Methods and apparatus for isolating carboxylic acid

Abstract

Disclosed are methods and apparatus for isolating a carboxylic acid. The processes employ a rotary pressure drum filter as a product isolation device in a carboxylic acid production process. The product isolation device is employed to isolate purified carboxylic acid particles from an isolation feed slurry comprising an aliphatic acid.

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 schematic representation of a rotary pressure drum filter that can be employed to isolate carboxylic acid from the liquid phase of a slurry produced by one or more oxidation reactors;

FIG. 2 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. 3 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 concentration zone;

FIG. 4 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 non-benzoic acid (non-BA) byproduct removal zone; and

FIG. 5 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 concentration, the resulting solvent rich stream is returned to the oxidation reactor and the resulting concentrated isolation feed slurry is subjected to product isolation.

Claims

1. A method for isolating purified particles comprising an aromatic dicarboxylic acid, said method comprising: treating an isolation feed slurry comprising said purified particles in a product isolation zone to thereby produce a wet cake comprising said aromatic dicarboxylic acid in an amount of at least about 10 weight percent, wherein said product isolation zone is defined within a rotary pressure drum filter, and wherein said slurry comprises an aliphatic acid in an amount of at least about 10 weight percent.

2. The method of claim 1, wherein said aliphatic acid comprises an aliphatic carboxylic acid having 1 to 6 carbon atoms.

3. The method of claim 1, wherein said aliphatic acid comprises acetic acid.

4. The method of claim 1, wherein said isolation feed slurry comprises said purified particles in an amount in the range of from about 1 to about 50 weight percent.

5. The method of claim 1, wherein said wet cake comprises said purified particles in an amount of at least about 70 weight percent.

6. The method of claim 1, wherein said purified particles have an average concentration of said aromatic dicarboxylic acid of at least about 50 weight percent.

7. The method of claim 1, wherein said purified particles are purified terephthalic acid (PTA) particles.

8. The method of claim 1, wherein said isolation feed slurry comprises a liquid phase comprising said aliphatic acid in an amount of at least about 60 weight percent.

9. The method of claim 8, wherein said liquid phase comprises said aliphatic acid in an amount of at least about 75 weight percent, wherein said liquid phase further comprises water.

10. The method of claim 1, further comprising, upstream of said product isolation zone, oxidizing an aromatic compound in an oxidation zone to thereby produce a crude slurry having a solids content of at least about 15 weight percent.

11. The method of claim 10, wherein said oxidizing is a precipitating reaction that causes at least about 10 weight percent of said aromatic compound to form solids in said oxidation zone.

12. The method of claim 10, wherein said aromatic compound comprises para-xylene.

13. The method of claim 10, further comprising subjecting a purification feed slurry comprising at least a portion of said crude slurry to oxidative digestion to thereby produce a purified slurry comprising said purified particles.

14. The method of claim 13, wherein said purification feed slurry comprises said aliphatic acid in an amount of at least about 10 weight percent.

15. The method of claim 13, wherein at least a portion of said purified slurry is employed as said isolation feed slurry.

16. The method of claim 1, further comprising introducing a wash feed stream into said product isolation zone to wash at least a portion of said wet cake to thereby produce a washed wet cake, wherein said wash stream comprises an aliphatic acid and/or water.

17. The method of claim 16, further comprising introducing a drying gas into said product isolation zone to thereby dry at least a portion of said washed wet cake.

18. A method for isolating purified terephthalic acid (PTA) particles, said method comprising: (a) introducing an isolation feed slurry comprising said PTA particles and a liquid phase into a product isolation zone;(b) removing at least a portion of said liquid phase to thereby produce a wet cake and a mother liquor; and(c) routing at least a portion of said mother liquor to a purge treatment zone, wherein said product isolation zone is defined within a rotary pressure drum filter, and wherein said liquid phase comprises an aliphatic acid in an amount of at least about 10 weight percent.

19. The method of claim 18, wherein said aliphatic acid comprises an aliphatic carboxylic acid having 1 to 6 carbon atoms.

20. The method of claim 18, wherein said aliphatic acid comprises acetic acid.

21. The method of claim 18, wherein said liquid phase comprises said aliphatic acid in an amount of at least about 60 weight percent.

22. The method of claim 18, wherein said isolation feed slurry comprises said PTA particles in an amount in the range of from about 1 to about 50 weight percent.

23. The method of claim 18, wherein said wet cake comprises said PTA particles in an amount of at least about 70 weight percent.

24. The method of claim 18, further comprising, upstream of said product isolation zone, oxidizing an aromatic compound in an oxidation zone to thereby produce a crude slurry having a solids content of at least about 15 weight percent.

25. The method of claim 24, wherein said oxidizing is a precipitating reaction that causes at least about 10 weight percent of said aromatic compound to form solids in said oxidation zone, wherein said aromatic compound comprises para-xylene.

26. The method of claim 24, further comprising subjecting said crude slurry to oxidative digestion to thereby produce said isolation feed slurry.

27. The method of claim 18, wherein said PTA particles have an average terephthalic acid concentration of at least about 50 weight percent.

28. The method of claim 18, wherein said mother liquor comprises one or more catalyst components comprising cobalt, manganese, and/or bromine, wherein said mother liquor comprises oxidation byproducts comprising benzoic acid (BA) and non-BA byproducts.

29. The method of claim 28, further comprising separating said portion of said mother liquor into a BA rich stream, a non-BA byproduct rich stream, and a catalyst rich stream in said purge treatment zone.

30. A process for producing purified terephthalic acid (PTA), said process comprising: (a) oxidizing an aromatic compound in an oxidation zone to thereby produce a crude slurry comprising crude terephthalic acid (CTA) particles;(b) subjecting at least a portion of said crude slurry to purification to thereby produce a purified slurry comprising PTA particles, oxidation byproducts, and an aliphatic acid in an amount of at least about 10 weight percent; and(c) isolating at least a portion of said PTA particles from said purified slurry in a product isolation zone to thereby produce a PTA product, wherein said product isolation zone is defined within a rotary pressure drum filter, wherein the cumulative rate at which said oxidation byproducts exit said PTA production process with said PTA product and/or are combined with said PTA product downstream of said PTA production process is at least about 15 percent of the net make rate of said oxidation byproducts in said PTA production process.

31. The process of claim 30, wherein said aliphatic acid comprises an aliphatic carboxylic acid having 1 to 6 carbon atoms.

32. The process of claim 30, wherein said aliphatic acid comprises acetic acid.

33. The process of claim 30, wherein said purified slurry comprises a liquid phase, wherein said liquid phase comprises said aliphatic acid in an amount of at least about 60 weight percent.

34. The process of claim 30, wherein the cumulative rate at which said oxidation byproducts exit said PTA production process with said PTA product and/or are combined with said PTA product downstream of said PTA production process is at least about 40 percent of the net make rate of said oxidation byproducts in said PTA production process.

35. The process of claim 30, wherein said oxidizing of step (a) comprises a precipitating oxidation reaction that forms said CTA particles.

36. The process of claim 35, wherein said aromatic compound comprises para-xylene, wherein said precipitating oxidation reaction causes at least about 10 weight percent of said para-xylene to form solids in said oxidation zone.

37. The process of claim 30, wherein said isolating of step (c) further produces a mother liquor comprising a solvent, one or more catalyst components, and oxidation byproducts, wherein said oxidation byproducts comprise benzoic acid (BA) and non-BA byproducts.

38. The process of claim 37, further comprising treating at least a portion of said mother liquor in a concentration zone to thereby produce a catalyst and oxidation byproduct rich stream and a solvent rich stream.

39. The process of claim 38, further comprising directly or indirectly routing at least a portion of said solvent rich stream to said oxidation zone, and/or directly or indirectly routing at least a portion of said catalyst and oxidation byproduct rich stream to a purification zone where said purification of step (b) is carried out and/or to said product isolation zone.

40. The process of claim 37, further comprising treating at least a portion of said mother liquor in a non-BA byproduct removal zone to thereby produce a non-BA byproduct rich stream, a solvent rich stream, and a catalyst and BA rich stream.

41. The process of claim 40, further comprising directly or indirectly routing at least a portion of said solvent rich stream and/or at least a portion of said catalyst and BA rich stream to said oxidation zone, and/or routing at least a portion of said non-BA byproduct rich stream to one or more locations that causes at least a portion of said non-BA byproducts present in said non-BA byproduct rich stream to be combined with said PTA product downstream of said PTA production process.

42. A method for treating a purified slurry comprising purified terephthalic acid (PTA) particles, said method comprising: treating said purified slurry in a catalyst removal zone to thereby produce a wet cake comprising at least a portion of said PTA particles and a mother liquor, wherein said slurry comprises said PTA particles in an amount of at least about 15 weight percent, wherein said slurry comprises acetic acid, and wherein said catalyst removal zone is defined within a rotary pressure drum filter.

43. The method of claim 42, wherein said purified slurry comprises oxidation byproducts produced in a terephthalic acid (TPA) production process.

44. The method of claim 43, wherein said oxidation byproducts exit said TPA production process with said wet cake at substantially the same rate as the make rates of said oxidation byproducts in said TPA production process.

45. The method of claim 43, further comprising routing at least a portion of said mother liquor to an oxidation section where at least a portion of said oxidation byproducts are formed.

46. The method of claim 42, wherein said mother liquor comprises a solvent comprising acetic acid and/or water.

47. The method of claim 46, further comprising concentrating at least a portion of said purified slurry in a concentration section prior to said treating in said catalyst removal zone and/or treating at least a portion of said mother liquor in a concentration section to thereby produce a solvent rich stream and a concentrated stream.

48. The method of claim 47, further comprising routing at least a portion of said concentrated stream to a post-oxidation section where at least a portion of said PTA particles are formed and/or routing at least a portion of said concentrated stream to said catalyst removal zone.

49. The method of claim 42, further comprising subjecting a crude slurry comprising crude terephthalic acid (CTA) particles to oxidative digestion to thereby produce said purified slurry.

50. The method of claim 42, further comprising introducing a wash stream into said catalyst removal zone to wash at least a portion of said wet cake thereby producing a washed wet cake and a wash liquor.