• Journal of the Korean Institute of Gas
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• v.4 no.2 s.10
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• pp.1-6
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• 2000

In this experiment, we made the plasma reactor which adhere needle electrode in order to treat safely an NOx which was included in the gas. Also we experimently investigated characteristics of equipment and inspected efficiency. As a reaction gas, by using mixture gas of $NO/N_2$ and $N_2/O_2$, we setted up initial NO concentration and gas flow rate was set at 2 ${\iota}$/min. As a reaction characteristics of NOx, when discharge input power was high, NO concentration decreased and when the oxygen concentration increased, the NO decomposition was easy and decomposition energy efficiency was high. Also in case that NO concentration increased, NO decomposition energy efficiency was high but decomposition rate was low. The characteristics of ozone, when discharge input power was high, ozone increased and when $NO/N_2$ concentration increased, the ozone decreased.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.5
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• pp.105-111
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• 2007

In this study, we investigated the conversion performance of de-NOx catalyst for lean-burn natural gas engine. As a de-NOx catalyst, NOx storage reduction catalyst was composed of Pt, Pd and Rh with washcoat including Ba and Ni, Ru-ZSM-5. Ni, Ru-ZSM-5, which was regarded as a NOx direct decomposition catalyst, was made up of ion exchanged ZSM-5 by 5wt.% Ni or Ru. The performance of de-NOx catalyst was evaluated by NOx storage capacity and catalytic reduction in air/fuel, $\lambda=1.6$. The catalytic reaction was also observed when the added fuel was supplied to fuel rich atmosphere by fuel spike period of 5 seconds. The NOx conversion of the catalysts with Ni-ZSM-5 or Ru-ZSM-5 was mainly caused by the effect of NOx adsorption of Ba rather than the catalytic reduction of Ni, Ru-ZSM-5. Ni, Ru-ZSM-5 catalysts can not use for the NSR catalyst because they have quick process in thermal deactivation.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1999.06a
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• pp.217-222
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• 1999

비열플라스마를 형성하는 방법은 전자 beam조사식과 전기방전법이 있다. 이 두방법의 공통점은 고에너지의 전자를 생성하여 플라스마를 발생시켜 가스분자의 전자충돌과 이온화에 의해 free radical반응에 의하여 가스분자를 분해시키는 것이다. (중략)

• Korean Journal of Materials Research
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• v.32 no.11
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• pp.496-507
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• 2022

For the selective catalytic reduction of NOx with ammonia (NH₃-SCR), a V₂O₅WO₃/TiO₂ (VW/nTi) catalyst was prepared using V₂O₅ and WO₃ on a nanodispersed TiO₂ (nTi) support by simple impregnation process. The nTi support was dispersed for 0~3 hrs under controlled bead-milling in ethanol. The average particle size (D₅₀) of nTi was reduced from 582 nm to 93 nm depending on the milling time. The NOx activity of these catalysts with maximum temperature shift was influenced by the dispersion of the TiO₂. For the V_0.5W₂/nTi-0h catalyst, prepared with 582 nm nTi-0h before milling, the decomposition temperature with over 94 % NOx conversion had a narrow temperature window, within the range of 365-391 ℃. Similarly, the V_0.5W₂/nTi-2h catalyst, prepared with 107 nm nTi-2h bead-milled for 2hrs, showed a broad temperature window in the range of 358~450 ℃. However, the V_0.5W₂/Ti catalyst (D₅₀ = 2.4 ㎛, aqueous, without milling) was observed at 325-385 ℃. Our results could pave the way for the production of effective NOx decomposition catalysts with a higher temperature range. This approach is also better at facilitating the dispersion on the support material. NH₃-TPD, H₂-TPR, FT-IR, and XPS were used to investigate the role of nTi in the DeNOx catalyst.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.169-172
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• 1999

In this experimental study we Proposed the double dielectric barrier discharge (DDBD) reactor to produce as high an electric field as possible. The experiment are conducted for applied voltage from 15 to 20[tV], flow gas rage at 2[1/min] and pulse rate at 120[pulses/s] and 240[pulses/s]. SPD connection of DDBD which combine the surface discharge with the silence discharge was most effective to reduce the NOx. In the decomposition efficiency per watt, the low pulse rate gave hotter efficiency than that of the high pulse rate. However in DeNOx rate, the high pulse rate gave better performance than that of the low pulse rate. NOx removal rate increased with increasing the applied voltage in all reactors.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.4
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• pp.32-37
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• 1999

The superposing effect of SPCP(Surfoce Induced Plasma Chemical Process) and corona discharge has been studied for rerroval of NOx from industrial flue gases. NOx rermval rates by SPCP, corona discharge and superposing discharge were monitored and compared. Parameters were the concentration and the flow rate of gas, frequency and the type of discharge. Experirrental results showed that NOx removal rate by sUIffPOSing discharge was 10-15[%] higher than that by the other two modes. The higher NOx. rermval rate was observed with the lower frequency of upper electrode in the combined reactor and with the higher frequency of lower electrode. 'The maximum obtainable NOx. rerroval rate by SPCP (18 [W]) and corona discharge (8.5 [W]) was 80[%] and 10[%], respectively. With the combination of the two modes, however, 90[%] of NOx removal rate was observed with the discharge power of 14 [W].14 [W].

• Journal of Powder Materials
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• v.8 no.3
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• pp.201-206
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• 2001

$>LaMnO_3$$(La, Sr)MO_3$, and $(La, Sr)MO_3/YSZ$ gel films were deposited by spin-coating technique on scandium-doped zirconia (YSZ) substrate using the precursor solution prepared from $La(O-i-C_3H_7)_3$, $Co(CH_3COO)_2$or $Mn(O-i-C_3H_7)_2$,2-methoxyethanol, and polyethylene glycol. By heat-treating the gel films, the electrochemical cells, $(La, Sr)MnO_3{\mid}ScSZ{\mid}Pt$ were fabricated. The effect of polyethylene glycol on the microstructure evolution of $$LaCoO_3and $LaMnO_3$thin films was investigated, and NOx decomposition characteristics of the electrochemical cells were investigated at $500^{\circ}C$ to $600^{\circ}C$. By applying a direct current to the $(La, Sr)MnO_3{\mid}ScSZ{\mid}Pt$ electrochemical cell, good NOx conversion rate could be obtained relatively at low current value even if excess oxygen is included in the reaction gas mixture.

• Journal of ILASS-Korea
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• v.27 no.1
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• pp.11-17
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• 2022

In upcoming Post Stage-V and Tier 5 regulations of construction machineries, nitrogen oxide (NOx) emissions are strictly limited in cold start conditions. In response to this, a method of improving NOx conversion efficiency has been applied by installing an electric heating catalyst (EHC) in front of conventional urea-SCR systems so that the evaporation and thermal decomposition of urea-water solution can be promoted in cold start conditions. In this strategy, the evaporation and thermal decomposition of urea-water solution and corresponding NOx conversion efficiency are governed by temperature conditions inside the EHC. Therefore, characterizing the temperature distribution in the EHC under various operating conditions is crucial for the optimized operation and control of the EHC in Urea-SCR systems. In this study, a 1-D modeling analysis was performed to predict the heater surface temperature distribution in EHC under various operating conditions. The reliability of prediction results was verified by comparing them with measurement results obtained using an infrared (IR) camera. Based on 1-D analysis results, the effects of various EHC operation parameters on the heater surface temperature distribution were analyzed and discussed.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2001.05a
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• pp.147-150
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• 2001

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.165-172
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• 2008

Urea-SCR, the selective catalytic reduction using urea as reducing agent, has been investigated for about 10 years in detail and today is a well established technique for deNOx of stationary diesel engines. In the case of the SCR-catalyst a non-uniform velocity and $NH_3$ profile will cause an inhomogeneous conversion of the reducing agent $NH_3$, resulting in a local breakthrough of $NH_3$ or increasing NOx emissions. Therefore, this work investigates the effect of flow and $NH_3$ non-uniformities on the deNOx performance and $NH_3$ slip in a Urea-SCR exhaust system. From the results of this study, it is found that flow and $NH_3$ distribution within SCR monolith is strongly related with deNOx performance of SCR catalyst. It is also found that multi-hole injector shows better $NH_3$ uniformity at the face of SCR monolith face than one hole injector.