The co-pyrolysis of lignocellulosic wastes with plastic has been found to improve the both the yield and quality of pyrolysis oil and gas products. In this study, the co-pyrolysis of corn stover (CS) with plastic (low-density polyethylene, and polypropylene) were studied through thermogravimetric analysis. The parameter “change in weight loss rate” denoted by ΔW was used to quantify the synergistic effects on the yield during co-pyrolysis. The ΔW values were fitted using a combined mixture design to generate an RSM model relating the factors mixture component proportions, plastic type, and temperature to the response Δ W. From numerical optimization, the obtained optimum co-pyrolysis conditions are: (a) 0.60 CS proportion, 0.40 LDPE proportion, and 481.73 ℃ temperature for CS-LDPE, (b) 0.68 CS proportion, 0.32 PP proportion, and 492.15 ℃ temperature for CS-PP. The activation energy, and preexponential factor of the reactions in the co-pyrolysis process were also obtained using direct solution method. The activation energy of the thermal decomposition of plastic was found to be lower in the co-pyrolysis of corn stover and plastic than in the pyrolysis of pure plastic.
Keywords co-pyrolysis, corn stover, plastic, optimization, combined mixture design, synergistic effect