Kinetics of polyethylene pyrolysis in the atmosphere of ethylene

Abstract

Polyethylene is widely used due to its excellent properties. However, the growing demand and higher production of polyethylene have also brought new types of hazards. It is essential to study the pyrolysis of polyethylene for the polyethylene process conditions and the prevention of polyethylene dust explosion. In this paper, the pyrolysis of linear low-density polyethylene (LLDPE) and high-density polyethylene (HDPE) under different heating rates in N2 and different ethylene concentration was studied by the TG-DSC method. The pyrolysis kinetics of polyethylene was analyzed by using Li Chung-Hsiung thermal analysis method, and the pyrolysis characteristic and reaction kinetics parameters of LLDPE and HDPE were found. The research results show that the increase in the heating rate is beneficial to polyethylene pyrolysis in nitrogen. The temperature at the highest rate increases linearly with the heating rate. The rise of ethylene concentration has some inhibitory effect on the pyrolysis reaction of polyethylene, and ethylene has a significant impact on the polyethylene pyrolysis rate. We also found the most suitable mechanism function of polyethylene pyrolysis from the 12 considered mechanism functions. HDPE pyrolysis stability is higher than LLDPE in nitrogen, while LLDPE pyrolysis stability is higher than HDPE in ethylene.