• Plant Journal
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• v.8 no.2
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• pp.70-81
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• 2012

The study aims to supplement facility management plan and safety regulations & standard of oil pipeline by searching and reviewing related regulation & standard inside and outside of the country. Korean regulation & standard is reviewed based on harbor and fishery design standard of the ministry of maritime affairs and fisheries, general technology standard of oil pipeline safety regulation, gas excavation construction and safety maintenance indicator of Korea gas corporation. Global regulation & standard is reviewed based on U.S standard inspection for offshore pipeline and Europe/Mexico standard inspection for offshore pipeline. The contents of offshore pipeline installation is inserted into pipeline sector for objected facilities of safety inspection regulation & standard and, the standard of safety inspection for offshore pipeline is newly presented into pipeline maintenance part of the planning facilities management with its inspection period and method.

• Journal of the Korean Institute of Gas
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• v.4 no.2 s.10
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• pp.7-14
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• 2000

LNG (Liquified Natural Gas) carried by LNG ship is unloaded into the LNG storage tanks at the very low temperature (a little lower than the boiling point of LNG). Because LNG is unloaded through the pipeline, two phase flow appears in the pipeline. In this study, we have studied the pressure-drop mechanisms of the two-phase flow in the pipeline, and the calculation method of BOG (Boil-off Gas) amount based on the heat transfer mechanism through the insulation and the surface of the pipeline. We have developed a computer program for thermal-hydraulic analysis on the LNG pipeline system. We have also developed the optimal design program to find the optimal thickness of insulation and the pipeline size. The program searches the optimal design with the minimum capital cost of pipelines and insulation on the operating conditions of maximum allowance pressure-drop and BOG amount, etc.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.253-258
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• 2001

This paper introduces a simple nonlinear adaptive control method for pipeline inspection gauge (PIG) flow in natural gas pipeline. The dynamic behavior of the PIG depends on the different pressure across its body and the bypass flow through it. The system dynamics includes: dynamics of driving gas flow behind the PIG, dynamics of expelled gas in front of the PIG, and dynamics of the PIG. The method of characteristics (MOC) and Runger-Kuta method are used to solve the dynamics of flow. The PIG velocity is controlled through the amount of bypass flow across its body. A simple nonlinear adaptive controller based on the backstepping method is introduced. To derive the controller, three system parameters should be measured: the PIG position, its velocity and the velocity of bypass flow across the PIG body. The simulation has been done with a pipeline segment in the KOGAS low pressure system, Ueijungboo-Sangye line to verify the effectiveness of the proposed controller. Three cases of interest are considered: the PIG starts to move at its launcher, the PIG arrives at its receiver and the PIG restarts after stopping in the pipeline by obstruction. The simulation results show that the proposed nonlinear adaptive controller attained good performance and can be used for controlling the PIG velocity.

• Journal of Mechanical Science and Technology
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• v.17 no.9
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• pp.1349-1357
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• 2003

This paper deals with verification of the theoretical model for dynamic behavior of Pipeline Inspection Gauge (PIG) traveling through high pressure natural gas pipeline. The dynamic behavior of the PIG depends on the differential pressure across its body. This differential pressure is generated by injected gas flow behind the tail of the PIG and expelled gas flow in front of its nose. To analyze the dynamic behavior characteristics such as gas flow in pipeline, and the PIG position and velocity, not only the mathematical models are derived, but also the theoretical models must be certified by actual pigging experiment. But there is not any found results of research on the experimental certification for dynamic behavior of the PIG. The reason is why the fabrication of the PIG as well as, a field application are very difficult. In this research, the effectiveness of the introduced solution using the method of characteristics (MOC) was certified through field application. In-line inspection tool, 30" geometry PIG, was fabricated and actual pigging was carried out at the pipeline segment in Korea Gas Corporation (KOGAS) high pressure system, Incheon LT (LNG Terminal) -Namdong GS (Governor Station) line. Pigging is fulfilled successfully. Comparison of simulation results with experimental results show that the derived mathematical models and the proposed computational schemes are effective for predicting the position and velocity of the PIG with a given operational conditions of pipeline.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.1
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• pp.43-48
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• 2009

The fatigue crack growth behavior of high strength X80 pipeline steel was investigated with compact tension specimens that crack growth directions were aligned either parallel or normal to the rolling direction of the pipeline. Also, the fatigue crack growth rates for welded joint of X80 pipeline steel were investigated with compact tension specimens that crack growth directions were aligned either parallel or normal to the welding line. The experimental results indicated the fatigue crack growth behavior was markedly different in three zones, weld metal, heat affected zone and base metal of welded joints. There was a trend toward increment in the fatigue life of weld metal and heat affected zone as compared with the X80 pipeline steel.

• Journal of the Korean Institute of Gas
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• v.21 no.1
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• pp.72-79
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• 2017

The operating temperature range of the natural gas pipeline in Arctic environment would be controlled primarily to optimize gas throughput and to minimize the environmental impact resulting from operation of such pipelines. The temperature of the gas as it flows through the pipeline is a function of both the Joule-Thomson effect and the pipe to soil heat transfer. Therefore, the heat transfer and Joule-Thomson effect of the buried natural gas pipeline in this study were carefully considered. Soil temperatures and overall heat transfer coefficients were assumed to be $0{\sim}-20^{\circ}C$ and $0{\sim}5.5W/m^2K$, respectively. The gas temperature and pressure calculations along a pipeline were performed simultaneously at different soil temperatures and overall heat transfer coefficients. Also, this study predicted the phase change and hydrate formation for different soil temperatures and overall heat transfer coefficients using HYSYS simulation package.

• 한국가스학회:학술대회논문집
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• 2006.11a
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• pp.191-195
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• 2006

Because of the continuous growth of energy consumption and also the tendency to site gas pipeline and power line along the same route, the close proximity of power lines and buried metallic pipelines has become more and more frequent. The lightning strokes collected by an electric substation or power line tower might cause arcing through the soil to an adjacent gas pipeline. This paper gives the outline of the resistance coupling and the standards of distance between gas pipeline and tower ground.

• International Journal of Precision Engineering and Manufacturing
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• v.7 no.3
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• pp.24-29
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• 2006

Pressurized gas pipelines are subject to harmful effects from both the surrounding environment and the materials passing through them. Reliable assessment procedures, including fracture mechanics analyses, are required to maintain their integrity. Currently, integrity assessments are performed using conventional deterministic approaches, even though there are many uncertainties to hinder rational evaluations. Therefore, in this study, a probabilistic approach was considered for gas pipeline evaluations. The objectives were to estimate the failure probability of a corroded pipeline in the gas and oil industries and to propose limited operating conditions for different types of loadings. To achieve these objectives, a probabilistic assessment program was developed using a reliability index and simulation techniques, and applied to evaluate the failure probabilities of a corroded API-5L-X52 gas pipeline subjected to internal pressures, bending moments, and combined loadings. The results demonstrated the potential of the probabilistic integrity assessment program.

• Journal of the Korean Institute of Gas
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• v.15 no.2
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• pp.27-32
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• 2011

In this paper a new defect length estimation algorithm using SQI(self quotient image) is presented for the MFL(magnetic flux leakage) inspection of underground gas pipelines. Gas pipelines are magnetized by the permanent magnets of the MFL PIG(pipeline inspection gauge) when the PIG runs through pipelines. If defects or corrosions exist in the pipeline, magnetic leakage flux is increased. The MFL signals measured by hall sensors are analyzed to estimate defect length using SQI. For 74 real defects carved in KOGAS pipeline simulation facility(KPSF) the accuracy of defect length estimation of the proposed algorithm was compared with that of conventional methods.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.241-246
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• 2001

This paper introduces modeling and solution for the dynamics of pipeline inspection gauge (PIG) flow in natural gas pipeline. Without of bypass flow, the dynamic behavior of the PIG depends on the different pressure between the rear and nose parts, which is generated by injected gas flow behind the tail of the PIG and expelled gas flow in front of its nose. With bypass flow, the PIG dynamics also depends on the amount of bypass flow across its body. The mathematical model are derived for unsteady compressible flow of the PIG driving and expelled gas, and for dynamics of the PIG. The bypass flow is assumed to be incompressible with the condition of its Mach number smaller than 0.45. The method of characteristic (MOC) and the Runge-Kutta method are used to solve the system governing equations. The simulation is performed with a pipeline segment in the Korea Gas Corporation (KOGAS) low pressure system, Ueijungboo-Sangye line. The simulation results show that the derived mathematical model and the proposed solution are effective for estimation the dynamics of the PIG with and without bypass flow under given operational condition.