省煤器出口加挡板对除灰性能影响的数值模拟

Numerical simulation on effect of ash removal by adding baffle at outlet of economizer

建立了某660 MW机组省煤器出口与SCR入口之间烟道的三维数值模型,通过模型研究了飞灰颗粒的运动规律。模拟结果表明:入射位置偏向省煤器出口中后部并且粒径较大的飞灰颗粒易被灰斗捕集,入射位置偏向省煤器出口前部的飞灰颗粒不易被捕集;于省煤器出口布置一块挡板可捕集入射位置偏向省煤器出口前部的大粒径飞灰颗粒,同时也能提高系统的飞灰捕集率,此时SCR入口烟道设计成向上倾斜可减小系统的压降。当挡板布置角度为65°,水平烟道倾斜角度为30°时,系统的飞灰捕集率由38.6%增加至48.4%,系统的压降增加192 Pa。

A three dimensional numerical model of flue between the outlet of economizer and the inlet of SCR of660 MW power unit was established,the motion law of fly ash particles was studied by the model. The results show that the incident position of fly ash particles which biased towards the rear of the outlet of economizer and with large diameters were easily trapped by the hopper. The incident position of fly ash particles which biased towards the front of the outlet of economizer and with large diameters can be trapped by adding a battle at the outlet of economizer,meanwhile,the fly ash capture rate of the system was also increased,at this point,the SCR inlet duct is designed to upward can reduce the pressure drop of the system. When the baffle angle is 65°,horizontal flue inclination angle is 30°,the fly ash capture rate of the system increased from 38. 6% to 48. 4%,the pressure drop of the system increased by 192 Pa.