Direct resistive heating of a catalytic fixed-bed reactor for ethanol dehydration

Abstract

Direct resistive heating is an effective and sustainable method for supplying heat to endothermic reactions. Ethanol dehydration, a sustainable route for producing ethylene, was chosen as the test reaction. A physical mixture of graphitic carbon particles serving as conductors and γ-Al₂O₃ as catalyst particles was prepared to create an electrically conductive fixed bed. A minimum of 33.4 vol% of conductive material ensured sufficient bed resistivity. Successful direct resistive heating was demonstrated, with near complete ethanol-to-ethylene conversion achieved at a bed temperature of 325 °C and a WHSV_EtOH of 3.2 h⁻¹. In contrast to the industrial process, which requires superheating to 470 °C with steam as the heat carrier gas, direct resistive heating operated at a lower temperature with 10 times higher productivity, without the need for a heat carrier gas. Upscaling in a 500 ml ceramic tubular reactor confirmed scalability, showcasing a sustainable method for ethylene production using green energy and renewable bio-ethanol.