催化裂化VQS改造探讨

Discussion on technical revamp of FCC VQS

分析了催化裂化装置沉降器跑剂和结焦原因。介绍了改造情况:沉降器提升管出口采用"VQS快分+单级旋分"形式;顶旋分器和VQS快分封闭罩集中布置于沉降器壳体内;将VQS封闭罩外6个平衡管截短1 100 mm,使平衡管口远离油气区;将旋分器下部料腿直径由DN450 mm改为DN350 mm,旋分器翼阀改为DN350 mm的半覆盖式翼阀。将溢流密封圈的槽口从6个增加到12个,并与封闭罩的槽口相对应;将原封闭罩外1个松动蒸汽环更改为2个单独进汽半环,并减少松动蒸汽环上的蒸汽喷嘴面积。装置自大检修开工以来,已平稳运行12个月,平均加工负荷已提高到115%,沉降器运行正常。预计每年可节省1.0 MPa蒸汽25.2 kt。

The causes of catalyst loss and coking of disengager of FCC unit are analyzed, and technical revamp is introduced. In the revamp, ＂VQS quick separation ＋ single stage cyclone＂ was installed at the outlet of riser. The seal boots of top cyclone and VQS quick separation were centrally arranged in disengager shell. The 6 balance pipes outside the closed cap were shortened by 1 100 mm so that the outlets of balance pipes are away from oil vapor zone. The diameter of dip leg of cyclone separator was changed to DN350 mm from DN450 mm. The wing valve of cyclone separator was revamped to semi-covering wing valve of DN350 mm diameter. The number of daps of flooding seal ring was increased to 12 from 6 and correspond to daps of closed caps. One aeration ring outside of closed cap was replaced with 2 independent semi steam rings and the area of steam nozzles on aeration steam ring were reduced. Ever since the overhaul, the FCC unit has been running smoothly at 115% of normal capacity, and the operation of disengager is normal. The predicted annual saving of 1.0 MPa steam is 25,200 tons （ based upon on-stream factor of 8 400 hours a year）.