• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3383-3388
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• 2014

An experimental study was performed to compare the characteristics of the combustion pressure and exhaust emissions in the case of using pure diesel when the EGR rate was changed in a CRDI 4-cylinder diesel engine with those using biodiesel blended and pure diesel fuel. In this study, the EGR rate variation were conducted at an engine speed of 2000rpm with fuel with a biodiesel blended rate of 20%. The combustion pressure of the biodiesel blended rate 20% and pure diesel fuels decreased with increasing EGR rate. The IMEP of biodiesel was higher than that of ULSD (Ultra low sulfur diesel). The emission results showed that the NOx emission of biodiesel blended fuel with increasing EGR rate was higher than that of ULSD. In addition, the NOx emission of biodiesel blended and diesel fuel decreased with increasing EGR rate. The CO and soot, $CO_2$ emissions increased with increasing EGR rate, and the CO and soot emissions from the biodiesel blended fuel were lower than that of ULSD but the $CO_2$ emissions were higher.

• Journal of the Korean Society of Combustion
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• v.12 no.3
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• pp.1-7
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• 2007

A combined hydrogen generator of plasma and catalytic reformer was developed, and was applied to stabilize unstable flame of 200,000 Kcal/hr LPG combustor. The role of the plasma reformer was to generate hydrogen in a short period and to heat-up the catalytic reformer during the start-up time. After the start-up period, the catalytic reformer generates hydrogen through steam reforming with oxygen (SRO) reactions. The maximum capacity of the hydrogen generator was enough 100 lpm to stabilize the flame of the present combustor. In order to reduce NOx and CO emissions simultaneously, 1) FGR (Flue Gas Recirculation) technique has been adopted and 2) the hydrogen was added into the fuel supplied to the combustor. Test results showed that the addition of 25% hydrogen and 30% FGR rate lead to simultaneous decrease of CO and NOx emissions. The technique developed in the present study showed good potential to replace $NH_3$ SCR technique, especially in the small-scale combustor applications.

• 한국연소학회:학술대회논문집
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• 2007.05a
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• pp.187-190
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• 2007

A combined hydrogen generator of plasma and catalytic reformers has been developed, and has been applied to stabilize unstable flame of 200,000 Kcal/hr LPG combustor. The role of the plasma reformer is to generate hydrogen in a short period and to heat-up the catalytic reformer during the start-up time. After the start-up period, the catalytic reformer generates hydrogen through steam reforming with oxygen (SRO) reactions. The maximum capacity of the hydrogen generator is 100 lpm that is sufficient to be used to stabilize the flame of the present combustor. In order to reduce NOx and CO emissions simultaneously, 1) FGR (Flue Gas Recirculation) technique has been adopted and 2) the hydrogen has been added into the fuel supplied to the combustor. Test results shows that 25 % addition of hydrogen and 30 % FGR rate lead to simultaneous decrease of CO and NOx emissions. The technique proposed in the present study shows good potential to replace $NH_3$ SCR technique, especially in the case of small-scale combustor applications.

• Journal of ILASS-Korea
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• v.21 no.2
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• pp.71-77
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• 2016

Air pollutants nitrogen oxides are inevitably generated in the combustion reaction. Its amount trend is steadily increasing because the rapid modern industrialization and population growth. For this reason, NOx is controlled to reducing the harmful components in the exhaust gas. So Marine Environment Protection Committee (MEPC) take effect 'Tier I', 'Tier II' of air pollution regulation in 2005 and 2011 respectively. According to NOx emissions are strictly regulated management of the vessel through them. In addition, since 2016 the regulation enter into force in the next step 'Tier III' was confirmed by MEPC 66th committee. It's 80% enhanced emissions limits than the 'Tier I' Alternatively these emission regulation, research is actively being carried out about exhaust gas after-treatment methods through the vessel application of Selective Catalytic Reduction(SCR). Therefore depending on the basic specification of cell density according to the Area velocity, Space velocity, Linear velocity is studied the effects of NOx removal efficiency

• Journal of ILASS-Korea
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• v.23 no.4
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• pp.234-243
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• 2018

Since September 2017, a small diesel vehicle certification test mode has been enhanced from NEDC to WLTC. The main reason for the change of the certification test mode is that the certification test mode of the emission control standard of the diesel vehicle does not sufficiently reflect various driving patterns of the actual roads. Several automakers have developed after-treatment systems such as LNT, SCR, and DPF to meet enhanced emissions regulations. In this study, four small diesel cars were selected for sale in Korea, and the exhaust gas measurement test was performed in the WLTC mode, which reflects the driving characteristics of the actual roads. As a result of test, LNT vehicle exceeded Euro 6 NOx regulation and SCR vehicle satisfied Euro 6 NOx regulation. In addition, both LNT and SCR systems showed high NOX emission characteristics due to speed, RPA and Vxa. For the PN, all test vehicles were fitted with a DPF and met the Euro 6 PN regulations, with similar PN emissions results in LNT and SCR system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.6
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• pp.577-583
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• 2011

To meet the requirements of the Tier 4 interim regulations for off-road vehicles, emissions of particulate matter (PM) and nitrogen oxides (NOx) must be reduced by 95% and 30%, respectively, compared to current regulations. In this research, both the DPF and HPL EGR systems were investigated, with the aim of decreasing the PM and NOx emissions of a 56-kW off-road vehicle. The results of the experiments show that the DOC-DPF system is very useful for reducing PM emissions. It is also found that the back pressure is acceptable, and the rate of power loss is less than 5%. By applying the HPL EGR system to the diesel engine, the NOx emissions under low- and middle-load conditions are reduced effectively because of the high differential pressure between the turbocharger inlet and the intake manifold. The NOx emissions can be decreased by increasing the EGR rate, but total hydrocarbon (THC) emission increases because of the increased fuel consumption needed to compensate for the power loss caused by EGR and DPF.

• Journal of the Korean earth science society
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• v.42 no.2
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• pp.149-163
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• 2021

In this study, the changes in ozone (O3) concentrations due to the removal of power plant emissions were analyzed using a community multi-scale air quality (CMAQ) model. Two different CMAQ model simulations, one considering the emissions from the Hadong power plant and one without considering the emissions, were conducted to investigate the effect of the emissions on the changes in the O3 concentrations in the surrounding areas. Subsequently, the CMAQ simulations exhibited an increase in the O3 concentration (25.24%) despite a decrease in the NOx (-18.87%) and volatile organic carbon (VOC, -11.27%) concentrations, which are major O3 precursors. The changes in the NO and O3 concentrations due to the removal of power plant emissions presented a strong negative correlation (r= -0.72). This indicated that the increase in the O3 concentration was mainly attributed to the significantly decreased NO concentration, thus, mitigating the O3 titration reaction (NO+O3→NO2+O2). Additionally, due to the VOC-limited (i.e., NOx-saturated) conditions in the study region, NO affected the O3 concentration, indicating that the O3 concentrations in a particular region are not only proportional to the increase or decrease in emissions. Therefore, an in-depth understanding of the chemical O3 production and loss in a particular region is necessary to accurately evaluate the effect of emission control on the changes in the O3 concentration.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.7
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• pp.905-917
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• 2021

Atmospheric pollutant emissions, mainly exhaust gas emissions from vessels, and the resultant social costs of pollution in the Korean harbor cities of Incheon, Mokpo, Gwangyang, Busan and Ulsan, are examined in this study, and the need for an emissions reduction plan is highlighted. Busan had several vessels entering its port, while Mokpo had few vessels, yet the vessels emission contribution was high in both the cities. Ulsan had world-class heavy-chemical industries, Gwangyang had steel mills and Incheon had a manufacturing industry and more vessels entering its port than Mokpo, yet the emission contribution was low in these cities. By calculating exhaust gas emissions from the vessels, it was found that CO₂ was the highest, followed by NOx and SOx. By vessel type, Busan, Ulsan, and Incheon had more oil tank vessels, Gwangyang had more cargo vessels, and Mokpo had more ferries. As a result of social cost, Busan paid the highest, while the highest emission was PM. The use of low-sulfur oil can directly reduce PM and, SOx emissions and indirectly reduce NOx emissions. However, in order to reduce high CO₂ emissions, only low-sulfur oil will not help. Therefore, the study suggested the need for reduction plan that use of fossil fuels, by using alternative maritime power (AMP).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.1
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• pp.51-57
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• 2013

This study aims to experimentally investigate the combustion characteristics of a lean premixed swirl-stabilized burner with dual-stage fuel injection arrays. The results show that a variation in the fuel distribution to fuel stages 1 (upstream) and 2 (downstream) produces a noticeable change in the NOx and CO emissions. Reducing the confined ratio, defined as the ratio of the nozzle exit diameter to the liner diameter, may reduce NOx and CO emissions owing to reduced combustion loading and longer residence time, respectively. A nozzle exit velocity of 30 m/s shows the optimum characteristics in terms of NOx and CO emissions and flame stability: increasing or decreasing the nozzle exit velocity leads to a degradation in emissions or flame stability, respectively.

• Particle and aerosol research
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• v.15 no.4
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• pp.159-171
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• 2019

The cap-and-trade system against the air pollutants in the Seoul Metropolitan Area (SMA), Korea has been implemented since 2008 and will be implemented other areas in Korea on 2020. In this study, to identify the outcome and effectiveness of the cap-and-trade system in the SMA, (1) the rate of change for NOx and SOx emissions, (2) differences between the real emission and allocated amount, and (3) the status of trading are reviewed. It was found that the NOx and SOx emissions from the sources under the cap-and-trade system decreased in the SMA but the reduction was mainly due to the reduction of fuel usage not related to the system. It was found that the average percentage of annual emission in the SMA to the allocated amount between 2008 and 2018 was 66.9% for NOx and 69.3% for SOx, respectively. It suggests that there was over allocation of the emission amounts. The average trading prices in the SMA were 0.193 $/kg for NOx and 0.128 $/kg for SOx, far lower than those in RECLAIM, 131.942 $/kg and 81.677 $/kg, respectively. It was suggested that (1) the cap system for NOx and SOx emissions should be implemented only for the area with high emission ratio from large point sources, (2) the trade system is not suitable for the effective implementation of the cap system, and (3) Korean government should not allow over allocation in order to ensure sound market function without delaying the introduction of technology.