• Title/Summary/Keyword: LNG-FPSO

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Motion and Sloshing Analysis for New Concept of Offshore Storage Unit

  • Ha, Mun-Keun;Kim, Mun-Sung;Paik, Bu-Keun;Park, Chung-Hum
    • Journal of Ocean Engineering and Technology
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    • v.16 no.1
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    • pp.1-7
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    • 2002
  • 본 논문에서는 선체 하부에 moonpool과 bilge step을 장착한 새로운 개념으의 LNG-FPSO를 운동감소와 cargo, operation tank의 슬로싱 현상의 관점에서 기술하였다. LNG-FPSO의 주요제원은$L\times B\times D\times t(design)=270.0\times51.0\times32.32\times13.7(m)$ 이고 적용조건은 total corgo capacity of 161KT at 98% loading condition 이다. LNG-FPSO의 운동감소의 목적으로 2개의 moonpool과 선체하부 bilge 부분에 사각 step을 장착하였다. LNG-FPSO의 운동해석을 위해 단순화된 경계조건을 만족하는 선형화된 3차원 diffraction theory를 사용하였고 LNG-FPSO의 연성된 6-자유도 운동응답을 계산하였다. LNG-FPSO의 정확한 Roll 운동을 추정하기 위해 점성효과는 Himeno(1981)가 제안한 경험식을 사용하였다. Moonpool의 크기에 따른 운동감소의 경향을 파악하기 위해 이론적 계산과 실험적 방법으로 수행하였다. Moonpool 크기와 bilge step의 효과를 최적화하기 위해 총9가지의 case를 설정하였다. 이론 및 실험 결과로부터 본 LNG-FPSO는 moonpool과 bilge step의 장착으로 인한 감쇠력의 증가로 운동성능이 우수하다. 본 LNG-FPSO의 운동 응답중, 특별히 roll 운동이 다른 drillship, shuttle tanker등의 선박과 비교하여 상당히 작았고 이는 moonpool과 blige step의 장착으로 인한 효과로 판단된다. Cargo tank와 operation tank 크기를 검토 하기 위해 불규칙 해상중 sloshing 해석을 chamfer를 갖는 LNG-FPSO의 No.2, No.5 tank 벽면의 압력 분포와 자유표면의 time history에 초점을 맞추어 수행하였다. 최종적으로 tank 크기를 최적화 하였고 최적화된 tank는 선수사파와 횡파상태의 모든 filling에서 공진현상과 충격압력이 발생하지 않음을 확인하였다.

Reliability Analysis of LNG FPSO Liquefaction Cycle in DEVS Environment (DEVS 환경에서 LNG FPSO 액화 공정의 신뢰도 해석)

  • Ha, Sol;Ku, Namkug;Roh, Myung-Il
    • Korean Journal of Computational Design and Engineering
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    • v.18 no.2
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    • pp.138-147
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    • 2013
  • The liquefaction process system is regarded as primary among all topside systems in LNG FPSO. This liquefaction process system is composed of many types of equipment. LNG equipment on offshore plants has quite different demands on the equipment compared to traditional onshore LNG plants, so the reliability analysis of this process system needs to be performed. This study investigates how DEVS formalism for discrete event simulation can be used to reliability analysis of the liquefaction cycle for LNG FPSO. The reliability analysis method based on DEVS formalism could be better model for reflecting the system configuration than the conventional reliability analysis methods, such as fault tree analysis and event tree analysis.

Simulation of Membrane-absorption Hybrid Process for LNG-FPSO (LNG-FPSO용 막-흡수 하이브리드 공정 전산모사)

  • Min, Kwang-Joon;Cho, Habin;Kim, Jin-Kuk;Kang, Sang Wook
    • Membrane Journal
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    • v.28 no.2
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    • pp.90-95
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    • 2018
  • A process design was performed for a removal of acid gases using membrane-absorption hybrid system in LNG-FPSO. Commercial process simulator Promax version 4.0 was utilized for comparing acid gases removal capabilities of amine absorption process and hybrid process. Simulation results show hybrid process could be small amine solvent circulate rate, energy consumption, equipment sizing compared to typical amine absorption process. As a result, hybrid process which is small footprint and energy saving process may be a good solution for the pre-treatment of natural gas in LNG-FPSO.

A Study on the Development of Maintenance System for Equipment of LNG-FPSO Ship (LNG-FPSO 선박 장비들의 보전활동 지원시스템 개발에 관한 연구)

  • Lee, Soon-Sup;Kang, Donghoon;Lee, Jong-Hyun;Lee, Seung-Jun
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.22 no.2
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    • pp.233-239
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    • 2016
  • In this paper, a maintenance system is developed for LNG-FPSO topside and hullside equipment based CBM (Condition Based Maintenance) methodology. First, the development system defined the PWBS(Product Work Breakdown Structure) of major equipment of LNG-FPSO. Second, the development system developed the failure analysis, economic evaluation for optimal maintenance plan and database systems that save and manage information about equipment, failure mode, failure rate and failure cause. Finally, the verification of the development system was applied to the inlet system of topside and the pump tower system of hullside and the system was confirmed the effectiveness of CBMS(Condition Based Maintenance System).

Multi-floor Layout for the Liquefaction Process Systems of LNG FPSO Using the Optimization Technique (최적화 기법을 이용한 LNG FPSO 액화 공정 장비의 다층 배치)

  • Ku, Nam-Kug;Lee, Joon-Chae;Roh, Myung-Il;Hwang, Ji-Hyun;Lee, Kyu-Yeul
    • Journal of the Society of Naval Architects of Korea
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    • v.49 no.1
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    • pp.68-78
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    • 2012
  • A layout of an LNG FPSO should be elaborately determined as compared with that of an onshore plant because many topside process systems are installed on the limited area; the deck of the LNG FPSO. Especially, the layout should be made as multi-deck, not single-deck and have a minimum area. In this study, a multi-floor layout for the liquefaction process, the dual mixed refrigerant(DMR) cycle, of LNG FPSO was determined by using the optimization technique. For this, an optimization problem for the multi-floor layout was mathematically formulated. The problem consists of 589 design variables representing the positions of topside process systems, 125 equality constraints and 2,315 inequality constraints representing limitations on the layout of them, and an objective function representing the total layout cost. To solve the problem, a hybrid optimization method that consists of the genetic algorithm(GA) and sequential quadratic programming(SQP) was used in this study. As a result, we can obtain a multi-floor layout for the liquefaction process of the LNG FPSO which satisfies all constraints related to limitations on the layout.

Research of design challenges and new technologies for floating LNG

  • Lee, Dong-Hyun;Ha, Mun-Keun;Kim, Soo-Young;Shin, Sung-Chul
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.6 no.2
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    • pp.307-322
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    • 2014
  • With the rate of worldwide LNG demand expected to grow faster than that of gas demand, most major oil companies are currently investing their resources to develop floating LNG-FLNG (i.e. LNG FSRU and LNG FPSO). The global Floating LNG (FLNG) market trend will be reviewed based on demand and supply chain relationships. Typical technical issues associated with FLNG design are categorized in terms of global performance evaluation. Although many proven technologies developed through LNG carrier and oil FPSO projects are available for FLNG design, we are still faced with several technical challenges to clear for successful FLNG projects. In this study, some of the challenges encountered during development of the floating LNG facility (i.e. LNG FPSO and FSRU) will be reviewed together with their investigated solution. At the same time, research of new LNG-related technologies such as combined containment system will be presented.

A Study on the Flow Assurance in Subsea Pipeline Considering System Availability of Topside in LNG-FPSO (LNG-FPSO에서 상부구조물의 시스템 가용도를 고려한 해저 배관의 유동안정성 연구)

  • Kim, Young-Min;Choi, Jun-Ho;Lee, Jeong-Hwan
    • Journal of the Korean Institute of Gas
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    • v.24 no.6
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    • pp.18-27
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    • 2020
  • This study presents flow assurance analysis in subsea pipeline considering system availability of topside in LNG-FPSO. A hydrate management strategy was established, which consisted of PVCap experiments, system availability analysis of LNG-FPSO topside, hydrate risk analysis in the pipeline, and calculation of PVCap injection concentration. The experimental data required for the determination of PVCap injection concentration were obtained by measuring the hydrate induction time of PVCap at the subcooling temperatures of 6.1, 9.2, and 12.1℃. The availability of LNG-FPSO topside system for 20 years was 89.3%, and the longest downtime of 50 hours occurred 2.9 times per year. The subsea pipeline model for multiphase flow simulation was created using field geometry data. As a result of risk analysis of hydrate plugging using subsea pipeline model, hydrate was formed at the end of flowline in 23.2 hours under the condition of 50 hours shutdown. The injection concentration of PVCap was determined based on the PVCap experiment results. The hydrate plugging in subsea pipeline of LNG-FPSO can be completely prevented by injecting PVCap 0.25 wt% 2.9 times per year.

Investigation on Efficiency Improvement of the Nitrogen Expander Cycle : Natural Gas Liquefaction Process for LNG-FPSO (LNG-FPSO(Liquefied Natural Gas-Floating Production Storage and Offloading)용 질소 팽창 사이클의 효율 개선에 대한 연구)

  • Baek, Seung-Whan;Jeong, Sang-Kwon;Kim, Sun-Young
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.22 no.7
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    • pp.442-447
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    • 2010
  • FPSO (Floating Production Strorage and Offloading) method for LNG industry is efficient and facile compared to onshore NG (Natural Gas) treatment facility. Five simple natural gas liquefaction cycles for FPSO are presented and simulated in this paper. SMR (Single Mixed Refrigerant) cycle, SNE (Single Nitrogen Expander) cycle, DNE (Double Nitrogen Expander) cycle, PNE (Precooled Nitrogen Expander) cycle, and PDNE (Precooled Double Nitrogen Expander) cycle are compared. Simple analysis results in this paper show that precooling process and adding an expander in the liquefaction cycle is an effective way to increase liquefaction efficiency.

Case Study for Development of Maintenance System for Equipment of LNG-FPSO Topside (LNG-FPSO Topside 장비를 위한 보전시스템 개발을 위한 사례 연구)

  • Lee, Soon-Sup;Kim, Jong-Wang
    • Journal of Ocean Engineering and Technology
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    • v.28 no.6
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    • pp.533-539
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    • 2014
  • A maintenance system for an offshore plant uses an optimal maintenance method, process, and period based on operation information data and economic evaluation techniques. Maintenance is performed after one or more indicators show that equipment is going to fail or that equipment performance is deteriorating. A maintenance system is based on the use of real-time data to prioritize and optimize the LNG-FPSO topside equipment resources.

LNG 슬로싱 현상을 고려한 FPSO와 LNG운반선의 동적거동에 관한 연구

  • Lee, Seung-Jae;Go, Jeong-Min;Gong, Ji-Hun
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2011.11a
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    • pp.5-7
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    • 2011
  • LNG 운반선이 대형화 됨에 따라 슬로싱의 동적거동에 대한 영향에 대한 관심이 증가하고 있다. 본 연구에서는 시간영역에서 슬로싱 현상과 FPSO와 LNG운반선의 거동을 동적으로 연성하여, LNG 슬로싱이 두 부유체의 global performance에 미치는 영향을 시간영역에서 시뮬레이션하였다.

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