催化裂化沉降器空间内油气停留时间的分布

以0．8Mt／a催化裂化装置的沉降器为例，考察了沉降器空间内油气平均停留时间的分布。在实验室模型验证的基础上，采用RSM模型和标量输运方程进行了数值模拟研究。结果表明．对于粗旋风分离器和顶部旋风分离器之间敞口联接的沉降器。粗旋风分离器升气管出口与顶部旋风分离器人口间有一最佳距离。由于粗旋风分离器与顶旋风分离器非一对一的布置，导致各顶旋风分离器人口气量分配不均，需要改进。由粗旋风分离器料腿进入沉降空间的油气的长时间停留是阻止沉降器内油气平均停留时间缩短的主要问题；其次则为由粗旋风分离器升气管进入沉降空间的油气的停留时间。其它部位油气的停留时间占总停留时间的份额较小。因此，其结构改进的重点应为粗旋风分离器料腿部分以及粗旋风分离器和顶旋风分离器间的联接形式。

RESIDENCE TIME DISTRIBUTION OF OIL VAPOR IN A FCC DISENGAGER

Average residence time distribution of oil vapor in a disengager of a 0.8 Mt/a FCC unit was studied. After experimental validation in a small cold model of disengager, the RSM model combined with scalar transport equation was used to simulate steady flow field and residence time distribution of oil vapor. The simulation results revealed that an optimized distance existed between the outlet of the exit tube of the rough-cut cyclone and the inlet of the secondary cyclone. As asymmetric installation of the rough-cut cyclones in the disengager, mass flux is unequally distributed into the secondary cyclones. Long residence time of oil vapor from the dipleg of rough-cut cyclone is the primary controversy to reduce its total residence time in disengager, and long residence time of oil vapor from the exit tube of rough-cut cyclone is the second controversy. Other residence time of oil vapor is only a relatively small part of the average residence time. So concentration of configuration innovation should be focused on the dipleg of rough-cut cyclone and the connection between the rough-cut cyclone and the secondary cyclone.