A comprehensive review of advancements and challenges in hydrogen production from thermochemical and biological conversion of food waste: The path forward

Abstract

The environmental impact of food waste, estimated at approximately 1.3 billion tons per year globally, is alarming and requires urgent attention. Similarly, with energy demand expected to rise to approximately 568 Mt of H₂ by 2050, there is a growing appeal within the scientific community to develop alternatives to fossil fuels, which are major contributors to global warming. Hence, significant efforts are being directed towards advancing current food waste conversion technologies and exploring novel approaches that could potentially replace the less efficient methods in the near future. The current review aims to provide state-of-the-art developments and upgrades in thermochemical (pyrolysis, gasification, intermediate processes such as torrefaction, and hydrothermal carbonization) and biological (fermentation) conversion technologies supporting hydrogen production from different food wastes. Notably, household food waste has shown more potential compared with synthetic factory prepared sources. The influence of different operating parameters, pre-treatments, and additives or catalysts supporting food waste conversion to hydrogen are mentioned. This review indicates that hydrothermal carbonization and torrefaction show promise in producing intermediate products, which can then be further processed through pyrolysis and gasification to generate energy. Gasification is found to be more promising and mature technique than pyrolysis and fermentation. This review also highlights the challenges encountered in these technologies and provides a way forward for future research and developments. Moreover, the conclusive remarks are provided for this review.