• 한국안전학회지
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• 제32권2호
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• pp.66-71
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• 2017

The autoignition temperature (AIT) is crucial combustible characteristics which need attention in chemical process that handle hazardous materials. The AIT, also to as minimum spontaneous ignition temperature(MSIT), is the lowest temperature of a hot surface at which the substance will spontaneously ignite without any obvious sources of ignition such as a spark or flame. The AIT may be used as combustion property to specify operating, storage, and materials handling procedures for process safety. This study measured the AITs of n-propanol+acetic acid system from ignition delay time(time lag) by using ASTM E659 apparatus. The AITs of n-propanol and acetic acid which constituted binary system were $435^{\circ}C$ and $212^{\circ}C$, respectively. The experimental AITs of n-propanol+acetic acid system were a good agreement with the calculated AITs by the proposed equations with a few A.A.D.(average absolute deviation). In the case of n-propanol and acetic acid system, the minimum autoignition temperature behavior (MAITB), which is lower than the lower AIT, is shown among the two pure substances constituting the mixture.

• 한국안전학회지
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• 제32권5호
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• pp.25-31
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• 2017

The flash point, explosion limits, autoignition temperature(AIT) are important combustible properties which need special concern in the chemical safety process that handle hazardous substances. For the evaluation of the flammable properties of n-butylacetate, this study was investigated the explosion limits of n-butylacetate in the reference data. The flash points, fire points and AIT by the ignition delay time of n-butylacetate were experimented. The lower flash points of n-butylacetate by using the Setaflash and Pensky-Martens closed-cup testers were $24^{\circ}C$ and $26^{\circ}C$, respectively. The flash points of n-butylacetate using the Tag and Cleveland open cup testers are measured $31^{\circ}C$ and $40^{\circ}C$, respectively. And the fire points of n-butylacetate by the Tag and Cleveland open cup testers were measured $32^{\circ}C$ and $41^{\circ}C$. The AIT of n-butylacetate measured by the ASTM 659E tester was measured as $411^{\circ}C$. The lower explosion limit of lower flash point $24^{\circ}C$, which was measured by the Setaflash tester, was calculated to be 1.40 vol%. Also, the upper explosion limit of upper flash point $67^{\circ}C$ the Setaflash tester was calculated to be 12.5 vol%.

• 한국기계가공학회지
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• 제16권4호
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• pp.89-96
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• 2017

A cable tray is a structure made of metal or a non-combustible material that supports cables in the electrical wiring of buildings. Cable trays should be developed to meet the various requirements of the construction site. In this study, a design system was developed to calculate the maximum support load and the maximum deflection according to the cross-sectional shape of the cable tray. The cross-sections of cable trays were modeled by combining linear and arc elements, and cross-sectional characteristics such as the 2nd moment of area were calculated. The distributed load and the concentrated load were applied to the cable tray using the Euler beam theory, and then the deflection profiles and maximum stress were calculated. To verify the developed system, deflection distributions and maximum stresses for two types of cable trays were calculated and compared. The maximum deflection and maximum stress errors calculated from the developed system were found to be less than 4% compared with numerical analysis results.

• 방사성폐기물학회지
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• 제2권3호
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• pp.175-180
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• 2004

In order to vitrify the combustible dry active waste (DAW) generated from Korean Nuclear Power Plants, a glass formulation development based on waste composition was performed. A borosilicate glass, DG-2, was formulated to vitrify the DAW in an induction cold crucible melter (CCM). The processability, product performance, and volume reduction effect of the candidate glass were evaluated using a computer code and were measured experimentally in the laboratory and CCM. The glass viscosity and electrical conductivity as the process parameters were in the desired ranges. Start-up and maintaining glass melt of the candidate glass were favorable in the CCM. The product of the glass product such as chemical durability, phase stability, and density was satisfactory. The vitrification process using the candidate glass was also evaluated assuming that it was operated as economically as possible.

• 한국자동차공학회논문집
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• 제12권5호
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• pp.32-39
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• 2004

HCCI (Homogeneous Charge Compression Ignition) combustion has a great advantage in reducing NOx (Nitrogen Oxides) and PM (Particulate Matter) by lowering the combustion temperature due to spontaneous ignitions at multiple sites in a very lean combustible mixture. However, it is difficult to make a diesel-fuelled HCCI possible because of a poor vaporability of the fuel. To resolve this problem, the two-stage injection strategy was introduced to promote the ignition of the extremely early injected fuel. The compression ratio and air-fuel ratio were found to affect not only the ignition, but also control the combustion phase without a need for the intake-heating or EGR (Exhaust Gas Recirculation). The ignition timing could be controlled even at a higher compression ratio with increased IMEP (Indicated Mean Effective Pressure). The NOx (Nitrogen Oxides) emission level could be reduced by more than 90 % compared with that in a conventional DI (Direct Injection) diesel combustion mode, but the increase of PM and HC (Hydrocarbon) emissions due to over-penetration of spray still needs to be resolved.

• 한국화재소방학회논문지
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• 제24권3호
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• pp.39-44
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• 2010

현재 열방출률을 측정하는 데 사용되고 있는 콘칼로리미터 법은 일정한 복사도 값을 가지고 실험한다. 하지만, 실물화재 시 가연물은 연소할 때 동일하지 않은 열선속을 방출한다. 본 연구에서는 일정 크기를 갖는 실내를 대상으로 FDS를 사용하여 실내 열선속 변화에 따른 연소특성을 분석하여 실내화재 시 온도 변화를 계산하여, 콘칼로리미터의 콘 히터에 유동적인 열선속을 적용하여 복사도에 반영하였다. 결과로 화재 성장기(Growth period) 및 감쇠기(Decline period)와 같은 복사도의 변화에 따라 실물화재에 근거한 PMMA의 열방출률을 얻을 수 있었다.

• 청정기술
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• 제24권2호
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• pp.119-126
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• 2018

This study introduced a treatment process that was developed to treat Indonesian low-rank coal with high-ash content, which has the same characteristics as residual coal from the biosolubilization process. The treatment process includes separation of ash, solid-liquid separation, pelletizing, and drying. To reduce the ash content, flotation was performed using 4-methyl-2-pentanol (MIBC) as frother, and kerosene, waste oil, and cashew nut shell liquid (CNSL) as collectors. The increasing amount of collector had an effect on combustible coal recovery and ash reduction. After flotation, a filter press, extruder, and an oven drier were used to make a dried coal pellet. Then another coal pellet was made using asphalt as a binder. The compressive strength and friability of the coal pellets were tested and compared.

• 한국수소및신에너지학회논문집
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• 제20권6호
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• pp.519-525
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• 2009

The catalytic steam reforming of woody biomass tar and soot to convert a synthetic gas containing hydrogen was investigated by using a bench-scale biomass gasification system. One commercial nickel-based catalyst, Katalco 46-6Q, and two different kinds of natural minerals, dolomite and olivine, were tested as a reforming catalyst at various reforming temperatures. The reaction characteristics of woody biomass tar were also investigated by TGA at a variety of heating rates. With all three catalysts conversion efficiency of tar and soot increased at increasing temperature. The reforming of tar and soot in the synthetic gas induce the increase of combustible gases such as $H_2$, CO and $CH_4$ in the product gas. The nickel-based catalyst showed a higher tar and soot conversion efficiency than mineral catalysts under the same temperature conditions.

• 대한안전경영과학회지
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• 제19권4호
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• pp.149-155
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• 2017

This study is analyzed combustion phenomena based on the environmental energy facility incinerator. It is assumed that combustible components of waste are composed of carbon and hydrogen, and the combustion process of fuel is by setting as multi-component / multistage reaction. As the combustion chamber is burned, the high temperature environment is achieved, also the heat transfer accompanied by the turbulent flow and the generation of NOx, a pollutant, are interpreted to predict the thermal and fluid characteristics and pollution emissions of the grate incinerator. As the result of internal flow analysis, the slow flow around the ash chute and the mixing effect due to the complicated turbulence around the combustion chamber were predicted to show excellent performance. It is shown to the internal average temperature was about $1024^{\circ}C$, around the about $1000^{\circ}C$ homogeneous temperature distribution. Due to the sudden temperature decrease in the boiler, the flue gas temperature at the outlet was estimated to be about $220^{\circ}C$.

• 한국수소및신에너지학회논문집
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• 제32권1호
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• pp.68-76
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• 2021

Climate change problems occur during the use of fossil fuel and the process of biogas production. Research continues to convert carbon dioxide and methane, the major causes of climate change, into high-quality energy sources. in order to present the performance potential for the novel plasma-recuperative burner reformer, the reforming characteristics for each variable were indentified. The optimal operating condition of was an O2/C ratio of 1.0 and a total gas supply of 20 L/min. At this time, CH4 conversion was 64%, H2 selectivity was 39%, and H2/CO ratio was 1.13, which were the results applicable to the solid oxide fuel cell fuel stack for RPG, or Residential Power Generator. Recirculation of reformed gas increases the amount of H2 and CO, which are combustible gases, especially the amount of H2. As a result, the H2 selectivity is improved, and high-quality gas can be produced.