Synergistic Effect on Low-Pressure Pyrolysis of Biomass-Plastic Mixture Asrepresentative of Tibetian Tourism Solid Waste

Abstract

Tibetan tourism solid waste (TSW) has attracted worldwide attention due to its increased production and the potential environmental risks associated with its improper disposal. According to a survey on TSW, catering industry is the main source of TSW, thus a mixture of starch and low-density polyethlyene (LDPE) was selected to simulate Tibetan TSW, and pyrolysis of single and mixed components has been performed in a vertical tube furnace with variable pressure. The effects of temperature (400-700 ℃)  and pressure (0.02-0.1 MPa) on the distribution of pyrolysis products and the composition of the gas and liquid phases were investigated. The results show that the simulated TSW pyrolysis has a synergistic effect, more obviously, promoting the production of C1-C3 hydrocarbons in the gas phase and inhibiting the production of oxygenated organic matter in the liquid phase. In addition, the properties of the simulated TSW pyrolysis process and the time evolution of various functional groups were studied by TG-FTIR, and it was observed that the simulated TSW pyrolysis followed two stages of degradation: biomass degradation from 250-370 °C and then plastic degradation from 420-510 °C. The activation energies and finger-front factors of the reactions during pyrolysis were determined using the Coats-Redfern method. Interestingly, the activation energy of thermal decomposition of biomass and plastics during simulated TSW pyrolysis was lower than that of the pure form. This study provides basic knowledge of thermochemical process in Tibet, thus paves a way for clean and efficient treatment of TSW.

Keywords: Tibet；tourism solid waste；pyrolysis；pressure；kinetics