Kinetics of generation and destruction of pyridine extractables in a rapidly pyrolysing bituminous coal

Abstract Time resolved kinetics of the generation and destruction of pyridine extractables within a Pittsburgh No. 8 seam bituminous coal was measured as a function of pyrolysis-time history. Tentative activation energies for the generation and destruction processes are 28.8 kcal mol −1 and 42.2 kcal mol −1 , respectively. Extractables are formed by pyrolytic bond breaking and depleted from the coal through tar evaporation or destroyed by coke formation. The development and disappearance of coal plasticity, as measured with a fast response plastometer, correlates well with the generation and removal of the pyridine extractables. Extractables molecular weight increased with heating time, implying that repolymerization reactions contribute to the coke formation.