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: Microprogrammed computing device comprising a data processing system, a central memory operatively connected thereto, means for exchanging data with peripheral devices, a system for controlling the execution of orders issued from the memory, a system for hierarchically classifying the tasks in a list and making the processing system available for the task having the first priority and a system for managing said list, means for testing the availability of said peripheral devices and means for adapting the processing system to each new task to which the first priority is given, whereby several computing and data exchange processes may be performed by the same device.

Abstract: New catalyst, particularly suitable for dehydrogenating saturated hydrocarbons, which contains alumina, at least one metal selected from molybdenum, tungsten and rhenium and at least one metal selected from gallium, indium, thallium, germanium, tin, lead, antimony and bismuth, said catalyst having a specific surface from 20 to 150 m.sup.2 /g and a neutralization heat by ammonia absorption at 320.degree.C under 300 mm Hg lower than 10 calories per gram.

Abstract: The composition is constituted by a mixture of Lewis acid corresponding to the formula MXm where:M is an atom of a metal belonging to Groups IV, V and VI of the Periodic Table of Elements,X is a halogen,m is within the range of 3 to 6,And a sulphonic acid corresponding to the general formula RF(SO.sub.3 H)p where RF represents a perfluorinated alkyl or cycloalkyl hydrocarbon radical having a number of carbon atoms ranging from 2 to 8 and p is 1 or 2.

Abstract: In order to analyze gaseous compounds of a mixture which have a mass below a given value, a fraction containing a number of phases is continuously sampled in a loop mounted in parallel with a main circuit under conditions of pressure such that the Reynolds numbers in the main circuit and the sampling loop are equivalent. The mixture is passed through traced pipes, at least one dust remover and at least one heat exchanger in which a heat-transporting fluid is circulated at an adjustable temperature T.sub.1 ; condensed and gaseous fractions of the mixture are collected in a flash drum placed in an enclosure at an adjustable temperature T.sub.2 ; the products of the mixture are then passed to an analytical instrument, their mass being such that they are in gaseous form at the temperature T.sub.2.