• Proceedings of the Membrane Society of Korea Conference
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• 1998.10a
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• pp.50-52
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• 1998

1. 서론 : 오래전부터 기체를 액상에 분산시킴으로써 물질 전달 속도를 증가시킴과 동시에 기-액간의 접촉면적을 넓히려는 연구 즉, 기-액간의 접촉 경계면을 통하여 이루어지는 기체흡수에 관한 연구가 다각적으로 이루어져 왔다. 그러나, 기존의 흡수장치에서는 기-액간의 접촉면적을 정확히 계산할 수 없고, 기체에 의한 액체의 범람이나 편류현상등이 발생하여 액체나 기체의 유속에 제한을 주는 등 기술적인 문제점을 가지고 있다. 따라서 이러한 기존 흡수공정들의 문제점을 극복하기 위하여 최근에 제안된 것이 막을 이용하여 기체와 흡수제인 액체의 접촉을 인위적으로 제어할 수 있는 중공사막 접촉기이다. 본 연구에서는 수용성 흡수제가 흡수모듈과 탈착모듈을 순환하는 순환식 중공사막 접촉기를 이용하여 혼합기체(N$_2$/CO$_2$ = 80/20)로부터 이산화탄소를 선택적으로 분리.회수하고자 하였으며, 또한 흡수제의 농도, 유속변화, 그리고 진공식 탈착모듈에서 압력변화에 따른 기체투과 특성을 고찰함으로써 운전조건의 최적화와 그 응용 가능성을 제시하고자 하였다.

• Korean Chemical Engineering Research
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• v.45 no.1
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• pp.81-86
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• 2007

Hollow fiber membrane G-L contactors are widely used to remove $SO_2$ emitted from industrial facilities. In this work, the mathematical modeling and computer simulation for hollow membrane G-L contactors is carried out to analyze $SO_2$ absorption behavior in hollow fiber membranes. The model is solved with the finite element method using a commercial software. Investigated is the dependency of $SO_2$ removal efficiency and mass transfer characteristics on gas velocities, membrane mass transfer coefficients and physical properties of contactors. The membrane mass transfer coefficients are estimated by fitting the experimental data with the simulated $SO_2$ removal efficiencies. In addition, a design methodology of membrane contactors is suggested.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.10a
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• pp.61-64
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• 1997

1. 서론 : 적절한 이산화탄소의 분리는 지구온난화의 가속현상을 늦출 수 있을 뿐만 아니라 각종 탄화수소가스의 원료로 분리 정제된 이산화탄소를 재이용할 수 있으므로 경제적으로 매우 중요하다. 이산화탄소 분리에 사용되던 기존 공정들의 단점을 보완할 수 있는 대체방안으로 최근에 개발되기 시작한 것이 소수성의 다공성 고분자 분리막(hydrophobic porous ploymeric membrane) 방법인데, 이는 모듈의 유효 막 표면적이 상대적으로 크고 기체와 액체의 흐름을 독립적으로 제어할 수 있으므로 범람 등의 현상이 없으나 막 자체의 저항이 비교적 큰 단점을 가지고 있다. Qi와 Cussler는 이러한 특성을 가지는 중공사막 모듈에서의 기-액 흐름에 대한 물질전달 상관관계식을 얻었으며[1], Karoor 등은 여러 가지 중공사막 모듈을 사용하여 순수물과 diethanolamine(DEA) 등의 흡수제에 대한 이산화탄소의 물질전달 거동을 수치모델과 실험을 통하여 고찰하였다[3]. 또한 중공사막 접촉기의 실제적 응용에 대하여 Matsumoto 등은 화력발전소에서 발생하는 연소가스 내의 이산화탄소 흠수에 대한 연구를 수행하였다[4]. 본 연구에서는 중공사막 접촉장치를 사용하여 흡수제를 순수물과 탄산칼륨($K_2CO_3$)을 사용했을 경우의 이산화탄소의 분리 거동을 수치모델과 실험을 통하여 고찰하였다. 수치모델의 경우 이전까지의 연구가 반응이 없는 경우나 반응식을 간략화시킨 경우에 한정되었는데 비하여, 반으이 있는 경우 각각의 반응물질들의 거동을 고려한 반응식을 유도하여 해를 구하고자 하녔다.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.521-528
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• 2008

The micro-porous asymmetric PVDF hollow fiber membranes for gas-liquid contactor were prepared by the dry-jet wet phase inversion process and the characteristics of hollow fiber membranes were evaluated by the gas permeation method and scanning electron microscope. The chemical absorbent for removal of $SO_2$ gas was sodium hydroxide at bench scale hollow fiber membrane contactor. The experiments were performed in a counter-current mode of operation with gas in the shell side and liquid in the fiber lumen of the module to examine the effect of various operating variables such as concentration of absorbent, gas flow rate, L/G ratio and concentration of inlet $SO_2$ gas on the $SO_2$ removal efficiency using PVDF hollow fiber membrane contactor. Membrane mass transfer coefficient($k_m$) was calculated by mathematical modeling. The volumetric overall mass transfer coefficient increased with increasing the concentration of absorbent and L/G ratio. The increase of the absorbent concentration and L/G ratio not only provides more sufficient alkalinity but also decreases liquid phase resistance. The volumetric overall mass transfer coefficient increased with increasing gas flow rate due to decreasing the gas phase resistance.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.4
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• pp.503-510
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• 2011

Ammonia in water which is toxic to human, its concentration is regulated below 0.5 mg/L in drinking water. Current study aimed to develop appropriate models for ammonia stripping using hollow fiber membrane contactor. Two different models were developed during the study. Model 1 was assumed only free ammonia ($NH_3$) transfer in stripping process, whereas the Model 2 was assumed with total ammonia ($NH_3+{NH_4}^+$) transfer. Ammonium chloride ($NH_4CI$), sodium hydroxide(NaOH) were used to make ammonia solution, which was concentration of 25 mg as N/L at a pH of 10.5. The experimental conditions were such that, the liquid flow was in tube-side in upward direction and t he gas flow was on shell-side in downward direction a t room temperature. The experimental and modeling results showed that marginal difference were observed at low gas flux. However the difference between the both models and experimental value were increased when the gas flux was increased. The study concludes that the Model 1 with free ammonia is more appropriate when both models were compared and useful in ammonia stripping process at low gas flux.

• Proceedings of the Membrane Society of Korea Conference
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• 2008.05a
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• pp.245-248
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• 2008

• Proceedings of the Membrane Society of Korea Conference
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• 2008.05a
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• pp.249-252
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• 2008

• Proceedings of the Membrane Society of Korea Conference
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• 2008.05a
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• pp.114-117
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• 2008

• Korean Chemical Engineering Research
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• v.43 no.1
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• pp.161-169
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• 2005

Numerical simulation and experiments were carried out on the absorption of carbon dioxide using PVDF hollow-fiber membrane contactor. Water or monoethanolamine (MEA) aqueous soluton was used as absorbents. Simulation results showed that the concentration profile of carbon dioxide was less affected by the flow rate of MEA than that of water absorbent. The absorption rate and mass transfer coefficient of carbon dioxide increased as the concentration of MEA increased. The mass transfer coefficients obtained by experiments coincided with those obtained by numerical simulation and theoretical results for $CO_2-water$ system. However, for $CO_2-MEA$ system, the mass transfer coefficients obtained by experiments were lower than those obtained by simulation, while the simulation results agreed well with theoretical results. The durability of plasma-treated hollow fiber membranes was better than that of no plasma-treated ones.

• Membrane Journal
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• v.26 no.2
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• pp.126-134
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• 2016

To produce renewable biomethane from biogas, the properties of physical absorbents such as water, methanol, 1-methyl-2-pyrrolidone (NMP), poly(ethylene glycol) dimethylether (PEGDME), and propylene carbonate (PC) were studied, and PC was applied to membrane contactor systems. Among physical absorbents, PC exhibited a high contact angle of $58.3^{\circ}$ on polypropylene surface, and a PC/water mixture (5 wt%) increased the contact angle to $90^{\circ}$. Furthermore, the PC/water mixture presented higher $CO_2$ absorption capacities (0.148-0.157 mmol/g) than that of water (0.121 mmol/g), demonstrating a good property as an absorbent for membrane contactors. Actual operations in membrane contactors using the PC/water mixture resulted in $CO_2$ removal of 98.0-97.8% with biomethane purities of 98.5-98.3%, presenting a strong potential for biogas treatment. However, the PC/water mixture yielded moderate improved in $CO_2$ removal and methane recovery, as compared with water in the membrane contactor operation. This is originated from insufficient desorption processes to reuse absorbent and low $CO_2$ flux of the PC/water absorbent. Thus, it is requiring optimizations of membrane contactor technology including development of absorbent and improvement of operation process.