Evaluation of The Efficiency of Selected Catalysts for The Pyrolysis of a Propane–Butane Fraction

This study evaluates the efficiency of selected catalysts for the pyrolysis of a propane–butane fraction under inert, oxygen-free conditions. Experiments were conducted in both pulse and flow reactors within a temperature range of 650–860 °C. Catalyst performance was assessed based on conversion and selectivity. In a quartz reactor, thermal cracking led to high yields of unsaturated hydrocarbons, especially ethylene and propylene, with ethylene selectivity reaching 55% at 730 °C. Flow reactors with Zn-, Cu-, Mn-, and Fe-based coatings showed that the Zn-coated system provided the highest olefin yield (62.2 wt.%) and minimal coke formation (0.24%). Activation energy analysis indicated that Zn required less energy (150–200 kJ/mol), supporting a radical reaction mechanism. The catalytic activity followed the order: Zn > Cu > Mn > Fe. The enhanced performance of Zn is attributed to its low oxidation state and hydrogenation capability, which suppresses coke formation. These results demonstrate the critical role of catalyst material and reaction environment in maximising olefin production during propane–butane pyrolysis.