Abstract: A process for the removal of trace quantities of polynuclear aromatic compounds from the vapor effluent of a hydrocarbon dehydrogenation zone containing normally gaseous olefinic hydrocarbons, trace mononuclear aromatic compounds and trace polynuclear aromatic compounds by contacting the hot vapor effluent of a hydrocarbon dehydrogenation zone with a cold lean liquid absorption stream to absorb at least a portion of the trace polynuclear aromatic compounds to produce a rich liquid absorption stream and a gaseous olefin-containing hydrocarbon stream having a reduced concentration of polynuclear aromatic compounds.

Abstract: The activity, selectivity and yield of a dehydrogenation process used to produce olefins from normal paraffin hydrocarbons having 2 to 5 carbon atoms per molecule is improved by the introduction of an essentially constant level of water into the inlet of two or more beds of dehydrogenation catalyst.

Abstract: A continuous method for regenerating deactivated catalyst particles in a regeneration zone through which the particles are downwardly movable by way of gravity-flow. Particles are initially introduced into an upper carbon-burning/halogenation zone wherein they are contacted, in a first section, with a first air stream and a first mixture of steam and a halogen, or halogen-containing compound. Partially regenerated/reconditioned particles are then contacted, in a lower second section, with a second air stream and second mixture of steam and halogen. From this two-sectioned, carbon-burning/halogenation zone, the catalyst particles flow via gravity into a drying zone wherein they are contacted by a substantially dry air stream.

Abstract: A continuous method for regenerating deactivated catalyst particles in a regeneration zone through which the particles are downwardly movable by way of gravity-flow. Particles are initially introduced into an upper carbon-burning/halogenation section wherein they are contacted by a first air stream and a halogen, or halogen-containing compound. Therefrom, the catalyst particles flow into a lower drying section, wherein they are contacted with a dry second air stream.