Microwave plasma-based method of hydrogen production via combined steam reforming of methane

•Microwave (2.45 GHz) plasma was used for hydrogen production via methane conversion.•Experiments concerning combined steam reforming of methane were performed.•The hydrogen production was carried out with methane flow rate up to 9000 NL/h.•Experiments show that presented method have high potential for hydrogen production.•The new plasma hybrid system for H2 production was also presented.

This paper presents a contribution to the development of microwave plasma-based technology for hydrogen production. The efficiency of hydrogen production via combined steam reforming (i.e. with the addition of CO2 and water vapour) of methane in a waveguide-supplied metal cylinder-based microwave plasma source (MPS) was for the first time tested experimentally. The operating parameters were: microwave frequency of 2.45 GHz, maximum absorbed microwave power of 6 kW, and working gas (methane + CO2 + water vapour) flow rates up to 9000 NL/h. The tested parameters of hydrogen production efficiency were: the hydrogen production rate, energy yield, methane conversion degree, and hydrogen volume concentration in the outlet gas. It was proven that using the microwave system, the plasma steam reforming of methane can be run stably at high gas flow rates (several thousand NL/h). By optimizing the process input parameters, i.e. the absorbed microwave power, working gas composition and flow rate, an energy yield of hydrogen production of 42.9 g(H2)/kWh could be achieved. The test showed that the microwave plasma method presented in this paper can also be used efficiently for reforming other gaseous and liquid compounds. In this paper, a new plasma hybrid system for H2 production is also presented.