• 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.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.7
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• pp.675-681
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• 2012

The char oxidation characteristics of ashless coal with a relatively low ash content and high heating value were experimentally investigated at several temperatures (from $900^{\circ}C$ to $1300^{\circ}C$), in various oxygen concentrations (from 10% to 30%) under atmospheric pressure in a drop tube furnace. The char reaction rate was calculated from the exhaust gas concentrations (CO, $CO_2$) measured by FT-IR, and the particle temperature was measured by the two-color method. In addition, the activation energy and pre-exponential factor of ashless coal char were also calculated based on the Arrhenius equation. The results show that higher temperature and oxygen concentration result in a higher reaction rate of ashless coal, and the activation energy of ashless coal char is similar to that of bituminous coal.

• Journal of Energy Engineering
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• v.22 no.2
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• pp.96-104
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• 2013

Coal gasification is considered as one of the best alternatives among clean coal technology and new concept next generation technologies are under being developed to achieve low cost as well as high efficiency. In this study we have developed double swirl multi-burner as part of the development of low cost compact gasifier. We installed new concept multi-burner with pulverized coal distributor to the body of existing gasifier for burner test. Gasification test was performed under the condition of $6.4{\sim}7.2kg/cm^2$ and $1170{\sim}1300^{\circ}C$ by using Indonesian ABK (sub-bituminous) coal to get operation condition of new concept multi-burner. Our interest was focused to ensure a stable operating condition rather than the gasifier performance evaluation. As a result, we were able to achieve the carbon conversion of 84% and the cold gas efficiency of 52.1% at the stable operating conditions.

• Korean Chemical Engineering Research
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• v.48 no.1
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• pp.80-87
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• 2010

Lignite of low rank coal and petroleum coke of high sulfur content can be high potential energy sources for coal gasification process because of their plentiful supply. The kinetic study of steam gasification has been performed in an atmospheric thermobalance with wood chip, lignite, bituminous, anthracite, pet-coke. The effects of gasification temperature($600{\sim}850^{\circ}C$) and partial pressure of steam(30~90 kPa) on the gasification rate have been investigated. The modified volumetric reaction model was applied to the experimental data to describe the behavior of carbon conversion and to evaluate the needed kinetic parameters. Lignite and wood chip with high volatile content showed high average gasification rates comparing to other fuel and thus they might be proper fuel for gasification processes. The activation energies for wood chip, lignite, bituminous, anthracite, and pet-coke through Arrhenius plot were found to be 260.3, 167.9, 134.6, 82.2, 168.9 kJ/mol, respectively. The expression of apparent reaction rates for steam gasification of various chars have been proposed as basic information for the design of coal gasification processes.

• Safety and Health at Work
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• v.8 no.3
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• pp.296-305
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• 2017

Background: Surfactant-containing water sprays are commonly used in coal mines to collect dust. This study investigates the dust collection performance of different surfactant types for a range of coal dust particle sizes and charges. Methods: Bituminous coal dust aerosol was generated in a wind tunnel. The charge of the aerosol was either left unaltered, charge-neutralized with a neutralizer, or positively- or negatively-charged using a diffusion charger after the particles were neutralized. An anionic, cationic, or nonionic surfactant spray or a plain water spray was used to remove the particles from the air flow. Some particles were captured while passing through spray section, whereas remaining particles were charge-separated using an electrostatic classifier. Particle size and concentration of the charge-separated particles were measured using an aerodynamic particle sizer. Measurements were made with the spray on and off to calculate overall collection efficiencies (integrated across all charge levels) and efficiencies of particles with specific charge levels. Results: The diameter of the tested coal dust aerosol was $0.89{\mu}m{\pm}1.45$ [geometric $mean{\pm}geometric$ standard deviations (SD)]. Respirable particle mass was collected with $75.5{\pm}5.9%$ ($mean{\pm}SD$) efficiency overall. Collection efficiency was correlated with particle size. Surfactant type significantly impacted collection efficiency: charged particle collection by nonionic surfactant sprays was greater than or equal to collection by other sprays, especially for weakly-charged aerosols. Particle charge strength was significantly correlated with collection efficiency. Conclusion: Surfactant type affects charged particle spray collection efficiency. Nonionic surfactant sprays performed well in coal dust capture in many of the tested conditions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.3
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• pp.207-213
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• 1992

In this study, the strength and durability of compacted coal ash with proper mixing ratio of fly ash to bottom ash, such as 5:5 or 6:4, are examined for use of highway embankment and subgrade materials. Right after compaction, the strength of bituminous mixed coal ash is greater than that of anthracite mixed coal ash. The distinguished increase of strength with curing time is observed only in Ho-nam mixed coal ash that contains a lot of free lime, and the strength increase with curing time are not seen or little in the others. The durability in sinking test is good also in Ho-nam mixed coal ash, but satisfactory by adding 2% cement in the others. And it is seen that the effects of the strength increase with adding cement are greater in coal ash with proper mixing ratio than in fly ash or bottom ash respectly.

• Journal of Korean Society for Atmospheric Environment
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• v.2 no.1
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• pp.103-110
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• 1986

Since sulfur dioxide is released from the oxidation of sulfur in fuel, the level of $SO_2$ in industrial areas can be effectively managed by optimizing the allocation of fuels: the fuel should be allocated to each industries so as to achieve the air quality goal in the area with minimum fuel cost. The solution for this can be by solved using linear programming technique incorporated with the Gaussian dispersion equation. When this method was applied in Ulsan Industrial Complex, 39.3% of fuel expense could be saved compared with the present uniform fuel policy. With this method, bituminous coal generally was allocated to big emission sources such as power plants or to industries sparsely located in remote areas, and LPG or low-sulfur oils to small or medium-size sources in dense indurstrial aras. However, the particulates emission will increase with this policy, because it maximizes the use of coal within the limit to achieve the air quality goal in the area.

• Korean Chemical Engineering Research
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• v.49 no.5
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• pp.639-643
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• 2011

Fry-drying of coal slurry is one of the upgrading low rank coal processes. It consists of slurry mixing, slurry dewatering, solvent recovery and briquetting. Cost estimation and economic feasibility are examined for the upgrading low rank coal process based on capacity of 1 million ton/yr. In case that investment costs are $100,000,000, discount rate is 12%, and service life is 20 years, the results of economic analysis are enough to satisfy the evaluation criteria of investment such as IRR, B/C ratio, NPV and discounted payback period. According to sensitivity analysis, investment value are very sensitive to raw material cost and product price. Since the bituminous coal price is currently soaring, it is expected that the investment value will increase more and more.

• Journal of Energy Engineering
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• v.20 no.4
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• pp.346-352
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• 2011

The experiment was designed to study the char oxidation kinetics of pulverized coals commonly utilized in Korean power plants. The kinetics has been estimated using the Semenov's thermal spontaneous ignition theory adapted to coal char particle ignition temperature. The ignition temperature of coal char particle is obtained by a direct measurement of the particle temperature with photo detector as well as by means of a solid thermocouple which is used as both a heating and a measuring element. The ignition temperatures for subbituminous coal, Wira, and bituminous coal, Yakutugol, have been measured for 4 sizes in the range of 0.52-1.09 mm. The ignition temperature of the particle increases with the increasing diameter. The results were used to calculate the activation energy and the pre-exponential factor. As a result, the kinetic parameters are in an agreement with ones reported from other investigations.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.2
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• pp.189-195
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• 2008

We developed emission factors for alternative fuels used in cement industries in Korea and also estimated reduction in emissions of greenhouse gas (GHG) by the use of alternative fuels. Emission factors for GHG of waste tire, waste plastic, waste oil and RDF were estimated to be about 89, 78, 77 and 95 ton $CO_2$/TJ respectively. When compared with previous studies, most of the results showed similar trends. The calorific value estimation and elemental analysis for energy source were implemented in order to estimate the exact emission factors and the reduction of GHG emissions using alternative fuel. In the case of 'A' company, $CO_2$ emission from alternative fuels was about 4% lower than that of bituminous coal only. Also in case of company 'B', $CO_2$ emission from alternative fuels was about 1.4% lower than that of only bituminous coal. In Germany and Japan, alternative fuel is not regarded to be fuel consumption in cement industry. When applying this rule, the emission reductions were about 4.3% for company 'A' and 6.3% for company 'B'. The results of this study may be considered as a useful information for developing strategies in reducing GHG emissions.