Relationship between coking pressure generated by coal blends and the composition of their primary tars

Four coals that develop different pressures during the coking process were selected together with 10 blends (7 binary and 3 ternary) prepared with the same coals. Their semicoke contraction/expansion was measured by means of two tests (the Koppers-INCAR and the sole heated oven) and the variation in coking pressure during coking was determined in a movable wall oven. The coals and blends were then pyrolysed and the tars were analysed by gas chromatography (GC-FID–MS). The additivity law was applied to the properties used to evaluate the dangerousness of the blends and to the composition of the tar produced from the blends. Afterwards, the composition of the tar was studied in relation to contraction/expansion and the coking pressure generated by the coals and blends.