Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G45/00—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds
  • C10G45/58—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to change the structural skeleton of some of the hydrocarbon content without cracking the other hydrocarbons present, e.g. lowering pour point; Selective hydrocracking of normal paraffins
  • C10G45/60—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to change the structural skeleton of some of the hydrocarbon content without cracking the other hydrocarbons present, e.g. lowering pour point; Selective hydrocracking of normal paraffins characterised by the catalyst used
  • C10G45/62—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to change the structural skeleton of some of the hydrocarbon content without cracking the other hydrocarbons present, e.g. lowering pour point; Selective hydrocracking of normal paraffins characterised by the catalyst used containing platinum group metals or compounds thereof
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G2400/00—Products obtained by processes covered by groups C10G9/00 - C10G69/14
  • C10G2400/10—Lubricating oil

Definitions

• the present invention relates to a method for improving the pour point of hydrocarbon charges originating from the Fischer-Tropsch process, in particular for converting, with good efficiency, charges having high pour points into at least one section having a point low flow and a high viscosity index for oil bases, by passing over a catalytic hydrodewaxing catalyst comprising at least one zeolite (molecular sieve) ZBM-30 synthesized in the presence of a particular structuring agent such as triethylenetetramine, at least one porous mineral matrix, at least one hydro-dehydrogenating element, preferably chosen from elements of group VI B and group VIII of the periodic table.
• a catalytic hydrodewaxing catalyst comprising at least one zeolite (molecular sieve) ZBM-30 synthesized in the presence of a particular structuring agent such as triethylenetetramine, at least one porous mineral matrix, at least one hydro-dehydrogenating element, preferably chosen from elements of group VI B and group VIII of the periodic table.
• This operation can be carried out by extraction with solvents such as propane or methyl ethyl ketone, this is called propane or methyl ethyl ketone dewaxing (MEK).
• solvents such as propane or methyl ethyl ketone
• MEK propane or methyl ethyl ketone dewaxing
• zeolites are among the most used catalysts.
• the idea which prevails in their use is that there are zeolitic structures whose pore openings are such that they allow the entry into their microporosity of long linear paraffins or very little branched but exclude branched paraffins, napthenes and aromatics. This phenomenon thus leads to a selective cracking of linear or very poorly branched paraffins.
• Zeolite catalysts having intermediate pore sizes such as ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35 and ZSM-38 have been described for their use in these processes especially in US patents 3,894,938; US 4,176,050; US 4,181,598; US 4,222,855; US 4,229,282 and US 4,247,388.
• the applicant has focused its research efforts on the development of a process for improving the pour point of hydrocarbon feedstocks resulting from the Fischer-Tropsch process using catalysts comprising at least one ZBM-30 zeolite, at least one hydro-dehydrogenating element, preferably chosen from the elements of group VI B and group VIII of the periodic table.
• the Applicant then surprisingly discovered that the use of a catalyst comprising at least one ZBM-30 zeolite synthesized with a particular structuring agent such as triethylene tetramine makes it possible to lower the pour point of the charge while obtaining a high viscosity index (VI) and maintaining a good yield of desired products.
• a particular structuring agent such as triethylene tetramine
• the catalyst prepared with the zeolite ZBM-30 synthesized in the presence of the structuring agent triethylene tetramine exhibits a higher activity and a selectivity in dewaxing (improvement of the pour point) than the solids based on ZBM-30 synthesized via other structuring agents and than the catalytic formulas based on zeolites known from the prior art.
• the present invention provides a catalytic process for the reduction of the pour point based on such catalysts.
• the invention relates to a process for improving the pour point of a paraffinic filler produced by Fischer-Tropsch synthesis, in which the filler to be treated is brought into contact with a catalyst comprising at least one ZBM- zeolite 30 synthesized with a particular structuring agent such as triethylenetetramine, at least one hydro-dehydrogenating element, preferably chosen from the elements of group VIB and group VIII of the periodic table, at least one porous mineral matrix.
• a catalyst comprising at least one ZBM- zeolite 30 synthesized with a particular structuring agent such as triethylenetetramine, at least one hydro-dehydrogenating element, preferably chosen from the elements of group VIB and group VIII of the periodic table, at least one porous mineral matrix.
• This dewaxing process is carried out at a temperature between 200 and 450 ° C, a pressure between 0J and 25 MPa and an hourly volume speed between 0.05 and 30 h "1 , in the presence of hydrogen at a rate of 50 to 2000 normal liters of hydrogen per liter of charge (Nl / I).
• said catalyst exhibits an activity and a selectivity in dewaxing (improvement in the flow point of the charges resulting from the Fischer-Tropsch process) greater than the catalytic formulas based on zeolites (molecular sieve) known in the prior art.
• this process makes it possible to convert a charge having a high pour point into a product having a lower pour point and makes it possible to obtain oil bases having good cold properties and a high viscosity index and gas oils of good quality.
• the fillers which can be treated according to the process of the invention are advantageously fractions having relatively high pour points whose value it is desired to reduce.
• Typical fillers which can be advantageously treated according to the invention generally have a pour point above 0 ° C.
• the products resulting from the treatment according to the process have pour points of less than 0 ° C and preferably less than about -10 ° C.
• the process according to the invention allows, in particular, the production of products with a low pour point with good yields, and with a high viscosity index in the case of the heaviest fractions which are processed for the purpose of producing oil bases.
• the process according to the invention uses a catalyst which comprises at least one ZBM-30 zeolite synthesized with a particular structuring agent such as triethylene tetramine, at least one hydro-dehydrogenating element, preferably chosen from the elements of group VIB and of group VIII of the periodic table and at least one porous mineral matrix.
• a particular structuring agent such as triethylene tetramine
• a hydro-dehydrogenating element preferably chosen from the elements of group VIB and of group VIII of the periodic table and at least one porous mineral matrix.
• the ZB -30 zeolite is synthesized according to the methods described in patent EP-A-46504 according to the procedure using the structuring agent triethylenetetramine.
• the overall Si / Ai ratio of the zeolites entering into the composition of the catalysts according to the invention as well as the chemical composition of the samples are determined by X-ray fluorescence and atomic absorption.
• the Si / Ai ratios of the zeolites described above are those obtained on synthesis according to the procedures described in the various documents cited or obtained after post-synthesis dealumination treatments well known to those skilled in the art, such as that and in a non-exhaustive manner hydrothermal treatments followed or not by acid attacks or even direct acid attacks by solutions of mineral or organic acids.
• the zeolites used in the composition of the catalysts of the process according to the invention can be calcined and exchanged by at least one treatment with a solution of at least one ammonium salt so as to obtain the ammonium form of the zeolites which once calcined leads to the hydrogen form of said zeolites.
• the zeolites used in the composition of the catalyst of the process according to the invention are at least partly, preferably practically completely, in acid form, that is to say in hydrogen form (H + ).
• the Na / T atomic ratio is generally less than 10% and preferably less than 5% and even more preferably less than 1%.
• the catalyst contains at least one hydro-dehydrogenating element, preferably chosen from the elements of group VIB and group VIII (that is to say metal or compound) of the periodic table and at least one matrix porous mineral.
• the element is at least one metal from group VIII, preferably when it is at least one noble metal and advantageously a noble metal chosen from the group formed by platinum and palladium, it can be introduced onto zeolites, for example by dry impregnation, by ion exchange or any other method known to those skilled in the art, or it can be introduced onto the matrix.
• the zeolite previously described prior to its shaping the zeolite previously described is subjected to the deposition of at least one metal from group VIII, preferably chosen from the group formed by platinum and palladium.
• the zeolite is then shaped by any technique known to those skilled in the art. It can in particular be mixed with a matrix, generally amorphous, for example with a wet powder of alumina gel. The mixture is then shaped, for example by extrusion through a die.
• the shaping can be carried out with matrices other than alumina, such as for example magnesia, amorphous silica-aluminas, natural clays (kaolin, bentonite, sepiolite, attapulgite), silica, oxide of titanium, boron oxide, zirconia, aluminum phosphates, titanium phosphates, zirconium phosphates, carbon and their mixtures.
• matrices containing alumina in all its forms known to those skilled in the art, and even more preferably aluminas, for example gamma alumina.
• Other techniques than extrusion such as pelletizing or coating, can be used.
• mixtures of alumina and silica mixtures of alumina and silica-alumina.
• the catalysts obtained are shaped in the form of grains of different shapes and dimensions. They are generally used in the form of cylindrical or multi-lobed extrudates such as two-lobed, three-lobed, multi-lobed in straight or twisted shape, but can optionally be produced and used in the form of crushed powders, tablets, rings, balls , wheels.
• the product obtained is subjected to a drying step and then to a calcination step.
• the hydrogenating metal belongs to group VIII, and preferably is platinum and / or palladium
• it can also and advantageously be deposited on the support after the shaping of the zeolite free of metals, by any known process skilled in the art and allowing the deposition of the metal on the molecular sieve.
• the support is obtained in a manner analogous to that described above.
• support will denote the zeolite (free from metals), plus the matrix after shaping, drying and calcination, for example as previously obtained.
• the cation exchange technique can be used with 1 competition where the competitor is preferably ammonium nitrate, the competition ratio being at least equal to approximately 20 and advantageously from approximately 30 to 200.
• the competitor is preferably ammonium nitrate
• a tetramine complex of platinum or a tetramine complex of palladium is usually used: the latter will then be deposited almost entirely on the zeolite.
• This cation exchange technique can also be used to deposit the metal directly on the molecular sieve powder, before possible mixing with a matrix.
• the deposition of the metal (or metals) of group VIII is generally followed by calcination in air or oxygen, usually between 300 and 600 ° C. for 0.5 to 10 hours, preferably between 350 ° C and 550 ° C for 1 to 4 hours. A reduction can then be carried out under hydrogen, generally at a temperature between 300 and 600 ° C for 1 to 10 hours, preferably one will operate between 350 ° and 550 ° C for 2 to 5 hours.
• Platinum and / or palladium can also be deposited no longer directly on the zeolite, but on the matrix (for example the aluminum binder) of the support, before or after the shaping step, by implementing an anion exchange with hexachloroplatinic acid, hexachloropalladic acid and / or palladium chloride in the presence of a competing agent, for example hydrochloric acid.
• a competing agent for example hydrochloric acid.
• the catalyst is as previously subjected to calcination and then reduced under hydrogen as indicated above.
• the support for the catalytic dewaxing catalyst according to the present invention generally contains the following contents of matrix and zeolites:
• the content of noble metal (s) thus optionally introduced, expressed in% by weight relative to the total mass of the catalyst, is generally less than 5%, preferably less than 3%, even more preferably less than 2% and generally less than 1% by weight.
• the catalyst comprises a hydrogenating metal from group VIII, preferably a noble metal and advantageously platinum and / or palladium
• the catalyst is generally reduced in the reactor in the presence of hydrogen and under conditions well known to the skilled in the art.
• the elements of group VIB and of group VIII optionally introduced into the catalyst according to the invention may be present in whole or in part in the metallic form and / or oxide and / or sulfide.
• the elements of group VIB molybdenum and tungsten are preferred.
• the sources of the VIB group element which can be used are well known to those skilled in the art.
• oxides and hydroxides, molybdic and tungstic acids and their salts in particular ammonium salts such as ammonium molybdate, ammonium heptamolybdate, ammonium tungstate, phosphomolybdic acid, phosphotungstic acid and their salts.
• ammonium oxides and salts such as ammonium molybdate, ammonium heptamolybdate and ammonium tungstate
• the dewaxing catalyst according to the present invention may contain a non-noble metal from group VIII and preferably cobalt and nickel.
• a non-noble metal from group VIII preferably cobalt and nickel.
• associations of elements from groups VI and VIII which are non-noble: nickel-molybdenum, cobalt-molybdenum, iron-molybdenum, iron-tungsten, nickel-tungsten, cobalt-tungsten
• the preferred associations are: nickel -molybdenum, nickel-tungsten. It is also possible to use combinations of three metals, for example nickel-cobalt-molybdenum.
• Group VIII elements which can be used are well known to those skilled in the art.
• nitrates, sulfates, phosphates, halides for example, chlorides, bromides and fluorides, carboxylates for example acetates and carbonates will be used.
• composition of the support consisting of at least one matrix and of the zeolites described in the invention is the same as that described above, and
• the content by weight of at least one element chosen from elements of group VIB and of group VIII which are not noble is between 0J and 60%, preferably between 1 and 50% and even more preferably between 2 and 40%.
• the wet solid is left to stand under a humid atmosphere at a temperature between 10 and 80 ° C., then the wet solid obtained is dried at a temperature between 60 and 150 ° C., and finally we calcines the solid obtained at a temperature between 150 and 800 ° C, generally between 250 and 600 ° C.
• the catalysts of the process of the present invention can optionally be subjected to a sulphurization treatment making it possible to transform, at least in part, the metallic species into sulphide before they are brought into contact with the charge to be treated.
• This activation treatment by sulfurization is well known to those skilled in the art and can be carried out by any method already described in the literature.
• a conventional sulfurization method well known to those skilled in the art consists of heating in the presence or under flow of a hydrogen / hydrogen sulfide mixture or even under pure hydrogen sulfide, at a temperature comprised between 150 and 800 ° C, preferably between 250 and 600 ° C, generally in a crossed-bed reaction zone.
• hydrocarbon feedstocks treated according to the process of the invention are feedstocks produced by Fischer-Tropsch synthesis and advantageously fractions having relatively high pour points whose value it is desired to reduce.
• the synthesis gas (CO + H 2 ) is catalytically transformed into oxygenated products and essentially linear hydrocarbons in gaseous, liquid or solid form.
• oxygenated products are generally free from heteroatomic impurities such as, for example, sulfur, nitrogen or metals. They also contain practically little or no aromatics, naphthenes and more generally rings, in particular in the case of cobalt catalysts.
• they can have a non-negligible content of oxygenated products which, expressed by weight of oxygen, is generally less than 5% by weight approximately and also a content of unsaturated (olefinic products in general) generally less than 10% by weight.
• Typical fillers which can be advantageously treated according to the invention generally have a pour point above 0 ° C.
• the products resulting from the treatment according to the process have pour points of less than 0 ° C and preferably less than about -10 ° C.
• the hydrocarbon feedstock coming into contact with the catalyst based on ZBM-30 preferably at least 50% by weight of the feedstock at a boiling temperature at least 340 ° C, and even more preferably at least 60% by weight and better still at least 80% by weight of the charge at a boiling temperature of at least 340 ° C, preferably greater than at least 370 ° C and even more preferably greater than at least 380 ° C.
• This does not mean, for example, that the boiling point is 380 ° C and above, but 380 ° C or above.
• fillers suitable for the oil objective have an initial boiling point greater than at least 340 ° C and better still greater than at least 370 ° C and more preferably greater than at least 380 ° C.
• the reaction temperature is between 200 and 450 ° C and preferably between 200 and 420 ° C, preferably 250-410 ° C;
• the pressure is between 0J and 25 MPa and preferably between about 1 and 20 MPa;
• the hourly space velocity (wh expressed in volume of charge injected per unit volume of catalyst and per hour) is between approximately 0.05 and approximately 30 and preferably between approximately 0.1 and approximately 20 h ⁇ 1 and so even more preferred between about 0J and about 10 h-1.
• the rate of hydrogen used and expressed in liters of hydrogen per liter of charge is between 50 and about 2000 liters of hydrogen per liter of charge and preferably between 100 and 1500 liters of hydrogen per liter of charge.
• the catalytic dewaxing process according to the invention can be preceded by a hydroisomerization-hydrocon version step in the presence of a catalyst containing at least one noble metal deposited on an amorphous acid support.
• This hydroisomerization-hydroconversion step is optionally preceded by a hydrorefining step to remove the heteroatoms (oxygenated), this hydrorefining step can be followed by an intermediate separation.
• the hydroisomerization-hydroconversion stage takes place in the presence of hydrogen and in the presence of a bifunctional catalyst comprising an amorphous acid support (preferably an amorphous silica-alumina) and a hydro-dehydrogenating metallic function provided by at least one metal. noble of group VIII.
• the support is said to be amorphous, that is to say devoid of molecular sieves, and in particular of zeolite, as well as the catalyst.
• the amorphous acid support is advantageously an amorphous silica-alumina but other supports can be used.
• the catalyst generally does not contain any added halogen, other than that which could be introduced for the impregnation, of the noble metal for example.
• the silica-alumina can be obtained by any synthesis technique known to those skilled in the art such as co-precipitation techniques, cogelling ...
• the molecules of the feedstock to be treated for example n-paraffins
• a bifunctional catalyst undergo isomerization then optionally hydrocracking to lead respectively to the formation of isoparaffins and lighter crackers such as gas oils and kerosene.
• the conversion of products having boiling points greater than or equal to the initial boiling point of the feed which is at least 340 ° C, even 370 ° C or even better at least 380 ° C, into products with boiling points lower than the initial boiling temperature of the charge generally varies between 5 and 90%, preferably between 5 and 80% but is generally preferably less than 80% and better still less than 60%.
• the preferred support used for the preparation of the pretreatment catalyst by hydroisomerization-hydroconversion described in the context of this patent is composed of silica SiO 2 and alumina AI 2 O 3 .
• the silica content of the support is generally between 1 and 95%, advantageously even between 5 and 95% and preferably between 10 and 80% and even more preferably between 20 and 70% and between 22 and 45%. This silica content is perfectly measured using X-ray fluorescence.
• the metallic function is provided by a noble metal from group VIII of the periodic table of the elements and more particularly platinum and / or palladium.
• the noble metal content is between 0.05 to 10 and more preferably between 0J and 5.
• the distribution of the noble metal represents the distribution of the metal inside the catalyst grain, the metal being able to be well or badly dispersed.
• the distribution of platinum is good, i.e. the profile of platinum, measured according to the Castaing microprobe method, has a distribution coefficient greater than 0J and preferably greater than 0, 2.
• the BET surface of the support is between 100 m 2 / g and 500 m7g and preferably between 250 m 2 / g and 450m 2 / g and for supports based on silica-alumina, even more preferably between 310 m 2 / g and 450 m 2 / g.
• the preparation and the shaping of the support, and in particular of the silica-alumina, is done by usual methods well known to those skilled in the art.
• the support may undergo calcination such as for example a heat treatment at 300-750 ° C (600 ° C preferred) for 0.25-10 hours (2 hours preferred) under 0 -30% water vapor volume (for 7.5% alumina silica preferred).
• the noble metal salt is introduced by one of the usual methods used to deposit the metal (preferably platinum and / or palladium, platinum being more preferred) on the surface of a support.
• One of the preferred methods is dry impregnation which consists in introducing the metal salt into a volume of solution which is equal to the pore volume of the mass of catalyst to be impregnated.
• the catalyst may undergo calcination, for example a treatment in dry air at 300-750 ° C (520 ° C preferred) for 0.25-10 hours (2 hours preferred).
• the metal contained in the catalyst Before use in the hydroisomerization-conversion reaction, the metal contained in the catalyst must be reduced.
• One of the preferred methods for carrying out the reduction of the metal is the treatment under hydrogen at a temperature between 150 ° C and 650 ° C and a total pressure between 0J and 25 MPa. For example, a reduction consists of a plateau at 150 ° C for 2 hours then a rise in temperature to 450 ° C at the speed of 1 ° C / min then a plateau of 2 hours at 450 ° C; during this entire reduction step, the hydrogen flow rate is 1000 liters of hydrogen / liter of catalyst. Note also that all ex situ reduction method is suitable.
• the pressure will be maintained between 2 and 25 MPa and preferably 3 to 20 MPa and advantageously from 2 to 18 MPa, the space speed will be between 0J h " 1 and 10 h “ 1 , preferably between 0.2 and 10 h “1 and advantageously between 0.5 and 5.0h “ 1 .
• the hydrogen level is between 100 and 2000 liters of hydrogen per liter of charge and preferably between 150 and 1500 liters of hydrogen per liter of charge.
• the temperature used in this step is between 200 and 450 ° C and preferably from 250 ° C to 450 ° C advantageously from 300 to 450 ° C, and even more advantageously above 340 ° C, for example between 320-450 ° C .
• the two hydrorefining and hydroisomerization-conversion stages can be carried out on the two types of catalyst in different (two or more) reactors, and / or on at least two catalytic beds installed in the same reactor.
• the use of the catalyst described above in the hydroisomerization-hydroconversion stage has the effect of increasing the isomerization rate of the heavy fraction (340 ° C +, or even 370 ° C + and better still 380 ° C +) and decrease its pour point. More generally, it is found that the treatment of the hydroisomerization-hydroconversion stage then makes it possible to obtain better yields of the dewaxed oil fraction which will be obtained in the catalytic dewaxing step and to obtain the desired viscosimetric properties (viscosity and viscosity index VI).
• the effluent from the hydroisomerization-conversion step can be entirely treated in the dewaxing process according to the invention.
• This variant with passage through the catalytic dewaxing step of all of the effluent from the hydroisomerization-hydroconversion step, is economically advantageous, since a single distillation unit is used at the end of the process.
• a very cold diesel is obtained at the final distillation (after catalytic dewaxing or subsequent treatments) a very cold diesel is obtained.
• the effluent from the hydroisomerization-hydroconversion step may undergo separation of at least part (and preferably at least a major part) of light gases which include hydrogen and optionally also hydrocarbon compounds with at most 4 carbon atoms. Hydrogen can be separated beforehand.
• the effluent from the hydroisomerization-hydroconversion step is distilled so as to separate the light gases and also separate at least one residue containing the compounds with a boiling point greater than at least 340 ° C. It is preferably an atmospheric distillation.
• This fraction (residue) is then treated in the catalytic dewaxing step, that is to say without undergoing vacuum distillation.
• vacuum distillation can be used.
• middle distillates are called, the fraction (s) with an initial boiling point of at least 150 ° C. and a final going up to the residue, that is to say generally say up to 340 ° C, 350 ° C or preferably less than 370 ° C or 380 ° C.
• the effluent from the hydroisomerization-hydroconversion stage can undergo, before or after distillation, other treatments such as for example an extraction of at least part of the aromatic compounds.
• the effluent leaving the catalytic hydrodewaxing process according to the invention is advantageously sent to the distillation train, which preferably incorporates atmospheric distillation and vacuum distillation, which aims to separate the conversion products from point d boiling below 340 ° C and preferably below 370 ° C (and including in particular those formed during the catalytic hydrodewaxing step), and to separate the fraction which constitutes the oil base and whose initial point of boiling is greater than at least 340 ° C and preferably greater than or equal to 370 ° C.
• the distillation train which preferably incorporates atmospheric distillation and vacuum distillation, which aims to separate the conversion products from point d boiling below 340 ° C and preferably below 370 ° C (and including in particular those formed during the catalytic hydrodewaxing step), and to separate the fraction which constitutes the oil base and whose initial point of boiling is greater than at least 340 ° C and preferably greater than or equal to 370 ° C.
• this vacuum distillation section allows the different grades of oils to be separated.
• the effluent leaving the catalytic hydrodewaxing process according to the invention is, at least in part and preferably, in its entirety, sent to a hydrofinishing catalyst (hydrofinishing) in the presence of hydrogen so as to carry out a thorough hydrogenation of the aromatic compounds possibly still present which harm the stability of the oils and the distillates.
• a hydrofinishing catalyst hydrofinishing
• the acidity of the catalyst must be low enough not to lead to the formation of cracking product with a boiling point below 340 ° C. so as not to degrade the final yields, in particular of oils.
• the catalyst used in this hydrofinishing step comprises at least one metal from group VIII and / or at least one element from group VIB of the periodic table.
• metals are deposited and dispersed on a support of amorphous or crystalline oxide type, such as, for example, aluminas, silicas, silica-aluminas.
• the hydrofinishing catalyst (HDF) can also contain at least one element from group VII A of the periodic table.
• these catalysts contain fluorine and / or chlorine.
• the contents by weight of metals are between 10 and 30% in the case of non-noble metals and less than 2%, preferably between 0J and 1.5%, and even more preferably between 0J and 1.0 % in the case of noble metals.
• the total amount of halogen is between 0.02 and 30% by weight, advantageously between 0.01 and 15%, or even more advantageously between 0.01 and 10%, preferably between 0.01 and 5%.
• group VIII platinum and VIII for example
• halogen chlorine and / or fluorine
• the operating conditions under which the hydrofinishing step is carried out optionally according to the catalytic dewaxing process according to the invention are the following:
• the reaction temperature is between 180 and 400 ° C and preferably between 210 and 350 ° C, preferably 230-320 ° C;
• the pressure is between 0J and 25 MPa and preferably between 1.0 and 20 MPa;
• the hourly volume speed (vvh expressed in volume of charge injected per unit volume of catalyst and per hour) is between approximately 0.05 and approximately 100 and preferably between approximately 0J and approximately 30 h " '.
• the rate of hydrogen used and expressed in liters of hydrogen per liter of charge is between 50 and about 2000 liters of hydrogen per liter of charge and preferably between 100 and 1500 liters of hydrogen per liter of charge.
• the temperature of the hydrofinishing stage (HDF) is lower than the temperature of the catalytic hydrodewaxing stage (HDPC).
• the difference T HDPC -T HDF is generally between 20 and 200 ° C, and preferably between 30 and 100 ° C.
• the effluent leaving HDF is then sent to the distillation train.
• the base oils obtained in a process as described above have a pour point below -10 ° C., an VI greater than 95, preferably greater than 110 and even more preferably greater than 120, a viscosity of at least 3.0 cSt at 100 ° C., an ASTM color less than 1 and a UV stability such as l
• the ASTM color increase is between 0 and 4 and preferably between 0.5 and 2.5.
• Another advantage of this embodiment of the process according to the invention is that it is possible to achieve very low aromatic contents, less than 2% by weight, preferably less than 1% by weight and better still less than 0.05% by weight. ) and even go as far as the production of white oils of medicinal quality with aromatic contents of less than 0.01% by weight.
• These oils have UV absorbance values at 275, 295 and 300 nanometers respectively less than 0.8, 0.4 and 0.3 (ASTM D2008 method) and a Saybolt color between 0 and 30.
• the process according to the invention also makes it possible to obtain medicinal white oils.
• White medical oils are mineral oils obtained by a refined refining of petroleum, their quality is subject to different regulations which aim to guarantee their safety for pharmaceutical applications, they are devoid of toxicity and are characterized by their density and viscosity.
• Medicinal white oils mainly contain saturated hydrocarbons, they are chemically inert and their aromatic hydrocarbon content is low. Particular attention is paid to aromatic compounds and in particular to 6 polycyclic aromatic hydrocarbons (PAH for the English abbreviation of polycyclic aromatic hydrocarbons) which are toxic and present at concentrations of one part per billion by weight of aromatic compounds in l white oil.
• PAH polycyclic aromatic hydrocarbons
• the total aromatics content can be checked by the ASTM D 2008 method, this UV adsorption test at 275, 292 and 300 nanometers makes it possible to control an absorbance less than 0.8, 0.4 and 0.3 respectively (that is to say that the white oils have aromatic contents of less than 0.01% by weight). These measurements are carried out with concentrations of 1 g of oil per liter, in a 1 cm tank.
• the white oils sold are differentiated by their viscosity but also by their crude origin which can be paraffinic or naphthenic, these two parameters will induce differences both in the physicochemical properties of the white oils considered but also in their chemical composition.
• the dewaxing process of the present invention is advantageously used in the sequence of following stages: the load to be treated is separated (D1) into at least a light fraction 3 with a boiling point below 380 ° C, and at least one heavy fraction 4 (residue).
• said light fraction 3 optionally hydrogenated in a hydrotreatment step (HDT) is subjected to hydroisomerization (HISM)
• said heavy fraction 4 is subjected to a hydrocracking step (HCK) in the presence of hydrogen, then is subjected to a distillation (D2) to produce at least a light fraction (13) and at least a heavy fraction (10).
• the mixture resulting from hydroisomerization is fractionated (D3) at the same time as at least part of the light fraction 13 coming from the distillation D2 in order to obtain middle distillates having excellent cold properties, and / or a high cetane number and / or a reduced emission of polluting agents,
• the heavy fraction originating from D2 is subjected to a dewaxing stage (DWX) in order to obtain, after separation of the volatile products formed, an isomerized liquid product which can be used as a high quality lubricating base,
• DWX dewaxing stage
• a liquid stream 1 consisting of a mixture of linear hydrocarbons originating from a Fischer-Tropsch synthesis process, also comprising unsaturated products (olefins linear), in an amount up to 10% by weight, preferably 2 to 5% by weight, and oxygenated (especially alcohols) in an amount up to 10% by weight, preferably 2 to 7 % by weight, is separated in the distillation column D1 into a light fraction 3 with a boiling point below 380 ° C, preferably between 260 and 360 ° C and a heavy fraction 4, constituting the residue of the distillation.
• the distillation in D1 is preferably carried out in a single step (flash) and can be followed by a differential sampling of two fractions directly from the Fischer-Tropsch synthesis reactor.
• the mass ratio between the two fractions 3 and 4 is in the range from 0.5 to 2.0, even more preferably from 0.8 to 1.5.
• the light fraction 3 feeds a hydroisomerization unit (HISM).
• HISM hydroisomerization unit
• said fraction 3 preferentially feeds a hydrogenation unit ( HDT) in which it comes into contact with hydrogen (line 2) in the presence of a suitable catalyst, under conditions such as to minimize or even make the hydrocracking reaction absent.
• HDT hydrogenation unit
• the hydrogenation unit can be produced according to the usual techniques and preferably comprises a pressure reactor containing a fixed bed of catalyst selected to meet the specifications mentioned above.
• Typical hydrogenation catalysts suitable for the above specifications include a hydrogenating metal, such as nickel, platinum or palladium supported on an inert or acidic solid such as alumina, silica, silica-alumina, zeolite or molecular sieve. It is not excluded that during the hydrogenation also occurs a hydroisomerization reaction and a partial hydrocracking, generally limited to a conversion of less than 15% by weight of the total feed fraction.
• the small fraction of volatile compounds (150 ° C-) and the water possibly formed can optionally be separated by means of distillation.
• HISM hydroisomerization step
• the conditions suitable for isomerization are amply reported in the state of the art as well as an extensive list of usable catalysts.
• a portion normally less than 50%, preferably between 0 and 25%, of said light fraction can optionally be sampled by means of line 7, before the isomerization step and mixed again with said heavy fraction from line 4 to be sent to hydrocracking.
• the mixture of hydrocarbons is supplemented with hydrogen (line 5) in an amount between 150 and 1500 normal liters per liter of liquid and passes over a fixed bed of suitable catalyst, preferably based on metal. noble, with a space speed between 0J and 10 h-1 and a temperature between 300 and 450 ° C and a pressure between 1 and 10 MPa.
• the isomerized mixture is introduced via line 14 into a fractionation column D3 with the light fraction 13 coming from the column D2 for distillation of the heavy fraction sent to hydrocracking.
• a medium distillate is obtained in accordance with the embodiment, optionally taken at two different levels to separate the kerosene (line 17) from the diesel fuel (line 18), having excellent cold properties, a high index of cetane, preferably greater than 50 and a reduced emission of polluting agents.
• the amount of such volatile fractions is reduced significantly compared with analogous methods of the prior art, preferably less than 20%, more preferably less than 15% by weight relative to the initial feed of line 1.
• the fraction (line 4) of hydrocarbons with high boiling point and low content of oxygenated and unsaturated compounds is added with the necessary quantity of hydrogen ( line 8) and feeds a hydrocracking unit (HCK) produced by one of the usual techniques.
• a light fraction having a boiling point below 380 ° C, preferably below 350 ° C and comprising less than 10% by weight of volatile compounds (150 ° C-), consisting of a product having a concentration high in iso-paraffins, which comes through line 13 feeding the step of fractionation of the light fraction isomerized in HISM.
• a portion, preferably less than 50% by weight, of the mixture resulting from the distillation D2 is introduced via line 19 at the entry of the isomerization stage (HISM) in order to further increase the grade and distribution of the isomerized fractions and to regulate the relative amount of diesel and kerosene produced.
• the residual fraction from distillation D2 consists of a mixture of hydrocarbons with high boiling point having, surprisingly, a reduced content of waxes, compared to the products obtained with other catalysts of the prior art under conditions like.
• Such a residue can also be used as such for particular uses, but preferably comes to feed (line 10) a catalytic dewaxing or dewaxing (DWX) stage prior to its use as a lubricant base.
• DWX catalytic dewaxing or dewaxing
• this is partly recycled in the hydrocracking step (HCK) by means of line 12 in order to regulate the productivity of the process or to vary the degree of isomerization according to the requirements of production.
• Said dewaxing step (DWX) is carried out according to the method of the present invention in the presence of a catalyst adapted to the desired objective.
• the partially isomerized mixture still reacts in the presence of hydrogen and a suitable solid catalyst as described above, under the conditions of the process according to the invention.
• the quantities of linear paraffins being reduced, the dewaxing step according to the method of the present embodiment can be carried out under conditions of contact time and yield in particularly favorable lubricant base.
• the volatile products formed are separated (generally less than 3% by weight), an isomerized liquid product is recovered (line 11), with excellent cold properties and a high viscosity, having an initial boiling point greater than 350 ° C, preferably greater than 360 ° C which has an optimal composition for use as a high quality lubricant base.
• Catalyst C1 has a ZBM-30 zeolite. This catalyst is obtained according to the procedure described below.
• the ZBM-30 zeolite is synthesized according to BASF patent EP-A-46504 with the organic structuring agent triethylenetetramine.
• the raw synthetic ZBM-30 zeolite is subjected to calcination at 550 ° C. under a flow of dry air for 12 hours.
• the H-ZBM-30 zeolite (acid form) thus obtained has an Si / Al ratio of 45.
• the zeolite is kneaded with an alumina gel of type SB3 supplied by the company Condisputeda.
• the kneaded dough is then extruded through a die with a diameter of 1.4 mm.
• the extrudates thus obtained are calcined at 500 ° C for 2 hours in air.
• the H-ZBM-30 content by weight is 80% by weight.
• the support extrudates are subjected to a dry impregnation step with an aqueous solution of the platinum salt Pt (NH3) 42 +, 2OH-.
• the platinum content by weight of the catalyst C1 thus obtained is 0.52%.
• Example 2 Preparation of a C2 dewaxing catalyst not in accordance with the invention.
• Catalyst C2 contains a ZBM-30 zeolite. This catalyst is obtained according to the procedure described below.
• the ZBM-30 zeolite is synthesized according to BASF patent EP-A-46504 with the organic structuring agent hexamethylenediamine.
• the raw synthetic ZBM-30 zeolite is subjected to calcination at 550 ° C. under a flow of dry air for 12 hours.
• the H-ZBM-30 zeolite (acid form) thus obtained has an Si / Al ratio of 54.
• the zeolite is kneaded with an alumina gel of type SB3 supplied by the company Condisputeda.
• the kneaded dough is then extruded through a die with a diameter of 1.4 mm.
• the extrudates thus obtained are calcined at 500 ° C for 2 hours in air.
• the H-ZBM-30 content by weight is 80% by weight.
• the support extrudates are subjected to a dry impregnation step with an aqueous solution of the platinum salt Pt (NH3) 42 +, 2OH-.
• the platinum content by weight of the catalyst C1 thus obtained is 0.53%.
• Catalysts C1 and C2 the preparations of which are described in Examples 1 and 2, are used to improve the pour point of a charge consisting of paraffins from the Fischer-Tropsch synthesis with the aim of obtaining oils.
• the Fischer-Tropsch paraffins from the paraffin production unit are distilled so as to obtain a 370 ° C + cut.
• the main characteristics of the charge thus obtained are as follows: initial point 356 ° C point 5% 370 ° C point 10% 383 ° C point 30% 399 ° C point 50% 424 ° C point 80% 509 ° C point 90% 568 ° C 95% point 631 ° C pour point + 83 ° C density (20/4) 0.789
• the catalytic test unit comprises a fixed-bed reactor, with upward flow of charge ("up-flow"), into which 80 ml of catalyst C1 or C2 is introduced.
• the catalyst is then subjected to an atmosphere of pure hydrogen at a pressure of 10 MPa in order to ensure the reduction of the platinum oxide to metallic platinum, then the charge is finally injected.
• the total pressure is 10 MPa
• the hydrogen flow rate is 1000 liters of gaseous hydrogen per liter of charge injected
• the hourly volume speed is 1.1 h ⁇ 1
• the reaction temperature is 340 ° C.
• the effluents are divided into light products (petrol PI-150 ° C), middle distillates (150-370 ° C) and residue (370 + o C).
• EXAMPLE 4 Preparation of a Catalyst C3 for Pretreatment by Hydroisomerization of the Charge Resulting from the FT Process Subject to Dewaxing
• the pretreatment catalyst by hydroconversion-hydroisomerization C3 is prepared from a silica-alumina support used in the form of extrudates. It contains 40% by weight of silica SiO 2 and 60% by weight of alumina AI 2 O 3 .
• the silica-alumina before addition of the noble metal has an area of 332 m2 / g and its total pore volume is 0.82 ml / g.
• Catalyst C3 is obtained after impregnation of the noble metal on the support.
• the platinum salt H 2 PtCI 6 is dissolved in a volume of solution corresponding to the total pore volume to be impregnated. The solid is then calcined for 2 hours in air at 500 ° C. The platinum content is 0.48% by weight. Measured on the catalyst, the BET surface area is equal to 310 m 2 / g. The dispersion of platinum measured by H- / O 2 titration is 75%.
• the catalyst (C3) is used in order to hydroisomerize a charge of paraffins resulting from the Fischer-Tropsch synthesis in order to obtain oils.
• the paraffinic filler used in this example is the same as that used and described in example 3.
• the catalytic test unit comprises a fixed bed reactor, with upward flow of charge ("up-flow"), into which 80 ml of catalyst C3 is introduced.
• the catalyst is then subjected to an atmosphere of pure hydrogen at a pressure of 10 MPa in order to ensure the reduction of the platinum oxide to metallic platinum, then the charge is finally injected.
• the total pressure is 10 MPa
• the hydrogen flow rate is 1000 liters of gaseous hydrogen per liter of charge injected
• the hourly volume speed is 1.0 h -1 and the reaction temperature 350 ° C.
• the effluents are divided into light products (petrol PI-150 ° C), middle distillates (150-370 ° C) and residue (370 + o C).
• the residue (370 + o C) is then dewaxed in a second reactor with upward flow of charge ("up-flow"), into which 80 ml of catalyst C1 is introduced.
• the catalyst is then subjected to an atmosphere of pure hydrogen at a pressure of 10 MPa in order to ensure the reduction of the platinum oxide to metallic platinum, then the charge is finally injected.
• the total pressure is 10 MPa
• the hydrogen flow rate is 1000 liters of gaseous hydrogen per liter of charge injected
• the hourly volume speed is 1 J h '1
• the reaction temperature 335 ° C.
• the effluents are divided into light products (petrol PI-150 ° C), middle distillates (150-370 ° C) and oil fraction (370 + ° C). The characteristics of the oil obtained are measured.
• the use of a pretreatment step, upstream of the catalyst C1 according to the invention makes it possible to obtain a yield in oil fraction 370 ° C + having a pour point of - 21 ° C with a yield of 40.4% by mass while the catalyst C1 (compliant) used does not allow an oil fraction to be obtained with such a low pour point (it is only -9 ° C) and the yield in this oil fraction is lower 36.1% (see table in Example 3).
• the viscosity index and the VI of the oil fraction obtained with the pretreatment step and the catalyst C1 according to the invention are higher than in the absence of the pretreatment step.

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• 2003
  • 2003-07-03 FR FR0308152A patent/FR2857019B1/fr not_active Expired - Lifetime
• 2004
  • 2004-06-30 IT ITMI20041312 patent/ITMI20041312A1/it unknown
  • 2004-07-02 WO PCT/FR2004/001714 patent/WO2005012460A1/fr active Application Filing
  • 2004-07-02 RU RU2006103078/04A patent/RU2343184C2/ru not_active IP Right Cessation
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• 2005
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