Biogas purification - Eliminating VOCs and siloxanes

At a time when conditions are particularly favorable for the development of alternative energies to fossil fuels, the prospect of integrating biogas into the French energy landscape is of definite interest from a political, economic, and environmental standpoint. Indeed, the recovery of domestic, industrial, and agricultural organic waste and the treatment of wastewater are in line with the concepts of sustainable development and renewable energy applications, as clearly set out in recent international commitments and agreements. The environmental impact of implementing biogas recovery systems results in a significant reduction in greenhouse gas emissions. As methane has a greenhouse effect 20 to 30 times greater than that of carbon dioxide, it is preferable to recover energy from methane through combustion rather than releasing it into the atmosphere [G 1 815] . Fluctuations in the cost of importing fossil fuels are also contributing to renewed economic interest in producing energy from biogas, whether directly in the form of high-purity methane gas or after conversion into electricity .

Nevertheless, the optimal integration of this resource into existing energy networks is not without technical challenges. Gas dehumidification and hydrogen sulfide reduction are two key steps in the biogas treatment process. However, research on this topic in recent years has highlighted the pressure exerted by volatile organic compounds (VOCs) present in biogas on the operation of energy production facilities. Regardless of the recovery process used, the presence of these compounds at concentrations in the ppm (mg/m ³ ) range poses a risk of premature deterioration of the facilities, as well as a reduction in the energy recovery efficiency of...