## 3 Results and Discussion  
### Model Validation  
In this phase of simulation, the experimental data of the first minute reported by [PERSON] [19] is used. The tar model used in this study was a mixture of compounds benzene, toluene, and ethylbenzene with mass fractions: 50% benzene, 30% toluene, and 20% ethylbenzene. The mass fraction values of these materials were selected because they are almost the mass fraction values of the tar compounds collected and measured from a fluidized bed gasifier [42]. The studied solvent temperatures for this experiment are 30, 40, and 50 \({}^{\circ}\)C. The studied solvent flow rates are 53, 63 and 73 mL/min. The studied heights of the packed bed are 0.5, 0.8, and 1.1 m. The pressure of both solvent and gas stream is 20 psig. The simulation results are presented in terms of removal efficiencies of tar compounds and reported as a function of operating parameters, i.e., the solvent temperature, the solvent mass flow rate, and the packed bed height.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multicolumn{5}{c}{**MAPE at Flow Rates of 53 mL/min, and Bed Height of 0.5 m**} \\ \hline  & \multicolumn{2}{c}{**Benzene**} & \multicolumn{2}{c}{**Toluene**} & \multicolumn{2}{c}{**Ethylbenzene**} \\ \hline
**Temperatures \({}^{\circ}\)C** & **RB** & **EQ** & **RB** & **EQ** & **RB** & **EQ** \\ \hline
30 \({}^{\circ}\)C & 1.0\% & 6.7\% & 0.1\% & 4.2\% & 1.9\% & 1.9\% \\ \hline
40 \({}^{\circ}\)C & 2.4\% & 8.7\% & 0.1\% &  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multicolumn{5}{c}{**MAPE at Flow Rates of 53 mL/min, and a 0.5 Bed Height of 1.1 m**} \\ \hline \hline \multicolumn{5}{c}{**Benzene**} & \multicolumn{3}{c}{**Toluene**} & \multicolumn{3}{c}{**Ethylbenzene**} \\ \hline
**Temperatures \({}^{\circ}\)C** & **RB** & **EQ** & **RB** & **EQ** & **RB** & **EQ** \\ \hline
30 \({}^{\circ}\)C & 0.0\% & 1.0\% & 3.0\% & 3.2\% & 1.3\% & 1.4\% \\ \hline
40 \({}^{\circ}\)C & 1.4\% & 1.3\% & 3.3\% & 3.7\% & 1.5\% & 1.7\% \\ \hline
50 \({}^{\circ}\)C & 5.5\% & 2.6\% & 5.1\% & 6.0\% & 4.2\% & 4.6\% \\ \hline \multicolumn{5}{c}{MAPE at flow rates of 63 mL/min, and bed height of 1.1 m} \\ \hline Temperatures \({}^{\circ}\)C & RB & EQ & RB & EQ & RB & EQ \\ \hline
30 \({}^{\circ}\)C & 0.7\% & 1.1\% & 3.4\% & 3.5\% & 2.1\% & 2.1\% \\ \hline
40 \({}^{\circ}\)C & 1.8\% & 3.2\% & 4.7\% & 4.9\% & 2.7\% & 2.9\% \\ \hline
50 \({}^{\circ}\)CFigure 8: Effect of solvent temperature on the removal efficiency of tar components at a bed height of 0.8 m and different solvent volumetric flow rates 53 mL/min (**above**), 63 mL/min (**middle**), 73 mL/min (**below**).  
Figure 9: Effect of solvent temperature on the removal efficiency of tar components at a bed height of 1.1 m and different solvent volumetric flow rates of 53 mL/min (**above**), 63 mL/min (**middle**), 73 mL/min (**below**).  
The deviation of results between the equilibrium model and the experimental data is because the equilibrium model assumes that the vapor and liquid left on the plates are in thermodynamic equilibrium [19]. In actual operation, the equilibrium between the gas and liquid phases is rare [29]. Although the rate-based model shows a good agreement with experimental data, there is a deviation. It may be explained because of the rate-based model based on the empirical correlations used for calculating the mass and heat transfer parameters [26]. It is clear that the deviation of results between the rate-based model and the experimental data increased by increasing the bed height. The explanation for this trend is that by increasing the packing bed height, the conditions will be close to the equilibrium state; this explains why the excellent agreement between the rate-based model and the equilibrium model increased by increasing the bed height. As a whole, the simulation results predicted by rate-based model are in the range of the experimental results.