Waste Management Program for 1994-1995
Contact: Tom Robl
Associate Director, Waste Management Program
The principal emphasis of the Waste Management Program is to further the understanding of, and develop technologies for, the utilization and/or the efficient disposal of coal combustion by-products. The goals are to develop new solutions to the problems of combustion waste management, in close association with industry, and in so doing overcoming institutional, environmental and technical barriers to coal utilization.
Coolside Project: This project is a study of the elemental release characteristics of duct injection by-products (flue gas emission control), u sing material from a demonstration of the Coolside technology being conducted at an Ohio Edison power plant. The research is conducted in collaboration with CONSOL Inc. Research and Development, and is sponsored by the DoE and the Ohio Coal Development Office. Part of the project involves leaching studies under natural weathering conditions, using a four-chambered field lysimeter, with about 65 tons of material per chamber. Laboratory investigations use leaching columns to simulate the field studies. A specific objective is to try to develop low-cost, predictive methods for assessing leaching properties. The geotechnical characteristics of these materials are being investigated in partnership with UK's Civil Engineering and Transportation Research programs. The work addresses the effects of weathering on physical properties to assist in the design of safe and stable landfills. This project has been instrumental in determining the key mineralogical transformations which the materials undergo during weathering.
Another part of the project is concerned with the production of artificial aggregate via pelletization. The CAER's role is to analyze the mineralogy and chemistry of pellets made from fly and bottom ash produced by a circulating fluidized bed combustor (CFBC) and to undertake geotechnical testing. The results have been used to improve pellet durability and strength. A field trial of the materials was initiated in the spring of 1995. Artificial aggregate, along with natural aggregate, was used to pave a test section of asphalt-surfaced highway in Pennsylvania. Results of this demonstration look promising. In-house pelletization research is also proceeding with other types of FGD materials.
In the Haulback project, which is sponsored by the DoE and involves collaborative efforts with Costain Coal, the application of FGD materials as a structural fill in highwall mines is under investigation. The concept is to emplace dry FGD material in adits left by automated highwall mining. When wetted, the filler mixture sets like concrete and is capable of generating sufficient strength to support the roof, allowing additional coal to be extracted, and providing other advantages. Over the past year, the focus has continued to be on the measurement of geotechnical properties, where substantial progress has been made in unraveling the complex hydration reactions and mineralogical transformations of these materials.
Fly Ash Quality and Utilization: The presence of carbon in fly ash from coal-fired power stations presents marketing and technical obstacles to the use of fly ash as a cement substitute in concrete. The problem has been exacerbated by the installation of low-NOx burners. In conjunction with the East Kentucky Power Cooperative (KY) and the Tennessee Valley Authority (TVA), we have conducted investigations of the impact of low NOx burner conversion on fly ash quality. In this same context, we are examining a process for the separation of carbon to improve fly ash quality. We are also examining the possible uses of the materials that could be separated (e.g. carbon, micro-magnetite and cenospheres) and marketed as added-value products.
A cooperative research program in oil shale conversion was initiated in 1994 with PAMA (Energy Resources Development), Ltd., a research organization formed from a number of industries in Israel. In 1994, we completed a two-phase study to investigate the mechanisms of secondary cracking and coking processes that occur during oil shale pyrolysis.
The Applied Microscopy laboratory has continued to provide support services to the CAER programs, and to external organizations. Particular mention is made of a study that was conducted to investigate the petrography of fly ash and other coal combustion by-products, with emphasis on the forms of carbon in high-carbon fly ashes. Jim Hower manages the Applied Microscopy Laboratory and can be contacted in regard to the capabilities of the laboratory.