the application of statistical techniques to reduce ethylene glycol in waste water produced by esterification reaction in polyester manufacturing process

This study aimed to find the factors that influence the amount of ethylene glycol (EG) in waste water, produced by the esterification reaction in polyester manufacturing process, and to set these influential factorsat the proper level, which leads to small amount of EG and low waste water treatment cost but same polyester quality. Several experiments were designed and performed to achieve the research objectives. The studybegan with reviewing various relevant documents and interviewing specialists to define the potential factors. Consequently, there were 4 potential factors: the reaction temperature, the level of slurry in reactor, the EGfeeding rate, and the water temperature in distillation column. To find the influential factors, One-Factor- At-a-Time (OFAT) experiments were applied to define the significant factors. Then, a factorial designexperiment was implemented to analyze their interaction effects. The experiments revealed that the reaction temperature, the level of slurry in reactor, and the EG feeding rate best setting condition, the results showed that EG volume was decreased on average 10.15% and that waste water treatment cost was reduced 27.82%.