• Title/Summary/Keyword: honeycomb monolith

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A Study of Non-thermal Plasma Generation on a Photocatalytic Reactor Using a Ceramic Honeycomb Monolith Substrate (세라믹 벌집형 담체를 사용한 광촉매 반응기의 플라즈마 생성에 관한 연구)

  • 손건석;윤승원;고성혁;김대중;송재원;이귀영
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.2
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    • pp.48-54
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    • 2002
  • Since photocatalysts are activated by lights of UV wavelengths, plasma is alternatively used as a light source for a photocatalytic reactor. Light intensity generated by plasma is proportional to the surface area of catalytic material, and this, in many practical applications, is prescribed by the geometry of a plasma generator. Thus, it is crucial to increase the surface area far sufficient light intensity for photocatalytic reaction. For example, in a pack-bed type reactor, multitudes of beads are used as a substrate in order to increase the surface area. Honeycomb monolith type substrate, which has very good surface area to volume ratio, has been difficult to apply plasma as a light source due to the fact that light penetration depth through the honeycomb monolith was too short to cover sufficient area, thus resulting in poor intensity for photocatalytic reaction. In this study, nonthermal plasma generation through a photocatalytic reactor of honeycomb monolith substrate is investigated to lengthen this short penetration depth. The ceramic honeycomb monolith substrate used in this study has the same length as a three way catalyst used fur automotive applications, and it is shown that sufficient light intensity for photocatalytic reaction can also be obtained with honeycomb monolith type reactor.

A Fundamental Study for a Photocatalytic Reactor Design (광촉매 반응치 설계를 위한 기초 연구)

  • 손건석;윤승원;고성혁;김대중;송재원;이귀영
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.2
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    • pp.40-47
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    • 2002
  • Because UV wavelength lights can activate photocatalysts, plasma is used as a light source of a photocatalytic reactor. Even though plasma has good intensity for photo reaction, substrate of catalyst coating was limited by the geometry of plasma generator. Usually bead type substrate was used for a pack bed type reactor. Honeycomb monolith type substrate was used with UV lamps instead plasma, due to the light penetration the honeycomb monolith length was too short to show good activity In this study a photocatalytic reactor, which is using a honeycomb monolith substrate, was investigated with plasma as an activation light source. As a parametric study the effects of 1311owing factors on plasma generation and power consumption are examined; supply voltage, substrate length, environment condition, catalyst loading and ratio. Using the test results, the practicability test was done with simulated synthetic gases representing bad smells and automotive exhaust gases.

Honeycomb-structured Fe2O3 Catalysts for Low-temperature CO Oxidation (산화철 허니컴 구조 촉매를 활용한 일산화탄소 저온 산화반응 연구)

  • Lee, Donghun;Uhm, Sunghyun
    • Applied Chemistry for Engineering
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    • v.30 no.2
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    • pp.151-154
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    • 2019
  • We report the effective fabrication processes for more practical monolith catalysts consisting of washcoated alumina on a cordierite honeycomb monolith (CHM) and iron oxides nanoparticles in the alumina prepared by a simple dry coating method. It is confirmed that iron oxide nanoparticles were well deposited into the mesopore of washcoated alumina which is formed on the corner wall of honeycomb channel, and the effect of annealing temperature was evaluated for carbon monoxide oxidation catalysts. $Fe_2O_3/{\gamma}-Al_2O_3/CHM$ catalysts annealed at $350^{\circ}C$ exhibited the most enhanced catalytic activity, 100% conversion efficiency at more than $200^{\circ}C$ operating temperature.

Honeycomb Monolith Coated with Mo(VI)/ZrO2 as a Versatile Catalyst System for Liquid Phase Transesterification

  • Thimmaraju, N.;Pratap, S.R.;Senthilkumar, M.;Mohamed Shamshuddin, S.Z.
    • Journal of the Korean Chemical Society
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    • v.56 no.5
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    • pp.563-570
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    • 2012
  • Solid acid Mo(VI)/$ZrO_2$ with 2-10% Mo(VI) was coated on honeycomb monoliths by impregnation method. These catalytic materials were characterized by BET, $NH_3$-TPD/n-butylamine back titration, PXRD and SEM techniques. Phenyl salicylate (Salol) was synthesized via transesterification of methyl salicylate and phenol over these catalytic materials. An excellent yield (91.0%) of salol was obtained under specific reaction conditions. The effect of poisoning of acid sites of the catalytic material by adsorbing different bases and its effect on total surface acidity, powder XRD phases and catalytic activity was studied. A triangular correlation between the surface acidity, powder XRD phases and catalytic activity of Mo(VI)/$ZrO_2$ was observed. The thermally regenerated catalytic material was reused repeatedly with a consistent high yield of salol.

Study on the Simple Preparation Method of Honeycomb-structured Catalysts by Temperature-regulated Chemical Vapor Deposition (온도조절 화학기상증착법을 활용한 대용량 허니컴 구조촉매 제조 연구)

  • Seo, Minhye;Kim, Soong Yeon;Kim, Young Dok;Uhm, Sunghyun
    • Applied Chemistry for Engineering
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    • v.29 no.1
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    • pp.18-21
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    • 2018
  • We report on the simple preparation method of large-scale structured catalysts by temperature-regulated chemical vapor deposition with a high cell-density ceramic honeycomb monolith. And the feasibility for dry reforming of methane catalysts was evaluated. The NiO/Cordierite (CDR) catalyst was prepared by controlling coating conditions at each temperature step, leading to a conformal deposition of NiO inside the cordierite honeycomb monolith with the cell density of 600 cpsi. The catalytic conversion of $CH_4$ and $CO_2$ for dry reforming of methane were about 83% and 90% with gas hourly space velocity of $10,000h^{-1}$ at $800^{\circ}C$, respectively. As a result, it exhibited that the temperature-regulated chemical vapor deposition method can be expedient for the preparation of large-scale structured catalysts.

Catalytic Combustion Characteristics of Hydrogen-Air Premixture in a Millimeter Scale Monolith Coated with Platinum (밀리미터 스케일 촉매 연소기에서의 수소-공기 예혼합 가스의 촉매 연소 특성)

  • Choi, Won-Young;Kwon, Se-Jin
    • Journal of the Korean Society of Combustion
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    • v.10 no.1
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    • pp.20-26
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    • 2005
  • In the present study, catalytic combustion of hydrogen-air premixture in a millimeter scale monolith coated with Pt catalyst was investigated. As the combustor size decreases, the heat loss increases in proportion with the inverse of the scale of combustion chamber and combustion efficiency decreases in a conventional type of combustor. Combustion reaction assisted by catalyst can reduce the heat loss by decreasing the reaction temperature at which catalytic conversion takes place. Another advantage of catalytic combustion is that ignition is not required. Platinum was coated by incipient wetness method on a millimeter scale monolith with cell size of $1{\times}1mm$. Using this monolith as the core of the reaction chamber, temperatures were recorded at various locations along the flow direction. Burnt gas was passed to a gas chromatography system to measure the hydrogen content after the reaction. The measurements were made at various volume flow rate of the fuel-air premixture. The gas chromatography results showed the reaction was complete at all the test conditions and the reacting species penetrated the laminar boundary layer at the honeycomb and made contact with the catalyst coated surface. At all the measuring locations, the record showed monotonous increase of temperature during the measurement duration. And the temperature profile showed that the peak temperature is reached at the point nearest to the gas inlet and decreasing temperature along the flow direction.

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2-Step Thermochemical Water Splitting on a Active Material Washcoated Monolith Using a Solar Simulator as Heat Source (인공태양을 이용한 모노리스 적용 반응기에서 2단계 열화학적 물분해 연구)

  • Kang, Kyoung-Soo;Kim, Chang-Hee;Park, Chu-Sik
    • Transactions of the Korean hydrogen and new energy society
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    • v.18 no.2
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    • pp.109-115
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    • 2007
  • Solar energy conversion to hydrogen was carried out via a two-step thermochemical water splitting using metal oxide redox pair. To simulate the solar radiation, a 7 kW short arc Xe-lamp was used. Partially reduced iron oxide and cerium oxide have the water splitting ability, respectively. So, $Fe_3O_4$ supported on $CeO_2$ was selected as the active material. $Fe_3O_4/CeO_2$(20 wt/80 wt%) was prepared by impregnation method, then the active material was washcoated on the ceramic honeycomb monolith made of mullite and cordierite. Oxygen was released at the reduction step($1673{\sim}1823\;K$) and hydrogen was produced from water at lower temperature($873{\sim}1273\;K$). The result demonstrate the possibility of the 2-step thermochemical water splitting hydrogen production by the active material washcoated monolith. And hydrogen and oxygen was produced separately without any separation process in a monolith installed reactor. But the SEM and EDX analysis results revealed that the support used in this experiment is not suitable due to the thermal instability and coating material migration.

Development of $H_2O_2$ Monopropellant Thruster with Monolith Support (모노리스를 이용한 과산화수소 단일추진제 추력기 개발)

  • An, Sung-Yong;Jin, Jung-Kun;Kwon, Se-Jin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.11 no.1
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    • pp.18-26
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    • 2007
  • A development of monopropellant thruster for microsatellite that uses concentrated hydrogen peroxide is described. Catalyst, the most important component in the thruster, was prepared and coated on a monolith honeycomb. Performance evaluation of thruster was peformed by considering the efficiency of characteristic velocity and ignition delay. As a result, 96.0% of $C^*$ efficiency was obtained at designed propellant flowrate and steady state operating condition.

Effects of Explosion Pipe Structure on the Flame Propagation Velocity and the Quenching Ability of Ceramic Honeycomb Monolity (화염전파속도에 대한 폭발관 구조의 영향과 세라믹 소염소자의 소염성능)

  • 김영수;신창섭
    • Journal of the Korean Society of Safety
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    • v.10 no.3
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    • pp.56-61
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    • 1995
  • The behaviors of flame propagation and quenching in a pipe were investigated to make a design criteria of flame arrester. The effects of sealing condition of pipe end, pipe diameter and lengh were studied, and also the effects of thickness of ceramic honycomb monolith on the quenching ability were discussed. Experimental results showed that the flame velocity in case of closed pipe was increased about twenty times faster than that of opened and the sealing coditions of pipe end and length showed significant effects on it. The quenching ability of ceramic honycomb monolith was Increased with thickness and coincided well with Palmer's equation.

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An Optimization Study on a Low-temperature De-NOx Catalyst Coated on Metallic Monolith for Steel Plant Applications (제철소 적용을 위한 저온형 금속지지체 탈질 코팅촉매 최적화 연구)

  • Lee, Chul-Ho;Choi, Jae Hyung;Kim, Myeong Soo;Seo, Byeong Han;Kang, Cheul Hui;Lim, Dong-Ha
    • Clean Technology
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    • v.27 no.4
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    • pp.332-340
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    • 2021
  • With the recent reinforcement of emission standards, it is necessary to make efforts to reduce NOx from air pollutant-emitting workplaces. The NOx reduction method mainly used in industrial facilities is selective catalytic reduction (SCR), and the most commercial SCR catalyst is the ceramic honeycomb catalyst. This study was carried out to reduce the NOx emitted from steel plants by applying De-NOx catalyst coated on metallic monolith. The De-NOx catalyst was synthesized through the optimized coating technique, and the coated catalyst was uniformly and strongly adhered onto the surface of the metallic monolith according to the air jet erosion and bending test. Due to the good thermal conductivity of metallic monolith, the De-NOx catalyst coated on metallic monolith showed good De-NOx efficiency at low temperatures (200 ~ 250 ℃). In addition, the optimal amount of catalyst coating on the metallic monolith surface was confirmed for the design of an economical catalyst. Based on these results, the De-NOx catalyst of commercial grade size was tested in a semi-pilot De-NOx performance facility under a simulated gas similar to the exhaust gas emitted from a steel plant. Even at a low temperature (200 ℃), it showed excellent performance satisfying the emission standard (less than 60 ppm). Therefore, the De-NOx catalyst coated metallic monolith has good physical and chemical properties and showed a good De-NOx efficiency even with the minimum amount of catalyst. Additionally, it was possible to compact and downsize the SCR reactor through the application of a high-density cell. Therefore, we suggest that the proposed De-NOx catalyst coated metallic monolith may be a good alternative De-NOx catalyst for industrial uses such as steel plants, thermal power plants, incineration plants ships, and construction machinery.