Engineering Thermochemistry and Process Technologies to Enable Gigaton‐Scale Sustainable Biochar Production

ABSTRACT Biochar is a sustainable carbon material whose production represents one of the few recognized carbon dioxide removal (CDR) pathways capable of delivering gigaton (Gt)‐scale atmospheric carbon sequestration. Developing industrial‐scale technologies for sustainable biochar production is pivotal for enabling global deployment and realizes its full potential. Although the fundamentals and applications of biochar have been extensively reviewed, reviews dedicated to large‐scale production technologies and process engineering remain limited. This work comprehensively evaluates thermochemical conversion technologies, pyrolysis reactors, demonstrated successful processes, scale‐up challenges, and opportunities for industrial biochar production. This review first outlines thermochemical conversion techniques, pyrolysis mechanisms, and key parameters governing biochar formation. It then critically discusses major reactor configurations, highlighting their respective strengths and limitations. It also novelly maps the global implementations of biochar technologies and showcases commercially validated pyrolysis processes. Major scale‐up challenges and pathways toward sustainable deployment, including heat and energy management, environmental impacts, application and market dynamics, and CDR benefits, are assessed. Finally, future research directions and engineering strategies required to advance next‐generation pyrolysis technologies and sustainable biochar production are identified. This review aims to provide an integrated framework to guide process innovation and accelerate the global deployment of biochar as a Gt‐scale CDR solution for climate change mitigation.