Ethylene epoxidation in a low-temperature corona discharge system : effect of distance between plate electrode and ethylene feed position

Abstract

Ethylene oxide (C2H4O, EO) is an important industrial chemical. Its major use is in the production of ethylene glycol. It can also be used to produce detergents by a process called ethoxylation, sterilants for foodstuffs, sterilants for medical equipment and supplies, solvents, antifreezes, adhesives, and cosmetics. Therefore, the ethylene epoxidation is a very important process for ethylene oxide production. In this work, the epoxidation of ethylene in a low-temperature corona discharge system was studied to improve the ethylene epoxidation performance using the corona discharge system by initially producing an O2 plasma prior to reacting it with ethylene, which was fed into the system at various positions of the plasma zone. Various operating parameters, including distance between plate electrode and C2H4 feed position, O2/C2H4 feed molar ratio, applied voltage, input frequency, total feed flow rate, and gap distance between pin and plate electrodes, were optimized. It was found that the highest EO yield of 1.76% was achieved under the operating conditions of a distance between plate electrode and C2H4 feed position of 0.2 cm, an O2/C2H4 feed molar ratio of 1:2, an applied voltage of 18 kv, an input frequency of 500 Hz, a total feed flow rate of 100 cm3/min, and an electrode gap distance of 10 mm. Under these optimum conditions, the power consumption was found to be as low as 6.07xlO-16 Ws/molecule of EO produced.