Process for Energy Recovery in Purifying Carboxylic Anhydride for Manufacturing Cellulose Esters

摘要

Integration of a carboxylic anhydride purification system in the manufacturing of cellulose esters may include processes that includes distilling the crude carboxylic anhydride stream (that includes a carboxylic anhydride and a carboxylic acid) in a distillation column having an overhead or side stream comprising purified, vaporous carboxylic anhydride and a bottoms stream; heating a steam condensate stream in a steam generator to yield a low-temperature steam; and cooling at least a portion of the overhead or side stream to yield a cooled overhead or side stream. In some instances, a heat exchanger may be utilized in parallel or series with the steam generator.

主权项

1. A process for the recovery of the heat from a carboxylic anhydride distillation column, comprising the steps of:
providing a crude carboxylic anhydride stream comprising a carboxylic anhydride and a carboxylic acid; distilling the crude carboxylic anhydride stream in a distillation column having an overhead or side stream comprising purified, vaporous carboxylic anhydride and a bottoms stream; providing a steam generator comprising a first process inlet, a first process outlet, a first water inlet, and a first steam outlet; introducing at least a portion of the overhead or side stream to the steam generator via the first process inlet; introducing a steam condensate stream to the steam generator via the first water inlet; heating the steam condensate stream in the steam generator to yield a low-temperature steam; cooling the portion of the overhead or side stream to yield a cooled overhead or side stream; wherein the low-temperature steam exits the steam generator via the first steam outlet and the cooled overhead or side stream exits the steam generator via first process outlet; and wherein the temperature of the first process outlet is lower than the temperature of the first process inlet.