基于动态导流板的煤电锅炉脱硝流场优化研究OA

[Objective]The flow field uniformity of the denitration system of coal-fired units has an important influence on the denitration efficiency.In order to improve the problem of uneven distribution of flow field in flue gas denitrification system of large coal-fired power units,it is necessary to optimize the flow field of denitrification flue.[Methods]In this paper,a dynamic guide vane structure optimization scheme is proposed.The computational fluid dynamics numerical simulation method is used to construct a three-dimensional geometric model including inlet flue,guide plate and rectifier device for the selective catalytic reduction denitrification flue of a 350 MW coal-fired boiler.The standard k-ε turbulence model and porous medium model are used for simulation analysis.[Results]The simulation results indicate that the original flue exhibited pronounced flow separation,recirculation,and large-scale vortical structures in the expansion section and multiple bends,leading to a highly non-uniform velocity distribution at the catalyst inlet,with a velocity deviation coefficient of 40.6％and more than 30％of the cross-section occupied by low-velocity regions.Comparative analysis of the four optimization schemes shows that the combined application of dynamic guide vanes and adjustable throttling plates effectively improves the flow path in the bend region,suppresses local high-velocity impingement,and significantly reduces low-velocity stagnant zones.Among the evaluated cases,the optimal scheme(Scheme 4)reduces the velocity deviation coefficient to 13.2％,increases the proportion of medium-velocity regions to 75％,and simultaneously decreases the overall pressure drop by approximately 5％-7％compared with the original configuration.In addition,the distribution of fly ash concentration and guide-vane erosion becomes more uniform,demonstrating comprehensive improvements in flow uniformity,hydraulic performance,and wear resistance.[Conclusion]This research validates the practicality and feasibility of dynamic guide vanes technology in optimizing SCR denitrification systems,providing a theoretical basis and engineering reference for enhancing denitration efficiency,controlling ammonia slip,and extending catalyst service life.