催化装置油气分离器环焊缝断口分析
发布时间：2018-11-03 16:56
【摘要】：某石化公司催化装置气压机出口油气分离器R1341为二类卧式压力容器,1974年12月设计,1984年10月随装置开工投入运行。2008年12月,油气分离器R1341在运行中发现筒体环焊缝下部位置出现2条横向裂纹,采用铁胶泥铆固方案进行了处理。之后一个月内该容器环缝又出现6处横向裂纹,均用前述方案进行处理。2009年2月中旬,催化装置停工消缺,油气分离器R1341停运更新。在开裂环焊缝上切取含有二条裂纹(间距450mm)的部分,切700mm×400mm壁板一块作为油气分离器试验分析样品,分别在样品壁板的焊缝、母材部位取相应试件进行宏观检查、化学成份、金相观察、硬度测试、拉伸、冲击试验、断口形貌观察、微区EDS分析等理化分析。化学成份分析结果表明,筒体钢板和焊缝金属中均具有较高的S、P含量,能谱分析结果也证实了裂纹缝隙中确实有MnS夹杂物的存在。由此可见,在湿硫化氢环境中该设备筒体钢板和焊缝发生HIC是不可避免的。近年来该石化公司加工的高含硫原油数量不断增加,导致油气分离器R1341工艺介质中H2S浓度不断上升,随着介质中硫化氢含量的提升,反应产生的H离子数目显著增多,氢离子附着到容器表面转换为氢原子并扩散到钢材质中。接下来,这些氢原子首先聚集在金属的焊缝及容器原材料的工艺缺陷(特别是硫化锰杂质)处合成氢分子,氢原子化合成为氢分子后,最终引起了该处氢致开裂(HIC)现象的发生。该石化公司生产装置原设计为低硫原油,材质等级较低。从84年开工至2005年,一直加工低硫原油,设备运行基本正常。2006年以来,随着加工原油硫含量不断升高,设备腐蚀明显加剧,设备现状与实际工况出现明显的不适应。油气分离器R1341原设计材质为16MnR,未进行热处理,无法满足长期在湿硫化氢环境下运行的要求。根据以上分析结果,结合该企业生产实践具体情况,提出以下技术改造建议。1湿硫化氢环境用设备应该更加注意设备母材的选择,如耐硫化氢腐蚀的材料;2在设备设计制造时,选择更优化的工艺,有效降低材料焊缝中金属硫和磷元素的含量。生产设备整体热处理,降低焊缝硬度。3设备的内部全面防腐蚀处理,进一步提升设备的抗腐蚀能力;4在根源上控制腐蚀的产生,从工艺设计,设备制造,生产流程全面重视防腐蚀问题,重视工艺注水、注剂的管理。
[Abstract]:The outlet oil and gas separator R1341 of a catalytic unit of a petrochemical company is a kind of horizontal pressure vessel. It was designed in December 1974 and put into operation with the unit in October 1984. In December 2008, the oil and gas separator R1341 is a kind of horizontal pressure vessel. In operation of oil and gas separator R1341, two transverse cracks were found in the lower part of the tube girth weld, which was treated by iron cement riveting scheme. In the following month, six more transverse cracks appeared in the circumferential crack of the vessel, all of which were treated with the aforementioned scheme. In mid February 2009, the catalytic unit was shut down and the oil and gas separator R1341 was replaced. The part containing two cracks (spacing 450mm) was cut on the crack girth weld, and a piece of 700mm 脳 400mm wall plate was cut as the sample for the oil and gas separator test and analysis. The samples were taken from the weld seam and the base metal part of the sample wall respectively for macroscopic inspection and chemical composition. Metallographic observation, hardness test, tensile test, impact test, fracture morphology observation, microzone EDS analysis and other physicochemical analysis. The results of chemical composition analysis show that there is a high content of MnS in steel plate and weld metal, and the existence of MnS inclusions in cracks is confirmed by energy spectrum analysis. It can be seen that HIC is inevitable in the wet hydrogen sulfide environment. In recent years, the quantity of high-sulfur crude oil processed by the petrochemical company has been increasing, resulting in the increasing concentration of H _ 2S in the medium of R1341 process. With the increase of hydrogen sulfide content in the medium, the number of H ~ (2 +) produced by the reaction increases significantly. Hydrogen ions are attached to the surface of the vessel and converted into hydrogen atoms and diffused into steel. Next, these hydrogen atoms first gather in the weld of the metal and at the defects of the raw materials of the container (especially manganese sulphide impurity) to synthesize hydrogen molecules, and after the hydrogen atoms combine to form hydrogen molecules, Finally, the (HIC) phenomenon of hydrogen induced cracking occurred. The production unit of the petrochemical company was originally designed for low sulfur crude oil, and its material grade is lower. Starting from 1984 to 2005, the equipment has been processing low sulfur crude oil, and the equipment operation is basically normal. Since 2006, with the increasing sulfur content of processed crude oil, the corrosion of the equipment has become more and more serious, and the present situation of the equipment is obviously unsuitable to the actual working conditions. The original design material of oil and gas separator R1341 is 16MnR, without heat treatment, it can not meet the requirements of running under wet hydrogen sulfide environment for a long time. According to the above analysis results, combined with the concrete situation of production practice in this enterprise, the following suggestions are put forward. 1 the selection of equipment base materials, such as materials resistant to corrosion of hydrogen sulfide, should be paid more attention to for wet hydrogen sulfide environment equipment; (2) when the equipment is designed and manufactured, the content of metal sulfur and phosphorus in the weld metal can be effectively reduced by selecting more optimized process. The whole heat treatment of the production equipment reduces the weld hardness. 3 the internal corrosion prevention treatment of the equipment further improves the anticorrosion ability of the equipment; (4) to control the origin of corrosion, from the aspects of process design, equipment manufacture and production process, to pay attention to corrosion prevention, process water injection and the management of injection agent.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE96
本文编号：2308383
[Abstract]:The outlet oil and gas separator R1341 of a catalytic unit of a petrochemical company is a kind of horizontal pressure vessel. It was designed in December 1974 and put into operation with the unit in October 1984. In December 2008, the oil and gas separator R1341 is a kind of horizontal pressure vessel. In operation of oil and gas separator R1341, two transverse cracks were found in the lower part of the tube girth weld, which was treated by iron cement riveting scheme. In the following month, six more transverse cracks appeared in the circumferential crack of the vessel, all of which were treated with the aforementioned scheme. In mid February 2009, the catalytic unit was shut down and the oil and gas separator R1341 was replaced. The part containing two cracks (spacing 450mm) was cut on the crack girth weld, and a piece of 700mm 脳 400mm wall plate was cut as the sample for the oil and gas separator test and analysis. The samples were taken from the weld seam and the base metal part of the sample wall respectively for macroscopic inspection and chemical composition. Metallographic observation, hardness test, tensile test, impact test, fracture morphology observation, microzone EDS analysis and other physicochemical analysis. The results of chemical composition analysis show that there is a high content of MnS in steel plate and weld metal, and the existence of MnS inclusions in cracks is confirmed by energy spectrum analysis. It can be seen that HIC is inevitable in the wet hydrogen sulfide environment. In recent years, the quantity of high-sulfur crude oil processed by the petrochemical company has been increasing, resulting in the increasing concentration of H _ 2S in the medium of R1341 process. With the increase of hydrogen sulfide content in the medium, the number of H ~ (2 +) produced by the reaction increases significantly. Hydrogen ions are attached to the surface of the vessel and converted into hydrogen atoms and diffused into steel. Next, these hydrogen atoms first gather in the weld of the metal and at the defects of the raw materials of the container (especially manganese sulphide impurity) to synthesize hydrogen molecules, and after the hydrogen atoms combine to form hydrogen molecules, Finally, the (HIC) phenomenon of hydrogen induced cracking occurred. The production unit of the petrochemical company was originally designed for low sulfur crude oil, and its material grade is lower. Starting from 1984 to 2005, the equipment has been processing low sulfur crude oil, and the equipment operation is basically normal. Since 2006, with the increasing sulfur content of processed crude oil, the corrosion of the equipment has become more and more serious, and the present situation of the equipment is obviously unsuitable to the actual working conditions. The original design material of oil and gas separator R1341 is 16MnR, without heat treatment, it can not meet the requirements of running under wet hydrogen sulfide environment for a long time. According to the above analysis results, combined with the concrete situation of production practice in this enterprise, the following suggestions are put forward. 1 the selection of equipment base materials, such as materials resistant to corrosion of hydrogen sulfide, should be paid more attention to for wet hydrogen sulfide environment equipment; (2) when the equipment is designed and manufactured, the content of metal sulfur and phosphorus in the weld metal can be effectively reduced by selecting more optimized process. The whole heat treatment of the production equipment reduces the weld hardness. 3 the internal corrosion prevention treatment of the equipment further improves the anticorrosion ability of the equipment; (4) to control the origin of corrosion, from the aspects of process design, equipment manufacture and production process, to pay attention to corrosion prevention, process water injection and the management of injection agent.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE96
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