Towards Flexible Large-Scale, Environmentally Sustainable Methanol and Ammonia Co-Production using Industrial Symbiosis.

Abstract

As industries face increasing societal and governmental pressures to adopt sustainable practices, the methanol (MeOH) and ammonia (NH3) sectors, significant contributors to greenhouse gas (GHG) emissions, are seeking innovative solutions to transition toward net-zero emissions. Here, we report on the use of industrial symbiosis (IS) as a transformative strategy to facilitate the cleaner co-production of MeOH and NH3 by integrating green hydrogen (H₂) within a carbon capture and utilisation (CCUS) flowsheet. We examined the environmental assessment of various co-production pathways, including six (6) business-as-usual (BAU) MeOH and NH3 co-production schemes (GHR-SMRBAU, SMR-SMRBAU, ATR-SMRBAU, GHR-ATRBAU, SMR-ATRBAU, ATR-ATRBAU) and six (6) hybridised (Hyd) IS flowsheets (GHR-SMRHyd, SMR-SMRHyd, ATR-SMRHyd, GHR-ATRHyd, SMR-ATRHyd, ATR-ATRHyd) utilising cradle-to-gate life cycle assessments (LCA). Results show that IS-integrated flowsheets reduced GHG emissions by 12-28% compared to BAU operations, with GHG impacts improving in the order GHR-ATRHyd >ATR-ATRHyd >SMR-ATRHyd > GHR-SMRBAU > ATR-SMRBAU > SMR-SMRBAU, in agreement with energy and resource efficiency results. Notably, the GHR-ATRHyd configuration outperformed all other cases, reducing natural gas consumption by 11% and heating requirements by 8.3%. Furthermore, sustainability results support IS as a pathway to environmental benefits- with ATR-based NH3 operations achieving up to 31% improved impacts linked to both ecosystem quality and human health. Ultimately, our study underscores the critical role of IS in advancing resilient, low-carbon practices, promoting sustainable technologies for net-zero emissions and defossilisation, thereby supporting a transformative shift towards sustainable industrial operations.