Qiqi Feng Xiaomei et al .: Pressure test requirements for trunk pipelines in undulating areas, oil and gas storage and transportation, 2000, 19 (6) 2122. Due to changes in position difference, the requirements of ordinary test pipelines cannot be copied in terms of pressure test strength values. Introduced the work of the pressure test of the Kushan pipeline according to three requirements: â‘ divide the pressure test section according to the spacing of the pipeline interception valves, instead of taking the inter-station and overall pressure test; % X-ray inspection to improve safety; â‘¢ Use water as the pressure test medium to find defects such as pinholes of the girth weld in time.
The main word of the pipeline topography fluctuation pressure test requirements 1. The value of the pipeline strength pressure test. The purpose of the pipeline trunk line ball sweeping and pressure test is to clean up the debris in the lumen and eliminate the hidden dangers and defects of the pipeline to ensure pipeline oil transportation. For the safety of operation, its engineering volume accounts for about a quarter of the entire pipeline trunk project.
At present, the values ​​of pipeline strength test pressures of some large foreign oil companies are roughly as follows.
Take the minimum yield pressure of the material with the strength test pressure of 90% -volume graph to control the strength test pressure. When the graph shows nonlinearity, stop the pressure increase.
The strength test pressure of pipelines in China is 1.5 times of the operating pressure. The operating pressure is in accordance with GB50253-94 standard. 072 is taken outside the oil station and 060 is taken inside the oil station. In fact, some large foreign oil companies test the strength of the long pipeline There is no hard and fast rule, but the owner and the contractor jointly agree on the pressure test level. There should be greater flexibility in complex mountainous terrain and large drop areas. For example, the Xinjiang Kuzhu oil pipeline is the pipeline with the largest drop in China at present. The length of the large drop area is 112km and the gap is 1620m. In order to reduce the wall thickness at the low point of the pipeline, A decompression station is set at the midpoint of the large drop zone. The steel pipe with a total length of 475 = 448MPa is divided into 6 'grade wall thickness (7.111.1mm), the wall thickness of each grade differs by 0.8mm, the pipe diameter is 610mm, and the outlet pressure of the first station oil pump is 8.0MPa. t, in the end, the middle chestnut station is not pressurized. The pipeline was designed by the Italian company Snamprogetti, and the following pipeline pressure strength test pressure conditions were proposed for the pipeline characteristics.
The strength test pressure of each point of the pipeline shall not be lower than the working pressure of the pipe oil delivery at the point 1. According to the above strength conditions, the strength test pressure is carried out in sections with the interval of the main valve. During the subsequent automatic commissioning of the whole line, due to the sudden shutdown of the decompression station, a strong water hammer occurred in the upstream of the pipeline. Although some equipment and valve piers of the decompression station were damaged, the entire pipeline was intact and was still in operation. Withstood the test of more frequent intermittent transportation.
According to the experience of pipeline construction in Xinjiang in recent years, the pressure test of pipelines in arid and water-scarce areas and large drop areas in mountain areas should be carried out as follows.
(1) The pressure test of the large-drop area in the mountainous area cannot be carried out in full accordance with China's current specifications, such as the SY / T4062-93 "Pipe section test pressure length km is appropriate, the difference should not exceed 30m". Otherwise, the pressure test will be carried out in the mountainous area with large drop. If there are too many sections, it will bring more hidden danger to the pipeline. The pressure test of pipelines in large mountain areas in mountainous areas should refer to foreign experience, and consult with the design unit, and try to divide the pressure test sections according to the spacing of the pipeline interception valves. The principle of sectioning is that the hoop stress A generally caused by the water pressure is not less than 9 (2) After the section pressure test in the mountainous area with large drop, it is not appropriate to take inter-station and overall pressure test The girth welds should be 100% X-ray inspected.
The advantage of not adopting inter-station and overall pressure test is that the use of staged pressure test reduces the probability of defects or leaks in each small section, thus reducing the number of repeated pressure tests and greatly reducing the reversal of pressure bearing capacity. The reason for this is that the subcritical expansion curve of the same type of pipe is not a fixed value due to the inherent quality of the pipe and the weld. After multiple cycles of boosting and depressurizing, the pipeline has an impact on non-penetrating cracks, see.
In Figure 1, the effect of multiple cycles on non-penetrating cracks is the original crack depth. During the first cycle, a subcritical expansion curve appears and the crack depth increases to 4. If unloaded at this time, the crack depth Increase again. In the second cycle, the crack depth becomes' + name, and when the subcritical expansion curve appears again, the crack depth increment becomes the center. In the third cycle, the crack depth becomes' + name + 4. If the subcritical expansion curve appears again, the depth becomes 4. With the further increase of the pressure P. At this time, if the instability expansion curve appears , The pipeline is damaged. At this time, the total crack depth is' + 4 + 4 + 4, and the subcritical expansion is as follows. The last pressure is lower than the previous two. The difference is AP, and A is the reversal value of pressure capacity. The US WSI / ASMEB31.4 stipulates that after the pipeline pressure test is carried out in sections, and after 100% radiographic inspection of the girth weld at the dead end, there is no need to conduct an overall pressure test. The purpose of this regulation is to reduce repeated boost and depressurization cycles, thereby avoiding the reversal of pressure-bearing capacity. For intermittent transmission pipelines, the reversal of pressure bearing capacity should also be considered.
The gas pressure should not be used for the strength test of long-distance pipelines.
Because the pressure test gas stores a large amount of energy, it will expand rapidly at the rupture of the pipeline to form a shock wave. The rapidly escaping gas reduces the humidity of the rupture and causes the expansion of the steel. The speed of the pipe wall rupture extending to both sides is greater than the speed of the gas medium leakage and pressure reduction, and the length of the pipeline cracking reaches several kilometers or tens of kilometers, which is easy to cause personal injury and death. At the same time, the pressure test is not easy to find the needle of the ring weld Hole defects. With water as the medium for pressure test, the maximum crack length of the pipeline is below 3.5m, which is much lower than the pipeline crack length during the air pressure test.
Therefore, ANSI / ASMEB 31.8 (1979) clearly stipulates that when the hoop pressure caused by the operating pressure is greater than 0.2 times the yield limit of the pipe and the test pressure reaches 1.2 times the design pressure, the strength test must be conducted with water as the medium.
When preparing the overall construction plan before the pipeline project is started, the characteristics of the pipeline in the large drop zone should be combined, the plan of pipeline sweeping and pressure test in the future should be considered, and the water source, power supply, pump and valve of the proposed pump station should be used as much as possible. The advantage of this is that it is easy to grasp the main contradictions of the project construction, and organically and closely integrate the pipeline construction, pipeline pressure test, pump station process equipment, storage tank construction, and joint trial operation. Proceed in an orderly manner to achieve the purpose of shortening the construction period and reducing costs.
Editor: Liu Chunyang Li Guangqun Yuan Tongming Li Jiang Xu Baoxing Yong Qiwei Li Jingli Qi Xiaxin Hong Jianyong Zhang Fushengjing strengthened Dong Xuewang Tian Shuankui Zhang Weichang Wang Meng Hu Jianhua Chen Jiangbo Huang Qilu Liu Zhongyong Zhao Jianxin Assistant Engineer, born in 1972, graduated from Petroleum University (Shandong) major in petroleum storage and transportation in July 1996, now The process room of China National Petroleum Pipeline Engineering Co., Ltd. is engaged in design work.
An engineer, born in 1968, graduated from the Department of Chemical Engineering, Jiangsu Institute of Chemical Technology, majoring in petroleum storage and transportation in 1991. He is currently the director of the storage and transportation system office of Maoming Petrochemical Design Institute of China Petrochemical Corporation.
An engineer, born in 1971, graduated from Fushun Petroleum Institute in 1989 with a major in petroleum storage and transportation, and now works in the first station of Korla, Kushan Oil Transmission Management Department of China National Petroleum Pipeline Company.
Senior engineer, born in 1940, graduated from the Refining Department of Xi'an Petroleum Institute in 1963, and is currently the deputy chief engineer of Sinopec Group Pipeline Storage and Transportation Company.
Lecturer, born in 1967, graduated from the PLA Logistics Engineering College with a master's degree in petroleum storage and transportation in 1992. Now the PLA Logistics Engineering College is engaged in teaching and scientific research in pipeline transportation technology and technology.
PhD student, born in 1971, graduated from the Department of Chemistry and Chemical Engineering of Baoji University of Arts and Sciences in 1993, received a master's degree from the Department of Chemical Engineering of Taiyuan University of Technology in 1996, and is now pursuing a doctorate degree in the Department of Surface Science and Corrosion Engineering, University of Science and Technology Beijing.
An engineer, born in 1952, graduated from the former China Petroleum and Natural Gas Pipeline Workers College in 1985 with a major in line engineering. He is currently the deputy manager and chief engineer of the Kuan Oil Transmission Management Department of the Northwest Petroleum Pipeline Construction Command.
Engineer, born in 1969, graduated from the Department of Petroleum Exploration Instruments and Automation of Xi'an Petroleum Institute in 1991, majoring in industrial electrical automation. Now he is studying for a master's degree in the Department of Mechanical Engineering of Tsinghua University.
Engineer, born in 1970, graduated from the Development Department of Petroleum University (Shandong) in 1992, graduated from the Department of Petroleum Engineering of Petroleum University (Beijing) in 1995 with a master's degree in engineering Additive application research.
An engineer, born in 1966, graduated from the Graduate Department of the Academy of Petroleum Exploration and Development in 1992 with a master's degree in oilfield chemistry.
Now the Institute of Oil Field Chemistry of the Academy of Petroleum Exploration and Development is engaged in the research of crude oil dewaxing agent and pour point depressant.
PhD, born in 1964, graduated from the Southwest Petroleum Institute in 1999 with a doctorate degree in oil and gas engineering. Now he is mainly engaged in teaching and scientific research of oil and gas gathering and transportation technology and theory.
An engineer, born in 1962, graduated from Tianjin Building Materials Workers College in 1988 with a major in silicate technology. Now he is engaged in the research of pipeline anti-corrosion and thermal insulation technology at China National Petroleum Corporation Engineering Technology Research Institute.
An engineer, born in 1969, graduated from the Southwest Petroleum Institute of Mechanical Engineering in 1992, majoring in mining machinery. Now he is engaged in oilfield surface engineering design and scientific research at the Design Institute of Dagang Oilfield Group Company.
Engineer, born in 1964, graduated from North China Institute of Water Conservancy and Hydropower in 1985, majoring in power equipment. Now he is engaged in engineering management in the Construction Department of China Aviation Oil Xinjiang Company.
An engineer, born in 1957, graduated from the former China National Petroleum Pipeline Workers College in 1985 with a major in instrumentation automation, and now works for the Sinopec Storage and Transportation Company Xiangfan Oil Transportation Company.
Senior lecturer, born in 1960, graduated from Heilongjiang Business School in 1982 with a major in petroleum storage and transportation. He is currently the director of the Experimental Center of Zhoushan Petrochemical School (Provincial and Ministry-level Key Technical Secondary School) of Sinopec Storage Corp.
Associate Professor, born in 1942, graduated from the Department of Aircraft, Northwestern Polytechnical University in 1965. He was engaged in wind tunnel design and research at the China Aerodynamics Research and Development Center. Now he is engaged in teaching and scientific research at the PLA Logistics Engineering College.
An engineer, born in 1967, graduated from the Petroleum University (Shandong) in 1992 with a major in petroleum storage and transportation. Now he is engaged in pipeline management for the Sinopec Group Pipeline Storage and Transportation Company Xinxiang Oil Transportation Company.
An engineer, born in 1964, graduated from Petroleum Correspondence University in 1990 with a major in storage and transportation. He is currently the director of the design, analysis and testing center of Sinopec Group Pipeline Storage and Transportation Company. He is engaged in energy conservation monitoring, measurement verification, environmental monitoring, and oil product testing.
Pet Feeder are more and more favored by people who like to keep pets. Nowadays, many people like to keep small pets, but for office workers, most of the time is spent on work every day. It is difficult for office workers to squeeze out a fixed time to feed their pets, which is also a source of distress for them. With a Pet
Feeding Kit, there is no need to worry about their beloved pets running out of food when they go out.
Pet Feeder,Pet Feeding Kit,Pet Medicine Feeder,Pet Feeding Spoon
Mianyang Crossing Cross-Border E-Commerce Co., Ltd. , https://www.wycypets.com