PROCESS FOR THE PURIFICATION OF AROMATIC DICARBOXYLIC ACID.

摘要

A process for the purification of aromatic dicarboxylic acid comprising the steps of: (a) slurrying crude aromatic dicarboxylic acid solids with water recycled from at least a filtration step in a feed preparation zone; (b) supplying flash steam in vapour phase to the feed preparation zone from at least one of a crystallisation step, a filtration step, and a drier step; (c) preheating the slurried aromatic dicarboxylic acid solids to form a solution; (d) subjecting the heated solution to hydrogenation; (e) pure aromatic dicarboxylic acid to crystallise; (f) filtering out the crystals of pure aromatic dicarboxylic acid and recovering water in a single stage filtration process; (g) supplying at least part of the recovered water to the feed preparation zone; and (h) drying the filtered crystals and recovering same, wherein the flash stream recovered from at least one of a crystallisation step, a filtration step or a drier step is recovered as a vapour phase stream having a pressure of from about atmospheric to 5 barg and is supplied to the feed preparation zone without phase change. Also described is a system for the purification of aromatic dicarboxylic acid and a feed preparation vessel therefor.