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U.S. Department of Energy
Office of Scientific and Technical Information

Method for flattening the combustion zone in an in situ oil shale retort by the addition of fuel

Patent ·
OSTI ID:7079936

A secondary combustion zone is established and its location is controlled in a fragmented mass of particles containing oil shale in an in situ oil shale retort. A processing zone including a primary combustion zone is established in the retort by igniting a portion of the mass of particles. An oxygen-supplying gas is introduced into the retort to advance the processing zone through the fragmented mass. If the primary combustion zone is not substantially planar or has not progressed uniformly, a secondary combustion zone is established upstream of the primary combustion zone by introducing into the retort a retort inlet mixture comprising fuel and at least sufficient oxygen for combustion of the fuel at a temperature no greater than the primary combustion zone temperature. The secondary combustion zone is maintained at an upstream location and allowed to spread laterally through the fragmented mass, heating portions of such fragmented mass, to the self-ignition temperature of oil shale which spreads the primary combustion zone laterally across the fragmented mass at the upstream location. 48 claims.

Assignee:
EDB-84-106019
Patent Number(s):
US 4224990
OSTI ID:
7079936
Country of Publication:
United States
Language:
English