Abstract: The method consists in preparing from the crude petroleum being processed a representative cut constituting a vaporized fraction having a known yield, in plotting the TBP curve of the cut by chromatographic analysis and by integration of the quantitative signal produced as a result of the analysis. The information obtained from the analysis is processed in order to operate a control unit for generating signals which serve to adjust the rates of withdrawal of the cuts at different predetermined levels of the column.

Abstract: Adjustment and control of a product fraction stream and especially gas oil are effected by a control unit after processing information supplied by an analyzer which takes a direct measurement of the temperature of filtrability of the stream and by detectors which deliver signals representing the flow rate of the gas oil withdrawn, the rate of withdrawn of the next higher product stream, the flow rate of the crude petroleum being processed, the flow rate of the stripping vapor and of the next lower product stream, and the slope of the distillation curve of the crude petroleum in the gas oil zone.

Abstract: A sampling circuit connected directly to the distillation column consists of a primary loop formed by a sampling tube which penetrates into the column in a region of expansion and vaporization and is equipped with means for limiting the velocity of the vapor collected therein and for separating the entrained liquid fraction if necessary. The sampling circuit further comprises a condenser and a filter, the condensate being returned to the column by a circulating pump and a withdrawal of condensate being effected by a secondary loop for supplying an analyzing device in parallel.