• Title, Summary, Keyword: outer tank of lng storage

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A Study on the Strength Safety of the Prestressed Concrete Outer Tank for a Membrane LNG Storage Tank (멤브레인식 LNG 저장탱크용 PC 외부탱크의 강도안전성에 관한 연구)

  • Kim, Chung-Kyun;Kim, Do-Hyun
    • Journal of the Korean Institute of Gas
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    • v.13 no.1
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    • pp.21-27
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    • 2009
  • This paper presents the numerical study on the strength safety of the prestressed concrete outer tank for a LNG storage tank, which is manufactured by sets of membrane panels with special corrugations. This study for a finite element analysis assumes that the membrane panel of the inner tank was fractured and the liquefied natural gas stored in the inner membrane tank was leaked to the prestressed concrete outer tank. The stress and displacement of the outer tank have been analyzed for five different loadings, which are originated by a hydrostatic pressure and a weight of a LNG, a temperature difference, a weight of the prestressed concrete and a boil-off gas pressure. The computed FEM results indicate that the PC outer tank with a storage capacity of 200,000$m^3$ has a good strength safety for a leaked LNG from the membrane inner tank, but the increased cryogenic loadings in which are originated by a leaked LNG decreases the strength safety of the PC structure. This may lead to the collapse of the outer storage tank.

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The Development of Life Evaluation Program for LNG Storage Tank considering Fatigue and Durability (피로 및 내구성을 고려한 LNG 저장탱크의 수명평가 프로그램 개발)

  • Kim, Jung-Hoon;Kim, Young-Gu;Jo, Young-Do
    • Journal of the Korean Institute of Gas
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    • v.21 no.3
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    • pp.39-45
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    • 2017
  • The LNG storage tank as core facility of LNG industry is mainly composed of the inner tank of nikel 9% steel and the outer tank of prestressed concrete. To respond proactively increased risk of structure performance deterioration due to fatigue of the inner tank and durability reduction of the outer tank, life evaluation program for LNG storage tank is needed. In this study, life evaluation program for LNG storage tank was developed to assess fatigue of the inner tank and durability(carbonation and chloride attack) of the outer tank. By defining the main three scenarios in the inner tank, the fatigue life analysis is conducted from structural analysis and Miner's damage rule. Carbonation progress of the outer tank is predicted according to thickness of cover concrete by using carbon dioxide contents and data of penetration depth. To consider a variety of input conditions and a reliability in results of chloride attack, the evaluation of choride attack for the outer tank is constructed through Life-365 program of open source.

Analytical study of failure damage to 270,000-kL LNG storage tank under blast loading

  • Lee, Sang Won;Choi, Seung Jai;Kim, Jang-Ho Jay
    • Computers and Concrete
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    • v.17 no.2
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    • pp.201-214
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    • 2016
  • The outer tank of a liquefied natural gas (LNG) storage tank is a longitudinally and meridianally pre-stressed concrete (PSC) wall structure. Because of the current trend of constructing larger LNG storage tanks, the pre-stressing forces required to increase wall strength must be significantly increased. Because of the increase in tank sizes and pre-stressing forces, an extreme loading scenario such as a bomb blast or an airplane crash needs to be investigated. Therefore, in this study, the blast resistance performance of LNG storage tanks was analyzed by conducting a blast simulation to investigate the safety of larger LNG storage tanks. Test data validation for a blast simulation of reinforced concrete panels was performed using a specific FEM code, LS-DYNA, prior to a full-scale blast simulation of the outer tank of a 270,000-kL LNG storage tank. Another objective of this study was to evaluate the safety and serviceability of an LNG storage tank with respect to varying amounts of explosive charge. The results of this study can be used as basic data for the design and safety evaluation of PSC LNG storage tanks.

A Study on the Strength Safety Analysis of a Full Containment LNG Storage Tank Due to a Wind Pressure (완전밀폐식 LNG 저장탱크에 작용하는 풍압에 의한 강도안전 해석에 관한 연구)

  • Kim, Chung-Kyun;Jeong, Nam-In
    • Journal of the Korean Institute of Gas
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    • v.12 no.1
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    • pp.36-41
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    • 2008
  • Using the finite element analysis, this paper presents the strength safety of a side wall of an outer tank and a roof structures in a full containment LNG storage tank system. The outer tank structure in which is constructed with a prestressed concrete is forced by internal hydrostatic and hydrodynamic pressures of a leaked LNG and an external wind pressure including a typhoon one. The FEM computed results show that the ring beam between a side wall of an outer tank and a roof structure supports most of the internal and the external loads. This means that the design point of the outer tank system is a ring beam structure and the other one is a center part of the roof structure. In this FE analysis model of a full containment LNG tank system, the outer tank and the roof structures are safe for the given combined loads such as an internal leaked LNG pressure and an external typhoon pressure.

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A Development of Condition Evaluation Standard Considering Structural Characteristic for Members of LNG Outer Storage Tanks (LNG 외조 저장탱크의 구조적 특성을 고려한 상태평가 기준 개발)

  • Choi, Kyoung-Jae;Seo, Chang-Joo;Kim, Young-Gu;Jo, Young-Do;Kim, Jung-Hoon
    • Journal of the Korean Institute of Gas
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    • v.21 no.5
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    • pp.64-69
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    • 2017
  • South Korea is the world's second-largest importer of LNG and possess about 70 tanks which are in operation by 2017. Thirty years as the design warranty period have exceeded since LNG storage tanks as the core facility of LNG industry were constructed in 1986. The LNG storage tank is under precision safety diagnosis from 2014 due to urban gas business act amendment. There is no criteria of condition evaluation for outer tank of LNG storage tank at the time of precision safety diagnosis. Through analysis of structural characteristic of LNG storage tank and civil structure condition evaluation standards, the criteria of condition evaluation for main members was developed. The criteria of objective condition evaluation can improve safety and reliability of LNG storage tank and suggest matenance criteria.

A Study on the Design Optimization of Corner Pprotection for LNG Storage Tank (LNG저장탱크 코너프로텍션의 설계 최적화에 관한 연구)

  • Kim, Hyung-Sik;Hong, Seong-Ho;Seo, Heung-Seok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.9
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    • pp.1384-1390
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    • 2004
  • The full containment Liquefied Natural Gas(LNG) storage tank is based on a double liquid container concept : two separate containers, one within the other, are capable of containing the LNG. The outer concrete tank provides comer protection(secondary containment) to withstand and safely contain any spill from the inner tank. The comer protection is installed on inside corner surface of outer concrete tank. Because of high and complex stresses, corner protection is designed by ASME section ⅧI Div. 2, Appendix 4 on behalf of API 620 which is main design code for LNG tank. Design guidelines to determine design factors such as liner thickness and knuckle radius are not well understood because Appendix 4 is the design method not based on equation but FEM. Recently, the volume of LNG tank shows a tendency to increase. So it is necessary to set up the design guidelines to cope with change of LNG tank capacity and height/diameter ratio. In this paper, optimum design of corner protection was performed and the design guidelines were suggested by the results of FEM for LNG tanks which have different capacities and height/diameter ratio.

Analytical Assessment of Blast Damage of 270,000-kL LNG Storage Outer Tank According to Explosive Charges (270,000 kL급 LNG 저장 탱크 외조의 폭발량에 따른 손상도 해석적 평가)

  • Kim, Jang-Ho Jay;Choi, Seung-Jai;Choi, Ji-Hun;Kim, Tae-Kyun;Lee, Tae-Hee
    • Journal of the Korea Concrete Institute
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    • v.28 no.6
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    • pp.685-693
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    • 2016
  • The outer tank of a liquefied natural gas (LNG) storage tank is a longitudinally and meridionally pre-stressed concrete (PSC) wall structure. Because of the current trend of constructing larger LNG storage tanks, the pre-stressing forces required to increase wall strength must be significantly increased. Because of the increase in tank sizes and pre-stressing forces, an extreme loading scenario such as a bomb blast or an airplane crash needs to be investigated. Therefore, in this study, the blast resistance performance of LNG storage tanks was analyzed by conducting a blast simulation to investigate the safety of larger LNG storage tanks. Test data validation for a blast simulation of reinforced concrete panels was performed using a specific FEM code, LS-DYNA, prior to a full-scale blast simulation of the outer tank of a 270,000-kL LNG storage tank. Another objective of this study was to evaluate the safety and serviceability of an LNG storage tank with respect to varying amounts of explosive charge. The results of this study can be used as basic data for the design and safety evaluation of PSC LNG storage tanks.

On the Leakage Safety Analysis of Membrane LNG Storage Tank With Thermal Resistance Effects (열저항 효과를 고려한 멤브레인식 LNG 저장탱크의 누설 안전성에 관한 연구)

  • Kim C.K.;Cho S.H.;Suh H.S.;Hong S.H.;Lee S.R.;Kim Y.G.;Kwon B.K.
    • Journal of the Korean Institute of Gas
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    • v.8 no.4
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    • pp.1-7
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    • 2004
  • In this paper, the FE analysis has been presented for the leakage safety of the membrane LNG storage tank based on the thermal resistance effects between the insulation panel and prestressed concrete structure. The FEM calculated results show that the leakage safety of plywood and polyurethane materials does not guarantee any more due to a strength failure of the insulation structure. But the PC structure of outer tank may delay leaked LNG of 10 days even though the inner tank and insulation structure are simultaneously failed. This means that the membrane LNG storage tank may be safe because of the stiffness of the outer tank.

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Consistent thermal analysis procedure of LNG storage tank

  • Jeon, Se-Jin;Jin, Byeong-Moo;Kim, Young-Jin;Chung, Chul-Hun
    • Structural Engineering and Mechanics
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    • v.25 no.4
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    • pp.445-466
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    • 2007
  • As the LNG (Liquefied Natural Gas) tank contains cryogenic liquid, realistic thermal analyses are of a primary importance for a successful design. The structural details of the LNG tank are so complicated that some strategies are necessary to reasonably predict its temperature distribution. The proposed heat transfer model can consider the beneficial effects of insulation layers and a suspended deck on temperature distribution of the outer concrete tank against cryogenic conditions simply by the boundary conditions of the outer tank model. To this aim, the equilibrium condition or heat balance in a steady state is utilized in a various way, and some aspects of heat transfer via conduction, convection and radiation are implemented as necessary. Overall thermal analysis procedures for the LNG tank are revisited to examine some unjustifiable assumptions of conventional analyses. Concrete and insulation properties under cryogenic condition and a reasonable conversion procedure of the temperature-induced nonlinear stress into the section forces are discussed. Numerical examples are presented to verify the proposed schemes in predicting the actual temperature and stress distributions of the tank as affected by the cryogenic LNG for the cases of normal operation and leakage from the inner steel tank. It is expected that the proposed schemes enable a designer to readily detect the effects of insulation layers and a suspended deck and, therefore, can be employed as a useful and consistent tool to evaluate the thermal effect in a design stage of an LNG tank as well as in a detailed analysis.

Numerical Analysis on the Stress and Deformation Characteristics of LNG Membrane Storage Tank System with Corner Protection (코너프로텍션 설치에 따른 멤브레인 LNG 저장탱크 시스템의 응력 및 변형거동 특성에 관한 수치해석)

  • Kim, Chung-Kyun
    • Journal of the Korean Institute of Gas
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    • v.13 no.6
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    • pp.9-14
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    • 2009
  • In this study, the stress and deformation characteristics of corner protection in which is fabricated in an insulation area have been analyzed using a finite element method. The proposed corner protection may increase the strength and leakage safeties of conventional LNG storage system. The stress and deformation of LNG storage tank system are computed for an insulation panel box, membrane inner tank, and prestressed concrete outer tank. The FEM computed results indicate that the stress and displacement of new membrane LNG tank system with a corner protection between an inner tank and an outer tank are reduced in comparison to those of a conventional membrane LNG tank. This is explained that the strength safety of LNG membrane tank system may be increased due to a strength stiffness of a corner protection.

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