孟剑

摘 要：对一种BB2结构形式高温辐射进料泵的非驱动端机械密封在运行过程中的渗漏故障进行分析得出，机械密封泄漏故障的根本原因是密封腔泵送介质压力偏高，内侧密封冲洗液（P32）及外侧密封冲洗系统（P53A）隔离液压力偏小，无法满足冷却润滑密封动静环要求，导致机械密封长时间在高温、高压状态下运行失效。为消除泵运行安全隐患，对泵的降压系统进行了模型分析与优化设计，将密封腔体介质压力由原来的1.2 MPa降低至约0.3 MPa，实现了密封冲洗液对密封动静环的充分冷却和润滑，延长机械密封使用寿命，提高机组安全运行的可靠性，有效降低了运维成本。

关键词：辐射进料泵;节流套;泄压系统;泄漏量

中图分类号：TQ520.5文献标识码：A文章编号：1003-5168（2020）16-0047-04

Abstract： Based on the analysis of the leakage of the mechanical seal at the non drive end of a BB2 structure high temperature radiation feed pump in the process of operation， it was concluded that the root cause of the leakage of the mechanical seal was the high pressure of the pumped medium in the seal cavity， the low pressure of the internal seal flushing fluid （P32） and the external seal flushing system （p53a） isolating fluid， which could not meet the requirements of the dynamic and static rings of the cooling lubrication seal， resulting in the mechanical seal fails in high temperature and high pressure for a long time. In order to eliminate the potential dangers of pump operation ， the model analysis and optimization design of the pump's pressure reduction system were carried out， and the medium pressure of the sealing cavity was reduced from the original 1.2 MPa to about 0.3 MPa， which realized the sufficient cooling and lubrication of the moving-fix ring ， and extended the work life of the mechanical seal， improved the reliability and safety of the machine unit， reduced the cost of operation and maintenance efficiently.

Keywords： radiation feed pump;throttle sleeve;pressure relief system;leakage

延遲焦化装置中辐射进料泵，也称为加热炉进料泵，是焦化装置的关键设备，其功能是将300 ℃以上的焦化渣油从分离塔底抽出，经由燃烧炉辐射室快速升温后，送至焦炭塔反应生焦。该泵的特点是流量大、扬程高、功率消耗大，是延迟焦化装置用电大户。某炼化厂延迟焦化装置中，采用BB2结构形式的加热炉进料泵共3台，并联安装，两开一备运行，泵送出来的渣油经出口截止阀后分成8个支路进入燃烧炉升温，然后再进入焦炭塔，在8个支路上设置调节阀控制流量。3台泵自投入运行以来，泵的性能指标良好;但是，非驱动端机械密封每运行2个月左右，便出现渗漏现象，对故障机械密封解体检查后发现，两道密封的动静环均存在不同程度的磨损现象，此项指标与泵厂家所提供的维修计划中机械密封使用寿命8 000 h以上严重不符[1]。……