EFFECT OF REACTION VARIABLES ON TPA-EG CONTINUOUS ESTERIFICATION WITHRECYCLING IN PET PRODUCTION PROCESS

Simulations of a continuous recycle process were carried out for the d irect esterification between terephthalic acid and ethylene glycol in the production of poly(ethylene terephthalate). The influence of react ion pressure, recycle ratio and residence time on the oligomer charact eristics was examined and the following results were obtained: (1) The main reactions go on further under higher reaction pressure but the s ide reactions on diethylene glycol (DEG) proceed to a greater extent t han the main reactions. (2) The higher residence time ratio of the fir st reactor to the total promotes esterification remarkably as the pres sure becomes high. (3) As the recycle ratio becomes high, the polymeri zation degree becomes high, but, at higher degrees of polymerization, the tendency is reversed. (4) The oligomer characteristics are almost the same at the same esterification degree independently of the reacti on conditions.