# Recent Advancements in Anaerobic Digestion and Gasification Technology
## 10 Feedback for Gasification Technology  
Biomass gasification entails the use of various types of feedstocks, which include but are not limited to, woody biomass (chips, wood pellet, sawdust, and tree bunches); agricultural and food biomass (rapeseed, jatropha, miscanthus, sugar cane bagasse, nutshell, rice husk, wheat straw, and oil production waste); and industrial and animal biomass [64]. Before gasification, feedstocks are characterized to determine their suitability; Table 7 presents the characterization of some selected feedstocks for gasification.  
For a successful study of the gasification process, the feedstock and its properties are necessary for syngas production [90]. These properties (moisture content, heating value, content of ash, alkali metals, and lignin ratio) are briefly discussed, as they affect the composition and yield of the syngas [91; 92]. A study conducted by [PERSON] et al. [34]  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & & & & & \\ \hline \multirow{2}{*}{**Types of Feedstocks**} & \multirow{2}{*}{\begin{tabular}{c} **Moisture Content** \\ **(wt\%)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Volatile Matter** \\ **Content (wt\%)** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **Ash Content** \\ **(wt\%)** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Heat of Combustion** \\ **(MJ/kg)** \\ \end{tabular} } & \multirow{2}{*}{**References**} \\ \hline Wood pellet & 6.7 & 84.3 & 0.8 & 20.8 & [78] \\ \hline Saw dust & 7.4 & - & 0.6 & - & [79] \\ \hline Chips (pine wood) & 4.5 & 78.4 & 2.6 & 16.1 & [80] \\ \hline Root of mango tree & \multirow{2}{*}{5.73} & \multirow{2}{*}{67.87} & \multirow{2}{*}{3.91} & \multirow{2}{*}{18.52} & [81] \\ \cline{1-1} \cline{5-5} (tree bunches) & & & & & \\ \hline Eucalyptus prophyll & 11.37 & 75.34 & 0.27 & 17.16 & [82] \\ \hline \multicolumn{5}{c}{**Agricultural and Food Biomass**} \\ \hline Miscanthus & 10.67 & 65.65 & 5.34 & 17.00 & [81] \\ \hline Oil production waste & 5.9 & 80.1 & 7.6 & 20.1 & [78] \\ \hline Sugar cane bagasse & - & 87.4 & 2.9 & - & [83] \\ \hline Wheat straw & 2.50–7.00 & 60.0–75.0 & 5.64–15.0 & 16.12 \(\pm\) 0.19 & [78; 84; 85] \\ \hline Rice husk & 8.02 & 61.43 & 18.02 & - & [84] \\ \hline Pea nutshell & - & 84.1 & 1.4 & - & [83] \\ \hline Cocoa nutshell & 7.16 & 68.58 & 2.26 & - & [84] \\ \hline Jatropha seed cake & - & 73.5 & 7.3 & - & [83] \\ \hline \multicolumn{5}{c}{**Animal and Industrial Biomass**} \\ \hline Microalgae & 3.0–10.0 & 70–81 & 5.0–10.0 & 20.0–25.0 & [86; 87] \\ \hline Brewer’s spent grain & 3.97 & 83.3 & 3.22 & 21.6 & [88] \\ \hline Spent coffee grounds & 2.66 & 80.44 & 1.25 & - & [85] \\ \hline Natural rubber & 1.71 & 89.98 & 3.60 & 45 & [89] \\ \hline \hline \end{tabular}
\end{table}
Table 7: Characteristics of feedstock for gasification.  
revealed that feedstock with a high composition of cellulose and hemicellulose resulted in the production of syngas with a higher concentration of carbon monoxide and methane, whereas feedstock with a high composition of lignin generated syngas with a higher concentration of hydrogen.  
Having provided the summary of the properties of some selected feedstock for gasification in Table 7, it is important to state the optimum ranges for these feedstocks according to their classifications. Hence, Table 8 presents the summary of the recommended operating parameter of biomass waste from the literature.