A technique for continuous conversion of diene-containing aliphatic hydrocarbon feedstock to heavier hydrocarbon products wherein the feedstock is contacted at elevated temperature under endothermic high severity reaction conditions with a fluidized bed of acidic zeolite fine catalyst particles, comprising methods and means for:maintaining the fluidized catalyst bed in a vertical reactor having a turbulent reaction zone by passing vapor upwardly through the reaction zone at a velocity greater than dense bed transition velocity to a turbulent regime and less than transport velocity for the average catalyst particle;feeding a continuous stream of feedstock into the reaction zone, said feedstream comprising sufficient C.sub.3.sup.+ alkanes to require net endothermic reaction conditions;withdrawing a portion of coked catalyst from the reaction zone, oxidatively regenerating the withdrawn catalyst, heating the catalyst substantially above process temperature in the fluidized bed reactor, and returning hot regenerated catalyst to the reaction zone at a rate to control catalyst activity and reaction temperature under conditions of reaction severity to effect feedstock conversion to an aromatics-rich hydrocarbon effluent stream; andseparating an aromatics-rich product from the fluidized bed effluent stream.Aromatics yield is increased by recovering a recycle stream comprising C.sub.5.sup.+ aliphatic hydrocarbons from the fluidized bed effluent stream for further conversion in the fluidized bed to increase aromatics product yield.