Green Methanol as Bridge to SAF: A Solar-Driven Process using Unabatable Industrial Emissions

Abstract

Sustainable aviation fuels (SAF) are a promising alternative to decarbonize the aviation sector. A possible way to produce SAF is through green methanol, which requires green hydrogen and CO2. Cement industry can be a possible supplier of CO2, as it faces significant challenges in decarbonization. As a key industrial sector, cement contributes 2.5 Gt CO2-eq annually (8% of global emissions), with 60% of emissions arising from process-based reactions that remain unresponsive to electrification. This study proposes an integrated solar-driven process based on a thermochemical cycle (TCC) for H2 and CO co-production, synergistically paired with carbon capture (CC) to maximize CO2 utilization. The CC unit was modeled in Aspen Plus® and utilizes a novel amine solvent (CESAR 1) to capture CO2 from the direct emissions of the cement industry, considering the necessary conditioning for both short-distance utilization and long- distance transport (aiming long-term storage or other valorization pathways). The solar-TCC unit has been modelled using Python, based on meteorological data from Perth, Australia. This location is chosen as it has an existing cement industry and favorable solar irradiation. This unit produces both H2 and CO for the downstream production of methanol. High-temperature waste heat (>400 °C) from the TCC unit is repurposed to partially offset the CC unit’s thermal demand, enhancing overall efficiency. The integrated system enables scalable unit sizing, facilitating higher CO2 conversion rates for methanol synthesis. By leveraging concentrated solar energy and captured industrial CO2, this approach presents a sustainable pathway to decarbonize at the same time both cement production and aviation fuel synthesis.