• Journal of Environmental Science International
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• v.9 no.4
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• pp.345-349
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• 2000

Activated carbons were prepared from Korean coal by steam activation in this study. The variation of pore structure of the activated carbons were investigated according to different carbonization temperatures. Yield, surface area, pore volume and pore structure of this activated carbon were compared with those of activated carbon prepared without carbonization. The investigated carbonization temperature ranged from 700${\circ}C$ to 1,000${\circ}C$. Carbonization was carried out in nitrogen atmosphere for 70 minutes and activation was performed by steam at 950${\circ}C$ for 210 minutes. Surface area and pore volume of the resulting activated carbons increased with carbonization temperature. Also pore volume increased by 20% compared to the activated carbon without carbonization. Especially, in mesopore region, the activated carbon carbonized at 900${\circ}C$ had more pores by 60% than that of activated carbon carbonized at other temperature.

• Carbon letters
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• v.15 no.2
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• pp.146-150
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• 2014

In this work, activated carbon nanofiber (ACNF) electrodes with high double-layer capacitance and good rate capability were prepared from polyacrylonitrile nanofibers by optimizing the carbonization temperature prior to $H_2O$ activation. The morphology of the ACNFs was observed by scanning electron microscopy. The elemental composition was determined by analysis of X-ray photoelectron spectroscopy. $N_2$-adsorption-isotherm characteristics at 77 K were confirmed by Brunauer-Emmett-Teller and Dubinin-Radushkevich equations. ACNFs processed at different carbonization temperatures were applied as electrodes for electrical double-layer capacitors. The experimental results showed that the surface morphology of the CNFs was not significantly changed after the carbonization process, although their diameters gradually decreased with increasing carbonization temperature. It was found that the carbon content in the CNFs could easily be tailored by controlling the carbonization temperature. The specific capacitance of the prepared ACNFs was enhanced by increasing the carbonization temperature.

• Korean Chemical Engineering Research
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• v.43 no.6
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• pp.683-690
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• 2005

The microwave carbonization of rice chaff was performed, and their kinetics were compared to those of conventional thermal carbonization. Thermal carbonization was carried out at $300-600^{\circ}C$ for 30 minutes. The weight loss and C/H mole ratio remarkably increased as increase of temperature, while there was no carbonization by microwave dielectric heating in spite of increasing incident power and irradiation time. However, microwave carbonization was successfully performed by addition of 6 wt％ of thermal carbonized rice chaff, it's C/H mole ratio is larger than 3.0, as a catalytic initiator to uncarbonized rice chaff, and the kinetics was depended on the incident power and irradiation time, resulting in the coincide with thermal carbonization to the Arrhenius equation. The activation energy of microwave carbonization was quite low as compared to that of thermal carbonization, while the kinetic constant was large. This is due to the internal volumetric heating characteristics of carbonized rice chaff by microwave. The effect of ash, and C/H mole ratio and amount of carbonized rice chaff were investigated on microwave carbonization.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.2
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• pp.53-61
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• 2023

Most of the sewage sludge is organic waste containing a large amount of organic substances decomposable by microorganisms by biological treatment. As for existing sewage sludge treatment methods, reduction and fuel conversion are being carried out using technologies such as drying, incineration, torrefaction, carbonization. However, the disadvantage of high energy consumption has been pointed out as latent heat of 539 kcal/kg is consumed based on drying. Therefore, in this study, we intend to produce solid fuel through hydrothermal carbonization(HTC), which is a thermochemical treatment. To evaluate the value of solid fuel, the characteristics of carbonization and fuel ratio were analyzed. As a result, as the hydrothermal carbonization reaction temperature increased, the lower heating value also increased by about 500 kcal/kg due to the increase in the degree of carbonization. H/C, O/C, ratio showed a decreasing trend from 1.78, 0.46 to 1.57, 0.32. When the ratio of ash to combustible content (fixed carbon + volatile) of dry sludge was 0.25 or more, it was derived that the degree of carbonization and calorific value did not increase even when hydrothermal carbonization was performed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.11
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• pp.837-842
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• 2010

This paper describes the crystallinity, growth rate, and surface morphology of single crystalline 3C-SiC (cubic silicon carbide) thin films grown with several carbonization conditions such as temperature, $C_3H_8$ flow rate, time. In case of carbonization, an increase in the carbonization temperature caused a increase in the size and numbers of unsealed void (big black spot) which decrease the crystallinity. In addition, optimal $C_3H_8$ flow rate made carbonization layer form well and prevented the formation of voids. Also, after a period of time, the growth of carbonization layer did not increase no more. The single crystalline 3C-SiC thin films on optimal carbonized Si substrate showed an improvement on the crystallinity, the growth rate, the roughness, and the carrier concentration.

• Carbon letters
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• v.1 no.3_4
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• pp.158-164
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• 2001

It is well known that the fabrication process of carbon/carbon composites is very complex. Above all, the carbonization process have major effect on the morphology development of carbon matrix. Carbon/carbon composites of 4-directional fiber preform were fabricated using the coal tar based pitch as a matrix precursor in this study. According to carbonization pressure of 1 bar, 100 bar, 600 bar, and 900 bar, morphological changes of cokes and matrix of composites were discussed. As the carbonization pressure increased to 600 bar, the flow pattern morphology of bulk mesophse was well developed. On the contrary, mosaic pattern morphology was found in case of 900 bar of carbonization pressure. It is confirmed that the carbonization pressure have profound effect on the degree of graphitization and crystal size of carbon matrix. Even in the highly densified carbon/carbon composites, large voids were still found in the matrix pocket region.

• Journal of Forest and Environmental Science
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• v.28 no.4
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• pp.263-267
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• 2012

Characteristics of charcoals manufactured in each temperature as 400, 600 800, 1,000 and $1,200^{\circ}C$ were examined. Sapwood and heartwood of Quercus variabilis that one of major species in charcoal materials were used for this experiment. Charcoal density was decreased highly 38-60% compared with wood density and density of sapwood was slightly decreased but heartwood was not changed with increasing carbonization temperature increase. Weight loss of sapwood and heartwood charcoal increased as carbonization temperature increases, and there is no difference between sapwood and heartwood charcoal. Refining degree of sapwood and heartwood charcoal was zero in charring over $800^{\circ}C$. Moisture and ash of sapwood and heartwood charcoal in each carbonization temperature were not differed between sapwood and heartwood. Volatile of sapwood charcoal was slightly higher than that of heartwood, and decreased as carbonization temperature increases. As the carbonization temperature increased, fixed carbon of sapwood and heartwood charcoal increased. Calorific values of charcoal prepared at $600^{\circ}C$ were 7,200-7,300 cal/g and then decreased slightly as carbonization temperature increased.

• Journal of Environmental Science International
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• v.10 no.5
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• pp.373-380
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• 2001

In recent years, the demand of activated carbon has been increasing steadily because of the environmental problems. Among them waste and water treatment and removal of poisonous gas were invorved. Therefore, in this study, activated carbon was made from the waste chinese cabbage and measured the iodine adsorption ability, carbonization yield, and activation yield of the produced activated carbon. The result showed that the carbonization yield was decreased when carbonization temperature was increaed and that the optimal carbonization temperature was $600{\circ}C$. The optimal concentration of NaOH for removing ash in the raw sample was 1~2N. The range of iodine adsorption number of activated carbon using chinese cabbage at $600{\circ}C$. carbonization was 610.82mg/g to 1019.58mg/g. The activation result of carbonization sample showed that the optimal activation condition was the carbonization at $400\circ}C$ and the activation at$700{\circ}C$. So the production of activated carbon using chinese cabbage was possible in the aspect of reuse of resource and decrease of environmental pollution compared to the commercial activated carbon.

• Journal of the Korean Society of Tobacco Science
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• v.23 no.1
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• pp.19-30
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• 2001

This study was carried out to investigate the influences of environmental condition in storage room, moisture content and packing weight of leaf on the carbonization of processed flue-cured leaf tobacco, and find out a regression model able to pre-estimate the degree of carbonization. The influence of temperature and humidity in storage room on the carbonization was high,, while that of packing weight was relatively low, However, high moisture content and packing weight of leaf accelerated the carbonization under the high temperature and humidity condition. Thus the leaf tobacco under the condition of 4$0^{\circ}C$, 7$0^{\circ}C$ R.H. in storage room, 16% moisture content and 286 kg/box of packing weight could be carbonized within one month. The pH, total sugar content, lightness(L) and yellowness(b) of leaf were closely related to carbonization of leaf during storage. There were significant regression and yellowness of leaf. It is considered that the certification and/or pre-estimation of carbonization during storage may be possible by applying the regression equation.

• Carbon letters
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• v.13 no.4
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• pp.226-229
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• 2012

Polyacetylene (PA) films with vertically aligned fibril morphology were synthesized in homeotropic nematic liquid crystal (N-LC) solvent by using a magnetic field of 5 Tesla as an external perturbation. Scanning electron microscope (SEM) photographs indicated that the lengths of fibrils from the substrate were $5-35{\mu}m$, depending on polymerization time. Carbonization was carried out using iodine-doped PA film and a morphology-retaining carbonization method. From the SEM results, we confirmed that the vertical morphology of the PA remains unchanged even after carbonization at $800^{\circ}C$. The weight loss of the films due to carbonization at $800^{\circ}C$ is about 20% of the weight of the film before iodine doping. It is expected that vertically aligned carbon might be a precursor for preparing vertical graphite materials, which materials could be useful for electrochemical energy storage and cell electrodes.