• Journal of the Korean Society of Combustion
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• v.20 no.4
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• pp.26-33
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• 2015

American NREL (National Renewable Energy Laboratory) reported that BD20 could reduce PM, CO, SOx and cancerogenic matters by 13.6%, 9.3%, 17.6% and 13% respectively, compared to diesel fuel. BD20 has been being tested on garbage trucks and official vehicles at Seoul City, which is positive on air environment, but negative on combustion by higher viscosity in winter season. This study investigated the combustion characteristics by employing multi cavity piston for improving the deterioration of combustibility caused by the higher viscosity of the biodiesel fuel such as BD20 with the combustion flames taken by a high speed camera and the cylinder pressure diagram. A 4-cycle single cylinder diesel engine was remodeled to a visible 2-cycle engine for taking the flame photographs, which has a common-rail injection system. The test was done at laboratory temperature of about $4{\sim}5^{\circ}C$.

• Journal of the Korea Safety Management & Science
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• v.11 no.3
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• pp.49-56
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• 2009

The quantity of the fuel gas consumed is trending upwards because it can be easily delivered but isn't deteriorated and doesn't have any environmental pollution. Though there are many advantages to use the fuel gas, it can be hesitated to consume more gas because of its explosiveness and combustibility. So paying more attentions to prevent the fuel gas accidents is required. In this paper, we examine the present situation data about the fuel gas accidents and analyze them statistically using ANOVA. we confirm that there is an acceptable difference between the mean values of accidents classified by the kind of gas, the cause, the type and the place but isn't by month. It is expected that our result can be applied as preliminary data when mapping out a strategy for preventing the fuel gas accidents.

• Journal of the Korean Society of Tobacco Science
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• v.16 no.1
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• pp.43-52
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• 1994

To investigate the factors of the improvement of cultivation methods according to the plant type, three Burley tobacco cultivars were done. Experiments on the variability of plant type and factors representing the productivity and quality of the cultivar were subsequently carried out in relation to different fertilizer levels. Results are summarized as below. Use of more fertilizer resulted in higher plant height and longer leaf length but smaller mean leaf inclination(MLI). The horizontal leaf area distribution became greater in parts distal to the stem and the vertical leaf area distribution became greater in lower half than in upper half as the amount of fertilizer applied was increased. Br. 49 was the largest but Br. 21 and NTN 77 were similar with respect to both CGR and NAR. The yield was greater in larger MLI cultivars. These three characteristics became greater when the tobacco were heavier in the cultivars of larger MLI and increased with higher amount of fertilizer. Harvest index became greater as the amount of fertilizer decreased but not significantly differ among the cultivars. Total nitrogen content and nitrate - form nitrogen content were greater, more amount of fertilizer, and larger MLI cultivar plots. Total nitrogen content was higher in upper leaves. The filling power of tobacco leaves decreased but combustibility of leaves showed not significant trend as fertilizer application level increased.

• Journal of the Korean Society of Tobacco Science
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• v.16 no.1
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• pp.34-42
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• 1994

Experiments on the variability of plant type and factors representing the productivity and quality of the cultivars were subsequently carried out in relation to different plant density. Results are summarized as below. The higher was the plant density, the greater was the plant height and mean leaf inclination(MLI). As the plant density increased, the horizontal leaf area distribution became greater in proximal to the stem in NTN 77 and Br.49 but evenly in distal part in Br.21. Meanwhile, in terms of vertical leaf area distribution, it was decreased much more in middle and lower leaves than in upper in NTN 77 and Br.49 although it steadily decreased in any part of the plant in Br.21. Br.49 was the largest but Br.21 and NTN 77 were similar with respect to both CGR and NAR. The yield was greater in larger MLI cultivars(NTN 77>Br.49>Br.21). These three characteristics became greater when the tobacco were planted more densely in the field. Dry leaf weight and dry matter weight per plant were heavier in the larger MLI and increased with lower plant density. Total nitrogen content was greater in lower plant density and larger MLI cultivar. The plant density increases filling power seems to be enhanced regardless to the plant type. There was no discernible tendency on combustibility according to the plant density or plant type.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.10a
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• pp.279-282
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• 2010

스티로폼샌드위치패널은 건식공법의 시공편리성, 경제적인 공사비용, 뛰어난 단열성능으로 공장이나 창고건축물을 중심으로 많이 사용되고 있다. 그러나 스티로폼의 여러 가지 장점에도 불구하고 화재에 취약한 단점이 있어 최근 난연성능이 보완된 난연스티로폼패널의 사용이 증가하고 있다. 최근 건축현장에서, 가짜 난연스티로폼패널 사용이 문제되고 있으나 난연성능의 현장 확인에 어려움이 있고 콘칼로리미터 등의 난연성능평가에 시간과 비용이 소요된다. 본 연구에서는 콘칼로리미터를 통해 난연성능이 확보된 난연 스티로폼패널의 심재와 일반스티로폼패널 심재를 대상으로 근-적외선 분광분석을 수행하여 난연성능의 유무에 따라 상이하게 나타나는 고유스펙트럼 흡수를 측정하였다. 각 제품마다 측정된 고유스펙트럼은 통계처리를 통하여 난연스티로폼의 진위여부를 현장에서 구별할 수 있음을 확인하였으며, 비용효율이 높은 현장평가방법으로의 적용이 가능함을 실험을 통해 입증하였다.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.2
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• pp.178-187
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• 2019

Due to the increasing demand of high rank coal, the use of low rank coal, which has economically advantage, is rising in various industries using carbonaceous solid fuels. In addition, the severe disaster of global warming caused by greenhouse gas emissions is becoming more serious. The Republic of Korea set a goal to reduce greenhouse gas emissions by supporting the use of biomass from the Paris International Climate Change Conference and the 8th Basic Plan for Electricity Supply and Demand. In line with these worldwide trends, this paper focuses on investigating the combustibility of high rank coal Carboone, low rank coal Adaro from Indonesia, Baganuur from Mongolia and, In biomass, wood pellet and herbaceous type Kenaf were simulated as kinetic reactivity model. The accuracy of the pore development model were compared with experimental result and analyzed using carbon conversion and tau with grain model, random pore model, and flexibility-enhanced random pore model. In row lank coal and biomass, FERPM is well-matched kinetic model than GM and RPM to using numerical simulations.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.5
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• pp.436-447
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• 2019

The circulating fluidized bed boiler has an advantage that can burn a variety of fuels from low-grade fuel to coal. In this study, for the design of a circulating fluidized bed boiler using wood pellets, a circulating fluidized bed combustion test device using no external heater was manufactured and used. According to the increase of co-combustion rate with wood pellet, combustion fraction and heat flux by combustor height were measured and pollutant emission characteristics were analyzed. In terms of combustibility, the effect on primary and secondary air ratio were also studied. In addition, as a result of analysis of the effect of corrosive nanoparticles on the combustion of coal with wood pellets, it was confirmed that coal is mostly composed of Ca and S, whereas wood pellets are mostly composed of K, Cl, and Na.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.5
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• pp.598-606
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• 2022

With the advancement of industry, the use of various sustainable energy sources and solutions to problems affecting the environment are being actively requested. From this point of view, it is intended to directly burn unused biogas to use it as energy and to solve environmental problems such as greenhouse gases. In this study, a new type of cavity matrix combustor capable of low-emission complete combustion without complex facilities such as separation or purification of biogas produced in small and medium-sized facilities was proposed, and CFD numerical calculation was performed to understand the performance characteristics of this combustor. The cavity matrix combustor consists of a burner with a rectangular porous microwave receptor at the center inside a 3D cavity that maintains a rectangular parallelepiped shape composed of a porous plate that can store heat in the combustor chamber. As a result of numerical calculation, the biogas supplied to the inlet of the combustor is converted to CO and H₂, which are intermediate products, on the surface of the 3D matrix porous burner. And then the optimal combustion process was achieved through complete combustion into CO₂ and H₂O due to increased combustibility by receiving heat energy from the microwave heating receptor.

• Journal of the Korean Society of Combustion
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• v.21 no.4
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• pp.30-38
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• 2016

Flame structure of co-firing coal and palm kernel shell (PKS) was investigated in a pulverized coal swirl burner by particle image velocimetry (PIV). The pulverized coal swirl flame is operated with a PKS blending ratio of 10%, 20%, and 30%. For all operating conditions, flame structures such as internal recirculation zone (IRZ), outer recirculation zone (ORZ), and exhaust tube vortex (ETV) were observed. In the center of flame, the strong velocity gradient is occurred at the stagnation point where the volatile gas combustion actively takes place and the acceleration is increased with higher PKS blending ratio. OH radical shows the burned gas region at the stagnation point and shear layer between IRZ and ORZ. In addition, OH radical intensity increases for a co-firing condition because of high volatile matter from PKS. Because the volatile gas combustion takes place at lower temperature, co-firing condition (more than 20%) leads to oxygen deficiency and reduces the combustibility of coal particle near the burner. Therefore, increasing PKS blending ratio leads to higher OH radical intensity and lower temperature.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.4
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• pp.405-413
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• 2013

The char oxidation characteristics of high ash coal were experimentally investigated at several temperatures (from 900 to $1300^{\circ}C$) for 4 types of coals (Gunvor, Glencore, Noble, and ECM) under atmospheric pressure in a drop tube furnace (DTF). The char reaction rate was calculated from the exhaust gas concentrations (CO and $CO_2$) using FT-IR, and the particle temperature was measured using the two-color method. In addition, the activation energy and pre-exponential factor for high ash coal char were calculated based on the Arrhenius equation. The results show that as the ash content increases, the particle temperature and area reactivity decreases. This is because in high ash coal, the large heat capacity of the ash, ash vaporization, and relatively low fixed carbon content of ash suppress combustibility during char oxidation. As a result, the higher ash content of coal leads to high activation energy.