• 한국가스학회:학술대회논문집
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• 한국가스학회 2003년도 춘계학술발표회 논문집
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• pp.193-196
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• 2003

• Journal of Mechanical Science and Technology
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• 제15권8호
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• pp.1165-1173
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• 2001

This paper deals with dynamic analysis of Pipeline Inspection Gauge (PIG) flow control in natural gas pipelines. The dynamic behaviour of PIG depends on the pressure differential generated by injected gas flow behind the tail of the PIG and expelled gas flow in front of its nose. To analyze dynamic behaviour characteristics (e.g. gas flow, the PIG position and velocity) mathematical models are derived. Tow types of nonlinear hyperbolic partial differential equations are developed for unsteady flow analysis of the PIG driving and expelled gas. Also, a non-homogeneous differential equation for dynamic analysis of the PIG is given. The nonlinear equations are solved by method of characteristics (MOC) with a regular rectangular grid under appropriate initial and boundary conditions. Runge-Kutta method is used for solving the steady flow equations to get the initial flow values and for solving the dynamic equation of the PIG. The upstream and downstream regions are divided into a number of elements of equal length. The sampling time and distance are chosen under Courant-Friedrich-Lewy (CFL) restriction. 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 models and the proposed computational scheme are effective for estimating the position and velocity of the PIG with a given operational condition of pipeline.

• 한국지하수토양환경학회지:지하수토양환경
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• 제6권3호
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• pp.43-52
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• 2001

쓰레기 매립지에 개설된 수많은 포집정으로부터 매립가스를 포집하여 연결된 배관망을 통해 처리계통까지 지속적이고 안정적으로 수송시키는 일은 매우 중요하다. 이러한 매립가스의 안정적인 포집 및 수송은 매립지의 유체유동특성, 가스생성량, 배관망내 침출수 수분점유 상황, 배관망의 구조 및 사양 등에 따라 그 성공여부가 결정된다. 이에 따라 본 연구에서는 오래된 쓰레기 매립지에 생성된 매립가스의 포집 및 수송 메커니즘을 포집정과 지상 배관망 단계별로 분석하였고, 최종적으로 매립지 압력강하의 최소화에 따른 가스막힌 밀집구역이 발생되지 않도록 송풍기의 흡입력을 최적으로 운용하는 방법을 제안하였다.

• 한국가스학회지
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• 제6권1호
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• pp.46-51
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• 2002

지하철 공사나 도로 공사에서는 다양한 건설장비의 사용으로 인해 발생되는 진동이 가스관에 직$\cdot$간접적으로 영향을 미치고 있다. 특히, 매설가스관은 매설된 위치와 근접한 곳에서 시행되는 발파로 인한 진동영향이 큰 상태이다. 매설가스관 근처의 발파작업시 발생되는 진동에 대한 응답을 해석하기 위해서 등가선형해석법을 적용하여 지반의 비선형거동을 구현하였다. 해석 결과, 매설가스관에서의 가속도 응답치는 실측치와 근사한 결과를 보였고, Peak치 발생시간도 실측치와 거의 일치하였다. 그러므로 매설가스관의 동적해석을 할 때 일반적인 지진해석 메카니즘의 적용이 가능함을 알 수 있었다.

• 한국가스학회지
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• 제18권3호
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• pp.13-19
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• 2014

이산화탄소 포집 및 저장 시스템(CCS, Carbon dioxide Capture and Storage system)의 수송배관에 대한 연속연성파괴(DDF, Dynamic Ductile Fracture)를 연구하기 위하여 Battlle Two Curve법(BTCM)으로 CCS수송배관의 연속연성파괴거동을 해석하여 천연가스 수송배관의 연속연성파괴거동과 비교하였다. 또한, $CO_2$배관에서의 배관두께 및 사용온도에 따른 연속연성파괴 민감도를 분석함으로써 연속연성파괴에 대한 사용기준을 해석하였다. 우리나라 기후조건에 따른 $CO_2$배관두께와 수송압력 사용기준을 분석하였으며, 상온의 경우에는 기존의 천연가스용 배관을 $CO_2$배관으로 사용하기 위해서는 배관두께가 7mm이상이어야 하고 수송압력은 54bar이하이어야 함을 해석하였다.

• 전기학회논문지
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• 제57권10호
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• pp.1720-1725
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• 2008

Because of the continuous increasing of energy consumption, metallic pipelines are widely used to supply services to customers such as gas, oil, water, etc. Most common metallic pipelines are underground and are now frequently being installed in nearby electric power lines. In recent years, buried gas pipeline close to power lines can be subjected to hazardous induction effects, especially during single line to ground faults. because it can cause corrosion and it poses a threat to the safety of workers responsible for maintenance. Accordingly, it is necessary to take into consideration for analysis of induced voltage on gas pipelines in transmission lines. This paper analyzed the induced voltage on the gas pipelines due to the 154kV transmission lines in normal case and in different faulty case conditions using EMTP (Electro-Magnetic Transients Program).

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.269-274
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• 2008

For fitness-for-service analyses of underground natural gas pipelines, engineering assessment methods against possible defects need to be developed. The assessment methods for high pressure pipeline of KOGAS, was developed using the full size pipe burst tests and the finite element analysis. It included the defect assessment methods for a single and multi-corrosion, corrosion in girth welding part, corrosion in seam welding part, the mechanical damage defects as dent and gouge, crack and large plastic deformation of API 5L X65 pipe. In addition, we developed method to assess pipeline integrity by internal and external load to buried pipeline. Evaluation results were compared with other methods currently being applied to the gas pipeline. The program of Windows environment is made for easily using assessment methods. It provides a consistent user interface, so non-professional technician can easily and friendly use the FFS program from company intranet. Several evaluation programs is easily installed using one installer. Each program constitutes a common input interface and the output configuration program, and evaluation result store and can be recalled at any time. The FFS program based on independent evaluation method is used to evaluate the integrity and safety of KOGAS pipeline, and greatly contribute to safe and efficient operation of pipeline. This paper presents experimental, analytical and numerical investigations to develop the FFS methods for KOGAS pipeline, used as high pressure natural gas transmission pipeline within KOREA. Also, it includes the description of the integrated program for FFS methods.

• 한국가스학회지
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• 제2권2호
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• pp.34-39
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• 1998

국내에 액화천연가스가 도입된 이래 환경에 대한 문제를 인식함에 따라 천연가스의 수요는 계속적으로 증가하고 있다. 청정연료인 천연가스는 용접에 의해 고장력강 배관을 사용하여 각 도시로 공급되고 있다. 천연가스 공급용 배관은 공급압력에 따라 중압관과 고압관으로 구분된다. 배관은 주로 작업의 용이성으로 피복아크용접에 의해 용접되며, 현장 작업여건에 따라 다른 용접공정이 적용되기도 한다. 본 연구는 고압관으로 사용되는 API 5L X42 배관에 대한 용착금속부의 미세조직 변화와 기계적 특성을 관찰하였다.

• Journal of Mechanical Science and Technology
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• 제18권3호
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• pp.370-378
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• 2004

An autonomous pipeline inspection gauge system has been developed for determining position, orientation, curvature, and deformations such as dents and wrinkles of operating pipelines by Korea Gas Company and Seoul National University. The most important part of several subsystems is the Strapdown Inertial Measurement Unit (SIMU), which is integrated with velocity and distance sensors, weld detection system, and digital recording device. The Geometry Pipeline Inspection Gauge (GeoPIG) is designed to operate continuously and autonomously for a week or longer in operating gas pipelines. In this paper, the design concepts, system integration, and data processing/analysis method for the PIG will be presented. Results from the recent experiment for a 58 kilometer gas pipeline will be discussed.

• Journal of Mechanical Science and Technology
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• 제17권5호
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• pp.629-636
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• 2003

This paper introduces the developed geometry PIG (Pipeline Inspection Gauge), one of several ILI (In-Line Inspection) tools, which provide a full picture of the pipeline from only single pass, and has compact size of the electronic device with not only low power consumption but also rapid response of sensors such as calipers, IMU and odometer. This tool is equipped with the several sensor systems. Caliper sensors measure the pipeline internal diameter, ovality and dent size and shape with high accuracy. The IMU (Inertial Measurement Unit) measures the precise trajectory of the PIG during its traverse of the pipeline. The IMU also provide three-dimensional coordination in space from measurement of inertial acceleration and angular rate. Three odometers mounted on the PIG body provide the distance moved along the line and instantaneous velocity during the PIG run. The datum measured by the sensor systems are stored in on-board solid state memory and magnetic tape devices. There is an electromagnetic transmitter at the back end of the tool, the transmitter enables the inspection operators to keep tracking the tool while it travels through the pipeline. An experiment was fulfilled in pull-rig facility and was adopted from Incheon LT (LNG Terminal) to Namdong GS (Governor Station) line, 13 km length.