| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent SOx intoxication in a NOx catalyst. SOLUTION: A NOx catalyst 20 and a bypass pipe 26 bypassing the NOx catalyst 20 are provided downstream from an SOx absorbent 17, and an exhaust gas selector valve 28 switching the flow of exhaust gas at a leading end of the bypass pipe 26. Recovery process is applied to the SOx absorbent 17 before SOx releasing process is applied to the NOx catalyst 20. The exhaust gas selector valve 28 is controlled, such that the exhaust gas is prevented from flowing through the NOx catalyst 20 by conducting the exhaust gas through the bypass pipe 26 during the recovery process of the SOx absorbent 17, and the exhaust gas is prevented from flowing through the bypass pipe 26, by conducting the exhaust gas through the NOx catalyst 20 during the SOx releasing process of the NOx catalyst 20.</p> |
