• Journal of the Korean Institute of Gas
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• v.14 no.1
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• pp.15-20
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• 2010

The interest on the utilization of landfill gases and biogases for energy production has been increasing due to environment concerns and global warming caused by burning fossil fuels, renewable nature of these gases. Using those synthesis gases to generate energy with engine encourages more efficient collection reducing emissions into the atmosphere and generates revenues for the operators. However the lower calorific value of synthesis gases than that of LPG or CNG affects the combustion stability and power output. Thus it becomes necessary to address disadvantages involved by studying synthesis gases in technological perspective. This paper discussed synthesis gas as a fuel for 60kW dual-fuel engine to produce power in an effective way. The methane diluted with $N_2$ was used as a fuel and developed ECU and injector driver facilitated the investigations with diesel fuel.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.1
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• pp.73-84
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• 2014

The present paper includes recent research works on the estimation of physical properties like equivalence ratio and heat release rate of flame through chemiluminescence measurement. Modern combustion devices require a precise control to increase combustion stability as well as to suppress pollutant emissions. The determination of combustion characteristics from chemiluminescence provides practical advantages over other techniques. However, the technique is dependent on equivalence ratio, combustion pressure, inlet temperature, turbulent intensity and fuel type. The intensity ratio of $OH^*$ and $CH^*$ has a strong relation with an equivalence ratio for methane/air premixed flames. The global measurement of chemiluminescence is accepted as a good indicator for a global heat release rate.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.6
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• pp.814-819
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• 2011

An Oxy-fuel combustion has been studied in order to reduce exhaust emissions and fuel consumption. The flow and flame behaviors are analyzed with focal length variation in one-focussing oxygen burner introduced in this study. Oxygen is supplied into the center of the nozzle, methane fuel is into the outer nozzle of the center, and then oxygen is again supplied into the outer of the fuel nozzle. The test conditions are 5 focal lengths of 100mm to 500mm. The mixing behaviors and temperature distributions are analyzed. The result shows that the shorter the focal length is, the longer the mixing length becomes, and the flame width and length are the biggest in the case of 300mm.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.1
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• pp.77-87
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• 2014

In this study, an experimental approach to measure a suite of low weight hydrocarbons was investigated with an emphasis on ethylene (EL) along with many others (ethane (EA), propane (PA), propylene (PL), n-butane (BA), acetylene (AL), methyl acetylene (ML)). Their concentrations were quantified using GC-FID system equipped with thermal desorption (TD) system. The TD-based analysis was conducted using both Link Tube/Thermal Desorber (LT/TD) method and Modified Injection through a Thermal Desorption (MITD) method. The results of these analyses were evaluated in a number of respects. The system allowed the detection of all compounds except methane with the mean response factor (RF) of 10.28 (EA) to 11.94 (PL). The method detection limits of target compounds were seen in the range of 0.027 (ML) to 0.146 ng (BA). The emission flux of some environmental samples (fruits), when measured using a small flux chamber system, fell in the range of 0.14 (AL: Kiwi) to $181ng{\cdot}g^{-1}{\cdot}hr^{-1}$ (EL: Apple Peel). The results of this study confirm that the experimental approach developed in this study allows to accurately measure emissions of low weight hydrocarbons (LWHC) like ethylene from various natural and man-made source processes.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.12
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• pp.587-613
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• 1999

Environmental problems such as global climate change, depletion, ocean and air pollution, and resource degradation-compounded by an expanding world population-respect no border and threaten the health, prosperity and jobs of all mankind. Our efforts to promote democracy, free trade, and stability in the world will fall short unless people have a livable environment. We have an enormous stake in the management of the world's resources. By increasing demand for timber, natural gas, coal and consumer's goods have destroyed the grounds for living. Greenhouse gas emissions anywhere in the world have threatened coastal communities, and then changed the Earth's climate system. The burning of coal, oil, and other fossil fuels is increasing substantially the concentration of heat-trapping gasses such as carbon dioxide, methane, and nitrous oxide in our air. The earth's temperature and sea levels are rising as a result. Since 1972 there has been a marked growth in the number and scope of environmental treaties. In particular, after the 1992 Rio Conference, international legal instruments became more concentrated on addressing environment within the context of sustainable development and incorporated a number of new concepts and innovative approaches. A preliminary analysis of recent conventions and in particular those associated with the Rio Conference indicates various ideas, concepts and principles which have come to the fore including sustainable development, equity, common concern of humankind, common but differentiated responsibilities and global partnership. However, international trade also has an environmental impact which must be minimized or countered. Positive measures are to be preferred to achieve environmental goals, but where trade provisions are necessary, they should be appropriately used within environmental conventions to facilitate the reduction and limitation of the negative impacts of trade and to enhance the complementarity of the multilateral trade regime with the imperatives of environmental protection, in the interests of environmental protection and sustainable development generally. The international community has to recognize and endorse this need to achieve complementarity between trade and environment issues.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.5
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• pp.449-456
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• 2010

The HCCI engine is a prospective internal combustion engine with which high diesel-like efficiencies and very low NOx and particulate emissions can be achieved. However, several technical issues must be resolved before HCCI engines can be used for different applications. One of the issues concerning the HCCI engine is that the operating range of this engine is limited by the rapid pressure rise caused by the release of excessive heat. This heat release is because of the self-accelerated combustion reaction occurring in the engine and the resulting engine knock in the high-load region. The purpose of this study is to evaluate the role of thermal stratification and fuel stratification in reducing the pressure rise rate in an HCCI engine. The concentrations of NOx and CO in the exhaust gas are also evaluated to confirm combustion completeness and NOx emission. The computation is carried out with the help of a multizone code, by using the information on the detailed chemical kinetics and the effect of thermal and fuel stratification on the onset of ignition and rate of combustion. The engine is fueled with dimethyl ether (DME), which allows heat release to occur in two stages, as opposed to methane, which allows for heat release in a single stage.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.4
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• pp.309-315
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• 2012

Catalytic combustion is generally accepted as one of the environmentally preferred alternatives for heat and power from fossil fuels, as it has the advantage of stable combustion under very lean conditions with such low emissions as UHC, CO, and NOx. In this work, therefore, comparative numerical studies on the catalytic combustion behaviors over Pd-based catalysts have been conducted with the gaseous $CH_4$, $C_2H_6$, and $C_3H_8$. In the following, after introducing the governing equations with 1D channel and Langmuir-Hinshelwood models, numerical investigations on the catalyst performance are conducted by changing such various parameters as inlet temperature, excess air ratio, and space velocity. The numerical results show that outlet temperature and conversion of $C_3H_8$ are highest among others because of its chemical structure and reactivity.

• Journal of Environmental Policy
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• v.4 no.1
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• pp.69-91
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• 2005

In order to accurately evaluate the distribution and emission characteristics of volatile organic compounds(VOCs) produced in the landfill environment, we conducted a series of field campaign to measure VOC emissions from a total of eight landfill sites located all across the Korean Peninsula. During the field measurements made from Sept. 2000 to Dec. 2004, we investigated VOC emission characteristics from 1 large scale, 5 mid scale, and 2 small scale landfill sites. The results from our 4-years study is used to provide valuable information for the management of landfill facilities in Korea. If annual emission rates of VOC are compared in terms of toluene, the magnitude of its emission differed between the closed and active landfills. Whereas closed landfills show emission rates from a few tens to 500g/yr, those of active ones were recorded as 1,000 to 40,000g/yr.

• Korean Chemical Engineering Research
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• v.59 no.3
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• pp.435-442
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• 2021

Mn-added Barium hexaaluminates were manufactured by homogeneous precipitation method using Urea. The effects of water wash and dry temperature were analyzed by thermal weight analysis, X-ray diffraction analysis, and scanning electron microscopy. Catalysts that went through the filtration step only produced pure hexaaluminate images compared to those that went through the water wash step. During the drying process, it seems that the remaining urea helps dehydration of the precursor and affects the phase shift of gibbsite to boehmite, which is easy to convert to pure hexaaluminate. The catalyst WO200 gave the best performance in the methane combustion reaction, and NOx was not emitted in the reaction for all catalysts. Hexaaluminates were found to affect reducing the highest CO emissions.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.773-779
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• 2021

CNG, which has recently been attracting attention as an alternative fuel in the transportation field to reduce emissions caused by global warming, is natural gas with abundant reserves and mainly composed of methane. Being in a gaseous state, natural gas requires the compression and liquefaction processes for transportation. Until now, general shut-off valves for liquid and gas piping have been developed in Korea, but there are few studies on shut-off valves for high pressures of about 200 bar. Currently, research on the flow analysis of valves is being actively conducted around the world. However, there are relatively many studies on large valves such as low-pressure valves or shipbuilding and marine, and the safety factor through structural analysis to check the structural integrity of the valve is checked at the design stage. Since it is necessary to have a fast response speed while minimizing pressure and speed loss due to flow change, basic research was conducted on the flow analysis of the valve to secure design data, and the numerical analysis was performed on high-pressure automatic shut-off valves applied to CNG refueling stations. After securing the basic valve shape through reverse engineering for advanced products, we compared the valve flow coefficient Cv coefficient with advanced products. As a result, it was found that the reverse engineering model was at the level of about 60%. However, we compared the Cv coefficient by modifying the reverse engineering model, and the result showed that it was improved to about 96%.