• Journal of Energy Engineering
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• v.18 no.4
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• pp.239-246
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• 2009

A fundamental investigation has been conducted on the combustion of single particle of a sub-bituminous coal char burning at different temperatures and residence times. The lab-scale test setup consisted of a drop tube furnace where gas temperatures varied from $900^{\circ}C$ to $1400^{\circ}C$. A calibrated two color pyrometer, mounted on the top of the furnace, provided temperature profiles of luminous particle during a char oxidation. An amount of char mass reacted during the reaction is measured with thermogravimetry analyzer by using an ash tracer method. As a result, mass and area reactivity as well as reaction rate coefficients are determined for the char burning at atmospheric pressure condition.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.61-66
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• 1998

An artificial zeolite was synthesized from bituminous coal fly ash by thermo-alkali treatment, $100{\pm}3^{\circ}C$ and 3.5 N NaOH solution for 24 hours, to develope new useful material in waste water treatment system. The artificial zeolite had much higher cation exchange capacity, $299cmol^+\;kg^{-1}$ and lower concentration of extractable heavy metals than bituminous coal fly ash. The higher the temperature and the longer the shaking time, the more Zn, Cu, Cd and Pb were sorbed chemically by the artificial zeolite. Shaking artificial zeolite and wastewater at $35^{\circ}C$ for 9 hours, the amount of sorbed heavy metals were $123.5g\;kg^{-1}$ for Zn, $164.7g\;kg^{-1}$ for Cu, $184.4g\;kg^{-1}$ for Cd and $350.6g\;kg^{-1}$ for Pb, respectively.

• Asian Journal of Atmospheric Environment
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• v.6 no.1
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• pp.67-72
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• 2012

The chemical characterization of water-soluble organic carbon in ash emitted from a coal combustion boiler has not been reported yet. A total of 5 ash samples were collected from the outlet of an electrostatic precipitator in a commercial 500 MW coal-fired power plant, with their chemical characteristics investigated. XAD7HP resin was used to quantify the hydrophilic and hydrophobic water-soluble organic carbons (WSOC), which are the fractions of WSOC that penetrate and remain on the resin column, respectively. Calibration results indicate that the hydrophilic fraction includes aliphatic dicarboxylic acids and carbonyls (<4 carbons), amines and saccharides, while the hydrophobic fraction includes aliphatic dicarboxylic acids (>4-5 carbons), phenols, aromatic acids, cyclic acid and humic acid. The average mass of the WSOC in the ash samples was found to depend on the bituminous coal type being burned, and ranged from 163 to 259 ${\mu}g$ C/g of ash, which corresponds to 59-96 mg C of WSOC/kg of coal combusted. The WSOC mass accounted for 0.02-0.03 wt% of the used ash sample mass. Based on the flow rate of flue gas produced from the combustion of the blended coals in the 500 MW coal combustion boiler, it was estimated that the WSOC particles were emitted to the atmosphere at flow rates of 4.6-7.2 g C/hr. The results also indicated that the hydrophilic WSOC fraction in the coal burned accounted for 64-82% of the total WSOC, which was 2-4 times greater than the mass of the hydrophobic WSOC fraction.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.443-450
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• 2008

Efficient use of low rank coals (LRC) have been investigated as a method to cope with recent high oil price. Among the coals used in industry, lignite and sub-bituminous coals are belong to the LRC, and have abundant deposit and are distributed worldwide, but high moisture contents and self ignition properties inhibits their utilization. In this paper, chemical coal cleaning to produce ash-free coal from LRC has been investigated. Two technologies, that is, UCC(Ultra Clean Coal) process removing ash from coal and Hyper Coal process extracting combustibles from coal were compared with. UCC process has merits of simple and reliable when it compared with Hyper Coal process, but the remaining ash contents werehigher than Hyper Coal. Hyper Coal has ash contents under the 200ppm when raw coal is treated with appropriate solvent and ion exchange materials to remove alkali materials in extracted solution. The ash-free coal which is similar grade with oil can be used as alternate oil in the industry, and also used as a high grade fuel for IGCC, IGFC and other advanced combustion technology.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.3
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• pp.249-254
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• 1992

This research was conducted to investigate the effects of fly ash applications on growth and yield parameters of corn (Zea mays L.), and soil chemical properties. Corn height at silking stage, and height and dry matter ratio at harvesting stage were enhanced by applications of fly ashes derived from bituminous coal and anthracite, respectively. Effects of fly ash treatment on growth parameters of corn were varied with kinds and levels of fly ash application and growth periods, but relatively small without revealing a major negative effect as compared to the control. Yield of corn was increased by applying fly ash of anthracite origin, but other yield components were not influenced negatively by fly ash treatment. Soil total carbon contents, cation exchange capacity, and phosphorus contents of soils sampled after harvest of corn were significantly increased by fly ash treatment, although there were slightly different effects according to kinds and levels of fly ash application. Exchangeable cations of soils were varied within an experimental error range. Phosphorus taken up by corn was enhanced by treating fly ash of the bituminous coal to the soil and there were a positive correlation between phosphorus uptake and soil Phosphorus level. Cation uptake by corn was changed a little, but no significant reduction was observed in cation uptake due to fly ash treatment. It seems to be difficult to figure out the mechanism of fly ash effects on growth and nutrient uptake by corn with one year field experiment, however treatment of fly ash enhanced some parameters of growth and yield, and nutrient uptake by corn without revealing any major negative effects. To determine the value of fly ash as a fertilizer source, continuous researches under various soil and crop conditions were considered to be necessary.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.230-233
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• 2008

The vanadium rich ash of petroleum coke can give a slagging problem during because of the high melting point of $V_2O_3$. For continuous removal of the slag, petroleum coke is often mixed with coal, and the viscosity of the mixed slag is an important property, determining the gasification temperature. The viscosities of the mixed slag from various mixing ratios of petroleum coke and a bituminous coal were investigated. When mixed with a crystalline coal slag, $T_{cv}$ was increased at a higher the coke content in the mixed feed. When the $V_2O_3$ concentration was greater than 4.5%, it was difficult to get accurate measurements of $T_{cv}$. The SEM/EDX analyses of the cooled slag revealed that the major crystalline phase was anorthite, and $T_{cv}$ should be related to the formation temperature of anorthite. The SEM/EDX analyses also showed that, at low concentrations of vanadium, part vanadium formed a crystalline phase with Al-Si-Ca-Fe, and the rest remained in the glassy phase, suggesting that vanadium existed as a slag component at the low viscosity region. At a high concentration, vanadium forms a phase with Ca, and the Ca-V phase was separated from the slag phase, and formed a layer above the slag. FeO in petroleum coke also played an important role determining viscosity: at high temperatures, increased FeO lowered the viscosity, but as it formed a spinel phase, the depletion of FeO in the slag resulted in a higher viscosity.

• Applied Chemistry for Engineering
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• v.5 no.2
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• pp.337-344
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• 1994

Two coals which have a quite different properties were selected to compare the combustion characteristics in a cyclone combustor. The capacity of the combustion test rig is about 75kW and total volume is 5.7 liters. The pulverized sample coals are well burned from fuel rich(air ratio 0.4) to fuel lean(airs ratio 1.6). Two different property coals show quite different patterns of ash collection in slag pot, dust separator and combustion chamber. Combustion temperature of subbituminous coal is about $100^{\circ}C$ lower than bituminous coal at the entire region, and in case of bituminous coal, hot spot appeared at the lower part and axial line of the combustion chamber.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.4
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• pp.717-725
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• 1989

An experimental investigation on the combustion behavior of pulverized coal particles was performed using the cross-section micrography techniques while sample coal particles were collected in-situ from the flow reactor. The coal particles were representative of pulverized bituminous coal undergoing a raped pyrolysis and combustion, however, quenched at the time when the particles were deposited onto a sample plate. The internal structure of coal was observed to change as deposited. Upon injection into a flow reactor, bituminous coal particles showed many holes which represented internal pore formation during the pyrolysis. The relative portion of the remaining matrix of coal was decreasing as the residence time progressed. This direct observation of cross-section of burning particles enabled better understanding of the coal combustion behavior.

• Economic and Environmental Geology
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• v.28 no.2
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• pp.147-154
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• 1995

Coal fly ashes collected from the Samcheonpo and the Seocheon Power Plants were analyzed for major and minor components and heavy metals such as As, Cd, Co, Cr, Cu, Ga, Hg, Mo, Ni, Pb, Sb, V and Zn in order to suggest basic data to apply coal fly ash as fertilizer or soil ameliorator. The specific gravity of the samples was less than 2.0, and amounts of organic matter range from 5.0% to 12.3%. The identified minerals by XRD were mainly quartz, mullite and pyrite in anthracite coal, and mainly quartz and mullite in bituminous coal. Generally, the contents of heavy metal elements analyzed were lower less than those of soil, though higher in some samples. Element couples of some elements( e.g., As-Mo, Zn ; Mo-As, Sb, V, Zn ; Sb-Zn ) show positive correlations with each other, but the high correlations of toxic elements such as As, Pb, Cd and Hg indicate to give attention to apply coal fly ash as fertilizer or soil ameliorator.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.182-188
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• 2008

The compounds of recycled polyethylene(PE) and fly-ashes were prepared. Polymers used were sorted PE from mixed plastics of household waste and Low Density Polyethylene(LDPE) and Linear Low Density Polyethylene(LLDPE) recycled from the scrap of packaging film plants. Fly-ashes were from the power plant and from the household waste incinerator. The tensile strength of recycled LDPE and LLDPE compounds decreased and the flexural modulus increased with greater amount of the power plant fly-ash. Anthracite fly-ash gave rise to slightly higher tensile and flexural strength of the LLDPE mixtures than bituminous coal fly-ash presumably due to higher content of unburned carbon. The incinerator fly-ash introduced to household waste PE enhanced both tensile strength and flexural modulus of the compounds. When LDPE and household waste PE were used together, the synergistic effect of incinerator fly-ash to household waste PE was offset by reduced crystallization of LDPE due to the filler particle. The compounds of household waste PE and incinerator fly-ash might be applied to structural materials for such as sewage pipe, which reduces the waste treatment cost and conserve the environment and resources.