treating said at least a portion of said concentrated isolation feed stream in a product isolation zone to thereby produce a mother liquor and an isolated product comprising at least a portion of said solid particles, wherein substantially all of said oxidation byproducts entering said product isolation zone exit said product isolation zone with said isolated product and/or are returned, either directly or indirectly, to a point in said production process upstream of said product isolation zone.

30. The process of claim 29, wherein the rate at which said oxidation byproducts exit said product isolation zone with said solid particles is at least about 15 percent of the net make rate of said oxidation byproducts in said production process.

31. The process of claim 29, wherein the net make rate of said oxidation byproducts in said process is at least about 5 kg/hour.

32. The process of claim 29, wherein the net make rate of said oxidation byproducts in said process is in the range of from about 5 to about 20,000 kg/hour.

33. The process of claim 29, wherein said isolated product comprises said oxidation byproducts in an amount in the range of from about 1,000 to about 100,000 ppmw.

34. The process of claim 29, further comprising directly or indirectly routing at least a portion of said mother liquor to said oxidation zone.

35. The process of claim 29, wherein said concentrating of step (c) further produces a solvent rich stream.

36. The process of claim 35, further comprising directly or indirectly routing at least a portion of said solvent rich stream to said oxidation zone.

37. The process of claim 35, wherein said solvent rich stream comprises a concentration of solvent that is at least about 1.1 times the concentration of said solvent in said purified product stream.

38. The process of claim 29, wherein said concentrated isolation feed stream comprises a concentration of oxidation byproducts that is at least about 1.05 times the concentration of oxidation byproducts in said purified product stream.

39. The process of claim 29, wherein said concentrated isolation feed stream comprises a concentration of said solid particles that is at least about 1.05 times the concentration of said solid particles in said purified product stream.

40. The process of claim 29, wherein said concentrated isolation feed stream comprises solids in an amount in the range of from about 20 to about 70 weight percent.

41. A terephthalic acid production process comprising: (a) oxidizing an aromatic compound in an oxidation section to thereby produce a crude terephthalic acid stream;(b) treating at least a portion of said crude terephthalic acid stream in a post-oxidation section to thereby produce a purified terephthalic acid stream comprising solvent, solid particles of purified terephthalic acid, and oxidation byproducts;(c) concentrating at least a portion of said purified terephthalic acid stream in a concentration section to thereby produce a concentrated stream; and(d) treating at least a portion of said concentrated stream in a catalyst removal section to thereby produce a mother liquor stream and a terephthalic acid product, wherein the rate at which said oxidation byproducts exit said process with said terephthalic acid product is substantially the same as the make rate of said oxidation byproducts in said process.

42. The process of claim 41, wherein none of said oxidation byproducts are purged from said production process.

43. The process of claim 41, wherein said oxidation byproducts comprise p-toluic acid, 4-carboxybenzaldehyde, trimellitic acid, benzoic acid, bromo-benzoic acid, bromo-acetic acid, monocarboxyfluorenones, 2,5,4′-tricarboxybiphenyl, and 2,5,4′-tricarboxybenzophenone, wherein said aromatic compound comprises para-xylene.

44. The process of claim 41, further comprising routing at least a portion of said mother liquor to said oxidation section.

45. The process of claim 41, wherein said treating of step (b) comprises oxidation and/or hydrogenation.

46. The process of claim 41, wherein said concentrated stream comprises in the range of from about 20 to about 70 weight percent solids.

47. The process of claim 41, wherein said concentrating of step (c) comprises removing at least a portion of said solvent from said purified terephthalic acid stream thereby producing a solvent stream.

48. The process of claim 47, further comprising routing at least a portion of said solvent stream to said oxidation zone, wherein said solvent comprises acetic acid and/or water.

49. The process of claim 41, wherein said treating of step (d) further comprises introducing a wash stream into said catalyst removal zone to wash at least a portion of said terephthalic acid product thereby producing a washed terephthalic acid product and a wash liquor.

50. The process of claim 49, further comprising routing at least a portion of said wash liquor to said oxidation section.