Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

OP-I-12KINETIC STUDIES IN STRUCTURED REACTOR WITH THEFRAGMENT OF MONOLITH CATALYSTN.N. Sazonova 1 , S.N. Pavlova 1 , S.A. Pokrovskaya 1,2 , N.A. Chumakova 1,2 , V.A. Sadykov 1,21 Boreskov Institute of Catalysis SB RAS, pr. Akademika Lavrentieva 5, Novosibirsk, RussiaPhone: 007-383-3306878; fax: 007-383-3306878, E-mail: pokrov@catalysis.ru2 Novosibirsk State University, Pirogova st., Novosibirsk, RussiaThe kinetic study of high-temperature processes at relevant experimental conditions, inparticular, realized on monolithic catalysts at short contact times, is a complicated task whichdemands the use of special structured reactors of small scale. In analogy to the case ofmonolithic reactors for industrial applications, such model reactors allow to realize theinvestigations at high space velocities, and the impact of mass transfer, pressure drop andtemperature gradients along the catalyst length can be minimized. The advantages of annularand metallic plate-type structured reactors for kinetic measurements under severe conditionswere shown for the case of CH 4 and CO combustion over a PdO/γ-Al 2 O 3 catalyst [1]. Catalystunits for these reactors were prepared specially via coating some ceramic or metallic surfaceby a thin catalyst layer.In structured reactor used for the study of partial oxidation of methane (POM) into syngasover LaNiPt–catalyst, separate structured elements of a real monolith are tested in a quartztube at short contact times [2]. The aim of present work is the analysis of such structuredreactor behavior for a monolithic catalyst based on a honeycomb α-Al 2 O 3 support withtriangular channels.ExperimentalFor the purpose, the triangular fragments of a porous monolithic LaNiPt/α-Al 2 O 3 catalystwith one separate straight channel with wall thickness 0.2 mm, side of the channel 2.3 mm,and length of 10-20 mm were used for the experiments. Thus, the catalyst shape and structurecorresponded completely to a real catalytic system. The POM testing of the fragments wasperformed in a plug-flow quartz reactor of 4 mm ID at atmospheric pressure. The temperatureof the catalytic bed was varied in the range of 600-900 °C and controlled precisely by thinthermo-couples placed along the catalyst length. The reaction mixture contained 3–12 % ofmethane and 1.5–6 % of oxygen flowing with the rate in the range of 5–30 l/hour, i.e., at 4–15 ms contact time.Impact of inter-phase mass transferThe axial profiles of mass transfer rates between gaseous flow phase and the catalyst wallwere determined on the basis of the approaches developed for local Sherwood number in48