Comments on the Modified Fischer Assay of Eastern oil shales of Kentucky

The Modified Fischer Assay is the accepted method for evaluating the potential liquid fuel yield of an oil shale. For a given shale, percent of Fischer Assay oil yield has become the standard used for judging technologies. The method has been developed for and is well understood when applied to oil shales in the western United States. However, the assay can be successfully applied to eastern United States oil shales only if care is taken in several areas that prove less important for its successful application to western shales. In particular, standardized sample preparation and handling with minimum air exposure of pulverized shale is required; a well-controlled and reproducible heating profile during retorting must be employed; and consistently effective liquid product collection must be accomplished. These considerations have a major influence on assay accuracy. Only with care in these areas, can Modified Fischer Assays suitable for eastern shale resource evaluations and technology comparisons be obtained.