| 摘要 |
<p>PROBLEM TO BE SOLVED: To quickly control the feed rate of a desalting agent and to stabilize the concentration of HCl in exhaust gas at a low level in a desalting treatment of an exhaust gas generated when incinerating wastes. SOLUTION: The control system for controlling the feed rate of the desalting agent is based on the [P+PID] control and constituted of a bag filter 30, a HCl analyzer 31 and controllers 32 and 33, an adder 34, a desalting agent feeding device 35 or the like. The operation signal MVI calculated by PID operation from the concentration PV of HCl in the treated exhaust gas 37 and an arbitrary preset value SV1 is added to the operation signal MV2 calculated by P operation from the concentration PV of HCl and an arbitrary preset value SV2, and the prescribed amount of the desalting agent is fed to the exhaust gas 36 to be treated from the desalting agent feeding device 35 according to the control output (MV1+MV2). The preferable desalting agent is a highly reactive desalting agent such as a fine powder of sodium bicarbonate. In this method, the highly reactive desalting agent is properly fed, and especially, the control response is made quick when the feed rate of the desalting agent is increased. Thereby, the concentration of HCl in the treated exhaust gas is stabilized at a low level.</p> |
