ABSTRACT
Delft University of Technology, Faculty of Chemical Technology and Materials Science, Julianalaan 136, 2628 BL Delft, The Netherlands
b Unilever Research Port Sunlight Laboratory, Quarry Road East, Bebington, Wirral L63 3JW, United Kingdom
° to whom all correspondence should be addressed, e-mail: J.PJanssens@stm.tudelft.nl
INTRODUCTION
Alumina supported nickel catalysts are used in petrochemical and refining processes, for example in pyrolysis gasoline hydrogenation. The conversion of di-olefinic hydrocarbons into mono-olefinic hydrocarbons is necessary to prevent the formation of undesired gums and resins. However, the hydrogenation reaction has to be selective because hydrogenation of mono-olefines result in a reduction of the octane number of the gasoline. In order to obtain the desired selectivity nickel has to be (partially) sulfided. In general, three different procedures can be applied to sulfide and activate hydrotreating catalysts [1]: (1) Reduction of the oxidic catalyst precursor followed by sulfiding; (2) Simultaneous reduction and sulfiding of the oxidic catalyst precursor; (3) Sulfiding of the oxidic catalyst precursor followed by reduction. Also, the nature of the activation molecules can be various. For the sulfiding step a spiked feed or pure sulfiding agents such as thiophene, H2S, dimethyldisulfide and CS2 can be employed. For the reduction step H2 is generally used.
