Study of co-pyrolysis endpoint and product conversion of plastic and biomass using microwave thermogravimetric technology

Abstract

The purpose of this article is to explore possible ways to achieve synergistic optimization of bio-oil yield and energy recovery efficiency through microwave co-pyrolysis of biomass and plastics. The mechanism of co-pyrolysis was explored via an emerging microwave thermogravimetric technology of pyrolysis endpoint and product. The results showed that the microwave co-pyrolysis of plastic and biomass shortened the reaction time and increased the bio-oil yield. Furthermore, the bio-oil oxygen content reduced and the formation of high-calorific components (gasoline and diesel components) was directionally improved. Owing to the decrease in oxygen content and the rise in aliphatic hydrocarbons, the chemical energy of the bio-oil increased from 1.76 MJ/kg (plastic mixing ratio: 0%) to 6.40 MJ/kg (50%). The energy recovery efficiency of the microwave co-pyrolysis of the cow dung with 50% low-density polyethylene (LDPE) was over three times that of the pyrolysis of cow dung. The feasibility of microwave co-pyrolysis in improving bio-oil yield and energy recovery efficiency were proved, however, higher cost is still one of the reasons hindering the widespread application of this technology. This work provides theoretical possibilities for the recycling of biomass with low energy consumption.