Technologies for biogas desulfurization - An overview of recent studies

Desulfurization is a critical process for biogas upgrading to biomethane, because hydrogen sulfide is toxic and corrosive. In this paper, we conduct a systematic review to check the most recent studies on desulfurization technologies and find trends, potentials, and limitations of each technique. The information of 51 articles published since 2015 was extracted, highlighting the maximum H2S removal efficiency, the highest inlet H2S concentration studied, and the duration of the experiment. Only 23 papers studied raw biogas, and just 10 reported full-scale tests. Other researchers performed their studies with commercial gases and laboratory or bench scales. In addition, it became clear that tests were performed in different conditions, which was an obstacle to comparing them in the same data visualization. However, it was still possible to get insights, and overall the highest efficiencies were observed in experiments with lower H2S concentrations. About 92% of the articles of this set report H2S removal efficiencies over 80%. The following tests stand out: a trickling filter system, biodesulfurization and bioscrubbing processes, a photocatalytic desulfurizer, and micro-aeration tests. Therefore, the present study has an overview of the most recent studies. After this process, it seems relevant to sort the papers by test scale and gas type in future studies.