Title of Invention

A PROCESS FOR PURIFICATION OF TEREPHTHALIC ACID

Abstract

The present invention relates to a process for the preparation of purified terephthalic acid which comprises introducing a liquid slurry containing crystallized terephtalic acid with impurities into a high pressure rotary filter and collecting at least some of the solid portion. The filter typically consists of a case, pressurized at process pressure, and a dr4um covered by a filtering device such as, for example, a cloth or equivalent filtering device, pressurized at a pressure suitable lower than the case. The drumis ideally divided into three zones; first zone, where the excess of washing liquor is removed and the solid is discharged. The solid portion is washed, onto the filter drum, with additional amounts of water. The washed solid portion is then transferred to a letdown zone, which is at a pressure less than the zsone in which the solid portion was collected. After the solid portion is transferred into the letdown zone,the connection between the letdown zone and the collection zone is sealed, suth that a change of pressure in the letdown zone will not affect the pressure in the collection zone. The pressure of the letdown zone is then gradually reduced and the solid removed. The letdown zone is then pressurized back up so that it is ready to accept additional solid from the rotary filter.

Full Text

Documents:

in-pct-2002-1000-che abstract.pdf

in-pct-2002-1000-che claims.pdf

in-pct-2002-1000-che correspondence others.pdf

in-pct-2002-1000-che description (complete).pdf

in-pct-2002-1000-che form 1.pdf

in-pct-2002-1000-che form 13.pdf

in-pct-2002-1000-che form 19.pdf

in-pct-2002-1000-che form 3.pdf

in-pct-2002-1000-che form 5.pdf

in-pct-2002-1000-che form 6.pdf

in-pct-2002-1000-che power of attorney.pdf