Production of Ethylene glycol from ethylene

The production of ethylene glycol (MEG) has been primarily used as a main material in the manufacturing of polyester fibers, fabric industry, and polyethylene terephthalate resins used in making PET bottles. The demand for global production of MEG continuously increases to about 12.1% in 2010 and forecasted to grow 5.4% through the year 2015. Due to the large percentage of increase from the 19.5 million metric tons production, the development of new EG plant is promising. A plant production of 177,508.47 metric tons per annum would constitute to a small percentage of the global increase of demands. Thus, the aim of this project is to design and determine the feasibility of MEG plant with annual capacity of 177508.47 tons of 90.5 mol% purity or 84.50 wt% purity products. The product is to be in liquid form. Diethylene glycol and Triethylene glycol impurities is present in the product due to the side reaction of the two-step chemical process.
Ethylene is first reacted with 99.5% oxygen to produce ethylene oxide. High concentration of oxygen is used to reduce the amount of inert in the system. This makes the selectivity of ethylene oxide to 80%. The ethylene oxide product is further reacted with water to form the desired product Ethylene glycol. Water added to the ethylene oxide reactor is 10 times the molar amount of the needed to increase the selectivity of the production of ethylene glycol.
The feed materials are 89,718.3936 metric tons per annum of ethylene from a Naphtha cracking plant and 71,752.0842 metric tons per annum which will be supplied by an oxygen generation plant. The amount of water to be supplied to the reactor is 529317.4122 metric tons per annum, however only 38,273.3683 metric tons per annum reacts while the excess is regenerated and recycled.
The economic margin is computed to be 75.76%. The capital investment of this plant is estimated to be 691.7098 Million pesos with the rate of return of the plant is 74.94%. The preliminary computations of the plant economics suggest that this plant design is feasible. The break even period is estimated to be 3.01 years. At this stage, our recommendation is to proceed with this project to the next stage of development.

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