Effects of quinoline-insoluble particles on the elemental processes of mesophase sphere formation Original Research Article

Quantitative evaluation was made on effects of primary quinoline insolubles (PQI) on the elemental rate processes of mesophase sphere formation from a coal tar pitch. An original coal tar pitch containing 3 wt.% PQI and a PQI free coal tar pitch derived from the original pitch were heated at 703 K for various periods of time. Time dependent changes in number/volume-based concentrations and radius distribution of mesophase spheres were quantified through microscopic observation and an image analysis. The quantified results were further analyzed by a kinetic model considering the three rate processes; generation, growth and coalescence of spheres. The model analysis revealed that PQI increases the total frequency of sphere generation by five times, decreases the rate constant of coalescence by an order of magnitude, and decreases the linear growth rate to less than half. It was also found that PQI delays the commencement of the sphere generation and expands the time period of the generation.