• Journal of Advanced Marine Engineering and Technology
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• v.34 no.1
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• pp.46-52
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• 2010

In this study, several types of natural gas liquefaction processes using two staged Inter-cooler are simulated and designed to secure a competitiveness in the industry of natural gas liquefaction plant. These processes are based on basic cascade process, and all of these are improved with two staged compressors type. One of types is applied Inter-cooler to each cycle such as propane, ethylene, methane, the other type is applied Inter-cooler to whole cycle. These processes are compared characteristics of performance with basic process. Cascade process with two staged Inter-cooler in the whole cycle is on the top ranked with increment ratio of COP about 13.7 ~ 20.5%, and yield efficiency of this process are improved comparing with the basic process by 23.8% ~ 35% lower specific power, respectively.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.6
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• pp.798-805
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• 2010

There are no domestic researches of plate fin heat exchanger in the field of cryogenic such as LNG FPSO liquefaction plant. In this study, condensing heat transfer characteristics of nitrogen according to three kinds of fin type in the plate fin heat exchanger were analyzed through simulation and experiment to secure independent technologies. In the simulation, nitrogen was condensed at 69bar and $-140^{\circ}C$ in serrated and wavy fin of plate-fin heat exchanger. The serrated fin shows the highest value of local heat transfer coefficient, followed by wavy and plain fin. The experimental results were shown errors less than 12% comparing with the simulation results.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.4
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• pp.358-363
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• 2012

The simulation investigation on the availability of LNG plant with scenario of failure events and failure rate has been carried out. This study focuses on the availability, productivity, criticality induced by failure rate of major equipment. The methodologies for simulation such as the equipment classification of LNG plant and failure type and event schematic are established. The availability and mean time to repair have second order function profile in the all cases except general equipment, but these profiles have different inclination. The production and criticality of the specified LNG plant, simulated by Monte-Carlo algorithm, is located in the range of P = 86~92% and PL = 6~13%.

• Korean Journal of Construction Engineering and Management
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• v.15 no.3
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• pp.47-57
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• 2014

LNG plant projects tend to be implemented in overseas owing to its characteristics, so their project management scheme is somewhat different from those of general projects. Value chain in a LNG plant project includes exploration/production of gases, physical liquefaction/chemical conversion processes, transportation and storage. Key factors in the chain include liquefaction process (including ultra-low temperature liquefaction) to convert natural gas into liquid materials or fuel, and Front End Engineering Design (FEED) package, as well as Engineering, Procurement and Construction (EPC) technology comprising control, operation and construction. Success of a complex LNG plant project implemented in overseas depends on decision-making process in project management. Accordingly, to develop a decision-making model in of plant construction, the study extracted none factors in project management by EPC stage and assessed importance of each factor. The result showed that items in both project management and project risk management are important. Especially, the study developed a decision-making model in the construction stage of a LNG plant project based on the project management factors and importance assessment. The developed decision-making model would lay groundwork in building a decision-making system in construction stage of project management.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.732-741
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• 2020

Environmental regulations have recently been strengthened. Consequently, floating LNG(Liquefied Natural Gas) power plants are being developed, which are new power generation plants that generate electricity by utilizing LNG. A floating LNG power plant generates BOG(Boil-Off Gas) during its operation, and the system design of such a plant should be capable of removing or re-liquefying BOG. However, the design of an offshore plant differs according to the marine requirements. Hence, a process simulation model of the BOG re-liquefaction system is needed, which can be continuously modified to avoid designing the floating LNG power plant through trial and error. In this paper, to develop a model appropriate for the floating LNG power plant, a commercial process simulation program was employed. Depending on the presence of refrigerants, various BOG re-liquefaction systems were modeled for comparing and analyzing the re-liquefaction rates and liquid points of BOG. Consequently, the BOG re-liquefaction system model incorporating nitrogen refrigerants is proposed as the re-liquefaction system model for the floating LNG power plant.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.76.2-76.2
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• 2011

석탄으로부터 합성석유를 생산하는 상용기술을 도입하여 건설하고 이와 더불어 원천기술 개발을 위한 국산화 기술 개발을 병행하여 향후 고유가 시대를 대비한 국가 에너지 안보 확립과 국내 기술 개발의 가속화를 추구해야 할 필요성이 대두되고 있다. 본 타당성 조사는 3종류의 석탄(호주 Wyong탄, 인도네시아 NTC탄, 인도네시아 KBB탄)으로부터 가스화에 의하여 합성석유스를 생산하는 공정에 대한 타당성 조사(Feasibility Study, FS)를 Class 5(하한 -50~-20%, 상한 30~100%)의 정확도로 수행하는 것을 내용으로 하고 있다. 플랜트의 규모는 합성석유 기준으로 20,000배럴/일이다. 플랜트의 건설을 위해서 광양제철소 슬래그처리장 내 12만평 부지에 조성 중인 포스코 SNG 생산공장 부지의 일부를 사용하는 것을 기준으로 하였다. 일반적으로 석탄의 종류에 따라서 가스화기의 종류 및 성능이 결정된다. 본 타당성 조사 연구에서 선정된 3종류의 석탄의 조성, 발열량, 회분 함량 등의 특성을 고려하여 각각의 석탄에 적합한 현존하는 상용급 가스화기를 선정하였다. 해당 석탄이 가스화기 종류에 따라 적절한 전처리 과정(건조, 분쇄, 슬러리화)을 거친 후 가스화기에 공급되는 것을 가정하여 석탄의 원소분석 조성, 발열량, 회분함량, 회분조성, 회 용융점 등의 변수에 따라서 각각 해당 가스화기에서 가스화되었을 때의 생성되는 합성가스의 조건을 시뮬레이션을 통하여 얻었다. 가스화기 시뮬레이션 결과를 토대로 합성석유 및 합성천연가스 생산을 위한 공정의 물질수지식 및 에너지수지식이 계산되었으며 이로부터 각 공정에서 발생되는 부생성물과 폐기물에 대한 양이 결정되고 이를 처리하는 방안 등도 제시되었다. 실증시설은 20,000배럴/일 규모의 CTL 및 전기 병산 시설이 적합하다. 더 큰 규모 공장은 투자비가 너무 커서 유가 또는 석탄가 변동에 따라 사업의 수익성이 크게 변하여 위험도가 큰 단점이 있기 때문이다. CTL 공장에 전기 병산이 추천되는 이유는 산소생산공장(APU), 압축 등 석탄전환공장에는 자체적인 전기수요가 막대하여 따로 스팀터빈용 발전소를 운영하므로 이를 효율적으로 대체하고자 하기 때문이다. 즉, 석탄가스화에 의해 기름을 최대한 만들고 미반응가스는 가스터빈 및 스팀터빈의 복합발전에 의해 고효율로 전기를 생산하면 최소의 비용으로 최대한 전기를 생산하여 자체소비 전력을 충당하고 남는 전기는 판매하여 수익률을 높일 수 있다.

• Transactions of the KSME C: Technology and Education
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• v.1 no.1
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• pp.99-105
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• 2013

In this paper, we carried out the basic design of 36 MTD natural gas BOG re-liquefaction system to recover the generated natural gas during performance test of LNG pump and natural gas compressor. The re-liquefaction process of natural gas is designed to have 1500 kg/h of liquefaction rate with reverse Brayton refrigeration cycle. With the designed process, the variation of liquefaction rate is calculated for various inlet conditions of feed gas. From results, the liquefaction rate is more sensitive for inlet temperature than gas composition. The specifications of equipments such as gas blower, natural gas compressor, cryogenic heat exchanger and nitrogen compander are determined on the basis of the designed process. The requirement of power consumption and cooling water are also determined through the basic design.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.7
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• pp.949-955
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• 2018

Hardware-in-the-loop (HIL) simulation is a technique that can be employed for developing and testing complex real-time embedded systems. HIL simulation provides an effective platform for verifying power management system (PMS) performance of liquefied natural gas carriers, which are high value-added vessels such as offshore plants. However, HIL tests conducted by research institutes, including domestic shipyards, can be protracted. To address the said issue, this study proposes a field programmable gate array (FPGA) based PMS-HIL simulator that comprises a power supply, consumer, control console, and main switchboard. The proposed HIL simulation platform incorporated actual equipment data while conducting load sharing PMS tests. The proposed system was verified through symmetric, asymmetric, and fixed load sharing tests. The proposed system can thus potentially replace the standard factory acceptance tests. Furthermore, the proposed simulator can be helpful in developing additional systems for vessel automation and autonomous operation, including the development of energy management systems.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.5
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• pp.809-818
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• 2022

The number of ships using liquefied natural gas (LNG) as fuel is increasing to respond to the International Maritime Organization's (IMO) air pollutant emission regulations. At the same time, the need to expand LNG bunkering infrastructure for stable fuel supply and demand for ships is emerging. LNG bunkering is carried out in three ways: truck to ship (TTS), pipe to ship (PTS), and ship to ship (STS). In foreign countries, all three methods are being carried out, but in Korea, LNG bunkering is carried out only with the TTS method owing to the lack of infrastructure. LNG bunkering is a high-risk operation. For safe bunkering operations, the competence of the workers is extremely important, and a professional training course is required to strengthen the competence. This study was conducted to design training contents for LNG bunkering workers for fostering LNG bunkering experts and performing safe and systematic bunkering work. To this end, the current status of LNG-fueled ships and bunkering was identified, and related domestic and abroad educational contents were analyzed. In addition, opinions on the importance of educational contents were collected through expert questionnaires. Consequently, we designed training contents suitable for various training targets and divided them into basic and advanced training courses, with a duration of 4 days, and proposed. Based on the designed training contents, if additional research is conducted by sufficiently reflecting Korea's bunkering environment, it will be of great help to improve the competence of LNG bunkering workers and to foster human resources.

• Journal of Navigation and Port Research
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• v.43 no.3
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• pp.143-152
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• 2019

In this paper, the towing stability of the LNG bunker barge was estimated. Currently, LNG bunkering barge is being developed for the bunkering of LNG (Liquefied Natural Gas), an eco-friendly energy source. Since the LNG bunkering barge assumes the form of a towed ship connected to the tow line, the towing stability of the LNG bunker barge is crucial f not only for the safety of the LNG bunker barge but also the neighboring sailing vessels. In the initial stages, a numerical code for towing simulation was developed to estimate the towing stability of the LNG bunkering barge. The MMG (Maneuvering Mathematical modeling Group) model was applied to the equations of motion while the empirical formula was applied to the maneuvering coefficients for use in the initial design stage. To validate the developed numerical code, it was compared with published calculation and model test results. Towing simulations were done based on the changing skeg area and the towing position of the LNG bunkering barge using the developed numerical codes. As a result, the suitability of the designed stern skeg area was confirmed.