Potential of chemical looping for green hydrogen production from biogas: process design and techno-economic-environmental analysis

Hydrogen (H2), as the promising alternative to fossil fuel-based energy carriers, faces the critical challenge of diversifying its sources and lowering production costs. Biogas, produced from organic waste, offers a renewable and carbon-neutral option for H2 production, but its high CO2 content requires a pre-separation process of CO2 from CH4 or specialized catalysts for use in existing reforming processes. Chemical looping reforming (CLR), as an advanced H2 production process, uses an oxygen carrier (OC) as the oxidant, allowing raw biogas to be used directly in the reforming process. Recently, numerous studies on CLR design and analysis have demonstrated their growing economic feasibility. However, deploying the CLR process in the biogas treatment industry requires further research to analyze its technical, economic, and environmental performance under target capacities and H2 purity. This study proposes biogas-based CLR processes and analyzes the capability of the processes from techno-economic and environmental perspectives: ?) chemical looping partial oxidization (CLPO), ?) chemical looping steam reforming (CLSR), ?) chemical looping water splitting (CLWS), and ?) chemical looping CO2 splitting (CLCS). Evaluation metrics include energy efficiency, exergy efficiency, unit production cost (UPC), and net CO2 equivalent emission (NCE) to compare technical, economic, and environmental performance, respectively. Each process is simulated in Aspen Plus to obtain mass and energy balance data. The heat exchanger network (HEN) is optimized to maximize heat recovery and achieve autothermal conditions. As a result, we comparatively analyze the economic and environmental capability of the proposed processes by identifying the major cost drivers and CO2 emission contributors.