Routing of purified aromatic carboxylic acid filter rinse for energy optimization
A process for manufacturing a purified aromatic carboxylic acid is provided. The process comprises purifying a crude aromatic carboxylic acid in a purification zone to form a purified aromatic carboxylic acid; crystallizing a purified aromatic carboxylic acid in a crystallization zone to form a solid/liquid mixture comprising purified aromatic carboxylic acid solids; filtering the solid/liquid mixture through a filter member of a rotary pressure filter apparatus to form a filter cake comprising the purified aromatic carboxylic acid solids; removing the filter cake from the filter member; rinsing the filter member to produce a filter rinse product, wherein the filter rinse product comprises purified aromatic carboxylic acid; and directing at least a portion of the filter rinse product downstream of the purification zone for recycle to the rotary pressure filter apparatus.
1. A process for manufacturing a purified aromatic carboxylic acid comprising:
purifying a crude aromatic carboxylic acid in a purification zone to form a purified aromatic carboxylic acid;
crystallizing a purified aromatic carboxylic acid in a crystallization zone to form a solid/liquid mixture comprising purified aromatic carboxylic acid solids, wherein the crystallization zone comprises a plurality of crystallizers in series;
filtering the solid/liquid mixture through a filter member of a rotary pressure filter apparatus to form a filter cake comprising the purified aromatic carboxylic acid solids;
removing the filter cake from the filter member;
rinsing the filter member to produce a filter rinse product, wherein the filter rinse product comprises purified aromatic carboxylic acid; and
directing at least a portion of the filter rinse product downstream of the purification zone for recycle to the rotary pressure filter apparatus, said recycle being via a recycling line and a pump that increases the pressure of the filter rinse product in the recycling line.
2. The process of claim 1 , further comprising recovering the purified aromatic carboxylic acid solids from the filter cake.
3. The process of claim 1 , wherein directing at least a portion of the filter rinse product downstream of the purification zone comprises directing at least a portion of the filter rinse product to the crystallization zone.
4. The process of claim 1 , wherein the filter rinse product is not substantially redissolved prior to recycle to the rotary pressure filter apparatus.
5. The process of claim 4 , wherein less than 5 percent of the filter rinse product is redissolved.
6. The process of claim 1 , further comprising heating the filter rinse product in order to dissolve fines in the filter rinse product.
7. The process of claim 1 , wherein directing at least a portion of the filter rinse product downstream of the purification zone comprises directing at least a portion of the filter rinse product to a drum and pumping with the pump the filter rinse product from the drum.
8. The process of claim 1 , further comprising oxidizing a substituted aromatic compound in an oxidation reactor to form the crude aromatic carboxylic acid.
9. The process of claim 1 , wherein the purifying a crude aromatic carboxylic acid in a purification zone comprises contacting a crude aromatic carboxylic acid with hydrogen in the presence of a catalyst in a hydrogenation reactor to form at least a portion of the purified aromatic carboxylic acid fed to the crystallization zone.
10. The process of claim 1 , further comprising drying the filter cake to form a purified carboxylic acid product.
11. The process of claim 1 , wherein the filter rinse product is directed to a last crystallizer in the sequence.
12. The process of claim 1 , wherein the aromatic carboxylic acid comprises terephthalic acid.
13. The process of claim 1 , wherein the filter member is a filter cloth.
14. The process of claim 13 , wherein the filter cloth comprises polyether ether ketone polymer.