催化裂化装置沉降器跑剂原因分析及对策

Cause analysis and countermeasures for the agent runout of the disengager of FCCU

对某炼油厂1.7 Mt/a催化裂化装置催化剂藏量和沉降器二级旋风分离器(顶旋)压力降快速下降及油浆固体含量快速上升等问题的原因进行了分析,并提出了解决措施。受台风过境的影响,该装置操作发生了波动,总催化剂藏量突然开始下降,沉降器顶旋压力降由正常的10.19 kPa降至8.98 kPa,油浆固体含量(油浆中固体颗粒的质量浓度)由正常的2~3 g/L增至28.41 g/L,最高上升至92.38 g/L。停工检查发现,顶旋的6个翼阀中有4个翼阀阀板被焦块卡住,翼阀不能正常开启和关闭,导致料腿堵塞不能排料,发生催化剂大量跑损的故障。经分析判断,堵塞料腿和翼阀的焦块是顶旋升气管外壁脱落的焦块。分析这些焦块产生的原理:重组分油气液滴沉积在器壁表面,发生脱氢缩合反应形成焦,后与催化剂颗粒结合逐渐增大、增厚。综合分析各种防焦措施,采用防焦导流片技术解决了顶旋升气管外壁结焦脱落的问题,保障了装置的长周期运行。

The reasons for the rapid decrease in catalyst storage and pressure drop of the cyclone at the top of settler in a 1.7 MM TPY FCCU of a certain refinery,as well as the rapid increase in solid content of the oil slurry were analyzed,and solutions were proposed.Due to the impact of the typhoon crossing,the operation of the unit experienced fluctuations,and the total catalyst storage suddenly began to decrease.The pressure drop of the cyclone at the top of settler decreased from 10.19 kPa(normal value)to 8.98 kPa,and the solid content of the oil slurry increased from 2~3 g/L(normal value)to 28.41 g/L,with a maximum of 92.38 g/L.During the shutdown inspection,it was found that 4 out of the 6 top cyclone wing valves were stuck by coke blocks,causing the wing valves to fail to open and close normally,resulting in blocked material legs and inability to discharge,resulting in a large amount of catalyst loss.After analysis,it was determined that the coke blocks that blocked the material legs and wing valves were the coke blocks that fell off from the outer wall of top cyclone riser.The principle behind the formation of these coke blocks was analyzed.Heavy component oil vapor droplets deposit on the surface of the reactor wall,undergo dehydrogenation condensation reaction to form coke,and gradually increase and thicken when combined with catalyst particles.After comprehensive analysis of various anti coking measures,the anti coking guide plate technology was adopted to solve the problem of coking and detachment on the outer wall of the top cyclone riser,ensuring the long-term operation of the unit.