## 4 Results
### The Comparison of Results with Literature  
Table 4 shows the comparison of results for ammonia stripping system with the literature. First, the stripping column results according to pH were compared. In this study, the ammonia removal efficiency increased in proportion to ammonia fraction as the pH increased. [PERSON] et al. [15] reported that an increase in pH increase leads to improve ammonia stripping rate and mass transfer rate. When ammonia fraction and air supply are similar, the removal rate and mass transfer coefficients are also similar to those derived from literature [15].  
Secondly, packed tower results were compared. It is difficult to compare the mass transfer coefficient arithmetically because the interfacial area for the packed tower varies depending on the design of the tower and the packed material. However, it is possible to compare the approximate mass transfer rates by considering the ammonia fraction, air supply, and liquid ratio.  
[PERSON] et al. [14] derived the mass transfer coefficient according to air flow rate. Although there is no mention of the L/G ratio, it can be interpreted that the lower L/G, the higher \(K_{L,\ NH_{3}}a\), since the L/G decreases as the air flow rate increases. When compared with this study, it was confirmed that \(K_{L,\ NH_{3}}a\) was almost same under similar air supply conditions. It is considered that the calculated \(K_{L,\ NH_{3}}a\) values are within a reasonable range when compared with the reports by [PERSON] et al. [14] and [PERSON] et al. [12]. [PERSON] et al. [16] reported the highest value of \(K_{L,\ NH_{3}}a\) values under very low L/G ratio when compared to other literatures.  
In addition, ammonia removal rate was also compared for the jet loop reactor and the water-sparged aerospace. In these two reactors, as in the column and packed tower, the mass transfer coefficient increased as the liquid to gas ratio decreased.  
Figure 7: Ammonia removal rate according to the volume of air supplied at 70 \({}^{\circ}\)C, pH 8.5, and different L/G ratios.  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Equipment** & **T** & **PH** & \(f_{\text{NH}_{b}}\) & **Time** & **Air Supplied** & **LG \({}^{*}\)** & \(\eta\)** & \(K_{L,\text{NH}}\)\({}_{\blacksquare}\)** & **Ref.** \\  & & & **(b)** & **(a)** & **(a-Air/Liquid)** & **(a-Liquid/m\({}^{3}\)-Air)** & **(b)** & **(a)** & **Ref.** \\ \hline  & & 8.9 & 0.260 & & & & 13.9 & 0.219 & \\  & 20 & 9.4 & 0.527 & 2.5 & 2250 & - & 38.0 & 0.340 & This work \\ Stripping & & 10.2 & 0.875 & & & 624.4 & 0.462 & \\ column without & & 10.8 & 0.965 & & & 72.6 & 0.574 & \\ \cline{2-9} circulation & & 10 & 0.864 & & 1125 & & 24.8 & 0.084 & \\  & 25 & 12 & 0.998 & 3 & 1125 & - & 55.4 & 0.24 & \\  & & 12 & 0.998 & & 2250 & & 76.1 & 0.44 & \\ \hline  & & & 6 & 1572 & 4.5 & 57.1 & 0.194 & \\  & 70 & 8.5 & 0.761 & 6 & 262 & 26.8 & 63.0 & 0.222 & \\  & & & 12 & 262 & 53.6 & 77.3 & 0.174 & This work \\  & & & & 24 & 262 & 107.2 & 81.5 & 0.099 & \\ \cline{2-9} Packed tower & & & & & 720 & & 63.6 & 0.086 & \\ with circulation & 50 & 10 & 0.970 & 12 & 1440 & - & 83.4 & 0.166 & \\  & & & & 2880 & & 98.7 & 0.368 & \\ \cline{2-9}  & 25 & 11 & 0.985 & 24 & 4500 & 6.67 & 99 & 0.18 & [12] \\ \cline{2-9}  & 15 & 10.8 b & 0.937 b & 3.5 & 3000 & 0.332 & 75 & 0.42 & [16] \\ \hline Jet loop reactor & 20 & & & 7.8 & 930 & 2500 & 45.6 & 0.081 & \\  & & & & 7.8 & 1400 & 1667 & 87.2 & 0.299 & \\ \cline{2-9} Water-sparged & & & & 6.8 & 2030 & 1000 & 96.3 & 0.629 & \\ \cline{2-9} aerocyclone & 25 & 11.5 b & 0.995 & 3.5 & 1540 & 0.0032 & 98.9 & 0.78 & \\  & & & & & 2660 & 0.0018 & 93.7 & 1.32 & \\ \hline \hline \end{tabular} \({}^{*}\)Liquid to gas ratio, L/C \({}^{*}\)Average value.  
\end{table}
Table 4: The comparison of removal rate and overall volumetric mass transfer coefficient based on the liquid phase of ammonia.