WASHINGTON, DC - Through a cooperative agreement with the Office of Fossil Energy's National Energy Technology Laboratory (NETL), a team headed by West Virginia University (WVU) has developed and successfully demonstrated a synthetic binder pitch that uses hydrocarbons from coal to supplement or replace petroleum feedstocks. The new binder pitch, and similar coal-derived products, could potentially reduce America's dependence on imported oil.
Binder pitch - a carbon-rich, tar-like material - is an important ingredient in making graphite rods used in electric arc furnaces for the manufacture of steel from scrap. Conventional binder pitch usually blends petroleum pitch with standard coal-tar pitch. The new synthetic pitch could replace at least 19,000 tons of conventional pitch needed each year by graphite electrode manufacturers. WVU claims that the same pitch could be used by the aluminum industry; if so, demand for the new product would be close to one million barrels per year.
"Oftentimes, the discussion about America's reliance on imported energy focuses on fuels such as gasoline and diesel," said Al Stiller, a WVU faculty member and part of the engineering team that developed and produced the synthetic pitch. "But in reality, we need to also consider pitches and cokes, which are equally important to the American economy."
Producing the synthetic pitch employs a solvent-based continual coal-extraction process. Solvent extraction of coal is an environmentally-friendly way to tease out coal's hydrocarbons, which can then be turned into useful products. Deriving binder pitch via this process uses much less coal than the standard method of distilling it from coke-oven tar. About 1,500 pounds of pitch can be produced from one ton of coal using the new process, whereas only about 60 pounds is produced from every ton of coal via the standard method.
WVU and NETL teamed with GrafTech International Ltd. and Koppers Inc. to manufacture full-scale (20-inches diameter and 96 inches long) graphite electrodes containing the synthetic pitch and test them at a commercial electric-arc steelmaking furnace. The testing, which occurred in Georgetown, S.C., found that substituting synthetic pitch for the petroleum-based component of commercial binder pitch resulted in no significant differences in the electrodes' performance. Analysis of the electrodes after manufacture also showed no significant difference from the electrodes made with the standard pitch blend.
The new binder pitch is the first of what is hoped will be many economical coal products derived through the new extraction process. As this line of research continues, other products are being investigated, such as an all-coal-derived graphite electrode that will use domestic coal instead of feedstocks from petroleum.