• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.947-953
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• 2017

In this study, the regeneration efficiency of the amino acid salt absorbent which can be applied to carbon dioxide absorption / regeneration process was confirmed. The regeneration efficiency has a great influence on the economical judgment of the process. so, continuous regeneration experiment was conducted to establish economical process. The amino acid salts used in the experiments are Potassium L-lysinate and Potassium L-alaninate. Each amino acid and potassium hydroxide(KOH) were mixed at a 1: 2 molar ratio. In order to confirm the regeneration efficiency of the absorbent, carbon dioxide was absorbed in the two materials, and the carbon dioxide desorption experiment was carried out by heating. The initial reaction rate was L-alanine was faster. Over time, L-lysine, desorption higher concentrations of carbon dioxide. L-lysine showed higher regeneration efficiency than L-alanine, (L-alanine 47.26% and L-lysine 62.11%). As a result of the continuous regeneration experiment using the L-lysine having good absorption and regeneration efficiency, it was confirmed that the regeneration efficiency decreases as the number of regeneration increases.

• Spatial Information Research
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• v.20 no.5
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• pp.1-13
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• 2012

This study intends to evaluate the seasonal flow direction of carbon dioxide in Northeast Asia by using GOSAT, the first Greenhouse Observing SATellite, in an attempt to overcome costly, laborious and time consuming ground observation which has been frequently pointed out in existing studies. For this purpose, missing values were supplemented by applying the Kriging interpolation and the overall flow direction of carbon dioxide was determined through anisotoropy semi-variogram. As a result, it was found that the overall spatial distribution of carbon dioxide in Northeast Asia varies depending on the latitude, and that carbon dioxide mainly flows southeast or east in spring, autumn and winter, but northeast or north in summer. Similar to the flow of monsoons in Northeast Asia, these results show that carbon dioxide flows mainly from the west to the east, which proves that carbon dioxide discharged from China is influencing even the Korean Peninsula and Japan. However, as the flow of carbon dioxide varies depending on a variety of factors such as artificial sources, plant respiration, and the absorption and discharge of the ocean, follow-up studies are requested to evaluate such variables and the correlations.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.1
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• pp.157-164
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• 2021

Wind and temperature were measured with a three-dimensional ultrasonic anemometer and the carbon dioxide concentration was measured using an infrared sensor in the tidal flat of Suncheon Bay. In general, as the temperature increases, the concentration of carbon dioxide increases, and as the temperature decreases, the carbon dioxide also decreases in the atmosphere. However, since photosynthesis declined immediately after the sunset, the concentration of carbon dioxide increased as the temperature decreased. In addition, near the high tide when the tidal flat is covered with seawater, the atmospheric turbulence was strong despite an increase in temperature, resulting in a decrease in carbon dioxide concentration. It is necessary to quantitatively evaluated the effects of photosynthesis, respiration and atmospheric turbulence on the change of carbon dioxide concentration over tidal flat ecosystems.

• International Journal of Air-Conditioning and Refrigeration
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• v.14 no.1
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• pp.19-27
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• 2006

The characteristics of heat transfer and pressure drop have been investigated experimentally during gas-cooling process of carbon dioxide. The results of this study are useful information in the design of a heat exchanger of $CO_2$ refrigerator. The test section consists of 6 series of copper tube, 4.15 and 2.18mm ID, respectively. The inlet temperature, the operating pressure, and the mass flux are varied in the range of $80{\sim}120^{\circ}C,\;{7\sim}10MPa,\;and\;400{\sim}1,900kg/m^2s$, respectively. The heat transfer coefficient of $CO_2$ is affected by temperature, inlet pressure, and mass flux of $CO_2$. At the maximum HTC, the temperature of $CO_2$ nearly accords with the psuedocritical temperature. It is found that the pressure drop is substantially affected by mass flux and inlet pressure of $CO_2$ . The results have been compared with those of previous work. The heat transfer correlation at the gas-cooling process has been also suggested which predicts within the error of 20%.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.783-787
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• 2013

The separation and capture process of carbon dioxide from power plants is garnering interest as a method to reduce greenhouse gas emissions. In this study, aqueous alkanolamine solutions were studied as absorbents for $CO_2$ capture. The solubility of $CO_2$ in aqueous alkanolamine solutions was investigated with a continuous stirred reactor at 313, 333 and 353 K. Also, the heat of absorption ($-{\Delta}H_{abs}$) between the absorbent and $CO_2$ molecules was measured with a differential reaction calorimeter (DRC) at 298 K. The solubility and heat of absorption were determined at slightly higher than atmospheric pressure. The enthalpies of $CO_2$ absorption in monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), and 2-amino-2-methyl-1-propanol (AMP) were 88.91, 70.44, 44.72, and 63.95, respectively. This investigation showed that the heat of absorption is directly related to the quantity of heat for absorbent regeneration, and is dependent on amine type and $CO_2$ loading.

• Journal of the Korean Applied Science and Technology
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• v.15 no.2
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• pp.67-75
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• 1998

The Cuo-Magnetite and ZnO-Magnetite catalysts with various of Cuo and ZnO mole% for Carbon Dioxide decomposed reaction synthesized. The catalysts were reduced by $H_2$ at $350^{\circ}C$ for 3 hours. The temperature was obtained by TGA and DSC experiments. The structures of catalysts were confirmed by X-ray diffraction experiment. The surface area of catalysts is $15{\sim}27\;m^2/g$. The results of Carbon Dioxide decomposed ability was better $H_2-reduced$ magnetite catalysts with 0.03 mole% CuO and 0.03 mole% ZnO than others catalysts. After Carbon Dioxide decomposed reaction, catalysts were reacted $H_2$ and created only methane.

• Applied Chemistry for Engineering
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• v.9 no.6
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• pp.924-929
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• 1998

In this work, high pressure binary phase equilibria data of carbon dioxide with acetonitrile and acrylonitrile were obtained experimentally. A new static type experimental apparatus was built to measure temperature, pressure and phase equilibria composition. The accuracy of the experimental apparatus was tested by comparing the measured phase equilibria data of the carbon dioxide-acetonitrile system at $75^{\circ}C$ with those of McHugh and coworkers. The binary phase behavior data of carbon dioxide-acetonitirle system were measured from 2.4 to 14.5 MPa at $55^{\circ}C$, $75^{\circ}C$ and $100^{\circ}C$. Also, the phase equilibria of the system carbon dioxide-acrylonitrile were measured from 1.6 MPa up to 13.9 MPa at $45^{\circ}C$, $65^{\circ}C$, $85^{\circ}C$ and $105^{\circ}C$. The solubility of acetonitrile and acrylonitrile increases as the temperatures increases at constant pressure. Also, these two carbon dioxide-polar solute system have continuous critical-mixture curves that exhibit maximums in pressure at temperatures between the critical temperatures of carbon dioxide and acetonitrile or acrylonitrile. The experimental data obtained in this study were modeled using the Peng-Robinson equation of state. Good agreement between calculated and experimental results was observed.

• Environmental Engineering Research
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• v.19 no.3
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• pp.289-292
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• 2014

The effect of carbon dioxide ($CO_2$) on global warming is serious problem. The adsorption with solid sorbents is one of the most appropriate options. In this study, the most interesting adsorbent is granular activated carbon (GAC). It is suitable material for $CO_2$ adsorption because of its simple availability, many specific surface area, and low-cost material. Afterwards, GAC was impregnated with chitosan solution as impregnated granular activated carbon (CGAC) in order to improve the adsorption capacity of GAC. This research aims to compare the physical and chemical characteristics of GAC and CGAC. The experiment was carried out to evaluate the efficiency of $CO_2$ adsorption between GAC and CGAC. The results indicated that the iodine number of GAC and CGAC was 137.17 and 120.30 mg/g, respectively. The Brunauer-Emmett-Teller results (BET) of both GAC and CGAC show that specific surface area was 301.9 and $531.3m^2/g$, respectively; total pore volume was 0.16 and $0.29cm^3/g$, respectively; and mean diameter of pore was 2.18 and 2.15 nm, respectively. Finally, the $CO_2$ adsorption results of both GAC and CGAC in single column how the maximum adsorption capacity was 0.17 and 0.25 mol/kg, respectively; how degeneration time was 49.6 and 80.0 min, respectively; and how the highest efficiency of $CO_2$ adsorption was 91.92% and 91.19%, respectively.

• Journal of the Korean GEO-environmental Society
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• v.23 no.12
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• pp.55-61
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• 2022

Carbon dioxide is one of the greenhouse gases in the atmosphere and much research is underperforming in reducing carbon dioxide. Geological carbon dioxide storage is considered the primary technique for global warming prevention. So, technic development for storing carbon dioxide is required. Using surfactant is considered an effective material for geological carbon dioxide storage. However, research on using surfactants for carbon dioxide sequestration is not enough. In this study, a 2D micromodel experiment depends on the surfactant type (sodium dodecyl sulfate and sodium dodecylbenzene sulfonate), concentration and carbon dioxide injection rate. As result, geological carbon dioxide sequestration efficiency is increased according to surfactant concentration and carbon dioxide injection rate increase. However, efficiency no more increases after critical concentration and rate.

• Journal of Soil and Groundwater Environment
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• v.27 no.2
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• pp.41-49
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• 2022

To abate the environmental burdens arising from CO₂ emissions, biochar offers a strategic means to sequester carbons due to its recalcitrant nature. Also, biochar has a great potential for the use as carbon-based adsorbent because it is a porous material. As such, developing the surface properties of biochar increases a chance to produce biochar with great adsorption performance. Given that biochar is a byproduct in biomass pyrolysis, characteristics of biochar are contingent on pyrolysis operating parameters. In this respect, this work focused on the investigation of surface properties of biochar by controlling temperature and reaction medium in pyrolysis of pine sawdust as case study. In particular, CO₂ was used as reaction medium in pyrolysis process. According to pyrolytic temperature, the surface properties of biochar were indeed developed by CO₂. The biochar engineered by CO₂ showed the improved capability on CO₂ sorption. In addition, CO₂ has an effect on energy recovery by enhancing syngas production. Thus, this study offers the functionality of CO₂ for converting biomass into engineered biochar as carbon-based adsorbent for CO₂ sorption while recovering energy as syngas.