## 3 Results and Discussion
### Ash Quality  
In Table 5, the composition of the ash produced, which was produced by the combustion of plastic waste and lignite, is presented (the values of the blended fuels were estimated theoretically). These values were derived from the EDS spectrums obtained during the observation of the ash samples with SEM. In Figure 5a,b, some SEM micrographs are presented suggestively, along with the areas used to obtain the EDS spectra. The evaluation of the ash quality can be facilitated by the ternary diagrams, in which the various oxides being present in ash are presented in three groups, namely, SiO\({}_{2}\) + Al\({}_{2}\)O\({}_{3}\) + Fe\({}_{2}\)O\({}_{3}\) + Na\({}_{2}\)O + TiO\({}_{2}\), CaO + MgO + MnO, and K\({}_{2}\)O + P\({}_{2}\)O\({}_{5}\) + SO\({}_{3}\). Depending on the relative contents of each group, the ash is characterized as type C (calcium type), S (silicon type), K (potassium type), and the intermediate type CK. Increased amounts of silicon and potassium are related to the potential formation of silicates and potassium salts, which are considered likely to cause deposits; thus, ash types S and K are considered ashes with high deposit risk. Type C is considered to be of low deposit risk since calcium salts typically exhibit higher melting points than potassium salts. Consequently, the intermediate type CK is considered medium-risk ash for deposition and slagging problems [39]. As can be seen in Figure 5c, lignite's ash, due to its high Ca content, is close to the C type but actually is marginally within the region of the CK type. The ash from plastic waste has lower Ca content but is also within the region of the CK type. Consequently, the ash quality of lignite and plastic waste is different, but it is of the same type, and thus similar medium slagging problems are expected. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Sample ID**} & **SiO\({}_{2}\)/MJ** & **Ash Production** & **\%Deviation of Sample** & **EFI\({}_{w}\)** & **\%Deviation of Sample** \\  & **from Production** & **Produced Ash from Lignite** & **Ash per Megaloue** & **Produced Ash per MJ from** \\  & **100,000 1 Fuel (t)** & **Combustion Ash (\%)** & **(kg/MJ)** & **Lignite Combustion Ash (\%)** \\ \hline PW & 74.5 & 5160 & \(-\)86.74 & 0.0015 & \(-\)95.04 \\ PW70 LIG30 & 74.8 & 14,580 & \(-\)62.52 & 0.0051 & \(-\)83.53 \\ PW50 LIG50 & 81.8 & 21,310 & \(-\)45.22 & 0.0091 & \(-\)70.33 \\ PW30 LIG70 & 89.2 & 28,510 & \(-\)26.71 & 0.0152 & \(-\)50.38 \\ LIGA \({}^{1}\) & 102.9 & 38,900 & 0.00 & 0.0307 & 0.00 \\ \hline \hline \end{tabular} \({}^{1}\) LIGA results were taken from a previous study by the authors [24]  
\end{table} 
Table 4: Maximum potential CO\({}_{2}\) emissions and environmental footprint indicator (EFI\({}_{w}\)) of single and blended fuels. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Sample ID**} & **SiO\({}_{2}\)** & **CaO** & **K\({}_{2}\)O** & **P\({}_{2}\)O\({}_{5}\)** & **Al\({}_{2}\)O\({}_{3}\)** & **MgO** & **Fe\({}_{2}\)O\({}_{3}\)** & **SO\({}_{3}\)** & **Na\({}_{2}\)O** & **TiO\({}_{2}\)** \\  & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** \\ \hline PW & 4.60 & 22.35 & 10.89 & 23.42 & 0.90 & 5.84 & 4.71 & 1.25 & 15.01 & 0.28 \\ PW70 LIG30 \({}^{1}\) & 9.37 & 26.81 & 11.70 & 17.42 & 1.54 & 9.33 & 3.30 & 1.62 & 10.51 & 0.19 \\ PW50 LIG50 \({}^{1}\) & 12.54 & 29.78 & 12.24 & 13.43 & 1.97 & 11.66 & 2.35 & 1.87 & 7.51 & 0.14 \\ PW30 LIG70 \({}^{1}\) & 15.72 & 32.75 & 12.78 & 9.43 & 2.39 & 13.99 & 1.41 & 2.12 & 4.50 & 0.08 \\ LIGA \({}^{2}\) & 20.49 & 37.20 & 13.60 & 3.44 & 3.03 & 17.48 & 0.00 & 2.50 & 0.00 & 0.00 \\ \hline \hline \end{tabular} \({}^{1}\) Chemical ash composition results of PW blends with lignite were calculated. \({}^{2}\) LIGA results were taken from a previous study [33].  
\end{table} 
Table 5: Results of chemical ash composition of the analyzed plastic waste sample and its blends with lignite.