• Plant Journal
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• v.17 no.2
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• pp.32-41
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• 2021

Recently, air environmental issues such as fine dust have rapidly emerged as national issues, and intensive environmental regulations are being applied to coal-fired power plants. This study introduces the case of improving the performance of desulfurization facilities for removing sulfur oxides and dust, which are the main air pollutant emitters of coal-fired power plants, and conducted four case studies to improve the performance of 1,000 MW power plants currently in operation and carried out construction. Liquid ratio was increased by remodeling the absorption tower of desulfurization facilities, and vaporization reaction was promoted by increasing the flow rate of oxidized air. In addition, the gas heater leakage rate was improved to improve the efficiency of final desulfurization facilities. It is expected that performance improvement work considering harmony with existing facilities will satisfy the regulations(25ppm of sulfur oxides, 5mg/Sm³) that will be applied from 2023, and can be referred to other thermal power plants for review and application.

• Safety and Health at Work
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• v.11 no.3
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• pp.322-334
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• 2020

Background: Spontaneous combustion of coal is one of the factors which causes direct or indirect gas and dust explosion, mine fire, the release of toxic gases, loss of reserve, and loss of miners' life. To avoid these incidents, the prediction of spontaneous combustion is essential. The safety of miner's in the mining field can be assured if the prediction of a coal fire is carried out at an early stage. Method: Adularya Underground Coal Mine which is fully mechanized with longwall mining method was selected as a case study area. The data collected for 2017, by sensors from ten gas monitoring stations were used for the simulation and prediction of a coal fire. In this study, the fuzzy logic model is used because of the uncertainties, nonlinearity, and imprecise variables in the data. For coal fire prediction, CO, O₂, N₂, and temperature were used as input variables whereas fire intensity was considered as the output variable.The simulation of the model is carried out using the Mamdani inference system and run by the Fuzzy Logic Toolbox in MATLAB. Results: The results showed that the fuzzy logic system is more reliable in predicting fire intensity with respect to uncertainties and nonlinearities of the data. It also indicates that the 1409 and 610/2B gas station points have a greater chance of causing spontaneous combustion and therefore require a precautional measure. Conclusion: The fuzzy logic model shows higher probability in predicting fire intensity with the simultaneous application of many variables compared with Graham's index.

• Particle and aerosol research
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• v.10 no.4
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• pp.131-136
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• 2014

The importance of waste treatments is increasing because of the lack of resources and environmental problems resulted from economic growth policy. Especially, the pollutant dust which is one of the wastes should be treated considerately because it could cause secondary damages on the human health as well as environmental systems. Recently, massive amount of coal fly-ash is being produced in thermoelectric power plants. In this study, we compared two general methods used in estimating the amount of unburned carbon in fly-ashes to categorize the coal fly-ashes into several groups following their carbon contents. One is the "loss on ignition(KS L 5405) method" which estimates the change of mass after combustion, and it is generally used. Another one is measuring $CO_2$ gas content by burning solid carbon in the fly-ash, and it is called "$CO_2$ analysis method."

• Tuberculosis and Respiratory Diseases
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• v.47 no.2
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• pp.255-258
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• 1999

Pneumoconiosis, very popular to coal miners who are exposed to coal dusts dominantly, was introduced in the 19th century to describe lung diseases consequent to the inhalation of mineral dusts. Coal workers' pneumoconiosis(CWP) colloquially called "black lung" in the United States, is a distinct pathologic entity resulting from the tissue reaction to deposits of dust include the coal macule, which associated with focal emphysema constitutes the characteristic lesion of simple CWP and complicated CWP or progressive massive fibrosis(PMF). Coal mining are also associated with chronic bronchitis, chronic airflow limitation, and/or generalized emphysema. Progressive massive fibrosis lesions may imprint on and obliterate airways and vessels, and cavitation is not uncommon, being the consequence of ischemic necrosis or mycobacterial infections. We report a case which is unusual form of progressive massive fibrosis to be differentiated from lung carcinoma. It is a rapid growing PMF with ischemic necrosis. By the studies which are about risk of having progressive massive fibroois, it is predicted to be 1.4%. And the other study shows that simple pneumoconiosis clearly predisposed to PMF, with five year attack rates of 13.9%, 12.5%, 4.4% and 0.2% among men with categories 3, 2, 1, and 0 respectively at the start of the risk periods.

• Journal of Preventive Medicine and Public Health
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• v.23 no.3 s.31
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• pp.262-273
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• 1990

In order to assess the method which is more sensitive one to detect the early change of lung tissue by the inhaled dust, we have performed the various medical examinations such as chest radiography, pulmonary function test, high resolution chest CT, brnchoalveolar lavage and lung biopsy used bronchoscope and ultrathin bronchoscopy examination to 48 persons. The control group were 8 persons who did not exposed to dust, 40 cases of the experimental group have professionally exposed to the mineral dust. The results were as follows 1. The total number of cells in bronchoalveolar lavage was significantly increased in all of the pneumoconiosis group classified by chest and high resolution chest CT. 2. The composition rate of macrophage to the total number of cells in bronchoalveolar lavage fluid was significantly decreased in all of the pneumoconiosis group compared with the control group. 3. The composition rate of neutophils and lymphocytes to the total number of cells in bronchoalveolar lavage fluid was significantly increased in all of the pneumoconiosis group compared with the control group. 4. The forced expiratory volume in one second ($FEV_{1-0}$), maximal mid-expiratory flow (MMF), and maximal voluntary ventilation (MVV) were significantly increased only in the group of the progressed pneumoconiosis relatively. 5. We observed submucosal edema, anthracotic pigmentation and granuloma formation in transbronchial lung biopsy of the suspected pneumoconiosis (category 0/1) case which is thought to the early change of coal workers' pneumoconiosis.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.2
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• pp.118-130
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• 2015

Fine dust containing iron compounds is of current interests in metro subway as well as large scale industries including iron manufacturing and smelting works. This work attempts to find a new design of magnetic filter module for iron dust capture. It simulated the vertical rectangular duct with metal mesh which might promote electric fields in the duct space. A lab test using coal fly ash composed of 8.66% Fe with the most form of $Fe_3O_4$ and $Fe_2O_3$ showed capability of magnetic collection. It showed the capture efficiency with 80~93% for $PM_{2.5}$ depending on magnetic intensity. Ferromagnetic wire mesh contributed up to 50% of collection increment.

• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.25-30
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• 2002

This paper demonstrates the effects of dust electrical resistivity on electrostatic precipitability. The effects of gas temperature, velocity and humidity on the collection efficency were considered by used of coal fly ashes from fluidized bed combustion boiler. The experiments for collection efficiency were carried out in the pilot plant. The ashes which have non-spherical geometry and high electrical resistivity were used. Electrical resistivity is an important property for the collection efficiency in the electrostatic precipitators. Fly ash resistivity as a function of temperature up $350{\circ}C$ and water concentration(up to 15%) has been experimentally investigated using the resistivity test equipment consisted of the movable electrode, dust cup, and furnace. As the resistivity of fly ash in the operating temperature($150{\circ}C$) of an electrostatic precipitator was measured higher than $1010{\Omega}{\cdot}$cm, flue gas conditioning in the electrostatic precipitator to reduce the resistivity of fly ash is required.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.2
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• pp.541-541
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• 2018

• Journal of Korean Society of Environmental Engineers
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• v.29 no.12
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• pp.1400-1403
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• 2007

• Korean Chemical Engineering Research
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• v.48 no.1
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• pp.116-120
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• 2010

$CO_2$ is regarded as one of the greenhouse gases(GHG), which is the main reason of climate change. In order to achieve lower $CO_2$ emissions, several efforts have been conducted worldwide. $CO_2$ capture & storage(CCS) technology development is needed for a coal-fired combustion power plant because of huge $CO_2$emission. Oxy fuel combustion, one of the CCS technologies has been considered as a primary concern, nowadays. Oxy-fuel combustion needs flue gas recirculation(FGR) for stable operation and enrichment of $CO_2$ concentration in the flue gas. FGR adoption for oxy-fuel combustion requires development of effective desulfurization and dust removal technology. In this study, desulfurization characteristics of lime and dust removal technology have been researched in the laboratory scale coal combustor.