• Clean Technology
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• v.27 no.4
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• pp.341-349
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• 2021

In combustion facilities, the nitrogen and sulfur in fossil fuels react with oxygen to generate air pollutants such as nitrogen oxides (NO_X) and sulfur oxides (SO_X), which are harmful to the human body and cause environmental pollution. There are regulations worldwide to reduce NO_X and SO_X, and various technologies are being applied to meet these regulations. There are commercialized methods to reduce NO_X and SO_X emissions such as selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR) and wet flue gas desulfurization (WFGD), but due to the disadvantages of these methods, many studies have been conducted to simultaneously remove NO_X and SO_X. However, even in the NO_X and SO_X simultaneous removal methods, there are problems with wastewater generation due to oxidants and absorbents, costs incurred due to the use of catalysts and electrolysis to activate specific oxidants, and the harmfulness of gas oxidants themselves. Therefore, in this research, microbubbles generated in a high-pressure disperser and reducing agents were used to reduce costs and facilitate wastewater treatment in order to compensate for the shortcomings of the NO_X, SO_X simultaneous treatment method. It was confirmed through image processing and ESR (electron spin resonance) analysis that the disperser generates real microbubbles. NO_X and SO_X removal tests according to temperature were also conducted using only microbubbles. In addition, the removal efficiencies of NO_X and SO_X are about 75% and 99% using a reducing agent and microbubbles to reduce wastewater. When a small amount of oxidizing agent was added to this microbubble system, both NO_X and SO_X removal rates achieved 99% or more. Based on these findings, it is expected that this suggested method will contribute to solving the cost and environmental problems associated with the wet oxidation removal method.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.10
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• pp.1442-1449
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• 2003

We investigated the amount of the toxic gases emitted from the Electrostatic Precipitators(ESPs), which are currently used as the indoor air cleaners. The existing wire-to-plate(WTP) and neddle-to-plate(NTP) types of ESP designs are considered as the experimental corona dischargers. Using the voltage, the polarity of wire, the number of needles of NTP as the input variables, we studied the generation characteristics of ozone and $NO_{x}$ and the particle removal efficiency in the ESPs. As the results, we found out that the concentration of ozone, $NO_{2}$ and $NO_{x}$ is increased with increasing the voltage and the number of needles, but the amount of NO is decreased. And we observed that the generation rates of ozone and $NO_{x}$ are mainly related with the corona region through the photographs. Finally the experimental results showed that the particle removal efficiency of ESP with WTP type charger is more superior to that with NTP type chargers at the same voltage.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.10a
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• pp.77-78
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• 2015

산업화로 인하여 토지의 사막화, 물부족, 오존층 파괴, 지구 온난화 등 많은 환경문제가 발생되었으며 아직 진행 중에 있다. 이에 UN에서는 환경 규제를 강화하였으며 국제해사기구(IMO:International Maritime Organization)에서는 선박의 배기가스 규제 강화를 위하여 NOx(질소산화물) 및 SOx(황산화물)의 배기량을 줄이도록 하고 있으며 2016년부터는 본격적으로 규제하려 하고 있다. 상기의 규제 물질 중 NOx를 제거하는 선택적환원촉매(SCR:Selectivity Catalytic Reduction) 시스템은 선박의 배기가스가 지나가는 통로에 요소수(Urea)를 분무하여 $260^{\circ}C$ 이상의 높은 온도에서 요소수에 있는 암모니아가 배기가스에 있는 NOx와 반응, 결합함으로서 NOx를 질소와 산소로 분리, 제거하는 방식이다. 하지만 선박의 경우 대부분 엔진이 2행정으로 배기가스 온도가 일반적으로 $180^{\circ}C{\sim}220^{\circ}C$이기 때문에 요소수에 있는 암모니아가 배기가스에 있는 NOx와 반응하지 않아 환원률이 높지 않다. 이에 우리는 초미세기포를 이용하여 낮은 온도에서도 반응할 수 있는 요소수 및 요소수 활성화 기기를 개발하여 상기의 문제점들을 최소화 할 수 있도록 하였다. 또한 SCR 시스템의 점성유동해석을 통하여 보다 효율적인 SCR 시스템의 개발을 할 수 있도록 기여하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1923-1930
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• 2012

Mn-Cu catalysts were tested for selective catalytic reduction of NOx with NH3. Influence of initial reaction temperature was studied for NOx conversion in which reaction temperature was changed three patterns. NOx conversion of catalysts calcined at 200, 300 and $340^{\circ}C$ was measured during the changing temperature. Hydrogen conversion efficiency of calcined catalysts was also measured in the $H_2$-TPR system. The deactivation effect of $SO_2$ on catalyst was investigated with the on-off control of $SO_2$ supply. The catalyst which calcined above $340^{\circ}C$ was somewhat deactivated with thermal shock. The reason of deactivation was draw from the results of surface area and hydrogen conversion.

• Korean Chemical Engineering Research
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• v.48 no.4
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• pp.540-543
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• 2010

In this study, we made low temperature plasma reactor in order to treat safely $NO_x$ which included in the gas. We investigated experimently and inspected efficiency characteristics of equipment about flow rate of reactant material and discharge input power which supplied into reactor. As a reaction gas, by using mixture gas of $NO/N_2$ and $N_2/O_2$, we setted up initial NO concentration and supplied the speed of a current to 1~4 l/min. When the amount of flow increased, reduction rate of NO was low. Also when discharge input power was high, decomposition of NO was easy. Also the longer delay time of reaction material and the higher discharge input power was, the higher decomposition energy efficiency was. And when the amount of flow was much, and the more discharge input power increased, the more ozone generated.

• Journal of Energy Engineering
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• v.29 no.2
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• pp.10-22
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• 2020

As the national demand for solving the fine dust problem has increased, the government has announced intensive measures to deal with fine dust. So recently, selective catalytic reduction(SCR) has attracted attention as a technology for removing nitrogen oxides from precursors of fine dust. In this study, the government's policies related to fine dust and the current status of market and R&D were investigated, and economic analysis by scenarios was conducted by dividing cases where SCR technology was applied to industries. The results of economic analysis for each scenario were calculated using NPV, and companies with no denitrification facilities(Case 1) introduced general SCR technologies(Scenario 1-1) and low-temperature SCR technologies(Scenario 1-2). In addition, companies that have already installed denitrification facilities(Case 2) analyzed the two categories, using the general SCR technology as it is(Scenario 2-1) and replacing it with low-temperature SCR technology(Scenario 2-2). Comparative analysis was performed based on the results of each NPV.

• Applied Chemistry for Engineering
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• v.22 no.3
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• pp.308-311
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• 2011

The reaction mechanism of selective catalytic reduction of NOx over sewage sludge char impregnated with MnOx using $NH_3$ as the reducing agent was investigated. The active Mn phase was shown to be $Mn_3O_4$ from the XRD analysis. Adsorption was the dominant NOx removal mechanism at low temperatures below $150^{\circ}C$ although reduction reaction also contributed partly to the NOx removal at $100{\sim}150^{\circ}C$. The reaction rate constants of NOx removal over non-impregnated and MnOx-impregnated active chars were compared based on experimental results. The MnOx-impregnated char was shown to have a higher reaction rate constant and a higher NOx removal efficiency due to a higher collision coefficient and a lower activation energy. The activation energy for both chars was shown to be relatively low (10~12 kJ/mol) under the experimental conditions of this study.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.588-591
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• 2004

Generally, $TiO_2$ powders absorb ultraviolet rays and make oxidation/reduction reactions on its surface. Hydroxide radical(OH), a product of photocatalyst reactions, has so strong oxidation/reduction electric potential that it can oxidize noxious gas like VOCs(Volatile Organic Compounds) and NOx. In this study, $TiO_2$ was substituted for exposed concrete to investigate the purifying degree of VOCs(Benzene, Toluene) and NOx. Anatase types of $TiO_2$ were used as photocatalyst. The sun rays and the ultraviolet were used as a light source. Anatase type $TiO_2$ was better than rutile type in purifying performance. The sunray showed the best purifying performance among the light sources. $3\%$ substitution of $TiO_2$ with the sunray was enough to purify VOCs(Benzene, Toluene) and NOx efficiently.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.5
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• pp.455-464
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• 1998

Removal teals of Soxmox were performed using low density ceramic filters doped with various catalysts. Disc type (50 mmO.Dx10 mmt) low density ceramic filters were doped with three different catalysts such as Cu to remove SOx and NOx, and Mn and Co to remove NOx. The air permeabilities and specific surface areas were 40~50cc/min.cm2.cmH2O and 4.1~8.88 m2/g, respectively. Also, the peak pore sizes of catalyst support were 3~5nm. Tests were focused to search optimum operating temperatures for different catalysts. It was found that as the CuO content increases, SOx removal efficiency was increased. NOx removal efficiencies for Mn, Cu and Co, were 85% at 30$0^{\circ}C$, 90% at 40$0^{\circ}C$ and 90% at 45$0^{\circ}C$, respectively.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.10a
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• pp.235-236
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• 1999

보일러와 같은 고정원에서 배출되는 질소산화물을 제거하기 위한 후처리 기술인 선택적촉매환원공정(SCR:Selective Catalytic Reduction)은 안정적이며 탈질효율이 높아 상업적으로 가장 많이 이용되고 있다(Bosch, 1988). 본 연구팀은 가격 및 성능 측면에서 외국산 상업용 촉매와 경쟁할 수 있는 국산 SCR 촉매의 개발을 위하여 국내에서 안료용으로 생산되는 TiO$_2$를 촉매의 담체로 이용, V$_2$O$_{5}$/TiO$_2$ 하니콤 촉매를 제조하여 촉매의 활성 및 특성을 연구 중에 있다(이정빈, 1999).(중략)