• Title/Summary/Keyword: CO2 Rate

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Effect of Pt-Co/C Cathode Catalyst on Electrochemical Durability of Membrane in PEMFC (PEMFC에서 Pt-Co/C Cathode 촉매가 고분자막의 전기화학적 내구성에 미치는 영향)

  • Sohyeong Oh;Dong Geun Yoo;Myoung Hwan Kim;Ji Young Park;Kwonpil Park
    • Korean Chemical Engineering Research
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    • v.61 no.2
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    • pp.189-195
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    • 2023
  • As a PEMFC (Polymer Exchange Membrane Fuel Cell) cathode catalyst, Pt-Co/C has recently been widely used because of its improved durability. In a fuel cell, electrodes and electrolytes have a close influence on each other in terms of performance and durability. The effect on the electrochemical durability of the electrolyte membrane when Pt-Co/C was replaced in the Pt/C electrode catalyst was studied. The durability of Pt-Co/C MEA (Membrane Electrode Assembly) was higher than that of Pt/C MEA in the electrochemical accelerated degradation process of PEMFC membrane. As a result of analyzing the FER (Fluorine Emission Rate) and hydrogen permeability, it was shown that the degradation rate of the membrane of Pt-Co/C MEA was lower than that of Pt/C MEA. In the OCV (Open Circuit Voltage) holding process, the rate of decrease of the active area of the Pt-Co/C electrode was lower than that of the Pt/C electrode, and the amount of Pt deposited on the membrane was smaller in Pt-Co/C MEA than in Pt/C MEA. Pt inside the polymer membrane deteriorates the membrane by generating radicals, so the degradation rate of the membrane of Pt/C MEA with a high Pt deposition rate was higher than Pt-Co/C MEA. When the Pt-Co/C catalyst was used, the electrode durability was improved, and the amount of Pt deposited on the membrane was also reduced, thereby improving the electrochemical durability of the membrane.

Effects of W Contents in Co Matrix of the Thermal Sprayed WC-Co on the Corrosion Behavior in Molten Zinc

  • Seong, Byeong-Geun;Hwang, Sun-Young;Kim, Kyoo-Young;Lee, Kee-Ahn
    • Corrosion Science and Technology
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    • v.6 no.4
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    • pp.147-153
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    • 2007
  • This study sought to investigate the reaction of Co-binder containing tungsten with molten zinc. Four kinds of Co-W alloys (pure, 10%W, 20%W, 30%W) were prepared using the powder metallurgy method. The specimens were immersion-tested in molten pure zinc baths at $460^{\circ}C$. To evaluate the corrosion property in molten zinc, the weight loss of the specimen was measured after the immersion tests at different immersion times (10~300 min.). Co-10%W alloys, compared with pure cobalt, showed no effect of tungsten addition on the reaction rate in molten zinc. The relationship between the weight loss and the square root of immersion period represents a straight line in both pure cobalt and Co-10%W alloy. The Co-Zn reaction layer in Co- 1O%W alloy consists of $\gamma2$, $\gamma1$, $\gamma$ and ($\beta1$ phases. The rate of weight loss significantly increases and the weight loss behavior is not well accord with the linear relationship as the tungsten content in the Co-W alloy increases. The $\beta1$ layer was not formed on the Co-20%W alloy and neither was a stable Co-Zn intermetallic compound layer found on the Co-30%W alloy. The main cause of increase in reaction rate with increasing tungsten content is related with the instability of the Co-Zn reaction phases as seen on micro-structural analysis.

Low Grade Coal-CO2 Catalytic Gasification Reaction for CO gas Synthesis (CO 합성을 위한 저급석탄-CO2 촉매 가스화 반응)

  • Lee, Ho Yong;Lee, Jong Dae
    • Journal of the Korean Applied Science and Technology
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    • v.33 no.3
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    • pp.466-473
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    • 2016
  • In this study, the experiments on optimal CO gas synthesis were conducted using low grade coal-$CO_2$ catalyst gasification reaction. The characteristics of generated CO gas were investigated using the chemical activation method of KOH, $K_2CO_3$, $Na_2CO_3$ catalysts with Kideco and Shewha coal. The preparation process has been optimized through the analysis of experimental variables such as ratio between activating chemical agents and coal, the flow rate of gas and reaction temperature during $CO_2$ conversion reaction. The produced CO gas was analysed by Gas Chromatography (GC). The 98.6% $CO_2$ conversion for Kideco coal mixed with 20 wt% $Na_2CO_3$ and 98.9% $CO_2$ conversion for Shenhua coal mixed with 20 wt% KOH were obtained at the conditions of $T=950^{\circ}C$ and $CO_2$ flow rate of 100 cc/min. Also, the low grade coal-$CO_2$ catalytic gasification reaction showed the CO selectivities(97.8 and 98.8 %) at the same feed ratio and reaction conditions.

Chemical Reaction of Carbon Dioxide with AMP in w/o Emulsion Membrane (W/O 에멀션액막에서 이산화탄소와 AMP의 화학반응)

  • Park Sang-Wook;Choi Byoung-Sik;Kim Seong-Soo;Lee Jae-Wook
    • Membrane Journal
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    • v.14 no.4
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    • pp.275-288
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    • 2004
  • Carbon dioxide was absorbed into water-in-oil (w/o) emulsion composed of aqueous 2-amino-2-methyl-1-propanol (AMP) droplets as a dispersed phase and benzene solutions of polybutene and polyisobutylene as a continuous phase in a flat-stirred vessel to investigate the effect of non-Newtonian rheological behavior on the rate of chemical absorption of $CO_2$, where the reaction between $CO_2$ and AMP in the aqueous phase was assumed to be a pseudo-first-order reaction. It was expressed that PIB with elastic property made the rate of chemical absorption of $CO_2$ accelerated by comparison of mass transfer coefficient of $CO_2$ in the non-Newtonian liquid with that in the Newtonian liquid.

Influence of carbonized crop residue on soil carbon storage in red pepper field

  • Lee, Jae-Ho;Eom, Ji-Young;Jeong, Seok-hee;Hong, Seung-Bum;Park, Eun-Jin;Lee, Jae-Seok
    • Journal of Ecology and Environment
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    • v.41 no.12
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    • pp.336-344
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    • 2017
  • Background: Because of climate change, interest in the development of carbon pools has increased. In agricultural ecosystems, which can be more intensively managed than forests, measures to control carbon dioxide ($CO_2$) emission and absorption levels can be applied relatively easily. However, crop residues may be released into the atmosphere by decomposition or combustion. If we can develop scientific management techniques that enable these residues to be stocked on farmland, then it would be possible to convert farmlands from carbon emission sources to carbon pools. We analyzed and investigated soil respiration (Rs) rate characteristics according to input of carbonized residue of red peppers (Capsicum annuum L.), a widely grown crop in Korea, as a technique for increasing farmland carbon stock. Results: Rs rate in the carbonized biomass (CB) section was $226.7mg\;CO_2\;m^{-2}h^{-1}$, which was 18.1% lower than the $276.9mg\;CO_2\;m^{-2}h^{-1}$ from the red pepper residue biomass (RB) section. The Rs rate of the control was $184.1mg\;CO_2\;m^{-2}h^{-1}$. In the following year, Rs in the CB section was $204.0mg\;CO_2\;m{-2}h^{-1}$, which was 38.2% lower than the $330.1mg\;CO_2\;m^{-2}h^{-1}$ from the RB section; the control emitted $198.6mg\;CO_2\;m^{-2}h^{-1}$. Correlation between Rs and soil temperature ((Ts) at a depth of 5 cm) was $R^2=0.51$ in the RB section, which was higher than the other experimental sections. A comparison of annual decomposition rates between RB and CB showed a large difference, 41.4 and 9.7%, respectively. The results showed that carbonization of red pepper residues reduced the rates of decomposition and Rs. Conclusions: The present study confirmed that the Rs rate can be reduced by carbonization of residue biomass and putting it in the soil and that the Rs rate and Ts (5 cm) were positively correlated. Based on the results, it was determined that approximately $1.2t\;C\;ha^{-1}$ were sequestered in the soil in the first year and $3.0t\;C\;ha^{-1}$ were stored the following year. Therefore, approximately $1.5t\;C\;ha^{-1}year^{-1}$ are expected to be stocked in the soil, making it possible to develop farmlands into carbon pools.

Study on Heat Transfer Characteristics of Internal Heat Exchanger for $CO_2$ Heat Pump under Heating Operating Condition (난방운전 조건하에서 $CO_2$ 열펌프용 내부 열교환기의 열전달 특성에 대한 연구)

  • Kim, Dae-Hoon;Lee, Sang-Jae;Choi, Jun-Young;Lee, Jae-Heon;Kwon, Young-Chul
    • Journal of Energy Engineering
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    • v.17 no.2
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    • pp.116-123
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    • 2008
  • In order to study the heat transfer, effectiveness and pressure drop of an internal heat exchanger (IHX) for $CO_2$, heat pump under heating condition, the experiment and numerical analysis were performed. Four kinds of IHXs were used. The section-by-section method and Hardy-Cross method were used for the numerical analysis. The effects of IHX on the flow rate of refrigerant, the IHX length, the operating condition of a gas-cooler and an evaporator and the type of IHXs were investigated. With increasing the flow rate, the heat transfer rate increased about 25%. The heat transfer of the micro-channel tube was larger about 100% than that of the coaxial tube. With increasing the IHX length, the heat transfer rate decreased. The low-side pressure drop was larger compared with that of the high-side. And the pressure drop of the microchannel tube was larger about 100% than that of the coaxial tube. With increasing the high-side temperature and decreasing the low-side temperature, the heat transfer rate increased about 3%. From this study, we can see that new correlation on $CO_2$ heat transfer characteristics and tube type is necessary.

Environmental Effect Analysis for PV system using LCA (LCA를 이용한 태양광발전의 환경영향분석)

  • Choi, Bong-Ha;Park, Soo-Uk;Lee, Deok-Ki
    • New & Renewable Energy
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    • v.3 no.2 s.10
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    • pp.11-16
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    • 2007
  • This paper analyses the environmental effect of 100kw PV system installed in Tibet using Life Cycle Assessment(LCA). Then, energy payback time(EPT) and life-cycle CO2 emission rate are estimated based on life-cycle of the PV system. As a result of the estimation, 6 year of EPT and 20 g-C/kWh of CO2 emission rate are obtained. In China, average CO2 emission rate of fossil fuel power generation plant is 260 g-C/kWh. This shows that PV system would be very promising for global environmental issues. For advanced LCA, we need to collect detailed and various data about raw material of PV system.

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Removal of CO2 in Syngas using Li2ZrO3 (Li2ZrO3를 이용한 합성가스내의 CO2 제거)

  • Park, Joo-Won;Kang, Dong-Hwan;Yoo, Kyung-Seun;Lee, Jae-Goo;Kim, Jae-Ho;Han, Choon
    • Applied Chemistry for Engineering
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    • v.17 no.3
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    • pp.250-254
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    • 2006
  • Reaction of $CO_2$ with $Li_{2}ZrO_{3}$ has been investigated in a TGA and the effects of $H_{2}$ and CO on the removal of $CO_{2}$ using $Li_{2}ZrO_{3}$ were evaluated in a packed bed reactor. The initial rate of $CO_{2}$ removal reaction of $Li_{2}ZrO_{3}$ increased with the increase of gas flow rate up to 100 mL/min and then was maintained, which implied the disappearance of the gas film resistance. The reaction of $CO_{2}$ with $Li_{2}ZrO_{3}$ took place as the first order and the range of optimum temperature was found to be about $500{\sim}600^{\circ}C$. XRD and SEM analysis showed the formation of crystalline $Li_{2}ZrO_{3}$ and porous $Li_{2}ZrO_{3}$/$ZrO_{2}$. The presence of $H_{2}$ did not affect the adsorption of $CO_2$ with $Li_2ZrO_3$. On the other hand, CO inhibited the sorption of $CO_{2}$ into $Li_{2}CO_{3}$(L) on $Li_{2}ZrO_{3}$.

Studies on th Effects of Co-Culture with Cumulus Cells, Oviduct Epithelial Cells and Uterine Endometrial Cells on In Vitro Fertilization and Cleavage Rate of Bovine Oocytes (난구, 난관 상피세포 및 자궁 내막세포와의 공동배양이 소 난포란의 체외수정 및 분할율에 미치는 영향에 관한 연구)

  • ;Y. Hukui
    • Korean Journal of Animal Reproduction
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    • v.17 no.2
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    • pp.141-148
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    • 1993
  • This studies were carried out to investigate the effects of co-culture with cumulus cells, oviduct epithelial cells and uterine endometrium cells on the in-vitro fertilization and cleavage rate of bovine follicular oocytes. The ovaries were obtained from slaughtered Korean native cows. The follicular oocytes surrounded with cumulus cells were recovered by aspirating follicular fluids from the visible follicles of diameter 3~5 mm. The follicular oocytes were cultured in TCM-199 medium containing hormones and 10% FCS for 24~48 hrs in a incubator with 5% CO2 in air at 38.5$^{\circ}C$ and then matured oocytes were again cultured for 12~18 hrs with motile capacitated sperm by preincubation. The results obtained in these experiments were summarized as follows: 1. The in vitro maturatin and fertilization rate of bovine oocytes co-cultured with cumulus cells in TCM-199 medium were 64.0~74.1% and 40.0~58.6% respectively. And in-vitro fertilization rate of cumulus-enclosed oocytes(55.4%) were significantly(p<0.05) higher than cumulus-denuded oocytes(23.1%). 2. The in-vitro maturatin and fertilization rate of bovine oocytes co-cultured with 1$\times$104 cells/ml, 1$\times$106 cells/ml, 1$\times$108 cells/ml and 1$\times$1015 cells/ml oviduct epithelial cells in TCM-199 medium were 59.3% and 40.7%, 64.0% and 48.0%, 58.3% and 37.5%, 52.0% and 32.0%, respectively. 3. The in-vitro maturation and fertilization rate of bovine oocytes co-cultured with 1$\times$104 cells/ml, 1$\times$106 cells/ml, 1$\times$108 cells/ml and 1$\times$1015 cells/ml uterine endometrium cells in TCM-199 medium were 56.0% and 36.0%, 60.7% and 42.9%, 59.3% and 37.0%, 52.0% and 36.0%, respectively. 4. When the in-vitro fertilized oocytes were co-cultured with cumulus cells, oviduct epithelial cells and uterine endometrium cells, the development rate to be blastocyst was 12.2%, 15.6% and 11.7%, respectively and rates were higher than that of control, 2.1%(P<0.05).

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공동주책의 에너지소비와 이산화탄소 배출특성

  • 이윤규;이강희
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.9
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    • pp.868-877
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    • 2001
  • This study is to present the typical energy consumption criteria and $CO_2$ exhaust rate in multi-family housing complex by analyzing the energy consumption characteristics. The contents and methodology of this study are as follows; -Examining the documents of maintenance accounts, investigate the cost and its items expended by the annual maintenance in multi-family housing complex. -Survey each consumption of energy sources, maintenance area, location of multi-family housing complex, heating type, and so forth. -After classifying with heating type of multi-family housing complex investigated, Scrutinize the energy consumption by each source. -Analyze the characteristics of energy consumption and $CO_2$ exhaust through multiple regression analyses of maintenance property. -Suggest the typical energy consumption criteria (Mcal/$m^2$.year, Mcal/house.year) and $CO_2$ exhaust rate (kg-c/$m^2$.year, Kg-c/house.year) in multi-family housing complex. the results will come into basic data for estimating energy consumption in multi-family housing complex according to maintenance characteristics.

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