Solvent Refined Coal Materials Research Articles

Comparative chemical composition and biological activity of single- and two-stage coal liquefaction process streams

Samples from several integrated two-stage coal liquefaction (ITSL) process streams were collected under both normal and off-normal operating conditions. Selected crude materials were tested for their ability to initiate tumorigenicity in the initiation/promotion assay in mouse skin. Crude materials and their chemical class fractions were assayed for microbial mutagenic activity in the standard Ames test with S. typhimurium TA98, and selected samples were also subjected to the Chinese hamster ovary mammalian cell assay for mutagenicity. Mass spectral and gas chromatographic—mass spectral (g.c.—m.s.) analyses were carried out on these materials. Results were compared with those for analogous materials from solvent refined coal (SRC) single stage liquefaction processes. In general, the ITSL distillates were of higher molecular weight, higher hydroaromatic content, lower nitrogen content and were somewhat less alkylated than the analogous SRC materials. Compared to the SRC coal liquefaction materials, the ITSL distillates and bottoms materials collected under normal run conditions were substantially less active in both the microbial and mammalian cell mutagenicity assays. These same materials were also less active than ITSL samples collected under off-normal conditions. G.c.—m.s. analyses showed that ITSL materials collected under normal operating conditions were substantially reduced in amino polycyclic aromatic hydrocarbon content when compared to both the off-normal ITSL, and SRC materials. Activity of the ITSL materials as initiators of tumorigenesis was greater than expected, based on results from the in vitro assays and not significantly different than that of the SRC materials. The higher initial boiling point of the ITSL distillates probably accounts for much of their greater than expected initiating activity compared to the SRC materials.

Barley growth in coal liquid and diesel liquid fuels from coal and oil: A comparison of potential toxic effects on Barley

The production of new liquid fuels from coal creates the potential for environmental releases of new products and waste materials via spills or leaching of material from waste storage areas. The chemical composition of these products and waste materials suggests possible toxic effects upon exposed plants and animals. In this study, barley was grown in field lysimeters containing three concentrations (0.07, 0.74, 7.421 m−2 equivalent to 80, 800, and 8000 gal/acre, respectively) of a sample product blend of Solvent Refined Coal (SRC) heavy and middle distillates. Three methods of soil amendment simulated possible spill clean-up alternatives: adding the coal liquid as a surface layer, as a subsurface layer covered by uncontaminated soil, or intermixed with the top 1 dm of soil. To permit comparison of the coal liquid with familiar commercial material, the study protocol was followed simultaneously in lysimeters amended with # 2 diesel fuel. Statistically significant reductions in grain yield were observed for both the SRC and diesel materials for all methods of soil amendment at concentrations equivalent to 0.74 and 7.421 m−2, and for the SRC material only when mixed with soil at a concentration equivalent to 0.071 m−2. Where differences between fuel types were observed, the coal liquid was consistently more toxic.

The effects of nitrous acid on the mutagenicity of two coal liquids and their genetically active chemical fractions

The Ames/Salmonella assay was used to determine the effect of nitrous acid on the mutagenicity of solvent refined coal (SRC) distillates and distillate fractions. The SRC materials consisted of the higher-molecular-weight, high-boiling distillates, the process solvent (PS) and heavy distillate (HD), and also included the basic tar and neutral tar chemical fractions derived from these 2 distillates. Nitrosation products of each of the SRC materials were less mutagenic than the distillates or distillate fractions from which they were derived (untreated materials); in most cases they were less than 10% as mutagenic as that observed in the starting materials. The mutagenicity of the SRC materials after nitrous acid treatment was directacting, whereas all mutagenicity associated with the untreated SRC materials was indirect and required metabolic activation for expression in the Ames assay system.