Techno-economic and life-cycle assessment for syngas production using sustainable plasma-assisted methane reforming technologies

Abstract

This study combines for the first time techno-economic and life-cycle assessment metrics to evaluate the economic and environmental viability of plasma-assisted dry reforming of methane (DRM) for producing syngas from methane-rich natural gas. The study compares three different processes (plasma-assisted dry reforming (CO₂/CH₄), oxi-CO₂ reforming (CO₂/CH₄/O₂) and bi-reforming (CO₂/CH₄/H₂O)), as well as current state-of-the-art steam reforming technology. Advancements in cost reduction and environmental performance are highlighted. While comparative studies on different plasma processing concepts have been published, their number is not large; meaning this study is bespoke in this aspect. Our study is also bespoke in terms of the extensive consideration of industrial gas separation, providing a holistic view on sustainability with an industrial viewpoint. Three different production design scenarios were considered in the analysis: DRM (scenario 1), oxy-CO₂ reforming of CH₄ (OCRM) (scenario 2), and bi-reforming of CH₄ (BRM) (scenario 3). This evaluation was carried out through techno-economic analysis and a cradle-to-gate life cycle assessment (LCA). Among the scenarios analysed, OCRM demonstrates the most favourable economic performance, leading to a unitary cost of production of $549 per tonne syngas, followed by DRM and BRM. However, when operating at large scale, the syngas production cost of BRM could compete with the benchmark if 20% reduction in plasma power consumption can be achieved, so in the near future, plasma-based BRM could be competitive against other more mature electric-powered technologies. When assessing environmental performance across 10 environmental categories of LCA metrics, OCRM is again preferred, followed by DRM and BRM. Key impact categories identified include freshwater eutrophication potential and energy consumption, which are significant contributors to environmental impacts. A study on the transition of energy sources indicates a substantial decrease in global environmental impact in the range of 50% when shifting from current electricity generation methods to wind energy sources. Comparative benchmarking reveals that the technologies evaluated in all three plasma scenarios perform better in environmental metrics across 7 over 9 categories assessed, when compared with current state-of-the-art steam reforming technologies. A material circularity indicator around 0.7 is obtained in all scenarios with slight differences, reflecting a medium-high level of circularity. Sectors such as chemicals and recycling manufacturing could greatly benefit from our findings on plasma-assisted methane reforming. By leveraging these technologies, the energy industry can facilitate a shift toward renewable energy sources, enabling cost-effective and environmentally friendly production.