Figure 3 shows the viscosity of the 10% polymer fuels produced from various plastics. The results show that the viscosities of the PE and PP polymer fuels decrease with increasing temperature. The viscosity of the PS fuel decreases at temperatures below 150 ℃ because segregation and sedimentation of PS occurs.
Figure 4 shows the effect of the weight-average molecular weight of the plastics on the viscosity of the polymer fuels at 120 ℃. These results show that viscosity increases in proportion with the weight-average molecular weight of the plastics used to make the fuel. Figure 5 shows the viscosity of the fuels made from PE2, PP1 and PP2. From the results, it is obvious that the higher plastic contents produce fuels of higher viscosity. The engine used in the tests is a light-duty, high speed, direct injection diesel engine that is very sensitive to fuel viscosity and for which the maximum allowable fuel temperature is 150 ℃, as mentioned above. Thus, it is suggested that 5% PE2, 25% PP1 and 5% PP2 polymer fuels may be appropriate for use in the present diesel engine system. In a practical system, a large heavy-duty diesel engine may allow the use of viscous fuels of viscosities around 100 cSt and for which the maximum fuel temperature is around 300 ℃. In such circumstances, 10% PE2, 40% PP1 and 10% PP2 fuels are applicable.
The density of the polymer fuel as a function of temperature was also measured. The results reveal that the density of these polymer fuels is almost the same as that of heavy oil A at the temperatures tested, as shown in Fig. 6.
Fig. 3 The viscosity of the 10% polymer fuels
Fig. 4 The effect of Mw of the plastics on the viscosity of the polymer fuels
3.2 Thermal Properties of the Polymer Fuels
Both TGA and DTA were conducted in order to investigate the distillation characteristics and thermal properties of the new polymer fuels. TGA is used to determine the mass ratio of the sample, and DTA demonstrates the heat release characteristics of the sample. Maximum temperature was set at 500 ℃, and testing was conducted while increasing the temperature at 25 ℃/min in an atmosphere of air.
Fig. 7 The results of TGA and DTA for heavy oil A
