Temperature and time influence on the waste plastics pyrolysis in the fixed bed reactor

Pyrolysis as a technique of chemical recycling of plastic materials is causing an increasing level of interest as an environmentally and economically acceptable option for the processing of waste materials. Studies of these processes are carried out under different experimental conditions, in different types of reactors and with different raw materials, which makes the comparison of different processes and the direct application of process parameters quite complex. This paper presents the results of investigation of the influence of temperature in the range of 450°C to 525°C, on the yield of the process of pyrolysis of waste plastics mixture, composed of 45% polypropylene, 35% low density polyethylene and 25% high density polyethylene. Also, this paper presents results of the investigation of the effect of the reaction, atintervals of 30-90 [min], on the yield of pyrolysis of the mentioned waste plastics mixture. Research was conducted in a fixed bed pilot reactor, which was developed for this purpose. The results of the research show that at a temperature of 500°C, complete conversion of raw materials was achieved, for a period of 45 [min], with a maximum yield of the pyrolysis oil of 32.80%, yield of the gaseous products of 65.75% and the solid remains of 1.46%. Afurther increase of temperature increases the yield of gaseous products, at the expense of reducing the yield of pyrolysis oil. Obtained pyrolysis oil has a high calorific value of 45.96 [MJ/kg], and in this regard has potential applications as an alternative fuel