Abstract: A process for the preparation of an olefins-containing mixture of hydrocarbons, which process comprises contacting a hydrocarbonaceous feedstock with a zeolitic catalyst at a temperature above 480.degree. C. during less than 10 seconds, whereby the zeolitic catalyst comprises a mixture of a zeolite I and a zeolite II in a matrix, wherein zeolite I has a pore diameter of 0.3 to 0.7 nanometers and zeolite II has a pore diameter greater than 0.7 nanometers, and wherein the catalyst contains at least 25% by weight of zeolitic material. The invention further relates to a catalyst composition comprising a mixture of a zeolite I and a zeolite II in a matrix material, wherein zeolite I has a pore diameter of 0.3 to 0.7 nanometers, zeolite II has a pore diameter greater than 0.7 nanometers, and the composition contains at least 25% by weight of zeolitic material.

Abstract: A device for introducing a hydrocarbon into a riser reactor containing a tubular diluent gas conduit having an interior surface and exterior wall surface where the interior wall surface is for passing a diluent gas into the reactor and two or more tubular hydrocarbon supply conduits, longitudinally perforated, arranged within the tubular diluent gas conduit where the longitudinal perforations are adapted to pass the diluent gas from the tubular diluent gas conduit into the tubular hydrocarbon supply conduit.

Abstract: Process for upgrading a sulphur-containing feedstock consisting of a hydrocarbon mixture substantially boiling in the gasoline range which process consists of subjecting the feedstock to a reforming step and subsequently to a hydrotreating step, and recovering from the hydrotreating step a product substantially boiling in the gasoline range and having increased aromaticity and decreased sulphur content.