뷰테인 건식 개질 반응을 위한 Ni/γ-Al₂O₃ 촉매를 이용한 촉매 공정과 촉매+플라즈마 공정 비교

조진오,좌은진,목영선,Jo, Jin-Oh,Jwa, Eunjin,Mok, Young-Sun 한국가스학회 2018 한국가스학회지 Vol.22 No.1

기존 건식 개질 반응에 사용되는 니켈 기반 촉매 공정은 활성화 온도가 높고, 촉매 표면의 활성점에 탄소 침착 및 금속 소결 현상 등의 문제점이 있다. 이에 본 연구에서는 촉매공정에 DBD 플라즈마 공정이 결합된 촉매+플라즈마 공정을 이용하여 뷰테인 건식 개질 반응 특성을 조사하고 기존 촉매 공정과 비교 분석하였다. 촉매의 특성을 파악하기 위해 비표면적 분석기, XRD, SEM 및 TEM 등을 사용하여 물리 화학적 특성을 조사 하였다. $580^{\circ}C$에서 $10%Ni/{\gamma}-Al_2O_3$촉매를 사용한 경우 촉매+플라즈마 공정의 경우 촉매 단독 공정에 비해 이산화탄소와 뷰테인 전환율이 각각 27%, 39%향상되었다. 촉매+플라즈마 공정의 경우 플라즈마에 의해 생성된 다양한 활성종의 영향으로 이산화탄소와 뷰테인 전환율 및 생성되는 수소 농도가 증가하였으며, 뷰테인 건식 개질 반응 과정에서 플라즈마에 의해 니켈 촉매의 크기가 감소하고 분산도가 증가하여 반응 효율이 향상되는 것으로 판단되었다. Conventional nickel-based catalyst processes used for dry reforming reactions have high activation temperatures and problems such as carbon deposition and metal sintering on the active sites of the catalyst surface. In this study, the characteristics of butane dry reforming reaction were investigated by using DBD plasma combined with catalytic process and compared with existing catalyst alone process. The physical and chemical properties of the catalysts were investigated using a surface area & pore size analyzer, XRD, SEM and TEM. Using $10%Ni/{\gamma}-Al_2O_3$ at $580^{\circ}C$, in the case of the catalyst+plasma process, the conversion of carbon dioxide and butane were improved by about 30% than catalyst alone process. When the catalyst+plasma process, the conversion of carbon dioxide and butane and the hydrogen production concentration are enhanced by the influence of various active species generated by the plasma. In addition, it was found that the particle size of the catalyst is decreased by the plasma in the reaction process, and the degree of dispersion of the catalyst is increased to improve the efficiency.

플라즈마를 이용한 상수원 이취미 및 독성물질 분해 연구

조진오 ( Jin Oh Jo ),김상돈 ( Sang Don Kim ),임병진 ( Byung Jin Lim ),현영진 ( Young Jin Hyun ),목영선 ( Young Sun Mok ) 한국공업화학회 2013 공업화학 Vol.24 No.5

This study investigated the degradation of taste-and-odor compounds and toxins using dielectric barrier discharge plasma. The degradation of taste-and-odor compounds was conducted on geosmin and 2-methyl isoborneol (2-MIB), and the toxins investigated were microcystin-LR (MC-LR), microcystin-RR (MC-RR), microcystin-YR (MC-YR) and anatoxin-a. Largely depending on the type of gas fed to the plasma reactor, the degradation efficiencies of the taste-and-odor compounds decreased in order of oxygen (100%) > dry air (96%) > nitrogen (5%) for geosmin and in order of oxygen (100%) > dry air (94%) > nitrogen (2%) for 2-MIB on the basis of 150 s reaction time. This result suggests that the oxidative reactive species generated during plasma treatment, especially long-lived ozone, are mainly responsible for the degradation of these compounds. When using oxygen as the feed gas, geosmin and 2-MIB were totally degraded within 150 s, microcystins within 10 s, and anatoxin- a within 30 s. It was found that the taste-and-odor compounds and toxins were degraded more rapidly in real lake water than in distilled water.

플라즈마-탄화수소 선택적 촉매환원공정을 이용한 질소산화물 저감 연구

조진오 ( Jin-oh Jo ),목영선 ( Young Sun Mok ) 한국공업화학회 2018 공업화학 Vol.29 No.1

본 연구에서는 온도가 큰 폭으로 변화하는 배기가스에 대응하기 위하여 플라즈마 촉매 공정을 이용하여 넓은 온도범위(150~500 ℃)에서 질소산화물(NO_x)의 전환효율을 향상시키고자 하였다. 촉매 자체의 활성이 높은 고온에서는 NO_x 저감이 효과적으로 일어나므로 고온 영역에서는 플라즈마 발생을 중지한 채 운전하고, 저온영역에서는 촉매상에 플라즈마를 발생시켜 NO_x 전환효율을 증가시켰다. 촉매의 종류, 반응온도, 환원제(n-헵테인)의 농도 및 에너지 밀도의 변화가 NO_x 전환효율에 미치는 영향을 조사하였다. 다양한 촉매를 비교분석한 결과, 고온에서 촉매에 의한 NO_x 전환효율은 Ag-Zn/γ-Al₂O₃ 촉매의 경우가 90% 이상으로 가장 우수하였다. 저온 영역에서는 탄화수소 선택적 환원 공정에 의해 NO_x가 거의 제거되지 않았으나, 플라즈마를 촉매상에서 발생시킬 경우 약 90%의 높은 NO_x 전환효율을 나타내었다. 배기가스의 온도변화에 대응하여 플라즈마를 촉매상에 생성시켜 운전할 경우 150~500 ℃에서 NO_x 전환효율을 높게 유지할 수 있다. A plasma-catalytic combined process was used as an attempt to improve the conversion efficiency of nitrogen oxides (NO_x) over a wide temperature range (150~500 ℃) to cope with the exhaust gas whose temperature varies greatly. Since the cata-lytic NO_x reduction is effective at high temperatures where the activity of the catalyst itself is high, the NO_x reduction was carried out without plasma generation in the high temperature region. On the other hand, in the low temperature region, the plasma was created in the catalyst bed to make up for the decreased catalytic activity, thereby increasing the NO_x conversion efficiency. Effects of the types of catalysts, the reaction temperature, the concentration of the reducing agent (n-heptane), and the energy density on NO_x conversion efficiency were examined. As a result of comparative analysis of various catalysts, the catalytic NO_x conversion efficiency in the high temperature region was the highest in the case of the Ag-Zn/γ-Al₂O₃ catalyst of more than 90%. In the low temperature region, NO_x was hardly removed by the hydrocarbon selective reduction process, but when the plasma was generated in the catalyst bed, the NO_x conversion sharply increased to about 90%. The NO_x conversion can be maintained high at temperatures of 150~500 ℃ by the combination of plasma in accordance with the temperature change of the exhaust gas.

다공질 세라믹지지 촉매 상에서의 플라즈마 방전을 이용한 휘발성유기화합물의 분해

조진오 ( Jin Oh Jo ),이상백 ( Sang Baek Lee ),장동룡 ( Dong Lyong Jang ),목영선 ( Young Sun Mok ) 한국공업화학회 2013 공업화학 Vol.24 No.4

Electrical discharge plasma created in a multi-channel porous ceramic membrane-supported catalyst was applied to the decomposition of a volatile organic compound (VOC). For the purpose of improving the oxidation capability, the ceramic membrane used as a low-pressure drop catalyst support was loaded with zinc oxide photocatalyst by the incipient wetness impregnation method. Alternating current-driven discharge plasma was created inside the porous ceramic membrane to produce reactive species such as radicals, ozone, ions and excited molecules available for the decomposition of VOC. As the voltage supplied to the reactor increased, the plasma discharge gradually propagated in the radial direction, creating an uniform plasma in the entire ceramic membrane above a certain voltage. Ethylene was used as a model VOC. The ethylene decomposition efficiency was examined with experimental variables such as the specific energy density, inlet ethylene concentration and zinc oxide loading. When compared at the identical energy density, the decomposition efficiency obtained with the zinc oxide loaded ceramic membrane was substantially higher than that of the bare membrane case. Both nitrogen and oxygen played an important role in initiating the decomposition of ethylene. The rate of the decomposition is governed by the quantity of reactive species generated by the plasma, and a strong dependence of the decomposition efficiency on the initial concentration was observed.

촉매-플라즈마 반응 시스템을 이용한 아이소프로필 알코올 산화

조진오 ( Jin Oh Jo ),목영선 ( Young Sun Mok ) 한국공업화학회 2014 공업화학 Vol.25 No.5

A catalytic plasma reactor was employed for the oxidation of isopropyl alcohol (IPA) classified as a volatile organic compound(VOC). Copper oxide (Cu : 0.5% (w/w)) supported on a multichannel porous ceramic consisting of α-Al2O3 was used as a catalyst, which was directly exposed to the plasma created in it. The effects of discharge voltage and reaction temperature on the concentrations of IPA and its byproducts were examined to understand the behavior of the catalytic plasma reactor. Without thermal insulation, the reactor temperature increased up to 120 ℃ at an applied voltage of 17 kV (discharge power: 28 W), and the IPA at a flow rate of 1 L min-1 (O2 : 10% (v/v); IPA : 1000 ppm) was completely removed. At temperatures below 120 ℃, however, besides the desirable product CO2, several unwanted byproducts such as acetone, formaldehyde and CO were also formed from IPA. On the other hand, when the reactor was thermally insulated, the plasma discharge increased the temperature up to 265 ℃ under the same condition and most of IPA was oxidized to CO2. Without loading CuO on the ceramic support, the plasma discharge in the thermally insulated reactor produced nearly equal amounts of CO2 and CO. On comparison, with the catalyst alone (temperature : 265 ℃), more than 70% of the removed IPA was simply converted into another type of VOC (acetone), indicating that the catalyst assisted by the plasma is more effective in the oxidation of IPA than that of the catalyst-alone process.

코로나 방전 플라즈마를 이용한 화산암재 분말 살균

조진오 ( Jin Oh Jo ),이호원 ( Ho Won Lee ),목영선 ( Young Sun Mok ) 한국공업화학회 2014 공업화학 Vol.25 No.4

Atmospheric-pressure nonthermal corona discharge plasma was applied to the sterilization of biologically contaminated scoriapowder. Escherichia coli (E. coli) culture solution was uniformly sprayed throughout the scoria powder for artificial inoculation,which was well mixed to ensure uniformity of the batch. The effect of the key parameters such as discharge power,treatment time, type of gas and electrode distance on the sterilization efficiency was examined and discussed. The experimentalresults revealed that the plasma treatment was very effective for the sterilization of scoria powder; 5-min treatment at 15 Wcould sterilize more than 99.9% of E. coli inoculated into the scoria powder. Increasing the discharge power, treatment timeor applied voltage led to an improvement in the sterilization efficiency. The effect of type of gas on the sterilization efficiencywas in order of oxygen, synthetic air (20% oxygen) and nitrogen from high to low. The inactivation of E. coli under theinfluence of corona discharge plasma can be explained by cell membrane erosion or etching resulting from UV and reactiveoxidizing species (oxygen radical, OH radical, ozone, etc.), and the destruction of E. coli cell membrane by the physical actionof numerous corona streamers.

뷰테인 건식 개질 반응을 위한 Ni/γ-Al₂O₃ 촉매를 이용한 촉매 공정과 촉매+플라즈마 공정 비교

조진오(Jin-Oh Jo),좌은진(Eunjin Jwa),목영선(Young-Sun Mok) 한국가스학회 2018 한국가스학회지 Vol.22 No.1

기존 건식 개질 반응에 사용되는 니켈 기반 촉매 공정은 활성화 온도가 높고, 촉매 표면의 활성점에 탄소 침착 및 금속 소결 현상 등의 문제점이 있다. 이에 본 연구에서는 촉매공정에 DBD 플라즈마 공정이 결합된 촉매+플라즈마 공정을 이용하여 뷰테인 건식 개질 반응 특성을 조사하고 기존 촉매 공정과 비교 분석하였다. 촉매의 특성을 파악하기 위해 비표면적 분석기, XRD, SEM 및 TEM 등을 사용하여 물리 화학적 특성을 조사 하였다. 580℃에서 10%Ni/γ-Al₂O₃촉매를 사용한 경우 촉매+플라즈마 공정의 경우 촉매 단독 공정에 비해 이산화탄소와 뷰테인 전환율이 각각 27%, 39%향상되었다. 촉매+플라즈마 공정의 경우 플라즈마에 의해 생성된 다양한 활성종의 영향으로 이산화탄소와 뷰테인 전환율 및 생성되는 수소 농도가 증가하였으며, 뷰테인 건식 개질 반응과정에서 플라즈마에 의해 니켈 촉매의 크기가 감소하고 분산도가 증가하여 반응 효율이 향상되는 것으로 판단되었다. Conventional nickel-based catalyst processes used for dry reforming reactions have high activation temperatures and problems such as carbon deposition and metal sintering on the active sites of the catalyst surface. In this study, the characteristics of butane dry reforming reaction were investigated by using DBD plasma combined with catalytic process and compared with existing catalyst alone process. The physical and chemical properties of the catalysts were investigated using a surface area & pore size analyzer, XRD, SEM and TEM. Using 10%Ni/γ-Al₂O₃ at 580°C, in the case of the catalyst+plasma process, the conversion of carbon dioxide and butane were improved by about 30% than catalyst alone process. When the catalyst+plasma process, the conversion of carbon dioxide and butane and the hydrogen production concentration are enhanced by the influence of various active species generated by the plasma. In addition, it was found that the particle size of the catalyst is decreased by the plasma in the reaction process, and the degree of dispersion of the catalyst is increased to improve the efficiency.

수중 전기방전을 이용한 에틸렌디아민테트라아세트산 폐액의 처리

조진오(Jin Oh Jo),목영선(Young Sun Mok),강덕원(Duk Won Kang) 大韓環境工學會 2007 대한환경공학회지 Vol.29 No.5

본 연구에서는 저전압 및 고전류에 의해 운전되는 수중 전기방전 기술을 이용하여 고농도(70,000 mg/L) 철(III)-에틸렌디아민테트라아세트산(Fe(III)-EDTA) 폐액을 처리하였다. 폐액내의 두 전극사이에 교류전압을 인가하면 폐액이 저항체의 역할을 하므로 전극주변 폐액의 온도가 빠르게 상승하며 동시에 전기화학반응에 의해 물이 분해되어 산소 및 수소 기체가 생성된다. 물의 기화 및 전기분해에 의해 생성된 기체가 전극주변을 감싸게 되면 이 기체층에서 강력한 전기방전이 일어난다. 과산화수소의 주입이 없을 때는 전기방전에 의해 약 50%의 Fe(III)-EDTA가 제거되었으며, 과산화수소 주입량이 증가됨에 따라 Fe(III)-EDTA 제거효율이 크게 증가하였다. 초기 Fe(III)-EDTA에 대한 과산화수소의 몰비가 24.7 이상일 때는 1 kWh의 에너지로 80 g 이상의 Fe(III)-EDTA를 제거할 수 있었다. 텅스텐 전극과 철전극을 비교한 결과 전극재질이 Fe(III)-EDTA 제거효율에 미치는 영향은 거의 없는 것으로 나타났다. 본 연구의 공정에서는 초기 Fe(III)-EDTA에 대한 과산화수소의 몰비가 24.7 이상일 때 30분 이내에 Fe(III)-EDTA 제거반응이 완료되었다. This study investigated the treatment of liquid waste containing highly concentrated iron(III)-ethylenediaminetetraaceticacid(Fe(III)-EDTA) of 70,000 mg/L by an underwater electrical discharge process using low voltage and high current. When AC voltage is applied to the discharging electrode with the other electrode grounded, the temperature of the liquid waste around the discharging electrode rapidly increases, and at the same time, hydrogen and oxygen gases are formed at the electrode as a result of electrochemical reactions. Ultimately, gases formed by vaporization of water and electrochemical reactions cover the electrode. Since the liquid waste is electrically conductive, it elongates the ground electrode up to the border of the gas layer, where electrical discharge occurs. Without hydrogen peroxide, electrical discharge was able to remove about 50% of Fe(III)-EDTA. As the concentration of hydrogen peroxide added increased, the removal efficiency of Fe(III)-EDTA increased. When the molar ratio of hydrogen peroxide to the initial Fe(III)-EDTA was higher than 24.7, more than 80 g of Fe(III)-EDTA was removed with an energy of 1 kWh. A comparison between tungsten and steel electrodes showed that electrode material did not affect the Fe(III)-EDTA removal. In the present underwater electrical discharge process, the removal of Fe(III)-EDTA was completed within 30 min at molar ratios of hydrogen peroxide to the initial Fe(III)-EDTA higher than 24.7.

수중 유전체장벽방전 플라즈마를 이용한 아조 염색폐수 색도제거

조진오 ( Jin Oh Jo ),이상백 ( Sang Baek Lee ),목영선 ( Young Sun Mok ) 한국공업화학회 2013 공업화학 Vol.24 No.5

This work investigated the environmental application of an underwater dielectric barrier discharge plasma reactor consisting of a porous hydrophobic ceramic tube to the decolorization of an azo dyeing wastewater. The reactive species generated by the plasma are mostly short-lived, which also need to be transferred to the wastewater right after the formation. Moreover, the gas-liquid interfacial area should be as large as possible to increase the decolorization rate. The arrangement of the present wastewater treatment system capable of immediately dispersing the plasmatic gas as tiny bubbles makes it possible to effectively decolorize the dyeing wastewater alongside consuming less amount of electrical energy. The effect of discharge power, gas flow rate, dissolved anion and initial dye concentration on the decolorization was examined with dry air for the creation of plasma and amaranth as an azo dye. At a gas flow rate of 1.5 L min -1 , the good contact between the plasmatic gas and the wastewater was achieved, resulting in rapid decolorization. For an initial dye concentration of 40.2 μmol L -1 (volume: 0.8 L; discharge power: 3.37 W), it took about 25 min to attain a decolorization efficiency of above 99%. Besides, the decolorization rate increased with decreasing the initial dye concentration or increasing the discharge power. The presence of chlorine anion appeared to slightly enhance the decolorization rate, whereas the effect of dissolved nitrate anion was negligible.

비스페놀 A 수용액의 대기압 플라즈마 처리

조진오 ( Jin-oh Jo ),최경윤 ( Kyeong Yun Choi ),김수지 ( Suji Gim ),목영선 ( Young Sun Mok ) 한국공업화학회 2015 공업화학 Vol.26 No.3

This work investigated the plasma treatment of aqueous bisphenol A (BPA) solution and mineralization pathways. For the effective contact between plasmatic gas and aqueous BPA solution, the plasma was created inside a porous ceramic tube, which was uniformly dispersed into the aqueous solution through micro-pores of the ceramic tube. Effects of the gas flow rate, applied voltage and treatment time on the decomposition of BPA were examined, and analyses using ultraviolet (UV) spectroscopy, ion chromatography and gas chromatography-mass spectrometry were also performed to elucidate mineralization mechanisms. The appropriate gas flow rate was around 1.0 L min-1; when the gas flow rate was too high or too low, the BPA decomposition performance at a given electric power decreased. The increase in the voltage improves the BPA decomposition due to the increased electric power, but the energy required to remove BPA was similar, regardless of the voltage. Under the condition of 1.0 L min-1 and 20.8 kV, BPA at an initial concentration of 10 mg L-1 (volume : 1 L) was successfully treated within 30 min. The intermediates produced by the attack of ozone and hydroxyl radicals on BPA were further oxidized to stable compounds such as acetate, formate and oxalate.