• Applied Chemistry for Engineering
• /
• v.25 no.2
• /
• pp.204-208
• /
• 2014

This study investigated the effect of hydrogen permeance and selectivity, catalyst amount, $H_2O/CO$ ratio in a feed stream, and Ar sweep gas on the performance of a water gas shift reaction in a membrane reactor. It was observed that a minimum hydrogen selectivity of 100 was needed in a membrane reactor to obtain a hydrogen yield higher than the one at equilibrium and the hydrogen yield enhancement gradually decreased as the hydrogen permeance increased. The CO conversion in a membrane reactor initially increased with the catalyst amount and reached a plateau later for a membrane reactor with a low hydrogen permeance while the high CO conversion independent of a catalyst amount was observed for a membrane reactor with a high hydrogen permeance. For the $H_2O/CO$ ratio in a feed stream higher than 1.5, a hydrogen permeance had little effect on the CO conversion in a membrane reactor and it was found that a minimum Ar molar flow rate of $6.7{\times}10^{-6}mol\;s^{-1}$ was needed to achieve the CO conversion higher than the one at equilibrium in a membrane reactor.

• Transactions of the Korean hydrogen and new energy society
• /
• v.27 no.6
• /
• pp.628-635
• /
• 2016

Natural gas reformed hydrogen is used as a fuel of fuel cell vehicle, PSA process is used for the purification of reformed hydrogen. In this study, the performance of CO adsorbent in PSA process was evaluated. Zeolite adsorbents used in the commercial PSA process is used. The physical and chemical properties of adsorbents were characterized using BET apparatus, XRD, and FE-SEM. The breakthrough apparatus modified from GC was used for the CO breakthrough experiment, the quantitative analysis of CO adsorption capacity was performed using CO breakthrough curve. Zeolite 10X and 13X showed superior CO adsorption capacity than activated alumina. The CO adsorption capacity of zeolite 10X is more than twice of zeolite 13X even the BET surface area is low. It seems that the presence of $Ca^{2+}$ cation in zeolite 10X is beneficial to the adsorption of CO.

• Transactions of the Korean hydrogen and new energy society
• /
• v.20 no.2
• /
• pp.168-178
• /
• 2009

To check feasibility of SEWGS(Sorption Enhanced Water Gas Shift) system, conceptual design and sensitivity analysis of operating variables have been investigated based on a design program of two-interconnected fluidized bed. Based on the conceptual design results, the optimum configuration for SEWGS was considered. Among three configurations, bubbling beds system was selected as the best configuration. Process design results indicate that the SEWGS system is compact and feasible. Based on the selected operating conditions, the effects of variables such as pressure, $CO_2$ capture capacity, solid inventory, CO conversion and $CO_2$ capture efficiency have been investigated as well.

• Plant Journal
• /
• v.14 no.1
• /
• pp.4-18
• /
• 2018

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 2010.04a
• /
• pp.188-188
• /
• 2010

수소 에너지는 화석연료의 한정된 매장량과 연소시 발생되는 환경문제를 해결하기 위해 가장 이상적인 대체에너지로서 주목을 받고 있다. 그러나 현재까지의 기술로는 경제성 있는 수소 제조가 쉽지 않다. 그 방법 중 바이오매스 및 유기성폐기물의 가스화를 통한 수소제조분야는 자원의 재순환, 페기물 처리, 열원의 이용, 직접적인 $CO_2$ 삭감 등의 부수적인 효과가 높아 경제성 있는 수소제조법으로 평가되고 있다. 이에 본 연구에서는 수소 생산을 목적으로 하는 가스화기와 초고온개질기로 구성된 Twin-Bed 가스화 시스템을 개발하고, 이를 이용한 Wood pellet(미송)의 가스화 특성 및 생성 가스의 초고온개질 특성을 고찰하는 것을 목적으로 한다. 가스화기의 시간변화에 따른 생성 가스 수율에 대한 결과, 생성 가스 수율은 약 20분경과 후 안정화되었으며, 실험 2시간 동안의 $H_2,\;CH_4,\;CO,\;CO_2$의 평균 수율은 각각 17.77, 11.94, 42.13, 28.16 Vol.%의 결과를 보였다. 가스화기로부터 생성된 가스는 down-draft 형태의 고온개질기로 도입시켜, $1100^{\circ}C$의 초고온에서 개질반응을 수행하였다. $CH_4$의 경우 11.95 Vol.%에서 0 Vol.%로 거의 대부분 분해되었으며, $H_2$는 17.77 Vol.%에서 25.46 Vol.%로 약 65.8% 증가하는 결과를 나타냈다. 또한 수소 생성량은 평균 5 L/min kg-Biomass이었다. 냉가스 효율은 72.1%로서 나타나, 일반적으로 폐기물의 냉가스 효율인 약 50% 전후의 결과에 비하여 높은 효율을 보였다.

• Transactions of the Korean hydrogen and new energy society
• /
• v.7 no.2
• /
• pp.147-155
• /
• 1996

The aim of this study is the development of technologies of methanol production from carbon dioxide by catalytic hydrogenation. Experiments about carbon dioxide hydrogenation by catalyst mixed with CuO, ZnO, $Cr_2O_3$ and $Al_2O_3$ were conducted to find optimum catalyst and reaction condition. Reactions were carried out at atmospheric and high pressures between 200 to $350^{\circ}C$. High yield of methanol was obtained with $Cu/ZnO/Cr_2O/Cr_2O_3/Al_2O_3$ catalyst at $250^{\circ}C$ and above 30 atmospheric pressure. There was not any increament of hydrogenation reactivity for the catalysts which was made by the addition of Pd to $Cu/ZnO/Cr_2O/Cr_2O_3/Al_2O_3$.

• 한국신재생에너지학회:학술대회논문집
• /
• 2009.06a
• /
• pp.840-843
• /
• 2009

폐자동차의 최종처분 과정에서 발생하는 자동차 파쇄 폐기물(Automobile Shredder Dust)은 대부분이 고분자 화합물로 높은 발열량을 가지고 있다. 또한 할로겐족 원소가 포함된 난연성 고분자류가 많아 다이옥신의 생성 우려가 높은 고분자류와 다이옥신 생성의 촉매 역할을 할 수 있는 금속성분이 많이 함유되어 있어 가스화용융시스템에 적용하여 처리하기에 매우 적합한 폐기물이다. 본 연구에서는 ASR의 가스화 용융 시설에서 고농도 CO를 함유한 합성가스를 수성가스전환반응(Water Gas Shift reaction, WGS)을 이용하여 수소의 수율을 높이는 기술을 제시하였다. 가스화 용융 설비에서 배출되는 합성가스 조성을 기준으로 적합한 고정층 WGS 반응기를 설계하고, 고온 촉매(KATALCO 71-5M)와 저온 촉매(KATALCO 83-3X)를 사용하여 실험하였다. 수성가스 반응 후의 가스 조성은 온도가 상승할수록 일산화탄소가 줄어들고 이에 따라 수소와 이산화탄소 발생량이 증가 되어 고온 촉매를 사용했을 경우 일산화탄소 전환율 ($1-CO_{out}/CO_{in}$)은 55.6에서 95.8%까지 상승하였다. 동일한 온도조건에서는 촉매에 관계없이 $CO/H_2$가 감소할수록 전환율도 감소하는 경향을 보였지만 동일한 합성가스 조성에서 일산화탄소 전환율을 비교하면 저온 촉매가 고온 촉매보다 매우 우수함을 알 수 있었다.

• Journal of the Korean Electrochemical Society
• /
• v.21 no.1
• /
• pp.1-5
• /
• 2018

In this study, boron - doped carbon was prepared by reducing carbon dioxide ($CO_2$) at high temperature by using sodium borohydride ($NaBH_4$). The boron - doped carbon was coated on carbon felt and applied as an electrode for a vanadium redox battery cell. As a result of electrochemical performance evaluation, reversibility of carbon felt coated with boron doped carbon compared to pure carbon felt was improved by about 20% and charge transfer resistance was reduced by 60%. In the charge / discharge results, energy density and energy efficiency were improved by 21% and 12.4%, respectively. These results show that carbon produced by reduction of $CO_2$ can be used as electrode material for redox flow battery.

• Journal of Energy Engineering
• /
• v.22 no.4
• /
• pp.347-354
• /
• 2013

This study was carried out to examine different mole ratio of $H_2/CO_2$ and EBCT using the continuous system in the lab scale throughout biological methods with accumulated hydrogenotrophic methanogen that can convert $CO_2$ to $CH_4$. The experimental-based results with various gas mixtures of mole ratio of 4:1($H_2/CO_2$) and 5:1($H_2/CO_2$), $H_2$ was converted more than 99% conversion rate. In case of $CO_2$, 4:1($H_2/CO_2$) and 5:1($H_2/CO_2$) were $74.45{\pm}0.33%$, $95.8{\pm}10.7%$, respectively, in addition, the study was confirmed that the amount of $H_2$ was more needed than stoichiometric equations, where approach methods are empirical versus theoretical frameworks, for converting total $CO_2$. As such, we have noticed that $H_2$ was used for energy source of hydrogenotrophic methanogen for maintaining life. Regarding the results of the ratio of treatment by retention time, limitation of treatment capacity showed that $H_2$(99.9%) and $CO_2$(96.23%) at EBCT 3.3 hrs indicated stable conversion ratio, as well as appeared that methane production rate and $CO_2$ fixation rate were investigated $1.15{\pm}0.02m^3{\cdot}m^{-3}{\cdot}day^{-1}$ and $2.01{\pm}0.04kg{\cdot}m^{-3}{\cdot}day^{-1}$, respectively.

• Transactions of the KSME C: Technology and Education
• /
• v.3 no.4
• /
• pp.285-290
• /
• 2015

Oxy gasification was performed for the production of high quality syngas from the waste. $CO_2$ was used as reactant with $O_2$ for $CO_2$ gasification and greenhouse gas reduction. Therefore, gasification was performed at high temperature of $1000-1400^{\circ}C$. RPF was gasified in the thermobalance and 0.5 ton/day pilot plant gasifier. Weight variation with temperature and CO production by Boudouard reaction were studied for $CO_2$ gasification of RPF in thermobalance reactor. Syngas of high $H_2$ concentration was produced from oxy gasification in 0.5 ton/day pilot system, which showed appropriate $H_2$/CO ratio for the production of transport fuel and chemical products.