• Journal of the Korean Institute of Gas
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• v.12 no.2
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• pp.1-6
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• 2008

For the safety design and operation of many gas process, it is necessary to know certain explosion limit, flash point, autoignition temperature (AIT) and minimum oxygen concentration of handling substances. Also it is necessary to know explosion limit at high temperature and pressure. In this study for the safe handling of hydrogen, explosion limit and AIT of combustion properties for hydrogen were investigated. By using the literatures data, the lower and upper explosion limits of hydrogen recommended 4.0 vol% and 77.0 vol%. Also the AIT of hydrogen with ignition sources recommended $400^{\circ}C$ at the electrically heated crucible furnace (the whole surface heating) and recommended $640^{\circ}C$ at the local hot surface. The new equations for predicting the temperature and the pressure dependence of the explosion limits of hydrogen are proposed. The values calculated by the proposed equations were a good agreement with the literature data.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.930-940
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• 2013

We evaluated contamination with organic matter and trace metals by analyzing grain size, ignition loss (IL), chemical oxygen demand (COD), acid volatile sulfide (AVS), and trace metals (Al, Fe, Cu, Pb, Zn, Cd, Ni, Cr, Mn, Hg, and As) in surface sediments at 28 stations around the Geum River estuary in July 2008. The surface sediments in the estuary were mainly composed of coarse sediment (sand and muddy sand), with mean grain size (Mz) ranging between $2-4{\O}$. The high concentrations of IL, COD, and trace metals were mainly found at stations in front of the Gusan outer port and industrial complex, and near the Seocheon coast with relatively fine sediments. In addition, the concentrations of IL and all trace metals, except Pb and As, showed good positive correlations with Mz, indicating that the concentrations of organic matter and trace metals were mainly dependent on sediment grain size. The concentrations of COD, AVS, and trace metals in most sediments did not exceed the sediment quality guideline (SQGs). Although the sediments in the study region are not polluted with organic matter and trace metals, there are many point sources of pollutants, such as Gusan port and industrial complex, Janghang refinery, and a thermoelectric power plant around the Geum River estuary. Thus, the management of coastal environments through periodic monitoring of organic matter and trace metals is required in the future.

• Journal of the Korean Wood Science and Technology
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• v.51 no.3
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• pp.207-221
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• 2023

The increasing demand for clean energy requires considerable effort to find alternative energy sources, such as briquettes. This research aims to develop a charcoal briquette with added pine resin (API) that has excellent combustion speed and distinctive aroma. Briquettes are composed of charcoal, pine resin (concentration: 0%-30%), and starch (up to 7%). They are produced in several stages, including coconut shell pyrolysis in conventional combustion, to obtain charcoal for the briquette precursor. Briquette compaction is conducted by mixing and densifying the charcoal, pine resin, and starch using a hydraulic press for 3 min. The hydraulic press has a total surface area and diameter of 57.7 cm² and 3.5 cm, respectively. The briquettes are dried at different temperatures, reaching 70℃ for 24 h. The study results show that the briquettes have a thickness and diameter of up to 2 and 3.5 cm, respectively; moisture of 2.18%-2.62%; ash of 11.61%-13.98%; volatile matter of 27.15%-51.74%; and fixed carbon content of 40.24%-59.46%. The compressive strength of the briquettes is 186-540 kg/cm². Their calorific value is 5,338-6,120 kcal/kg, combusting at a high speed of 0.15-0.40 s. The methoxy naphthalene, phenol, benzopyrrole, and lauryl alcohol; ocimene, valencene, and cembrene are found in the API. The API briquette has several chemical compounds, such as musk ambrette, ocimene, sabinene, limonene, 1-(p-cumenyl) adamantane, butane, and propanal, which improve aroma, drug application, and fuel production. Accordingly, API briquettes have considerable potential as an alternative energy source and a health improvement product.

• Architectural research
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• v.24 no.2
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• pp.21-27
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• 2022

For the past decade, South Korea had experienced catastrophic building fires, which resulted in consider-ably high number of casualties. This motivated research to develop fire-safe wall assemblies. In this study Fire Risk Analysis (FRA) is conducted as part of the project designing phase to ensure fire safety of the final product. Traditional approach was to consider fire performance at the end of the designing stage, when PASS/FAIL fire test results are required to be submitted to the Authority Having Jurisdiction (AHJ). By applying a fire risk analysis to guide the designing phase, overall fire safety of a wall assembly can be achieved more systematically as conducting FRA allows designers to clearly identify elements that are more vulnerable to fire and simply replace them with other practical options. Severity of fire risk is determined by considering the fire hazards of a wall assembly such as the exterior layer, insulation, vertical connectivity, and external ignition sources (e.g., photovoltaic panels). Frequency of fire risk is assessed based on the factors affecting fire likelihood, which are air cavity and fire-stopping applied in the design, and random design changes occurring during on-site construction. Fire risk matrix is proposed based on these fire risk factors and efforts to reduce the fire risk level associated with the wall assembly are given by systematically assessing the fire risk factors identified from fire risk analysis. Current study demonstrates how fire risk analysis can be applied to develop fire-safe walls by reducing the relevant fire risks- both severity and frequency.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.1
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• pp.83-87
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• 2008

We have a lot of interest in alternative fuels to provide energy independence from oil producing country and to reduce exhaust emissions for air pollution prevention. Biodiesel, which can be generated from natural renewable sources such as new or used vegetable oils or animal fats, may be used as fuel without change of engine structure in diesel engine of compression ignition engine. In this paper, the test results on specific fuel consumption and exhaust emissions of neat diesel oil and biodiesel blends(10 vol.% biodiesel and 20 vol.% biodiesel) were presented using four stroke, direct injection diesel engine. Especially this biodisel was produced from rape oil at our laboratory by ourselves. This study showed that specific fuel consumption and NOx emission were slightly increased, on the other hand CO emission and Soot were tolerably decreased more in the case of biodiesel blends than neat diesel oil.

• Fire Science and Engineering
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• v.33 no.6
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• pp.43-52
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• 2019

A walk-down procedure for fire modeling of nuclear power plants, based on deterministic fire protection requirements, was developed. The walk-down procedure includes checking the locations of safety shutdown equipment and cables that are not correctly indicated on drawings and identifying the existence and location of combustibles and ignition sources. In order to verify the performance of the walk-down procedure developed in this study, a sample of important equipment and cables were selected for hypothetical multiple spurious operation (MSO) scenarios. In addition, the hypothetical fire modeling scenarios were derived from the selected safe shutdown equipment and cables and an actual walk-down was conducted. The plant information collected through the walk-down was compared to the information obtained from the drawings, so that the collected information may be used as input values for the fire modeling.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.6
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• pp.69-78
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• 2010

As part of preliminary study for development of 1,200 N-class bipropellant rocket engine with the concentrated hydrogen peroxide, bipropellant engine elements were designed and experimentally tested. The catalysts of $MnO_2$ and $MnO_2$ added Pb as an additive were compared to achieve high decomposition performance and the catalytic reactor with $MnO_2$ added Pb was designed and its decomposition efficiency of 97.2% was achieved. The autoignition tests of kerosene by decomposed hydrogen peroxide were carried out under various equivalence ratios to ignite without additional ignition sources. Autoignition were achieved in all experimental conditions and $C^*$ efficiencies at each condition were at or above 90%. From the measured thrust results, the highest value was 830 N which is in corresponds with 1,035 N at vacuum level assuming $C^*$ efficiency equals $I_{sp}$ efficiency.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.156-164
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• 2010

As part of preliminary study for development of 1,200 N-class bipropellant rocket engine with the concentrated hydrogen peroxide, bipropellant engine elements were designed and experimentally tested. The catalysts of $MnO_2$ and $MnO_2$ added Pb as an addictive were compared to achieve high decomposition performance and the catalytic reactor with $MnO_2$ added Pb was designed and its decomposition efficiency of 97.2% was achieved. The autoignition tests of kerosene by decomposed hydrogen peroxide were carried out under various equivalence ratios to ignite without additional ignition sources. Autoignition were achieved in all experimental conditions and $C^*$ efficiencies at each condition were at or above 90%. From the measured thrust results, the highest value was 830 N which is in corresponds with 1,035 N at vacuum level using 94.1% theoretical $I_{sp}$.

• Fire Science and Engineering
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• v.23 no.5
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• pp.72-77
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• 2009

In the recycling procedure of the refrigerator, the fire frequently breaks out. In this study, to clarify the exact cause of the fire, the components and concentration of the materials produced in the process are analysed as well as the problems in the process system, and the protective measure to prevent the fire and the explosion fundamentally is proposed. In this procedure, the preventive measures of fire by removing the combustible materials such as polyurethane and inflammable gases, by removing the ignition sources and by reducing the oxygen concentration to the minimum are proposed along with the protective measures to reduce the damage in the fire. In the crushing procedure where the fire or explosion can break out in diverse ways, the forced ventilation or exhaust system applied to the small partial ventilation facility are installed to reduce the concentration of inflammable gas mixture to lower than the inflammable limit by injecting and exhausting the air forcibly.

• Clean Technology
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• v.29 no.4
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• pp.288-296
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• 2023

Coal is abundantly available compared to other energy sources and is used as a versatile energy resource worldwide. To address the environmental issues stemming from conventional coal utilization, efforts are underway to develop clean coal utilization technologies, with IGCC technology being a notable example. In IGCC plants, coal is subjected to a CMD process where both drying and pulverization are achieved by supplying hot air. However, if the temperature of the supplied hot air is excessively high, it can lead to devolatilization and spontaneous combustion, thereby compromising the stable operation of the CMD process. This study aimed to measure the devolatilization and spontaneous combustion temperatures of different types of bituminous coal, and to explore their correlations with the characteristics of the coals. Six coal types exhibited devolatilization between 350 and 400 ℃, while three coal types showed devolatilization at temperatures exceeding 400 ℃. Spontaneous combustion ℃curred in one coal type below 100 ℃, six coal types between 100 and 150 ℃, and two coal types above 150 ℃. The measured initiation temperatures were compared with the coal characteristics including the oxygen, moisture, Fe₂O₃, and CaO content, the H/C ratio, and the O/C ratio to establish correlations. Regression analysis was used to calculate the regression coefficients and determination coefficients for each ignition temperature. It was found that 52.44% of the FC/VM data significantly influenced the volatile matter ignition temperature, and 59.10% of the Fe₂O₃ data significantly affected the spontaneous combustionignition temperature.