Pyrolysis characteristics of excavated waste and generation mechanism of gas products

Abstract

The mining of landfills provides an important opportunity for waste resource recovery, and the excavated waste with potential useable value has attracted widely attention. In this work, the pyrolysis technique was used to analyze the properties of excavated waste, including the thermal characteristics and kinetics analysis, the distribution of pyrolysis products and the composition of pyrolysis gas. The pyrolysis of excavated waste was performed in a lab-scale reactor in the temperature range of 500–900 °C. The results show that the pyrolysis activation energy of wood and textile was lower than that of plastics and rubber, and it was easier for the pyrolysis reaction to proceed. With the increase of temperature, the pyrolysis gas yield increased and the tar showed a decreasing trend. The plastic has the highest yield of tar with 74.9% and the textile has the highest yield of gas with 61.8% at 900 °C. Wood and rubber tend to produce high yield char with 28.5% and 40.6%, respectively. The pyrolysis gas composition was determined by Micro GC, and the release pattern during pyrolysis was also monitored. High temperature favors the production of H2/CO, and hinders the CO2/CH4. Plastics and rubber were more likely to produce C2∼C3 gases than wood and textiles. In addition, the pyrolysis properties of excavated waste and raw waste was compared.