## 4 Results and Discussion
### Reactor Simulation and Analysis of the Effect of the Feed Oil Changes on the System
A variation of 10.90% in the mass fraction of methyl esters was observed during the change from palm to mustard oil. Moreover, a variation up to 22.07% was presented in the change from mustard to sunflower oil. Finally, the mass fraction had a difference of 9% between steady states after the final change from sunflower to palm oil (see Table 4). Although the mixture temperature is also disturbed after each feed oil change, its variations are not significant, in contrast to what was previously observed for ester mass fraction. This is because the enthalpy of the reactions for different oils are practically identical. Although the temperature also depends on reaction rates (see Equation (24)), the differences between oils seem not to have an important influence on the temperature. The magnitude of temperature variations, in the worst-case scenario, was only 1.48%. Table 4 summarizes the results of the operational disturbances in the reactor  
Figure 4: Concentration of methyl esters after changes with different types of feed oil: (**a**) palm to mustard; (**b**) mustard to sunflower; and (**c**) sunflower to palm. Figure 6 shows the dynamics of triglyceride concentration, including those forming in the cross-linking reaction, during the transition from palm and mustard oil after the feed oil change at minute 500. The concentrations of these types of triglycerides are lower than the concentrations of triglycerides characteristic of pure oils. The low formation of triglycerides in cross-linking reaction is due to kinetic forward reactions being similar to the kinetic of reward reaction in the usual transesterification, which are lower. Similarly, small concentrations of triglycerides and diglycerides are produced in all cross-linking reactions, which only affect reactor dynamics during the transitory period, which is relatively short compared to the reactor operation time. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \multirow{2}{*}{**Variable**} & \multirow{2}{*}{**Change**} & \multicolumn{2}{c}{**Transitory State**} & \multicolumn{2}{c}{**Staady State**} & \multicolumn{2}{c}{\(\Delta var\)} \\ \cline{3-8}  & & **Duration** & **Min. Value** & **Before** & **After** & **Value** & **Percentage** \\ \cline{3-8}  & & **(min)** & **(\% g/g)** & **(\% g/g)** & **(\% g/g)** & **(\% g/g)** & **(\% g/g)** & **Percentage** \\ \hline \multirow{3}{*}{\(X_{\varepsilon}\)} & P-M & 19.14 & 46.96 & 62.40 & 55.56 & \(-\)6.84 & \(-\)10.90 \\ \cline{2-8}  & M-G & 10.00 & 52.31 & 55.6 & 67.87 & 12.27 & 22.07 \\ \cline{2-8}  & G-P & 21.27 & 33.94 & 67.87 & 62.40 & \(-\)5.62 & \(-\)9.00 \\ \hline \multirow{3}{*}{\(T\)} & P-M & 5.72 & NA & 60.17 & 59.28 & \(-\)0.89 & \(-\)1.48 \\ \cline{2-8}  & M-G & 16.10 & NA & 59.28 & 59.85 & 0.57 & 0.95 \\ \cline{1-1} \cline{2-8}  & G-P & 22.60 & 59.24 & 59.85 & 60.17 & 0.32 & 0.53 \\ \hline \end{tabular}
\end{table} 
Table 4: Disturbance effects of oil change in the reactor. Figure 5: Effect of the oil changes in the mass fraction of esters. Figure 6: Triglycerides from palm oil, mustard oil, and formed in the cross-linking reactions after the change from palm to mustard oil.