炼油工业中的环烷酸腐蚀

高酸值原油加工过程中设备的腐蚀问题和防腐蚀新技术受到相关部门的高度重视。环烷酸腐蚀的规律比较复杂,迄今对很多问题还不甚了解。通过对环烷酸腐蚀机理的分析,指出原油组成、操作温度、流速和流动状态及设备材质等是影响环烷酸腐蚀的重要因素。还介绍了加工高酸值原油中的防腐蚀技术。     

模拟炼油环境中Q235钢和Cr5Mo钢表面硫化物膜稳定性及动态冲刷腐蚀行为研究

通过静态浸泡腐蚀实验装置和高温动态冲刷实验装置分别研究了硫化物膜在多种模拟炼油介质中的稳定性以及动态冲刷条件下Q235钢和Cr5Mo钢的耐冲刷腐蚀性能。结果表明,硫化物膜的形成过程是一个动态平衡过程。在无硫补充的条件下,硫化物膜快速溶解。动态冲刷作用下,Cr5Mo钢耐动态环烷酸冲刷腐蚀性能明显好于Q235钢,溶液酸值越大两者的差别越明显。     

高温环烷酸腐蚀机理与控制方法研究进展

高温环境下环烷酸的腐蚀一直是炼油工业急需解决的一个重要的实际问题.尽管关于环烷酸腐蚀的研究一直没有间断,但因其腐蚀因素众多,其腐蚀机理仍未有定论.本文综述了高温环烷酸的腐蚀机理及其影响因素、腐蚀试验与控制方法的研究进展:认为原油类型和组成、操作温度、设备材质、流速流态、操作时间等对环烷酸腐蚀有着重要的影响.针对影响环烷酸腐蚀的因素,开展现场试验、实验室模拟和加速试验对于环烷酸腐蚀的研究有着重要的意义:现有的各种控制方法均存在不足,需进一步加强高温环境下环烷酸的腐蚀行为和规律的研究.     

环烷酸和硫化氢腐蚀体系的热力学分析

从热力学角度讨论了环烷酸和硫化氢组成的腐蚀体系的热力学性质.结果表明:含高硫、高酸值的原油在温度小于398.98 K时,所形成的FeS膜对环烷酸的侵蚀具有一定的保护作用,高于此温度将丧失保护作用.温度、浓度的变化不同程度的影响腐蚀产物的组成,讨论了FeS在环烷酸中可能的溶解机理,探讨了选择成膜型缓蚀剂的原则.     

常减压装置常用钢材在高温原油馏分中的腐蚀研究

利用高压釜模拟常减压装置中的腐蚀环境,采用腐蚀失重法并结合SEM,研究了4种常减压装置常用钢材在高温原油馏分中的腐蚀行为,分析了馏分、材质、温度的影响规律。结果表明,原油馏分的酸值、S含量和盐含量越高,对20钢腐蚀性越强,3种原油馏分对20钢的腐蚀性强弱为：脱盐后原油＞常二线馏分＞常一线馏分。提高钢材中Cr,Ni和Mo等合金元素的含量有助于提高其抗腐蚀能力,4种钢材在高温原油馏分中的抗腐蚀性能优劣为：316钢＞304钢＞1Cr5Mo钢＞20钢。温度对钢材在高温原油馏分中的腐蚀行为会产生多方面的影响,腐蚀速率总体上随着温度的升高而增大,某些温度范围内可能出现腐蚀速率极值。     

炼油设备中的环烷酸腐蚀

<正> 近年来,国产原油性质有很大变化,如重质原油增多、原油酸质升高、含硫量增加,由此炼油设备受到严重腐蚀。环烷酸冲刷腐蚀就是设备损坏的重要原因之一。炼油工作者对如何控制环烷酸腐蚀已做了许多工作,但在长达60年的时间内,所发表的技术文献大多为腐蚀事例,有关环烷酸腐蚀的本质和规律却论述得很少。本文试图从已有文献、数据探讨环烷酸冲刷腐蚀及其控制。     

原油高温腐蚀性能研究

本文综述了国内外原油高温腐蚀性能的研发现状,分别归纳分析了高温硫腐蚀和高温环烷酸腐蚀在腐蚀机理及其影响因素、腐蚀预测、以及腐蚀控制措施方面的研究进展。同时探讨了存在的问题和可能的重点研究方向。     

信息集萃

中科院金属所参与中石化加工高酸原油防腐蚀联合攻关由中石化集团公司科技开发部主办、中科院金属所承办的“中国石化集团加工高酸原油防腐蚀对策”项目研讨会于2007年1月6日在沈阳召开。此次会议为中石化高酸原油防腐蚀加工提供了解决方案,为组织攻关项目奠定了基础。由于国内原油紧缺,国际原油价格居高不下,为了降低原油加工成本,中石化集团公司未来将进口低价格、高酸值原油,其酸值达到3．7mg KOH/g。高酸值原油加工时腐蚀性强,尤其是高温环烷酸腐蚀是炼油装置安全、稳定、长周期运     

碳钢在高温环烷酸介质中冲刷腐蚀行为

研究了A3碳钢在高温环烷酸介质中的冲刷腐蚀行为，并考察了其在工业炼油环境中的抗冲蚀性能。结果表明，酸值、温度、流速是影响碳钢环烷酸冲刷腐蚀行为的主要因素，它们通过影响环烷酸分子向金属表面的传输、在金属表面的吸附、表面活性反应及腐蚀产物的剥离等过程来影响冲刷腐蚀的程度。     

加工高酸原油炼油设备防腐技术新进展

介绍了加工高酸原油炼油设备防腐蚀技术的进展和应用情况.主要采取混炼、化学物理方法脱酸、材质升级、加注缓蚀剂以及进行有效的腐蚀监测及预测技术是减轻环烷酸危害的有效手段,并且在抑制高温环烷酸腐蚀的缓蚀剂产品中,磷系好于非磷系,但以混合型最为有效.     

Erosion‐corrosion of Q235 and 5Cr1/2Mo steels in oil with naphthenic acid and/or sulfur compound at high temperature

The erosion‐corrosion behaviors of Q235 steel and 5Cr1/2Mo steel in oil with naphthenic acid and/or sulfur compound at high temperature were studied in a hot oil loop simulating oil refining environments. The effects of impinging flow rate, incidence angle, and total acid number (TAN), and sulfur content on erosion‐corrosion behavior were assessed. The eroded surfaces were characterized by scanning electron microscopy (SEM) and XPS. The results showed that both corrosion resistance and hardness of steels play an important role in combating erosion‐corrosion. Sulfide films formed on the surface were significant in understanding the erosion‐corrosion behavior when both naphthenic acid and sulfur compound were present. Erosion‐corrosion regimes were determined on the basis of mechanism analysis of the damage process.     

碳钢和不锈钢在高温环烷酸介质中的腐蚀行为

采用失重法和表面分析研究了碳钢和不锈钢在高温环烷酸油介质中的腐蚀行为规律。结果表明：酸值和温度是影响金属环烷酸腐蚀行为的主要因素,其反应动力学遵循Arrhenius公式。腐蚀速度随着温度的上升而增加,同一温度下酸值影响气相腐蚀速度与液相腐蚀速度之间的关系。腐蚀速度与酸值的平方根成线性关系。随着腐蚀时间的增加,腐蚀速度迅速降低,最后趋于稳定的腐蚀速度。     

High temperature naphthenic acid corrosion and sulphidic corrosion of Q235 and 5Cr1/2Mo steels in synthetic refining media

The corrosion of Q235 and 5Cr1/2Mo steels in synthetic refining media containing naphthenic acid and/or sulphur compounds was studied to evaluate naphthenic acid corrosion (NAC), sulphidic corrosion (SC), and their interaction. Corrosion dependencies on the test duration, temperature, total acid number (TAN) and content of sulphur compound were assessed. Specimens after NAC and SC tests were characterized by SEM/EDX, and XRD. It is found that in liquid phase of media containing only naphthenic acid and at temperature about 230 °C, 5Cr1/2Mo and Q235 steels have almost the same NAC rate, and above 230 °C, 5Cr1/2Mo has a higher NAC rate than Q235 has due to the higher NAC activation energy (63.2 kJ mol⁻¹) of 5Cr1/2Mo than that of Q235 (54.0 kJ mol⁻¹), indicating that increasing temperature accelerates NAC rate of 5Cr1/2Mo more than that of Q235. In oil containing only dimethyl disulphide, the growth of SC film follows parabolic kinetics, and the film of Q235 grows faster than that of 5Cr1/2Mo while SC rate of Q235 is higher than that of 5Cr1/2Mo. In oil containing both naphthenic acid and dimethyl disulphide, 5Cr1/2Mo has a lower corrosion rate than Q235 has. On the basis of “naphthenic acid corrosion index” (NACI), the benefits of 5Cr1/2Mo over Q235 should ascribe to that the pseudo-passive film for 5Cr1/2Mo has better NAC resistance than that for Q235. This is close related to the existing of additional chromium sulphide (Cr₅S₈) on the pseudo-passive film of 5Cr1/2Mo, in contrast with the pyrrhotite (Fe₇S₈) and troilite (FeS) on the film of Q235.     

环烷酸腐蚀影响因素及其相互作用

介绍了炼化工业中环烷酸腐蚀的背景和现状与环烷酸的腐蚀机理,主要探讨了酸值、硫含量、温度、流速等影响环烷酸腐蚀速率的重要因素,并结合金属材质、原油种类对其相互间的作用进行了分析。建议建立统一、合理的研究及测试技术规范,针对具体案例具体分析,以期得出可靠的、可比性较强的数据供工程实践参考。     

Naphthenic acid corrosion characteristic and corrosion product film resistance of carbon steel and Cr5Mo low alloy steel in secondary vacuum gas oil

Although naphthenic acid corrosion (NAC) has been studied for many years, the mechanism of NAC is not fully understood. The objective of this paper is to study high-temperature NAC in secondary vacuum gas oil of an industrial crude oil vacuum distillation tower. A high-temperature autoclave was applied to conduct high-temperature corrosion test to investigate NAC behaviour of carbon steel and Cr5Mo low alloy steel at different sulphur contents and total acid numbers (TAN). The result shows that the corrosion rate of carbon steel and low alloy steel is high at low TAN and high TAN while it keeps at a low value at medium TAN. Corrosion product film on Cr5Mo low alloy steel surface is denser and more compact than that of carbon steel at high TAN. The chromium present in Cr5Mo low alloy steel plays an important role in NAC resistance by the formation of Cr₇S₈ film in the inner layer of the scale. Corrosion rates of the two steels in secondary vacuum gas oil are high at low TAN and high TAN, but low at medium TAN which are strange and different from previous experimental results conducted in non-industrial oil solution. A tentative explanation for this new phenomenon is also put forward.     

Research on corrosivity of narrow distillate oil of crude oil with naphthenic acid and sulfur

The present study is focused on corrosion of crude oil containing naphthenic acid (NA) and sulfur to provide effective anticorrosion measures for the process units of oil refineries. Corrosion laws of distillate oils from crude oil with NA and sulfur can be studied through the impact of temperature, flow velocity, sulfur content, and acid value on corrosion changes of sulfur and NA before and after the experiments.     

环烷酸和硫化腐蚀体系的热力学分析

从热力学角度讨论了环烷酸和硫化氢组成的腐蚀体系的热力学性质。结果表明：含高硫、高酸值的原油在温度小于３９８．９８Ｋ时,所形成的ＦｅＳ地环烷酸的侵蚀具有一定的保护作用,高于此温度将丧失保护作用,温度、浓度的变化不同程度的影响腐蚀产物的组成,讨论了ＦｅＳ在环烷酸中可能的溶解机理,探讨了选择成型缓蚀剂的原则。