Model application to a lab-scale thermophilic hydrogenotrophic methanation system

Abstract

The thermophilic hydrogenotrophic methanation (THM) is a well-known biochemical process by means of which hydrogen and carbon dioxide can be converted into methane. Compared to chemical catalytic methanation, THM showed an obvious advantage with a low operation cost and high flexibility. However, the THM processes are often operated with specific microorganisms, which require very specific conditions. The requirement of those specific methanogens increases the difficulty of THM operation. In this study, a modified anaerobic digestion model no. 1 (ADM1) was applied to describe the performance of a lab-scale THM system. A series of experiments were conducted to evaluate the methane conversion efficiency of THM, while a lab-scale THM system was operated at the same conditions. The model simulation showed a good data fitting performance compared to measure data after the model was calibrated with 30-day input data from the lab-scale reactor, while the mean relative error (MRE) was 14.2%. The hydrogenotrophic methanation model (HMM) was also applied for the model predictive control (MPC) test in the lab-scale reactor, where the prediction accuracy was confirmed with 10–18% MRE. The results indicated the potential of HMM to be applied further in big-scale THM processes.