摘要:
Processes for separating a solid from a solids-liquids slurry under conditions that prevent ingress of molecular oxygen are advantageous where the presence of molecular oxygen would otherwise reduce efficiencies, contribute to limited product yields, and potentially compromise safe operation of the process or downstream unit operations. Among the various embodiments disclosed herein, is a process utilizing filter columns as solid-liquid separators in combination with crystallization and reslurry unit operations to recover a product component from an initial feed mixture of miscible components. Embodiments of the disclosed processes may include the separation and purification of a product component using a crystallizer in series with a filter column followed by a chemical reactor, using a reslurry drum in series with a filter column, and using a combination of crystallizers and/or reslurry drums in series with at least one filter column. The use of filter columns in such processes is particularly attractive because these columns, when operated under the conditions disclosed herein, limit the undesirable ingress of molecular oxygen into the various process streams, and further improve process efficiencies related to both product component recovery and operating costs.
摘要:
A process for oxidizing a dialkyl substituted benzene, such as meta-xylene, to an aromatic polycarboxylic acid, such as isophthalic acid, in the presence of a solvent, such as acetic acid, in an oxidation zone followed by an oxidation-crystallization zone, wherein a secondary dehydration tower is used to separate water from the solvent in the overhead stream from the oxidation-crystallization zone and provide a solvent-rich fluid for recycle to the oxidation zone, resulting in expanded capacity of the process coupled with a minimization of captial cost.
摘要:
The invention is an improved method of purification of isophthalic acid comprising recycling a portion of the mother liquor solution into the feed solution of an isophthalic acid purification process. The improved method comprises the following steps:(a) dissolving crude isophthalic acid in a feed solution comprising a polar solvent at a temperature of from about 100.degree. C. to about 300.degree. C.;(b) crystallizing the isophthalic acid by cooling the solution of step (a) to a temperature of from about 35.degree. C. to about 120.degree. C.;(c) separating the isophthalic acid crystals from the solution and drying the crystals; and(d) recycling a portion of the solution remaining after the separation of isophthalic acid crystals back to the feed solution.
摘要:
Processes for separating a solid from a solids-liquids slurry under conditions that prevent ingress of molecular oxygen are advantageous where the presence of molecular oxygen would otherwise reduce efficiencies, contribute to limited product yields, and potentially compromise safe operation of the process or downstream unit operations. Among the various embodiments disclosed herein, is a process utilizing filter columns as solid-liquid separators in combination with crystallization and reslurry unit operations to recover a product component from an initial feed mixture of miscible components. Embodiments of the disclosed processes may include the separation and purification of a product component using a crystallizer in series with a filter column followed by a chemical reactor, using a reslurry drum in series with a filter column, and using a combination of crystallizers and/or reslurry drums in series with at least one filter column. The use of filter columns in such processes is particularly attractive because these columns, when operated under the conditions disclosed herein, limit the undesirable ingress of molecular oxygen into the various process streams, and further improve process efficiencies related to both product component recovery and operating costs.