• Title/Summary/Keyword: Carbon particle

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Recycling of Carbon Particle from Phenol Resin Waste using Supercritical Fluid (초임계 유체를 이용한 폐페놀수지로부터 카본입자 재활용 연구)

  • Cho, Hang-Kyu;Lim, Jong Sung
    • Korean Chemical Engineering Research
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    • v.55 no.2
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    • pp.220-224
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    • 2017
  • In this study, we investigated a new recycling method of phenol resin, which is widely used to make electric insulation boards and adhesives, into carbon particles by using supercritical fluids. Because phenol resin is insoluble and infusible, most of the phenol resin wastes are buried in the ground or incinerated, which leads to environmental pollution. Therefore, development of a new method to recycle phenol resin waste is an urgent issue. In this study, phenol resin waste was treated with four sub/supercritical solvents: ethanol, acetone, water, and methanol. For all the sub/supercritical solvents, the phenol resin wastes were broken down into carbon nano particles at much lower temperatures than that required in the existing carbon particle manufacturing processes. We investigated the difference of morphologies and physical properties of recycled carbon particles according to the use of various solvents. As a result, carbon nano particles with the same amorphous structure were obtained from phenol resin waste with the usage of various sub/supercritical solvents at much lower temperature.

Particle Attrition Characteristics in a Bubbling Fluidized Bed Under High Temperature and High Pressure Conditions (고온 고압 조건하의 기포유동층 반응기에서의 입자 마모특성)

  • Moon, Jong-Ho;Lee, Dong-Ho;Ryu, Ho-Jung;Park, Young Cheol;Lee, Jong-Seop;Min, Byoung-Moo;Jin, Gyoung Tae
    • Clean Technology
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    • v.20 no.4
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    • pp.359-366
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    • 2014
  • Attrition characteristics of PKM1-SU particles, $CO_2$ absorbents for pre-combustion $CO_2$ capture process, and FCC particles, catalytic particles for hydro cracking of crude oil, were investigated at high temperature and high pressure conditions. Particle attrition tests were executed at various kinds of temperature ($0-400^{\circ}C$) and pressure (0-20 bar) conditions in a cylinder type bubbling fluidized bed with 15.1 cm diameter, 120 cm height and 1 mm orifice-sparger tube. Attrited particles before and after tests were analyzed by BET, optical microscopy, and particle size analyzer. Effects of bed material height (solid inventory) and steam injection were also verified by using ASTM D5757-95, conventional attrition test method.

Particle Scavenging Properties of Rain Clarified by a Complementary Study with Bulk and Semi-bulk Samples

  • Ma, Chang-Jin;Kang, Gong-Unn
    • Journal of Korean Society for Atmospheric Environment
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    • v.34 no.1
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    • pp.177-186
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    • 2018
  • It is a well-known fact that precipitation plays an important role in capturing ambient particles, however, the details of particle scavenging properties have not been fully proved. To clarify the particle scavenging properties, a complementary study was carried out with the bulk and semi-bulk rain samples collected in an urban city of Japan. pH showed a continued downturn for a little bit at the beginning rainfall and then a turn-up in the following rainfall. The recorded pH values of rainwater (ranged from 3.5-4.6) demonstrated that the strong acid rain was observed during our field measurements. Compared to the subsequent rainfall, electrical conductivity in the beginning rainfall had about 1.3 times higher level. Sulfur showed an overwhelmingly high concentration compared to other elements in both ambient total suspended particles (TSP) and rain samples. On the contrary to ambient TSP, every element including Ca and Zn in rain showed a continued rise in concentration accompanied by increasing of rainfall amount. During the first period of the rainfall there was no meaningful change in elemental carbon concentration, however, it was largely increased (up to $0.2mg\;L^{-1}$) in the sequential rainfall (4.0-4.5 mm rainfall amount). The theoretically calculated number concentration of particles scavenged by raindrops showed a strong decrease of with the increasing droplet diameter regardless of particle type.

Literature Review of Clinical Usefulness of Heavy Ion Particle as an New Advanced Cancer Therapy (첨단 암 치료로서 중입자치료의 임상적 유용성에 대한 고찰)

  • Choi, Sang Gyu
    • Journal of radiological science and technology
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    • v.42 no.6
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    • pp.413-422
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    • 2019
  • Heavy ion particle, represented carbon ion, radiotherapy is currently most advanced radiation therapy technique. Conventional radiation therapy has made remarkable changes over a relatively short period of time and leading various developments such as intensity modulated radiation therapy, 4D radiation therapy, image guided radiation therapy, and high precisional therapy. However, the biological and physical superiority of particle radiation, represented by Bragg peak, can give the maximum dose to tumor and minimal dose to surrounding normal tissues in the treatment of cancers in various areas surrounded by radiation-sensitive normal tissues. However, despite these advantages, there are some limitations and factors to consider. First, there is not enough evidence, such as large-scale randomized, prospective phase III trials, for the clinical application. Secondly, additional studies are needed to establish a very limited number of treatment facilities, uncertainty about the demand for heavy particle treatment, parallel with convetional radiotherapy or indications. In addition, Bragg peak of the heavy particles can greatly reduce the dose to the normal tissues front and behind the tumor compared to the photon or protons. High precision and accuracy are needed for treatment planning and treatment, especially for lungs or livers with large respiratory movements. Currently, the introduction of the heavy particle therapy device is in progress, and therefore, it is expected that more research will be active.

Effect of Carbon Fiber Layer on Electrochemical Properties of Activated Carbon Electrode

  • Jong kyu Back;Jihyeon Ryu;Yong-Ho Park;Ick-Jun Kim;Sunhye Yang
    • Journal of Electrochemical Science and Technology
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    • v.14 no.2
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    • pp.184-193
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    • 2023
  • This study investigates the effects of a carbon fiber layer formed on the surface of an etched aluminum current collector on the electrochemical properties of the activated carbon electrodes for an electric double layer capacitor. A particle size analyzer, field-emission SEM, and nitrogen adsorption/desorption isotherm analyzer are employed to analyze the structure of the carbon fiber layer. The electric and electrochemical properties of the activated carbon electrodes using a carbon fiber layer are evaluated using an electrode resistance meter and a charge-discharge tester, respectively. To uniformly coat the surface with carbon fiber, we applied a planetary mill process, adjusted the particle size, and prepared the carbon paste by dispersing in a binder. Subsequently, the carbon paste was coated on the surface of the etched aluminum current collector to form the carbon under layer, after which an activated carbon slurry was coated to form the electrodes. Based on the results, the interface resistance of the EDLC cell made of the current collector with the carbon fiber layer was reduced compared to the cell using the pristine current collector. The interfacial resistance decreased from 0.0143 Ω·cm2 to a maximum of 0.0077 Ω·cm2. And degradation reactions of the activated carbon electrodes are suppressed in the 3.3 V floating test. We infer that it is because the improved electric network of the carbon fiber layer coated on the current collector surface enhanced the electron collection and interfacial diffusion while protecting the surface of the cathode etched aluminum; thereby suppressing the formation of Al-F compounds.

Effect of Carbon-coated Silicon/Graphite Composite Anode on the Electrochemical Properties

  • Kim, Hyung-Sun;Chung, Kyung-Yoon;Cho, Byung-Won
    • Bulletin of the Korean Chemical Society
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    • v.29 no.10
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    • pp.1965-1968
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    • 2008
  • The effects of carbon-coated silicon/graphite (Si/Gr.) composite anode on the electrochemical properties were investigated. The nanosized silicon particle shows a good cycling performance with a reasonable value of the first reversible capacity as compared with microsized silicon particle. The carbon-coated silicon/graphite composite powders have been prepared by pyrolysis method under argon/10 wt% propylene gas flow at $700{^{\circ}C}$ for 7 h. Transmission electron microscopy (TEM) analysis indicates that the carbon layer thickness of 5 nm was coated uniformly onto the surface silicon powder. It is confirmed that the insertion of lithium ions change the crystalline silicon phase into the amorphous phase by X-ray diffraction (XRD) analysis. The carbon-coated composite silicon/graphite anode shows excellent cycling performance with a reversible value of 700 mAh/g. The superior electrochemical characteristics are attributed to the enhanced electronic conductivity and low volume change of silicon powder during cycling by carbon coating.

Synthesis of Carbon Nanotube and Optical Application (탄소나노튜브의 제조 및 광학적 응용 연구)

  • Joo, Young-Joon;So, Won-Wook;Kim, Heejoo;Chol, Ho-Suk;Moon, Sang-Jin
    • Transactions of the Korean hydrogen and new energy society
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    • v.14 no.3
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    • pp.247-257
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    • 2003
  • To investigate the effect of preparing condition on the physical properties of carbon nanotubes suitable for optical applications, carbon nanotubes were synthesized by thermal chemical vapor deposition using Ni particles as a catalyst on stainless steel substrate and acetylene as a reactant gas. To examine the physical and optical properties, SEM, TEM, Ram an, UV-visible, and photoluminescence spectroscopy were used. The physical properties of carbon nanotubes such as diameter, degree of growth density and morphology were closely related to such experimental conditions as Ni particle size, growing pressure, and etching condit on of Ni particles, it appeared from the light absorbance and photoluminescence spectra of carbon nanotube mixture prepared with an addition of a photopolymer, P3HT(Poly(3-hexylthIop hene)) that carbon nanotube could do a role as a kind of electron acceptor for solar cell application.

Evaluation of Coated Layers of HTGR Nuclear Fuel Particle

  • Song, M.S.;Choi, Y.;Kim, B.G.;Lee, Y.W.;Lee, J.K.
    • Proceedings of the Korean Nuclear Society Conference
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    • 2004.10a
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    • pp.1047-1048
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    • 2004
  • Simulation Coated layers of a nuclear fuel particle were evaluated by field emission scanning electron microscopy and nano-indentation method to give basic data to estimate 'Amoeba effect' and give an optimum fabrication condition and high quality control. Coated layers on the fuel kernel are in the order of buffer pyrolytic carbon, inner pyrolytic carbon, silicon carbide and outer pyrolytic carbon layers, which average thicknesses are 95, 25, 30 and 28 ${\mu}m$, respectively. Their densities and hardnesses are 1.08, 1.15, 3.18, 1.82 $g/cm^3$ and 0.522, 0.874, 9.641, and 2.726 GPa, respectively. Comparing theoretical density of pyrolytic carbon of 2.22 $g/cm^3$, the relative amount of porosity in each layer is about 52% for buffer, 48% for inner PyC and 18% for outer PyC.

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Fabrication of tungsten carbide by pulsed electric current heating (펄스통전가열에 의한 텅스텐 탄화물의 제조)

  • Hong, Seong-Hyeon;Kim, Hyun-Jin
    • Particle and aerosol research
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    • v.5 no.4
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    • pp.153-158
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    • 2009
  • Tungsten carbide powder was fabricated with carbothermal reaction by pulsed electric current flowing in compact of tunsten oxide and carbon. The mixed powder of tunsten oxide and carbon was ball-milled into ultrafine powders. The mixed powder of tungsten oxide and carbon was put into carbon mold and heat-treated at $1050{\sim}1200^{\circ}C$ by pulsed electric current flowing. The formation of tungsten carbide powder could be achieved by heat treatment at $1200^{\circ}C$ for 10 minitues.

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