## 4 Conclusions  
In this study, the particle dispersal approach for the SCR-deNO\({}_{x}\) facility of a 1000 MW coal-fired power plant was investigated. Evaluation was made on the accumulation of different-sized particles via CFD simulation. It was revealed that for the classic \(\pi\)-type SCR-deNO\({}_{x}\) facilities, the particle  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Detection Spot** & **A** & **B** & **C** & **D** & **E** & **F** & **G** & **H** & **I** \\ \hline
1 & 2.22 & 2.75 & 2.29 & 1.95 & 2.31 & 2.09 & 2.08 & 2.15 & 2.15 \\
2 & 2.60 & 2.74 & 2.30 & 1.99 & 2.15 & 2.13 & 2.10 & 2.67 & 2.31 \\
3 & 2.34 & 2.92 & 2.26 & 2.10 & 2.22 & 2.23 & 2.06 & 2.26 & 2.18 \\
4 & 2.23 & 2.62 & 2.31 & 2.15 & 2.43 & 2.32 & 2.12 & 2.26 & 2.37 \\
5 & 2.55 & 2.65 & 2.19 & 2.14 & 2.37 & 2.38 & 2.15 & 2.24 & 2.36 \\
6 & 2.52 & 2.81 & 2.15 & 2.27 & 2.56 & 2.50 & 2.23 & 2.60 & 2.30 \\
7 & 2.79 & 2.68 & 2.11 & 2.16 & 2.49 & 2.42 & 2.29 & 2.34 & 2.34 \\
8 & 2.44 & 2.48 & 2.03 & 2.14 & 2.48 & 2.21 & 2.21 & 2.54 & 2.25 \\ \hline \hline \end{tabular}
\end{table}
Table 8: Measured values of air velocity for the FMT with the low deflector installation (unit: m/s).  
accumulation predominantly occurred on one side of the catalysts' entrance, which corresponds to the inner side of the wedge-shaped turning, and the ash particles larger than \(8.8\times 10^{-2}\) mm were mainly responsible for the accumulation. A triangular deflector was optimized numerically and used to reduce the particle accumulation. According to the simulation results, installing the triangular deflector at the high-speed area of the vertical duct may be an efficient way to disperse the particles with relatively large sizes and reduce the accumulation. Statistical indices showed that after installing the deflector, the RSDs of the large-sized and extra-large-sized particles decreased from 75.25% to 61.73% and from 117.29% to 66.12%, respectively. The corresponding maximum percentages of the accumulation decreased from 26.73% to 21.70% and from 39.84% to 20.59%, respectively. FMT was carried out to validate the simulation results. The dispersal effect and the optimal installing position of the triangular deflector on particles with relatively large sizes were validated. This paper provides comprehensive investigations on particle accumulation and is a supplementary work for the former studies. The numerical and experimental results presented in this study may provide a good reference on reducing the particle accumulation and are valuable for further study. The proposed optimized triangular deflector along with its installing position were proven to be effective and can be easily implemented on high-dust SCR-deNO\({}_{x}\) facilities.  
Conceptualization, H.Z.; Data curation, H.Z.; Formal analysis, H.Z.; Funding acquisition, J.Y.; Investigation, H.Z.; Methodology, H.Z. and J.Y.; Project administration, J.Y.; Resources, J.Y.; Supervision, J.Y.; Validation, H.Z. and J.W.; Writing--original draft, H.Z.; Writing--review and editing, J.Y.  
This research was funded by the National Natural Science Foundation of China, grant number 61533013 and the Natural Science Foundation of Shanghai, grant number 17 ZR1414200.  
The authors declare no conflict of interest.