# Management of Plastic Wastes through Recent Advanced Pyrolysis Processes
## 3 Recent Advances in Fuel Production from Plastic Pyrolysis
**Pyrolysis Box-Behnken Design:** Another study [49] proposed an optimization method for the pyrolysis process parameters using the Box-Behnken design (BBD) technique for the first time. Pyrolysis of polypropylene (PP) grocery bags was conducted using a semi-batch pyrolytic fixed-bed reactor to produce fuel oil. The effect of three major process parameters, namely temperature, nitrogen flow rate, and substrate feed rate, on fuel oil yield was investigated using the response surface methodology (RSM) with the BBD. A BBD-based 3\({}^{3}\) factor design was employed in this study; the values of the parameters tested were in the range of 400-550 \({}^{\circ}\)C, 5-20 mL min\({}^{-1}\) nitrogen flow rate, and 0.25-1.5 kg h\({}^{-1}\) feed rate, and their effects on the fuel oil yield were observed. The highest oil yield of 89.34% was obtained at 481 \({}^{\circ}\)C, 13 mL min\({}^{-1}\) nitrogen flow rate, and 0.61 kg h\({}^{-1}\) feed rate. The quadratic model obtained for the response was also very reliable, with R\({}^{2}\) = 0.99. The statistical test showed the strong influence of these process parameters on the yield of fuel oil. Moreover, the fuel oil was further analyzed to determine its properties. The oil consisted of high contents of carbon and hydrogen with a calorific value of 45.42 MJ kg\({}^{-1}\), resembling values of those of commercial petroleum fuels. The fuel oil had higher Research Octane Number (RON) and Motor Octane Number (MON) values than that of conventional gasoline, indicating better antiknock properties. A further analysis of the oil revealed that the oil contained around 30 compounds and was enriched with paraffin and olefins in the carbon range of C4-C20. This carbon range indicates the presence of diesel, kerosene, and gasoline in the fuel oil, which shows its potential as an alternative fuel for different industrial applications. **Pyrolysis-effect of condenser temperature. ** [PERSON] et al. [50] aimed to study the effect of condenser temperature on the quality of liquid oil obtained from the pyrolysis of plastic bags. The feedstock consisted of plastic bags collected from different stores in Kalasin province, Thailand. The pyrolysis process took place in a fixed-bed reactor at 300 \({}^{\circ}\)C, having two condensers, and the liquid oil was collected at both condensers. The second condenser is set at a temperature of \(-\)40 \({}^{\circ}\)C, while the first condenser's temperature was set at five different levels, which are 10, 20, 30, 40, and 50 \({}^{\circ}\)C. It was observed that increasing the temperature of the first condenser from 10 to 30 \({}^{\circ}\)C increased the yield of the first oil from 53.3 to 70.6%. However, when the temperature was further increased to 50 \({}^{\circ}\)C, the % yield dropped to 37.3%. Also, the yield of the second oil increased from 2.7 to 7.3% when the temperature was increased from 10 to 40 \({}^{\circ}\)C, but decreased at a temperature of 50 \({}^{\circ}\)C.  
Analyzing the first fuel showed that it exhibited the highest heating value (HHV) of 42.4 MJ/kg at 10 \({}^{\circ}\)C, while the lowest value of 37.1 MJ/kg was observed at 50 \({}^{\circ}\)C. Also, the composition of the first fuel was very similar to the chemical diesel. However, increasing the temperature of the first condenser from 10 to 50 \({}^{\circ}\)C decreased the density and calorific value of the first fuel. On the other side, analyzing the second fuel, it was found that increasing the temperature from 10 to 50 \({}^{\circ}\)C increased the HHV from 36.2 to 38.1 MJ/kg, but the highest HHV was still lower than that of the first fuel. However, increasing the temperature increased the density and calorific value of the second fuel. The second fuel composition consisted mainly of benzene, cyclononane, and toluene, giving it the physical appearance of gasoline. This study has demonstrated the potential use of plastic oils as alternative fuels for diesel and gasoline. **Pyrolysis with mixed-plastic wastes:** [PERSON] et al.