喷氨格栅后加装V型导流板的数值研究

氨气与烟气混合均匀与否对脱硝效率及氨逃逸情况影响显著。以某燃煤电厂600 MW机组选择性催化还原（SCR）烟气脱硝系统为研究对象，使用Fluent软件，在无导流板、氨气-空气混合物流速为0.5、0.8 m/s情况下，对不同烟气流速时的SCR脱硝系统气流速度进行了数值计算，得到最佳流速组合为烟气流速3.7 m/s，氨气-空气混合物流速为0.5 m/s。以此为基础，在喷氨格栅后拟加装V型扰流板（布置方式为横向或纵向），以使氨气与烟气混合均匀，对速度、流场均匀性、压力、压降等数值进行模拟，结果为横向布置的V型扰流板效果较好，其可使氨气与烟气混合均匀，系统压降损失达到设计要求。

Numerical Study on the Installation of V-Shaped Guide Plate behind theAmmonia Injection Grid

The mixture evenness of ammonia and flue gas has great impacts on both the denitrification efficiency and the ammonia slip. By taking the example of the selective catalytic reduction (SCR) flue gas denitrification system of a 600-MW coal-fired power plant as the study case, the Fluent software is used to calculate the air mixture flow rate at various flue gas velocities with no spoiler and the ammonia-air mixture flow rate at 0.5 and 0.8 m/s respectively. The optimal flow rate combination is obtained as flue gas velocity of 3.7 m/s and ammonia-air mixture flow rate of 0.5 m/s. Then, the V-shaped spoiler(horizontally or vertically arranged) is installed behind the ammonia injection grid to make the ammonia mixed evenly with the flue gas. Numerical simulation is conducted on velocity, flow field uniformity, pressure and pressure drop. From the simulation results the horizontal V-shaped spoiler exhibits satisfactory performance in mixing the ammonia evenly with the flue gas so as to meet the designed requirements of system pressure drop.