Occurrence and reactions of oil shale sulfur

We first discuss the nature and abundance of sulfur forms in Green River oil shale. A previously reported correlation between sulfur and grade does not work well over a very large geographical region. We next discuss the distribution of sulfur in the pyrolysis products, including trace sulfur species in the gas, and the reactions of steam and air with iron sulfides in the shale. Steam reactions increase H2S generation in both laboratory and pilot retort experiments. There is a related decrease in COS production with steam. We also discuss the contribution of sulfur to process heat and demonstrate the effectiveness of sulfate-forming reactions to minimize SO2 emissions during combustion of retorted shale under conditions simulating lift-pipe burners. The information presented should be of value for properly considering the effects of sulfur when designing oil shale processes.