• Journal of the Korean Institute of Gas
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• v.5 no.2 s.14
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• pp.52-61
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• 2001

Cryogenic LNG(Liquefied Natural Gas) which is stored in the cylindrical storage tanks of $100,000m^3$ has very complex flow phenomena and the changes of thermal properties with exterior conditions and operation modes. These complex thermofluid behaviors are affected by the storage, exterior conditions of LNG, design specifications and heat transfer characteristics of tanks. Also, those have influence on the stable storage and supply of LNG in the storage tanks. Thus this study peformed the analysis on the 2-D heat transfer of the tank with exterior conditions, on the Cool Down Process in order to cool down the LNG Storage Tank at the initial normal state, and on the Filling Process considered for incoming and rising of LNG. The analysis on the Mixing LNG Storage was studied too. At last, the visualized program on the complex thermofluidodynamic analysis was developed on the basis of the above analyses. The development of this program becomes to be used to the basic design of the commercial tanks as well as to assure technical skill of the analysis on the thermal stability of the stored LNG in the LNG Storage Tank.

• Journal of the Korean Institute of Gas
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• v.11 no.1 s.34
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• pp.23-28
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• 2007

This paper presents an experimental investigation on the sealing defects and cracks of O-rings and a valve packing of a gas valve for a LPG cylinder. O-ring in which stops a gas leakage of a liquefied petroleum gas is very important for a LPG valve safety. Valve packing is to open and close a gas flow port for supplying and charging a LPG fuel. The sealing performance of two sealing units ism related to the leak safety and long lift of a gas valve. The investigated results show that most of O-rings was failed due to a circumferential crack in which is caused by partial press bonding failure near the partition zone and an excess compression rate. Some of the O-ring failure was originated by an extrusion of an excessive leak pressure of a LP gas. Thus, this paper strongly recommends a tight quality control and a safety guarantee system of O-rings and valve packing to guarantee a leak safety and to extend a service lift of a gas valve. At the end, a warranty policy of the sealing units should be adopted for increasing a product quality and safety of a gas valve.

• Journal of the Korean Institute of Gas
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• v.22 no.6
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• pp.59-64
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• 2018

As part of measures to reduce fine dust, the government is promoting a project to convert the fuel of Yard Tractors(YT, tractors operated at ports), from diesel to LNG (Liquefied Natural Gas). While a port having a small number of yard tractors, it is not proper to construct a stationary LNG fueling station and supply LNG to YT due to a problem of BOG (Boil off gas) generation. Therefore, it is necessary to make a regulation and a standard on mobile LNG YT refueling station installation and inspection as an alternative. In this study, we have investigated domestic and foreign mobile LNG refueling cases and refueling standards, including the USA and Europe. In addition, we have suggested the risk reduction method according to the cause after investigation of the cause of LNG accidents. And last, based on the proposed risk reduction measures, we have proposed an amendment to the Regulation of the Urban Gas Business Law in Korea. The proposed mobile LNG YT refueling amendment of the Regulation includes ; maintenance of the safety distance from the protection facility, installation of an interlock device to prevent refueling in places other than the authorized place, installation of the identification system through biometrics, separation of the tank lorry and tow vehicle before refueling, checking the wheel fixed status of tank lorry before refueling, construction of the impounding area, safety measures before, during and after refueling, etc. The safety standards proposed in this study could be used as a reference in establishing standards for mobile LNG vehicle refueling in the near future.

• 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.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.617-626
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• 2019

This study analyzes the optimal location of gas detectors through the gas dispersion in a cargo compressor room of a 174K LNG carrier equipped with high-pressure cargo handling equipment; in addition, we propose a reasonable method for determining the safety regulations specified in the new International Code of the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC). To conduct an LNG gas dispersion simulation in the cargo compressor room-equipped with an ME-GI engine-of a 174 K LNG carrier, the geometry of the room as well as the equipment and piping, are designed using the same 3D size at a 1-to-1 scale. Scenarios for a gas leak were examined under high pressure of 305 bar and low pressure of 1 bar. The pinhole sizes for high pressure are 4.5, 5.0, and 5.6mm, and for low pressure are 100 and 140 mm. The results demonstrate that the cargo compressor room will not pose a serious risk with respect to the flammable gas concentration as verified by a ventilation assessment for a 5.6 mm pinhole for a high-pressure leak under gas rupture conditions, and a low-pressure leak of 100 and 140 mm with different pinhole sizes. However, it was confirmed that the actual location of the gas detection sensors in a cargo compressor room, according to the new IGC code, should be moved to other points, and an analysis of the virtual monitor points through a computational fluid dynamics (CFD) simulation.

• Korean Chemical Engineering Research
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• v.62 no.1
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• pp.70-79
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• 2024

Raman analyzer is an analytical technique that utilizes the "Raman effect", which occurs when light is scattered by the inherent vibrations of molecules. It is used for molecular identification and composition analysis. In the natural gas industry, it is widely used in bunkering and tank lorry fields in addition to LNG export and import terminals. In this study, a LNG-specific Raman analyzer was installed and operated under actual field conditions to analyze the composition and principal properties (calorific value, reference density, etc.) of LNG. The measured LNG composition and calorific value were compared with those obtained by conventional gas chromatograph that are currently in operation and validated. The test results showed that the Raman analyzer provided rapid and stable measurements of LNG composition and calorific value. When comparing the calorific value, which serves as the basis for LNG transactions, with the results from conventional gas chromatograph, the Raman analyzer met the acceptable error criteria. Furthermore, the measurement results obtained in this study satisfied the accuracy criteria of relevant international standards (ASTM D7940-14) and demonstrated similar outcomes compared to large-scale international demonstration cases.

• Journal of the Korean Institute of Gas
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• v.14 no.2
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• pp.1-6
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• 2010

The strength safety of high pressure gas cylinder has been analyzed by using a finite element method. In this study, the internal gas pressures of a steel bombe include a service charging pressure of $9kg/cm^2$, high limit charging pressure of $18.6kg/cm^2$, high limit of safety valve operation pressure $24.5kg/cm^2$, and hydraulic testing pressure of $34.5kg/cm^2$. The computed FEM results indicate that the strength safety for a service charging pressure of $9kg/cm^2$ and high limit charging pressure of $18.6kg/cm^2$ is safe because the stress of a gas cylinder is within yield strength of steel. But the stress for a hydraulic testing pressure of $34.5kg/cm^2$ sufficiently exceeds the yield strength and remains under the tensile strength. If the hydraulic testing pressures frequently apply to the gas cylinder, the bombe may be fractured because a fatigue residual stress is accumulated on the lower round end plate due to a plastic deformation. The computed results show that the concentrated force in which is applied on a skirt zone does not affect to the lower round end plate, and the most weak zone of a bombe is a middle part of a lower round end plate between a bombe body and a skirt for a gas pressure. Thus, the FEM results show that the profile of a lower round end plate is an important design parameter of a high pressure gas cylinder.

• Journal of the Korean Institute of Gas
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• v.20 no.6
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• pp.9-15
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• 2016

Liquefied petroleum gas (LPG) and compressed natural gas (CNG) are often used as fuel for vehicles because they are clean alternative gas fuels. CNG, as a low-carbon fuel, can contribute to the reduction of greenhouse gas emissions. LPG is often used as fuel for taxis because the performance is almost the same as that of gasoline but the price is lower. In the present study, the exhaust gas and the particle number (PN) of particulate matter, which is a recent environmental issue, were compared between LPG and CNG for the same vehicle. A chassis dynamometer was used to conduct the test according to the Federal Test Procedure (FTP)-75 and Worldwide harmonized Light-duty vehicle Test Procedure (WLTC) modes. The PN values of discharged particles having sizes of 5 nm or larger and 23 nm or larger were measured using two condensation particle counters (CPC). The ratio of carbon dioxide was high in the exhaust gas from the LPG vehicle; the ratio of methane was high in the exhaust gas from the CNG vehicle. The PN values of the emitted particles from the two fuels were similar. The PN values of particles having sizes of 23 nm or smaller were high in the high-speed WLTC mode.

• Applied Chemistry for Engineering
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• v.17 no.4
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• pp.361-368
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• 2006

The purpose of this study is to invent the preparation technique of the foam-floater used as a level gauge of liquefied petroleum gas (LPG) tank under high pressure, which has not only closed pores but also has under 5 wt% changingrate in case of depositing 72 h in room-temperature LPG. In pressure-resistance and deposition experiment, the prepared foam-floaters with different sulfur (325 Mesh and 400 Mesh) and foaming agent (dinitrosopentamethylenetetramin; DPT and azodicarbonamide; AC) had a marginal difference in its weight changing-rate. However, the prepared floater with sulfur 400 Mesh and the foaming agent AC had smaller pores and higher closed pore-rate. Under $50kg_f/cm^3$ hydraulic pressure, the floater with medium thermal (MT) carbon showed a lower weight changing-rate than semi reinforcing furnace (SRF) carbon. Providing a post-treatment to the prepared floater, the hardness and the pressure-resistance of the inner pore-wall of floater were increased. Prepared floaters having a specific gravity below 0.30 were distorted and broken, and other floaters with a specific gravity above 0.35 were not useful as a floater because of the low buoyancy. Therefore, it was considered that the floaters with a specific gravity between 0.3~0.35 are the most useful as a floater under $50kg_f/cm^3$ pressure-resistance.

• Journal of the Korean Applied Science and Technology
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• v.35 no.3
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• pp.816-825
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• 2018

Recently, it was emerged to need the necessity of LPG residues management due to the finding some substances such as rust. This study is performed to investigate the characteristics of LPG residues in the production and distribution stage of LPG. For the qualitative analysis of LPG residues, it was operated to be set up the analysis conditions(the flow rate, etc) of GC-MS and was performed to analyze the component of LPG residues. From the analysis result using GC-MS, it was shown that the component of LPG residues was turned out the plasticizer to be used in the rubber manufacturing process. The inorganic components of LPG residues were analyzed using ICP-OES. At the results of inorganic analysis, it was shown that the Si element was detected, which was presumably derived from defoamers used mainly in the LPG production. Also, the P and Zn element, which are estimated to be components of grease additives used for filling facilities, were also partially detected. No trace of rusting was detected in the LPG residues in the production and distribution stages analyzed in this study. But, as plasticizers and grease additives can affect to the LPG fuel system in vehicles, it will be necessary to use the proper quality of rubber and to expand the use of low boiling grease additives.