Effects of Operating Factors on the Bio-Oil Produced from Pyrolysis of Plastic Wastes using Response Surface Methodology

This paper presents the influence of four operating factors (plastic type i.e feedstock, temperature, heating rate and the reaction time) on the bio-oil yield obtainable from pyrolysis of plastics wastes. To achieve this, twenty-seven (27) different experiments conducted on the pyrolysis of various plastic types under different pyrolytic operating conditions were sourced from different literature and then modelled using response surface methodology (RSM). This is to facilitate the establishment of regression relationship between the operating factors and the probable bio-oil yield from plastic waste making it possible to determine the impact of the operating factors. Some of the key results show that the regression model derived from the RSM could effectively model and predict the bio oil yield using the four operating factors with the R–square and the adjusted R–square value of 92.2% and 83.2%, respectively. It is also revealed that the different interactions among the factors result into different bio-oil production, hence, the need for determining the best interaction among the influencing factors for maximum bio-oil production. It can be generally observed from the results that temperature and plastic type (feedstock) have very strong effect on pyrolysis process of bio-oil production. Too high or too low temperature as well as the type of plastic used as feedstock could cause a very high variation in the bio-oil yield. The effect of reaction time is seen to be minimal as it is nearly constant for all the investigated scenarios.