Improving performance of induction-heated steam methane reforming

Induction heating may be an electrical solution for heating of catalytic reactors. Recent studies have shown that CoNi nanoparticles may act as both inductors for hysteresis heating and catalyst, such that they in an alternating magnetic field are able to drive the strongly endothermic steam methane reforming reaction with > 90% gas conversion at temperatures of ≈800 °C.

However, lab-scale induction-heated reactors are limited by low energy transfer efficiency and previous work did not optimize the surrounding instrumentation. Here, we focused on the optimization of an induction setup for steam methane reforming. The performance of the reactor system was investigated through experiments at varying alternating magnetic field conditions, to evaluate the effect of frequency and coil geometry.

The results from these experiments were modelled by a simple theoretical framework. Increasing the frequency of the alternating magnetic field from 68 kHz to 189 kHz was found to increase the energy transfer efficiency. Moreover, the energy transfer efficiency also increased when going from a short and wide coil with height to radius ratio of 3.8 to a long and narrow coil with height to radius ratio of 10.8.

Overall, the energy transfer efficiency was increased from an initial 11% in the bench scale reactor setup, to 23% in the optimized version. Moreover, combining the bench scale results with the theoretical framework we extrapolated the data to large-scale systems. The analysis indicated that the energy efficiency of induction-heated steam reforming systems scaled to larger H2 capacities may be above 80%.

This efficiency would allow the technology to be competitive with other electricity driven routes to hydrogen production when considering only the energy requirements.