UPGRADING OF PITCH PRODUCED BY MILD GASIFICATION OF SUBBITUMINOUS COAL

Alternative sources of anode binder pitch may be required in the future. One potential process for the production of pitch is low-temperature coal pyrolysis or mild gasification. Characterization data for a pitch produced by mild gasification of Powder River Basin subbituminous coal are reported. This pitch has acceptable sulfur, sodium, ash, and beta-resin levels but is shown to be deficient in aromatic carbon content and quinoline insolubles (QI). It also contains high levels of oxygen which leads to a high softening point and low coking value. Several strategies for upgrading this pitch to meet anode binder standards were investigated. These included heat treating, air blowing, solvent extraction, vacuum distillation, and addition of artificial QI. The addition of artificial QI (carbon lampblack) was the most successful of the methods investigated.