Method and apparatus for the destructive distillation of oil shale

Claim 1

APPARATUS FOR DISTILLING OIL-BEARING SHALE AND SIMILAR SOLID CARBONACEOUS MATERIAL, COMPRISING: MEANS DEFINING A RETORT DIVIDED VERTICALLY INTO A PRELIMINARY HEATING ZONE, A PREHEATING ZONE BELOW THE PRELIMINARY HEATING ZONE, A DISTILLATION ZONE BELOW THE PREHEATING ZONE, AND A COMBUSTION ZONE BELOW THE DISTILLATION ZONE, SAID ZONES BEING IN OPEN COMMUNICATION WITH ONE ANOTHER SO THAT CARBONACEOUS MATERIAL FED INTO THE TOP OF THE RETORT CAN PASS FROM EACH ZONE DIRECTLY INTO THE NEXT ZOEN THEREBELOW; A FLUE GAS DUCT LEADING FROM THE COMBUSTION ZONE; A PRIMARY HEAT EXCHANGER IN THE FLUE GAS DUCT IN WHICH HEAT EXCHANGE FLUID MAY BE HEATED BY INDIRECT HEAT EXCHANGE WITH THE HOT FLUE GASES TO A TEMPERATURE AT LEAST AS HIGH AS THAT AT WHICH DISTILLATION OF THE CARBONACEOUS MATERIAL TAKES PLACE; A SECONDARY HEAT EXCHANGER IN THE DISTILLATION ZONE CONNECTED WITH SAID PRIMARY HEAT EXCHANGER TO ENABLE HEATED HEAT EXCHANGE FLUID TO IMPART ITS HEAT TO THE CARBONACEOUS MATERIAL BY INDIRECT HEAT EXCHANGE TO EFFECT DISTILLATION THEREOF: AN AIR PREHEATER IN THE FLUE GAS DUCT DOWNSTREAM FROM SAID PRIMARY HEAT EXCHANGER; MEANS FOR PASSING PREHEATED AIR FROM SAID AIR PREHEATER THROUGH THE CARBONACEOUS MATERIAL IN THE PREHEATING ZONE TO PREHEAT THE SAME BY DIRECT HEAT EXCHANGE THEREWITH; MEANS FOR CONDUCTING AIR WHICH HAS BEEN PASSED THROUGH THE CARBONACEOUS MATERIAL IN THE PREHEATING ZONE TO THE COMBUSTION ZONE TO TAKE PART IN THE COMBUSTION PROCESS; MEANS CONNECTING SAID FLUE GAS DUCT, AT A LOCATION DOWNSTREAM FROM SAID AIR PREHEATER, WITH SAID PRELIMINARY HEATING ZONE, AND FOR PASSING FLUE GAS ACROSS THE CARBONACEOUS MATERIAL IN SAID PRELIMINARY HEATING ZONE IN DIRECT HEAT EXCHANGE RELATION THEREWITH; AND MEANS FOR REGULATING THE RELATIVE PRESSURES OF THE AIR AND FLUE GASES PASSING THROUGH THE CARBONACEOUS MATERIAL AND THE DISTILLATION GASES IN THE DISTILLATION ZONE TO MAINTAIN SAID PRESSURES AT VALUES SUCH AS TO PRECLUDE THE ADMIXTURE OF FLUE GASES IN THE PRELIMINARY HEATING ZONE WITH DISTILLATE PRODUCTS IN THE DISTILLATION ZONE.