GB672080A - Improvements in or relating to the distillation of oil shale - Google Patents

Abstract

672,080. Distilling oil shale &c. STANDARD OIL DEVELOPMENT CO. May 9,1950 [June 21, 1949; June 21, 1949], No. 11493/50. Class 55 (i). In distilling oil shale &c. as a fluidized bed M<SP>1</SP>, the upward flow of gas containing entrained solids is obstructed above the surface Ll as by a second fluidized bed M<SP>2</SP> on a grid 14, built up predominantly of fines slightly larger than 20 microns which have penetrated the grid. A system of separators 22 in series returns material to the beds, the coarsest and finest particles being in the arrangement shown discharged to the lower bed and the intermediate sizes to the upper bed. The fluidizing medium may comprise steam, product tail gas, carbon dioxide, or air. Plant embodying a separate combustion chamber in which spent shale is burnt and returned to the retort provides in one form a two-section combustion chamber 50, the bottom bed being supplied with spent shale suspended in air through a line 35. Fresh feed may be conveyed by combustion products through a line 72 into a hopper 80 whence it is supplied to the upper bed M<SP>70</SP> of chamber 50 for preheating before feeding to the lower bed of retort 10. The burnt shale may be fed to both beds, cracking of distillation products in the upper bed being controlled by the amount of hot shale introduced. Bed M1 may be maintained at about 850-1100‹ F.; further heating of spent shale to 1200‹-1800‹ F. to recover ammonia and light fuel gases may be effected by indirect means, direct injection of oxygen-containing gas or recirculation of solids from a heater vessel. Specification 646,982 is referred to.