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유기금속화학증착법(MOCVD)에 의해 제조된 기체분리용 SiO_(2)/Al_(2)O_(3) 복합막의 특성 연구

(A) Study on the properties of gas permselective SiO_(2)/Al_(2)O_(3) composite membranes formed by sol-gel and Metal-organic chemical vapor deposition

초록/요약

Hydrogen-permselective membranes were synthesized by sol-gel method and metal organic chemical vapor deposition of SiO_(2)/Al_(2)O_(3) layers on the inner walls α-alumina tubes at 400-600℃ and latm, using the precursors such as tetraethyl orthosilicate(TEOS) and aluminum tri-sec butoxide(ATSB). The thin films of each oxide produced were characterized for their gas permeabilities and microstructures. An avaerage pore size of porous alumina(YCF-0.1) used for support is 0.13㎛, and permeance through pore is controlled by Knudsen diffusion. Although average pore size is 25 times as that of Vycor glass, pore of α-alumina is easily plugged by TEOS and ATSB. In case of deposition directly on porous alumina, permeance of nitrogen as well as that of hydrogen is decresed, therefore film had no hydrogen-selectivity. Controlling sweeping gas made no effect on thickness of thin films. As a result of slurry conting on inner wall porous alumina, surface roughness was decreased and pore size distribution was narrowered. Deposition SiO_(2)/Al_(2)O_(3) thin film on it relieve roughness of film surface. But hydrogen-selectivity was not improved. γ-alumina layer made formed on slurry coating layer by sol-gel method. Gas permeation of this thin film was in Knudsen diffudion region Hydrogen permeance was 1.26×10^(-7) mol/m^(2).s.Pa and a selectivity for hydrogen over nitrogen was 17 at 600℃. As deposition temperature was increased(400-600℃), deposition rate and selectivity was increased. Composite membrane indicates that permeation of hydrogen occurs through a temperature-ativated diffusion, but nitrogen Knudsen diffusion.

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목차

목차 = ⅰ
List of figures = ⅳ
List of Tables = ⅶ
Abstract = ⅷ
Ⅰ. 서론 = 1
Ⅱ. 이론적 배경. = 5
1. 기체투과/분리 메카니즘. = 5
1.1 비다공성(non-porous) 무기막의 투과 메카니즘. = 5
1.1.1. 이온 확산 (Ion Diffusion) = 7
1.1.2. 고체 확산(Solid Diffusion) = 8
1.2. 다공성 무기막의 투과 메카니즘. = 8
1.2.1. 점성유동(Viscous Flow) = 10
1.2.2. Knudsen 유동 (Knudsen Flow). = 11
1.2.3. 표면확산(Surface Diffusion) = 12
1.2.4. 모세관 응축(Capillary Condensation) = 14
1.2.5. 활성확산(Activated Diffusion) = 15
1.2.6 분자체분리(Molecular Sieving) = 16
2. 무기막의 응용분야. = 16
2.1. 기체분리(Gas Separation) = 17
2.2. 촉매 막 반응기(Catalytic Membrane Reactor) = 18
2.2.1. 비다공성 무기막 반응기. = 18
2.2.2. 다공성 무기막 반응기. = 19
3. 박막 제조 방법. = 20
3.1. 화학증착법(Chemical Vapor Deposition; CVD) = 20
3.2. Sol-Gel 법 = 23
Ⅲ. 실험. = 25
1. 실험재료. = 25
2. 실험 장치. = 25
3. 박막제조. = 27
3.1. 슬러리 코팅(slurry coating) = 27
3.2. Sol의 제조 및 코팅. = 28
3.2.1. Boehmite sol = 28
3.2.2. Sol-gel coating. = 30
3.3. 화학증착법에 의한 박막제조. = 30
4. 기체투과도 측정. = 32
5. 박막의 특성분석. = 34
Ⅳ. 결과 및 고찰. = 35
1. 다공성 알루미나 지지체 사용 = 35
1.1. 다공성 지지체(YCF-0.1)의 기체투과 및 구조적 특성. = 35
1.2. 다공성 지지체 + CVD에 의한 SiO_(2)/Al_(2)O_(3) 복합 박막 제조. = 39
1.2.1. 지지체로서 Vycor glass와 YCF-0.1 비교 = 39
1.2.2. Sweeping gas의 영향. = 43
2. 다공성 알루미나 + 슬러리 코팅 지지체 사용 = 50
2.1. 슬러리 코팅층의 특성. = 50
2.2. 다공성 알루미나 + 슬러리 코팅 + CVD에 의한 SiO_(2)/Al_(2)O_(3) 복합 박막 제조. = 53
3. 다공성 알루미나 + 슬러리 코팅 + Sol-gel 코팅 지지체 사용 = 56
3.1. Sol-gel 코팅층의 기체투과 및 구조적 특성 = 56
3.2. 다공성 알루미나 + 슬러리 코팅 + Sol-gel 코팅 + CVD에 의한 SiO_(2)/Al_(2)O_(3) 복합 박막 제조. = 59
3.2.1. 제조 변수로서 온도의 영향. = 59
3.2.2. 제조 변수로서 TEOS/ATSB 농도비의 영향 = 63
4. 박막 담지 무기막의 기체 투과 특성 = 66
Ⅴ. 결론 = 69
참고문헌 = 71
부록 = 77

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