to enhance the discharge of the spent contents to flow out rapidly or even gush out when the appropriate pressure in the depressurizing cycle is obtained the bottom of each reactor is opened so the fluidized high temperature 900 u00b0 f bed will flow freely out of the reactor to the fluid bed heat exchanger to transfer its sensitive heat to recycle hydrogen the recycle hydrogen stream will be heated from 100 u00b0 f to 700 u00b0 f and the spent shale or sands will be cooled from 900 u00b0 f to 200 u00b0 f to facilitate the continuous process remote controlled motor driven valves or cocks not shown are used at the bottom of each of the reactors and upstream of the associated heat exchanger the activation of each remote control valve or cock may be done manually or it may be automatically controlled by pressure near the bottom of each of the reactors the discharged spent oil bearing material is conveyed to a heat exchanger of the design shown in fig4 the heat exchanger 400 contains sections 402 404 and 406 maintained at 800 u00b0 f 500 u00b0 f and 200 u00b0 f respectively spent shale at 900 u00b0 f is introduced into heat exchanger 400 through line 408 recycle hydrogen at 100 u00b0 f is injected through line 409 flue gas is injected into heat exchanger 400 through flow lines 410.