Co-pyrolysis of sugarcane bagasse and waste high-density polyethylene: Synergistic effect and product distributions

Abstract

Co-pyrolysis of sugarcane bagasse (SCB) with waste high-density polyethylene (HDPE) was performed in a fixed-bed reactor under different temperatures (400–700 °C) and blending ratios (0–100%). Product yields and chemical compositions were compared with those from the pyrolysis of individual components to ascertain the synergistic effect between SCB and HDPE. The synergistic effect of SCB and HDPE produced higher liquid yield than the theoretical value. The effect was strongest at 600 °C and 60:40 HDPE:SCB ratio, with the maximum difference of 6.02 wt%. The positive synergistic effects on the production of high-value organic compounds (alcohol, hydrocarbons, and aromatics) and inhibition of oxygenated compounds were most prominent at 600 °C and 40:60 HDPE:SCB ratio. SCB-derived hydroxyl radicals favored the secondary cracking of HDPE primary volatiles, thereby promoting the formation of aliphatic compounds with lower carbon numbers. Co-pyrolysis of SCB and HDPE also produced oil with higher carbon (34% higher) and hydrogen (47% higher) contents, and with lower oxygen content (70% lower) than those of SCB pyrolysis oil. It also achieved a high calorific value of 42.41 MJ/kg, which is comparable to those of commercial diesel fuels.