A carbon neutral and circular economy must rely on utilization of waste materials and biomass as feedstock for the production of new materials. Its energy input must be of zero carbon footprint, which essentially is intermittent electricity. Some of the challenges encountered in the transition towards such an economy can potentially be addressed by plasma technology. Particularly its compatibility with (intermittent) sustainable energy and unique opportunities for efficiency and/or selectivity in reactions with CO2, N2, and CH4 inspire our research in the context of the process industry at Chemelot. This presentation discusses various use cases of CH4 valorisation via carbon coupling to illustrate the plasma opportunity. The insights are used to draft a roadmap for industrial implementation of the technology for direct production of acetylene and/or ethylene as important building-block for the chemical industry.
The non-oxidative coupling of methane in a microwave plasma discharge configuration will be presented as a highlight. Spontaneous laser Raman scattering spectroscopy is applied in situ and yields reactor temperatures between 2100 K and 3000 K in dependence of power, pressure, and H2 admixture. Comparison of the in situ data with measurements of product yield and 1D reaction kinetics modelling illustrates how mass and heat transfer can be controlled to maximize performance. In this particular example, we achieved an energy requirement of 9.4 kWh/kg-C2H2 and 50% C2H2 yield.