Abstract: The electrodesulfurization of heavy oils wherein a feedstream comprised of bitumen or heavy oil is conducted, along with an effective amount of hydrogen, to an electrochemical cell. A current is applied to the cell wherein sulfur from the feedstream combines with hydrogen to form hydrogen sulfide which is removed.

Abstract: The electrodesulfurization of heavy oil feedstreams is accomplished wherein a heavy oil feedstreams, along with hydrogen, is passed the cathode side of an electrochemical cell wherein the organically bound sulfur compounds in the heavy oil are reduced and the sulfur is released as hydrogen sulfide. The hydrogen sulfide can be fed directly into the anode side of the electrochemical cell to produce sulfur and hydrogen or it can be passed to an oxidation zone containing an aqueous solution of an oxidized metal salt.

Abstract: An integrated process for the hydroprocessing of multiple feedstreams including vacuum gas oil and light cycle oil. The light cycle oil is reacted with hydrogen in a hydrocracking zone and the hydrocarbon feedstream comprising vacuum gas oil is reacted with hydrogen in a hydrodesulfurization reaction zone. The hydrotreated vacuum gas oil is good FCC feedstock. Naphtha and ultra low sulfur diesel are recovered in a common fractionation column.

Abstract: A process for denitrogenating diesel fuel includes contacting diesel fuel containing one or more nitrogen compounds with an acid ionic liquid in an extraction zone to selectively remove the nitrogen compound(s) and produce a denitrogenated diesel fuel effluent containing denitrogenated diesel fuel and acid ionic liquid containing nitrogen species; and separating denitrogenated diesel fuel from the denitrogenated diesel fuel effluent.

Abstract: The present invention is a method of removing sulphur from a hydrocarbon feed stream, comprising the steps of: (a) dissolving sodium in a liquid solvent to form a solution containing sodium atoms; (b) combining the liquid solution from step (a) with a liquid hydrocarbon feed containing an organosulfur component to form a combined stream at a temperature of addition and at a pressure near or above the vapor pressure of the solvent at the temperature of addition; (c) reacting the combined stream for sufficient reaction time and at sufficient reaction temperature to form a modified composition comprising one or more sulfur-containing species and less of the organosulfur species than had been present in the hydrocarbon feed; (d) extracting a portion of the sulfur-containing species from the modified composition.

Abstract: The invention relates to a process and installation for treating heavy petroleum feedstocks for producing a gas oil fraction that has a sulfur content of less than 50 ppm and most often 10 ppm that includes the following stages: a) mild hydrocracking in a fixed catalyst bed, b) separation from hydrogen sulfide of a distillate fraction that includes a gas oil fraction and a heavier fraction than the gas oil, c) hydrotreatment (including desulfurization) of said distillate fraction, and d) separation of a gas oil fraction with less than 50 ppm of sulfur. Advantageously, the heavy fraction is sent into catalytic cracking. The process preferably operates with make-up hydrogen that is brought to stage c), and very advantageously all of the make-up hydrogen of the process in introduced in stage c).

Abstract: An object of the present invention is to provide a catalyst for hydrodesulfurization/dewaxing of a hydrocarbon oil, with which sulfur compounds in the hydrocarbon oil can be desulfurized to a high degree and which simultaneously is extremely effective in reducing the wax deposit content; a process for producing the catalyst; and a method of hydrotreatment with the catalyst. The invention relates to a catalyst for hydrodesulfurization/dewaxing of a hydrocarbon oil, comprising a support comprising an inorganic oxide containing at least one crystalline aluminosilicate having a one- or two-dimensional pore path system and, having provided thereon, 10 to 35% by mass of a metal in Group 6 of the Periodic Table, 1 to 10% by mass of a metal in Group 8 of the Periodic Table, and 1.

Abstract: A desulfurization system is operated in a manner which optimizes sulfur removal and octane retention. When the desulfurization reactor is operated at a specific ratio of total pressure to hydrogen partial pressure (PT/PH) and/or within a specific temperature range, optimum sulfur removal and octane retention are realized. The desulfurization reactor can be maintained at these optimized operating conditions by automatically adjusting one or more operating parameters of the desulfurization reactor in order to maintain a substantially constant hydrogen partial pressure (PH) in the reactor. Maintaining a relatively constant hydrogen partial pressure (PH) in the desulfurization reactor helps ensure a relatively consistent degree of desulfurization.

Abstract: A method for hydrodesulfurization by forming a dispersion comprising hydrogen-containing gas bubbles with a mean diameter of less than 1 micron dispersed in a liquid phase comprising sulfur-containing compounds. Desulfurizing a liquid stream comprising sulfur-containing compounds by subjecting a fluid mixture comprising hydrogen-containing gas and the liquid to a shear rate greater than 20,000 s?1 to produce a dispersion of hydrogen in a continuous phase of the liquid and introducing the dispersion into a fixed bed hydrodesulfurization reactor from which a reactor product is removed. Systems of apparatus for hydrodesulfurization are also presented.

Abstract: An integrated process for the production of low sulfur diesel. The process utilizes a middle distillate hydrocarbon stream and a heavy distillate hydrocarbon stream. The middle distillate hydrocarbon feedstock is reacted with a hydrogen rich gaseous stream having a first pressure in a hydrodesulfurization reaction zone and the heavy distillate hydrocarbon feedstock is reacted with a hydrogen rich gaseous stream having a second pressure in a hydrocracking zone.

Abstract: A method for removal of corrosive compounds from insulating oil. The insulating oil is exposed to at least one reducing agent.

Abstract: A two-stage hydrotreating process is disclosed wherein a hydrocarbon stream is first desulphurized followed by a dehydrogenation step, which process comprises in combination contacting the feed and hydrogen over a hydrotreating catalyst at hydrotreating conditions, heating the hydrotreated effluent and hydrogen-rich gas from the hydrotreating reactor and contacting said effluent and hydrogen gas over a hydrotreating catalyst in a post-treatment reactor at a temperature sufficient to increase the polyaromatic hydrocarbon content and lower the hydrogen content of said effluent.

Abstract: Naphtha hydrodesulfurization selectivity is increased by reducing the amount of COX (CO plus ½ CO2) in the hydrodesulfurization reaction zone to less than 100 vppm. While this is useful for non-selective hydrodesulfurization, it is particularly useful for selectively desulfurizing an olefin-containing naphtha without octane loss due to olefin saturation by hydrogenation. The COX reduction is achieved by removing COX from the treat gas before it is passed into the reaction zone.

Abstract: A hydrocracking process wherein the feedstock is hydrotreated and the liquid and gaseous effluent from the hydrotreater is directly introduced into the upper end of a hydrocracking vessel which provides a liquid seal to prevent the passage of the gaseous stream containing hydrogen sulfide and ammonia from the hydrotreater to enter the hydrocracking zone containing hydrocracking catalyst. Fresh hydrogen is then introduced into the hydrocracking zone. An apparatus for hydrocracking a hydrocarbon feedstock is also disclosed.

Abstract: A process for upgrading a residua feedstock using a short vapor contact time thermal process unit comprised of a horizontal moving bed of fluidized hot particles. The residua feedstock is preferably atomized so that the Sauter mean diameter of the residua feedstock entering the reactor is less than about 2500 ?m. One or more horizontally disposed screws is preferably used to fluidize a bed of hot particles.

Abstract: A process for the production of low sulfur diesel and high octane naphtha.

Abstract: After passing into reaction section R, the hydrocarbon feedstock C mixed with hydrogen H is expanded in device D. The expansion is brought about by a single-phase turbine until a gas volume ratio of 5% is reached, then expansion is brought about in a two-phase turbine of the rotodynamic type.

Abstract: A method for thermally cracking a hydrocarbonaceous feed material using a combustion fuel fired furnace wherein at least part of the combustion fuel employed in the furnace is syngas.

Abstract: The present invention is related to a method of subjecting a feed oil to a refining process. This method includes a fractional distillation step 1 in which a feed oil is separated into a distillate oil M1 and a bottom oil M2 by a distillation process, a separation step in which the bottom oil is separated into a bottom light oil and a residue, and a hydrorefining step 3 in which the obtained distillate oil M1 and the bottom oil M2 are subjected to hydrorefining in the presence of hydrogen and a catalyst. In the hydrorefining step 3, the bottom light oil (deasphalted oil M3) is passed through a first catalyst layer 12 of a hydrorefining unit providing a plurality of catalyst layers 12, 13, and 13 filled with a hydrorefining catalyst, and a mixed oil comprising the distillate oil M1 and the bottom light oil (deasphalted oil M3) is passed through a downstream catalyst layer 13 and subject to a hydrogenation process.

Abstract: A process for the hydrodesulfurization of cracked olefin streams is described, the process aiming at reducing the sulfur content while at the same time minimizing the hydrogenation degree of said olefins. In order to dilute the added reaction hydrogen, the process makes use of non-reactive compounds such as N2, CH4, C2H6, C3H8, C4H10, Group VIII noble gases as well as admixtures of same in any amount, in gas or vapor phase.

Abstract: Process for desulfurization of an effluent for cracking or steam-cracking hydrocarbons, more particularly a gasoline for example for catalytic cracking that comprises the elimination of thiophenic compounds by alkylation of these compounds, followed by a distillation, a hydrocracking of said alkyl-thiophenic compounds, then a hydrodesulfurization of the effluent that is obtained from the hydrocracking zone. In a preferred embodiment, this process comprises a preliminary stage for separating the cracking or steam-cracking effluent into three fractions, and proposes sending to the alkylation stage only the intermediate fraction that is low in heavy basic nitrogen-containing compounds that are initially present in the effluents that are to be alkylated.

Abstract: A catalyst and process is disclosed to selectively upgrade a paraffinic feedstock to obtain an isoparaffin-rich product for blending into gasoline. The catalyst comprises a support of a sulfated oxide or hydroxide of a Group IVB (IUPAC 4) metal, a first component of at least one lanthanide element or yttrium component, which is preferably ytterbium, and at least one platinum-group metal component which is preferably platinum.

Abstract: Contact, mixing, and often quenching box (8), with main dimension (D) and height (H7), comprising at least one duct section (B1) located on the upper part of said box (8) for entry of fluids in which said box (8) comprises, downstream from said duct section (B1), in the direction in which the fluids circulate, a means (B4) that provides, in said box (8), for making the fluids swirl in an approximately nonradial direction, and not parallel to the overall direction of circulation of said fluids, and comprising at least one annular, peripheral duct section (B6) for the exit of said mixture of fluids formed in said box (8) whose lower level is located above the upper level for fluid entry through at least one lateral inlet (B3) located in said box (8) above means (B4). A reaction cell (4), of an elongated shape along an approximately vertical axis comprising the contact, mixing, and quenching box (8) is useful for performing exothermic reactions.

Abstract: A process for hydrodesulphurizing gasoline cuts is carried out in the presence of a catalyst comprising at least one group VIII element, at least one group VIB element, and a support with a specific surface area of less than about 200 m2/g, wherein the density of the group VIB elements per unit surface area of the support is in the range 4×10?4 to 36×10?4 g of group VIB element oxides per m2 of the support.

Abstract: A process for preparing high VI lubricating oil basestocks comprising hydrotreating, hydrodewaxing and optionally hydrofinishing. The hydrotreating step is under conditions such that the amount of conversion to 343° C. minus is less than 5 wt. % of the feedstock and the VI increase is less than 4 VI over the feedstock. Hydrodewaxing uses a low alpha catalyst and hydrofinishing is accomplished with a catalyst based on the M41S family.

Abstract: The process for desulfurizing a gas oil fraction according to the invention comprises a low-boiling gas oil fraction hydrodesulfurization step (I) wherein a low-boiling gas oil fraction is desulsurized under the condition of a H2/Oil ratio of 70 to 200 Nm3/kl to obtain a treated oil, a high-boiling gas oil fraction hydrodesulfurization step (II) wherein a high-boiling gas oil fraction is desulsurized under the condition of a H2Oil ratio of 200 to 800 Nm3/kl to obtain a treated oil, and a step (III) wherein the treated oil obtained in the step (I) is mixed with the treated oil obtained in the step (II), and in this process, at least a part of a gas containing unreacted hydrogen in the step (II) is used for the hydrodesulfurization of the step (I).

Abstract: A process for removing organic sulfur compounds from heavy boiling range naphtha in a dual purpose reactor wherein the heavy boiling range naphtha is fed downflow over a fixed bed of hydrodesulfurization zone and then treated with hydrogen in a hydrodesulfurization catalytic distillation zone. Vapor containing hydrogen sulfide is removed between the zones. Preferably the heavy boiling range naphtha is produced by treating a full boiling range naphtha to concurrently react diolefins and mercaptans and split the light and heavy boiling range naphtha in a distillation column reactor.

Abstract: A process for removing sulfur from hydrocarbon feeds, including the steps of providing a hydrocarbon feed containing sulfur; providing a cell having two compartments and a membrane separating the compartments; flowing a hydrogen source through one compartment; flowing the hydrocarbon feed through the other compartment; applying a current across the hydrogen source compartment whereby hydrogen diffuses through the membrane from the hydrogen source to the hydrocarbon feed, whereby the hydrogen reacts with sulfur to form H2S and produce a treated hydrocarbon.

Abstract: A process to continuously prepare a hydrocarbon product having a specified desired sulphur content lower than 0.05 wt %, starting from at least two or more high-sulphur hydrocarbon feedstocks having a sulphur content of above 0.

Abstract: A device located between two successive granular beds (203) and (205) for injecting a secondary fluid can produce and distribute a polyphase mixture between said secondary fluid and a fluid or mixture of fluids originating from the upper granular bed and comprises a chamber for injecting a secondary fluid (201), the secondary fluid being injected into said device, and means (204) for bringing said secondary fluid into contact with at least a portion of the fluid or mixture of fluids originating from the upper granular bed (203) and for simultaneous distribution (208) of the mixture resulting from said contact to the lower granular bed (205).

Abstract: The invention is directed to a catalyst suitable for the hydrogenation of hydrocarbon resins, comprising a supported nickel on silica and alumina catalyst, said catalyst having a nickel content of 45 to 85 wt. %, a silicon content, calculated as SiO2, of 14 to 45 wt. %, an aluminium content, calculated as Al2O3, of 1 to 15 wt. % an iron content, calculated as Fe, 0.25 to 4 wt. %, all percentages having been calculated on the basis of the reduced catalyst, and which catalyst has a volume of pores between 2 and 60 nm, as defined herein, of at least 0.35 ml/g of catalyst.

Abstract: The invention is a method of removing sulfur from a hydrocarbon feed using the steps of dissolving metallic sodium in a solvent and combining the sodium/solvent solution with a liquid hydrocarbon feed containing an organosulfur species. The pressure of combination is above the vapor pressure of the solvent. The combined hydrocarbon feed and solvent solution are placed in a low pressure environment to vaporize the solvent. The resulting stream is combined with hydrogen gas and this stream is heated and pressurized to form a liquid hydrocarbon product containing sodium sulfide. This product is then cooled, and the sodium sulfide is extracted.

Abstract: The present invention relates to a catalytic composition which comprises a beta zeolite, a metal of group VIII, a metal of group VI B and optionally one or more oxides as carrier. The catalytic system of the present invention can be used for the hydrotreating of hydrocarbon mixtures and more specifically in the upgrading of hydrocarbon mixtures having boiling ranges within the range of 35° to 250° C., containing sulfur impurities, i.e. in hydrodesulfuration with contemporaneous skeleton isomerization and a reduced hydrogenation degree of olefins contained in said hydrocarbon mixtures, the whole process being carried out in a single step.

Abstract: A process for producing food grade wax which contains exceedingly low levels of nitrogen, sulfur and aromatic compounds. A waxy feedstock is firstly hydrotreated in a first hydrogenation zone to reduce the level of contaminants such as sulfur, nitrogen and aromatic compounds, and the resulting effluent from the first hydrogenation zone is introduced into a hot, high pressure stripper and contacted with a hot, hydrogen-rich stripping gas to remove ammonia and hydrogen sulfide. The stripped, hot liquid hydrocarbons are removed from the bottom of the hot, high-pressure stripper to further reduce the concentration of aromatic compounds by being hydrogenated in a second hydrogenation zone containing a platinum or palladium catalyst.

Abstract: A process for reducing sulfur compounds in naphtha to produce gasoline of ultra-low sulfur content, i.e., 10–30 ppm of sulfur, from a fluidized catalytic cracking reactor effluent stream, withdraws a high sulfur content sidestream of catalytically produced medium and heavy cat naphtha with an endpoint of +430° F. that is fed to a side column where any thiophenic and benzothophenic compounds are catalytically reacted with hydrogen to convert them to hydrogen sulfide. The desulfurized light and mid-cut naphtha is returned to the main fractionation unit and the heavy catalytic naphtha is withdrawn as a product stream from the bottom of the side column.

Abstract: A cooling method of a hydrotreating plant having a desulfurization section (1) including a furnace (12) for heating liquid to be processed, reactors (14, 15) for hydrotreating sulfur to generate hydrogen sulfide, a hydrogen sulfide absorber (19) for absorbing the hydrogen sulfide generated in the reactors (14, 15), and a compressor (21) for compressing and transferring fluid from the hydrogen sulfide absorber (19) toward the reactors (14, 15), the cooling method comprising the steps of gradually depressurizing the hydrotreating plant at the desulfurization section (1) to a pressure level at which reactor material does not embrittle and gas does not leak due to difference of mechanical thermal expansion in the plant after stopping supply of the liquid to be processed, operating the compressor (21) approximately at the maximum rotation number, and completely extinguishing burners (12A, 12B) in the furnace (12) during plant shutdown operation.

Abstract: A catalytic hydrocracking process for the production of ultra low sulfur diesel wherein a hydrocarbonaceous feedstock is hydrocracked at elevated temperature and pressure to obtain conversion to diesel boiling range hydrocarbons. The resulting hydrocracking zone effluent is hydrogen stripped in a stripping zone maintained at essentially the same pressure as the hydrocracking zone to produce a first gaseous hydrocarbonaceous stream and a first liquid hydrocarbonaceous stream. The first gaseous hydrocarbonaceous stream containing diesel boiling range hydrocarbons is introduced into a desulfurization zone and subsequently partially condensed to produce a hydrogen-rich gaseous stream and a second liquid hydrocarbonaceous stream containing diesel boiling range hydrocarbons. The first liquid stream is separated to produce a third liquid hydrocarbonaceous stream containing diesel boiling range hydrocarbons which is also introduced into the desulfurization zone. An ultra low sulfur diesel product stream is recovered.

Abstract: A process wherein all of the unsaturates within a cracked naphtha stream are substantially hydrogenated to alkanes and the olefin depleted stream is then subjected to hydrodesulfurization to achieve the desired sulfur levels without the formation of recombinant mercaptans.

Abstract: Structured catalysts comprising thick porous inorganic catalyst support coatings disposed on monolithic catalyst support structures, the support coatings having open interconnected porosities of controlled pore size but being characterized by improved durability, physical integrity, and adherence sufficient for use in liquid phase applications under harsh reaction conditions, and methods for making and using them, are disclosed.

Abstract: The invention relates to a process for the production of gasoline with a low sulfur content comprising at least three stages: a first stage in which the sulfur-containing compounds present in the gasoline are at least partially transformed into H2S and into saturated sulfur-containing compounds; a second stage whose purpose is to eliminate the H2S from the gasoline produced in the first stage; and a third stage in which the saturated sulfur-containing compounds remaining in the gasoline are transformed into H2S. The process according to the invention optionally also comprises a pretreatment stage whose purpose is to hydrogenate the diolefins of the feedstock before the first stage.

Abstract: A process for concurrently fractionating and hydrotreating of a full range naphtha stream. The full boiling range naphtha stream, for example which is derived from fluid catalytic cracking, is first subjected to simultaneous hydrogenation of the thiophene contained therein and thioetherification and fractionation to remove the mercaptans the light fraction and then to simultaneous hydrodesulfurization and splitting of the bottoms into an intermediate boiling range naphtha and a heavy boiling range naphtha. The three boiling range naphthas are treated separately according to the amount of sulfur in each cut and the end use of each fraction.

Abstract: A navigation system, portable information processing device and its control program, data server, information processing server, navigation method, traveling route establishing method, information providing method, and area information providing method are disclosed having a portable terminal (10,54,210) to read out code data, indicative of area information of a destination and routed spots, from a print product (112,114). The code data are converted into area information and stored in a storage unit (23,66,72,123,223,232,323), from which particular area information is retrieved and transmitted to an on-vehicle navigation device (30,58,104,230) by which a traveling route of the vehicle is established on the basis of area information to guide the vehicle to the destination.

Abstract: A process for the selective hydrodesulfurization of olefinic naphtha streams containing a substantial amount of organically bound sulfur and olefins. The olefinic naphtha stream is selectively hydrodesulfurized in a first sulfur removal stage and resulting product stream, which contains hydrogen sulfide and organosulfur is fractionated at a temperature to produce a light fraction containing less than about 100 wppm organically bound sulfur and a heavy fraction containing greater than about 100 wppm organically bound sulfur. The light fraction is stripped of at least a portion ofits hydrogen sulfide and can be collected or passed to gasoline blending. The heavy fraction is passed to a second sulfur removal stage wherein at least a portion of any remaining organically bound sulfur is removed.

Abstract: The invention relates to: a process for the desulphurization of feed streams comprising: supplying a hot process stream to a lead catalyst bed (8) comprising a first sulphur-removing catalyst and a second sulphur-removing catalyst under conditions whereby sulphur is removed from the process stream by the first sulphur-removing catalyst and said second sulphur-removing catalyst does not effectively remove sulphur from the stream at the operating temperature of the lead catalyst bed for the duration of the bed's life; collecting a hot partially sulphur-depleted stream from the lead catalyst bed and cooling said stream; passing said cooled stream through a lag catalyst bed (11) comprising the first sulphur-removing catalyst and the second sulphur-removing catalyst under conditions whereby sulphur is removed from the process stream by the second sulphur-removing catalyst and said first sulphur-removing catalyst removes sulphur less efficiently from the stream at the operating temperature of the lag catalyst bed;

Abstract: Naphtha is selectively hydrodesulfurized in the presence of a sulfided, treated catalyst comprising at least a Group VIB metal catalytic component, to produce sulfur-reduced naphtha with reduced olefin loss due to saturation. The catalyst is treated with hydrogen, a selectively deactivating agent which deactivates its hydrogenation activity, and a protective agent which preserves its hydrodesulfurization activity during the treatment.

Abstract: A process for treating a carbonaceous material includes reacting the carbonaceous material and a process gas in supercritical water to at least one of hydrotreat and hydrocrack the carbonaceous material to form a treated carbonaceous material. The process is preferably carried out in a deep well reactor, but can be carried out in conventional surface-based reactors at a temperature of at least 705° F. and a pressure of at least 2500 psi.

Abstract: A process where the need to circulate hydrogen through the catalyst is eliminated. This is accomplished by mixing and/or flashing the hydrogen and the oil to be treated in the presence of a solvent or diluent in which the hydrogen solubility is “high” relative to the oil feed. The type and amount of diluent added, as well as the reactor conditions, can be set so that all of the hydrogen required in the hydroprocessing reactions is available in solution. The oil/diluent/hydrogen solution can then be fed to a plug flow reactor packed with catalyst where the oil and hydrogen react. No additional hydrogen is required, therefore, hydrogen recirculation is avoided and trickle bed operation of the reactor is avoided. Therefore, the large trickle bed reactors can be replaced by much smaller tubular reactor.

Abstract: A catalyst and process is disclosed to selectively upgrade a paraffinic feedstock to obtain an isoparaffin-rich product for blending into gasoline. The catalyst comprises a support of a sulfated oxide or hydroxide of a Group IVB (IUPAC 4) metal, a first component of at least one lanthanide element or yttrium component, which is preferably ytterbium, and at least one platinum-group metal component which is preferably platinum.

Abstract: A process for the treatment of light naphtha hydrocarbon streams is disclosed wherein the mercaptans contained therein are reacted with diolefins simultaneous with fractionation into a light stream and a heavy stream. The heavy stream is then simultaneously treated at high temperatures and low pressures and fractionated. The naphtha is then stripped of the hydrogen sulfide in a final stripper.

Abstract: A process for hydrotreating a hydrocarbon feedstock (1) involving the use of at least one hydrotreatment, particularly hydrodesulfurization, reactor (2) and a fractionation unit (3), which latter contains two distinct injection zones (4, 5) for the hydrocarbon feedstocks, a common zone (8) of vaporization of the light fractions and two distinct draw-off lines (6, 7) for the liquid bottoms; the hydrocarbon feedstock (1) being subjected to a preliminary treatment either in a first hydrodesulfurization reactor (20) the operating conditions of which (P, T, LHSV) may be different from those of the hydrotreatment reactor (2), or in a sweetening apparatus or else in a sulfur trap, the hydrocarbon feedstock being then injected into the first injection zone (4) of the fractionation unit (3), the liquid bottoms being removed through the draw-off line (6) of the injection zone (4) and passed into a hydrotreatment reactor (2), the effluents from said reactor (2) being injected into a second injection zone (5) of the frac