Relating catalytic activity of CrHZSM-5 in oxidative dehydrogenation of liquefied petroleum gas under an external DC electric field to electrical properties

The CO 2 oxidative dehydrogenation (ODH) of liquefied petroleum gas (LPG) was studied on CrHZSM-5 in a fixed bed reactor and in the presence of an electric field. A central composite design (CCD) was used to study the effect of reaction temperature, electrical current, gap distance, and Cr metal loading in HZSM-5 on LPG conversion and olefins selectivity. The levels of the independent variables were: temperature (550 °C–700 °C), electrical current (0–12 mA), gap distance (6–14 mm), and chromium loading (0.5–7.5 wt%). The resulting correlation was used to predict optimum reaction conditions, verified experimentally, that maximize the production of light olefins from LPG under an electric field. Overall, the conversion of LPG was greatly increased by low intensity and effective application of the electric field (18–77 volt) to the catalyst bed. The obtained results indicated that the maximum olefins yield value (46.9%) can be achieved at 673.7 °C, input electrical current of 11 mA, gap distance of 6.55 mm and Cr metal loading of 4 wt%. The reasons for the catalytic activity enhancement in the presence of an electric field are also discussed.