• Membrane Journal
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• v.2 no.2
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• pp.135-143
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• 1992

Separation of $N_2-SO_2$ mixed gas by polymer membranes, SEPA-97(CA), TFC, and FT-30 membrane, was investigated by varying pressure and temperature. The permeability coefficients and the separation factors of mixed gases were measured, and the influence of various factors on the gas permeability characteristics and separation performance were investigated. The range of pressure was 0.1~1.0 MPa, and that of temperature was 283~303 K. The experimental results showed that the permeability coefficients and the separation factors were increased with an increase in pressure, but they were deereased with increasing temperature. Among the examined membranes, FT-30 possessed the best gas-separating characteristics.

• Membrane Journal
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• v.15 no.2
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• pp.141-146
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• 2005

In this study, carbon composites were prepared using carbon graphite, thermoset resin, and carbon black. Oxygen permeability was measured using the continuous flow gas permeation analyzer as a function of composition and processing conditions. The experimental results showed that the oxygen permeability increased as the carbon black content increased, whereas the oxygen permeability decreased as the pressing time increased. The oxygen permeability was not affected by the processing pressure.

• Archives of Pharmacal Research
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• v.3 no.2
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• pp.65-74
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• 1980

Analysis of particle size distribution of a sample of fine aluminum hydroxide powder was carried out by four different methods, i. e., conductivity, air permeability, gas-adsorption and sedimentation. Each method was reproducible. The results obtained by Coulter counter and sedimentation balance were similar, and the data obtained by Lea and Nurse permeameter and Stroehlein areameter were also similar. But the results differ considerabley between the former and the latter. The advantages and disavantages of each method were discussed briefly and a means of comparing the results with those obtianed by surface area measurements was shown.

• Journal of Sensor Science and Technology
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• v.21 no.3
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• pp.229-234
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• 2012

The existing permeability measurements based on pressure differential between the polymer membrane that is permeable to measure the amount of oxygen used, but these methods must be kept in a vacuum, and the measurement of the membrane with low permeability in the membrane is too time consuming. In recent years by using electrochemical method polymer membrane currents caused by the amount of oxygen is a measure of how much is used. In this study, apparatus consisting of one anode and six cathodes for multi-oxygen permeability tester used the same number of membranes produced by electrochemical oxygen permeation characteristics. In this study, one silver/silver chloride anode electrochemical method with a hexagonal sensor to put various kinds of polymer membranes with the six oxygen permeability for simultaneous measurement in real-time systems. Six cathodes (Pt), and one of the coil-shaped anode (Ag/AgCl) to form a hexagonal one of the polarographic oxygen sensor in a single measurement system by six sensors. Each sensor for making hexagonal specificity of the sensor to compensate for the conditions obtained in a pure nitrogen gas and pure oxygen gas conditions. With this study, self-developed hexagonal sensor capable of measuring sensors and oxygen permeability tester, for a multi-six different oxygen permeability characteristics of the membrane measured at the same time.

• Journal of the Korean GEO-environmental Society
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• v.8 no.5
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• pp.5-14
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• 2007

The quantity of noxious wastes generated by the growth in industrialization and population in all over the world and its potential hazards in subsurface environments are becoming increasingly significant. The extraction of the contaminant from the soil and movement of the water are restricted due to the low permeability and adsorption characteristics of the reclaimed soils. Incorporated technique with PVDs have been used for dewatering from fine-grained soils for the purpose of ground improvement by means of soil flushing and soil vapor extraction systems. This paper is to evaluate several key parameters that affected to the performance of the PVDs specifically with regard to: well resistance of PVD, zone of influence, and smear effects. In the feasibility of contaminant remediation was evaluated in pilot-scale laboratory experiments. Well resistance is affected on the vertical discharge capacity of the PVDs under the various vacuum pressures. The discharge capacity increases consistently in areal extents with higher applied vacuum up to a limiting vacuum pressure. The head values for each piezometer at different vacuum pressures show that the largest head loss occurs within 14 cm of the PVD. Air flow rates and head losses were measured for the PVD placed in the model test box and the gas permeability of the silty soils was calculated. Increasing the equivalent diameter results in a decrease in the calculated gas permeability. It is concluded that the gas permeability determined over the 1,500 to 2,000 $cm^3/s$ flow rates are the most accurate values which yields gas permeability of about 3.152 Darcy.

• Journal of the Korean Institute of Gas
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• v.27 no.2
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• pp.39-48
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• 2023

This study presents the experimental results to measure the adsorption amount of methane gas by coal according to the conditions of a coalbed methane (CBM) reservoir. Adsorbed gas to coal seam particles was measured under reservoir conditions (normal pressure ~ 1,200 psi pressure range, temperature range15 ~ 45℃) using coal samples obtained from random mines in Kalimantan Island, North Indonesia. The obtained amount of absolute adsorbed gas was applied to triangular with linear interpolation to calculate the maximum amount of adsorbed gas according to temperature and pressure change, at which no experiment was performed. As a result, it was revealed that the amount of adsorbed gas to coal particles increased as the pressure increased and temperature decreased, but the increase of the amount of adsorbed gas decreased at more than an appropriate depth(1,000 ft). In the cleat permeability and cleat porosity for each depth of the coal bed considering the effective stress, the cleat permeability was 28.86 ~ 46.81 md, and the cleat porosity was 0.83 ~ 0.98%. This means that the gas productivity varies significantly with the depth because the reduction of the permeability according to the depth in the coal seam is significant. Therefore, a coalbed depth should be considered essential when designing the spacing of production wells in a coalbed methane reservoir in further study.

• Membrane Journal
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• v.23 no.6
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• pp.393-408
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• 2013

Gas separation processes using polymeric membranes have been greatly developed during the last few decades due to high energy efficiency and economic advantages. To achieve optimum economic performance, gas separation membranes required high permeability and selectivity. So, a number of reports examining the various polymeric materials for gas separation membranes have been published. Among the studied materials, polyimide (PI), which exhibit high permselectivity for various gas pairs, high chemical resistance, thermal stability, and mechanical strength, have attracted much attention. This paper focuses on the basic principle of gas separation, preparation procedure of membrane along with the recent developments and research trends of PI based materials for gas separation.

• Membrane Journal
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• v.27 no.2
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• pp.147-153
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• 2017

In this study, we investigated permeation properties of single gas ($N_2$, $O_2$, $CO_2$) through membranes composed of poly(ethylene oxide) (PEO) and poly(ethylene-co-vinyl acetate) (EVA) blend. The prepared membranes showed no new absorbance peaks, which indicate the physical blending of PEO and EVA by FT-IR analysis. SEM observation showed that the crystalline phase of PEO decreased with increasing EVA content in the PEO/EVA mixed matrix. DSC analysis showed that the crystallinity of the PEO/EVA blend membrane decreased with increasing EVA content. Gas permeation experiment was performed with various feed pressure (4~8 bar). The permeability increased in the following order: $N_2$ < $O_2$ < $CO_2$. The permeability of $CO_2$ in PEO/EVA blend membranes were increased with increasing feed pressure, However, the permeability of $N_2$ and $O_2$ were independent of feed pressure. On the other hand, the permeability of all the gases in PEO/EVA blend membranes increased with increasing amorphous EVA content in semi-crystalline PEO. In particular, the blend membrane with 40 wt% EVA showed $CO_2$ permeability of 64 Barrer and $CO_2/N_2$ ideal selectivity of 61.5. The high $CO_2$ permeability and $CO_2/N_2$ ideal selectivity are attributed to strong affinity between the polar ether groups of PEO or the polar ester groups of EVA and polar $CO_2$.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.2
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• pp.72-75
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• 2005

In oil-filled equipment such as transformers, partial discharge or local overheating will precede a final shutdown. Accompanied with such problems is a decomposition of insulating material into gases, which are dissolved into the transformer oil. The gases dissolved in oil can be separated with some membranes based on the differences in permeability of membranes to different gases. This paper discuss the permeability characteristics of several membranes for separation hydrogen gas in oil. With result of this paper, it may become possible to detect fault-related gases from transformer oil and predict incipient failures in the

• Journal of Korean Society of Environmental Engineers
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• v.22 no.7
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• pp.1233-1241
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• 2000

The purpose of this study is to see the remediability and pilot system operating condition on diesel contaminated areas. Air permeability(k) and trend of gas phase ($O_2/CO_2/VOCs$) concentration to determine the remediation rate of the contaminated sites are very important. So we tested air permeability and trend of gas phase concentration. Throughout soil vapor extraction(SVE) and bioventing hybrid pilot test on different conditions, the range of air permeability(k) was 1985~1194 darcy. The tests result in soil vapor extraction and bioventing hybrid system was appropriate on this test sites, and the suitable injection air flow rate was $3.5m^3/hr$.