| 摘要 |
<p>PURPOSE:To reduce the power consumption in operating a flue gas desulfurization apparatus by computing a requirement signal derived from a real and requested desulfirization degrees, the former of which is calculated from measured values of sulfur oxide concentrations in flue gas at the inlet and outlet of that apparatus and the latter is calculated specifically, and controlling a flow rate of circulating steam through an absorption tower based on that signal. CONSTITUTION:Both SO2 concentrations 48 and 47 of flue gas at the inlet and outlet of a desulfurization apparatus, which are measured with respective gas analyzers 26 and 23, are entered into a subtracter 28 and the result of subtraction is entered into a divider 29. A dividing calculation is then performed with the result of this subtraction as a numerator and the inlet SO2 concentration 48 as a denominator and a real desulfirization rate 44, the answer of this calculation, is sent to a controller 24. On the other hand, a requested outlet SO2 concentration 49, which is set with an SO2 concentration setter 27, and the inlet SO2 concentration 48 are entered into a subtracter 30 and the result of subtraction is entered into a divider 31. A dividing calculation is performed with the result of this subtraction as a numerator and the inlet SO2 concentration as a denominator and a requested desulfurization rate, the answer of this calculation, is also sent to the controller 24. Next, a difference between the requested desulfurization degree 46 and the real one 44 is calculated and a requirement signal 50, which proportionally controls a flow rate of circulating stream through a absorption tower of the desulfurization apparatus based on the aforementioned difference, is sent to a control valve 25. The flow rate of circulating stream is thus controlled.</p> |
