• 한국가스학회지
• /
• 제21권2호
• /
• pp.50-57
• /
• 2017

셰일 저류층은 매우 미세한 입자로 구성되어 있으며, 공극의 크기가 나노미터에 불과하다. 본 연구에서는 셰일 암체에서의 크누센 확산영향, 균열대 및 암체에서 상대투과도, 셰일가스 생산에 따른 균열투과도 변화를 적용하여 그 영향을 분석하였다. 이를 위해 캐나다 혼리버 셰일 저류층 모델을 구축하였으며, 장기간 생산을 하는 셰일 저류층에서의 확산 및 선행연구에서 제안된 균열대 상대투과도를 적용하여 생산성에 미치는 영향을 분석하였다. 그리고 암체와 균열대에서 동생수가 생산성에 미치는 영향과 저류층 생산에 따른 균열투과도 변화를 적용하여 생산성을 평가하였다.

• 한국세라믹학회지
• /
• 제32권3호
• /
• pp.349-358
• /
• 1995

The ceramic composite membrane was synthesized by thermal oxidation after evaporation of Al on the support prepared by slip casting process. Oxidation was performed at $700^{\circ}C$ and 80$0^{\circ}C$ under dry oxygen atmosphere. It was considered as optimum oxidation condition that the membrane showed a knudsen behaviro. A further oxidation resulted in an increase of gas permeability because top layer became densified. Then, a multi-layered composite membrane was synthesized through a sol-gel method, evaporation and thermal oxidation of Al coating processes. While the membrane was thermally stable up to 80$0^{\circ}C$, gas permeability was rapidly decreased even at a slight amount of deposition of Al.

• 한국세라믹학회지
• /
• 제33권1호
• /
• pp.110-118
• /
• 1996

• 공업화학
• /
• 제10권4호
• /
• pp.502-508
• /
• 1999

서로 다른 기공크기를 가진 $Al_2O_3$막을 기질로 사용하여 단량체인 $CHF_3$로 플라즈마 중합시키고, 플라즈마 중합된 막을 Ar 플라즈마로 처리하여 표면을 개질시켜 $O_2/N_2$에 대한 투과도와 선택도를 비교하여 그 특성을 검토하고 기질의 기공크기가 투과메카니즘에 미치는 영향을 살펴보았다. 중합된 고분자 막을 cathode에 근접한 위치에서 Ar 플라즈마의 처리 시간과 rf-power 출력에 따라 표면 처리하였을 때 질소에 대한 산소의 선택도는 크게 향상된, 반면 투과도는 저하됨을 확인하였다. 또한 동일한 증착조건에서 서로 다른 기공크기를 갖는 기질에 플라즈마 중합시켰을 때, 증착된 비 다공성막인 고분자막에서는 동일하게 용해-확산 모델이 적용되나, 비 다공성층을 통과한 분자들은 Knudsen 확산모델에 의해 기질의 크기와 투과도와의 상관관계를 나타냈으며, 이로부터 투과메카니즘은 중합된 고분자막의 기능기와 기질의 기공크기에 지배적인 영향을 받음을 알 수 있었다.

• 한국막학회:학술대회논문집
• /
• 한국막학회 1996년도 춘계 총회 및 학술발표회
• /
• pp.16-19
• /
• 1996

Separation with synthetic membrane have become increasingly important processes in many fields. In the most application of membrane process, polymer membrane is used. the main advantage of polymers as a material for membrane preparation is the relative simplicity of this film formation which enables one to obtain rather high permeability rates. However, polymeric membranes have several limitations, such as high temperature instability, swelling and decomposition in organic solvent, et. al.. These limitations can be overcome by inorganic membrane. At the present time, commercially available inorganic membranes have pore diameters ranging 5nm to 50mm, and the predominant flow regime in such membrane is Knudsen diffusion. Since the Knudsen permeability is directly proportional to the molecular velocity, gases can be separated due to their molecular masses. However, this separation mechanism is only of important for light gases such as H2 and He. Other separation mechanisms like surface diffusion, active diffusion can play an important role only with very small pore diameters(2nm) and give rise to large permselectivities. Therefore, preparation of inorganic membrane with nano-sized pore have been attracting more and more attention.

• 한국세라믹학회지
• /
• 제52권4호
• /
• pp.269-272
• /
• 2015

$La_2Ce_2O_7$ and $CeO_2$ membranes were fabricated from the corresponding powders derived from sol-gel process with polyvinyl alcohol binder. These powders and membranes were characterized by XRD, BET, and FE-SEM analysis. Hydrogen and CO gas permeation experiments were performed using Sievert's type equipment. Both fluxes on these membranes were found to decrease with increase of the temperature. This phenomenon was followed by the surface and Knudsen diffusion mechanism. The hydrogen permeability of the $La_2Ce_2O_7$ membrane was found to be $7.27{\times}10^{-5}mol/m^2sPa$, with perm-selectivity of 7.24 at 303 K.

• 멤브레인
• /
• 제24권6호
• /
• pp.438-447
• /
• 2014

무정형의 괴상의 다공성 borosilicate는 trimethylborate (TMB)/ tetraethylorthosilicate (TEOS) 몰비 0.01~0.10 겔체를 $700{\sim}800^{\circ}C$ 온도범위에서 열처리 하였을 때 얻어졌다. BET와 SEM 관찰에 의하면 $700{\sim}800^{\circ}C$에서 얻어진 borosilicate의 표면적은 $251.12{\sim}355.62m^2/g$이고, 기공직경은 3.5~4.9 nm이며, 입자크기는 30~60 nm이었다. TGA측정에 의하면 borosilicate가 poly[1-(trimethylsilyl)propyne](PTMSP)에 첨가되었을 때 PTMSP-borosilicate 복합막의 열적 안정성은 향상 되었다. SEM관찰에 의하면 borosilicate는 $1{\mu}m$ 크기로 복합막 내에 분산되어 있었다. 기체투과실험에 의하면 PTMSP에 borosilicate 함량이 증가하면 자유부피, 공동, 기공률이 증가하여 기체투과가 용해확산에 의한 것보다 분자체거름, 표면확산, Knudsen 확산에 의해 일어나는 경우가 점차 증가함으로 해서 $H_2$와 $N_2$의 투과도는 증가하고 선택도($H_2/N_2$)는 감소하였다.

• 한국세라믹학회지
• /
• 제32권3호
• /
• pp.385-393
• /
• 1995

Akali-resistant porous glass was prepared by phase separation in Na2O-B2O3-SiO2 system containing ZrO2 and MgO. ZrO2 was added for alkali-resistance and MgO for anti-cracking during leaching. Optimal content of ZrO2 for alkali-resistance was 7wt% and devitrification by heat treatment resulted from further addition. Pore size and pore volume were decreased and specific surface area was increased with ZrO2 addition due to depression in phase separation. Addition of 3mol% MgO to mother glass containing 7wt% ZrO2 was effective for anti-crack during leaching. In this case, with phase separation at 55$0^{\circ}C$ and 5$25^{\circ}C$ for 20 hrs. crack-free porous glasses could be prepared. The relation between pore size r and heat treatment time t at 55$0^{\circ}C$ was D=25.58＋18.16t. According to measurement of gas permeability, the mechanism of gas permeation was Knudsen flow. N2 and He permeability of porous glass which was prepared by heat treatment at 55$0^{\circ}C$ for 20 hrs. were 0.843$\times$10-7mol/$m^2$.s.Pa and 2.161$\times$10-7mol/$m^2$.s.Pa respectively.

• 한국수소및신에너지학회논문집
• /
• 제24권3호
• /
• pp.200-205
• /
• 2013

The separation of hydrogen depends on porosity, diffusivity and solubility in permeation membrane. Dense membrane is always showing a solution diffusion mechanism but porous membrane is not showing. Therefore, porous membrane has a good hydrogen flux due to pore is carried out transferred media. This mechanism is named as the Knudsen diffusion. Hydrogen molecules or hydrogen atoms are diffused along pore that is a mean free path. In this study, complex layer hydrogen permeation membrane was fabricated by hot press process. And then, it was evaluated and calculated to relationship between hydrogen permeability and membrane porosity.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• 제24권1호
• /
• pp.103-119
• /
• 2020

In this work, the hydromagnetic and thermal characteristics of natural convection flow in a vertical parallel plate micro-porous-channel with suction/injection is analytically studied in the presence of Hall current by taking the temperature jump and the velocity slip at the wall into account. The governing equations, exhibiting the physics of the flow formation are displayed and the exact analytical solutions have been obtained for momentum and energy equations under relevant boundary conditions. The impact of distinct admissible parameters such as Hartmann number, Hall current parameter, permeability parameter, suction/injection parameter, fluid wall interaction parameter, Knudsen number and wall-ambient temperature ratio on the flow formation is discussed with the aid of line graphs. In particular, as rarefaction parameter on the micro-porous-channel surfaces increases, the fluid velocity increases and the volume flow rate decreases for injection/suction.