OVERVIEW

It has been generally observed that the primary focus of the studies on hydroprocessing of heavy feeds was on the development of more active catalysts with a high resistance to deactivation. The behavior of heavy feeds under specific hydroprocessing conditions, i.e., type of catalysts and catalytic reactor, the yield and quality of the anticipated products, etc., have been attracting attention as well. A number of the suitable experimental systems have been available for these purposes. These setups are also suitable for establishing database of the parameters which can be used for the selection of catalysts and the optimization of commercial operations. Several types of catalytic reactors have been used for this research. The type of reactor selected for testing influences reliability of the generated data. As it was indicated earlier, the choice of an optimal experimental system for testing the high asphaltenes and metals feed requires an additional attention compared with the system used for testing the VGO and HGO feeds. This issue has been addressed in the series of articles published by Bej et al. (94 97) and Pitault et al. (98).

The reactors for experimental research can be divided into two main groups, i.e., batch reactors and continuous reactors. They are available in various sizes. The cost of the reactors may increase with their size. The differences between the data obtained in the batch reactors and continuous reactors, under otherwise similar conditions, have been noted. In the case of heavy feeds, reliability of the data obtained in small...