Thermochemical behaviors, kinetics and bio-oils investigation during co-pyrolysis of biomass components and polyethylene based on simplex-lattice mixture design

Abstract Co-pyrolysis of biomass components (cellulose, xylan and lignin) and polyethylene (PE) was performed based on simplex-lattice mixture design, and the thermal decomposition behaviors, kinetics, and bio-oil compositions were investigated. The results showed that PE could promote the reduction of residual chars for co-pyrolysis of single biomass component and PE, and the variation of blending ratios resulted in the different interactions for co-pyrolysis of two biomass components and PE. When PE ratio was low, co-pyrolysis of any two biomass components could reduce the reaction order, and only in the presence of lignin, the interaction between cellulose and PE was significant in case of reaction order. The interactions between any biomass component and PE were all significant in affecting activation energy. In terms of reducing reaction activation energy, the interaction induced by xylan was stronger than that induced by lignin, and the synergy of cellulose was the weakest. The integration of organic products between cellulose and PE and between xylan and PE was limited, but obvious integration of lignin and PE -derived products was observed. During co-pyrolysis, lignin intermediates could be quenched to stable products, attributing to the effective hydrogen transfer and interactions between PE-derived radicals and lignin intermediates.