PURPOSE: To keep the decreased level of NO2 concn. independently of the variation in the concn. of products of incomplete combustion, by selecting the positions for injecting ammonia based on the measured concn. of carbon monoxide, residual hydrocarbon, unburned carbon contained in the exhaust gas.
CONSTITUTION: Detecting elements 12 for gas concn. are attached at a flue, or at nests of tubes 3, 7 etc. to measure the concn. are attached at a flue, or at nests of tubes 3, 7 etc. to measure the concn. of reducing materials, e.g., carbon monoxide, residual hydrocarbon, unburned carbon etc. On the basis of the result of the measurement, the quantities of ammonia to be injected through injection nozzles 9, 10, 11 are controlled by an gas analyzer 13 and flow control valves 14, 15, 16. Hereby, efficient denitration is performed according to the charge in composition of the exhaust gas.
KAMIGUCHI TAIJI
OOTA MASAO
