• Journal of Environmental Science International
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• v.15 no.3
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• pp.211-219
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• 2006

An experimental study on the removal of VOCs gas using a biomembrane reactor were carried out at various inlet gas concentration, specific loading rate, retention time and gas flow rate of volume. The variations of efficiency and various parameters, which are relevant to gas removal, with mixing of soluble gas and without have been discussed. More than 95% of the toluene and methanol present in the feed was successfully removed in each study. The elimination of methanol with mixture of soluble compound of about 300 mg/h corresponds to a portion of 21% if there is a feed stream of 1400 mg/h. On the contrary the maximum efficiency of about 72% of toluene was reached. This is to be rated as a treatment of sorption that the limiting factor of the dismantling speed could be represented by this difficult degradable component. Nevertheless the elimination capacities for this reactor for toluene were on a very high level. For substances which show a very high solubility in silicon rubber an advantage of a bio membrane is clearly shown. Therefore a similarly good result is expected for n-hexane, because of its relatively good permeability which was distinguished during permeation experiments.

• Macromolecular Research
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• v.15 no.6
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• pp.565-574
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• 2007

In this study, five representative, commercially available polymers, Ultem 1000 polyetherimide, Kapton polyimide, phenolic resin, polyacrylonitrile and cellulose acetate, were used to prepare pyrolyzed polymer membranes coated on a porous {\alpha}-alumina$ tube via inert pyrolysis for gas separation. Pyrolysis conditions (i.e., final temperature and thermal dwell time) of each polymer were determined using a thermogravimetric method coupled with real-time mass spectroscopy. The surface area and pore size distribution of the pyrolyzed materials derived from the polymers were estimated from the nitrogen adsorption/desorption isotherms. Pyrolyzed membranes from polymer precursors exhibited type I sorption behavior except cellulose acetate (type IV). The gas permeation of the carbon/{\alpha}-alumina$ tubular membranes was characterized using four gases: helium, carbon dioxide, oxygen and nitrogen. The polyetherimide, polyimide, and phenolic resin pyrolyzed polymer membranes showed typical molecular sieving gas permeation behavior, while membranes from polyacrylonitrile and cellulose acetate exhibited intermediate behavior between Knudsen diffusion and molecular sieving. Pyrolyzed membranes with molecular sieving behavior (e.g., polyetherimide, polyimide, and phenolic resin) had a $CO_2/N_2$ selectivity of greater than 15; however, the membranes from polyacrylonitrile and cellulose acetate with intermediate gas transport behavior had a selectivity slightly greater than unity due to their large pore size.

• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.333-338
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• 2015

In this study, we investigated carbonation-regeneration and agglomeration characteristics of dry sorbents. Experiment has been proceeded in the batch-type reactor, which is made of quartz: 0.05 m of I.D and 0.8 m in height. The sorbents that is collected at the cyclone of the carbonation reactor of continuous process were used in this study. The reactivity was studied at the various concentrations of water vapor, $N_2$ and $CO_2$ in the fluidizing gas at regeneration reaction. As a result, the reactivity increased as the regeneration temperature increased, the reactivity decreased as the concentration of water vapor increased. The absorption capacity showed the highest value in case of using $N_2$ 100% as regeneration gas. And decreased in order of $H_2O+N_2$, $CO_2$ 100% and $H_2O+CO_2$. The agglomeration characteristics were investigated according to the particle sizes and concentrations of water vapor at carbonation reaction. As a result, the particle with smaller size and higher concentration of water vapor showed the higher agglomeration characteristic.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.05a
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• pp.79-83
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• 2003

• Proceedings of the Membrane Society of Korea Conference
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• 1991.10a
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• pp.37-38
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• 1991

몇가지 dianhydride와 diamine을 사용하여 합성한 PAA막을 가열온도와 가열시간을 달리하여 이미드화를 달리하는 막을 제조하고 이압법에 의하여 투과계수와 확산계수를 측정하였다. 이로부터 얻은 흡수계수는 Dual-Mode Sorption Model에 의하여 상관시켰다. 이로부터 polyimide막에 있어서 이미드화에 따른 기체루과 특성과 화학구조에 의한 기체투과 특성의 일부를 규명하였다.

• Clean Technology
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• v.19 no.2
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• pp.165-172
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• 2013

In this study, the hydrogen chloride removal using K-based dry sorbents ($K_2CO_3/Al_2O_3$, KEPRI, Korea) was studied with varying the pressure in a fixed bed reactor (15 cm tall bed with 0.5 cm I.d.). Working temperature was $400^{\circ}C$ and feed gas concentration was 750 ppm (HCl vol%, $N_2$ balance). The chloride sorption capacity of sorbent increases with increasing pressure (1, 5, 10, 15 and 20 bar). Also, after forming KCl crystal by reaction with $K_2CO_3$ and HCl, owing to the strong bonding energy, sorbent regeneration was practically impossible. Its optical, physical and chemical characterizations were evaluated by SEM, EDAX, BET, TGA and XRD. At $400^{\circ}C$ and 20 bar condition, working condition for the dehalogenation process after gasification, K-based dry sorbent showed high HCl sorption capacity and HCl/$N_2$ separation performances comparing with Ca-based and Mg-based dry sorbents.

• Bulletin of the Korean Chemical Society
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• v.19 no.10
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• pp.1095-1099
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• 1998

The crystal structure of an acetylene sorption complex of dehydrated fully Mn(Ⅱ)-exchanged zeolite X, Mn46Si100Al92O384·30C2H2 (a=24.705(3) Å) has been determined by single-crystal X-ray diffraction techniques. The structure was solved and refined in the cubic space group Fd3 at 21(l) ℃. The complex was prepared by dehydration at 380 ℃ and 2 x 10-6 Torr for 2 days, followed by exposure to 300 Torr of acetylene gas for 2 h at 24 ℃. The structure was refined to the final error indices, R1=0.060 and R2=0.054 with 383 reflections for which I > 3σ(Ⅰ). In the structure, Mn2+ ions are located at two different crystallographic sites; sixteen Mn2+ ions at site I are located at the centers of the double six rings and thirty Mn2+ ions are found at site Ⅱ in the supercage, respectively. Each of these latter Mn2+ ions is recessed ca. 0.385(2) Å into the supercage from its three-oxygen plane. Thirty acetylene molecules are sorbed per unit cell. Each Mn2+ ion at site Ⅱ lies on a threefold axis in the supercage of the unit cell, close to three equivalent trigonally arranged zeolite framework oxygen atoms (Mn(Ⅱ)-O=2.135(9) Å) and symmetrically to both carbon atoms of a C2H2 molecules. At these latter distances, the Mn(Ⅱ)-C interactions are weak (Mn(Ⅱ)-C=2.70(5) Å), probably resulting from electrostatic attractions between the divalent cations and the polarizable π-electron density of the acetylene molecules.

• Journal of Hydrogen and New Energy
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• v.17 no.4
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• pp.434-439
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• 2006

In this study, activated carbon(ACs) have been modified by nitric acid and heat-treatment. The surface and structure properties of ACs were determined by BET surface area, FT-IR pH and acid/base value. The changes in pore structure and surface properties of these modified ACs were correlated with natural gas adsorption which measured by volumetric apparatus at $0^{\circ}C$ and $25^{\circ}C$. The pore textural properties of activated carbon was also characterized by nitrogen adsorption at 77 K. Specific surface area and micropore volume of them were calculated by Langmuir equation and Horvath-Kawazoe method, and chemical properties of surface were measured by FT-IR and titration of acid and base solutions. Pore texture of activated carbons after treatments were not significantly changed. Total acidity increased and basicity of samples decreased. however the basicity increased with heat treatment. The methane adsorption of ACs become different depending on the acid/base value of samples.

• Food Science and Preservation
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• v.5 no.3
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• pp.239-246
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• 1998

Polyimide membrane system was designed for manufacturing nitrogen-enriched gas, and basic technical data was suggested for appling this system to controlled atmosphere storage. The permeability characteristics of pure oxygen and nitrogen could be explained by dual-mode sorption model. There was substantial decrease in the permeation rates of oxygen, which is the more permeable gas, through the polyimide membrane due to the presence of nitrogen in comparison with pure oxygen. However, the permeation rates of nitrogen was increased by the presence of oxygen. The ideal separation factor was in the range of 5 to 6 in the range of temperature and pressure difference studied, and the separation factor of air was lower than the ideal separation factor. The increase of ideal separation factor with increasing temperature is due to the fact that the activation energy for oxygen is larger than that for nitrogen. Nitrogen concentration decreased rapidly with increasing product recovery, and it was found that this is a major operating factor to obtain nitrogen concentration required for controlled atmosphere storage. A relation equation, by which nitrogen concentration in storehouse can be predicted, was suggested under the establishment of a hypothetical model for controlled atmosphere storage process using polyimide membrane system.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.115-120
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• 2015

$K_2CO_3$-based dry regenerable sorbents were prepared by spray-drying techniques to improve mass produced $K_2CO_3-Al_2O_3$ sorbents (KEP-CO2P, hereafter), and then tested for their $CO_2$ sorption capacity by a $2,000Nm^3/h$ (0.5 MWe) $CO_2$ capture pilot plant built for Unit 3 of the Hadong thermal power station in 2010. Each of the sample sorbents contained 35 wt.% $K_2CO_3$ as the active materials with various support materials such as $TiO_2$, MgO, Zeolite 13X, $Al_2O_3$, $SiO_2$ and hydrotalcite (HTC). Their physical properties and reactivity were tested to evaluate their applicability to a fluidized-bed or fast transport-bed $CO_2$ capture process. The $CO_2$ sorption capacity and percentage utilization of $K_2CO_3$-MgO based sorbent, Sorb-KM2, was $8.6g-CO_2/100g$-sorbents and 90%, respectively, along with good mechanical strength for fluidized-bed application. Sorbs-KM2 and KT were almost completely regenerated at $140^{\circ}C$. No degradation of Sorb-KM by $SO_2$ added as a pollutant in flue gas was observed during a cycle test.