Pyrolysis of polypropylene over a LZ-Y52 molecular sieve: kinetics and the product distribution

Abstract

The present work demonstrates the decomposition kinetics of polypropylene in the presence of LZ-Y52 molecular sieve. The pyrolysis was performed at different heating rates in the temperature range 30–600 °C in an inert atmosphere. The kinetics parameters were calculated by applying Ozawa–Flynn–Waal, Tang–Wanjun, and Coats–Redfern (modified) methods. The activation energy (Ea) and frequency factor (A) were found in the range of 52.44–74.50 kJ mol−1 and 1.5 × 10−2 to 9.05 × 108 min−1, respectively. Based on the activation energy data, all three methods agreed well. Moreover, pyrolysis was performed at 350–390 °C in a pyrolysis chamber and the conditions were optimized for maximum oil production. A 10% catalyst amount, at 370 °C, nitrogen flow rate 16 mL/min, and reaction time 60 min were the optimum conditions during experimental work. The products collected were analyzed by gas chromatography/mass spectrometry. In the case of thermal degradation, no oil was obtained; however, thermo-catalytic degradation resulted in more than 40% oil at 370 °C for 1 h. Fuel properties of the oil obtained were determined. These properties were in good agreement with standard values and therefore it has potential applications for replacing fuel oil.