| 摘要 |
<p>Heat balance of a fractionation column is controlled and maintained by obtaining three differential temperatures between selected temperature-sensing points along the height of the column. A signal representing one of the delta-T's is employed in regulating the quantity of reflux returned to the rectification zone. The remaining two delta-T's are conjunctively utilized to regulate the enthalpy (heat-input content) of the reboiled liquid bottoms stream being returned to the reboiler section of the column. With respect to the latter, a selected one of the two delta-T signals is multiplied by a multiplier representing the ratio of the number of trays between the temperature sensing points supplying the non-selected delta-T signal to the number of trays between the temperature sensing points supplying the selected delta-T signal. A signal representing the resulting product is correlated with the non-selected signal, and the signal representing the resulting relationship is utilized to regulate the degree to which the returned liquid bottoms material is vaporized.</p> |
