• Journal of the Korean Society of Safety
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• v.29 no.2
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• pp.24-30
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• 2014

There have been controversies over whether explosion hazardous area(EHA) should be classified for facilities which use lighter-than-air gases such as city gas, hydrogen and ammonia. Two view points are confronting each other: an economic piont of view that these gases are lighter than air and disperse rapidly, hence do not form EHA upon release into the atmosphere, and a safety point of view that they are also inflammable gases, hence can form EHA although the extent is limited compared to heavy gases. But various standards such as KS, IEC, API, NFPA do not exclude light gases when classifying EHA and present examples of EHA for light gas facilities. This study calculates EHA using the hypothetical volume in the IEC code where the hole sizes required for the calculation were selected according to various nominal pipe sizes in such a way to conform to the EHA data in the API code and HSL. Then, 25 leakage scenarios were suggested for 5 different pipe sizes and 5 operating pressures that cover typical operating conditions of light gas facilities. The EHA for the minimum leakage scenario(25 mm pipe, 0.01MPa pressure) was found to correspond to a hypothetical volume larger than 0.1 $m^3$(medium-level ventilation). This confirms the validity of classifying EHA for facilities using lighter-than-air gases. Finally, a computer program called HACPL was developed for easy use by light gas facilities that classifies EHA according to operating pressures and pipe sizes.

• Journal of the Korea Society for Simulation
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• v.7 no.2
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• pp.17-32
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• 1998

The flow fields in Gas Bubble Driven Circulation Systems were numerically analyzed. In various gas flow rate and bubble size, the flow characteristics were predicted. Eulerian-Eulerian approach was used for the formulation of both the continuous and dispersed phases. The modification of the general purpose computer program PHOENICS code was employed to predict the mean flow fields, turbulent characteristics, gas dispersion, volume fraction. The predicted shows very satisfactory agreement with experimental results for all regions of ladle. The results are of interest in the design and operation of wide variety of material processing.

• Journal of the Korean Institute of Gas
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• v.18 no.6
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• pp.40-44
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• 2014

In this study, it is analyzed that a change in the shape of small propane containers made of STS304 when increasing of internal pressure. When internal pressure of a small propane container increased, bottom of end plate is convexly changed. This test is applied to a water bath pressure test to analyze the characteristics of the container. Water bath is able to analyze relationship between internal pressure and volume. In result, shape change section is confirmed because bottom of end plate is convexly changed. In addition, this section tend to decrease internal pressure because a volume increment increase out of proportion to pressure. The results of this study are expected to contribute to improving the safety of the pressure vessel, as well as various small propane container.

• Journal of Environmental Science International
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• v.18 no.7
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• pp.747-754
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• 2009

In this study, which aims to estimate the volume of greenhouse gas emitted by road transportation vehicles in Changwon City, the emission rate was calculated on the basis of the actual traffic volume measured at major crossroads and compared with the results obtained from the methodology used to estimate the greenhouse gas emissions of road transportation provided in the IPCC 2006 GL guidelines (Tier 1, Tier 3). Analysis of the results of the comparison showed that the Tier 1 methodology, which was applied in the estimation of the rate of greenhouse gas emissions, carries a high probability of underestimation, while the Tier 3 methodology carries a relatively high probability of overestimation. Therefore, when considering the assignment of permissible rates of emission to local governments, the application of the methodology, i.e. whether one uses Tier 1 or Tier 3, may result in a large difference in the rate of allowable emissions. It is suggested that a method based on the actual volume of traffic would be the most reasonable one with regard to the development of a realistic plan.

• Bulletin of the Korean Chemical Society
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• v.35 no.10
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• pp.2995-3000
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• 2014

A sensitive concentration method utilising modified gas-purge microsyringe extraction (GP-MSE) was developed. Concentration (reduction in volume) to a microlitre volume was achieved. PAHs were utilised as semivolatile analytes to optimise the various parameters that affect the concentration efficiency. The injection rate and temperature were the key factors that affected the concentration efficiency. An efficient concentration (75.0-96.1%) of PAHs was obtained under the optimised conditions. The method exhibited good reproducibility (RSD values that ranged from 1.5 to 9.0%). The GP-MSE concentration method enhances the volume reduction (concentration factor), leading to a low method detection limit ($0.5-15ngL^{-1}$). Furthermore, this method offers the advantage of small-volume sampling, enabling even the detection of diurnal hourly changes in the concentration of PAHs in ambient air. Utilising this method in combination with GC-MS, the diurnal hourly flux of PAHs from the gas phase of ambient air was measured. Indeed, the proposed technique is a simple, fast, low-cost and environmentally friendly.

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.2
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• pp.57-66
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• 2014

The leachate recirculation anaerobic digestion system has the advantage of stable methane gas generation compared with existing one phase systems. In this study, an anaerobic digestion system fed with source separated food waste from school cafeteria was studied with different food waste/inoculum anaerobic sludge volume ratios (8:2, 3:7, 2:8). From this study, leachate recirculation anaerobic reactor with food waste/inoculum anaerobic sludge volume ratio of 2:8 that is 9 gVS/L of OLR(Organic Loading Rate) had the highest gas production. Also this anaerobic reactor showed daily decrease of H2S and NH3 contents in produced gas. Average biogas yield was 1.395 m3 Biogas/kg VS added. Other anaerobic reactors with food waste/inoculum anaerobic sludge volume ratio of 8:2 and 3:7 stopped methane gas production.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.3
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• pp.380-383
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• 2003

The gas dilution technique was used to evaluate the possibility of estimating the volume of gaseous phase in the rumen from its composition in sheep given rice whole crop silage (RWS) or dent corn silage (DCS) at a level of maintenance (M) or 2 M, and in the course of fasting. The rumen gas composition was determined at 2 and 7.5 h after morning feeding. Nitrogen gas was injected by using an airtight syringe into the rumen immediately after collecting the rumen gas sample as a control. Then rumen gas samples were collected at 5, 10, 20, 40 and 60 min. after injection. Dry-matter intakes were $42g/kg^{0.75}$ and $57g/kg^{0.75}$ for DCS, and $36g/kg^{0.75}$ and $59g/kg^{0.75}$ for RWS, at 1 M and 2 M levels, respectively. Animals ingested both silages about 20% less than expected at 2 M level. The rumen gas composition did not differ significantly between 2 h and 7.5 h after feeding except for $N_2$. Content of $CO_2$ in gas composition was significantly higher at 2 M level than at 1 M (p<0.05) for both RWS and DCS, whereas $CH_4$ showed no significant difference between feeding levels. At both feeding levels, $CO_2$ showed a higher (p<0.05) percentage in DCS than RWS. A dilution technique by using $N_2$ injection is not appropriate for the determination of gas production in vivo, unless the rate of rumen gas turnover is considered. Changes in composition at fasting indicate that the rumen fermentation may reach the lowest level after 72 h fasting for sheep given silage as their sole diet.

• Journal of the Korean Institute of Gas
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• v.19 no.5
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• pp.98-103
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• 2015

Liquefied petroleum gas can be charged up to 85% of cylinder volume by enforcement regulations of safety control and business of liquefied petroleum gas act. The charged mass by enforcement regulations is considered by liquid expansion of internal liquefied petroleum gas at $65^{\circ}C$. But the temperature of liquid would not be suspended under $65^{\circ}C$ in a cylinder or portable vessel at certain situation. In the thermodynamics view point, the cylinder can be exposed to high pressure by liquid expansion. Consequently, it can be possible to potential risk such as physical explosion. Hence, this paper will offer a method of estimated internal pressure by liquid expansion at critical state in the closed system. Also, the structural factor which is given rise to volume increasement of cylinder is offered by experiment. This paper is expected as crucial reference for a cylinder design of liquefied petroleum gas.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.2
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• pp.230-234
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• 2010

Hydrox gas which is the mixed gas of hydrogen and oxygen gained fromwater electrolysis is one of the new clean energy sources and thus is researched and commercialized actively. Especially, it can be replaced the fossil energy and shows the better quality compared to the conventional energy such as LPG or acetylene gas. The mixed gas of hydrogen and oxygen is gained from water electrolysis reaction. It has constant volume ratio 2:1 of hydrogen and oxygen, and it is used as a source of thermal energy by combustion reaction. Further, hydrox gas is nearly a mixed ideal gas combusting itself completely and its combustion shows anunique characteristics of implosion. In this study, temperature rise effects on hydrox gas content through mixed combustion test of kerosene and hydrox gas and LPG and hydrox gas are investigated. it is also confirmed that economy of mixed combustion of hydrox gas as effective energy is fairly probable.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.8
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• pp.743-752
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• 2013

This is the second paper on the combustion characteristics of landfill gas in a constant volume combustion chamber for a large displacement volume commercial engine, and it discusses the combustion process on the basis of pressure measurements. The results show that the bimodal peak pressure phenomenon, which is caused by the interaction of the heat release and the heat transfer, is more apparent as the mixtures are more favorable to combustion, and the magnitudes of the pressures depend on the unburned fraction. In addition, there exist four main inflection points during heat release owing to variations in the heat transfer area related to flame propagation from the ignition point. Furthermore, the number of inflection points increases as the mixture quality worsens because of the extended burn duration. Consequently, the sophisticated interactions between the heat transfer area changing pattern due to flame propagation and transfer duration might cause very peculiar heat release patterns.