Gas separation in industrial bulk chemistry and relevance for transitioning to industrial plasma chemistry

This is the authors' abstract. We don't add key points for this paper.

Products of the chemical industry shape our daily lives and are in a transition towards increasing use of renewable resources and energy. Bulk chemistry is governed by the development and adoption of advanced gas separation technologies, as the corresponding reactions are not highly selective and require extensive work-up. Bulk-chemical separation is the key to optimise reaction efficiency, ensure product purity, and enhance economic and environmental sustainability. This review critically evaluates established bulk-chemical separation methods such as (cryogenic) distillation, membrane separations, pressure swing adsorption (PSA), and chemical looping, and evaluate their application in industrial settings. Each technology is analysed in terms of operating principles, industrial maturity, energy demand, scalability, and compatibility with plasma-specific characteristics such as low conversion, high energy consumption, moderate operating temperature and pressure windows, fluctuating operation, and decentralised production. These separation technologies are a key enabler for the introduction of new, emerging reaction technologies, such as plasma-assisted chemical processes. Plasma processes are recognised for their potential to enable cleaner, more efficient chemical production, and, therefore, have potential to reshape bulk-chemical industry. Despite extensive investigations on plasma reactions in the past two decades, the enabling potential of separation for plasma processes has hardly been tackled. Therefore, this review aims to fill that gap and substantiates the potential of separation by one plasma process study at bulk-scale. Apart from providing perspective (forecast), concrete quantified evidence is given by a case study on plasma-assisted bi-reforming of methane (BRM) for high-purity syngas production is presented, integrating a revisited SMR-DMR benchmark with an original bulk-scale process model, to investigate the capacity of further scale-up towards bulk-chemical separation. Overall, this review demonstrates that separation technology must not be treated as a downstream add-on, but rather as a core design driver that fundamentally shapes the feasibility, efficiency, and scalability of industrial plasma chemistry.