This study utilized Cu-catalysts to catalyze a NO reduction reaction using CH4 as a reductant. Due to CH4 being a weak reductant and is easily affected by O2 concentration, we undertook a series experiments with O2 concentration and promoters, so that we could better understand their influence. The experiment conditions were as follows : reaction temperature between 150¢J- 800¢J¡Fa catalysts weight of 0.5 g¡F total gas flow rate of 1000 ml/min¡Frelative humidity at 0.9 %¡Fan O2 concentration between 0 - 6%¡Fand CH4 concentration between 1000 - 10000 ppm.
First, we sorted out the best metal carriers and calcining temperature, from this we decide to use £^-Al2O3 as a carrier with a calcining temperature under 500¢Jto produce our catalysts. During the O2 concentration experiment, when the inflow O2 concentration was below 1% (including 0% O2), Cu-catalysts reduce NO above 550¢J.The conversion reached a rate of 95 % at a temperature of 750¢J¡Fwhen the oxygen concentration was between 3% and 6% O2, catalysts reacted within 300 - 500¢J with NO converting to NO2¡Fat a concentration between 1.5% and 2% O2, NOx underwent reduction at 750¢J,and NOx conversion raised from 0 % to above 90%. Therefore in analyzing the experiment results, it shows that NOx will reduce violently when the O2 concentration is below 0.7% and while using CH4 as a reductant. This result was also apparent in O2 concentrations between 1.5 % and 2%. In the experiments of M/O ratio (the ratio of CH4 and O2 inflow), we found M/O ratio was not a deciding factor within the reaction mechanics, furthermore the limiting factor of O2 concentration decreases under 0.7%¡Fin addition it was also found that adding large amounts of CH4 could quicken the reduction process. Lastly, a mass balance was performed, which had a result over 70 %.
In the experiments where Y¡BLa¡BSr¡BCo were added as promoters to the Cu-catalysts, we found that Cu-La/£^-Al2O3¡BCu-Sr/£^-Al2O3 and Cu-Co/£^-Al2O3 can accelerate O2 depletion. Henceforth, it is possible to deduce promoters will be a useful method in solving O2 limiting. In the comparison of metals loading methods, we found no difference in activity using separate-impregnation and co-impregnation methods, whereas in the BET and SEM co-impregnation experiments, there was a larger surface-area and dispersion.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0914101-142042 |
| Date | 14 September 2001 |
| Creators | Liu, Kai-Chung |
| Contributors | Hsi-Sheng Teng, Jie-Chung Lou, Chung-Shin Yuan, James Lee |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0914101-142042 |
| Rights | unrestricted, Copyright information available at source archive |
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