| 摘要 |
PROBLEM TO BE SOLVED: To denitrify exhaust gas by making a denitrification rate accurately constant, if there is a sharp load variation. SOLUTION: An addition molar ratio m2 is sought by adding a molar ratio correction value mc which corrects a rate of denitrification so that the rate is constant, if there is a load variation, to a molar ratio ml complying with a fuel demand 2. Further, an ammonia flow rate is controlled so that a calculated quantity of ammonia 6 obtained by multiplying the addition molar ratio m2 by a total quantity of NOX 5 and an actual quantity of ammonia 8 show a deviation of O. On the other hand, a residual quantity of ammonia 27 obtained by subtracting the rate of denitrification 23 obtained based on the actual quantity of ammonia 8 from a value 1 is multiplied by a differential rate of variation 29 in NOX at the entrance which is obtained by differentiating a rate of variation 11 in NOX at the entrance to seek a correction value 31. In addition, an estimated rate of variation 33 in NOX at the exit obtained by adding the correction value 31 to a rate of variation 12 in NOX at the exit and the rate of variation 11 in NOX at the entrance are used to seek an actual rate of denitrification 14. Further, the molar ratio correction value mc is sought based on a deviation between the actual rate of denitrification 14 and a set rate of denitrification 16. |
