Research On Optimization Of Flow Field Uniformity In SCR Denitrification Flue Of Coal-fired Power Plant

The uniformity of the flow field at the inlet of the first layer of the catalyst in the SCR denitrification flue has an important effect on the full mixing of the reducing agent such as flue gas and ammonia in the system and the denitrification efficiency of the system.Based on this situation,in this paper,the multi-point measurement of the flow field is firstly performed on the laboratory's existing modeled bench with a ratio of 15:1 according to the actual denitration flue.The results show that the velocity field of the first layer of catalyst is extremely uneven.The non-uniform coefficient of speed is high.Then this paper uses the Fluent software to perform numerical simulations on the modeling bench.The k-? double equation model is used to simulate the turbulent motion of the flue gas,and the structure of the SCR denitrification system is optimized by optimizing the deflector plate to study the influence of the position and angle of the deflector on the inlet flow field of the catalyst.Then the paper got the optimized installation position and angle of the deflector.After that,the multi-point measurement of the flow field was performed on the inlet flow field of the catalyst.The results showed that the uniformity of the inlet flow field of the catalyst after optimization was greatly improved.Its Cv value satisfies the requirement for the uniformity of the flow field at the inlet of the catalyst layer.At the same time,for the different working conditions of boilers,an improvement plan was proposed to increase the uniformity of the inlet flow field of the catalyst by adding movable angled deflectors to adjust the boiler Ioad.By adjusting the rotation angles of several movable deflectors to form different deflectors arrangement schemes,the non-uniform coefficient of velocity of the first layer catalyst entrance under various boiler load can be less than 15%.Then,experimental verification was performed on the modeled bench.Finally,the numerical simulation of the SCR denitrification system in the actual operation of Guoxin Jingjiang Power Plant was carried out.Samely,a modification scheme was proposed to improve the uniformity of the inlet flow field of the catalyst by adding the adjustable angle deflector.The simulation results show that the adjustable angle deflector proposed in this paper can control the inlet velocity non-uniformity coefficient of the catalyst to 15%or less for a variety of assumed non-uniform inlet velocity fields,which fully satisfies the uniformity of the catalyst layer to the inlet flow field.It is of great significance to improve the life of the catalyst layer and improve the denitration efficiency of the catalyst layer.