Catalytic pyrolysis of plastic wastes for liquid oils' production using ZAP USY zeolite as a catalyst

The use of plastic is increasing every year and is a major environmental problem. A possible solution to reduce plastic pollution is to convert it into synthetic fuel, which can be achieved by a pyrolysis process. The catalyst used can influence the quality of the pyrolysis products. In the present work, we tested the influence of ZAP USY zeolite on the quality and quantity of pyrolysis oils produced from high-density polyethylene, low-density polyethylene, polypropylene, and polystyrene plastic from municipal waste. The pyrolysis process was carried out in a laboratory-scale single batch fixed bed pyrolysis reactor at the temperature of about 400 degrees C +/- 30 degrees C. The mass ratio of plastic and catalyst was 10:1. The obtained results show that the use of a catalyst reduces the pyrolysis oil production and solid residues' formation. The use of a catalyst also decreases the calorific value, density, surface tension, and kinematic viscosity of the obtained oils slightly. The use of a catalyst increases the plastic degradation rate, which is evident from the result of the carbon number distribution. The pyrolysis oils obtained by catalytic pyrolysis contain a higher amount of shorter chain molecules than oils obtained by thermal pyrolysis of waste plastic. The obtained results of the analyzed pyrolysis oils indicate that they have a high potential for possible use in internal combustion engines as an additive to conventional fuels, or as their substitute.

Automated summary

The use of plastic is increasing and causing environmental problems. Converting plastic into synthetic fuel via pyrolysis can help reduce plastic pollution. This study investigated the influence of a zeolite catalyst on the quality and quantity of pyrolysis oils from different types of plastic. The results showed that the catalyst decreased oil production and solid residues formation, and slightly affected the properties of the oils. Catalytic pyrolysis resulted in oils with shorter chain molecules and high potential for use as fuel additives or substitutes.