| 摘要 |
<p>PURPOSE: To prevent the outflow of excessive ammonia by sensing the outlet NOx concentration for respective systems and correcting the injected ammonia molar ratio based on the deviation between the sensed value and the outlet NOx concentration set value. CONSTITUTION: In a system in which exhaust gas exhausted out of a boiler 1 to denitration reactors 8 and 9 for respective systems through a gas flue of two systems and the denitration treatment is carried out, samplings 10 and 11 of exhaust gas on the downstream side of denitration reactors of respective systems are carried out respectively, and a mixed body of exhaust gas in both systems is fed to an outlet NOx concentration meter 13 and the average outlet NOx concentration is sensed. Based on the sensed values of inlet NOx concentration meters 2 and 3 for respective systems, the set value of an outlet NOx concentration setting device and the average outlet NOx concentration, the injected ammonia molar ratios for respective systems are computed. Based on the injected ammonia molar ratios and the exhaust gas flow rate, flow rate regulating valves 4 and 5 are controlled to control the injected ammonia amount for respective systems.</p> |
