A SIMULATION STUDY ON CONTINUOUS DIRECT ESTERIFICATION PROCESS FOR POLY(ETHYLENE-TEREPHTHALATE) SYNTHESIS

A mathematical model for a continuous direct esterification reactor ha s been developed. The solid-liquid equilibrium of terephthalic acid (T PA) was considered in our modeling, and the characteristic dissolution time, an adjustable parameter, was introduced to account for the mass -transfer effect in the dissolution of TPA. The effects of the charact eristic dissolution time, monomer feed ratio, temperature, and pressur e on the reactor performance at different residence times were investi gated through simulation. It was observed that the behavior of the fir st reactor strongly depends on whether the solid TPA is completely dis solved in the reaction mixtures. From the dynamic simulations, it was found that a sudden change in the operating conditions affects the eth ylene glycol (EG) vapor flow rate instantly. For the esterification pr ocess having two reactors in series, the strategy for time distributio n and recycling of EG is also discussed. (C) 1997 John Wiley & Sons, I nc.