Study On Rectifying Process Of Ethylene Glycol Synthesized By Homogeneous Catalytic Hydration

Synthesis of ethylene glycol by catalytic hydration (EG) significantly brings downthe proportion of H2O and ethylene oxide (EO), that is to say, the proposedtechnology saving the energy is superior to that of the present industrial directhydration. Therefore, the technology of catalytic hydration is becoming one of thefocal points in the study of EG synthesis.According to the proposed technology of homogenous catalytic hydration, thispaper did systematic experiments in the distillation process containing catalysts. Moredetailed, the paper analyzed how the homogeneous catalyst and the rectificationcontaining catalyst affected the quality of EG product and got the optimal operatingcondition of distillation. The dynamic viscosity of EG solution containing catalystwas measured in different temperature to supply the industrial data of catalysttransportation. In the paper, the isotonic VLE data of H2O-EG containing catalystwere also measured, one suitable thermodynamics model was selected, and interactionparameters of H2O-EG were fitted. In the end of the paper, the calculation and designof distillation was accomplished by utilizing PRO/II.Some problems were settled in the study, such as the quality control of EG in thedistillation process, recycling utilization of catalyst and calculation of distillation,which established the basis of the achievement of commercial process. The study ofthis paper mainly included the following aspects:(1) The experimental research of influence factors on the ultraviolet transmittance(UV) of EG product showed that the catalyst can absorb ultraviolet andaccelerated ethylene glycol oxidation with air and under high temperaturecondition, so the EG product should be conserved without air. The UV of EGcan reach the standard of Science Design (S.D) Company when thetemperature of rectifying was under 153℃, which was lower than thetemperature of distillation without catalyst. IABSTRACT(2) The temperature of recycling liquid should be 120~140 ℃ when itsconcentration was 50~55%, which was favorable for its transporting function.(3) The catalyst had some influence on vapor-liquid equilibrium of H2O-EG, so itseffect was added to UNIFAC interaction parameters which were calculated asaij'= -115,aji'= -255. The calculated number of theoretically perfect trays hadone more tray than that of no catalyst system, which coincided well withactual distillation.