催化裂化装置沉降器顶旋升气管外壁结焦过程的分析

通过旋风分离器升气管外壁表面的粉灰沉积试验,进一步说明催化裂化装置沉降器顶旋升气管外壁结焦的原因是管壁表面存在着低速的"滞流区"。具有结焦倾向的油气液滴和细催化剂颗粒在气流的湍流扩散和环行空间二次涡等多种因素作用下进入"滞流层"并沉积在升气管表面,尤其是顺压力梯度区域。这些具有结焦倾向的油气液滴吸咐在催化剂细粉上形成结焦中心,并逐渐长大形成焦块。这种焦块对催化裂化装置的运行具有潜在的危害性。

ANALYSIS OF COKING COURSE ON THE EXIT-TUBE EXTERNAL WALL OF CYCLONE IN FCC DISENGAGER

Through the test of fines deposition on the exit-tube external wall of cyclone in disengager, it was found that the coking was caused by the low-velocity stagnation layer formed on the wall. Catalyst fines carried by the gas and oil drops with coking potential entered the stagnation layer acted by various factors such as turbulent diffusion and secondary turbulence in the annular space of the cyclone, and deposited on the external wall surface of the exit-tube especially along the region of pressure-gradient. The oil drops adsorbed on the fines formed a coking center and gradually grown as coke block. The coke block could cause potential danger on FCC running.