OP-II-3

OP-II-20DESIGN OF MONOLITHIC REACTORSFOR CONTINUOUS LIQUID-PHASE HYDROGENATIONPROCESSESHaase S., Bauer T., Lange R.Technische Universität Dresden, Department of Chemical Engineering,01062 Dresden, Germany;e-mail presenting author: stefan.haase@tu-dresden.deRecent research has shown that monolithic reactors are promising to intensifymultiphase (gas-liquid-solid) reaction processes such as hydrogenations [1]. Theperformance enhancement results from several benefits of the uniform mini-structure,such as low pressure drop, low axial dispersion, high surface-to-volume ratio andeasy reactor scale-up [2]. Based on numerical simulations, several investigatorsrecommend the replacement of conventional catalyst particles by monolithic catalystsfor fast reaction processes, such as hydrogenations, to increase space-time yield andselectivity [3, 4]. These theoretical findings are supported by experimental studies forthe hydrogenation of diverse organic compounds in the liquid-phase [5]. The reactorperformance strongly depends on the gas bubble length and the liquid slug length. Inreaction studies reported, these parameters are roughly estimated or even unknown.Therefore, the optimal hydrodynamic conditions and consequently the maximumreactor performance are unknown, too. Furthermore, most of research work focusedon superficial phase velocities above 100 mm/s in order to achieve a more uniformphase distribution at the reactor inlet and to the avoid hydrodynamic instabilitieswhich can be caused by unfavourable gas-liquid mixing.This work will present a novel setup to study hydrodynamic parameters (gas andliquid slug lengths) and overall reaction rates at elevated pressures and temperaturessimultaneously for monolithic reactors. The gas bubble was formed inside thechannel by feeding the gas with needle injectors. The gas bubble and liquid sluglength at a given two-phase velocity was varied by the application of injectors withdifferent outer diameters ranging from 0.4 mm to 0.8 mm and measured at thereactor inlet and at the reactor outlet.In hydrodynamic studies, the range of superficial gas and liquid velocities toachieve slug flow for two-phase flow of alpha-methylstyrene and hydrogen has been136