Hashim, Siti Salwa Hashim (2015) Development of CuO-TiO₂-La0.6Sr0.4Co0.2Fe0.8O3-δ Mixed Ionicelectronic Conducting Ceramic Membrane for Oxygen Separation. PhD thesis, Universiti Sains Malaysia.
![[img]](http://eprints.usm.my/style/images/fileicons/application_pdf.png)
|
PDF
- Submitted Version
Download (695kB) | Preview |
Abstract
Kajian ini memfokuskan kepada penyediaan membran La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) untuk pemisahan oksigen pada suhu persinteran yang lebih rendah menggunakan campuran 83.3 mol% CuO-16.7 mol% TiO₂ (0-3% berat) sebagai aditif. Kesan penambahan aditif terhadap sifat persinteran, struktur kristal, mikrostruktur, modulus Young, kekuatan lenturan dan kadar penelapan oksigen bagi membran LSCF telah dikaji. Penambahan campuran CuO-TiO₂ tidak menganggu struktur kristal membran LSCF. Penambahan 1% berat campuran CuO-TiO₂ telah menurunkan suhu persinteran membran LSCF sebanyak 200°C. Membran LSCF dengan 1% berat campuran CuO-TiO₂ yang disinter pada suhu serendah 1100°C menghasilkan kemampatan relatif melebihi 94% serta mempunyai kekuatan lenturan dan modulus Young yang tinggi. Kadar penelapan oksigen pada suhu 600°C bagi membran tersebut adalah yang tertinggi (0.079 ± 0.001 ml/cm².min); iaitu 1.8 kali ganda lebih tinggi berbanding membran LSCF tanpa campuran CuO-TiO₂ yang disinter pada 1300°C (0.04 ± 0.003 ml/cm².min). Justeru, membran LSCF dengan 1% berat campuran CuO-TiO₂ yang disinter pada 1100°C telah dipilih untuk mengkaji kadar penelapan oksigen pada kondisi yang berbeza. Data eksperimen menunjukkan bahawa kadar penelapan oksigen meningkat dengan peningkatan suhu, tekanan separa oksigen dalam komposisi suapan dan kelajuan gas penyapuan; dan menurun dengan peningkatan ketebalan membran. Untuk membran dengan ketebalan 1.10 mm, kondisi eksperimen optimum bagi kadar penelapan oksigen ialah pada suhu 600°C, tekanan separa oksigen dalam komposisi suapan 1 atm dan kelajuan gas penyapuan 100 ml/min. Kadar penelapan oksigen sebanyak 0.180 ± 0.02 ml/cm².min telah diperoleh dengan gabungan kondisi eksperimen tersebut. Model matematik yang bersesuaian telah diusulkan untuk menentukan parameter penelapan oksigen berdasarkan data eksperimen. Data prediksi telah dibandingkan dengan data eksperimen untuk pengesahan model matematik yang diusulkan. Perbandingan antara data eksperimen dengan data prediksi menunjukkan keselarasan yang baik. Model matematik yang diusulkan juga menunjukkan bahawa kadar penelapan oksigen bagi ketebalan membran dalam julat 1.10-2.70 mm yang digunakan dalam kajian ini dipengaruhi oleh mekanisma difusi ruah. ________________________________________________________________________________________________________________________ This study focuses on the preparation of La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) membrane for oxygen separation at low sintering temperature by using 83.3 mol% CuO-16.7 mol% TiO₂ mixture (0-3 wt.%) as additives. The effect of the additives on the sintering behavior, crystal structure, microstructure, Young’s modulus, flexural strength and oxygen permeation flux of the LSCF membrane have been investigated. The crystal structure of the LSCF membrane has not been affected by the CuO-TiO2 mixture addition. The addition of 1 wt.% CuO-TiO2 mixture has reduced the sintering temperature of the LSCF membrane by 200°C. The LSCF membrane with 1 wt.% CuO-TiO2 mixture sintered at 1100°C has obtained a relative density of over 94% with high flexural strength and Young’s modulus. Its oxygen permeation flux at 600°C is also the highest (0.079 ± 0.001 ml/cm².min); which is about 1.8 times higher than the pure LSCF membrane sintered at 1300°C (0.044 ± 0.003 ml/cm².min). The LSCF membrane with 1 wt.% CuO-TiO2 mixture sintered at 1100°C has been chosen for further oxygen permeation performance studies at different conditions. The experimental results show that the oxygen permeation flux increases with the increase of temperature, oxygen partial pressure in the feed side and sweep gas flow rate; and decreases with the increase of membrane thickness. For the 1.10 mm thick membrane, the optimum experimental conditions for oxygen permeation flux have been found to be 600°C temperature, 1 atm oxygen partial pressure in the feed side and 100 ml/min sweep gas flow rate. The oxygen permeation flux of 0.180 ± 0.02 ml/cm².min has been obtained using these co-optimized experimental conditions. The oxygen permeation parameters have been determined from the experimental data by proposing a suitable mathematical model. The predicted data have been compared with the experimental data in order to validate the proposed model. Good agreement has been achieved between predictions and experimental data. The proposed model also indicates that in the 1.10-2.70 mm thickness range used in the present study, the oxygen flux is predominatly controlled by bulk diffusion mechanism across the membrane.
| Item Type: | Thesis (PhD) |
|---|---|
| Additional Information: | Full text is available at http://irplus.eng.usm.my:8080/ir_plus/institutionalPublicationPublicView.action?institutionalItemId=2121 |
| Subjects: | T Technology T Technology > TP Chemical Technology > TP155-156 Chemical engineering |
| Divisions: | Kampus Kejuruteraan (Engineering Campus) > Pusat Pengajian Kejuruteraan Kimia (School of Chemical Engineering) > Thesis |
| Depositing User: | Mr Mohd Jasnizam Mohd Salleh |
| Date Deposited: | 13 Jun 2018 04:04 |
| Last Modified: | 13 Jun 2018 04:04 |
| URI: | http://eprints.usm.my/id/eprint/40783 |
Actions (login required)
 |
View Item |
