Thermogravimetry of selected American and Australian oil shales in inert dynamic atmospheres

Abstract

The pyrolysis profile for the U.S. Geological Survey SGR-1 Green River shale specimen is reported using computerized TG and DTG techniques. The thermal behavior of this specimen in dynamic nitrogen atmosphere is compared with that of a retort composite (spent shale) specimen obtained from one of the current thermal retorting processes. The quantitative differences between these two specimens are discussed in terms of the thermal retorting of shales from the Western United States. A carefully performed comparative study of the Australian Rundle, Glen Davis, and Alpha Deposits as well as the USGS-SGR-1 Green River specimen is also given here. Using the results of this study, the pyrolysis onset temperatures and temperatures at maximum pyrolysis rate were related to the type of organic maceral components of the shale specimens. These shales were also compared for total carbon, hydrogen, and nitrogen content by elemental analysis. A drilled core specimen from Western Colorado of known oil yield versus depth of seam was used to correlate the DTG pyrolysis peak area to the Fisher assay oil yield assignments. A method of precise assignment of DTG peak areas which is often overlooked is also demonstrated.