• Proceedings of the Korea Information Processing Society Conference
• /
• 2009.11a
• /
• pp.919-920
• /
• 2009

액화 천연 가스 플랜트 시뮬레이터는 막대한 자본 투자가 필요한 대형 시스템 설계 및 건설 단계에서 사전에 설계 오류 검출 및 시스템 검증을 함으로써 많은 비용을 절약해줄 수 있는 중요한 시스템이다. 이 연구에서는 플랜트, 시뮬레이터, 운전원 훈련 시스템 및 제어시스템을 운전하는 과정에서 발생하는 정보를 효과적으로 처리하기 위해서 구축되는 정보 처리 시스템의 기본 설계에 관한 내용을 소개한다. 전체 시스템은 물리적 플랜트와 가상 플랜트로 나눌 수 있고 가상 플랜트는 시뮬레이터와 운전원 훈련 시스템으로 구현되며, 제어 시스템은 PLC로 구현하고 Modubus 프로토콜과 OPC 서버를 통해 데이터 처리가 가능하다. 플랜트로부터 생성되는 데이터 처리에서는 실시간 데이터 처리 속도가 중요하므로 실시간 데이터베이스를 도입하였다. 실제 플랜트 데이터와 시뮬레이터 데이터는 상호 교환이 가능하도록 구성하였다. 본 시스템 설계는 기본 설계 단계이므로 향후 LNG 플랜트에 적용하기 위해서는 상세 설계가 필요하다.

• Korean Chemical Engineering Research
• /
• v.59 no.3
• /
• pp.345-358
• /
• 2021

This study focuses on the development of the liquid air production process that uses LNG (liquefied natural gas) cold energy which usually wasted during the regasification stage. The liquid air can be transported to the LNG exporter, and it can be utilized as the cold source to replace certain amount of refrigerant for the natural gas liquefaction. Therefore, the condition of the liquid air has to satisfy the available pressure of LNG storage tank. To satisfy pressure constraint of the membrane type LNG tank, proposed process is designed to produce liquid air at 1.3bar. In proposed process, the air is precooled by heat exchange with LNG and subcooled by nitrogen refrigeration cycle. When the amount of transported liquid air is as large as the capacity of the LNG carrier, it could be economical in terms of the transportation cost. In addition, larger liquid air can give more cold energy that can be used in natural gas liquefaction plant. To analyze the effect of the liquid air production amount, under the same LNG supply condition, the proposed process is simulated under 3 different air flow rate: 0.50 kg/s, 0.75 kg/s, 1.00 kg/s, correspond to Case1, Case2, and Case3, respectively. Each case was analyzed thermodynamically and economically. It shows a tendency that the more liquid air production, the more energy demanded per same mass of product as Case3 is 0.18kWh higher than Base case. In consequence the production cost per 1 kg liquid air in Case3 was $0.0172 higher. However, as liquid air production increases, the transportation cost per 1 kg liquid air has reduced by $0.0395. In terms of overall cost, Case 3 confirmed that liquid air can be produced and transported with $0.0223 less per kilogram than Base case.

• Journal of the Korean Institute of Gas
• /
• v.17 no.3
• /
• pp.27-32
• /
• 2013

Natural gas liquefaction process which is operated under cryogenic condition spends large amount of energy. Most of energy in the natural gas liquefaction process is consumed by compressors. Therefore, minimizing energy consumption of compressors is an important issue in process design and operation. Among various natural gas liquefaction processes, propane pre-cooled mixed refrigerant (C3MR) process consists of mixed refrigerant system and pure refrigerant system. In this study, to find the optimal design of pure refrigerant system, pure refrigerant cycle is simulated on different number of pressure levels and the necessary energy of each design is compared. After that, the driver selection model is applied to analyse each processes, which has different number of equipments, in terms of cost. As the result, the design using many equipments spends lower energy. Using this result, this study suggests standard of process design selection by the cost term.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.23 no.5
• /
• pp.653-660
• /
• 1999

This work describes analysis on the effect of inlet air cooling by the cold energy of liquefied natural gas(LNG) on the performance of gas turbines. Gas turbine off-design analysis program to simulate the influence of compressor inlet temperature variation is prepared and an inlet air cooler is modeled. It is shown that the degree of power augmentation is much affected by the humidity of inlet air. If the humidity is low enough, that is the water content of the air does not condense, the temperature drop amounts to $18^{\circ}C$, which corresponds to more than 12% power increase, in case of a $1350^{\circ}C$ class gas turbine with methane as the fuel. Even with 60% humidity, about 8% power increase is possible. It is found that even though the fuel contains as much as 20% ethane in addition to methane, the power improvement does not change considerably. It is observed that if the humidity is not too high, the current system is feasible oven with conceivable air pressure loss at the inlet air cooler.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.21 no.6
• /
• pp.1218-1224
• /
• 2017

With the increasing risk in building liquefied natural gas carriers (LNGC), pre-simulation of various scenarios is required for system integration and safe operation. In particular, the power management system (PMS) is an important part of the LNGC; it works in tight integration with the power control systems to achieve the desired performance and safety. To verify and improve unpredicted errors, we implemented a simulation model of power generation and consumption for testing PMS based on software-in-the-loop (SIL) method. To control and verify the PMS, numeric and physical simulation modeling was undertaken utilizing MATLAB/Simulink. In addition, the simulation model was verified with a load sharing test scenario for a sea trial. This simulation allows shipbuilders to participate in new value-added markets such as commissioning, installation, operation, and maintenance.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.29 no.2
• /
• pp.162-170
• /
• 2009

As one of promising solutions to overcome high oil price and energy crisis, the construction market of high value-added LNG plants is spotlighted world widely. The purpose of this manuscript is to introduce domestic activities to develop risk assessment technology against overseas monopolization. After analyzing relevant specific features and their technical levels, risk assessment program, non-destructive reliability evaluation strategy and safety criteria unification class are derived as core technologies. These IT-based convergence technologies can be used for enhancement of LNG plant efficiency, in which the modular parts are related to a system with artificial optimized algorithms as well as diverse databases of facility inspection and diagnosis fields.

• Journal of the Korean Institute of Gas
• /
• v.8 no.3 s.24
• /
• pp.57-62
• /
• 2004

This study is to assess the safety of the process facilities and fire fighting facilities for LNG storage tank which is the main facility in the LNG receiving terminal. The LNG storage tank(capacity : 140,000kl, type : aboveground, inner tank $9\%$ Ni steel plate, outer tank : prestressed concrete) was designed by foreign country up to now, but it has designed by domestic technology as the fifth in the world is under construction now.

• Clean Technology
• /
• v.20 no.3
• /
• pp.314-320
• /
• 2014

The purpose of this work is to optimize composition of mixture refrigerants used in the C3MR (Propane & Mixed Refrigerants) process by a statistical optimization technique. C3MR studied in this work is one of widely used commercial natural gas liquefaction processes with high efficiency. Process simulation was performed in a commercial process simulator and methane ($C_1$), ethane ($C_2$), propane ($C_3$), and nitrogen ($N_2$) were selected as mixed refrigerants. Using the process model, optimum composition of refrigerants mixture was determined via mixture design and central composite design to produce minimum energy consumption. As a result, it was confirmed that energy consumption is reduced down to 11.3% comparing to existing design. It was also compared with heat effectiveness through temperature profile of MCHE (main cryogenic heat exchanger).

• Journal of the Korean Institute of Gas
• /
• v.23 no.1
• /
• pp.1-11
• /
• 2019

The Korean government has tried to introduce pipeline natural gas from Russia, instead of liquefied natural gas from Middle East Asia since 1990s. While this energy cooperation in North East Asia has been discussed in real politics and academic societies, the previous studies have shown the limits on policy implication because they just suggest necessity and possess the problems of weak theoretical frameworks. Therefore, this study tries to analyze the motivations, conditions, and stages for energy cooperation in this region from the viewpoint of economic integration theory. As a result of analysis, these countries in North East Asia have only one motivation, namely economic interest. On the contrary, they have several conditions including real benefit, complementation in economic structures, and convergence in policy goals. In conclusion, this study suggests that low level cooperation such as preferential trade agreement in the field of natural gas is possible and necessary in North East Asia.

• Journal of the Korean Institute of Gas
• /
• v.15 no.6
• /
• pp.38-43
• /
• 2011

Natural gas liquefaction process runs under cryogenic condition, and it spends large amount of energy. Minimizing energy consumption of natural gas liquefaction process is an important issue because of its physical characteristics. Among many kinds of natural gas liquefaction processes, C3-MR(Propane Pre-cooled Mixed Refrigerant) process uses two kind of refrigerants. One is the propane as the pure refrigerant(PR) and the other is the mixed refrigerant(MR). In this study, to find the optimal compressing level, propane cycle is simulated on different pressure level. The case study result shows relationship between energy consumption and pressure level. As a result, the conclusion is that at a higher pressure level, process consumes lower energy. At 5 pressure-levels, energy consumption is 23.7% lower than 3 pressure-levels.