Ethylene Epoxidation in Low-Temperature AC Dielectric Barrier Discharge: Effect of Electrode Geometry

Abstract

In this work, the epoxidation of ethylene under a cylindrical dielectric barrier discharge (DBD) reactor and a parallel DBD reactor was comparatively studied. The effects of important operating parameters-feed O 2 /C 2 H 4 molar ratio, applied voltage, input frequency, and residence time-were investigated on the reaction performance in terms of reactant conversions, product selectivities, product yields, and power consumptions per molecule of ethylene converted and per molecule of ethylene oxide produced. The optimum conditions obtained from the operating parameter investigation were used for a comparative performance evaluation of both DBD reactor systems. It was found that under the optimum conditions of each system, the cylindrical DBD system exhibited superior epoxidation performance for ethylene oxide production compared to the parallel DBD system, indicating that the electrode geometry (electrode edge length-to-electrode surface area ratio) plays a significant role in the ethylene epoxidation.

Ethylene Epoxidation over Alumina- and Silica-Supported Silver Catalysts in Low-Temperature AC Dielectric Barrier Discharge

“…The studied DBD plasma system was operated under the base conditions described in our previous work [26], which were an O 2 /C 2 H 4 feed molar ratio of 1/4, a total feed flow rate of 50 cm 3 /min, an electrode gap distance of 0.7 cm, an input frequency of 500 Hz, and an applied voltage of 19 kV. The effects of Ag loading and support on the ethylene epoxidation reaction were investigated in this work.…”

Ethylene epoxidation in a low-temperature parallel plate dielectric barrier discharge system with two frosted glass plates

“…The configuration of electrodes was found to influence the efficiency of EO production in that a cylindrical DBD provided superior ethylene epoxidation performance as compared to a parallel plate DBD [7]. The input power, voltage, and electrode gap distance significantly affected the performance of methane reforming [11,12,[30][31][32], corresponding to the study that the dielectric material and thickness changed the plasma behavior [33].…”

“…Therefore, a search for a new method with lower energy consumption, a lower reaction temperature and without the use of a catalyst is of great interest. Non-thermal plasma has been reported to be an alternative technique for several reactions including ethylene epoxidation [7,8], natural gas reforming (H 2 production) [9][10][11][12][13], chemical vapor deposition [14][15][16][17][18][19][20][21], and desulfurization [22,23].…”

“…Our research group has investigated ethylene epoxidation reaction in several types of low-temperature plasma reactors: a corona discharge [4,34,35], a parallel DBD [8], a cylindrical DBD [7,36], a DBD jet [37], a parallel DBD with supported Ag catalysts [38] and a single clear glass plate [39]. In this work, a lowtemperature parallel plate dielectric barrier (DBD) with two frosted glass plates was investigated for ethylene epoxidation reaction.…”

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

“…Dielectric barrier discharge (DBD) is a type of nonequilibrium low temperature plasma that has high electron temperatures (10 4 –10 5 K) with a bulk gas temperature close to room temperature. , As a consequence, the energy consumption used for operating the plasma system for various chemical reactions is lower compared to conventional catalytic processes. Accordingly, DBD has been employed for several studies, including chemical synthesis, such as hydrogen (H 2 ) production by methane (CH 4 ) reforming − and ethylene epoxidation, − ozone generation, − soil remediation, − wastewater treatment, , and surface treatment. − …”