热交换器不锈钢管束断裂失效分析

采用宏观分析、金相检验、断口宏观及微观分析以及能谱分析等方法,对某炼油厂裂化车间4台热交换器不锈钢管束先后发生大面积断裂的性质及原因进行了分析。结果表明:该热交换器管束断裂是由在交变载荷和腐蚀介质作用下发生的由外向内的腐蚀疲劳开裂引起的;腐蚀疲劳裂纹起始于管外壁的点蚀坑等应力集中处,促进腐蚀疲劳裂纹扩展的管束外部介质主要是Cl^-和H_2S;裂纹先以腐蚀疲劳开裂方式扩展,而后又呈典型的应力腐蚀开裂方式继续扩展,当应力腐蚀裂纹扩展达到管束断裂强度时便发生断裂。最后提出了预防管束断裂的措施及建议。

炼化装置水冷器应用不锈钢管束的可行性

水冷器广泛应用于各行业的过程装置,但管束内漏却一直困扰着装置的长周期运行。炼油化工装置由于水冷器的碳钢管束使用年限短,相继用不锈钢管束更换碳钢管束,却也同样有不锈钢水冷器氯离子应力腐蚀开裂的问题。为此,通过检索相关文献,借鉴不锈钢水冷器使用的经验,结合炼油化工装置中水冷器用不锈钢管束更换碳钢管束的案例,探讨水冷器应用不锈钢管束的可行性和合理性,以保障装置的长周期运行。

无翅片椭圆不锈钢波纹管管束空气冷却器的研究

空气冷却器采用无翅片椭圆不锈钢波纹管管束替代传统的翅片管管束 ,是空气冷却器设计制造的技术革新。实验数据证明 ,此项发明专利技术基本成熟 ,可使空气冷却器的耐久性、可靠性、耐腐蚀性、耐污染性等各项性能指标有大幅度提高 。

炼制沙轻-胜利原油常减压塔顶冷换设备的腐蚀

上海石化股份有限公司 2号常减压蒸馏装置 ,自 2 0 0 0年加工沙轻 -胜利高硫混合原油后 ,减顶预冷器EC - 10 4和常顶油气换热器E - 5 0 0 2均因腐蚀而发生泄漏。当加工上述混合原油时 ,其脱后原油盐含量大于 5mg/L ,三顶冷凝水中S2 -含量很高 ,因此减、常顶系统的腐蚀为H2 Cl-H2 S -H2 O型腐蚀。进行破乳剂优化筛选 ,原油合理调配以及选用了 3RE60或 2 2 0 5双相不锈钢管束后 。

炼化装置循环水污染与控制

炼化装置广泛应用水冷器,但水冷器内漏失效不仅是制约装置长周期运行的瓶颈,而且因泄漏流失的工艺介质又污染循环水,加剧装置设备与管道的腐蚀损伤,由此形成腐蚀泄漏—污染水质—加剧腐蚀的恶性循环。从水冷器设计的合理性、制造的可靠性、使用的完好性及水质的符合性等方面对内漏污染循环水的控制进行讨论。结果表明:通过合理应用不锈钢管束,保证循环水质的监测考核,不仅可以减少水冷器内漏对循环水的污染,而且可以方便解决碳钢水冷器管束经常泄漏的难题,由此支持装置的长周期运行。

Fatigue Analysis of Steel Catenary Risers Based on a Plasticity Model

The most critical issue in the steel catenary riser design is to evaluate the fatigue damage in the touchdown zone accurately. Appropriate modeling of the riser-soil resistance in the touchdown zone can lead to significant cost reduction by optimizing design. This paper presents a plasticity model that can be applied to numerically simulate riser-soil interaction and evaluate dynamic responses and the fatigue damage of a steel catenary riser in the touchdown zone. Utilizing the model, numerous riser-soil elements are attached to the steel catenary riser finite elements, in which each simulates local foundation restraint along the riser touchdown zone. The riser-soil interaction plasticity model accounts for the behavior within an allowable combined loading surface. The model will be represented in this paper, allowing simple numerical implementation. More importantly, it can be incorporated within the structural analysis of a steel catenary riser with the finite element method. The applicability of the model is interpreted theoretically and the results are shown through application to an offshore 8.625 steel catenary riser example. The fatigue analysis results of the liner elastic riser-soil model are also shown. According to the comparison results of the two models, the fatigue life analysis results of the plasticity framework are reasonable and the horizontal effects of the riser-soil interaction can be included.