催化裂化沉降器旋流快分系统内两种旋流头的性能对比

Performance comparison of two newly developed disengager arms in vortex quick separator for FCC disengager

通过冷态对比实验,研究了旋流快分系统(VQS)内两种新型旋流头的分离性能,结果表明B型旋流头采用大弧切向出口后,对含尘气流具有加速旋转的作用,可使颗粒喷出后获得更高的切向速度,从而提高系统的分离效率。采用Fluent软件对VQS内气固两相流进行了数值模拟,重点考察了A、B型旋流头的流场分布和分离特性。模拟结果表明:含尘气流由B型旋流头喷出后,切向速度较大,离心力较强,增加了颗粒在稳定分离区内分离的概率;同时,含尘气流喷出后气量大部分集中在封闭罩内壁附近下行流动,下行轴向速度较大,有利于颗粒下行分离。此外,相比于A型旋流头,B型旋流头的分离优势在于可大大提高对中粗颗粒的捕集能力。因此工业应用中推荐采用B型旋流头,以更好地满足工业生产的需求。

The separation performance of the newly developed disengager arms （models A, B） in vortex quick separator （VQS） for FCC disengager was tested experimentally. The results indicated that the performance of model B was better than that of model A. Affected by the structure of model B, the dusty airflow can rotate at a higher speed and gain stronger tangential velocity after ejecting from the outlet of disengager arms. Consequently, the dusty airflow in model B can get stronger centrifugal force, which led to the improvement of separation efficiency in VQS. The gas-solids flow in VQS was numerically simulated on the platform of commercial computational fluid dynamics （CFD） software, Fluent 6.1. Numerical calculation showed that in model B, not only the tangential velocity in the outer vortex area was higher, hut also the axial velocity in the downward-flow zone was also higher, which also implied that model B had stronger centrifugal force and higher separation efficiency. Furthermore, the grade efficiency of coarse particles can be improved greatly in model B. Hence, model B was recommended as the optimal disengager arms in industrial application.