Numerical and Experimental Investigations on Reducing Particle Accumulation for SCR-deNO\({}_{x}\) Facilities  
Haojun [PERSON]  
1 Department of Automation, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China; [EMAIL_ADDRESS] (H.Z.); jewang@sjtu.  
Although soot blowers are used before the catalyst layers [13; 19; 20], the blockage and erosion of the monolith catalysts often occur. Figure 1a shows the breakage of the catalyst layer for a 660 MW coal-fired power plant. Moreover, the high-speed flue gas containing ash particles would lead to severe erosion on the ammonia injection grid (AIG) and the support structure, as shown in Figure 1b. It would shorten the lifetime of the catalysts and threaten the performance of the SCR-deNO\({}_{x}\) facility. Hence, it is necessary to investigate the distribution of ash particles and take steps to disperse particle accumulation inside the SCR-deNO\({}_{x}\) facility.  
Recently, with the assistance of computational fluid dynamics (CFD), studies have been made upon particle behaviors inside the SCR-deNO\({}_{x}\) facilities [21; 22; 23]. [PERSON] et al. [24] numerically analyzed the catalyst breakage failure and presented the particle distributions at the entrance of the catalyst layers under different baffles configurations. [PERSON] et al. [25] experimentally and numerically studied the catalyst erosion of the SCR-deNO\({}_{x}\) reactor for a 660 MW coal-fired power plant. An integrated approach was proposed to predict the erosion condition and implement erosion optimization. [PERSON] et al. [26] presented a detailed investigation of particle deposition in monolith SCR-deNO\({}_{x}\) catalysts. The effects of particle diameter, particle density, gas velocity, turbulent intensity, chemical reaction and channel size were studied. Pilot-scale experiments on particle deposition of SCR-deNO\({}_{x}\) catalysts were carried out by [PERSON] et al. [27] and a model was developed, revealing the dominating mechanisms for particle deposition. Nevertheless, few research papers focus on the particle accumulation inside the duct and the corresponding solutions.  
In the present study, CFD simulations are carried out for the SCR-deNO\({}_{x}\) facility of a 1000 MW coal-fired power plant. Particle accumulation inside the duct is investigated with different particle sizes. A triangular deflector is proposed to disperse the particles with relatively large sizes and reduce accumulation. Optimal design is implemented on the structural parameters of the triangular deflector, including the angle against the wind and the height. Furthermore, the installing position of the triangular deflector in the vertical duct is assessed and optimized. The corresponding flow model test (FMT) is conducted with the optimized deflector as a validation of the dispersal effect and the optimal  
Figure 1: The damage caused by ash particles: (**a**) the breakage of the catalyst layer for a 660 MW coal-fired power plant, (**b**) the erosion of the ammonia injection grid (AIG) and the support structure.  
installing position. The installation of the triangular deflector is proven to be an efficient approach to reduce the particle accumulation, and can be applicable to high-dust SCR-deNO\({}_{x}\) facilities.