Pyrolysis kinetic study on homogenized high-density polyethylene with wheat waste using thermogravimetric analysis (TGA)

In this paper, the potential of different ratios of homogenized biomass and plastic wastes blend were investigated. For plastic waste, high-density polyethylene (HDPE) and for biomass, wheat wastes from Iran were selected due to abundance availability of the wastes. Pyrolysis kinetic study were conducted in three different ratios of HDPE (25%, 50% and 75% HDPE) combined with the wheat sample. Parameters used in this study are: heating rate of 10°C/min, feedstock size less than 250μm, N2 gas as Gas 1 during pyrolysis, purified O2 as Gas 2 to complete the combustion and the mass of the blend was kept at 15mg. The activation energy obtained from the Thermogravimetric analysis (TGA) for HDPE:wheat blend of ratio 1:3, 2:2 and 3:1 were 47.3798 kJ/kmol, 39.2978 kJ/kmol and 33.7889 kJ/kmol, respectively for the first decomposition stage and for the second decomposition stage were 17.2758 kJ/kmol, 30.2114 kJ/kmol and 80.8258 kJ/kmol, respectively using the Coats Redfern method. Lower value of activation energy in wheat compare to HDPE reduced the activation energy of homogenized samples. The percentage of carbon in plastic is higher than biomass can affect the emission after combustion. On the other hand, the higher percentage of HDPE in ratio increased the calorific value which is an important matter for a fuel.