Consequence of microwave irradiation on reforming catalysts

Abstract

The aim of this paper is to point out the effects of microwave irradiation on the reforming catalysts reactivity and particularly on the selectivity in hexanes isomerization of a 0.2%Pt/AhO 3 catalyst. The in situ thermal treatments of the catalysts and the catalytic reactions are performed in a plug-flow system working under isothermal and isobaric conditions. The catalytic bed can uniformly heated by microwave irradiation by using a magnetron and wave guide. In an other way, the catalytic bed can be heated in a classical electrical oven. Before thermal treatments, the initial step of preparation is done by impregnation of y-Al 2 O 3 with hexachloroplatinic acid. Metal particles diameters are estimated from hydrogen chemisorption and particles distributions are obtained using electron microscopy. The catalytic tests (hexanes isomerization) either under classical heating or under microwave irradiation, are performed in such way that the total conversion is lower than 20%. When the catalyst's thermal treatment and the catalytic reactions are performed in a classical oven, the selectivity in isomers is 50%. When the thermal treatment of the catalyst and /or the reaction are performed under the electromagnetic field, the selectivity in isomers is increased to 80%. The isomer selectivity remains high even when catalysts are subsequently tested under classical heating conditions.