A quenching medium is delivered directly to selected regions or locations within a catalyst bed in a hydroprocessing reactor vessel in order to control the reactivity of a hydroprocess occurring in the selected regions or locations separately from other regions or locations. Temperature sensors for providing temperature indications and conduits for delivering the quench medium are distributed throughout the catalyst bed. One or more conduits can be selected for delivery of the quenching medium to selected regions or locations so that separate control of the level of reactivity in each of various regions or locations throughout the bed can be achieved.

The invention relates to hydrocarbon dehydrocyclization to produce products such as aromatic hydrocarbon, to equipment and materials useful for dehydrocyclization, to processes for carrying out dehydrocyclization, and to the use of dehydrocyclization for, e.g., natural gas upgrading. The dehydrocyclization is carried out in a catalytic reaction zone of a reverse-flow reactor.