• Title/Summary/Keyword: Fuel Particles

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Effect of Fuel on Synthesis of Nanocrystalline Ni particles by a Combustion Synthesis Process (연소합성법을 이용한 Ni 분말 합성에서 첨가 연료의 영향)

  • 정충환;신형철;이희균;홍계원;윤순길
    • Journal of Powder Materials
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    • v.8 no.1
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    • pp.13-19
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    • 2001
  • Ni and NiO particles were made by a combustion synthesis process. The characteristics of synthesized powders were investigated with various kinds and amounts of fuels such as urea, citric acid and glycine. Ni phase particles without NiO phase were obtained through combustion synthesis process in air atmosphere with-out further calcinations process, when the content of glycine was 2.44 times of the stoichiometric ratio in the precursor solution. Primary particle sizes of synthesized Ni and NiO particles were about 20∼30 nm.

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Production of Fine Metal Oxide Particles in Supercritical Water (초임계수를 이용한 금속산화물 미세입자 제조)

  • Lee, Joo-Heon;Park, Young-Woo
    • Applied Chemistry for Engineering
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    • v.10 no.1
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    • pp.173-176
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    • 1999
  • The production of fine metal oxide particles in supercritical water has been studied. Cobalt nitrate solution and manganese nitrate solution have been selected as model solutions for metal salt aqueous solution and the particles of cobalt oxide and manganese oxide have been produced. It was observed that the production of fine metal oxide particles in supercritical water was feasible and the dehydration rate was remarkably high in supercritical water. In spite of a short residence time (3~100 seconds), fine particles ($0.5{\sim}2{\mu}m$) have been produced. In the supercritical water process, the temperature of mixer had a significant effect on particle size and size distribution. It was observed that a change in reaction temperature resulted in the control of particle size.

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Effect of Ethanol Content on Fine Soot Particle Emission from a Diesel-Ethanol Blended Fuel Diesel Engine (디젤-에탄올 혼합연료의 에탄올 함량이 미세 그을음(Soot) 입자 배출특성에 미치는 영향)

  • Park, Su-Han;Cha, June-Pyo;Kwon, Seok-Ju;Park, Sung-Wook;Lee, Chang-Sik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.12
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    • pp.1359-1365
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    • 2011
  • The purpose of this study is to investigate the effect of ethanol content on the emission of nanosized particles from a diesel-ethanol blended fuel engine. The engine combustion and exhaust emission characteristics of a singlecylinder diesel engine were analyzed using an emission analyzer and an SMPS(scanning mobility particle sizer). The analysis revealed that soot emission increased with the ignition delay. When the ignition delay was fixed, an increase in the ethanol content caused a decrease in the soot emission. With an increase in the ethanol blending ratio, the number concentration and mass distribution of nanosized particles generally decreased. However, for 30% ethanol blending, large particles were observed because of the agglomeration of soot particles, and consequently, the particle mass increased.

Characterization of Spherical NiO-YSZ Anode Composites for Solid Oxide Fuel Cells Synthesized by Ultrasonic Spray Pyrolysis

  • Lim, Chae-Hyun;Lee, Ki-Tae
    • Journal of the Korean Ceramic Society
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    • v.51 no.4
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    • pp.243-247
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    • 2014
  • Spherical NiO-YSZ particles were synthesized by ultrasonic spray pyrolysis (USP). The morphology of the synthesized particles can be modified by controlling parameters such as precursor pH, carrier-gas flow-rate, and temperature of the heating zone. The synthesized spherical NiO-YSZ particles have rough surface morphology at high carrier-gas flow-rates due to rapid gas exhaustion and insufficient particle ordering. The Ni-YSZ cermet anode synthesized by ultrasonic spray pyrolysis at a flow rate of l L/min, with precursor solution at pH4, showed a higher maximum power density of 256 $mW/cm^2$ compared to a conventionally mixed Ni-YSZ anode (185 $mW/cm^2$) at $800^{\circ}C$. While the area-specific resistance of conventionally mixed Ni-YSZ anodes increases gradually with operation time (indicating performance degradation), the Ni-YSZ anode synthesized by USP does not exhibit any performance degradation, even after 500 h.

Preparation and Characterization of Uranium Silicide Dispersion Nuclear Fuel by Centrifugal Atomization (원심분무에 의한 Uranlum filicide 분산핵연료의 제조와 특성)

  • 김창규
    • Journal of Powder Materials
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    • v.1 no.1
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    • pp.72-78
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    • 1994
  • Two kinds of $U_3Si$ powders and $U_3Si$ dispersed nuclear fuel meats have been prepared by conventional comminution process and a newly developed rotating disk atomization process. In contrast to angular shape and broad size distribution of the conventionally processed powder, the atomized powder was spherical and showed narrow size distribution. For the atomized powder, the heat treatment time for the formation of $U_3Si$ by a peritectoid reaction was reduced to about one tenth, thanks to microstructure refinement by rapid cooling of about 5$\times$104 K/s. The extruding pressure of atomized $U_3Si$ powder and Al powder mixture was lower than that of comminuted $U_3Si$ and Al powder mixture. The elongation of the atomization processed fuel meats was much higher than that of the comminution processed fuel meats and remained over 10% up to 80wt.% of $U_3Si$ powder fraction in the fuel meats. It appears therefore that the loading density of $U_3Si$ in fuel meat can be increased by using atomized $U_3Si$ powder. The atomized spherical particles were randomly distributed, while the comminuted particles with angular and longish shape were considerably aligned along the extrusion direction. Along the transverse direction of the extraction the electrical conductivity of the atomization processed fuel meats was appreciably higher than that of comminution processed fuel meats. This tendency became pronounced as $U_3Si$ content increased. Because the thermal conduction which is believed to be proportioned to the electrical conduction in the nuclear fuel meats occurs in radial direction, the atomization processed fuel can be better used in research reactors where high thermal conductivity is required.

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Preparation of Energetic Metal Particles and Their Stabilization (에너제틱 금속입자 제조 및 안정화 기술)

  • Lee, Hye Moon;Kim, Kyung Tae;Yang, Sangsun;Yu, Ji-Hun;Kim, Yong-Jin
    • Particle and aerosol research
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    • v.9 no.3
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    • pp.173-185
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    • 2013
  • Oxidations of metal generate large quantity of thermal and light energies but no toxic pollutants, so that metals with high calorific values, such as beryllium, boron, aluminum, magnesium, and lithium, are possible to be used as clean fuels instead of fossil fuels. However, they are so explosive due to very high oxidation rates that they should be stabilized by their surface passivation with oxides, organics and inorganics. For reasonable use of energetic metal particles as solid fuel, therefore, some detail information, such as thermal properties, preparation and passivation methods, and application area, of the energetic metals is introduced in this manuscript.

Characterization of Soot Particles Generated in Non-sooting and Sooting Normal Diffusion Flames (Sooting 및 Non-Sooting 정상 확산 화염에서 생성되는 매연 입자의 특성에 대한 연구)

  • Choi, In-Chul;Lee, Jae-Bok;Hwang, Jung-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.7
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    • pp.984-993
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    • 2000
  • Characteristics of carbon soot particles generated in diffusion flames were studied. Non-sooting and sooting normal diffusion flames using propane or ethylene as fuel were selected. In the flames, soot volume fraction was measured by a thermocouple, and primary particle diameter and cluster size were analyzed by TEM photographs. The characteristics of soot particles depended on flame(non-sooting or sooting) and fuel(propane or ethylene) type. Unlike the sooting diffusion flames, particle growth and oxidation processes were clearly observed in the non-sooting diffusion flames. In the sooting diffusion flames, soot particle size was slightly changed at the flame tip.

Development of Coke Breeze Combustion Technology in the Calcining Rotary Kiln (Rotary Kiln 식석회소성로에서의 분코크스 연소 기술)

  • Kim, J.G.;Cho, H.C.;Kim, Y.W.
    • 한국연소학회:학술대회논문집
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    • 2004.11a
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    • pp.41-45
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    • 2004
  • A dust injection system was developed for the lime calcining rotary kiln for the coke dust from the coke dry quenching(CDQ) facility to be used as a fuel. The CDQ dust was injected with the gaseous fuel through the hole in the burner. In order to prevent the spot heating large particles should be removed from dust and dust should be injected as fast as possible so that particle combustion lasts as long as possible without precipitation. This is especially necessary when dust is burned together with gaseous fuel because the gaseous fuel can not go so far and in addition dust combustion aggravates hot spot heating. In this research a rotation drum screen was used to remove particles with diameter larger than 4mm and dust injection speed was 40m/sec. And the burner was adjusted not to use swirl that hinders flame go far away. With these measures scale generation iside the kiln could be reduced to be negligible and in addition NOx emission could be reduced from 150ppm to 20ppm. The fuel reduction was about 85Mcal/T-lime.

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THE EFFECT OF SI-RICH LAYER COATING ON U-MO VS. AL INTERDIFFUSION

  • Ryu, Ho-Jin;Park, Jae-Soon;Park, Jong-Man;Kim, Chang-Kyu
    • Nuclear Engineering and Technology
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    • v.43 no.2
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    • pp.159-166
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    • 2011
  • Si-rich-layer-coated U-7 wt%Mo plates were prepared in order to evaluate the diffusion barrier performance of the Si-rich layer in U-Mo vs. Al interdiffusion. Pure Si powder was used for coating the U-Mo plates by annealing at $900^{\circ}C$ for 1 h under vacuum of approximately 1 Pa. Si-rich layers containing more than 60 at% of Si were formed on U-7 wt%Mo plates. Diffusion couple tests were conducted in a muffle furnace at $560-600^{\circ}C$ under vacuum using Si-rich-layer-coated U-Mo plates and pure Al plates. Diffusion couple tests using uncoated U-Mo plates and Al-(0, 2 or 5 wt%)Si plates were also conducted for comparison. Si-rich-layer coatings were more effective in suppressing the interaction during diffusion couple tests between coated U-Mo plate and Al, when compared with U-Mo vs. Al-Si diffusion couples, since only small amounts of Al in the coating could be found after the diffusion couple tests. Si-rich-layer-coated U-7wt%Mo particles were also prepared using the same technique for U-7 wt%Mo plates to observe the microsturctures of the coated particles.

Analysis of Effect of Fuel Additive on Soot Suppression Using Laser Scattering Technique (광 산란 기술을 이용한 연료 첨가제의 그을음 억제 효과 분석)

  • Seo, Hyoungseock;Kim, Kibum
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.7
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    • pp.204-210
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    • 2016
  • This paper presents an experimental analysis of the growth and oxidation processes of soot particles generated in an isooctane diffusive laminar flame due to incomplete combustion. The effects of iron-based diagnostics were employed to measure the elastic scattering light from soot particles in a flame at different flame heights, and the differential scattering coefficients were calculated through a calibration process. The growth and oxidation of soot particles in flame was investigated by comparing differential scattering coefficients, and the soot volume fraction was seen to decrease in the soot oxidation process. In the same manner, the differential scattering coefficients were calculated for iron-based fuel-additive seeded flame, and these coefficients were revealed to be smaller than those obtained in the fuel-additive unseeded flame. In addition, transmission through the radial direction of the flame was measured, and transmission in the soot oxidation regime was approximately 5% higher for the seeded flame. The propensity of the data coincided well with the differential scattering coefficients, and it can be concluded that the iron component of the fuel additive plays a crucial role as a catalyst, which eventually enhanced soot particle oxidation.