Electrified methane reforming: Elucidating transient phenomena

Increasing implementation of renewable energy requires an infrastructure compatible with the intermittent production of green electricity. Herein we show the flexibility of electrically heated steam methane reforming with integrated ohmic heating, through a combination of CFD modelling and lab scale reactor tests. It is shown how start-up from an idle state to operation conditions can be achieved with instantaneous application of the full power required for a steady state conversion of 80%, with initial heating rates exceeding 50 degrees C/min. The initial heating rate is correlated to the thermal mass of the reactor, with the endothermic reaction governing the temperature profile. Cyclical operation displays no apparent delay between the change in temperature and methane conversion. The highest thermal gradient across the washcoat is predicted at steady state, with no increase during start-up despite the higher heating rates. The highest risk of carbon formation is predicted at the inlet at steady state operation. A temporarily peak in the equilibrated carbon potential is predicted near the outlet during start-up and shutdown between 500 and 600 degrees C, governed by the thermodynamics of the feed composition. Integrated ohmic heating supports steam methane reforming scalable to industrial conditions, operating closer to thermodynamic limits for carbon formation, and potentially based on the access to intermittent excess of renewable energy.

Automated summary

The study demonstrates the rapid start-up from an idle state to operation conditions using electrically heated steam methane reforming technology, with no apparent delay between temperature change and methane conversion in cyclic operation. The highest thermal gradient is predicted in the washcoat at steady state operation, without an increase during start-up.