• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.244-250
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• 2012

In order to separate of carbon dioxide in the combustion exhaust gas, monoethanolamine (MEA) and piperazine (PZ) impregnated zeolite 13X adsorbents were used. A series of adsorbents were synthesized by impregnating 30, 50 and 70 wt% of MEA and PZ respectively on zeolite 13X pellet. XRD, FT-IR and BET were used to characterize the properties of impregnated pelletized zeolite 13X absorbents. In order to investigate the separation characteristics of carbon dioxide, zeolite pellet, MEA impregnated zeolite and PZ impregnated zeolite pellet were investigated at 25, 50 and $75^{\circ}C$. Amine impregnated pelletized zeolite absorbent has shown that adsorption decreases with increasing temperature. Finally, the carbon dioxide adsorption capacity when emission temperature of the combustion exhaust gas, PZ impregnated zeolite pellet was 1.8 times than zeolite pellet as well as 20 times than MEA impregnated zeolite pellet.

• Proceedings of the Membrane Society of Korea Conference
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• 1995.09a
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• pp.73-85
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• 1995

The asymmetric hollow fiber membranes were prepared by the wet spining of polyetherimide dope solution and the effect of hollow fiber structures on the permeation characteristics of carbon dioxide and nitrogen gases through these membrane were investigated. As the concentration of the $\gamma$-butyrolactone (GBL) in dope solution, acting as a swelling agent was increased, the structure of hollow fiber was changed from the finger to sponge type. The permeabilities of gases (CO$_{2}$, N$_{2}$) through these membrane were measured over the wide range of pressure under different temperature. The effect of water vapor on the permeabilities of gases was also investigated. The measured permeabilities showed the different characteristics depending on the structure of membranes. It was found that the flow through the pores were dominant over the polymers matrix. Blocking effect by water vapor in the pores of skin layer greatly improved the ideal separation factor of carbon dioxide/nitrogen.

• Applied Chemistry for Engineering
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• v.7 no.4
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• pp.605-613
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• 1996

The permeation characteristics were investigated for pure carbon dioxide and methane through asymmetric cellulose acetate(CA) membrane, composite cellulose acetate membrane and asymmetric cellulose triacetate(CTA) membrane. In particular, the effect of operating pressure on the permeation performance was examined. And the permeation behavior for a mixture of carbon dioxide and methane ($CO_2/CH_4=57.6/42.4$) was also investigated and compared to the characteristics obtained from pure gases. The experiments were run at the range of partial pressure from 25 to 125 psig, and room temperature. The permeation behaviors of the CA composite and CTA membrane were similiar to those of the CA membrane. The permeation rates of pure carbon dioxide for CA, CA composite and CTA membrane were increased slightly with an increase in upstream partial pressure, while in the case of pure methane they were independent of upstream partial pressure. For a binary mixture of carbon dioxide and methane, abnormal permeation behaviors were observed due to the plasticization of carbon dioxide and the competition effect of each gas. The separation factor and permeation rate for CTA membrane were found to be higher than those for CA membrane, but the mechanical strength of CTA membrane was very poor. And the permeation rate for CA composite membrane was higher than that for CA membrane. Consequently, it can be said that the CA composite membrane is a strong candidate for the separation of $CH_4$ and $CO_2$.

• Membrane Journal
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• v.32 no.4
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• pp.218-226
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• 2022

Hydrogen, a carrier of large-capacity chemical and clean energy, is an important industrial gas widely used in the petrochemical industry and fuel cells. In particular, hydrogen is mainly produced from fossil fuels through steam reforming and gasification, and carbon dioxide is generated as a by-product. Therefore, in order to obtain high-purity hydrogen, carbon dioxide should be removed. This review focused on free-standing polymeric membranes and mixed-matrix membranes (MMMs) that separate hydrogen from carbon dioxide reported in units of Barrer [1 Barrer = 10^-10 cm³ (STP) × cm / (cm² × s × cmHg)]. By analyzing various recently reported papers, the structure, morphology, interaction, and preparation method of the membranes are discussed, and the structure-property relationship is understood to help find better membrane materials in the future. Robeson's upper bound limits for hydrogen/carbon dioxide separation were presented through reviewing the performance and characteristics of various separation membranes, and various MMMs that improve separation properties using technologies such as crosslinking, blending and heat treatment were discussed.

• Membrane Journal
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• v.25 no.3
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• pp.248-255
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• 2015

Aminated polyetherimide membrane synthesized in the laboratory according to amine ratio was used for measurement of gas permeability, diffusivity, and solubility about carbon dioxide, nitrogen, methane, oxygen, and sulfur dioxide with Time-lag method at room temperature. Generally, gas permeability is totally decreased because the more amination rate reacted to the main chain of amine groups, the more intermolecular space became narrow. However, gas permeability of sulfur dioxide was increased due to combination of sulfur dioxide and amine groups have acid and base properties respectively. Diffusivity and solubility of dry gas are totally decreased excluding sulfur dioxide as increasing amination rate. In case of sulfur dioxide, however, diffusivity as well as solubility was increased as increasing amination rate. Selectivity of carbon dioxide/nitrogen showed 60 when amination rate was 3. In case of humid gas, gas permeability of carbon dioxide was 70 barrer when relative humidity showed 100, and selectivity with nitrogen approximately showed 18.

• Applied Chemistry for Engineering
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• v.20 no.1
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• pp.104-108
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• 2009

In this study, for the flow of carbon dioxide/hydrogen mixture through a tubular type Pd-Ag membrane, hydrogen partial pressure, velocity profile, and concentration profile were simulated as a function of inlet flow rate using computational fluid dynamics (CFD) technique. The simulation results indicated that the mole fraction of carbon dioxide increased slowly in the longitudinal direction as the flow rate increased. In addition, the effects of inlet flow rate and the length of membrane on hydrogen recovery were investigated. At lower flow rate and for longer membrane, the hydrogen recovery was larger.

• Proceedings of the Membrane Society of Korea Conference
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• 1999.07a
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• pp.48-51
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• 1999

To investigate numerically the removal behavior of carbon dioxide in a hollow fiber membrane contactor, the system controlling equations were developed including the nonlinear reversible reaction terms. The reversible chemical reactions were incorporated in the system controlling equations, resulting in the coupled nonlinear partial differential equations which could describe either the absorption of the desorption of carbon dioxide. The computer program was coded using the Fortran language and run with a personal computer to find out the effects of the system variables: the pressures of absorbed and desorbed gases, the absorbent flow rate, the concentration of potassium carbonate, the fiber diameter and the length.

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.489-492
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• 2011

Supercritical fluid technology has been an alternative for purification and separation of biological compounds in cosmetic, food, and pharmaceutical products. Solubility information of biological compounds in supercritical fluids is essential for choosing a supercritical fluid processes. The equilibrium solubility of hinokitiol was measured in supercritical carbon dioxide with a static method in the pressure range from 8 to 40 MPa and at temperatures equal to 313.2, 323.2 and 333.2 K. The experimental data were correlated well by Peng.Robinson equation of state and quasi-chemical nonrandom lattice fluid model.

• Proceedings of the Membrane Society of Korea Conference
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• 1999.07a
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• pp.108-110
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• 1999

• Membrane Journal
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• v.10 no.1
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• pp.39-46
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• 2000

To predict the absorption behavior of carbon dioxide on membrane contactor, an aqueous potassium carbonate solution as an absorbent. The reversible reactions of carbon dioxide with chemicals were considered, and the physicochemical properties of reaction rate constants, equilibrium constants, solubilities and diffusion coefficients were used as a function of concentration of carbon dioxide and the temperature. A non-wetted mode was also used as an operating condition of the membrane contactor. In these operation conditions, the effect of the following system parameters were studied : the concentration of potassium carbonate, the velocity of the absorbent and the pressure of the mixture gas. The absorption behavior of carbon dioxide caused by a facilitated transport was observed as the increment of the concentration of the absorbent. The absorption rate of carbon dioxide was increased as the absorbent velocity was increased. Furthermore, it was found that the pressure if the mixture gas and the reuse number of absorbent affect severely the absorption rate of carbon dioxide. The absorption behavior was successfully predicted by the computer simulation using the system parameters which are important for design and operation of the membrane contactor.