Life cycle assessment (LCA) of catalytic processes for conversion of methane to hydrogen and carbon nanotubes

The STORMING project (Structured Unconventional Reactors for CO₂-Free Methane Catalytic Cracking) aims to develop reactors that convert biomethane into hydrogen and carbon nanotubes without producing direct CO₂ emissions, with potential applications in electronics and biomedicine. This thesis presents a preliminary Life Cycle Assessment (LCA) of the methane conversion process within the STORMING project, currently at Technology Readiness Level (TRL) 3 - 4, indicating it is in laboratory validation. It compares five catalyst production methods used by the research groups. The University of Bologna used co-precipitation with hydrogen reduction and non-reductive pretreatments, while the University of Seville employed mechanochemistry for two catalysts with similar pretreatments. The University of Zaragoza utilized the citrate method to produce a single catalyst with non-reductive pretreatment. The study is organized into two main segments: catalyst preparation and the methane reaction phase. It assesses the production of pre-treated versus non-pre-treated catalysts, and compared the catalyst productions environmental burdens, showing that non-pre-treated catalysts have lower environmental impacts due to reduced energy input. Among the non-pre-treated catalysts, the mechanochemistry method shows a disadvantage due to its high energy consumption at this scale of production. The impacts of the reactions performed with the catalysts depend highly on their productivity. Although non-reductively pre-treated catalysts require an initial activation period at the start of the reaction, they ultimately exhibit better productivity, resulting in lower environmental burdens. Using SimaPro software, the LCA evaluates the environmental impacts across different life cycle stages, identifying critical factors for enhancing sustainability. This foundational analysis aims to guide future advancements toward a greener and more efficient hydrogen production process.