• Title/Summary/Keyword: conventional natural gas

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Simulation of a 50 ㎾ Phosphoric Acid Fuel Cell System Using Natural Gas (천연가스를 사용하는 50 ㎾ 인산형 연료전지 시스템의 전산모사)

  • 서정원;김성준;설용건;이태희
    • Journal of Energy Engineering
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    • v.2 no.1
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    • pp.75-82
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    • 1993
  • A 50 ㎾ phosphoric acid fuel cell(PAFC) system using natural gas was simulated for steady state with the commercial software, ASPEN PLUS. The USER block and the FORTRAN block were prepared to simulate the cell. The changes of hydrogen yield according to the variation of several operating conditions were examined and the operating conditions to maximize hydrogen yield were obtained. The simulation results agree with the real data, which can be used to prepare the basic process data and the optimal conditions for the domestic commercial fuel cell system. H$_2$utilization rate over 50% should be maintained to achieve the efficiency of the conventional electricity generation. Energy consumption can be reduced by utilizing the heat released from the reformer and the cell which are operated at high temperatures.

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Treatment of Halogen Gases, BCl3 and CF4, used in Semiconductor Process by Using Inorganic Gas Adsorption Agents (무기흡착제를 이용한 반도체 공정에서 사용되는 할로겐 가스 (BCl3, CF4) 의 처리 및 측정에 관한 연구)

  • Lim, H.B.;Hwang, Cheong-Soo;Park, Jeong-Jun
    • Analytical Science and Technology
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    • v.16 no.5
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    • pp.368-374
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    • 2003
  • Halogen gases such as $BCl_3$ and $CF_4$ are among the most problematic gases used in semiconductor process. They raise serious environmental and health problems due to their extreme toxicity. This study is to develop a method to effectively remove those gases during the process by using various types of inorganic gas adsorption agents such as zeolite A, modified AgA zeolite, ZnO, and $AgMnO_3$, which have not been attempted in the conventional methods. The removal efficiencies of the gases were both qualitatively and quantitatively measured by a FT-IR spectrophotometer. The whole device for the measurement has been designed and built in our lab. The removal efficiencies of the gases were compared between those used resins. The experimental result revealed that ZnO showed the best removal efficiency for BCl3 gas that had removed 0.094 g per 1 g of the resin used. For $CF_4$ gas, none of the solid resins was able to remove the gas effectively. However, liquid $CHCl_3$ showed some removal ability of the $CF_4$ gas.

Boil-Off Gas Reliquefaction System for LNG Carriers with BOG-BOG Heat Exchange (BOG 내부 열교환을 이용한 LNG 선박용 Boil-Off Gas 재액화 시스템)

  • Lee, Yoon-Pyo;Shin, You-Hwan;Lee, Sang-Hoon;Kim, Kwang-Ho
    • Journal of the Society of Naval Architects of Korea
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    • v.46 no.4
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    • pp.444-451
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    • 2009
  • The price increase of natural resources and the worldwide growth of LNG demand led to save the waste of Boil-Off Gas evaporating from cargo tanks of LNG carriers during navigation. As one of the efforts, a BOG reliquefaction system with BOG-to-BOG heat exchanging method was newly devised. This study was also discussed on the process details such as some features and advantages including comparisons with conventional BOG reliquefaction system, non BOG-BOG heat exchange type. The thermodynamic analysis for the system were also performed. Through the cycle simulation, the process efficiency of the BOG reliquefaction system BOG-BOG heat exchange was estimated to be increased up to 21%.

An Experimental and Numerical Analysis on Performance Comparison of a Trigeneration Desiccant System and Conventional Air-conditioning System (Trigeneration 제습공조시스템과 일반공조시스템의 성능 비교 실험 및 수치해석)

  • Kim, Hyoung-Tae;Chae, Jungmin;Cho, Young-Ah;Park, So-jin;Song, Geun-Soo
    • Journal of the Korean Institute of Gas
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    • v.22 no.3
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    • pp.32-37
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    • 2018
  • Recently, the distributed power generation market using natural gas is expected to expand gradually according to the government's future energy conversion policy. Distributed power generation means small power generation source near the power demand site, which has the advantage of reducing the construction costs of the transmission and distribution infrastructure, operating cost and power loss. A typical example of distributed generation using natural gas is the trigeneration system. In this study, we conducted a basic study on the performance analysis of trigeneration desiccant system for dehumidifying / cooling / heating in the air conditioner room by using the cold and engine waste heat energy generated in the trigeneration system. It shows that the system efficiency increases and the energy consumption decreases as the temperature difference between the inlet and outlet of the trigeneration system increases compared with the general air conditioning system.

A Study on the Knocking Characteristics with Various Excess Air Ratio in a HCNG Engine (HCNG 엔진의 공기과잉율 변화에 따른 노킹 특성에 관한 연구)

  • Lim, Gihun;Park, Cheolwoong;Lee, Sungwon;Choi, Young;Kim, Changgi;Lee, Janghee
    • Journal of the Korean Institute of Gas
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    • v.17 no.1
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    • pp.7-12
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    • 2013
  • As emission regulation for vehicle has been reinforced, many researches carried out for HCNG(hydrogen-natural gas blends) fuel to the conventional compressed natural gas (CNG) engine. However, abnormal combustion such as backfire, pre-ignition or knocking can be caused due to high combustion speed of hydrogen and it can result in over heating of engine or reduction of thermal efficiency and power output. In the present study, improvement of combustion performance was observed with HCNG fuel since it can extend a flammability limit. Knocking characteristics for CNG and HCNG fuel were investigated. Feasibility of HCNG fuel was evaluated by checking the knock margin according to excess air ratio. The operation of engine with HCNG was stable at minimum advance for best torque(MBT) spark timing and knock phenomena were not detected. However, it is necessary to prepare higher knock tendency since possibility of knock is higher with HCNG fuel.

Comparative Study on the Thermal Insulation of Membrane LNG CCS by Heat Transfer Analysis (열전달 해석을 이용한 멤브레인형 LNG 화물창의 단열구조 성능비교)

  • Hwang, Se-Yun;Lee, Jang-Hyun
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.29 no.1
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    • pp.53-60
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    • 2016
  • This study discusses the thermal insulation capacity of variant of NO96 LNG (liquefied natural gas) cargo containment insulation system. Changing the insulation materials and the insulation layers of conventional GTT NO96 containment system, The thermal resistance and BOR(boil off rate) caused by the heat transfer between cryogenic and environmental temperature is discussed. Therefore, thermal analysis of LNG CCS(cargo containment system) is carried out to determine the insulation capabilities. Also, BOR is evaluated in terms of the total amount of heat invaded into CCS(cargo containment system). Variant of NO96 CCS such as NO96, NO96GW and NO96L3 membrane type during laden voyage is selected for the comparative study. Finite element model for heat transfer analysis is conducted by employing the equivalent thermal resistance model to simplify the complex insulation layers. Finally the results for each variant model are relatively compared and discussed to minimize the BOR.

Cryogenic Mechanical Characteristics of Laminated Plywood for LNG Carrier Insulation System (LNG운반선 방열시스템에 적용되는 적층형 플라이우드의 극저온 기계적 특성 분석)

  • Kim, Jeong-Hyeon;Park, Doo-Hwan;Choi, Sung-Woong;Lee, Jae-Myung
    • Journal of Ocean Engineering and Technology
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    • v.31 no.3
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    • pp.241-247
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    • 2017
  • Plywood, which is created by bonding an odd number of thin veneers perpendicular to the grain orientation of an adjacent layer, was developed to supplement the weak points such as contraction and expansion of conventional wood materials. With structural merits such as strength, durability, and good absorption against impact loads, plywood has been adopted as a structural material in the insulation system of a membrane type liquefied natural gas (LNG) carrier. In the present study, as an attempt to resolve recent failure problems with plywood in an LNG insulation system, conventional PF (phenolic-formaldehyde) resin plywood and its alternative MUF (melamine-urea-formaldehyde) resin bonded plywood were investigated by performing material bending tests at ambient ($20^{\circ}C$) and cryogenic ($-163^{\circ}C$) temperatures to understand the resin and grain effects on the mechanical behavior of the plywood. In addition, the failure characteristics of the plywood were investigated with regard to the grain orientation and testing temperature.

Development of Simulation Model for PEMFC Hybrid Excavator (연료전지 시스템을 적용한 하이브리드 굴삭기 해석 모델 개발)

  • Lee, Se Young
    • Journal of Drive and Control
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    • v.16 no.3
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    • pp.16-22
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    • 2019
  • Due to the rise in energy consumption and natural resource prices, the demand to improve energy efficiency in the construction machine has been highlighted. Even though many researchers have contributed to the development of the technology, CO2 gas emissions of heavy machinery remains high. One of the most significant problems of the novel excavator with internal combustion engines is the emission of harmful gas. To reduce emissions in the construction machine, it is necessary to replace the internal combustion engines with the alternative one. To overcome those problems, this paper focuses on the adoption of PEMFC hybrid engine for the excavator system. An internal combustion engine is replaced by new structures with fuel cell, battery and ultra capacitor. The proposed system has been designed and modeled using Simcenter Amesim software and compared with the conventional one through simulation results.

Analysis of CO2 Emission Depending on Hydrogen Production Methods in Korea (국내 수소 생산에 따른 CO2 발생량 분석)

  • Han, Ja-Ryoung;Park, Jinmo;Kim, Yohan;Lee, Young Chul;Kim, Hyoung Sik
    • Journal of the Korean Institute of Gas
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    • v.23 no.2
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    • pp.1-8
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    • 2019
  • Because of environmental pollution problem, interests in hydrogen energy has been concentrating sharply. Especially in Korea, the market related with fuel cell vehicles and hydrogen refueling stations is increasing actively under the government-led. However, the actual contributions to environmental improvement effect of hydrogen energy is required to be evaluated with representing reality. In this sense, lots of conventional analyzing tools have some limitations to adapt in Korea's situation directly. It is caused by the differences of raw energy market between the US and Korea. That is, most of analytic tools are developed by representing energy market of the US, where can produce variety of raw feed energy sources. Therefore, in this paper, we propose mass balance based numerical analyzing method, which is suitable for the actual hydrogen production process in Korea for exact evaluation of $CO_2$ emission amount in this country. Using proposed method, we has demonstrated reformed hydrogen from natural gas, LPG and naphtha, electrolysis-based hydrogen, and COG-based hydrogen. Furthermore, with the comparison of GREET program analysis results, robustness of numerical analysis method is demonstrated.

Impact of pore fluid heterogeneities on angle-dependent reflectivity in poroelastic layers: A study driven by seismic petrophysics

  • Ahmad, Mubasher;Ahmed, Nisar;Khalid, Perveiz;Badar, Muhammad A.;Akram, Sohail;Hussain, Mureed;Anwar, Muhammad A.;Mahmood, Azhar;Ali, Shahid;Rehman, Anees U.
    • Geomechanics and Engineering
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    • v.17 no.4
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    • pp.343-354
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    • 2019
  • The present study demonstrates the application of seismic petrophysics and amplitude versus angle (AVA) forward modeling to identify the reservoir fluids, discriminate their saturation levels and natural gas composition. Two case studies of the Lumshiwal Formation (mainly sandstone) of the Lower Cretaceous age have been studied from the Kohat Sub-basin and the Middle Indus Basin of Pakistan. The conventional angle-dependent reflection amplitudes such as P converted P ($R_{PP}$) and S ($R_{PS}$), S converted S ($R_{SS}$) and P ($R_{SP}$) and newly developed AVA attributes (${\Delta}R_{PP}$, ${\Delta}R_{PS}$, ${\Delta}R_{SS}$ and ${\Delta}R_{SP}$) are analyzed at different gas saturation levels in the reservoir rock. These attributes are generated by taking the differences between the water wet reflection coefficient and the reflection coefficient at unknown gas saturation. Intercept (A) and gradient (B) attributes are also computed and cross-plotted at different gas compositions and gas/water scenarios to define the AVO class of reservoir sands. The numerical simulation reveals that ${\Delta}R_{PP}$, ${\Delta}R_{PS}$, ${\Delta}R_{SS}$ and ${\Delta}R_{SP}$ are good indicators and able to distinguish low and high gas saturation with a high level of confidence as compared to conventional reflection amplitudes such as P-P, P-S, S-S and S-P. In A-B cross-plots, the gas lines move towards the fluid (wet) lines as the proportion of heavier gases increase in the Lumshiwal Sands. Because of the upper contacts with different sedimentary rocks (Shale/Limestone) in both wells, the same reservoir sand exhibits different response similar to AVO classes like class I and class IV. This study will help to analyze gas sands by using amplitude based attributes as direct gas indicators in further gas drilling wells in clastic successions.