Processes for dehydrogenating alkanes and alkyl aromatic hydrocarbons

A process for upgrading a hydrocarbon, comprising:

• (I) contacting a hydrocarbon-containing feed with fluidized dehydrogenation catalyst particles in a conversion zone to effect dehydrogenation of at least a portion of the hydrocarbon-containing feed to produce a conversion effluent comprising coked catalyst particles and one or more dehydrogenated hydrocarbons;
• (II) separating from the conversion effluent a first stream rich in the coked catalyst particles and lean in the one or more dehydrogenated hydrocarbons and a second stream rich in the one or more dehydrogenated hydrocarbons and comprising entrained coked catalyst particles;
• (III) contacting the second stream with a first quench medium to produce a cooled second stream;
• (IV) contacting the cooled second stream with a second quench medium within a quench tower;
• (V) recovering a gaseous stream comprising the one or more dehydrogenated hydrocarbons, a condensed first quench medium stream, and a slurry stream comprising at least a portion of the second quench medium in a liquid phase and the entrained coked catalyst particles from the quench tower;
• (VI) recycling at least a portion of the condensed first quench medium to step (III);
• (VII) separating at least a portion of the entrained coked catalyst particles from the slurry stream to provide a recovered second quench medium stream and a recovered entrained coked catalyst particles stream;
• and
• (VIII) recycling at least a portion of the recovered second quench medium stream to step (IV).