Process Design For Seperation Of Ethylene-Oxide & Water

Abstract

Ethylene Oxide was first reported in 1859 as being prepared from the reaction of potassium hydroxide on ethylene chlorohydrin. But nowadays it is mainly prepared by direct oxidation of ethylene with oxygen on silver based catalyst. In its final product stream along with ethylene oxide many other impurities like formaldehye, acetaldehyde, unconverted ethylene, water and other inert gases are also present. So its purification consist of many stages which includes stripping zone, scrubbing zone, phase seperator, an ethylene oxide purification zone and their interconnections. In its scrubbing step ethylene oxide is scrubbed from other impurities with help of excess of water which needs to be removed so it can be reused for scrubbing purpose as well as to get pure ethylene oxide. For commercial purpose like its use in epoxy paints, as surfactants demands highly pure ethylene oxide having purity of more than 99.5%. Present study aims to seperate Ethylene oxide from water at minimum cost and high purity using distillation process as a means of purifying technique and then designing its heat excahngers . So here two case studies were taken where in 1st case study feed composition of Ethylene oxide taken to be at its maximum solubility limit of 0.5 mass fractiona at 1 atm pressure, while in another case study real manufacturing data of ehtylene oxide production facility was taken to design separation process which is feasible economically as fulfilling the required purpose. For designing of the process initially design basis was fixed . Literature survey was carried out to decide the type of operation to be used to separate ethylene oxide from water and to obtain purity of 99% ethylene oxide in distillate. Then from literature many different VLE data were collected at different operating Condition inorder to decide the type of fluid package to be used in the simulator used to simulate the selected unit operation. Once fluid package was decided next was to simulate the operation and the to optimize considering in mind economic cost as required product purity. Finally Heat exchangers were designed for the the cases for which literature review was carrried out for selection of type of exchanger and then designing was carried out using manual calculation as well HTRI software.