CHARACTERISTICS OF EXHAUST EMISSIONS CONVERSION OF COMMERCIAL CU- AND FE-SCR CATALYTS |
Choong-kil Seo1, Kyung seok Lee2 |
1Howon University 2Chonnam National University |
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ABSTRACT |
The purpose of this study is to identify the performance of the SCR catalyst according to the thermal aging, coking and space velocity subjected for commercial catalysts (Cu- and Fe-SCR). The Cu-SCR (Fresh) catalyst showed 83 % of high NOx reduction rate in the low temperature of 200 oC, and the performance window of NOx reduction rate was established widely in all temperature ranges. Fe-SCR (800 oC 22hr) catalyst was slightly improved with the NOx reduction rate compared to the Fe-SCR (Fresh) catalyst, and this was due to the increase in the intensity of acid site due to the dealuminization. Cu-SCR (0.1 g coking) catalyst reduced NOx reduction rate by about 20 ~ 40 % compared to the Fresh catalyst due to the clogging of the catalyst active site by the carbon. When carbon of 0.1 g was deposited on the Cu- and Fe-SCR catalysts, it was reduced to NOx conversion rate because metal was deposited on active site of the SCR catalyst. In the effect of the space velocity of Cu-SCR (Fresh) catalysts, SV 44,000 h-1 and 56,000 h-1 reduced NOx conversion rate by about 15 ~ 40 % at the overall temperature compared to 28,000 h-1. The larger the SV, the time for the exhaust gas to react with the catalysts is shortened. For SV 40,000 h-1 and 56,000 h-1, NOx conversion rate was equivalent. |
Key Words:
Diesel Engine, NOx, Lean NOx Trap, SCR, Coking, Space Velocity |
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