| 摘要 |
<p>PURPOSE:To minimize discharged dust concentration without increase in GGH corrosion scale by estimating a SO3 concentration indirectly from gas temperatures at an air preheater outlet and a SO2 concentration at a desulfurization inlet, and controlling a lower limit value of dust concentration at an EP outlet in accordance with the estimated value of SO3 concentrations. CONSTITUTION:For instance, data of readings of a thermometer 10 provided at the outlet of an air preheater and an SO2 meter at the inlet of a desulfurization device 5 is entered into an EP dust concentration control device 9. Next, SO3 concentrations are estimated arithmetically in the control device 9 to obtain the lower limit value of dust concentrations which permits maintenance of a required D/S. Then the charge value of a power supply 7 for EP is controlled in such a way that just concentrations measured by means of an EP outlet densitometer 8 are constantly set to the lower limit value. Consequently, operation is possible with EP outlet dust concentrations maintained to the lowest level, while GGH corrosion is held down within a constant range.</p> |
