Effect of Process Parameter on Coal Tar Distillate Products

Coal tar pitch is broadly classified into two kinds based on their properties: Binder Pitch for aluminum and Graphite Industry Impregnated Pitch with less than 0.5% QI (Quinoline Insoluble) used in the graphite industry. To maximize value realization through downstream processing of coal tar, proposal was made to explore the feasibility of conversion of different qualities of coal tars from different steel plants to coal tar pitch (CTP) of different varieties (binder as well as zero QI impregnated for both Al & graphite industries), through first level of fractional distillation. In this study, four qualities of coal tar samples three from plant 1 (TP-1, TP-2, and TP-3) and one from plant 2 (TP-4) were collected and sent to laboratory for necessary evaluation, conversion and subsequent characterization studies. Zero QI impregnated pitch from coal tar (TP-1, TP-2, and TP-3) can also be made using solvent extraction or sedimentation process, which may not be cost-effective. Depending on the required specifications for binder & impregnated grade pitches, process parameters during vacuum distillation, were optimized through this collaborative work. On conversion of coal tar sample into coal tar pitches, QI content depends on distillation temperature, vacuum and soaking time.