OP-II-3

OP-II-23TemperaturesensorsThe effluent gas is dried in a cold trapat ca. -15°C and then analyzed with on-InletOutletline gas chromatography. The unreactedliquid phase is collected in the cold trapand analyzed at the end of the experimentCatalytic bed in order to determine the methanolconversion. The temperature in thePorous glass disccatalytic bed is measured by two fiberoptic (FO) sensors placed in the centerFig. 1: Schematic view of the steamreforming reactor with two immersed fiber and close to the reactor wall (thick blueoptic probeslines). The probes are introduced in thereactor through a 2 mm O.D. capillaries in order to allow for change in the axial(vertical) position and thus temperature measurement in various heights. Theobtained temperature measurements are used to determine an average temperaturein the catalytic bed during the reforming reaction under steady-steady conditions.It has been observed that methanol conversion under microwave heating issignificantly higher than that achieved with conventional electric heating underapproximately similar bulk temperature conditions (Fig. 2). The observed effectcan be rationalized by the presence of hot spots formed at the metal catalystparticles, which are better microwave absorbers than the support itself. Thisimportant finding, which qualitatively holds over a range of operating conditions(different flow rates, steam-to-carbon ratios and temperature levels), impliessignificant benefits in terms of higher energy efficiency and improved process safety.Conversion of MeOH [%]1008060Microwave heatingConventional heating40200100 120 140 160 180 200 220Average temperature [ o C]Fig. 2: Methanol conversion vs. average reactor temperatureunder microwave and conventional heating.References[1]. Perry W. L., Datye A. K., Prinja A. K.,Brown L. F., Katz J. D. Microwaveheating of endothermic catalyticreactions: Reforming of methanol.AIChE Journal 2002, 48, (4), 820-831.[2]. Ioffe M. S., Pollington S. D., Wan J. K.S.,High-Power Pulsed Radio-frequency andMicrowave Catalytic Processes: SelectiveProduction of Acetylene from theReaction of Methane over Carbon.Journal of Catalysis 1995, 151, (2),349-355.[3]. Chemat-Djenni Z., Hamada B.,Chemat F., Atmospheric PressureMicrowave Assisted HeterogeneousCatalytic Reactions. Molecules 2007,12, (7), 1399-1409.143