System for recovering oil from solid oil-bearing materials

Claim 1

A THERMAL PROCESS FOR TREATING RAW OIL-BEARING SHALE IN THE FORM OF SMALL LUMPS WHICH DECREPITATE WHEN HEATED WHICH COMPRISES THE STEPS OF FIRST PREHEATING SAID RAW SHALE BY PASSING IT DOWNWARDLY THROUGH A PREHEATING ZONE IN COUNTERCURRENT CONTACT WITH AN UPFLOWING FLUIDIZED BED OF HEAT CARRYING FINE SPENT SHALE SOLIDS DERIVED FROM A STEP LATER ON IN THE PROCESS, PASSING THE THUS PREHEATED RAW SHALE DOWNWARDLY TO THE UPPER PORTION OF A RETORTING ZONE, COUNTERCURRENTLY CONTACTING SAID PREHEATED RAW DOWNWARDLY MOVING SHALE IN SAID RETORTING ZONE WITH A SECOND UPFLOWING FLUIDIZED BED OF HOT SPENT FLUIDIZED FINE SHALE PARTICLES THEREIN TO SUPPLY HEAT SUFFICIENT TO RETORT THE OIL FROM SAID SHALE, REMOVING VAPOROUS PRODUCTS OVERHEAD FROM SAID RETORTING ZONE AS A SEPARATE STREAM SUBSTANTIALLY FREE OF SOLIDS, PASSING AT LEAST A PORTION OF SPENT FINE SHALE PARTICLES WITHDRAWN FROM THE UPPER PORTION OF SAID SECOND FLUIDIZED BED IN SAID RETORTING ZONE DOWNWARDLY TO A COMBUSTION ZONE, BURNING THE CARBONACEOUS RESIDUE ON SAID FINE SPENT SHALE PARTICLES IN THE COMBUSTION ZONE TO SUBSTANTIALLY INCREASE THE TEMPERATURE OF THE FINE SPENT SHALE PARTICLES, RETURNING THE THUS HEATED FINE SPENT SHALE PARTICLES FREE OF COMBUSTION FLUE GASES TO SAID RETORTING ZONE TO FORM SAID SECOND UPFLOWING FLUIDIZED BED THEREIN, PASSING ANOTHER PORTION OF SAID SPENT FINE SHALE PARTICLES WITHDRAWN FROM THE UPPER PORTION OF SAID SECOND FLUIDIZED BED IN SAID RETORTING ZONE DIRECTLY TO THE BOTTOM PORTION OF SAID FLUIDIZED BED OF FINE SPENT SHALE SOLIDS IN SAID PREHEATING ZONE TO SUPPLY HEAT THERETO AS THE FIRST-MENTIONED UPFLOWING FLUIDIZED BED OF FINE SPENT SHALE PARTICLES, WITHDRAWING SPENT SHALE SOLID PARTICLES FROM THE BOTTOM PORTION OF SAID COMBUSTION ZONE AND RECOVERING HEAT THEREFROM BY INDIRECT HEAT EXCHANGE WITH FINE SPENT SHALE PARTICLES WITHDRAWN FROM THE UPPER PORTION OF SAID FIRST-MENTIONED FLUIDIZED BED IN SAID PREHEATING ZONE TO HEAT SAID FINE SPENT SHALE PARTICLES AND PASSING AT LEAST A PORTION OF THE LAST-MENTIONED PARTICLES HEATED IN THIS MANNER DIRECTLY TO SAID FLUIDIZED BED OF FINE SPENT SHALE SOLIDS IN SAID PREHEATING ZONE TO SUPPLY HEAT THERETO.