Studies for the stabilization of coal-oil mixtures. Technical progress report, December 1978-February 1979

Abstract

Efforts were focussed on the continued development of the bound rubber test for surface characterization of coal and of the characterization of the stability and rheological properties of coal-oil mixtures prepared from different coals with and without various additives. Two significant conclusions were based on the above work. First, differences between two types of bituminous coal were detected by the bound rubber test when the data were adjusted for the specific surface area of the coal samples. Bound rubber values for gels prepared from styrene butadiene rubber (SBR) and Illinois coal were measured to be 5%/m/sup 2//g while the value for gels prepared from SBR and Pittsburgh (NEPSCO) coal were measured to be 20%/m/sup 2/g. Secondly, the effect of a single additive on the stability and rheology of the COM varied for different types of coal, even for different coals within the same rank. For example, ES 7071, the nonionic surfactant supplied by BASF, Inc. which is to be used in the COM for the NEPSCO demonstration, was tested with both some Pittsburgh coal (from NEPSCO) and some Illinois coal. With the Pittsburgh coal, the COM was determined to be sedimentatively stable; however, the COM prepared with the Illinois coalmore » did settle and the viscosity of the settled bed region increased tremendously over the increase which would be expected based on the increase in solids concentration. At this point insufficient data exist to establish a connection between the two conclusions made above.« less