## 4 Conclusions  
Biomass torrefaction is presented as a process capable of improving the properties and combustibility of biomass. However, it is a technology that has not yet been able to prove its concept and definitively prove its potential. The lack of knowledge about the process and the technologies and its operation caused a delay in the implementation of torrefaction as a technology capable of improving the properties of biomass and making it an alternative to fossil fuels, mainly coal. The realization of studies like the one presented here becomes even more important, because there are no other similar reports which help the industrial sector of torrefied biomass to take the necessary steps for large-scale industrialization through the sharing of experiences and solutions, as this is the only way to create a true market for torrefied biomass. As regards expanding the size of a torrefaction unit, raising the scale from the laboratory to pilot dimension or from pilot to industrial dimension, further studies are needed, mainly in terms of knowledge of the kinetics of the reactions that occur during the process. This information is essential to help in the design of a larger-scale production unit as it is based on this knowledge of the reaction kinetics that the behavior of certain constituents of biomass can be defined, and based on these, to identify some important parameters, such as the residence time and operating temperature required to obtain a product with specific characteristics. Although most of the main problems related to the technical operation of a production unit have been largely corrected, there is still a lot of research work on the different forms of biomass and the model of how they react to the torrefaction process. At the same time, it is also necessary to understand how torrefaction can be integrated into other pre-processing and biomass-processing systems, namely gasification. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multicolumn{1}{c}{**Properties**} & **Units** & **Values** & **Test Reference** \\ \hline \multirow{4}{*}{**Thermogravimetric**} & Moisture & \% & 10–25 & EN14774-2 \\  & Volatiles & \% & 60–70 & EN15148 \\  & Fixed Carbon & \% & 16–20 & — \\  & Ashes & \% & \textless{}2 & EN14775 \\  & C & \% & 50–56 & EN15104 \\  & H & \% & 4–6 & EN15104 \\  & O & \% & 36–38 & EN15104 \\
**Elemental Analysis (db)** & N & \% & \textless{}0.500 & EN15104 \\  & S & \% & \textless{}0.03 & EN15289 \\  & Cl & \% & \textless{}0.02 & EN15289 \\
**Heating Value** & HHV (ar) & M]/kg & 18–19 & EN14918 \\  & LHV (ar) & M]/kg & 16–17 & EN14918 \\
**Bulk Density** & \multicolumn{2}{c}{kg/m\({}^{3}\)} & 250–350 & EN15103 \\  & As & mg/kg & \textless{}1 & EN15297 \\  & Cd & mg/kg & \textless{}0.5 & EN15297 \\  & Cu & mg/kg & \textless{}10 & EN15297 \\  & Pb & mg/kg & \textless{}10 & EN15297 \\  & Mg & mg/kg & 2000 & EN15297 \\  & Ni & mg/kg & \textless{}10 & EN15297 \\  & Zn & mg/kg & \textless{}100 & EN15297 \\
**Ashes** & \multicolumn{2}{c}{Shrinking T.} & \({}^{\circ}\)C & 1100 & CEN/TS15370-1 \\
**Fusibility—Oxidizing** & \multicolumn{2}{c}{Softening T.} & \({}^{\circ}\)C & 1200 & CEN/TS155370-1 \\
**Atmosphere** & \multicolumn{2}{c}{Hemispherical T.} & \({}^{\circ}\)C & 1200 & CEN/TS15370-1 \\  & Fluid T. & \({}^{\circ}\)C & 1200 & CEN/TS15370-1 \\  & Shrinking T. & \({}^{\circ}\)C & 800 & CEN/TS15370-1 \\
**Ashes** & \multicolumn{2}{c}{Softening T.} & \({}^{\circ}\)C & 1200 & CEN/TS15370-1 \\
**Fusibility—Reducing** & \multicolumn{2}{c}{Hemispherical T.} & \({}^{\circ}\)C & 1200 & CEN/TS15370-1 \\
**Atmosphere** & \multicolumn{2}{c}{Fluid T.} & \({}^{\circ}\)C & 1200 & CEN/TS15370-1 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Summary of the results obtained for raw materials used during the different phases of tests carried out between 2013 and 2016. Raw material was exclusively maritime pine woodchips. **Author Contributions:** Conceptualization, L.J.R.N. ; methodology, L.J.R.N. ; validation, L.J.R.N. ; formal analysis, L.J.R.N. ; investigation, L.J.R.N. ; resources, L.J.R.N.