| 摘要 |
PURPOSE:To automatically control the title equipment through an improvement in the heat recovery and a reduction in the number of working steps, by calculating the amt. of a circulating gas flowed so far from the heat balance of a boiler and conducting a particular computation to automatically control the flow rate of the circulating gas. CONSTITUTION:The inlet temp. and the outlet temp. of a boiler 34 are measured with a detector 43 and a detector 44, respectively. Further, the feed water temp. is measured with a detector 46, the main steam temp. with a detector 47, the main steam pressure with a detector 48, the main steam flow rate with a detector 49, the discharge amt. of powdery coke in a cyclone with a detector 52, the difference in pressure before and after a circulating fan with a detector 53, and the difference in pressure between the outlet and inlet of a cooling tower with a detector 54. Each detected value and the value of components detected with a gas analyzer 56 are transmitted to a control computer 55, where the amt. of the circulating gas flowed so far is calculated from the heat balance of the boiler 34. An approximate expression is prepared with respect to the relationship between the flow rate of the circulating gas and the degree of opening of a circulating damper. The expression is automatically corrected in a proper manner according to the latest detected process data to prepare a corrected approximate expression. A necessary flow rate of the circulating gas is determined from the corrected approximate expression and the preset value of the amt. of coke discharged by manual operation. A circulating damper 36, a recovery control valve 41, and a diluting air flow rate control valve 39 are automatically operated based on the determined necessary circulating gas flow rate.
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