GB673439A - Improvements in or relating to the distillation of oil-bearing minerals - Google Patents

Abstract

673,439. Distilling shale. STANDARD OIL DEVELOPMENT CO. April 14, 1950 [June 16, 1949], No. 9283/50. Drawings to Specification. Class 55 (i). In a fluidized process for distilling oil shale or the like in which the heat required for the distillation is supplied by burning the spent shale from the distillation zone in a separate fluidized heater and returning hot combustion residue to the distillation zone, the average carbon concentration in the distillation zone and in the heater is maintained below 0.7 per cent by weight, thereby to reduce entrainment of particles having a size of less than 20Á. The residue circulated from the heater to the distillation zone is preferably substantially carbon free and the circulation rate lies between 5-20 lbs. of residue per lb. of fresh shale charged. A proportion of the spent shale from the distillation zone may be discarded according to the heat requirements of the system or alternatively where the heat generated in the heater is in excess of that required for the process a cooling fluid, for example water, may be circulated through a coil disposed within the heater. The distillation zone is maintained at a temperature pf 900-1200‹ F preferably 950-1100‹ F., and the amounts of spent shale from the distillation zone rejected and fed to the heater respectively may be controlled automatically by a thermocouple disposed within the heater and arranged to operate suitable slide valves.