乙烯裂解气压缩机高压缸干气密封泄漏原因分析及解决措施

Cause analysis of dry gas seal leakage on high pressure cylinder of ethylene cracking compressor and solutions

针对某裂解气压缩机高压缸干气密封泄漏导致机组联锁跳车和乙烯装置停车的问题,对高压缸干气密封进行拆解,通过拆检干气密封,发现在弹簧座外圆、密封筒体内表面及推环内、外圈表面上有磨痕,一级密封动静环磨损及损坏;高压缸轴位移从0.098 mm减小至-0.268 mm,一级密封泄漏量从16.32 Nm^(3)/h增大至45.44 Nm3/h,判断出推环卡涩引起动静环摩擦及动环出现热崩裂;对压缩机密封筒体错边及干气密封部件磨痕等进行了分析,确认了推环与弹簧座内孔间隙变小是造成推环卡涩的根本原因;采用更换密封,对弹簧座外圆进行加工,使外圆与密封腔体之间的间隙从原来0.1 mm增大至0.25 mm等措施,消除了干气密封动静环摩擦损坏的潜在风险,保障了机组正常稳定运行。

In view of the problems of the unit interlocking trip and stop of ethylene device due to the leakage of dry gas seal in the high pressure cylinder of the ethylene cracking gas compressor,by disassembling the dry gas seal of the high-pressure cylinder and removing the dry gas seal,the grinding marks on the outer circle of the spring seat,the inside surface of the sealing cylinder and the inner and outer surface of the push ring and the wear and damage of the rotating ring and stationary ring of the primary gas seal were found.The shaft displacement of high pressure cylinder was decreased from 0.098 mm to-0.268 mm and primary seal leakage flow was increased from 16.32 Nm3/h to 45.44 Nm^(3)/h,therefrom it was confirmed that the push ring was stuck,causing the friction between rotating ring and stationary ring and thermal cracking of rotating ring.The misalignment of compressor sealing cylinder and wear marks of dry gas seal parts were analyzed,and it was confirmed that the reduced gap between push ring and spring seat was the fundamental cause of push ring seizure.By replacing the dry gas seal and processing the outer circle of the spring seat to make the gap between the outer circle and the sealing cavity increase from 0.1 mm to 0.25 mm,the potential risk of friction damage to the rotating and stationary rings of the dry gas seal was eliminated,thus the normal and stable operation of the unit was ensured.