A comparative evaluation of dark fermentative bioreactor configurations for enhanced hydrogen production

Energy from renewable resources has been growing in popularity, ultimately helping to reduce emissions of greenhouse gases (GHGs) and contaminants. Hydrogen (H₂), with a higher energy combustion output than hydrocarbon fuels, has been identified as a clean, sustainable, and environmentally friendly energy source. Producing biohydrogen (bioH₂) from renewable sources offers several benefits, including lower costs and increased sustainability.

Among the bioH₂ production processes, dark fermentation supports commercialization and scale-up for industrial applications. This paper examines various bioreactors, such as anaerobic sequencing batch, continuous stirred, up-flow, fixed-bed, and membrane reactors, along with their operational approaches for bioH₂ production. Additionally, a bibliometric analysis method is performed to identify historical and current developments in reactor configuration studies.

The paper addresses the main variables influencing reactor performance and methods for increasing process efficiency, considering economic and environmental aspects. The results revealed that continuously stirred reactors are widely utilized as a cost-effective configuration for bioH₂ production. Furthermore, membrane bioreactors and fixed-bed reactors yielded higher bioH₂ performance compared to other configurations. However, high energy consumption and costs highlight the need for further reactor development.

Finally, future recommendations to address critical problems in reactor configurations, gaps in the literature, and areas needing improvement are comprehensively reported.