| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce device cost when installing a plurality of NOx removal devices. <P>SOLUTION: The NOx removal devices 10a, 10b are installed in a plurality of systems of exhaust gas flow passages, sample pipes 8a, 8b are connected to the portions of the exhaust gas passages 2a, 2b downstream of the NOx removal devices, and other ends of the sample pipes are connected to a common NOx value measurement device 6 so that an outlet NOx value in each of the exhaust gas passages is detected. In the NOx removal devices 10, 10b provided in the exhaust gas passages, the amount of the reducing agent supplied is regulated based on the measured outlet NOx value at a side where the NOx value measurement device 6 measures the outlet NOx value, and the amount of the reducing agent supplied is regulated based on a previous final value reserved during the previous measurement on a side where the NOx value measurement device 6 does not measure the outlet NOx value in each of the exhaust gas passages. The outlet NOx value measurement is switched when such a condition is satisfied that a switching condition time or longer elapses from the previous switching, and the outlet NOx value is stabilized. <P>COPYRIGHT: (C)2010,JPO&INPIT |
