As one of the most important auxiliary systems of a circulating fluidized bed boiler, the limestone pneumatic conveying system is of great significance to its operation. Maldistribution of powder in the different injecting ports seriously limits inner-furnace desulfurization performance owing to inefficient mixing of limestone powder and SO₂. The gas–solid flow characteristics of an industrial-scale multiple-branching limestone-conveying pipeline system of a 200 MW circulating fluidized bed boiler were studied using a computational particle fluid dynamics method. The maldistribution intensity was studied under different operating conditions of air velocity and particle mass flow rate. Simulation results indicated that when the air velocity increased, the maldistribution was mitigated, but when the particle mass flow rate increased, the maldistribution strengthened. To solve this problem, two improved schemes were proposed: adding a deflector at different angles and changing the height of pipeline distributor. According to the simulation, the maldistribution could be efficiently mitigated using a distributor height in the range of 100–120 mm and a deflector angle of 10°–30°.

作为循环流化床锅炉最重要的辅助系统之一，石灰石气动输送系统对其运行具有重要意义。由于石灰石粉与SO ₂混合不充分，粉末在不同注入口中的分布不均严重限制了炉内脱硫性能。利用计算粒子流体动力学方法研究了200 MW循环流化床锅炉工业规模多分支石灰石输送管道系统的气固流动特性。在空气流速和颗粒质量流量的不同操作条件下研究了分布不均的强度。仿真结果表明，当风速增加时，分布不均得到缓解，而当颗粒质量流量增加时，分布不均得到增强。为了解决这个问题，提出了两种改进的方案：在不同的角度增加一个导流板并改变管道分配器的高度。根据模拟，分配器高度在100–120 mm范围内且偏转角为10°–30°时，可以有效缓解分布不均。