| 摘要 |
<p>PURPOSE:To prevent the hazard of explosion and to enhance the efficiency of reaction by introducing an appropriate amount of diluting air required for denitration reaction by a method wherein there are provided a valve for adjusting the flow rate of the diluting air and an amplifier amplifying the instruction of the flow rate of NH3 gas. CONSTITUTION:Total NOx amount 1-d is calculated by multiplying the flow rate 1-a of dry exhaust gas of a boiler by NOx concentration 1-b at the outlet of the boiler. The value 1-d is compared with the flow rate 1-c of NH3 gas introduced into a demitration apparatus. Subtraction is made to obtain the value 1-f. According to the resulting value 1-f, an instruction from a control meter 1-h is given and the flow rate of NH3 gas is controlled by an adjusting valve 1-i. At the same time, the output of the control meter 1-h is amplified by an amplifier 1-j. The flow rate of diluting air is controlled by an adjusting valve 1-e to which an amplified output is given, thereby a mixing ratio of NH3 to air is brought constant. As there will be the danger of explosion when the mixing ratio becomes below the lower limit of explosion, the mixing ratio is controlled by basing on safety factor.</p> |
