焦化热油泵机械密封泄漏分析与对策

Analysis of hot oil pump mechanical seal leakage in delayed coking unit and countermeasures

通过热油泵机械密封升级,沧州炼化焦化装置将9台热油泵进行了材质和结构升级。机械密封升级改造后使用效果不太理想,辐射进料泵、分馏塔底循环泵、蜡油泵频繁出现机封泄漏。通过现场观察,机封泄漏主要是密封油外漏。打开泄漏机封发现密封面静环存在崩边现象,蜡油泵机械密封波纹管存在结焦现象。分析机封泄漏原因,认为现场封油系统压力偏高;机械密封密封面的损坏可能由于封油品质差导致;机械密封波纹管结焦导致其紧力不足,上述原因导致机械密封泄漏。通过实施调整密封油压力,机械密封的重新选型,摩擦副材质升级,提高机械密封波纹紧力,机械密封密封面变窄,管更新辅助系统,疏通机泵大盖冷却水等措施,基本达到了高温热油泵机械密封无泄漏。

The material and construction of 9 hot oil pumps in delayed coking unit in SINOPEC Cangzhou Petrochemical Company were upgraded by upgrading the mechanical seals of hot oil pumps. The operation of the hot oil pumps was not satisfactory after upgrading of mechanical seals. The radiation feed pump, recycle pump at bottom of distillation tower and wax oil pump experienced frequent leakages. The site investigation found that the mechanical seal leaking was mainly the leaking of seal oil. The opening of mechanical seal found the edge collapse of static seal ring and coking on mechanical seal bellows of wax oil pump. The analysis of the leaking concluded the causes were the high pressure of seal oil system and low quality of seal oil which damaged the mechanical surface. In addition, the coking on the mechanical seal bellows reduced the tightening force, which led to the leaking of mechanical seal. The leaking of mechanical seals of hot oil pumps was basically eliminated by the end of 2013 by adjustment of seal oil pressure, re-selection of mechanical seal, upgrading of materials, increasing tightening force of seal bellows, replacement of auxiliary system and improve- ment of cooling water system, etc. The maintenance costs were saved, and safe reliable operation of equipment was ensured.