• Journal of Environmental Health Sciences
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• v.36 no.2
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• pp.128-135
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• 2010

The main purpose of this study was to develop the greenhouse gas emission factor for power plant using sub-bituminous coal. In Korea, Fired power plant are a major source of greenhouse gases within the fossil fuel combustion sectors, thus the development of emission factors is necessary to understand the characteristics of the national specific greenhouse gas emission and to develop nation specific emission factors. These emission factors were derived from the $CO_2$ concentrations measurement from stack and fuel analysis of sub-bituminous coal. Caloric value of sub-bituminous coal used in the power plants were 5,264 (as received basis), 5,936 (air-dried basis) and 6,575 kcal/kg (dry basis). The C emission factors by fuel analysis and $CO_2$ concentration measurement was estimated to be 26.7(${\pm}0.9$), 26.3(${\pm}2.8$)tC/MJ, respectively. Our estimates of C emission factors were comparable with IPCC default value.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.111-114
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• 2012

The ignition behavior of single coal particles of five kindes of coal with different ranks (low volatile bituminous, low volatile sub-bituminous, high volatile bituminous, lignite) with particle size of $150-200{\mu}m$ was investigated at high heating rate condition. Particles were injected into a laminar flow reactor and the ignition behavior was observed with high speed cinematography. Sub-bituminous were observed to ignite homogeneously; however, low volatile bituminous coal and lignite undergo fragmentation prior to igntion. The observation was analyzed with previous work.

• Journal of the Korean Society of Combustion
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• v.16 no.1
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• pp.22-29
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• 2011

This paper focuses on the combustion characteristics of blended coals with bituminous and sub-bituminous coals under air and oxy-fuel combustion conditions. The effects of oxygen concentration and blending ratio on the combustion characteristics were experimentally investigated using a thermogravimetric analyser (TGA). Characteristic temperatures including ignition, burnout temperature and activation energy were determined from TG and DTG combustion profiles. As oxygen concentration increased and the presence of sub-bituminous coal, characteristic temperatures and activation energy decreased. The ignitability, reactivity and kinetics have all been greatly improved under oxy-fuel combustion conditions. Based on this, co-firing with bituminous and sub-bituminous coals under oxy-fuel combustion conditions may be suggested as an alternative method to the fuel flexibility and cost-effective power production with carbon capture and sequestration.

• Journal of Conservation Science
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• v.29 no.4
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• pp.345-354
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• 2013

This study analyses geochemistrical, microscopic, mineralogical characteristics of coals which have been collected from in and out of the shipwreck No 1 of Mado island during underwater excavation in Taean. The result from mineralogical and geochemical analysis reveals that the specific gravity of the coals is $1.28g/cm^3$. Considering that coals contains 10% mineral of it and the specific gravity of the pure is $1.15g/cm^3$, it is believed that the collected coals would be lignite or biturminous coal. The X-ray diffraction analysis which displays the peak of $2{\theta}$ is 20~25C degree, proves that the collected coals would be categorised as low rank coal. The collected coals is composed of: 93%-94%(93.5%) of vitrinite maceral group, 5%-6%(5.5%) of exinite maceral group, and 1% of inertinite maceral group. In addition, the average of reflection rate is $R_{mean}$: 0.627 showing that it would be either high volatile bituminous C coal or sub-bituminous C coal. Such result confirms that the coal is sub-bituminous C or high volatile bituminous C coal in accordance with the U.S Bureau of Mine(USBM) classification system. The element analysis reveals that the coal is the coking coal which is grouped as the bituminous coal. Comparative analysis between the coals of Mado Shipwreck No 1 and domestic coals shows that the coals of Mado Shipwreck is similar to the bituminous coal used in the area of Janggi in Pohang city.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.2
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• pp.151-160
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• 2010

Particles emitted from three coal-fired power plants burning bituminous and sub-bituminous coals were examined for PM and size fractions PM>2.5 and PM2.5. The ratio of PM2.5/PM was ranged from 10 to 62%, and PM emission increased with the amount of coal feed, which was 7.23~15.66 kg/h. The emission range of PM2.5 from three power plants was 1.24~4.48 kg/h (dry), which was function of the mixed rate of viscous sub-bituminous coal in feed. Of course such effect should be examined by further tests in details. Based on the consumed coal and thermal load, the emission factors averaged were shown as 59.03 g-PM/ton-coal, 14.79 g-PM2.5/ton-coal and 22.51 g-PM/MWh, 5.54 g-PM2.5/MWh, respectively.

• Journal of the Korean Society of Combustion
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• v.15 no.4
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• pp.65-73
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• 2010

In order to provide fundamental information for developing reaction model in the practical blended coal power plants, effects of particle size and blending ratio on combustion characteristics and thermal reaction in co-firing with bituminous and sub-bituminous coals were experimentally investigated using a TGA and a laboratory-scale burner. Characteristic parameters including ignition, burnout temperature and activation energy were determined from TG and DTG combustion profiles. Distributions of flame length and mean particle temperature were investigated from the visualization of flames in slit-burner system. As coal particle size decreased and volatile matter content increased, characteristic temperatures and activation energy decreased. The ignition/burnout characteristics and activation energy are linearly influenced by a variation in particle size and blending ratio. These results indicated that the control of the coal blending ratio can improve the combustion efficiency for sub-bituminous coals and the ignition characteristics for bituminous coals.

• Journal of the Korean Society of Combustion
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• v.18 no.4
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• pp.53-58
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• 2013

Lots of Coal power plants (about 30) using bituminous coals are being run in Korea. The use of high volatile low grade sub-bituminous coal is increasingly extended because of imbalance between the worldwide coal supply and demand. Mill-fire has been an important issue since the use of such sub-bituminous coal. In existing coal plants of Korea, shutdown of coal and air supplies could be only a way, and an alternative has not been found in suppressing the mill fire. The inside fowfield in the mills has a highly fuel-rich, low temperature, and high velocity and non-reactive such that it could be a nonreactive system essentially. Nevertheless, occasional fire-occurrence could be attributed to the existence of an ignition source. However it has not been so far investigated in detail. The current work has a focus on suppressing the mile fire via some parametric experimental study such as effects of temperature, residence time, ignition source, and inert gas mixing. The results show that an small amount of $CO_2$- or $N_2$-mixing with air is very effective in suppressing fire formation even at high temperatures or flying sparks. The results suggest that exhaust gas recirculation into the mill should be an alternative to suppress mill fire.

• 한국연소학회:학술대회논문집
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• 1999.10a
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• pp.27-46
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• 1999

Combustion test on two kinds of Indonesian sub-bituminous coals of single and blended with bituminous coal imported for power generation was carried out by using the test furnace at KEPRI. The main items of combustion test were temperature profiles of the inside furnace, the yield of unburned carbon, environmental pollution emissions, slagging/fouling tendency, and the comparison of heat loss of furnace. The test results showed that low sulfur and ash content characterized by the Indonesian coals were advantageous to environmental aspect, but high tendency of heat loss and slagging/fouling were disadvantageous to boiler operation. From the results, the necessity of proper coal blending to compensate these weak points was recommended.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.107-109
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• 2012

In Korean coal power plants, rising coal prices have recently led to the rapid utilization of low lank coals such as sub-bituminous coal with low calorific values and low ash fusion temperatures. Using these coals beyond the design range has resulted in important issues including slagging and fouling, which cause negative effects in boiler performances and unstable operations. The purpose of this study is to observe slagging and fouling characteristics resulted from burning various ranks of pulverized coals. We have tested 3 different coals: FLAME(bituminous), KCH(sub-bituminous) and MOOLARBEN(bituminous)coals in the pilot system $50kW_{th}$ scale. A stainless steel tube with preheated air inside was installed in the downstream in order to simulate water wall. Collected ash on the probe and the slag inside the furnace near burner were analyzed by SEM (scanning electron microscopy) to verify the formation degree, surface features and color changes of the pasty ash particles. Induced coupled plasma and energy dispersive X-ray spectroscopy were also performed to figure out the chemical characteristics of collected samples. As a result, KCH was observed that more slag was developed inside the walls of the furnace and on the probe than the other two kinds of coals, as shown in the calculate slagging and fouling indices as well.

• Plant Journal
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• v.18 no.1
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• pp.55-61
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• 2022

In this study, I analyzed the effect of slagging caused by blending bituminous coal and subbituminous coal while maintaining the generator output, combustion conditions, and ventilation conditions for 870MW thermal power plant designed with bituminous coal. Accordingly I proposed an acceptable method of blending coal method. the blending ratio of sub-bituminous coal was adjusted to 10%, 20%, 40%, 60%, 80%, etc. to confirm ultimate analysis, proximate analysis, ash fusion temperature change, slagging indices, etc. Proper blending coal conditions are blending with sub-bituminous coal at 40% or less, ratio of base component to acid component(B/A) is 0.4 or less or 1 or more, total alkali(TA) is 3.5 or less, fusion slagging index(Rfs) is 1,345℃ or more, and ash content is 13% or less in ultimate analysis, the ash content in proximate analysis is 15% or less, and the initial deformation temperature(IDT) should be at least 1,200℃ or more