• Journal of Industrial Technology
• /
• v.39 no.1
• /
• pp.1-5
• /
• 2019

In this study, we examined the effect of NO addition on the ozone-induced soot oxidation activity of $LaMnO_3$ perovskite catalysts. The addition of 10~20% NO ($NO_2$) with respect to the concentration of ozone effectively enhanced the rate of ozone-induced soot oxidation rate over $LaMnO_3$. However, the excessive addition of NO ($NO_2$) was detrimental to ozone-induced soot oxidation activity. It is supposed nitrogen oxides would adsorb on the catalyst and then react with carbon-oxygen species developed on soot surface, but an excessive addition of nitrogen oxide would inhibit the formation of carbon-oxygen species, which is a key intermediate in the reaction, and consequently suppress the oxidation rate of soot.

• Journal of Biosystems Engineering
• /
• v.24 no.6
• /
• pp.465-472
• /
• 1999

To remove nitrogen oxides(NOx) in exhaust gas of diesel engine, three-way catalytic process with plasma discharger has great possibilities. Characteristics of NOx removal depends on NO conversion to NO$_2$and/or HNO$_3$due to high activation energies for NO oxidation and reduction. NOx removal efficiency by using three-way catalytic with plasma discharger indicated about 50% at 40watt power consumption condition.

• Journal of Advanced Marine Engineering and Technology
• /
• v.23 no.6
• /
• pp.755-760
• /
• 1999

To remove nitrogen oxides(NOx) in exhaust gas of diesel engine three-way catalytic process with plasma discharger has great possibilities. Characteristics of NOx removal depends on NO conver-sion to $NO_2$ and /or $HNO_3$ due to high activation energies for NO oxidation and reduction, NOx removal efficiency by using three-way catalytic with plasma discharger indicated about 50% at 40watt power consumption condition.

• 한국연소학회:학술대회논문집
• /
• 2012.04a
• /
• pp.69-74
• /
• 2012

Looming global environmental pollution problems around the world movement to minimize the environmental pollution is actively taking place. International Maritime Organization (IMO) a significant portion of the marine pollution by exhaust gases emitted from vessel considered, and accordingly developed around the ship and ship-related environmental regulations, emission standards are going to strengthen gradually, the development of environmentally friendly vessels and equipment is proceeding actively.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.7 no.8
• /
• pp.83-90
• /
• 1999

To remove nitrogen oxides(NOx) in exhaust gas of diesel engine, three-way catalytic process with plasma discharger has great possbilities. Characteristics of NOx removal depends on NO conversion to $NO_2$ and/or $HNO_3$ due to high activation energies for NO oxidationand reduction. NOx removal efficiency by using three-way catalytic with plasma dischager indicated about 50% at 40 watt power consumption condition.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.31A no.6
• /
• pp.117-127
• /
• 1994

In this paper, electrical and reliability properties of N$_2$O oxides, grown at the temperature of 95$0^{\circ}C$ and 100$0^{\circ}C$ to 74$\AA$, and 82$\AA$. respectively, using NS12TO gas in a conventional furnace, have been compared with those of pure oxide grown at the temperature of 850 to 84$\AA$ using O$_2$ gas. Initial IS1gT-VS1gT characteristics of N$_2$O oxides were similar to those of pure oxide, and reliability properties of N$_2$O oxides, such as charge trapping, interface state density and leakage current at low electric field under F-N stress, were improved much better than those of pure oxide. But, with increasing capacitor area. TDDB characteristics of N$_2$O oxides were more degraded than those of pure oxide and this degradation of TDDB characteristics was more severe in 100$0^{\circ}C$ N$_2$Ooxide than in 95$0^{\circ}C$ N$_2$O oxide. The improvement of reliability properties excluding TDDB in N$_2$Ooxides was attributed to the hardness of the interface improved by nitrogen pile-up at the interface of Si/SiO$_2$, but on the other hand, the degradation of TDDB characteristics in N$_2$O oxides was obsered due to the increase of local thinning spots caused by excessive nitrogen at interface during the growth of N$_2$O oxides.

• Applied Chemistry for Engineering
• /
• v.21 no.3
• /
• pp.243-251
• /
• 2010

Nitrogen oxides (NOx) in combustion flue gas are currently mitigated by chemical processes such as catalytic reduction, absorption and adsorption. However, development of environmentally sustainable biological processes is necessary in the near future. In this paper, the up-to-dated R&D trend of biological methodologies regarding NOx removal was reviewed, and their advantages and disadvantages were discussed. The principles and applications of bacterial system including nitrification and denitrification and photosynthetic microalgae system were compared. In order to enhance biological treatment rate and performance, the insoluble nitric oxide (NO) should be first absorbed using a proper solubilization agent, and then microbial degradation or fixation is to be followed. The use of microalgal system has a good prospect because it can fix $CO_2$ and NOx simultaneously and requires no additional carbon for energy source.

• Journal of ILASS-Korea
• /
• v.29 no.2
• /
• pp.60-67
• /
• 2024

This study compared exhaust gas recirculation (EGR) and excess air strategies for improving thermal efficiency and emissions of hydrogen combustion engines at low-load operation. The experimental investigation was conducted in a single-cylinder, heavy-duty engine under throttling and wide-open throttle (WOT) conditions. Although both EGR and excess air strategies reduced peak heat release rates and increased combustion durations, the net indicated thermal efficiencies were improved by reducing the pumping losses. Under the constraint of similar nitrogen oxides emissions, the EGR strategy had higher net indicated thermal efficiencies compared to the excess air strategy in throttling operation. However, the difference between their thermal efficiencies was reduced under WOT condition. The trend of reducing nitrogen oxides emissions according to the two strategies was similar.

• Journal of the Korean Institute of Gas
• /
• v.19 no.5
• /
• pp.20-28
• /
• 2015

This work investigated the size and shape effect of ${\gamma}$-alumina-supported metal oxides on the hydrocarbon selective catalytic reduction of nitrogen oxides. Several metal oxides including Ag, Cu and Ru were used as the catalysts, and n-heptane as the reducing agent. For the Ag/${\gamma}$-alumina catalyst, the $NO_x$ reduction efficiency in the range of $250{\sim}400^{\circ}C$ increased as the size of Ag decreased (20 nm>50 nm>80 nm). The shape effect of metal oxides on the $NO_x$ reduction was examined with spherical- and wire-shape nanoparticles. Under identical condition, higher catalytic activity for $NO_x$ reduction was observed with Ag and Cu wires than with the spheres, while spherical- and wire-shape Ru exhibited similar $NO_x$ reduction efficiency to each other. Among the metal oxides examined, the best catalytic activity for $NO_x$ reduction was obtained with Ag wire, showing almost complete $NO_x$ removal at a temperature of $300^{\circ}C$. For Cu and Ru catalysts, considerable amount of NO was oxidized to $NO_2$, rather than reduced to $N_2$, leading to lower $NO_x$ reduction efficiency.

• Journal of Korean Society for Atmospheric Environment
• /
• v.19 no.4
• /
• pp.427-436
• /
• 2003

This study is to establish a waste bed combustion model that can be available to assist the design of incinerators for efficient operation control of municipal waste incinerators. An unsteady one -dimensional bed combustion modeling was developed which incorporates the various sub-process models and solves the governing equations for both gases and solids in the waste bed combustion phenomena. The combustion characteristics and the properties of the combustion gas released from the bed were investigated by using a developed model. Besides, a sub-model which predicts the formation and destruction of nitrogen oxides in the waste bed was also developed as a post-processor for the waste combustion model. It is found that the reduction rate of nitrogen oxides is enhanced in the char layer.