Separation of rock solids from heat carriers in an oil shale retorting process

摘要

In an oil shale retorting process, hot heat-carrying solids are cycled to a retort zone to mix with and retort crushed oil shale, thereby producing gas, oil products, and a mixture of heat-carrier solids and spent shale solids. The spent shale solids contain some rock solids which have a heavier particle weight than the heat-carrier solids. The heat- carrier solids are separated and recovered from the spent shale for recycle through the process. In one stage of the separation procedure, a mixture of heat-carrier solids and rock solids is fed to a gas fluidized bed classifier which is constructed and operated in a way such that rock solids are preferentially separated from the heat-carrier solids. The separation stage is especially suited to spherically-shaped heat-carrier solids in a size range between about 0.14 centimeters (0.055 inch) and 1. 27 centimeters (0.5 inch) and having a surface area of between 10 and 150 square meters per gram.