Abstract:
Ethylene Dichloride, or EDC for short, is one of the most crucial components at Engro Polymers. Other than its primary usage, as an intermediate, in the manufacturing process of Vinyl Chloride Monomer, it has an immense market for sale. Owing to the value that potentially be generated with a good quality EDC stream, this project focuses on increasing the purity of the Recycle EDC stream, by removing Benzene and other impurities - Trichloro Ethylene, Chloroprene etc.
A statistical determination for the most optimum operating procedure for the removal of said impurities is detailed in the project. The purification of the EDC stream would eventually maximize final product yield, reduce waste treatment costs, lower raw material costs, reduce fouling in the furnace owing to impurities and increase cracking rates in the furnace.
The proposed solution revolves around the usage of a series of distillation columns, a few heat exchangers and chlorinator reactor. After the removal of light fractions and water in the Heads & Lights column from the EDC process stream coming from the crude EDC tank and the furnace recycle. the Benzene, which otherwise forms a close boiling point azeotrope with EDC, is converted to a higher boiling fraction of Monochlorobenzene. This conversion, which forms the heart of the proposed solution, takes place inside a packed bed chlorinator reactor at 65 °C and 200 kPa, making use of γ-Alumina catalyst. The Hiboil column, now separates the heavies in the stream to produce a 99.5% pure EDC stream which is sent to furnace for further usage. The vacuum column further serves to concentrate the residual EDC in the stream.
Overall, the process thus presents a sustainable, environment friendly and energy efficient pathway for the purification of EDC. The process is presented with elaborate detail along with process flow diagrams, material and energy balances, equipment design, simulation, costing and HAZOP analysis.
