Kinetic Modeling of Methanol Synthesis - Impact of Catalyst Deactivation

Recently, we developed a new kinetic model for the methanol synthesis from H-2, CO2 and/or CO using a commercial Cu/ZnO/Al2O3 catalyst (Seidel et al., 2017), where different active surface species for CO and CO2 hydrogenation and dynamic changes of the catalyst morphology were taken into account. This effect is crucial for the description of the dynamic transient behavior. The model is therefore suitable for evaluating new applications in chemical energy storage, where strongly varying feed ratios of CO and CO2 are possible (Raeuchle et al., 2016). The model parameters were fitted to steady state and dynamic experimental data for varying CO/CO2 feed ratios (Vollbrecht, 2007) using global optimization. Identifiability was studied using the profile-likelihood method. In the present contribution, the effect of catalyst deactivation observed during the experiments is explicitly taken into account. For that purpose different catalyst activity levels are considered and parameters are refitted to the experimental data to achieve better quantitative prediction. Further, the influence of possible additional side reactions is discussed.