Process And System For Purification Of Aromatic Dicarboxylic Acid

摘要

In a process/system for the purification of aromatic dicarboxylic acid (ACA), crude ACA solids are slurried with water recycled from at least a filtration step in a feed preparation zone. Flash steam in vapour phase is supplied to the zone from at least one of a crystallisation step, a filtration step, and a drier step. The slurried ACA solids are preheated to form a solution that is then hydrogenated. The ACA is allowed to crystallise and then crystals of pure ACA are filtered out and water is recovered in a single stage filtration process. Recovered water is supplied to the feed preparation zone and the crystals are dried and recovered. The flash steam recovered from the crystallisation step, filtration step and/or drier step is recovered as a vapour phase stream having a pressure from about atmospheric to 5 barg and supplied to the feed preparation zone without phase change.

主权项

1. 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) allowing 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 steam 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.