• Journal of Energy Engineering
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• v.12 no.4
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• pp.320-327
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• 2003

A CFD (Computational fluid Dynamics) research is conducted for the investigation of the fuel alteration of MBTU (medium-Btu) gas in IGCC gas turbine combustor. The computational analysis method of the gas turbine combustor is constructed by incorporating MBTU gas reaction and fuel NOx models into commercial CFD code. With the use of the present analysis method, comparisons are made on the flow velocity, the chemical species and the temperature distributions, and on the flame shape and behavior of gas turbine combustor firing natural gas and MBTU gases (coal gas, heavy residue oil gas). Furthermore, the NOx formation characteristics and the turbine matching condition of the combustor are analyzed. Based on the computed analysis results, the present study provides the directions for the redesign and the design modification of IGCC gas turbine combustor firing MBTU gas as alternative fuel.

• Journal of Energy Engineering
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• v.13 no.2
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• pp.118-127
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• 2004

The purpose of this study is experimentally to analyze that intake port swirl, injection system and turbocharger have an effect on the engine performance and the emission characteristics in a V8 type turbocharged intercooler D.I. diesel engine of the displacement 16.7ι, and to suggest the improvement of engine performance. Generally to enhance engine power, TCI diesel engine is put to practically use turbo-charged intercoler in order to increase boost efficiency which is cooled boost air. As results of considering the factors of the intake port of swirl ratio 2.25, compression ratio 17.5, re-entrant 8.5$^{\circ}$ combustion bowl, nozzle hole diameter ${\Phi}$0.33*3+${\Phi}$0.35*2, nozzle protrusion 3.18mm, injection timing BTDC 12$^{\circ}$CA and turbo charger (compressor 0.6A/R+46Trim, turbine 1.0A/R+57Trim) is the best in the full range of operating in the engine performance and the exhaust characteristics of NO$\_$x/ concentration. Therefore their factors are appropriated as intake system, injection and turbocharger system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.5
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• pp.2069-2074
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• 2013

The use of the electromagnetic clutch water pump for internal combustion engine vehicles saves fuel and leads to a reduction in emissions. The clutch water pump allows the engine cooling system to select the optimum operation condition by using coolant flow rate on/off control. This study investigated the characteristics of fuel consumption and emissions of the diesel engine cooling system using the clutch water pump. The electromagnetic clutch operation reduced by about 49% of engine warm up period at idle condition and controlled the optimum high coolant temperature at driving condition. Therefore, fuel consumption was enhanced by about 5%, and emissions such as HC, CO and $CO_2$ were also reduced to a certain degree even though NOx increased a little bit, compared to those of the conventional water pump under NEDC mode which represents the real driving pattern.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.9
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• pp.829-836
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• 2013

The combustion characteristics with variations in synthetic natural gas (SNG) compositions were studied in a lab-scale combustor. The objective of the current study is to investigate the flame stabilization, flame structure, and spectrometry in a non-premixed SNG flame with varying fuel compositions. For the analysis of light emission in SNG flames, we used a spectrometer. As experimental conditions, the fuel jet velocity at the nozzle exit $u_F$ was varied from 5 to 40 m/s and the coaxial air velocity $u_A$ was varies from 0 to 0.43 m/s. The experiments showed that the flame stability increased with the hydrogen component in SNG.

• Fire Science and Engineering
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• v.19 no.3 s.59
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• pp.58-63
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• 2005

Experimental measurements of flames and the product properties were performed for small kerosene pool fires. which is widely used as a fire source of laboratory scale experiments with scaling modeling. The flame length and flickering frequency were investigated for the flame structures, and compared with the theory. Three measurement methods were introduced to clarify the smoke characteristics, i.e. various gas concentrations, smoke density and thermophoretic sampling with transmission electron microscopy (TEM). The yield of carbon dioxide and the consumption of oxygen were proportional to the heat release rate of pool fires, but there is no trend on carbon monoxide emission. Smoke density of turbulent flames was exponentially increased with the heat release rate. The morphology of the soot particle was investigated to address the degree of soot maturing. The results show that the similar smoke morphology between an inverse jet flame and a pool fire exists despite of different combustion controlling mechanisms.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.1
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• pp.131-140
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• 2005

To investigate secondary carbonaceous species within PM$_{10}$ and PM$_{2.5}$ in Seoul urban Metropolitan Area (SMA), Korea. atmospheric particulate matters samples were collected at two sites of SMA at UOS (The University Of Seoul station) sites and IHU (InHa University of Incheon station) during the period of 4 to 14 January and 12 to 22 May, 11 to 15 August 2004, and their characteristics were qualitatively discussed. during January and May and August of 2004. Daily average mass concentration 0.095 mg/㎥ in PM$_{10}$ and 0.053 mg/㎥ in PM$_{2.5}$ for mass respectively. were observed in SMA. The concentrations of carbonaceous species contributed 18.4% and 16.4% of PM$_{2.5}$ and PM$_{10}$ during the sampling period, respectively, of which OC accounted for 68% and 52% more of the total carbon (TC). OC and EC concentrations and their mass percentages were higher in PM$_{2.5}$ than in PM$_{10}$ which could be attributed to generation process. Organic aerosols would constitute up to 38% of PM$_{2.5}$ based on the evaluation of 1.6 for the ratio of OC to organic particulate. Secondary organic carbon (SOC) were estimated to be more than 13% and up to 68% of total OC based on the minimum OC/EC ratio of 1.06/1.11 using least square method. Comparisons of OC and EC with trace elements. As results of carbonaceous species analysis, the dominant factor in view of fine particle (PM$_{10}$/PM$_{2.5}$) is primary emission source such as mobile, fossil fuel combustion etc. during winter time in SMA. But in summer periods, remarkable fine particle increasing factor was secondary organic carbon dependent to photochemical reaction. reaction.n. reaction.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.253-259
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• 2012

Disposal of high amount of coal combustion by-products, such as fly ash and bottom ash, is of a great concern to the country, due to the huge treatment cost and land requirement. On the other hand, those coal-ash wastes are considered to have desirable characteristics that may improve physical, chemical, and biological properties of soils. Especially, compared with fly ash, bottom ash has a larger particle size, porous surface area, and usable amount of micronutrients. In the present study, we examined bottom as a soil amendment for mitigating $CO_2$ emission and enhancing carbon sequestration in soils fertilized with organic matter (hairy vetch, green barely, and oil cake fertilizer). Through laboratory incubation, $CO_2$ released from the soil was quantitatively and periodically monitored with an enforced-aeration and high-temperature respirometer. We observed that amendment of bottom ash led to a marked reduction in $CO_2$ emission rate and cumulative amount of $CO_2$ released, which was generally proportional to the amount of bottom ash applied. We also found that the temporal patterns of $CO_2$ emission and C sequestration effects were partially dependent on the relative of proportion labile carbon and C/N ratio of the organic matter. Our results strongly suggest that amendment of bottom ash has potential benefits for fixing labile carbon as more stable soil organic matter, unless the bottom ash contains toxic levels of heavy metals or other contaminants.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.5
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• pp.518-524
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• 2013

In this study, we conducted a study on characteristics of exhaust gas emissions from boiler when water-bunker oil mixed by homogenizer was burned in boiler. The results showed that NOx concentration and CO concentration of the homogenized bunker oil was decreased by 19% and 54% compared to pure bunker oil pretreatment was not being performed. And, in the case of water-bunker A oil, the NOx concentration was decreased with increasing water mixing ratio in bunker A oil. In particular, the NOx concentration in exhaust gas of 20 %water-80 %bunker A oil decrease by 45 % compared with pure bunker-A. However, the CO concentration in exhaust gas of 20 %water-80 %bunker A oil shows irregular changes. This means that the mixing of water more than a certain amount can cause a decrease in combustion performance. From this result, it can be found that critical mixing ratio of water in bunker A oil for normal combustion is 15% in this study. Deposition amount of soot that is collected in the vicinity of the chimney was decreased with increasing water mixing ratio.

• Clean Technology
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• v.24 no.4
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• pp.323-331
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• 2018

The results of an experimental investigation on the co-firing characteristics and slagging behavior of dried and hydrothermal carbonization sewage sludge, sub-bituminous coal, and wood pellet in a fluidized bed were presented. Combustion tests were conducted in a lab-scale bubbling fluidized bed system at the uniform fuel-air equivalence ratio, air flow rate, and initial bed temperature to measure bed temperature distribution and combustion gas composition. 4 different fuel blending cases were prepared by mixing sewage sludge fuels with coal and wood pellet with the ratio of 50 : 50 by the heating value. $NO_x$ was mostly NO than $NO_2$ and measured in the range of 400 to 600 ppm in all cases. $SO_2$ was considered to be affected mostly by the sulfur content of the sewage sludge fuels. The cases of hydrothermal carbonization sewage sludge mixture showed slightly less $SO_2$ emission but higher fuel-N conversion than the dried sewage sludge mixing cases. The result of fly ash composition analysis implied that the sewage sludge fuels would increase the possibility of slagging/fouling considering the contents of alkali species, such as Na, K, P. Between the two different sewage sludge fuels, dried sewage sludge fuel was expected to have the more severe impact on slagging/fouling behavior than hydrothermal carbonization sewage sludge fuel.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.626-631
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• 2019

The policy-making and technological development for the supply expansion of eco-friendly automobiles has been continuing, but the internal combustion engines still accounts for about 95%. Also, in order to meet the stricter emission regulations of internal combustion engines based on fossil fuels, the proportion of after-treatments for vehicles and (ocean going) vessels is gradually increasing. This study is a basic study for the post-Euro-VI exhaust response of CNG buses, and it is to investigate the basic characteristics according to Pd substitution transition metal effect, catalyst volume effect and space velocity. A catalysts was prepared and tested using a model gas reactor. The NGOC catalyst with 3Pd exhibited the highest catalytic activity with 22% at $300^{\circ}C$, 48% at $350^{\circ}C$ and about 75% at $500^{\circ}C$. 3Co NGOC containing 3wt% of transition metal was excellent in oxidation ability, and it was small in size of 2nm, and the degree of catalyst dispersion was improved and de-NO/CO conversion was high. The volume of the NGOC-LNT-SCR catalyst system was optimal in the combination of 1.5+0.5+0.5 with a total score of 165, considering $de-CH_4/NOx$ performance and catalyst cost. For SV $14,000h^{-1}$, the $CH_4$ reduction performance was the highest at about 20%, while the SV $56,000h^{-1}$ was the lowest at about 5%. If the space velocity is small, the flow velocity decreases and the time remaining in the catalyst volume become long, so that the harmful gas was reduced.