Modification of catalysts for simultaneous control of NO and fly ash in a fluidized-bed catalyst reactor
| Autor: | Shih-Teng Huang, 黃世騰 |
|---|---|
| Rok vydání: | 2010 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 98 This study investigated the simultaneous removal of nitric oxide (NO) and fly ash by a fluidized-bed catalyst reactor from simulated flue gas. The activated carbon (AC) supports were pretreated by the wet chemical treatment method. After that, the copper catalysts were prepared by wet impregnation method using the modified supports to evaluate the NO reduction efficiency. The effects of different concentrations of fly ash and operation time on the simultaneous removal of NO and fly ash were also considered. Besides, the catalysts were characterized by the field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and Brunauer Emmett Teller (BET). The results of activity test showed that the activities of CuO/AC catalysts with different pretreated AC supports were followed the sequence as CuO/AC-N > CuO/AC-S > CuO/AC-H > CuO/AC-Na at temperature was 250 oC. Accordingly, the CuO/AC-N was employed in the experiment of simultaneous removal of NO and fly ash in flue gas. The results of different concentrations of fly ash showed that the removal efficiency of fly ash was stable in the range of fly ash concentration between 1406 to 49108 mg/m3 within 30 min. High tolerance ability for fly ash was found by using fluidized bed catalyst reactor. On the other hand, the NO conversion presented a slight change when the concentrations of fly ash lower than 10173 mg/m3 within 30 min. But the NO conversion was decreased when the concentration of fly ash was 49108 mg/m3. The results can be explained that decreasing of the catalyst activity was owing to the active sites of the catalysts blocked or occupied by fly ash in high concentration of fly ash environment. In the experiment of different operating time, the results indicated that removal efficiency of fly ash decreased with increasing of the operating time when the fly ash concentration was 10173 mg/m3. In addition, the NO conversion was maintained about 65 % in the operation time within 90 min, but it significantly decreased after 90 min. It can be considered that the presence of fly ash influenced the activity of CuO/AC-N catalysts. This accumulation behavior of fly ash on the catalyst surfaces reduced the performance of NO conversion when operating time increased. Moreover, the BET results also showed that the decreasing of the volumes of meso- and macro-pore with operating time increased because of fly ash blocked the catalyst surface. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|