Thermal and clinker‐catalyzed pyrolyses of polystyrene waste using the Portland cement solid‐base catalyst

Abstract Polystyrene is a nondegradable lightweight foamy substance that easily blows from landfills into drains and waterways. This material creates litter and water pollution and harms the wildlife who mistakenly eat it. This study investigated a cost‐effective pyrolysis approach for catalytic conversion of waste polystyrene into useful oil and gas products. The Portland cement was used as a solid base to catalyze the pyrolysis reaction for improving the product yield, lowering the reaction temperature and shortening the reaction time. Optimum reaction conditions were investigated by varying the process temperature, process time, and amount of the catalyst. The catalytic conversion of polystyrene into oil was measured about 94.98% at 400°C. In noncatalytic conversion experiments, same conversion efficiency was achieved at 600°C, which is significantly higher than the catalytic conversion. Catalytic pyrolysis produced oil with major part of volatile fractions and 42.14% styrene. The thermal pyrolysis produced oil with high styrene content (63.17%). Overall, styrene content of oil product was lower than the reported values in the literature. The noncatalytic pyrolysis produced nonreactive gases toward the copper‐I solution while catalytic pyrolysis produced highly reactive gases. The presence of olefins and acetylene in gaseous form confirmed the presence of hydrogen in the product.