Abstract: Apparatus for controlling pressure in a combination hydrodesulfurization and reforming process wherein the pressure of a hydrogen-rich gas source from the reforming process is adjusted by coordinately manipulating a vent control valve for the hydrodesulfurization process and a vent control valve for the reforming process in a manner that insures maximum utilization of available hydrogen for desulfurization before any of the hydrogen from the reforming process is vented through its own vent valve.

Abstract: The pressure of a source of hydrogen-rich gas, which is generated at an elevated pressure as a by-product in a reforming process, is controlled by manipulating two vent valves so as to permit maximum utilization of the hydrogen-rich gas in a hydrodesulfuration process which consumes hydrogen in its operation. Control action to maintain the pressure of the source of hydrogen-rich gas requires that hydrogen-rich gas generated in the reforming process, which must be vented to reduce pressure, is vented through a hydrodesulfurization reactor in ample quantity for operation of the hydrodesulfurization reaction, and only that amount of hydrogen-rich gas which cannot be utilized in the hydrodesulfurization reactor is vented directly from the source of hydrogen-rich gas.