摘要 |
An improved method of in situ retorting of oil shale wherein a cavern of crushed shale is created within an oil shale deposit, preferably by igniting a powerful explosion within the oil shale deposit, thereby creating a localized area or cavern of rubblized oil shale. Combustion gases are injected into the bottom of this cavern and particulate material, preferably a cracking catalyst, is deposited into a void at the top of the cavern and allowed to trickle down and fill the voids in the rubblized cavern. The oil shale is ignited at the bottom of the cavern and a combustion zone proceeds upwardly while the particulate material is caused by gas flow to percolate downwardly. A fluidized bed of particulate material is thereby formed at the combustion zone providing a controlled, evenly advancing combustion zone. This, in turn, efficiently retorts oil shale, provides increased recovery of hydrocarbon while simultaneously producing a catalytically cracked volatile, high octane gasoline exiting from the top of the retort.
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