WO2013153318A1

WO2013153318A1 - Method for the hydrotreatment and dewaxing of a middle distillate feedstock using an izm-2 zeolite-based catalyst

Info

Publication number: WO2013153318A1
Application number: PCT/FR2013/050743
Authority: WO
Inventors: Emmanuelle Guillon; Christophe Bouchy; Magalie Roy-Auberger
Original assignee: IFP Energies Nouvelles
Priority date: 2012-04-11
Filing date: 2013-04-04
Publication date: 2013-10-17
Also published as: FR2989383B1; FR2989383A1

Abstract

The invention relates to a single-step method for the hydrotreatment and dewaxing of a middle distillate feedstock, using at least one catalyst comprising at least one hydro-dehydrogenating metal selected from the group formed by the metals from the VIB and VIII groups of the periodic table, either alone or in admixture, and a support comprising at least one IZM-2 zeolite and at least one binder. The method is performed at a temperature between 170 and 500° C, at a pressure between 0.1 and 25 MPa, at an hourly space velocity of between 0.05 and 50 h^-1 and in the presence of a total amount of hydrogen mixed with the feedstock such that the hydrogen/feedstock ratio is between 50 and 2000 normal litres of hydrogen per litre of feedstock.

Description

METHOD FOR HYDROTREATING AND DEPARAFFINING A MEDIUM DISTILLATE LOAD USING A ZEOLITE IZM-2 CATALYST

The present invention relates to a one-step process of hydrotreating and dewaxing a middle distillate filler.

Said process is carried out with at least one catalyst comprising at least one hydro-dehydrogenating metal selected from the group consisting of Group VIB metals and Group VIII of the Periodic Table, taken alone or as a mixture and a support comprising at least zeolite IZM-2 and at least one binder.

Prior art:

The treatment of the middle distillate-type petroleum fractions, that is to say of a feedstock comprising at least 95% by weight of boiling compounds at a boiling point of between 150 and 400 ° C. and preferably between 150 and 380 ° C. , said fillers having high levels of linear paraffins or little branched, is necessary in order to obtain good quality products which will then be used as diesel fuel or as kerosene or jet fuel.

This treatment consists on the one hand in eliminating linear or very poorly branched paraffins and with the best possible yields, on the other hand and concomitantly to eliminate heteroatoms such as sulfur so as to obtain a fuel specification.

Indeed, paraffins of high molecular weight which are linear or very weakly branched and which are present in middle distillates (gas oil and kerosene) lead to high pour points and thus to freezing phenomena for low temperature applications. . In order to decrease the pour point values, these linear paraffins which are not or very slightly connected must be completely or partially eliminated.

Selective cracking of the longer linear paraffinic chains which leads to the formation of lower molecular weight compounds, a portion of which can be removed by distillation, provides a solution for decreasing pour point values. Given their selectivity of form zeolites are among the most used catalysts for this type of process. The most used catalyst in the category of selective cracking dewaxing is zeolite ZSM-5, of structural type MFI, which has a three-dimensional porosity, with average pores (opening at 10 10MR oxygen atoms). However, cracking in such processes results in the formation of large amounts of lower molecular weight products, such as butane, propane, ethane, and methane, which greatly reduces the yield of desired products. Another solution to improve the cold resistance of a petroleum cut is to isomerize the linear paraffins present minimizing cracking as much as possible.

The shape selectivity of medium-pore monodimensional zeolites (10MR) such as zeolites ZSM-22, ZSM-23, NU-10, ZSM-48, ZBM-30 allows isomerization of the feeds by minimizing cracking reactions, which allows to increase the selectivity in desired products. However, these zeolitic catalysts are weakly active.

To overcome these drawbacks, the applicant has focused its research efforts on the development of catalysts both active and selective. The Applicant then surprisingly discovered that the use of a catalyst comprising at least one IZM-2 zeolite in a one-stage middle distillate hydrotreating and dewaxing process enables the point to be lowered. flow of said filler, while maintaining a good yield of desired products and decreasing the content of heteroelements such as sulfur of said filler.

Object of the invention

An object of the invention is to provide a method for hydrotreating and dewaxing in one step of a middle distillate filler, using at least one catalyst comprising at least one hydro-dehydrogenating metal selected from the group formed by metals group VIB and group VIII of the Periodic Table, taken alone or as a mixture and a carrier comprising at least one zeolite IZM-2 and at least one binder, said process operating at a temperature between 170 and 500 'Ό, at a pressure between 0.1 and 25 MPa, at a space velocity of between 0.05 and 50 h ^"1 and in the presence of a total amount of hydrogen mixed with the feed such that the hydrogen / feed ratio is between 50 and 2000 normal liters of hydrogen per liter of charge.

An advantage of the process according to the invention is to convert a medium distillate filler having a high pour point into a product having a lower pour point, and with the best possible yields.

Another advantage of the process according to the invention lies in the use of a catalyst based on IZM-2 zeolite making it possible to obtain an improvement in the pour point of said middle distillate filler while maintaining a high yield of sought after products.

Detailed description of the invention

The average distillate feedstock treated in the process according to the invention comprises at least 95% by weight of boiling compounds at a boiling point of between 150 and 400%, preferably between 150 and 380% and preferably between 200 and 380 ° C. The average distillate feedstock treated in the process according to the invention is advantageously a feedstock having a relatively high pour point whose value is to be reduced.

A typical middle distillate feed that can be processed in the process according to the invention has a pour point above -10 ° C. The process according to the present invention allows the production of products having pour points below 0 ° C and preferably below -10 ° C.

Preferably, said middle distillate filler treated in the process according to the invention is advantageously derived from direct distillation (or straight run according to English terminology).

Said filler may also advantageously be derived from a coking unit (coking according to the English terminology), a visbreaking unit (visbreaking according to the English terminology), a steam cracking unit (according to the English terminology). Anglo-Saxon terminology) and / or a catalytic cracking unit (Fluid Catalytic Cracking). Said charges can be taken alone or in a mixture.

The said middle distillate filler generally contains paraffins, olefins, naphthenes, aromatics and organic nitrogen, sulfur and oxygen compounds. Said middle distillate feed treated in accordance with the process of the invention contains a content of sulfur compounds advantageously of between 300 ppm and 5% by weight of sulfur and preferably of between 400 ppm and 5% by weight of sulfur.

Said feed contains a nitrogen compound content of between 40 ppm and 2% by weight, advantageously between 100 ppm and 2% by weight of nitrogen.

Said filler contains a paraffin content advantageously greater than 10% by weight and preferably greater than 20% by weight.

The catalyst according to the invention

According to the invention, the hydrotreatment and dewaxing process according to the invention uses at least one catalyst comprising at least one hydro-dehydrogenating metal selected from the group consisting of Group VIB and Group VIII metals. periodic classification, taken alone or as a mixture and a support comprising at least one zeolite IZM-2 and at least one binder.

The hydro / dehydrogenating function

Preferably, the elements of group VIII are chosen from the noble and non-noble metals of group VIII and preferably from iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium or platinum, alone or in combination, and preferred manner among cobalt, nickel, platinum and palladium, alone or as a mixture.

In the case where the elements of group VIII are chosen from the noble metals of group VIII, the elements of group VIII are advantageously chosen from platinum and palladium, taken alone or as a mixture. In this case, said elements are used in their reduced form.

In the case where the elements of group VIII are selected from non-noble metals of group VIII, the elements of group VIII are advantageously chosen from cobalt and nickel, taken alone or as a mixture. Preferably, the group VIB elements are chosen from tungsten and molybdenum, taken alone or as a mixture. In the case where the hydrogenating function comprises a group VIII element and a group VIB element, the following combinations of metals are preferred: nickel-molybdenum, cobalt-molybdenum, iron-molybdenum, iron-tungsten, nickel-tungsten, cobalt- tungsten, and very preferably: nickel-molybdenum, cobalt-molybdenum, nickel-tungsten. It is also possible to use combinations of three metals such as for example nickel-cobalt-molybdenum. When a combination of Group VI and Group VIII metals is used, the catalyst is then preferably used in a sulfurized form.

In the case where said catalyst comprises at least one noble metal of group VIII, the noble metal content of said catalyst is advantageously between 0.01 and 5% by weight, preferably between 0.1 and 4% by weight, and very preferred between 0.1 and 2% by weight relative to the total mass of said catalyst.

According to a preferred embodiment, said catalyst may also comprise tin in addition to said one or more noble metal (s), the tin content being preferably between 0.1 and 0.5% by weight relative to the total mass of catalyst.

In the case where the catalyst comprises at least one Group VIB metal in combination with at least one Group VIII non-noble metal, the Group VIB metal content is advantageously between 5 and 40% by weight of oxide relative to the total mass of said catalyst, preferably between 10 and 35% by weight of oxide and very preferably between 15 and 30% by weight of oxide and the non-noble metal content of group VIII is advantageously between 0, 5 and 10% by weight of oxide relative to the total mass of said catalyst, preferably between 1 and 8% by weight of oxide and very preferably between 1, 5 and 6% by weight of oxide.

IZM-2 zeolite

According to the invention, said catalyst comprises a support comprising at least one zeolite IZM-2 and at least one binder.

Preferably, said support comprises from 2 to 80% by weight, and preferably from 5 to 50% by weight of zeolite IZM-2 relative to the total mass of said support. The IZM-2 zeolite is a crystallized microporous solid having a crystalline structure described in the patent application FR 2 918 050. The process for preparing the zeolite IZM-2 is also described in said application.

Said IZM-2 solid has a chemical composition expressed on an anhydrous basis, in terms of moles of oxides, defined by the following general formula: X0 ₂ : aY ₂ 0 ₃ : bM ₂ / nO, wherein X represents at least one tetravalent element, Y represents at least one trivalent element and M is at least one alkali metal and / or alkaline earth metal of valence n.

X is preferably selected from silicon, germanium, titanium and the mixture of at least two of these tetravalent elements, very preferably X is silicon and Y is preferably selected from aluminum, boron, iron, indium and gallium, very preferably Y is aluminum. M is preferably selected from lithium, sodium, potassium, calcium, magnesium and the mixture of at least two of these metals and very preferably M is sodium. Preferably, X represents silicon, the crystallized solid IZM-2 according to the invention is then an entirely silicic solid when element Y is absent from the composition of said solid IZM-2. It is also advantageous to use as element X a mixture of several elements _T, in particular a mixture of silicon with another element X chosen from among germanium and titanium, preferably germanium. Thus, when the silicon is present in a mixture with another element X, the crystallized solid IZM-2 according to the invention is then a crystallized metallosilicate having an X-ray diffraction pattern identical to that described in Table 1 of the FR 2 patent. 918 050 when in its calcined form. Even more preferably and in the presence of an element Y, X being silicon and Y being aluminum: the crystallized solid IZM-2 according to the invention is then an aluminosilicate.

Preferably, IZM-2 zeolite is in aluminosilicate form.

Preferably, the molar ratio of the number of silicon atoms to the number of aluminum atoms Si / Al is less than 200, preferably less than 150, very preferably less than 120.

The zeolite IZM-2 used in the composition of the support of the catalyst according to the invention is advantageously exchanged by at least one treatment with a solution of at least one ammonium salt so as to obtain the ammonium form of the zeolite IZM-2 which once calcined leads to the acid form (H ⁺ ) of said zeolite IZM-2. This exchange step can be carried out at any stage of the catalyst preparation, that is to say after the step of preparation of the zeolite IZM-2, after the step of shaping the zeolite IZM- 2 by a porous mineral binder, or after the step of introducing the hydro-dehydrogenating metal. Said zeolite IZM-2 used in the composition of the catalyst support used in the process according to the invention is advantageously at least partly, preferably almost completely, in acid form, that is to say in H ⁺ form. The binder

According to the invention, the catalyst support used in the process according to the invention contains a binder. Said binder can advantageously be amorphous or crystallized. Preferably, said binder is advantageously chosen from the group formed by alumina, silica, silica-alumina, clays, titanium oxide, boron oxide and zirconia, taken alone or as a mixture. It is also possible to choose aluminates. Preferably, said binder of the support is alumina. Preferably, said support binder is alumina in all its forms known to those skilled in the art, such as, for example, alpha, gamma, eta, delta type aluminas. Said aluminas differ in their specific surface area and their pore volume.

The support

Preferably, said support comprises from 20 to 98% by weight of binder, and very preferably from 50 to 95% by weight relative to the total mass of said support. Said support is preferably in the form of beads, grains or extrusions.

The catalyst according to the invention and preferably the support of the catalyst according to the invention may also advantageously contain at least one other zeolite, and preferably a zeolite chosen from zeolites of structure FER, BEA, TON, MRE, FAU, AEI, AFO, and even more preferably among zeolites ferrierite, beta, ZSM-48, ZSM-22, ZBM-30, Y, USY, NU-86, SAPO-11 and SAPO-18.

Formatting of the IZM2 / binder support

The catalyst support used in the process according to the invention can advantageously be prepared according to all methods well known to those skilled in the art.

According to a preferred method of preparation, said crystallized zeolite IZM-2 may advantageously be introduced during the dissolution or suspension of the binder advantageously used according to the invention. Said crystallized zeolite IZM-2 may be, without limitation, for example in the form of powder, ground powder, suspension, suspension having undergone deagglomeration treatment. Thus, for example, said crystallized zeolite may advantageously be slurried acid-free or not at a concentration adjusted to the final content of IZM-2 solid referred to in the catalyst used according to the present invention. This suspension, commonly known as a slurry, is then mixed with the alumina compounds.

The catalyst support used in the process according to the invention may advantageously be shaped by any technique known to those skilled in the art. The shaping can advantageously be carried out for example by extrusion, by pelletization, by the method of drop coagulation ("oil-drop"), by rotating plate granulation or by any other method well known to those skilled in the art. . The shaping may advantageously also be carried out in the presence of the various constituents of the catalyst and extrusion of the obtained mineral paste, by pelletizing, shaped into beads at the rotating bezel or drum, drop coagulation, "oil drop" , "oil-up", or any other known method of agglomeration of a powder containing alumina and optionally other ingredients selected from those mentioned above. Furthermore, the supports used in the process according to the present invention may advantageously have been treated as is well known to those skilled in the art by additives to facilitate the shaping and / or improve the final mechanical properties. supports. By way of example of additives, there may be mentioned in particular cellulose, carboxymethylcellulose, carboxyethylcellulose, tall oil, xanthan gums, surfactants, flocculating agents such as polyacrylamides, carbon black, starches, stearic acid, polyacrylic alcohol, polyvinyl alcohol, biopolymers, glucose, polyethylene glycols, etc.

Water may be advantageously added or removed to adjust the viscosity of the paste to be extruded.

This step can advantageously be carried out at any stage of the kneading step.

In order to adjust the solid content of the paste to be extruded to make it extrudable, it is also advantageous to add a predominantly solid compound and preferably an oxide or a hydrate. A hydrate is preferably used and even more preferably an aluminum hydrate. The loss on ignition of this hydrate is advantageously greater than 15%.

Extrusion can advantageously be performed by any conventional tool, commercially available. The paste resulting from the mixing is advantageously extruded through a die, for example by means of a piston or a single screw or twin extrusion screw. This extrusion step may advantageously be carried out by any method known to those skilled in the art.

Thermal treatment of IZM-2 / binder

After shaping, the catalyst support used in the process according to the present invention is then advantageously subjected to a drying step.

Said drying step is advantageously carried out by any technique known to those skilled in the art.

Preferably, the drying is carried out under air flow. Said drying can also be advantageously carried out under a stream of any oxidizing, reducing or inert gas. Preferably, the drying is advantageously carried out between 50 and Ι δΟ 'Ό, preferably between 60 and 150 ° C and very preferably between 80 and 130 ° C.

Said support, optionally dried, then preferably undergoes a calcination step. Said calcination step is advantageously carried out in the presence of molecular oxygen, for example by conducting a sweep of air, at a temperature advantageously greater than 200 ° C. and less than or equal to 1100 ° C. Said calcination step may advantageously be carried out in a crossed bed, in a licked bed or in a static atmosphere. For example, the furnace used may be a rotating rotary kiln or a vertical kiln with radial traversed layers. Preferably, said calcination step is carried out for more than one hour at 200 ° C and less than 1 hour at 1100 ° C. The calcination can advantageously be carried out in the presence of steam and / or in the presence of an acidic or basic vapor. For example, the calcination can be carried out under partial pressure of ammonia.

Post-calcination treatments may optionally be carried out so as to improve the properties of the support, for example texturally.

Post-synthesis treatments of IZM-2 / binder support

The IZM-2 support / catalyst binder used in the process according to the present invention can thus optionally be subjected to a hydrothermal treatment in a confined atmosphere. Hydrothermal treatment in a confined atmosphere means treatment by autoclaving in the presence of water at a temperature above room temperature.

During this hydrothermal treatment, the support can advantageously be treated. Thus, the support can advantageously be impregnated, prior to its autoclaving, the autoclaving being done either in the vapor phase or in the liquid phase, this vapor or liquid phase of the autoclave possibly being acidic or not. This impregnation, prior to autoclaving, may advantageously be acidic or not. This impregnation, prior to autoclaving may advantageously be carried out dry or by immersion of the support in an acidic aqueous solution. Dry impregnation means contacting the support with a solution volume less than or equal to the total pore volume of the support. Preferably, the impregnation is carried out dry.

The autoclave is preferably a rotary basket autoclave such as that defined in patent application EP-A-0 387 109.

The temperature during the autoclaving may be between 100 and 250 ° C for a period of time between 30 minutes and 3 hours.

Deposition of the hydro-dehydrogenating function

The hydro-dehydrogenating function may advantageously be introduced at any stage of the preparation, very preferably after shaping of said IZM-2 / binder support. The shaping is advantageously followed by calcination, the hydro-dehydrogenating function can also advantageously be introduced before or after this calcination. The preparation generally ends with calcination at a temperature of 250 to 600 ° C. Another of the preferred methods according to the present invention advantageously consists in shaping the IZM-2 / binder support after kneading thereof, then passing the dough thus obtained through a die to form extrudates. The hydro-dehydrogenating function may advantageously then be introduced in part only or in full, at the time of mixing. It can also advantageously be introduced by one or more ion exchange operations on the calcined support.

In a preferred manner, the support is impregnated with an aqueous solution. The impregnation of the support is preferably carried out by the "dry" impregnation method well known to those skilled in the art. The impregnation may advantageously be carried out in a single step by a solution containing all the constituent elements of the final catalyst. The hydro-dehydrogenating function may advantageously be introduced by one or more impregnation operations of the shaped and calcined support, with a solution containing at least one precursor of at least one oxide of at least one metal chosen from the group formed. by the Group VIII metals and the Group VIB metals, the precursor (s) of at least one oxide of at least one Group VIII metal being preferably introduced after those of Group VIB or same time as the latter, if the catalyst contains at least one Group VIB metal and at least one Group VIII metal.

In the case where the catalyst advantageously contains at least one element of group VIB, for example molybdenum, it is for example possible to impregnate the catalyst with a solution containing at least one element of group VIB, to dry, to calcine. The impregnation of molybdenum may advantageously be facilitated by the addition of phosphoric acid in the ammonium paramolybdate solutions, which also makes it possible to introduce the phosphorus so as to promote the catalytic activity.

The following elements: boron and / or silicon and / or phosphorus can be introduced into the catalyst at any level of the preparation and according to any technique known to those skilled in the art.

A preferred method according to the invention consists in depositing the selected promoter element or elements, for example the boron-silicon pair, on the IZM-2 support formed with the calcined or non-calcined binder, preferably calcined. For this purpose, an aqueous solution of at least one boron salt, such as ammonium biborate or ammonium pentaborate, is prepared in an alkaline medium and in the presence of hydrogen peroxide, and a so-called dry impregnation is carried out in which the pore volume of the precursor is filled with the solution containing, for example, boron. In the case where, for example, silicon is also deposited, for example a solution of a silicon-type silicon compound or a silicone oil emulsion is used. The element (s) promoter (s) chosen (s) in the group formed by silicon, boron and phosphorus can advantageously be introduced by one or more impregnation operations with excess solution on the calcined precursor.

The boron source may advantageously be boric acid, preferably orthoboric acid H ₃ B0 ₃ , ammonium biborate or pentaborate, boron oxide, boric esters. Boron may for example be introduced in the form of a mixture of boric acid, hydrogen peroxide and a basic organic compound containing nitrogen such as ammonia, primary and secondary amines, cyclic amines, compounds of the family of pyridine and quinolines and compounds of the pyrrole family. Boron may be introduced for example by a boric acid solution in a water / alcohol mixture. The preferred phosphorus source is orthophosphoric acid H ₃ PO ₄ , but its salts and esters such as ammonium phosphates are also suitable. The phosphorus may for example be introduced in the form of a mixture of phosphoric acid and a basic organic compound containing nitrogen such as ammonia, primary and secondary amines, cyclic amines, compounds of the family of pyridine and quinolines and compounds of the pyrrole family.

Many sources of silicon can advantageously be employed. Thus, it is possible to use ethyl orthosilicate Si (OEt) ₄ , siloxanes, polysiloxanes, silicones, silicone emulsions, halide silicates, such as ammonium fluorosilicate (NH ₄ ) ₂ SiF ₆ or sodium fluorosilicate Na ₂ SiF ₆ . Silicomolybdic acid and its salts, silicotungstic acid and its salts can also be advantageously employed. Silicon may advantageously be added for example by impregnation of ethyl silicate in solution in a water / alcohol mixture. Silicon can be added, for example, by impregnating a silicon-type silicon compound or silicic acid suspended in water.

The noble metals of group VIII of the catalyst of the present invention may advantageously be present in whole or in part in metallic and / or oxide form.

The noble element sources of group VIII which can advantageously be used are well known to those skilled in the art. For the noble metals halides are used, for example chlorides, nitrates, acids such as chloroplatinic acid, hydroxides, oxychlorides such as ruthenium ammoniacal oxychloride. It is also advantageous to use cationic complexes such as ammonium salts when it is desired to deposit the platinum on the IZM-2 solid by cation exchange.

The catalysts thus obtained are shaped in the form of grains of different shapes and sizes. They are generally used in the form of cylindrical or multi-lobed extrusions such as bilobed, trilobed, straight-lobed or twisted, but can possibly be manufactured and used in the form of crushed powders, tablets, rings, balls, wheels. Other techniques than extrusion, such as pelletizing or coating, can advantageously be used.

Preferably, the catalysts used in the process according to the invention are in the form of spheres or extrusions. It is however advantageous that the catalyst is in the form of extrudates with a diameter of between 0.5 and 5 mm and more particularly between 0.7 and 2.5 mm. The shapes are cylindrical (which can be hollow or not), cylindrical twisted, multilobed (2, 3, 4 or 5 lobes for example), rings. The cylindrical shape is preferably used in a preferred manner, but any other form may advantageously be used.

In the case where the catalyst used in the process according to the invention comprises at least one noble metal, the noble metal contained in said catalyst must be reduced. The reduction of the metal is advantageously carried out by treatment in hydrogen at a temperature of between 150 ° C. and 650 ° C. and a total pressure of between 0.1 and 25 MPa. For example, a reduction consists of a stage at 150 ° C. for two hours and then a rise in temperature up to 450 ° C. at a rate of 1 ° C./min and then a two-hour stage at 450 ° C. throughout this reduction step, the hydrogen flow rate is 1000 normal m ³ hydrogen per m ³ catalyst and the total pressure kept constant at 0.1 MPa. Any ex-situ reduction method can advantageously be considered.

In the case where the catalyst used in the process according to the invention comprises at least one Group VIB metal in combination with at least one Group VIII non-noble metal, the metals are preferably used in their sulfurized form. The sulphidation of the catalyst can be carried out in situ or ex situ by any method known to those skilled in the art.

The catalyst used in the process according to the invention can advantageously be used in beds combined with one or more hydrotreatment catalysts.

The hydrotreatment catalysts that can be used are conventional hydrotreatment catalysts known to those skilled in the art. In particular, said catalysts comprise at least one Group VIII metal, at least one Group VIB metal and at least one support formed of at least one oxide. Preferably, the active phase of the hydrotreatment catalysts consists of a "mixed" sulphide phase constituted by sheets of molybdenum disulphide (tungsten, respectively) decorated with promoter atoms (cobalt or nickel, most often) at the periphery. . Preferably the support is alumina. Operating conditions

According to the invention, said process operates at a temperature between 170 and 500 ° C, preferably between 250 and 440 ° C, at a pressure of between 0.1 and 25 MPa,

Preferably between 1 and 20 MPa, at a space velocity of between 0.05 and 50 h preferably between 0.1 and 20 h ^-1 and even more preferably between 0.1 and 10 h ^-1 and in the presence of a total amount of hydrogen mixed with the feed such that the hydrogen / feed ratio is between 50 and 2000 normal liters of hydrogen per liter of charge and preferably between 100 and 1500 normal liters of hydrogen per liter of charge.

The one-step hydrotreating and dewaxing process according to the present invention operating under the above conditions makes it possible to convert a medium distillate filler having a high pour point into a product having a lower pour point, and this with the best possible yields in desired products.

In particular, the process according to the present invention allows the production of products having pour points below 0 ° C and preferably below -10 ° C. The examples which follow illustrate the invention without, however, limiting its scope.

Example 1 Preparation of the catalyst C1 according to the invention

Catalyst C1 contains an IZM-2 zeolite. This catalyst is obtained according to the procedure described below.

The IZM-2 zeolite was synthesized according to the teaching of the patent application FR 2 918 050.

The synthetic IZM-2 zeolite is subjected to calcination at 550 ° C. under a stream of dry air for 12 hours. The zeolite IZM-2, after cation exchange, is in acid form and has an Si / Al atomic ratio of 70. The zeolite is kneaded with an alumina gel (ultrafine tabular boehmite). The kneaded paste is then extruded through a die of diameter 1, 4 mm. The extrudates thus obtained are calcined at 500 ° C. for 2 hours under dry air. The amounts of zeolite IZM-2 and alumina gel are adjusted to obtain 50% by weight of zeolite IZM-2 in the carrier.

The support in the form of extrudates, obtained above, is impregnated dry with an impregnating solution prepared by hot dissolving molybdenum oxide (MoO ₃ ), nickel hydroxide (Ni (OH) ₂ ). in a solution of phosphoric acid (H ₃ PO ₄ ) in aqueous solution. After dry impregnation, the extrudates are allowed to mature in a saturated water atmosphere for 12 hours, then they are dried overnight at 90 ° C. and calcined under dry air at 450 ° C. for 2 hours. The amounts of molybdenum oxide, nickel hydroxide and phosphoric acid are adjusted to obtain the desired levels of molybdenum, nickel and phosphorus on the catalyst. The molybdenum, nickel and phosphorus contents of the catalyst, expressed as oxides, are as follows: 15.9% by weight MoO ₃ ; 2.9% NiO and 2.8% P ₂ O ₅ .

EXAMPLE 2 Use of Catalyst C1 (in Accordance with the Invention) in a Hydrotreatment and Dewaxing Process for Diesel Fuel Catalyst C1 is used for the hydrotreatment and dewaxing of an atmospheric distillation gas oil, the main characteristics of which are given in the table below. The hydrotreatment and the dewaxing are carried out in a fixed-bed reactor with a lost hydrogen (no recycling of hydrogen).

Characteristics of the atmospheric distillation azole

The catalyst is sulfided in situ in the reactor prior to the catalytic test. This sulphurization is carried out in the presence of hydrogen with the atmospheric distillation gas oil additive of 2% by weight of DMDS dimethyldisulfide evolutions under the following conditions:

a total pressure of 5 MPa,

- a hourly volume velocity (VVH) with respect to the 2 h ^-1 adducted diesel

a hydrogen / gas oil ratio additive at the reactor inlet of 400 normal liters of hydrogen per liter of additized diesel fuel.

The heat treatment performed during this sulphurization step is as follows. After one hour at 100 ° C., the temperature is increased with a ramp of 25 ° C. / hour up to 220 ° C. and then with a ramp of 12 ° C./hour until reaching a plateau of 350 ° C., maintained for 12 hours. .

The non-additive atmospheric distillation gas oil is then injected, then the hourly volume velocity, the total pressure and the temperature are adjusted to the test conditions (ramp of temperature rise of 2 ^< C per minute is used).

The conditions for hydrotreating and de-scaling are as follows:

a total pressure of 7 MPa,

a hourly volume velocity (VVH) relative to the diesel fuel of 1 h ^-1 ,

a hydrogen / diesel output from the reactor of 400 normal liters of hydrogen per liter of diesel fuel.

a temperature of 360 ° C. The characteristics of the effluent obtained are given in the table below. The yield of 165 ° C ⁺ cut can be calculated from the simulated distillation of the effluent and is equal to 92% by weight. It is thus found that the hydrotreatment and dewaxing of the atmospheric distillation gas oil on the catalyst C1 according to the invention makes it possible both to reduce the content of heteroelement sulfur and nitrogen and also to reduce the pour point of the diesel fuel while maintaining a high yield of the 165 ^q C ⁺ cut.

Characteristics of the effluent

Claims

1. A one-step process for hydrotreating and dewaxing a middle distillate feed comprising at least 95 wt.% Of boiling compounds at a boiling point of 150 to 400 ° C employing at least one catalyst comprising at least one hydro-dehydrogenating metal selected from the group consisting of Group VIB metals and Group VIII of the Periodic Table, taken alone or as a mixture and a carrier comprising at least one IZM-2 zeolite and at least one binder, said process operating at a temperature between 170 and 500 ° C, at a pressure of between 0.1 and 25 MPa, at a space velocity of between 0.05 and 50 h ^"1 and in the presence of a total amount of hydrogen mixed with the charge such that the hydrogen / charge ratio is between 50 and 2000 normal liters per liter of charge.

2. Method according to one of claims 1 wherein said charge is selected from the charges from the direct distillation, the charges from a coker unit, a visbreaking unit, a steam cracking unit and a catalytic cracking unit, alone or as a mixture.

3. Method according to one of claims 1 to 2 wherein said filler contains a content of sulfur compounds of 300 ppm and 5% by weight of sulfur.

4. Method according to one of claims 1 to 3 wherein said feed contains a nitrogen compound content of 100 ppm and 2% by weight of nitrogen.

5. Method according to one of claims 1 to 4 wherein the group VIII elements are selected from cobalt, nickel, platinum and palladium, alone or in mixture.

6. The method of claim 5 wherein the noble metal content of said catalyst is between 0.01 and 5% by weight relative to the total mass of said catalyst.

7. Method according to one of claims 1 to 6 wherein the group VIB elements are selected from tungsten and molybdenum, alone or in mixture.

8. Process according to one of claims 1 to 5 and 7 wherein the group VIB metal content is between 5 and 40% by weight of oxide relative to the total mass of said catalyst, and the content of non-metal The noble group VIII is between 0.5 and 10% by weight of oxide relative to the total mass of said catalyst.

9. Method according to one of claims 1 to 8 wherein the support of said catalyst comprises from 2 to 80% by weight of zeolite IZM-2 relative to the total mass of said support.

10. Method according to one of claims 1 to 9 wherein said binder is selected from the group consisting of alumina, silica, silica-alumina, clays, titanium oxide, boron oxide and zirconia, taken alone or as a mixture.

1 1. The method of claim 10 wherein the support of said catalyst comprises from 20 to 98% by weight of binder based on the total weight of said carrier.

12. Method according to one of claims 1 to 1 1 wherein said process operates at a temperature between 250 and 430 'Ό, at a pressure between 1 and 20 MPa, at a space velocity of between 0> ^{1 and "Ό} ⁿ and in the presence of a total amount of hydrogen mixed with the feedstock such that the hydrogen / feedstock ratio is between 100 and 1500 liters of hydrogen per liter of feed.