Focus application : PTA (terephtalic acid)

Uses of PTA

PTA, (or purified terephtalic acid – chemical formula C8H6O4), derived from crude oil by chemical synthesis, is one of the main components of polyesters.

formula-pta

It is used for :
– The manufacture of polyester fibers based on PTA either alone or in blends with natural or synthetic fibers.
(65% of PTA world production)
– The manufacture of PET bottle resins (27% of PTA world production)
– The manufacture of polyester films based on PTA, used for audio and video recording tapes, data storage tapes, photographic films, labels etc. ; pharmaceutical industry : raw material for drugs ; raw material for polyesters’ production used for fabrication of powder and water-soluble coatings. (8% of PTA world production).

pta-fiber-polyester_webpta-drugs-webpta-photo-web

Manufacturing process of PTA

Modern technologies produce purified terephthalic acid by the catalytic liquid phase oxidation of paraxylene in acetic acid, in the presence of air. The process uses manganese or cobalt acetate as a catalyst. The reaction is exothermic, producing water which is removed in a solvent recovery system. Acetic acid produced by the previous reaction is returned to the reactor together with the oxidation catalyst. The resulting PTA is purified in a crystalliser where the unreacted xylene and water are flashed off.

Recommended valves

Guichon proposes a wide range of products adapted to corrosion and PTA’s other constraints:

tank bottom valve for pta guichon
tank bottom valve for pta guichon valves

– Welded or cast construction
– Materials : Austenitic stainless steels 304L, 316L, 316Ti, 321, Uranus® B6 or equivalent, duplex steels, nickel and nickel alloys (alloy 20, Hastelloy®, Inconel®, Incoloy®, Monel®), special alloys (Titanium, Zirconium, Tantalum)
– Closure system (disc or piston)
– DN from 1/4” to 40”
– PN10 to 100 (ANSI 150 up to 600)
– Maximum temperature : 300°C
– Pneumatic equipment suitable for corrosive atmosphere
– With or without heating jacket