• Title/Summary/Keyword: WGS Catalyst

Search Result 51, Processing Time 0.029 seconds

Investigation of the Water Gas Shift from Reforming Gas for CO Removal (일산화탄소 저감을 위한 개질가스의 전이반응 연구)

  • Kim, Seong-Cheon;Youn, Moon-Jung;Chun, Young-Nam
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.31 no.10
    • /
    • pp.855-859
    • /
    • 2007
  • Hydrogen as an energy carrier in fuel cell offers perhaps the largest potential benefits of reduced emissions of pollutants and greenhouse gases. The generation of high-purity hydrogen from hydrocarbon fuels is essential for efficient operation of fuel cell. Reduction of carbon monoxide to an acceptable level of 10ppm involves high temperature and low temperature water gas shift (WGS), followed by selective oxidation of residual carbon monoxide. The WGS reactor was designed and tested in this study to produce hydrogen-rich gas with CO to less than 5000 ppm. In the water gas shift operation, gas emerges from the reformer is taken through a high temperature shift (HTS) catalyst to reduce the CO concentration to about $2{\sim}4%$ followed to about 5000 ppm via a low temperature shift (LTS) catalyst.

Minimization of Carbon Monoxide in the High Efficient Catalytic Shift for Fuel Cell Applications (연료전지용 고효율 촉매전이 반응의 일산화탄소 저감)

  • Park, Heon;Kim, Seong-Cheon;Chun, Young-Nam
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.29 no.5
    • /
    • pp.528-532
    • /
    • 2007
  • The generation of high-purity hydrogen from hydrocarbon fuels is essential for efficient operation of fuel cell. In general, most feasible strategies to generate hydrogen from hydrocarbon fuels consist of a reforming step to generate a mixture of $H_2$, CO, $CO_2$ and $H_2O$(steam) followed by water gas shift(WGS) and CO clean-up steps. The WGS reaction that shifts CO to $CO_2$ and simultaneously produces another mole of $H_2$ was carried out in a two-stage catalytic conversion process involving a high temperature shift(HTS) and a low temperature shift(LTS). In the WGS operation, gas emerges from the reformer is taken through a high temperature shift catalyst to reduce the CO concentration to about $3\sim4%$ followed to about 0.5% via a low temperature shift catalyst. The WGS reactor was designed and tested in this study to produce hydrogen-rich gas with CO to less than 0.5%.

Numerical Study on Operating Parameters and Shapes of a Steam Reformer for Hydrogen Production from Methane (천연가스로부터 수소를 생산하기 위한 수증기 개질기의 작동조건과 형상에 대한 수치해석 연구)

  • Park, Joong-Uen;Lee, Shin-Ku;Lim, Sung-Kwang;Bae, Joong-Myeon
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.33 no.1
    • /
    • pp.60-68
    • /
    • 2009
  • The steam reformer for hydrogen production from methane is studied by a numerical method. Langmuir- Hinshelwood model is incorporated for catalytic surface reactions, and the pseudo-homogeneous model is used to take into account local equilibrium phenomena between a catalyst and bulk gas. Dominant chemical reactions are Steam Reforming (SR) reaction, Water-Gas Shift (WGS) reaction, and Direct Steam Reforming (DSR) reaction. The numerical results are validated with experimental results at the same operating conditions. Using the validated code, parametric study has been numerically performed in view of the steam reformer performance. As increasing a wall temperature, the fuel conversion increases due to the high heat transfer rate. When Steam to Carbon Ratio (SCR) increases, the concentration of carbon monoxide decreases since WGS reaction becomes more active. When increasing Gas Hourly Space Velocity (GHSV), the fuel conversion decreases due to the heat transfer limitation and the low residence time. The reactor shape effects are also investigated. The length and radius of cylindrical reactors are changed at the same catalyst volume. The longer steam reformer is, the better steam reformer performs. However, system energy efficiency decreases due to the large pressure drop.

Kinetic Study of the Fischer-Tropsch Synthesis and Water Gas Shift Reactions over a Precipitated Iron Catalyst (철 촉매를 이용한 Fischer-Tropsch 합성 반응과 수성 가스 전환 반응에 대한 반응 속도 연구)

  • Yang, Jung-Il;Chun, Dong Hyun;Park, Ji Chan;Jung, Heon
    • Korean Chemical Engineering Research
    • /
    • v.50 no.2
    • /
    • pp.358-364
    • /
    • 2012
  • The kinetics of the Fischer-Tropsch synthesis and water gas shift reactions over a precipitated iron catalyst were studied in a 5 channel fixed-bed reactor. Experimental conditions were changed as follows: synthesis gas $H_2$/CO feed ratios of 0.5~2, reactants flow rate of 60~80 ml/min, and reaction temperature of $255{\sim}275^{\circ}C$ at a constant pressure of 1.5 MPa. The reaction rate of Fischer-Tropsch synthesis was calculated from Eley-Rideal mechanism in which the rate-determining step was the formation of the monomer species (methylene) by hydrogenation of associatively adsorbed CO. Whereas water gas shift reaction rate was determined by the formation of a formate intermediate species as the rate-determining step. As a result, the reaction rates of Fischer-Tropsch synthesis for the hydrocarbon formation and water gas shift for the $CO_2$ production were in good agreement with the experimental values, respectively. Therefore, the reaction rates ($r_{FT}$, $r_{WGS}$, $-r_{CO}$) derived from the reaction mechanisms showed good agreement both with experimental values and with some kinetic models from literature.

NUMERICAL STUDY OF STREAM REFORMING IN PRECONVERTER FOR MCFC (MCFC용 프리컨버터 수증기 개질반응의 수치연구)

  • Byun, Do-Hyun;Sohn, Chang-Hyun
    • 한국전산유체공학회:학술대회논문집
    • /
    • 2010.05a
    • /
    • pp.228-232
    • /
    • 2010
  • In this paper, various operating parameters of stream reforming process from methane in preconverter for MCFC is studied by numerical method. Commercial code is used to simulated the porous catalyst with user subroutine to model three dominant chemical reactions which are Stream Reforming(SR), Water-Gas Shift(WGS), and Direct Stram Reforming(DSR). The hydrogen production is tested with different wall temperature, Gas Hourly Space Velocity(GHSV), and different reactor shapes.

  • PDF

Optimization of Cu/CeO2 Catalyst for Single Stage Water-Gas Shift Reaction: CeO2 Production Using Cerium Hydroxy Carbonate Precursor and Selection of Optimal Cu Loading (단일 수성가스 전이 반응용 Cu/CeO2 촉매 최적화: 수산화탄산세륨 전구체를 이용한 CeO2 제조 및 최적 Cu 담지량 선정)

  • HEO YU-SEUNG;JEONG, CHANG-HOON;PARK, MIN-JU;KIM, HAK-MIN;KANG, BOO MIN;JEONG, DAE-WOON
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.32 no.6
    • /
    • pp.455-463
    • /
    • 2021
  • In this study, CeO2 support is synthesized from cerium hydroxy carbonate prepared using precipitation/digestion method using KOH and K2CO3 as the precipitants. The Cu was impregnated to CeO2 support with the different loading (Cu loading=10-40 wt. %). The prepared Cu/CeO2 catalysts were applied to a single stage water gas shift (WGS) reaction. Among the prepared catalysts, the 20Cu/CeO2 catalyst contained 20 wt.% of Cu showed the highest CO conversion (Xco=68% at 400℃). This result was mainly due to a large amount of active sites. In addition, the activity of the 20 Cu/CeO2 catalyst was maintained without being deactivated for 100 hours because of the strong interaction between Cu and CeO2. Therefore, it was confirmed that 20 Cu/CeO2 is a suitable catalyst for a single WGS reaction.

Effects of Mg Addition to Cu/Al2O3 Catalyst for Low-Temperature Water Gas Shift (LT-WGS) Reaction

  • Zakia Akter Sonia;Ji Hye Park;Wathone Oo;Kwang Bok Yi
    • Clean Technology
    • /
    • v.29 no.1
    • /
    • pp.39-45
    • /
    • 2023
  • To investigate the effects of Mg addition at different aging times and temperatures, Cu/MgO/Al2O3 catalysts were synthesized for the low-temperature water gas shift (LT-WGS) reaction. The co-precipitation method was employed to prepare the catalysts with a fixed Cu amount of 30 mol% and varied amounts of Mg/Al. Synthesized catalysts were characterized using XRD, BET, and H2-TPR analysis. Among the prepared catalysts, the highest CO conversion was achieved by the Cu/MgO/Al2O3 catalyst (30/40/30 mol%) with a 60 ℃ aging temperature and a 24 h aging time under a CO2-rich feed gas. Due to it having the lowest reduction temperature and a good dispersion of CuO, the catalyst exhibited around 65% CO conversion with a gas hourly space velocity (GHSV) of 14,089 h-1 at 300 ℃. However, it has been noted that aging temperatures greater or less than 60 ℃ and aging times longer than 24 h had an adverse impact, resulting in a lower surface area and a higher reduction temperature bulk-CuO phase, leading to lower catalytic activity. The main findings of this study confirmed that one of the main factors determining catalytic activity is the ease of reducibility in the absence of bulk-like CuO species. Finally, the long-term test revealed that the catalytic activity and stability remained constant under a high concentration of CO2 in the feed gas for 19 h with an average CO conversion of 61.83%.

Packed Bed Reactor Simulation for the Water Gas Shift Reaction in the Steam Reforming of Natural Gas (천연가스의 수증기 개질에서 수성가스 전환용 충진층 반응기의 전산모사)

  • LEE, DEUKKI
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.27 no.5
    • /
    • pp.494-502
    • /
    • 2016
  • A 1-dimensional heterogeneous reactor model with the gas-solid interfacial phase gradients was developed for the simulation of the packed bed reactor where the exothermic reversible water gas shift reaction for the natural gas steam reformed gas was proceeding in adiabatic mode. Experimental results obtained over the WGS catalyst, C18-HA, were best simulated when the frequency factor of the reaction rate constant was adjusted to a half the value reported over another WGS catalyst, EX-2248, having the same kinds of active components as the C18-HA. For the reactor of the inside diameter 158.4 mm and the bed length 650 mm, the optimum feeding temperature of the reformed gas was simulated to be $194^{\circ}C$, giving the lowest CO content in the product gas by 1.68 mol% on the basis of dried gas. For reactors more extended in the bed length, the possible lowest CO content in the product gas with the optimum feeding temperature of the reformed gas were suggested.

Pt/$Ce_{(1-x)}Zr_{(x)}O_2$ catalyst optimization for water gas shift reaction (WGS 반응용 Pt/$Ce_{(1-x)}Zr_{(x)}O_2$ 촉매 최적화)

  • Jeong, Dae-Woon;Kim, Ki-Sun;Eum, Ic-Hwan;Lee, Sung-Hun;Koo, Kee-Young;Yoon, Wang-Lai;Roh, Hyun-Seog
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2009.11a
    • /
    • pp.213-216
    • /
    • 2009
  • WGS(Water Gas Shift)반응은 일산화탄소(CO)를 이산화탄소($CO_2$)로 전환하는 반응으로 일체형 수소생산시스템의 실현을 위한 고순도 수소생산에 있어서 중요한 단계이다. WGS 반응은 열역학적 평형을 고려하여 고온전이반응(HTS: High Temperature Shift)과 저온전이반응(LTS: Low Temperature Shift) 두 단계 반응으로 진행된다. 두 단계 공정의 통합을 위해 낮은 온도에서 높은 활성을 갖는 WGS 반응용 촉매 개발이 필요하다. 최근 낮은 온도에서 높은 활성을 갖는 귀금속 촉매에 다양한 담체를 적용시킨 연구가 활발히 진행되고 있다. 선행 연구 결과, Ce-$ZrO_2$ 구조는 Ce/Zr 비에 따라 다양한 특성 변화를 관찰하였다. 따라서 낮은 온도에서 높은 활성을 갖는 WGS 반응용 촉매 제조를 위해 환원성 담체인 $CeZrO_2$에 Pt 을 담지시켜 성능을 평가하였다. 제조된 모든 담체는 공침법(Co-precipitation)으로 제조 하였으며 $500^{\circ}C$에서 6시간 소성하였다. 제조된 담체에 백금(Pt)을 함침법(Incipient Wetness Impregnate)으로 담지시켰다. 특성분석은 BET를 이용하여 표면적을 측정하였다. 촉매 반응 실험조건은 $200^{\circ}C{\sim}400^{\circ}C$ 온도범위에서 기체공간속도(GHSV: Gas Hourly Space Velocity) 45,000 ml/$h{\cdot}g-cat$ 으로 혼합가스($H_2$:60%, $N_2$:20%,$CH_4$:1%,CO:9%,$CO_2$:10%)를 흘려 반응 후 배출되는 가스를 Micro-Gas Chromatography 를 이용하여 측정하였다.

  • PDF

Effects of steam and $CO_2$ on the methanation of $H_2$-insufficient syngas (수소가 부족한 합성가스의 메탄화반응에서 스팀과 $CO_2$의 영향)

  • Kang, Suk-Hwan;Kim, Jin-Ho;Ryu, Hae-Hong;Yoo, Young-Done;Koh, Dong Jun;Baik, Joon Hyun
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2011.11a
    • /
    • pp.73.2-73.2
    • /
    • 2011
  • 합성천연가스(SNG: Synthetic Natural Gas)를 얻기 위해, 석탄 가스화로부터 얻은 합성가스는 일반적으로 수소와 일산화탄소의 비가 3.0($H_2$/CO)이 되도록 수성가스전환(WGS)반응을 거친 후 메탄화반응기로 유입되며, 가능하면 낮은 온도에서 메탄 전환율이 높은 메탄화 반응의 특성상 강한 발열반응이 수반되므로 이를 낮추는 것이 중요하다. 또한, 최종생성물내의 메탄 농도를 높이기 위해 WGS 이후 탈황과 동시에 이산화탄소를 제거하기 위한 공정이 요구된다. 본 연구에서는 정제된 합성가스의 WGS와 이산화탄소 제거가 생략된 공정을 개발하기 위해, 상업용 촉매에 대하여 수소의 농도가 낮은 합성가스를 이용하여 스팀과 이산화탄소에 대한 메탄화반응 특성을 평가하였다. 또한, 이산화탄소의 존재여부에 따라 스팀으로 메탄화반응과 WGS가 동시에 일어날 수 있는 최적의 운전조건을 얻고자 하였다.

  • PDF