ISBN 9783843939898

978-3-8439-3989-8, Reihe Verfahrenstechnik

Jonathan Lefebvre
Three-phase CO2 methanation Methanation reaction kinetics and transient behavior of a slurry bubble column reactor

192 Seiten, Dissertation Karlsruher Institut für Technologie (2019), Softcover, A5

Zusammenfassung / Abstract

The objective of this PhD thesis was to understand and predict the behavior of a slurry bubble column reactor (SBCR) operated under transient CO2 methanation condition. For this purpose, a SBCR simulation tool based on detailed experimental and literature data was developed. It was used to design a SBCR for Power-to Gas (PtG) application using a biogas as carbon source and H2 from a PEM electrolyzer.

In this work, the experimental work focused on the determination of the CO2 methanation product solubilities in dibenzyltoluene (chapter 4), as well as on the determination of a kinetic rate equation describing the three-phase CO2 methanation reaction kinetics (chapter 5 and 6). Hereby, special attention was paid on the understanding of the liquid phase influence on the catalytic CO2 methanation. First, a commercial catalyst was chosen after testing several commercially available catalysts for three-phase CO2 methanation (chapter 5). Then, the CO2 methanation reaction rate was investigated with several suspension liquids (chapter 5), as well as in absence of liquid (chapter 6). Based on these experiments, the impact of a liquid phase on the CO2 methanation reaction kinetics was clarified. Furthermore, a kinetic rate equation describing the kinetics of the three-phase and two-phase CO2 methanation was derived from these experiments. Finally, a transient modeling of a catalytic CO2 methanation SBCR was carried out based on experimental data gathered in chapters 4 and 5, as well as on literature data related to hydrodynamics and mass and heat transfer within SBCR. Next to this simulation, a transient modeling of a tube bundle reactor (TBR), i.e. the type of CO2 methanation reactor installed in the benchmark PtG facility in Werlte (Germany), was performed. To conclude, results from steady-state and transient SBCR and TBR simulations were compared to assess the performance of a SBCR for catalytic CO2 methanation (chapter 7).