Thermal and co-pyrolysis of rubber seed cake with waste polystyrene for bio-oil production

Abstract

In this study, biofuels production through thermal and co-pyrolysis of rubber seed cake (RSC) with waste polystyrene (PS) using semi-batch reactor was investigated. Thermogravimetric analysis (TGA) of RSC at heating rate of 10 °C/min showed that R50 value as 1.87%/min at about 361.84 °C. Effects of pyrolysis temperature (350 °C – 600 °C) and heating rate (10 °C/min–40 °C/min) on product distribution (liquid, gas and bio-char) were considered. During thermal decomposition of RSC, the temperature significantly affected the yield and properties of the products. The maximum yield of RSC pyrolytic bio-oil (21.58 vol/wt%), gas (25.58 wt%) and, carbon-rich RSC bio-char (26.18 wt%) were obtained at 500 °C temperature for heating rate of 20 °C/min. Furthermore, the bio-oil yield and its energy content were enhanced from 21.58 vol/wt% to 48.7 vol/wt% and 32.25 MJ/kg to 37.48 MJ/kg through co-pyrolysis of RSC (50 wt%) with waste polystyrene (50 wt%). Value-added organic compounds such as phenolic, amide, creosol, esters, 1-dodecyne and styrene compounds were identified in bio-oil sample using gas chromatography with mass spectroscopy (GC–MS). In depth analysis of physico-chemical-thermal properties of RSC and obtained products (bio-oil and bio-char) using various analytical techniques suggested that RSC with WPS can be considered as a suitable feedstock for the production of value added chemicals including fuel.