Process to produce an enrichment feed
View Patent ↗A process is provided for producing an enriched carboxylic acid compositions produced by contacting composition comprising a carboxylic acid with an enrichment feed in an enrichment zone to form an enriched carboxylic acid composition. This invention also relates to a process and the resulting compositions for removing catalyst from a carboxylic acid composition to produce a post catalyst removal composition.
1. A process to produce an enrichment feed, said process comprising:
(a) subjecting a solvent rich stream produced in a terephthalic acid production process to a solids concentration zone to form a concentrated solvent rich stream; wherein said solvent rich stream comprises at least one solvent, at least one carboxylic acid, and at least one oxidation byproduct; wherein said solvent rich stream has a solids content of less than 5% by weight; wherein the quantity of solids in said concentrated solvent rich stream is higher than the quantity of solids from said solvent rich stream on a weight basis;
(b) subjecting said concentrated solvent rich stream to a concentrated SLS zone (a solid-liquid separation zone) to form a mother liquor stream and an enrichment feed; wherein said concentrated SLS zone comprises at least one solid liquid separation device; and
(c) recycling at least a portion of said enrichment feed to any point in a TPA production process after a primary oxidation zone and before a drying zone.
2. The process according to claim 1 wherein said solid liquid separation device is a candle filter.
3. The process according to claim 2 wherein said enrichment feed is recycled such that an increase of b* in the TPA product is less than 2 compared to a TPA production process with no enrichment feed.
4. The process according to claim 2 wherein said enrichment feed is recycled such that an increase of b* in the TPA product is less than 4 compared to a TPA production process with no enrichment feed.
5. The process according to claim 3 wherein said concentrated solvent rich stream has a solids content ranging from about 0.5% by weight to about 45% by weight.
6. The process according to claim 3 wherein said concentrated solvent rich stream has a solids content ranging from about 1% by weight to about 30% by weight.
7. The process according to claim 2 wherein said concentrated solvent rich stream has a solids content ranging from about 0.5% by weight to about 45% by weight.
8. The process according to claim 2 wherein said concentrated solvent rich stream has a solids content ranging from about 1% by weight to about 30% by weight.
9. A process to produce an enrichment feed, said process comprising:
(a) subjecting an solvent rich stream produced in a terephthalic acid production process to a cooling and/or concentration zone to form a concentrated solvent rich stream; wherein said solvent rich stream comprises at least one solvent, at least one catalyst, at least one carboxylic acid, and at least one oxidation byproduct; wherein said solvent rich stream has a solids content of less than 5% by weight; wherein the quantity of solids in said concentrated solvent rich stream is higher than the quantity of solids from said solvent rich stream on a weight basis;
(b) subjecting said concentrated solvent rich stream to a concentrated SLS zone to form a mother liquor stream and an enrichment feed; wherein said concentrated SLS zone comprises at least one solid liquid separation device; and
(c) recycling at least a portion of said enrichment feed to any point in a TPA production process after a crystallization zone and before a drying zone.
10. The process according to claim 9 wherein said solid liquid separation device is a candle filter.
11. The process according to claim 10 wherein said enrichment feed is recycled such that an increase of b* in the TPA product is less than 2 compared to a TPA production process with no enrichment feed.
12. The process according to claim 11 wherein said concentrated solvent rich stream has a solids content ranging from about 10% by weight to about 45% by weight.
13. The process according to claim 11 wherein said concentrated solvent rich stream has a solids content ranging from about 10% by weight to about 30% by weight.
14. The process according to claim 9 wherein said concentrated solvent rich stream has a solids content ranging from about 10% by weight to about 45% by weight.
15. The process according to claim 9 wherein said concentrated solvent rich stream has a solids content ranging from about 10% by weight to about 30% by weight.
16. A process to produce an enrichment feed, said process comprising:
(a) subjecting an solvent rich stream produced in a terephthalic acid production process to a solids concentration zone to form a concentrated solvent rich stream; wherein said solvent rich stream comprises at least one solvent, at least one catalyst, at least one carboxylic acid, and at least one oxidation byproduct; wherein said solvent rich stream has a solids content of less than 1% by weight; wherein the quantity of solids in said concentrated solvent rich stream is higher than the quantity of solids from said solvent rich stream on a weight basis;
(b) subjecting said concentrated solvent rich stream to a concentrated SLS zone to form a mother liquor stream and an enrichment feed; wherein said concentrated SLS zone comprises at least one solid liquid separation device; and
(c) recycling at least a portion of said enrichment feed to any point in a TPA production process after a crystallization zone and before a drying zone.
17. The process according to claim 16 wherein said solid liquid separation device is a candle filter.
18. The process according to claim 17 wherein said enrichment feed is recycled such that an increase of b* in the TPA product is less than 2 compared to a TPA production process with no enrichment feed.
19. The process according to claim 18 wherein said concentrated solvent rich stream has a solids content ranging from about 10% by weight to about 45% by weight.
20. The process according to claim 18 wherein said concentrated solvent rich stream has a solids content ranging from about 10% by weight to about 30% by weight.
21. The process according to claim 16 wherein said concentrated solvent rich stream has a solids content ranging from about 10% by weight to about 45% by weight.
22. The process according to claim 16 wherein said concentrated solvent rich stream has a solids content ranging from about 10% by weight to about 30% by weight.