• Journal of the Korean Society of Safety
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• v.24 no.6
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• pp.63-71
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• 2009

In order to improve flame retardancy, the halogen free organic melamine phosphate(M-P) flame retardant was synthesized from melamine and phosphoric acid by the reaction of precipitation. The ignition test was carried out preparing hybrid flame retardant compound($H_bFRC$) consisting of organic M-P and inorganic Mg$(OH)_2$ as a flame retardant in the polyolefin resins. The flame retardancy and mechanical properties of flame retardant aluminum composite panel($H_bFRC$-ACP) were performed to investigate the possibility of the composite material, which was contained M-P, as a inner core for $H_bFRC$-ACP. For this study, the results of ignition test indicate that a char formation and drip suppressing effect, and combustion time reduced as the content of M-P increased. The limited oxygen index(LOI) values were measured 17.4vol% and 31.5vol% for LDPE only and $H_bFRC$-3(M-P content: 15wt%), respectively. And it was verified that the $H_bFRC$-3 was needed more oxygen quantity with the increase of M-P content when it combustion. Also, the results from thermogravimetric analysis were observed endothermic peak at $350^{\circ}C$ and $550^{\circ}C$, it was confirmed predominant thermal stability though the wide temperature range by the mixture of M-P and Mg$(OH)_2$. The LDPE-ACP (using only LDPE as a inner core), $35.13kW/m^2$ of heat release rate(HRR) and 13.43MJ/m2 of total heat release(THR) were measured while the $H_bFRC$-ACP, $10.44kW/m^2$ of HRR and 1.84MJ/m2 of THR were measured by results of cone calorimeter test. In case of $H_bFRC$-ACP, the average gas emission amount of CO and $CO_2$ could be decreased down to 25% and 20%, respectively, in comparison with LDPE-ACP. The mechanical properties such as tensile strength, bending strength and adhesion strength of $H_bFRC$-ACP were revealed slightly high values $54N/mm^2$, $152N/mm^2$ and 120N/25mm, respectively, compared with LDPE-ACP. It was confirmed that flame retardancy was improved with the synergy effect because of char formation by M-P and hydrolysis by Mg$(OH)_2$. The result of this study suggest that $H_bFRC$ can be applied for an adequate halogen free flame retardant composite material as a inner core for ACP.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.5
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• pp.518-524
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• 2013

In this study, we conducted a study on characteristics of exhaust gas emissions from boiler when water-bunker oil mixed by homogenizer was burned in boiler. The results showed that NOx concentration and CO concentration of the homogenized bunker oil was decreased by 19% and 54% compared to pure bunker oil pretreatment was not being performed. And, in the case of water-bunker A oil, the NOx concentration was decreased with increasing water mixing ratio in bunker A oil. In particular, the NOx concentration in exhaust gas of 20 %water-80 %bunker A oil decrease by 45 % compared with pure bunker-A. However, the CO concentration in exhaust gas of 20 %water-80 %bunker A oil shows irregular changes. This means that the mixing of water more than a certain amount can cause a decrease in combustion performance. From this result, it can be found that critical mixing ratio of water in bunker A oil for normal combustion is 15% in this study. Deposition amount of soot that is collected in the vicinity of the chimney was decreased with increasing water mixing ratio.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.1
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• pp.97-104
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• 2015

This study is a part of the high pressure injection system development on the Turbo GDI engine in order to reduce smoke emission in case of using the low volatile(high DI) fuel which is used as normal gasoline fuel in the US market. Firstly, theoretical approach was done regarding gasoline fuel property, performance, definition of particle matters and its creation as well as problems of the high DI fuel. In this experimental study, 2L Turbo GDI engine was selected and optimized system parameter was inspected by changing fuel, fuel injection mode (single/multiple), fuel pressure, distance between injector tip and combustion chamber, start of injection, intake valve timing in engine dyno at all engine speed range with full load. In case of normal gasoline fuel, opacity was contained within 2% in all conditions. On the other hands, in case of low volatile fuel (high DI fuel), it was confirmed that the opacity was rapidly increased above 5,000 rpm at 14.5 ~ 20 MPa of fuel pressure and there were almost no differences on the opacity(smoke) between 17 MPa and 20 MPa fuel pressure. According to the SOI retard, smoke decrease tendency was observed but intake valve close timing change has almost no impact on the smoke level in this area. Consequently, smoke decrease was observed and 16% at 6000rpm respectively with injector washer ring installed. By removing injector washer to make injector tip closer to the combustion chamber, smoke decrease was observed by 46% at 5,500 rpm, 42% at 6,000 rpm. It is assumed that the fuel injection interaction with cylinder head, piston head, intake and exhaust valve is reduced so that impingement is reduced in local area.

• Membrane Journal
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• v.30 no.2
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• pp.97-110
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• 2020

CO₂ capture and storage (CCS) is one of the promising technologies that can mitigate ever-growing emission of anthropogenic carbon dioxide and resultant climate change. Among them, chemical looping combustion (CLC) and calcium looping (CaL) are getting increasing attention recently as the prospective alternatives to the existing amine scrubbing. Both methods use metal oxides in the process and consist of cyclic reactions. Yet, due to their cyclic nature, they both need to resolve sintering-induced cyclic stability deterioration. Moreover, the structure of the metal oxides needs to be optimized to enhance the overall performance of CO₂ capture and storage. Deposition of thin film coating on the metal oxide is another way to get rid of wear and tear during the sintering process. Chemical vapor deposition or atomic layer deposition are the well-known, established methods to form thin film membranes, which will be discussed in this review. Various effective recent developments on structural modification of metal oxide and incorporation of stabilizers for cyclic stability are also discussed.

• Clean Technology
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• v.24 no.4
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• pp.323-331
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• 2018

The results of an experimental investigation on the co-firing characteristics and slagging behavior of dried and hydrothermal carbonization sewage sludge, sub-bituminous coal, and wood pellet in a fluidized bed were presented. Combustion tests were conducted in a lab-scale bubbling fluidized bed system at the uniform fuel-air equivalence ratio, air flow rate, and initial bed temperature to measure bed temperature distribution and combustion gas composition. 4 different fuel blending cases were prepared by mixing sewage sludge fuels with coal and wood pellet with the ratio of 50 : 50 by the heating value. $NO_x$ was mostly NO than $NO_2$ and measured in the range of 400 to 600 ppm in all cases. $SO_2$ was considered to be affected mostly by the sulfur content of the sewage sludge fuels. The cases of hydrothermal carbonization sewage sludge mixture showed slightly less $SO_2$ emission but higher fuel-N conversion than the dried sewage sludge mixing cases. The result of fly ash composition analysis implied that the sewage sludge fuels would increase the possibility of slagging/fouling considering the contents of alkali species, such as Na, K, P. Between the two different sewage sludge fuels, dried sewage sludge fuel was expected to have the more severe impact on slagging/fouling behavior than hydrothermal carbonization sewage sludge fuel.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.626-631
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• 2019

The policy-making and technological development for the supply expansion of eco-friendly automobiles has been continuing, but the internal combustion engines still accounts for about 95%. Also, in order to meet the stricter emission regulations of internal combustion engines based on fossil fuels, the proportion of after-treatments for vehicles and (ocean going) vessels is gradually increasing. This study is a basic study for the post-Euro-VI exhaust response of CNG buses, and it is to investigate the basic characteristics according to Pd substitution transition metal effect, catalyst volume effect and space velocity. A catalysts was prepared and tested using a model gas reactor. The NGOC catalyst with 3Pd exhibited the highest catalytic activity with 22% at $300^{\circ}C$, 48% at $350^{\circ}C$ and about 75% at $500^{\circ}C$. 3Co NGOC containing 3wt% of transition metal was excellent in oxidation ability, and it was small in size of 2nm, and the degree of catalyst dispersion was improved and de-NO/CO conversion was high. The volume of the NGOC-LNT-SCR catalyst system was optimal in the combination of 1.5+0.5+0.5 with a total score of 165, considering $de-CH_4/NOx$ performance and catalyst cost. For SV $14,000h^{-1}$, the $CH_4$ reduction performance was the highest at about 20%, while the SV $56,000h^{-1}$ was the lowest at about 5%. If the space velocity is small, the flow velocity decreases and the time remaining in the catalyst volume become long, so that the harmful gas was reduced.

• Atmosphere
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• v.31 no.5
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• pp.625-635
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• 2021

South Korea established the 2050 Carbon Neutral Plan in response to the climate crisis, and to achieve this policy, it is very important to monitor domestic carbon emissions and atmospheric carbon concentration. Both CO₂ and CO are emitted from fossil fuel combustion processes, but the relative ratios depend on the combustion efficiency and the strength of local emission regulations. In this study, the relationship between CO₂ and CO was analyzed using ground observation data for the period of 2018~2020 at Anmyeon-do site and the CO/CO₂ ratio according to regional origin during high CO₂ cases was investigated based on the footprint simulated from Stochastic Time-Inverted Lagrangian Transport (STILT) model. CO₂ and CO showed a positive correlation with correlation coefficient of 0.66 (p < 0.01), and averaged footprints during high CO₂ cases confirmed that air particles mainly originated from eastern and north-eastern China, and inland of Korean Peninsula. In addition, it was revealed that among the cases of high CO₂ concentration, when the CO/CO₂ ratio is high, the industrial area of eastern China is greatly affected, and when the ratio is low, the contribution of the domestic region is relatively high. The ratio of CO₂ and CO in this study is significant in that it can be used as a useful factor in determining the possibility of domestic and foreign origins of climate pollutants.

• Journal of the Korean Institute of Gas
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• v.28 no.2
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• pp.1-6
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• 2024

An easy approach to replacing older diesel engines is to replace them with gas engines using fuels such as CNG or LPG. However, fuels such as LPG have not been applied to large gas engines in many cases, so it is not easy to predict the performance of gas engines based on CNG fuel. Accordingly, in this study, we applied LPG fuel to a CNG-based large gas engine and examined the performance and emission characteristics. In particular, the results were confirmed through tests to see how effective EGR, which is widely used for NOx reduction, is applied. As a result, in the case of LPG, even though the operating conditions were secured to a level that excludes serious knocking, mild knocking at high loads was still found to be more frequent than CNG. However, it was possible to secure an output level similar to CNG in the high-speed range. Efficiency was higher due to a faster combustion speed than CNG, and it was confirmed that it was possible to simultaneously reduce NOx and the frequency of mild knocking through the application of EGR.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.790-795
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• 1997

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofuransfurans are the archetype of toxic chemicals. So it has absorbed public attention. The majors primary sources of PCDDS and PCDFs are chemical, thermal and photochemical reactions. Municipal solid waste incinerator facilities has been reported as the major contributors of dioxins to the environment. In this paper, Dioxins and furans were examined emission gas and fly ash produced during combustion in municipal solid waste incinerator. More effective method for sampling, extraction was described. The sample was extracted using a soxhlet method and purified using silicagel, alumina and carbon fibre HPLC to remove interfering compound. The extract was then analyzed by HRGC/HRMS. The result of this study showed recovery standard was good and the data resembled those of thermal processes. Total dioxins and furans were $1076.20pg/Nm^3$ and $1452.34pg/Nm^3$ respectively. The amount of highly chlorinated compound was more than that of lowly chlorinated compound. The 2,3,7,8-substituted TCDD was Just 0.34% of the total dioxins/furans amount.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.3
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• pp.54-67
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• 2014

This study was performed to estimate Greenhouse gases(GHGs) emissions from biomass burning at large forest fire(Ulju, Pohang and Bonghwa) in 2013. The extended methodology to estimate GHGs adopted the IPCC(Intergovermental Panel on Climate Change) Guidelines(2006) equation. For classifying fire damaged area and analyzing burn severity of total three large-fire area damaged, this study used post-fire imagery from Rapideye imagery to compute the Maximum Likelihood Classifiction (MLC). The result of accuracy assessment on burn severity from imagery showed that average overall accuracy was 75.93% and Kapp coefficient was 0.67 Finally, GHGs emissions from biomass burning in the three large-fire area 2013 were estimated as follows: Ulju $CO_2$ 63,260, CO 5.207, $CH_4$ 360, $N_2O$ 28.0 and $NO_x$ $4.4g/kg^{-1}{\cdot}ha^{-1}$, Pohang $CO_2$ 28,675, CO 2.359, $CH_4$ 163, $N_2O$ 12.7 and $NO_x$ $1.9g/kg^{-1}{\cdot}ha^{-1}$ and Bonghwa $CO_2$ 53,086, CO 1,655, $CH_4$ 114, $N_2O$ 23.5 and $NO_x$ $3.6g/kg^{-1}{\cdot}ha^{-1}$.