GB1491363A - Preheating oil shale prior to pyrolysis thereof - Google Patents

Abstract

1491363 Heating oil shale OIL SHALE CORP 25 July 1975 [29 July 1974] 31239/75 Heading C5E Crushed raw oil shale is heated by entraining in a hot gas in a first dilute phase fluidized bed (i.e. a gas lift zone) and the preheated oil shale is then passed through at least one further dilute phase fluidized bed; the preheated shale is heated in the final dilute phase fluidized bed to between 400 and 650‹ F. with hot flue gas and the partially cooled flue gas from the final bed is passed through an incineration zone, thereby incinerating the entrained oil shale fines and hydrocarbon vapours; the flue gas from the incineration zone is cooled and the cooled flue gas is used to heat oil shale in at least one of the dilute phase fluidized beds other than the final bed. Crushed raw shale is heated in a first dilute phase fluidized bed 10 and then passed through the second bed 12 and the final bed 22 and into the retort 30 in which it is heated by hot ceramic balls from a heater 14 to produce a shale oil vapour stream 48, processed shale solids 50 and cooled balls which are recycled to the heater 14. The flue gas 44 from the heater 14 is cooled with air 31 and used to heat the shale in the bed 22. The gas 23 leaving the bed 22 is passed through an incinerator 24 which has a heat recovery zone 24 (d) which cools the gas from 1400-1500‹ F. to 800‹ F. The shale in the middle zone 12 is heated with a portion 21 of the cooled gas from zone 24 and the raw shale is heated in the first zone 10 with a mixture of cooled gas 21 from the zone 24 and cooled gas 13 from the zone 12. In an alternative procedure, the gas 13 from the zone 12 is passed through a second incineration zone, cooled and then used in the first bed 10.