• Journal of Korea Foresty Energy
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• v.22 no.1
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• pp.17-23
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• 2003

Three different aged Chinese bamboo (Phyllostachys pubescense; 3, 5, and 7 years) was carbonized using three different types of kilns (special, improved and simple kiln) and their physicochemical charcoal properties were investigated. The fixed carbon of the bamboo charcoal prepared from the special kiln (800 - $1,000^{\circ}C$) tended to be decreased, while the specific surface area tended to be increased, according to the increase of bamboo ages. The bamboo charcoal prepared from the 5-year-aged showed the highest value in iodine value. In the improved kiln (600 - $700^{\circ}C$), the specific surface area and the iodine value increased with the growth period. In the simple kiln (400 - $500^{\circ}C$), the amount of volatile matter of the bamboo charcoal was approximately two times higher than that obtained from the special and improved kilns. Despite of the high amount of volatile matter in the simple kiln, the fixed carbon was more than 80%. The 5-year-aged bamboo charcoal showed the highest levels in specific surface area and iodine value. The physical properties of the bamboo charcoals prepared from the 3- and 5-year-aged Chinese bamboo were relatively worse those of Korean bamboo of the same ages. It was probably thought caused by less dense structure of the Chinese bamboo of 3- and 5-year-aged than the domestic in morphological aspects.

• Journal of Multimedia Information System
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• v.7 no.2
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• pp.97-106
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• 2020

The subjective experience would degrade the current artificial artistic aesthetic analysis. Since Qiong kiln ceramics have a long history and occupy a very important position in ceramic arts, we employed computer-aided technologies to quickly automatically accurately and quantitatively process a large number of Qiong kiln ceramic images and generate the detailed statistical data. Because the color features are simple and significant visual characteristics, the color features of Qiong kiln ceramics are analyzed for the quantitative aesthetics. The Qiong kiln ceramic images are segmented with GrabCut algorithm. Three moments (1st-order, 2nd-order, and 3rd-order) are calculated in two typical color spaces, namely RGB and HSV. The discrimination powers of the color features are analyzed according to various dynasties (Tang Dynasty, Five Dynasties, Song Dynasty) and various utensils (Pot, kettle, bowl), which are helpful to the selection of the discriminant color features among various dynasties and utensils. This paper is helpful to promoting the quantitative aesthetic research of Qiong kiln ceramics and is also conducive to the research on the aesthetics of other ceramics.

• Journal of the Korean Wood Science and Technology
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• v.30 no.4
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• pp.87-95
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• 2002

Three different species of green and air-dried Korean bamboos were carbonized by using three different types of kilns designated as special (800~1000℃), improved (600~700℃) and simple kiln (400~500℃), and the bamboo vinegars obtained from the carbonization processes were characterized. In the case of the special kiln, most of the bamboo vinegars obtained at the first recovery stage showed high values of specific gravity and also in content of organic acid and water-soluble tar. The bamboo vinegars obtained from the improved kiln showed various physical properties depending on their species. In the case of simple kiln, the bamboo vinegars obtained from air-dried bamboos and at temperatures below 80℃, showed a higher specific gravity and more water-soluble tar as well as total organic components than those obtained at 80~150℃. A good linear relationship (correlation coefficient of ca. 0.90) was obtained between the specific gravities and the sum of organic acids and water-soluble tars. Therefore, this correlation coefficient might be a good index to determine the quality of bamboo vinegars. The major chemical constituents of the bamboo vinegars were acetic acid and considerable amounts of phenols: guaiacol, ethyl guaiacol, syringol, and methyl syringol.

• Journal of the Korean Society of Combustion
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• v.20 no.2
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• pp.14-27
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• 2015

Calcination, which represents thermal decomposition of $CaCO_3$, is the key reaction in a cement process. Some reactions including heating-up also take place simultaneously in the calcination reactors. Basic thermal performance and dimensions of the reactors in two cases, which are a rotary kiln wih a four-stage cyclone pre-heater and a simple single rotary kiln, were compared. To employ the heat transfer, mass transfer and reaction rate as well as calcination, one-dimensional modeling was conducted in each case. Some simplification about the reactors was described, however, the reliable Nusselt number and heat transfer coefficients on the reactors were used to make results reliable.

• Journal of the Korean Society of Combustion
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• v.22 no.4
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• pp.9-18
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• 2017

This paper is to suggest a simple flame model for the analysis of an internal flame of rotary kilns and to present the application cases. Reaction rates in the multi combustion stages of the selected solid fuel were calculated considering the reaction rates with the Arrhenius type equations. In addition, primary and secondary air flow arrangement were considered. As a simple application case, the combustion trends according to the different solid fuels were described. Improved operating conditions as related with the fuel characteristics were shown to be important for the stable combustion characteristics and the performance of the reactors as defined by the exit temperature of the solid materials.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.4
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• pp.61-68
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• 2009

This paper presents the numerical analysis of process of sludge drying to know the characteristics of design parameters and develop the new process plant. Finite volume method and $k-{\varepsilon}$ turbulence model were used to analogy the sludge drying furnace. It has been attempted to perform the disposal of sewage sludge such as simple reclaiming and dumping in sea and incineration. Currently, these methods are restricted by national or international government regulations. The drying process is adopted as an effective method for sewage sludge treatment. However sewage sludge makes it difficult to treat with a large volume at the real drying process plant because of its own complicated physical, chemical, and thermal properties. The final design value of moisture content with 10% of the dried sludge can be obtained through the simulated outputs in this study.

• Journal of Conservation Science
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• v.26 no.3
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• pp.229-245
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• 2010

The pupose of this study was to identify the material characteristics, firing environments and making techniques for the jar coffins from the Oryangdong kiln site and the Ungokdong tomb site in Naju. All jar coffins had very similar physical, mineralogical and geochemical characteristics, although it was excavated from the different sites. The wall thickness of the jar coffins was about 2.3 to 5.3 cm. Under the microscopy, the jar coffins include a large quantity of various quartz with some microcrystalline and showed partly orthoclase and biotite. It is presumed that the mineral sherds added to maintain the thick wall and to control the percentage of contraction during drying and firing of jar coffins and it has contained about 11.4 to 19.8 %. Firing temperature of the jar coffins is estimated as 1,000 to $1,150^{\circ}C$. Also, all jar coffins and soils show similar geochemical behavior of elements and clay-mineralization degree within the site. This indicates making that the soil is probable to be a raw material of the jar coffins. But it shows different characteristics in major elements of soils which is collected at the kiln floor and the trench region of the Oryangdong kiln site because of the lack of quartz and feldspar in the soils. Therefore, it can use of the jar coffins making clay, if it goes through a simple special process such as mixing temper.

• Journal of Korea Foresty Energy
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• v.22 no.2
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• pp.18-25
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• 2003

Bamboo vinegar was prepared from China-grown bamboo (Phyllostachys pubescens) using simple kiln (400 - 500 $^{\circ}C$), and its physical properties and chemical components were investigated and compared to those of Korea-grown bamboo vinegar. The physical properties of China-grown bamboo vinegar were as follows: Baume specific gravity 4.5, organic acid 9.9%, pH 2.8, tar 3.1% and refractive index 13.1%, respectively. The main components of the bamboo vinegar were acetic acid, 1-hydroxyl-2-propanone, methanol, propionic acid, 1-hydroxyl-2- butanone. There was no significant difference between the components of Korea- and China-grown bamboo vinegars. Total organic materials in China-grown bamboo vinegar were 14.8%, and organic acids (acetic acid, formic acid, propionic acid, and butanoic acid) consisted of 9.0%. These acids corresponded to 61% of total organic materials. Neutral and phenolic compounds consisted of 4.5% and 0.8% of the bamboo vinegar, which were correspond to 6% and 31% of total organic materials, respectively. The physicochemical properties of traditional Chinese bamboo vinegar indicated that it was collected at low temperature and aged for a long time.

• Journal of Korea Foresty Energy
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• v.21 no.2
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• pp.1-9
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• 2002

Pine bark was carbonized by using a small-scale experimental kiln and three different types of large-scale kilns (simple (400-$500^{\circ}C$), improved (600-$700^{\circ}C$) and special kiln (800-$1,000^{\circ}C$). The physical properties and pore structures of the bark charcoals prepared were analyzed. When the bark was carbonized at various temperatures ranging from 500 to $900^{\circ}C$in the presence of nitrogen, carbonization yield decreased rapidly with increasing carbonization temperature and it remained constant from 700 to $900^{\circ}C$. The carbonization yield of the bark was 16 - 18% higher than that of pine wood. The BET specific surface areas and iodine values increased with a decrease in carbonization yield. The BET specific surface areas of the bark charcoals reached about 400 -$500m^2／g$ for carbonization yield of 32-40%. The pine wood charcoal prepared at $600^{\circ}C$ for 30 min resulted in a more microporous structure, whereas the bark charcoal prepared at the same condition was more mesoporous. The carbonization yields and physical properties such as iodine values and BET specific surface areas of bark charcoals prepared by using the large-scale kilns were very similar to those of the small-scale kiln. The results indicated that the pine bark could be used as starting material to produce good quality charcoal having a large specific surface area and a high carbonization yield.

• The Korean Journal of Ceramics
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• v.5 no.3
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• pp.296-302
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• 1999

The state of the art of the 2-stage swirl calciner is to make 2-stage counter gas flow in a calciner with cooler hot air. Gas flow in the calciner increases retention time of raw mix particles. Simple structure of the 2-stage swirl calciner operated optimally the rotary cement kiln. In this study, in order to decide the entrance type of the cooler air of the optimal calciner model, an entrance cooler air velocity, the input points of raw mix were analyzed in many aspects with cold model experiment and computational fluidized dynamic simulation. It was found that the entrance type of cooler air fully splite 2-stage for the optimal condition of the cold model calciner. The operation conditions were that the input feeding, the cooler air velocity and the air velocity of throat were 0.33kg/$\textrm m$3$, 15m/s and 20m/s respectively. The performance of 150 t/d the pilot plant connected with the kiln rising duct was that volume capacity of the calciner is over 430 kg/$\textrm m$3$-h, decarbonation rate of raw mix apparently 90%, heat consumption 950 kcal/kg-cli and retention time of raw mix 2.4 sec. Its the best operating condition is cooler air velocity 18m/s, the gas velocity of throat 25m/s, feeding rate of raw mix 10t/h. The operating experience of the pilot plant confirmed the success of scale up for over 3000 t-cli/d.