Comparing catalyst powders and pellets for microwave assisted biogas reforming

• Dry reforming was tested over Ni/SiC powders and pellets. • Experiments were conducted in microwave heated reactor. • Radial temperatures were measured during microwave heating. • Catalyst coking occurred during dry reforming probably due to cold spots. Reactor electrification is a promising technology to reduce carbon dioxide emissions in the chemical industry. Moreover, it allows for more compact reactor design and leads to process intensification. Microwave technology can be used to effectively heat solid catalysts for endothermic reactions with numerous benefits. However, microwave heating is restricted to certain materials only and in most cases new catalyst development is necessary. Whereas many studies focus on microwave assisted catalysis over powder samples, studies on industrial pellets or extrudates are far less common. This study compares microwave-assisted biogas reforming over 5 wt.% Ni/SiC in powder and pellet form (2 mm × 2 mm), tested at different temperatures (750, 800, and 850 °C) and gas flow rates (100, 200, 300, and 400 mL/min). Both forms of the catalyst show good activity, but limited long-term stability. Radial temperature gradients caused by radiation losses through the quartz reactor wall, were measured directly by using a fiber optic temperature sensor located inside the bed center and an IR camera at the reactor wall.