Ethylene Epoxidation in a Low-Temperature Parallel Plate Dielectric Barrier Discharge System: Effect of Oxygen Source

The objective of this work was to investigate the effects of two different oxidizing agents [nitrous oxide (N2O) and air], compared to the reported pure oxygen (O2), on the ethylene epoxidation performance in a low-temperature parallel plate dielectric barrier discharge (DBD) system with two frosted glass plates as the dielectric barrier material under ambient temperature and atmospheric pressure. A separate feed technique, with the ethylene (C2H4) feed position fraction of 0.5, was used to reduce all the undesirable reactions and to maximize the ethylene oxide (EO) production (selectivity and yield). The N2O system with a N2O/C2H4 feed molar ratio of 0.17:1 exhibited the highest ethylene epoxidation performance (80.1% EO selectivity and 21.9% EO yield) with a very low carbon monoxide selectivity and the lowest power consumption, as compared to pure O2 and air as oxidant systems at their respective optimal feed molar ratios of 0.2:1 and 0.1:1, respectively. Interestingly, the EO yield from the DBD system with N2O was about 2-fold higher than that of the O2 and air system.