Recovery of fuel from oil shale

摘要

Raw shale is supplied to a pyrolyzer where it is pyrolyzed by fuel gas and hot spent shale derived from a gasifier. Typically, the raw shale is Eastern U.S. shale and the pyrolyzer includes a fluidized bed. The pyrolyzed shale having given up its oil and volatile hydrocarbons, rises to the top of the fluidized bed of raw shale where it is transferred to the gasifier. Oxygen and steam are supplied to the gasifier. This composite gas reacts with the carbon of the pyrolyzed shale in a fluidized bed to produce synthesis or fuel gas. The oxygen is supplied in such quantities as not to react completely with the carbon in the pyrolyzed shale. The steam reacts with the excess of carbon. Predominantly hydrogen and carbon monoxide are produced; in addition there is a smaller quantity of carbon dioxide and methane. This hot fuel gas is transferred to the pyrolyzer. In addition, hot spent shale is transferred to the pyrolyzer. The hot fuel gas fluidizes the raw shale in the pyrolyzer. The hot gas and the hot spent shale heat the raw shale separating the shale oil and product gas including volatile hydrocarbons. The oil is condensed and collected, the fuel gas is collected for utilization in the above process and also for other purposes.