## 3 Results and Discussion  
### Coal and Biomass Sample Properties  
The proximate analysis, calorific value, and ultimate analysis of 20 types of coal (Nos. 1-20) used in this study are provided in Table 1. Among the coal samples, three types were American coals, two were Russian, two were Indonesian, two were Colombian, four were South African, and seven were Australian.  
The FR (fixed carbon (FC)/volatile matter (VM)) calculation is provided in Table 1, and the Van Krevelen plot considering the atomic ratio is provided in Figure 2. All samples used were bituminous or subbituminous. The nitrogen content was analyzed to range from 0.99% to 2.36%. The coal's heating values were between 6200 and 7150 kcal/kg. Three types of American coals exhibited a high moisture and oxygen content but a low sulfur content in the element analysis. Two types of Russian coals show different properties. Glencore had a high moisture and oxygen content whereas, Tugnuisky had high ash content. Indonesian coals exhibited typical characteristics of low-quality coals that have high water and oxygen content. Colombian coals exhibited the highest heat values, according to the higher heating value (HHV) standard, and the Australian coals (except for the NCA coal) exhibited the highest water content. The heating value was also high based on the HHV standard, but the overall ash contents were low. Four types of South Africa coals had very little moisture content compared to the others but had a high ash content overall. However, the fixed carbon content was very high, as was the FR.  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**No.**} & \multirow{2}{*}{**Sample**} & \multirow{2}{*}{**Country**} & \multicolumn{4}{c}{**Prosimate Analysis**} & \multicolumn{4}{c}{**Calorific**} & \multirow{2}{*}{**Ultimate Analysis (daf basis, wt \%)**} & \multirow{2}{*}{
\begin{tabular}{c} **Atomic** \\ **Ratio (\(\star\))** \\ \end{tabular} } \\  & & & & **f**e** & & **A**h** & & **HHV** & **LHV** & **C** & **H** & **O** & **N** & **S** & **H/C** & **Q/C** \\ \hline \multirow{2}{*}{1} & Anglo & South Africa & 4.71 & 24.72 & 54.75 & 15.82 & 2.21 & 6651 & 638 & 82.37 & 45.45 & 1096 & 1.56 & 0.66 & 0.65 & 0.2 \\  & 2 & Clermont & Australia & 2.73 & 27.51 & 58.84 & 10.92 & 2.14 & 7090 & 6623 & 86.4 & 6.82 & 4.35 & 1.85 & 0.59 & 0.95 & 0.08 \\  & 3 & Cloud peak & USA & 19.73 & 36.8 & 39.25 & 4.22 & 1.07 & 6954 & 582 & 76.96 & 5.18 & 15.38 & 2.03 & 0.45 & 0.81 & 0.3 \\  & 4 & Flame & Australia & 1.98 & 28.81 & 48.27 & 20.94 & 1.68 & 6188 & 6065 & 872.8 & 5.4 & 4.5 & 2.05 & 0.81 & 0.74 & 0.08 \\  & 5 & Glencore & Russia & 12.37 & 34.11 & 45.59 & 7.93 & 1.34 & 6813 & 5970 & 77.19 & 5.11 & 5.16 & 2.17 & 0.38 & 0.79 & 0.29 \\  & 6 & Indomico & Indonesia & 14.29 & 38.64 & 39.31 & 7.76 & 1.02 & 6755 & 5790 & 75.45 & 5.37 & 15.9 & 1.78 & 1.51 & 0.85 & 0.32 \\  & 7 & Larans & Indonesia & 16.95 & 36.74 & 38.45 & 7.86 & 1.05 & 6498 & 5397 & 7412 & 5.31 & 1835 & 0.99 & 1.23 & 0.86 & 0.37 \\  & 8 & Light House & USA & 18.35 & 34.24 & 42.11 & 5.3 & 1.23 & 6920 & 5650 & 74.5 & 5.37 & 17.99 & 1.45 & 0.55 & 0.85 & 0.36 \\  & 9 & Light House & USA & 6.33 & 35.72 & 47.33 & 10.62 & 1.33 & 6966 & 5788 & 75.37 & 5.07 & 17.99 & 1.14 & 0.42 & 0.81 & 0.36 \\  & 10 & Macquarie & Colombia & 9.18 & 35.14 & 47.62 & 80.6 & 1.36 & 7029 & 6384 & 78.47 & 5.27 & 140.9 & 1.57 & 0.6 & 0.81 & 0.27 \\  & 11 & Mercurati & South Africa & 4.2 & 25.45 & 53.67 & 16.68 & 2.11 & 6461 & 6190 & 81.85 & 4.67 & 10.85 & 1.93 & 0.7 & 0.68 & 0.2 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Proximate analysis, calorific value, and ultimate analysis of coal samples.  
Figure 2: Van Krevelen plot of the samples.