Chemical and toxicological aspects of coal liquefaction and other complex mixtures

Abstract

Chemists, biologists, and ecologists at Battelle's Pacific Northwest Laboratories are developing a data base to aid engineers in the safe design of coal liquefaction process options. Objectives of this effort have been to (1) identify and evaluate long-term health and environmental issues, (2) evaluate options to permit environmentally acceptable design, and (3) assess risk to man and the environment from deployment of a large-scale coal liquefaction industry. Chemically complex materials produced by various coal liquefaction processes, and under various stages of process design and operating conditions, have been screened for potential health and environmental effects. Biologically active materials have been fractionated and rescreened. Chemical constituents of biologically active fractions have been identified, and the environmental fate of problematic agents is currently being determined. This approach, linking engineering and life sciences research, is also relevant to the development of other energy technologies and industries that produce chemically complex materials. Results indicate that full-boiling-range coal-derived liquids are generally more active than shale oil and petroleum crudes in biological and ecological test systems. Several biologically active agents have been identified, including primary aromatic amines (PAA), polynuclear aromatic hydrocarbons (PAH), and phenols. Some components of coal-derived materials are taken up by biota and metabolized. Hydrotreating, a refining or upgrading process, reduces PAA, PAH, and phenol content, as well as mutagenicity, carcinogenicity, and toxicity of coal liquids. Selective distillation restricts PAA and PAH content, as well as mutagenicity and carcinogenicity to high-boiling-range coal liquids. Other process conditions (i.e., extraction severity, catalyst age, etc.) and environmental factors influence chemical characteristics and biological activity of coal-derived materials. Eliminating toxic input of coal liquids to ecological test systems results in partial system recovery. Recent findings indicate that biological responses to a particular chemical agent vary, depending on whether that material is presented to the organism or environment as a pure compound or in a complex mixture. Thus, results of studies with pure compounds cannot be used alone to predict effects of complex mixtures. The research approach described here provides guidance to solve environmental problems before regulatory agencies require limitations or facility construction is completed, and costs of process changes are higher. This prospective strategy can be applied to the development of any technology or the environmentally safe utilization of any resource.