Put geosynthetic clay liners around underground oil-gas pipelines can reduce the potential damage to environment but it will also affect the distribution of cathodic protection current. Geosynthetic clay liners can be...Put geosynthetic clay liners around underground oil-gas pipelines can reduce the potential damage to environment but it will also affect the distribution of cathodic protection current. Geosynthetic clay liners can be regarded as anisotropic soil structure and the potential distribution on the pipeline between two adjacent cathodic protection stations was calculated based on boundary element method (BEM). The calculation results indicate that potential distribution on the pipeline with geosynthetic clay liner is lower than before. A 1500 m built pipeline with geosynthetic clay liners was selected to be calculated and to perform field test, which shows that the calculation results tally well with the field test results and the validity of the arithmetic in this paper was verified.展开更多
Pipeline is a key segment in the transportation of city gas and its safety affec ts the safety of industrial and domestic application. The characteristics of Shi Dongkou east gas steel pipeline buried in soil were dis...Pipeline is a key segment in the transportation of city gas and its safety affec ts the safety of industrial and domestic application. The characteristics of Shi Dongkou east gas steel pipeline buried in soil were discussed and its parameters related to safety were measured, including the state of anticorrosiv e layer, the soil resistivity, the natural potential and the protective potential of gas pipeline. The experimental result s were confirmed by excavating, which are of value to the knowledge of the gas pipeline buried in soil in Shanghai. The experimental data were analyzed which provide the scientific basis for the assurance of the gas pipeline safety and the reparation of anticorrosivelayer.展开更多
The industrial application of an exterior three-layer anticorrosive polypropylene coating system(3PP)on large-diameter(larger than Φ600 mm)steel pipes was developed using an experimental process simulation study and ...The industrial application of an exterior three-layer anticorrosive polypropylene coating system(3PP)on large-diameter(larger than Φ600 mm)steel pipes was developed using an experimental process simulation study and the optimization of raw materials inspection,steel pipe surface pretreatments,and water cooling control on a coating application process.The coating properties meet ISO standard 21809 on buried or submerged 3PP pipelines used in the petroleum and natural gas industries.Differential scanning calorimetry and X-ray diffraction were used to analyze the crystallinities and grain sizes of polypropylene(PP)top coats with different cooling rates.Increasing the melt cooling rate reduces the crystallinity and grain size of the PP top coat and enhances its strength and toughness.展开更多
A rectangle crevice assembly was used to study the effects of cathodic protection （CP） potential, crevice thickness, holiday size, bubbling CO2, and surface condition on the chemical and electrochemical environment ...A rectangle crevice assembly was used to study the effects of cathodic protection （CP） potential, crevice thickness, holiday size, bubbling CO2, and surface condition on the chemical and electrochemical environment of the local solution under disbonded coatings. It is found that the cathodic protection removes dissolved oxygen from the crevice and thus shifts the solution to a more al- kaline state. Furthermore, the potential of the steel reaches the protected potential range. The available protection distance increases with the negative applying potential. The steady potential and pH distribution are easily achieved, but the polarization degree is not satisfied within the thinner crevice. The difference in the solution environment is found to correlate to the holiday size. The smaller the holiday, the smaller the difference is. The presence of CO2 inhibits the formation of an alkaline environment. It is also found that the rust layer dramatically decreases the polarization rate in the crevice.展开更多
This paper presents the detail design conditions, design criteria and methods as well as design conclusions of the process, structure and corrosion of the production flowlines and high pressure water injection lines i...This paper presents the detail design conditions, design criteria and methods as well as design conclusions of the process, structure and corrosion of the production flowlines and high pressure water injection lines in BZ34-2 / 4 oil field in Bohai Bay. At present this design represents the design capability and level in the field of the submarine pipeline engineering of China.展开更多
文摘Put geosynthetic clay liners around underground oil-gas pipelines can reduce the potential damage to environment but it will also affect the distribution of cathodic protection current. Geosynthetic clay liners can be regarded as anisotropic soil structure and the potential distribution on the pipeline between two adjacent cathodic protection stations was calculated based on boundary element method (BEM). The calculation results indicate that potential distribution on the pipeline with geosynthetic clay liner is lower than before. A 1500 m built pipeline with geosynthetic clay liners was selected to be calculated and to perform field test, which shows that the calculation results tally well with the field test results and the validity of the arithmetic in this paper was verified.
文摘Pipeline is a key segment in the transportation of city gas and its safety affec ts the safety of industrial and domestic application. The characteristics of Shi Dongkou east gas steel pipeline buried in soil were discussed and its parameters related to safety were measured, including the state of anticorrosiv e layer, the soil resistivity, the natural potential and the protective potential of gas pipeline. The experimental result s were confirmed by excavating, which are of value to the knowledge of the gas pipeline buried in soil in Shanghai. The experimental data were analyzed which provide the scientific basis for the assurance of the gas pipeline safety and the reparation of anticorrosivelayer.
文摘The industrial application of an exterior three-layer anticorrosive polypropylene coating system(3PP)on large-diameter(larger than Φ600 mm)steel pipes was developed using an experimental process simulation study and the optimization of raw materials inspection,steel pipe surface pretreatments,and water cooling control on a coating application process.The coating properties meet ISO standard 21809 on buried or submerged 3PP pipelines used in the petroleum and natural gas industries.Differential scanning calorimetry and X-ray diffraction were used to analyze the crystallinities and grain sizes of polypropylene(PP)top coats with different cooling rates.Increasing the melt cooling rate reduces the crystallinity and grain size of the PP top coat and enhances its strength and toughness.
基金supported by the National Science & Technology Infrastructure Development Program of China (No.2005DKA10400)
文摘A rectangle crevice assembly was used to study the effects of cathodic protection （CP） potential, crevice thickness, holiday size, bubbling CO2, and surface condition on the chemical and electrochemical environment of the local solution under disbonded coatings. It is found that the cathodic protection removes dissolved oxygen from the crevice and thus shifts the solution to a more al- kaline state. Furthermore, the potential of the steel reaches the protected potential range. The available protection distance increases with the negative applying potential. The steady potential and pH distribution are easily achieved, but the polarization degree is not satisfied within the thinner crevice. The difference in the solution environment is found to correlate to the holiday size. The smaller the holiday, the smaller the difference is. The presence of CO2 inhibits the formation of an alkaline environment. It is also found that the rust layer dramatically decreases the polarization rate in the crevice.
文摘This paper presents the detail design conditions, design criteria and methods as well as design conclusions of the process, structure and corrosion of the production flowlines and high pressure water injection lines in BZ34-2 / 4 oil field in Bohai Bay. At present this design represents the design capability and level in the field of the submarine pipeline engineering of China.
