## 4 Calculating the Fuel Efficiency Indicator Using the WSM and the WPM
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**Component** & **W\({}^{\mathbf{a}}\) (\%)** & **A\({}^{\mathbf{d}}\) (\%)** & **V\({}^{\mathbf{d}}\) (\%)** & **Q\({}^{\mathbf{a}}\) (MJ/kg)** & **C\({}^{\mathbf{d}}\) (\%)** & **H\({}^{\mathbf{d}}\) (\%)** & **N\({}^{\mathbf{d}}\) (\%)** & **S\({}^{\mathbf{d}}\) (\%)** & **O\({}^{\mathbf{d}}\) (\%)** \\ \hline Coal sludge & 18.8 & 16.4 & 20.80 & 21.61 & 88.27 & 4.35 & 2.18 & 0.57 & 4.63 \\ Filter cake & 43.5 & 37.0 & 41.47 & 19.24 & 73.27 & 4.90 & 1.02 & 0.22 & 20.59 \\ Coal & 10.1 & 8.5 & 40.19 & 24.82 & 77.46 & 6.25 & 2.27 & 0.35 & 13.67 \\ Peat & 9.9 & 22.8 & 74.80 & 11.79 & 52.06 & 6.31 & 3.58 & 0.20 & 37.85 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Waste turbine oil properties. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Indicators** & **China** & **Japan** & **Russia** \\ \hline Energy indicators & \multicolumn{3}{c}{Weight coefficients} \\ \hline Gas-phase ignition delay time & 0.0665 & 0.0665 & 0.0665 \\ Heterogeneous ignition delay time & 0.0665 & 0.0665 & 0.0665 \\ Combustion duration & 0.0665 & 0.0665 & 0.0665 \\ Calorific value & 0.0675 & 0.0675 & 0.0675 \\ Minimum ignition temperature & 0.0665 & 0.0665 & 0.0665 \\ Ash content & 0.0665 & 0.0665 & 0.0665 \\ \hline Environmental indicators & \multicolumn{3}{c}{} \\ \hline Sulfur oxide emissions & 0.12 & 0.100 & 0.05 \\ Nitrogen oxide emissions & 0.12 & 0.100 & 0.05 \\ \hline Economic indicators & \multicolumn{3}{c}{} \\ \hline Fuel cost & 0.06 & 0.030 & 0.1 \\ Transportation costs & 0.05 & 0.070 & 0.1 \\ Availability of fuel (its components) & 0.05 & 0.050 & 0.1 \\ \hline Safety indicators & \multicolumn{3}{c}{} \\ \hline Fire and explosion safety & 0.05 & 0.05 & 0.05 \\ Dusting & 0.025 & 0.025 & 0.025 \\ Convenience of storage and transportation & \multicolumn{3}{c}{} \\ \hline Social indicators & \multicolumn{3}{c}{} \\ \hline Conservation of energy resources & 0.05 & 0.075 & 0.05 \\ Conservation of land resources & 0.05 & 0.075 & 0.05 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Weight coefficients of parameters, used in the weighted sum method (WSM) and the weighted product method (WPM) calculations. \begin{table}
\begin{tabular}{c c} \hline \hline
**Number** & **Composition** \\ \hline
1 & 100\% filter cake (wet) \\
2 & 55\% coal, 45\% water \\
3 & 40\% filter cake (dry), 50\% water, 10\% waste turbine oil \\
4 & 20\% coal sludge, 30\% filter cake, 10\% peat, 40\% water \\
5 & 100\% coal \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Fuels under study. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Component** & **W\({}^{\mathbf{a}}\) (\%)** & **A\({}^{\mathbf{d}}\) (\%)** & **V\({}^{\mathbf{d}}\) (\%)** & **Q\({}^{\mathbf{a}}\) (MJ/kg)** & **C\({}^{\mathbf{d}}\) (\%)** & **H\({}^{\mathbf{d}}\) (\%)** & **N\({}^{\mathbf{d}}\) (\%)** & **S\({}^{\mathbf{d}}\) (\%)** & **O\({}^{\mathbf{d}}\) (\%)** \\ \hline Coal sludge & 18.8 & 16.4 & 20.80 & 21.61 & 88.27 & 4.35 & 2.18 & 0.57 & 4.63 \\ Filter cake & 43.5 & 37.0 & 41.47 & 19.24 & 73.27 & 4.90 & 1.02 & 0.22 & 20.59 \\ Coal & 10.1 & 8.5 & 40.19 & 24.82 & 77.46 & 6.25 & 2.27 & 0.35 & 13.67 \\ Peat & 9.9 & 22.8 & 74.80 & 11.79 & 52.06 & 6.31 & 3.58 & 0.20 & 37.85 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Properties of the solid fuel components. A detailed analysis of the properties of components and characteristics of the fuel ignition and combustion was not the main task of this research; therefore, the properties of the components were not studied separately. In the MCDA calculations, we took the values that were obtained experimentally using the techniques from [PERSON] and colleagues [12; 13]. Since many of the fuel ignition and combustion parameters depended on the temperature in the combustion chamber, it was reasonable to compare them at different temperatures (we chose the range from 700 to 900 \({}^{\circ}\)C).