Abstract: The invention relates to a process for preparing at least one aliphatic monoalcohol, generally in excess, and at least one olefin. The process is performed in a distillation and reaction device having a reaction section and a distillation-reaction section. The distillation-reaction section has a distillation zone with at least one means for circulation of the effluent from the reaction section to the distillation zone. Effluent from the reaction section is circulated to the distillation zone. The distillation-reaction section also has at least one distillation-reaction zone having at least one catalyst bed. The distillation-reaction zone is distinct from the distillation zone and provides at least partly the reflux of the distillation zone. The distillation-reaction section can also have at least one complementary reaction zone containing at least one catalyst bed.

Abstract: Disclosed is a process for the resolution of a mixture into at least one first fraction and one second fraction, the respective compositions of said fractions differing by at least one element. The process further comprises at least one elementary stage of fractionation, in which at least two inflows are placed in contact, these two flows being a first inflow (10) with low first fraction content, notably in counter-current, and a second inflow (11) with low second fraction content. Two outflows are obtained, said flows being a first outflow (12) enriched in first fraction with respect to the first inflow (10), and a second outflow (13) enriched in second fraction with respect to the second inflow (11). According to the invention, the elementary fractionation stage, which is non-static, is implemented in an elementary fractionation run, at which point at least one mass exchange buffer supply (15) is accumulated, and the elementary stage of fractionation is periodically initiated and repeated.

Abstract: A process is described for co-producing metaxylene and paraxylene from a hydrocarbon feed comprising two separation steps. The first step of the process is a counter-current simulated moving bed system in a chromatographic column containing at least five zones, comprising injecting the feed and injecting a desorbent and delivering an extract, a raffinate and an intermediate raffinate either continuously or discontinuously. The extract is distilled to obtain a paraxylene with a purity of at least 99.7%. The raffinate, which is richer in metaxylene, is distilled to extract the desorbent and injected into a counter-current simulated moving bed continuously delivering an extract and a raffinate. One of these two streams is enriched in metaxylene. The most metaxylene-rich stream is distilled to obtain metaxylene with a purity of more than 99%.

Abstract: The present invention relates to more or less substituted acrylamide or acrylate and zwitterion monomer hydrosoluble copolymers.

Abstract: For co-production of metaxylene and paraxylene from a hydrocarbon feedstock in a simulated moving bed in a chromatographic column (1) that contains a number of beds 1, 2, 3, 4 . . . of an adsorbent, interconnected in a loop, the column comprises an injection of the feedstock, a draw-off (14) of a first raffinate, a draw-off (17) of a second raffinate that comprises metaxylene, an injection of desorbent and a draw-off of an extract that delivers paraxylene. The injection positions and the draw-off position of the extract are offset periodically by one bed in the direction of flow of the main flux that circulates in the column. First raffinate (14) that comprises desorbent, orthoxylene, metaxylene and ethylbenzene is drawn off continuously or intermittently, and second raffinate (17) R2 that comprises orthoxylene and metaxylene is drawn off intermittently.

Abstract: A process and a device for separating ethane and ethylene from a hydrocarbon steam-cracking effluent is described. Effluent (1) is absorbed in an absorption column (7) by a cooled solvent (9). At the bottom of the column, liquid phase (12) that contains the solvent and the C2+ hydrocarbons is recovered and hydrogenated (15). The hydrogenation effluent that contains the solvent is introduced into a first distillation column (70) where the solvent is regenerated. The solvent is cooled and recycled at the top of absorption column (7). The C2+ hydrocarbons are collected at the top, and a condensed liquid phase is distilled in a second distillation column (77) to recover a C2 fraction that consists of ethane and ethylene.

Abstract: In a process for preparing a catalyst comprising at least one support, at least one metal from group VIII of the periodic table and at least one additional element M selected from the group formed by germanium, tin, lead, rhenium, gallium, indium and thallium, metal M is introduced in an aqueous solvent in the form of at least one organometalic compound comprising at least one carbon-M bond.

Abstract: This invention is a method of conducting seismic prospecting operations using a drilling tool (1) acting at the bottom of a well (2), which creates very powerful seismic vibrations, transmitting reference signals representing the vibrations of the tool in real time or later, and correlating the seismic signals picked up by a receiving assembly (12) with the reference signals. The reference signals are furnished by sensors (7) in contact with the drill string and at a distance from the down-hole assembly constituted by tool (1) and associated drill collars (4). In order for these reference signals to be truly representative, a damping means (8, 19) and at least one filtering element (20) designed to attenuate to a great degree the multiple reflections in a frequency range useful for seismic prospecting are interposed into the drill string. The invention has application to the making of seismic recordings.

Abstract: The pore-size distribution of a porous sample of variable porosity is modeled achievement of, allowing laboratory studies on the behavior of the medium modeled in relation to fluids. The porosity of the porous medium is modeled on one or more parting surfaces by means of a network (R) of intersecting channels (C) whose nodes form pores (P), the size of these channels showing physical properties of the medium and being selected from one or more discrete channel size distributions. In order to model the porosity of a heterogeneous sample exhibiting very different porosity zones, several discrete channel distributions are preferably used, these distributions being disjoint or not, and modeling with different zones, zones of low permeability and zones of higher permeability.

Abstract: The present invention relates to a method for predicting and controlling the hydrogen corrosion and embrittlement behavior of steels in the presence of H2S. In the method, at least the following stages are carried out: determining a characteristic value l0 which is a function of the proportion of dislocations present in the lattice of a first steel sample treated under hardening conditions such that, after the hardening treatment, by quenching and tempering or by work hardening, the hardness of said steel reaches a maximum value at a threshold stress &sgr;threshold such that &sgr;threshold equals k·Rp0.2 k being less than or equal to Rp0.

Abstract: A novel catalyst for transforming organic compounds is described. The catalyst is composed of a support selected from refractory oxides such as aluminas, silicas, silica-aluminas or magnesia, used alone or as a mixture, a group VIII metal such as palladium, associated or not associated with another metal, said catalyst being such that the volume of chemisorbed carbon monoxide is greater than or equal to 180 cm3 per gram of metal and has a programmed temperature reduction profile comprising a single hydrogen consumption peak.

Abstract: A steam-cracking process includes the injection, at at least one point upstream from a secondary quenching indirect exchanger (4b), of particles with a mean size of between 0.02 and 4 mm, at a velocity speed in the exchanger of 20 to 180 m/s, in sufficient quantity to limit the rise in the output temperature of the effluents from the exchanger to a value that is less than 100° C. per month. At least 70% by weight of the quantity of injected particles is introduced downstream from primary quenching exchangers (4a) and upstream from the inlet to the secondary quenching exchanger. At intervals, decoking of the pyrolysis pipes and primary quenching exchangers is carried out in the presence of air.

Abstract: A system intended for permanent installation of measuring sondes against the inner wall of a pipe (1) such as a well or a tube. Measuring sondes (7) are respectively associated with coupling devices (2) that are brought to their respective coupling points in the pipe by means of a tube (3) positioned by off-centering devices (4) for example. Each coupling device (2) comprises a flexible element (6) carrying sonde (7), that is deformed to a set back position where it is immobilized by a lock (9) so as to allow displacement thereof along pipe (1). In order to release flexible blades (6), a sufficient overpressure allowing to push back the piston of a jack (10) whose cylinder communicates at one end with the inside of pipe (1) is established. In this expanded position, it immobilizes coupling device (2) and presses sonde (7) against pipe (1) while mechanically decoupling it from tube (3). Tube (3) can possibly be withdrawn if it does not serve another purpose.

Abstract: A process for the production of a controlled supported zeolite membrane comprises: (a) forming a gel which is principally localised at the surface of a porous support by bringing it into contact, in succession, with two immiscible liquids which contain the agents necessary for formation of said gel, then (b) crystallising the zeolite from said gel and finally (c) eliminating the residual agents. The supported zeolite membranes obtained are advantageously used in continuous gas separation processes.

Abstract: A process for production of paraxylene from a charge containing C7-C9 aromatic hydrocarbons in which a first fraction is enriched to at least 30% weight with paraxylene and this fraction is purified by at least one high-temperature crystallization in at least one crystallization zone. Said first fraction is crystallized in a crystallization zone at high temperature T1 and advantageously between +10 and -25.degree. C., crystals in suspension in a mother liquor are recovered, the crystals are separated from the mother liquor in at least a first separation zone, the crystals obtained are partially melted in at least a zone for partial melting and a suspension of crystals is recovered, the crystals in suspension are separated and washed in at least one separation and washing zone and pure paraxylene crystals and washing liquor are recovered, and pure crystals are optionally completely melted and a liquid stream of melted paraxylene is collected.

Abstract: A method which enables the sulphur and/or hydrogen contained in a low quantity in hydrogen sulphide to be prepared:1) the H.sub.2 S is oxidized at a temperature and for a duration selected to obtain full oxidation of the H.sub.2 S into SO.sub.2 and at least two products are obtained at the end of this step: SO.sub.2 and H.sub.2 O,2) The two products SO.sub.2 and H.sub.2 O obtained at the end of step 1) are separated,3) the isotope of the sulphur contained in the sulphur dioxide obtained during step 2) is measured and/or4) the H.sub.2 O obtained during step 2) is brought into contact with an agent capable of reducing the water to hydrogen form and5) the isotope of the hydrogen is measured.

Abstract: A reinforced flexible tube having at least one helically wound elongated reinforcing element. The elongated reinforcing element has a T-shaped cross-sectional profile.

Abstract: A method of determining the position in subsoil of a population of physical phenomena linked with physical properties of the subsoil. Data are collected, for example, subsoil exploration or in-situ measurements. The phenomena are marked by points in a multivariate space and defined by an attribute vector, the coordinates of each of the points being attributes associated with the phenomena, using a function expressing a multivariate probability law appropriate for the population. Modes corresponding to higher density zones of the function are selected, the number of modes giving a number of potential losses in the population of the phenomena. For each mode a set of selected point marks the most representative events of each class. A classifying function is determined from the selected points, and the probabilities of non-selected points belonging to each of the potential classes is determined by using the determined classifying functions.

Abstract: Method of liquefying a natural gas wherein a first coolant mixture M.sub.1 is used for the first cooling stage and a second coolant mixture M.sub.2 for the second cooling stage, said mixture M.sub.2 being cooled in the first cooling stage by means of the first coolant mixture (by vaporization after expansion) in order to obtain a condensed, single-phase mixture M.sub.2 at the outlet and in that mixture M.sub.2 is vaporized to cool the second cooling stage at least partially.

Abstract: A process for the pyrolysis of hydrocarbons in a reactor with at least two rows which are parallel to each other in which at least one row is supplied with a non hydrocarbon fluid containing steam to decoke the reaction zone at least in part. At least one other row is supplied with a gaseous mixture containing at least one hydrocarbon and water, to pyrolyze said mixture.