“Power to Gas” can represent one of the crucial solutions for storing excess renewable energy by converting electricity into hydrogen and combining it with CO2 through the Sabatier reaction. RSE has focused its research on ex-situ biomethanation, particularly using trickle bed reactors (TBR). In RSE’s “Biological Methanation” Laboratory in Milan, initiated during the previous research phase (PTR 2019-2021), the first reactor (R1) was successfully inoculated, and atmospheric pressure experimentation produced methane within 70 hours of inoculation.

Over the three-year research period (PTR 22-24), RSE initiated experimentation on the second reactor (R2), focusing on analyzing the effects of operating pressure on methane production and purity. At higher pressures, increased solubility facilitates the absorption of these gases, accelerating the biological methanation reactions.

During the transition to high pressure, the strategy employed allowed microorganisms to adapt gradually to the new operating conditions, incrementally increasing both pressure and feed rates. Monitoring hydrogen concentrations and pH management were crucial to ensuring high methane purity in the outgoing gas. The Methane Production Rate (MPR) estimation revealed a value of 4.6 m3 CH4/m3 of useful volume per day, indicating high system efficiency.

Despite the transient conditions related to CO2 solubility and pressure changes, the system demonstrated a robust ability to handle the required conditions for methane production through the biological pathway. The results provide a solid foundation for further operational optimizations and insights.

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