• Title/Summary/Keyword: Water-gas shift reaction

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Hydrogen Conversion of Syngas by Using WGS Reaction in a Coal Gasifier (가스화기에서 WGS 반응을 통한 합성가스의 수소 전환)

  • Lee, See Hoon;Kim, Jung Nam;Eom, Won Hyun;Baek, Il Hyun
    • Transactions of the Korean hydrogen and new energy society
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    • v.24 no.1
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    • pp.12-19
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    • 2013
  • A gasification process with pre-combustion $CO_2$ capture process, which converts coal into environment-friendly synthetic gas, might be promising option for sustainable energy conversion. In the coal gasification for power generation, coal is converted into $H_2$, CO and $CO_2$. To reduce the cost of $CO_2$ capture and to maximize hydrogen production, the removal of CO and the additional production of hydrogen might be needed. In this study, a 2l/min water gas shift system for a coal gasifier has been studied. To control the concentration of major components such as $H_2$, CO, and $CO_2$, MFCs were used in experimental apparatus. The gas concentration in these experiments was equal with syngas concentration from dry coal gasifiers ($H_2$: 25-35, CO: 60-65, $CO_2$: 5-15 vol%). The operation conditions of the WGS system were $200-400^{\circ}C$, 1-10bar. Steam/Carbon ratios were between 2.0 and 5.0. The commercial catalysts were used in the high temperature shift reactor and the low temperature shift reactor. As steam/carbon ratio increased, the conversion (1-$CO_{out}/CO_{in}$) increased from 93% to 97% at the condition of CO: 65, $H_2$: 30, $CO_2$: 5%. However the conversion decreased with increasing of gas flow and temperature. The gas concentration from LTS was $H_2$: 54.7-60.0, $CO_2$: 38.8-44.9, CO: 0.3-1%.

Attrition Characteristics of Catalysts for a High Efficiency Water Gas Shift Process (고효율 수성가스 공정을 위한 촉매 마모 특성)

  • Jo, Jun Beom;Kim, Jae Ho;Lee, See Hoon
    • Applied Chemistry for Engineering
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    • v.21 no.1
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    • pp.111-114
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    • 2010
  • In the attrition reactor for the American Society for Testing and Materials (ASTM) D5757-95, the attrition characteristics of catalysts for water gas shift reaction were investigated. The effects of attrition characteristics of low temperature shift catalysts (LTS) and high temperature shift catalysts (HTS) on fluidization phenomena and average particle size were investigated and compared with the attrition characteristics of sand particles. The particle size of catalysts was decreased and particle size distribution in attrition tube was changed due to the effect of gas injection. About 40~50 wt% samples of original catalyst particles were entrained and lost. The amount of fly ash of LTS catalyst was less than that of HTS. Also, the weight of entrained particles which had original particle size of $212{\sim}300{\mu}m$ was lower than any other cases.

The Experimental Study on the Direct Synthesis of DME (Dimethyl Ether) in the Fixed Bed Reactor. (고정층 반응기에서 DME 직접합성에 관한 실험 연구)

  • Choi, Chang Woo;Cho, Wonihl;Ju, Woo-Sung;Lee, Seung-Ho;Baek, YoungSoon;Row, Kyung Ho
    • Transactions of the Korean hydrogen and new energy society
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    • v.15 no.4
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    • pp.283-290
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    • 2004
  • The single-step process for conversion of syngas to DME give higher conversion than the syngas-to-methanol process. This arises because of a synergy among the three simultaneous reaction, methanol synthesis, methanol dehydration and water gas shift reaction, in the process. we would find the optimal condition of the process which these advantages. The optimal condition of DME synthesis reaction over a commercial $Cu/Zn/Al_2O_3$ catalyst and Hybrid catalyst in a fixed bed reactor. The syngas-to-dimethyl ether conversion was examined on various reaction condition (Temperature 473~553K, $H_2/CO$ ratio 1~3, Pressure 30'50atm, GHSV 1000~4000).

Extraction of Athabasca Oil Sand with Sub- and Supercritical Water (아임계 및 초임계수를 이용한 Athabasca 오일샌드의 추출)

  • Park, Jung Hoon;Son, Sou Hwan;Baek, Il Hyun;Nam, Sung Chan
    • Korean Chemical Engineering Research
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    • v.47 no.3
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    • pp.281-286
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    • 2009
  • Bitumen extraction and sulfur removal from Athabasca oil sand were conducted using water in sub- and supercritical condition. Bitumen yield in micro reactor was investigated in the pressure range of 15~30 MPa, the temperature of 360 and $380^{\circ}C$ and water density $0.074{\sim}0.61g/cm^3$ for 0~120 min. Bitumen yield increased with reaction pressure irrespective of temperature and dramatically increased in especially supercritical region due to hydrogen formed from water gas shift reaction. Total amount of gas product decreased with reaction pressure but the portion of sulfur and hydrogen increased a little with increasing pressure to 25 and 30 MPa. It is seen that supercritical condition was favourable to the hydrogen formation and sulfur removal. Bitumen yield and sulfur removal from original oil sand reached a maximum 22% and 40% respectively in supercritical condition(the reaction time of 60 min at $380^{\circ}C$ and 25 or 30 MPa).

Numerical study on operating parameters of autothermal reformer for hydrogen production (수소생산을 위한 자열개질기 작동조건의 수치해석 연구)

  • Park, Joon-Guen;Lee, Shin-Ku;Lim, Sung-Kwang;Bae, Joong-Myeon
    • 한국신재생에너지학회:학술대회논문집
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    • 2008.05a
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    • pp.507-510
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    • 2008
  • Characteristics of an autothermal reformer at various operating parameters have been studied in this paper. Numerical method has been used, and simulation model has been developed for the analysis. Full Combustion reaction, Steam Reforming(SR) reaction, Water-Gas Shift(WGS) reaction, and Direct Steam Reforming(DSR) reaction are assumed as dominant chemical reactions in the autothermal reformer. Simulation results are compared with experimental results for code validation. Operating parameters of the autothermal reformer are inlet temperature, Oxygen to Carbon Ratio(OCR), Steam to Carbon Ratio(SCR), and Gas Hourly Space Veolcity(GHSV). SR reaction rate decreases with low inlet temperature. If OCR is increased, $H_2$ yield is increased but optimal point is suggested. WGS reaction is activated with high SCR. When GHSV is increased, reforming efficiency is increased but pressure drop may decrease the system efficiency.

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Effect of Al Precursor Addition Time on Catalytic Characteristic of Cu/ZnO/Al2O3 Catalyst for Water Gas Shift Reaction (Water Gas Shift 반응을 위한 Cu/ZnO/Al2O3 촉매에서 Al 전구체 투입시간에 따른 촉매 특성 연구)

  • BAEK, JEONG HUN;JEONG, JEONG MIN;PARK, JI HYE;YI, KWANG BOK;RHEE, YOUNG WOO
    • Transactions of the Korean hydrogen and new energy society
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    • v.26 no.5
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    • pp.423-430
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    • 2015
  • $Cu/ZnO/Al_2O_3$ catalysts for water gas shift (WGS) reaction were synthesized by co-precipitation method with the fixed molar ratio of Cu/Zn/Al precursors as 45/45/10. Copper and zinc precursor were added into sodium carbonate solution for precipitation and aged for 24h. During the aging period, aluminum precursor was added into the aging solution with different time gap from the precipitation starting point: 6h, 12h, and 18h. The resulting catalysts were characterized with SEM, XRD, BET surface measurement, $N_2O$ chemisorption, TPR, and $NH_3$-TPD analysis. The catalytic activity tests were carried out at a GHSV of $27,986h^{-1}$ and a temperature range of 200 to $400^{\circ}C$. The catalyst morphology and crystalline structures were not affected by aluminum precursor addition time. The Cu dispersion degree, surface area, and pore diameter depended on the aging time of Cu-Zn precipitate without the presence of $Al_2O_3$ precursor. Also, the interaction between the active substance and $Al_2O_3$ became more stronger as aging duration, with Al precursor presented in the solution, increased. Therefore, it was confirmed that aluminum precursor addition time affected the catalytic characteristics and their catalytic activities.

A Study on Cu Based Catalysts for Water Gas Shift Reaction to Produce Hydrogen from Waste-Derived Synthesis Gas (폐기물 가스화 합성가스로부터 수소 생산을 위한 수성가스전이 반응용 Cu 기반 촉매 연구)

  • Na, Hyun-Suk;Jeong, Dae-Woon;Jang, Won-Jun;Lee, Yeol-Lim;Roh, Hyun-Seog
    • Transactions of the Korean hydrogen and new energy society
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    • v.25 no.3
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    • pp.227-233
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    • 2014
  • Simulated waste-derived synthesis gas has been tested for hydrogen production through water-gas shift (WGS) reaction over supported Cu catalysts prepared by co-precipitation method. $CeO_2$, $ZrO_2$, MgO, and $Al_2O_3$ were employed as supports for WGS reaction in this study. $Cu-CeO_2$ catalyst exhibited excellent catalytic activity as well as 100% $CO_2$ selectivity for WGS in severe conditions ($GHSV=40,206h^{-1}$ and CO concentration = 38.0%). In addition, $Cu-CeO_2$ catalyst showed stable CO conversion for 20h without detectable catalyst deactivation. The high activity and stability of $Cu-CeO_2$ catalyst are correlated to its easier reducibility, high oxygen mobility/storage capacity of $CeO_2$.

Experimental Assessment of Biomass Gasification for Hydrogen Production (수소생산을 위한 바이오매스 가스화 반응의 실험적 고찰)

  • Hong, Seong Gu;Um, Byung Hwan
    • Journal of The Korean Society of Agricultural Engineers
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    • v.64 no.5
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    • pp.1-8
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    • 2022
  • Hydrogen can be produced by gasification of biomass and other combustible fuels. Depending on oxydant agents, syngas or producer gas compositions become quite different. Since biomass has limited amount of hydrogen including moisture in it, the hydrogen concentration in the syngas is about 15% when air is supplied for oxidant agent. Experiments were conducted to investigate the channges in hydrogen concentrations in syngas with different oxidant agent conditions, fuel conditions, and external heat supply. Allothermal reaction resulted in higher concentrations of hydrogen with the supply of steam over air, reaching over 60%. Hydrogen is produced by water-gas and water-gas shift reactions. These reactions are endothermic and require enough heat. Autothermal reaction occurred in the downdraft gasifier used in the experiment did not provide enough heat in the reactions for hydrogen production. Steam seems a more desirable oxidant agent in producing the syngas with higher concentrations of hydrogen from biomass gasifications since nitrogen is included in syngas when air is used.

Noble metal catalysts for Water Gas Shift reaction (귀금속계열 WGS 촉매 연구)

  • Lim, Sung-Kwang;Bae, Joong-Myeon;Kim, Sun-Young
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2228-2231
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    • 2007
  • Water gas shift reactor in fuel processing is an important part that converts carbon monoxide into hydrogen. Fuel processing system for PEMFC usually has two stages of WGS reactors, which are high temperature and low temperature shifter. In this study we prepared noble metal catalysts and compared their performances with that of a commercial iron chromium oxide catalyst. Noble metal catalysts and the commercial catalyst showed quite different temperature dependence of carbon monoxide conversion. The conversion of carbon monoxide at the commercial catalyst was very low at medium temperature(${\sim}300^{\circ}C$) and increased rapidly as temperature increased while the conversion at noble metal catalysts was high in the medium temperature range and decreased as temperature increased, which is thermodynamically expected. Their characteristics agreed well with the literature published, and we are accomplishing further study for improvement of the noble metal catalysts.

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Study on Pressurized Diesel Reforming System for Polymer Electrolyte Membrane Fuel Cell in Underwater Environment (수중 환경에서 고분자 전해질 연료전지(PEMFC) 공급용 수소 생산을 위한 가압 디젤 개질시스템에 관한 연구)

  • Lee, Kwangho;Han, Gwangwoo;Bae, Joongmyeon
    • Journal of the Korea Institute of Military Science and Technology
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    • v.20 no.4
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    • pp.528-535
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    • 2017
  • Fuel cells have been spotlighted in the world for being highly efficient and environmentally friendly. A hydrogen which is the fuel of fuel cell can be obtained from a number of sources. Hydrogen source for operating the polymer electrolyte membrane fuel cell(PEMFC) in the current underwater environment, such as a submarine and unmanned underwater vehicles are currently from the metal hydride cylinder. However, metal hydride has many limitations for using hydrogen carrier, such as large volume, long charging time, limited storage capacity. To solve these problems, we suggest diesel reformer for hydrogen supply source. Diesel fuel has many advantages, such as high hydrogen storage density, easy to transport and also well-infra structure. However, conventional diesel reforming system for PEMFC requires a large volume and complex CO removal system for lowering the CO level to less than 10 ppm. In addition, because the preferential oxidation(PROX) reaction is the strong exothermic reaction, cooling load is required. By changing this PROX reactor to hydrogen separation membrane, the problem from PROX reactor can be solved. This is because hydrogen separation membranes are small and permeable to pure hydrogen. In this study, we conducted the pressurized diesel reforming and water-gas shift reaction experiment for the hydrogen separation membrane application. Then, the hydrogen permeation experiments were performed using a Pd alloy membrane for the reformate gas.