Process and Kinetics of Pyrolysis of COPNA Resin Synthesized from FCC Slurry

The mechanism and kinetics of pyrolysis of condensed poly-nuclear aromatic (COPNA) resins were investigated by non-isothermal thermogravimetry/derivative thermogravimetry measurements at various heating rates (10, 20 and 30 K/min) in nitrogen atmosphere. The changes in the functional groups, microstructure, and elemental composition of COPNA resins heated to different temperatures (200, 400, and 600 ℃) were investigated by Fourier transform infrared spectroscopy, scanning electron microscopy, and elemental analysis, respectively. The results of the pyrolytic experiments indicated that the pyrolysis process could be divided into three stages: an initial weight loss stage ranging from 225—450 ℃,a second weight loss stage ranging from 450—560 ℃, and a thermally stable stage occurring above 560 ℃. The heating rate had little effect on the pyrolysis process, and thermogravimetric parameters of COPNA resin, such as temperature at initial weight loss stage (Ti), temperature at ?nal weight loss stage (Tf) and temperature at maximum weight loss stage (Tmax),shifted towards higher temperatures when the heating rate was increased. At higher heating temperature, the number of aliphatic chains and substituted groups attached to aromatic rings of the resultant sample was reduced, whereas the C/H ratio and porosity rate increased. Pyrolysis kinetics studies showed that the activation energy (E) range for the first and second weight loss stages was 150—210 kJ/mol and 210—275 kJ/mol, respectively, which showed that the mechanism of thermal decomposition differed from that of the weight loss stages. The k0 value was in the orders of between 1011/s and 1018/s when the activation energy was less than 250 kJ/mol. When the activation energiy was greater than 250 kJ/mol, there was a linearly increasing relationship between k0 and E.