High-temperature flash methane conversion to acetylene and ethylene via a simple induction reactor

Low-carbon feedstocks and electrified processes are key directions for chemical technology. A long-standing and highly anticipated approach is the direct conversion of methane (CH 4 ) to C 2 -hydrocarbons (C 2 -HC), which still faces challenges in commercialization due to complex reactors and low CH 4 utilization efficiency. We developed a simpler and more efficient method using electromagnetically heated graphite tubes as Joule heat sources. It rapidly accommodates flash endothermic reactions, achieving the highest CH 4 efficiency and C 2 -HC yields reported to date. The present work, for the first time, investigates the reactions and kinetics under a broader range of operating conditions, and examines the magnetic and electric fields and temperature distribution in the reactor via COMSOL simulations. Results show that, at a fixed magnetic frequency and graphite tube outer diameter, the adiabatic heating rate and maximum steady-state temperature of the graphite tube are primarily determined by the input power-to-mass ratio and input power, respectively. Under optimal conditions (2 mm tube inner diameter, 1860 °C, 2.1 ms residence time, and CH 4 hourly space velocity of 2.4 × 10 5 h −1 ), CH 4 conversion reaches 94.1 %, with 71.6 % and 18.6 % carbon yields for C 2 H 2 and C 2 H 4 , and 67.6 % hydrogen yield for H 2 . Furthermore, H 2 addition effectively suppresses carbon black (C) formation. The reactions are well-described by a sequential first-order pathway (CH 4 → C 2 H 4 → C 2 H 2 → C), where the rate constants depend on the graphite tube’s inner diameter.