Numerical modelling and performance studies of the original and advanced TEMKIN reactor in laboratory scale testing of industrial egg shell catalysts for the selective hydrogenation of acetylene

•Development of an advanced version of the TEMKIN reactor for direct testing of egg shell catalysts.•Modelling of the complex mass and heat transport by COMSOL Multiphysics®.•Validation by pulse tagging and catalysis experiments.•Simulations point out transport limitations in the original TEMKIN reactor. Strong interactions between reaction kinetics and transport phenomena force the use of specialised reactors for catalysis experiments. Our working group developed an advanced version of the so called TEMKIN reactor by Temkin and Kulkova (1969), intended for the direct testing of industrial catalysts, e.g. egg shell catalysts used for the selective hydrogenation of acetylene. This work is dealing with modelling of the complex mass and heat transport to investigate and evaluate the influence on the reaction kinetics. Modelling was done using the commercial modelling software COMSOL Multiphysics® and was successfully validated by pulse tagging as well as catalysis experiments. Due to the flexible coupling possibilities in COMSOL, modelling distinguishes between the free gas phase, catalytically active porous shell and inert porous core of the catalyst pellets, ab initio depicting inner as well as outer mass transport limitations. Simulations confirmed good isothermal conditions in both reactor versions, but point out significant transport limitations in the original TEMKIN reactor due to dead zones near the catalyst pellets. Although direct numerical modelling is still challenging due to high computational demands, this work was able to show up its potential in studying laboratory scale reactor designs and catalytic systems.