| 摘要 |
PROBLEM TO BE SOLVED: To obtain a sufficient denitration rate and to reduce leakage ammonia as much as possible, even when operation conditions such as an exhaust gas temperature and an exhaust gas flow rate fluctuate, when performing catalytic reduction of a nitrogen oxide with urea as a reducing agent at a temperature at 200°C or below.SOLUTION: An exhaust gas cleaning method is for supplying urea into a combustion exhaust gas as a reducing agent and performing catalytic reduction to a nitrogen oxide in the exhaust gas under the presence of a denitration catalyst. When an exhaust gas temperature is in the range of 150-250°C, with an urea supply amount when the exhaust gas temperature is fixed as a reference, the urea supply amount is controlled so as to reduce the urea supply amount as the time differential value of the exhaust gas temperature is larger and to increase the urea supply amount as the time differential value of the exhaust gas temperature is smaller. |
