• Journal of Advanced Research in Ocean Engineering
• /
• 제2권4호
• /
• pp.158-168
• /
• 2016

During the installation of crude oil or gas pipelines, which pass through onshore buried pipelines or onshore pipeline from subsea pipeline to onshore plant, countermeasures need to be implemented so as to ensure a sufficient design life by protecting the steel pipes against corrosion. This can be achieved through impressed current cathodic protection method for onshore pipelines and through galvanic sacrificial anode corrosion protection method for offshore pipelines. In particular, in the case of impressed current cathodic protection, isolation joint flanges should be used. However, this makes maintenance control difficult with its installation having a negative impact on price. Therefore, in this study, the most suitable methodology for onshore pipeline protection between galvanic sacrificial anode corrosion protection and impressed current cathodic protection method will be introduced. In oil and gas transportation facilities, the media can be carried to the end users via onshore buried and/or offshore pipeline. It is imperative for the field operators, pipeline engineers, and designers to be corrosion conscious as the pipelines would undergo material degradations due to corrosion. The mitigation can be achieved with the introduction of an impressed current cathodic protection method for onshore buried pipelines and a galvanic sacrificial anode corrosion protection method for offshore pipelines. In the case of impressed current cathodic protection, isolation joint flanges should be used to discontinuity. However, this makes maintenance control to be difficult when its installation has a negative impact on the price. In this study, the most suitable corrosion protection technique between galvanic sacrificial anode corrosion protection and impressed current cathodic protection is introduced for (economic life of) onshore buried pipeline.

• 한국안전학회지
• /
• 제13권2호
• /
• pp.54-64
• /
• 1998

This study was initiated to examine the stress and deformation characteristics of the pipelines which were subjected to various environmental conditions in order to confirm their integrity. As the part of them, this paper presents the analysis results for the effect of ground subsidence combined with main loads on buried natural gas pipelines. The ground subsidence which can occur for buried gas pipeline has been classified to the three cases. Finite element method was used to analyze the effect of ground subsidences on pipeline of 26 inch(0.660 m) and 30 inch(0.762 m) diameter used as high pressure ($70 kg_f/cm^2(6.86 MPa)$) main pipelines of KOGAS. This paper shows the result of stress analysis for the pipelines subjected to those three case ground subsidence. Comparing these results with safety criterion of KOGAS(0.9 $\sigma_y$), maximum allowable settlement and loads have been calculated.

• Earthquakes and Structures
• /
• 제26권3호
• /
• pp.239-249
• /
• 2024

A new layered shear continuum model box was developed to address the dynamic response issues of buried oil and gas pipelines under multi-point excitation. Vibration table tests were conducted to investigate the seismic response of buried pipelines and the surrounding soil under longitudinal multi-point excitation. A nonlinear model of the pipeline-soil interaction was established using ABAQUS finite element software for simulation and analysis. The seismic response characteristics of the pipeline and soil under longitudinal multi-point excitation were clarified through vibration table tests and simulation. The results showed good consistency between the simulation and tests. The acceleration of the soil and pipeline exhibited amplification effects at loading levels of 0.1 g and 0.2 g, which significantly reduced at loading levels of 0.4 g and 0.62 g. The peak acceleration increased with increasing loading levels, and the peak frequency was in the low-frequency range of 0 Hz to 10 Hz. The amplitude in the frequency range of 10 Hz to 50 Hz showed a significant decreasing trend. The displacement peak curve of the soil increased with the loading level, and the nonlinearity of the soil resulted in a slower growth rate of displacement. The strain curve of the pipeline exhibited a parabolic shape, with the strain in the middle of the pipeline about 3 to 3.5 times larger than that on both sides. This study provides an effective theoretical basis and test basis for improving the seismic resistance of buried oil and gas pipelines.

• 한국농공학회지
• /
• 제41권6호
• /
• pp.64-74
• /
• 1999

The frequency of earthquake occurrence tends to increase in Korea. Therefore, the stability of pipeline, such as watersupply pipe, gas pipe, and oil pipe etc. across fault zones in Gyoung-sang landmass is very important, expecially , in metropolitan area. There were some examples of the construction of buried pipeline across fault zones in Korea. the interactiion between the buried pipeline across fault zones and the ground is considered. As well, in the interfaces of them, the direct shear numerical analysis model including elasto-plastic joint element is assumed that the retained dilatancy theory in them, otherwise. Also, the other elements are modeled the ground is nonlinear elastic coutinuaus beam, respectively. In this study, the maximum shear force point exist inside retaine zone(anchored zone) during shwar (as fault sliding), and the distribution of pipeline's behavior is all alike them of pipeline buried in ladnsliding grounds. Since the pipeline is not continuous beam but jointed by steel-pipe segments , practically, on acting of a large bending moment or a shear force, then, those are may be unstable. The reaearch on this point may be new approach.

• 한국가스학회지
• /
• 제22권3호
• /
• pp.53-64
• /
• 2018

천연가스는 폭발성 유체로 고압의 매설 배관 파손시 심각한 인적/물적 손해를 야기할 수 있으며, 최근에도 실제 매설 배관의 파손으로 상당한 인명피해가 발생한 사례가 보고되고 있다. 국내의 경우, 급속한 성장 및 보급에도 불구하고 천연가스 배관의 운영 길이와 운영기간이 짧아 가스배관의 사고원인 등에 대한 유효한 사고데이터의 확립이 부족한 실정이다. 국내에서 사고 사례에 대한 데이터베이스를 체계적으로 구축하기 위하여 국내보다 천연가스 배관의 운용 역사가 길고, 긴 배관망을 갖고 있는 해외 주요국에서 발생한 최근의 천연가스 배관관련 사고의 원인과 빈도를 분석하는 것이 필요하다. 따라서 본 연구에서는 해외 주요국에서 가스배관의 사고원인별 발생 빈도의 추이를 파악한 후 이를 비교 분석하여 국내 고압가스 운송 배관망의 안정성 확보의 토대를 구축하고자 하였다.

• 한국가스학회지
• /
• 제4권2호
• /
• pp.37-45
• /
• 2000

지하에 매설되어 있는 도시가스배관은 부식성 없는 유체이기 때문에 화학플랜트배관보다는 상대적으로 안전하다. 그러나, 도시가스는 일반적으로 도심지역에 공급됨으로 공급지역의 여러 간섭시설물과 환경에 의한 부식과 시설물의 굴착공사로 야기되는 제 3자 사고등으로 큰 사고를 야기할 수 있다. 특히 지하매설된 배관이므로, 배관의 손상여부를 파악하고 검사하는 것이 상당히 난해하다. 따라서, 본 고에서는 지하매설배관의 위험성 개념을 도입하여, 위험지역 배관을 선정하여 관리하는 것으로 접근하였다. 여기서 위험성은 부식요인, 설계 및 시공요인, 유지관리요인으로 파악하여 나타내었고, 배관의 정성적인 위험성을 점수로 표현하여, 정량적인 숫자로 표현하였다. 또한 Key 인자 개념과 비용에 대한 손상보완대책 개념을 프로그램에 도입하여, 신뢰성과 안전경영에 도움이 되리라 생각된다. 본 위험성 평가 프로그램은 비쥬얼 베이직을 사용하여 개발하였고, GIS와 연계하였다.

• Corrosion Science and Technology
• /
• 제2권3호
• /
• pp.161-163
• /
• 2003

With the development of Chinese petroleum and gas industry, about 20,000 km long-distance pipeline and 250,000 km gathering pipeline have been constructed in China. After operating for many years, most of the coatings on buried pipelines have aged so severe that the steel pipes are subject to corrosion environment underground. Focusing on the need of external coating for buried pipeline rehabilitation, a new type of coating has been developed. The development and application of the coatings has been introduced in this paper.

• 대한기계학회논문집A
• /
• 제36권10호
• /
• pp.1131-1137
• /
• 2012

해저배관은 부력과 외부 충격을 방지하기 위하여 1.2~4m의 매설 깊이로 설치되어 운영된다. 해저배관은 수압과 토하중에 의한 외압으로부터 소성붕괴에 대한 저항성을 가져야한다. 해저배관에 수압과 토하중으로 발생하는 원주응력을 유한요소해석으로 파악하여 배관의 건전성에 미치는 영향을 평가하였다. 내압은 외압에 의한 소성붕괴 저항성을 향상시켜 소성붕괴 발생 깊이를 증가시켰다 동일 수심에서는 매설 깊이 증가에 따라 원주응력은 증가하나, 동일 매설 깊이에서는 수심이 증가함에 따라 배관에서 발생하는 원주응력은 감소한다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 A
• /
• pp.346-348
• /
• 2001

This paper analyze the interference problems, especially AC corrosion when the gas pipeline is buried with power cable in the same submarine tunnel. This paper present the results of the study about AC corrosion, limitation of safety voltage, modeling of power cables, gas pipeline and grounding systems, analysis of induction voltage according to various circumstance, soil resistivity, length of tunnel. and so on.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제49권10호
• /
• pp.577-582
• /
• 2000

This paper analyze the interference problems, especially Ac corrosion when the gas pipeline is buried with power cable in the same submarine tunnel. This paper present the results of the study about interference mechanism(inductive coupling, conductive coupling, resistive coupling), AC corrosion, limitation of safety voltage, modeling of power cables, gas pipeline and grounding systems, analysis of induction voltage and optimal arrangement of power cables.