FR2885136A1 - Pre-refining crude oil comprises fractionation into number of fractions, hydrotreating, hydrocracking or hydroconverting some fractions - Google Patents

Abstract

Pre-refining of crude oil (I) comprises: a first (F1) stage of fractionation by initial distillation to produce a first residue (R1) and at least a first non-asphaltenic stream (E1); a second (F2) stage of fractionation of at least part of (R1) to produce at least a second non-asphaltenic stream (E2), and an asphaltenic residue (R2); a stage of hydro-treating and/or hydroconversion and/or hydrocracking of at least part of (E2) to produce an effluent (HE2); optionally hydroconversion of at least a fraction of (R2). Pre-refining of crude oil (I), with hydrogenating catalytic treatment of one or more outlet cuts of (I) comprises: a first (F1) stage of fractionation by initial distillation to produce a first residue (R1) and at least a first non-asphaltenic stream (E1); a second (F2) stage of fractionation of at least part of (R1), by flash distillation and/or de-asphalting with solvent, to produce at least a second non-asphaltenic stream (E2), and an asphaltenic residue (R2); a stage of hydro-treating and/or hydroconversion and/or hydrocracking of at least part of (E2) to produce an effluent (HE2); optionally a stage of hydroconversion of at least a fraction asphaltenic outlet (R2), in which the fractionation stages and/or hydrogenating catalytic treatment of the process are carried out thus at least two non-asphaltenic effluent products from (I) have different ratios (R), as R is equal to 0.9N plus 0.5 VGO+ divided by MD plus 0.1 VGO+, where: N is naphtha wt.% of the boiling cut at 30-170[deg]C; MD is middle distillates wt.% of boiling cut with the top of 170-360[deg]C; VGO+ is wt.% of the boiling fraction with the top of 360[deg]C. The process further comprises: recomposing and producing, from the effluents, non-asphaltenic products from (I), optionally hydrocracking and/or hydrotreating and/or hydroconverting, at least two non-asphaltenic oils and having different ratios; producing at least a waste oil comprising the major asphaltenic part of (R2) or of residual asphaltenes after optional hydroconversion.

Description

Field of the invention

  The present invention relates to the petroleum industry, and the use of sulfur heavy refinery residues. Petroleum is traditionally processed in an oil refinery by a set of fractionation and chemical conversion operations to produce a set of commercial end products that meet specific technical standards or specifications, eg distillation intervals, sulfur contents , characteristic technical indices such as the octane number or the diesel index, etc ...

  The main commercial end products are petrochemical naphtha, gasoline, kerosene, diesel (also known as diesel fuel), domestic fuel oil, as well as various categories of more or less sulfur-containing fuel oils, road asphalts and liquefied petroleum gases. , and sometimes other products: lubricating oils, solvents, paraffin, fuel for a gas turbine, etc ... An oil refinery produces a relatively large number of commercial end products, from a number of crude oils , chosen according to their composition and their price.

  The evolution of the markets on the one hand, in particular the increasing competition of natural gas, and specifications on the discharges of combustion plants on the other hand (releases of oxides of sulfur, oxides of nitrogen, particles particularly in Europe) lead to a significant disadvantage for heavy sulfur oil fuels, for example heavy fuel oil with no more than 3.5% or 4% sulfur. Refiners are therefore faced with a very important technical problem, that of the use of refinery sulfur residues, given the regulatory provisions. These sulfur fuels are typically surplus and many countries tend to limit the sulfur content of fuels to 1% sulfur and in the future to 0, 5% or even 0.3%.

  Another trend in the use of petroleum products is a tendency to increase the consumption of middle distillates and petrol to the detriment of fuel oil, the increase in consumption of middle distillates being more significant than that of gasoline.

  The invention relates to a process for the pre-refining of petroleum, typically in the production region, to improve the quality of the oil with respect to these market developments.

  PRIOR ART The applicant has already proposed in the patent application FR04 / 02.088 to use typically inexpensive deposit gas to pre-refine a conventional oil, and typically to produce on the one hand a low-content oil Pa. sulfur and substantially free of asphaltenes, and secondly a residual oil Pb (including starting asphaltenes, partly converted by a hydrogenating treatment). Pa oil produced will, after refining, very little or no sulfur fuel, and may have a high content of middle distillates increasingly demanded by the market. It is a high quality oil. The oil Pb typically comprises lower quality fractions, and in particular the residual asphaltenes.

  The corresponding process is a pre-refining process for crude oil, that is to say a process producing, as final products, oils Pa, Pb, pre-refined (of improved quality, at least for Pa). These (pre-refined) oils are typically traded, disposed of and transferred to petroleum refineries. The pre-refining process also plans to possibly co-produce commercial final petroleum products: naphtha, diesel etc.

  This process of the prior art therefore produces a high quality oil Pa requested by the market. However, there remains a need to further improve the market suitability and quality of the proposed high quality oil to meet market needs and increase the value of the proposed product.

  SUMMARY OF THE INVENTION The invention provides a generally conventional crude oil pre-refining process for producing not two, but at least three pre-refined oils, Pa, Pb, Pc, two of which (Pa and Pb) are high quality oils, substantially free of asphaltenes, which will give after refining many high value products (naphtha, gasoline, middle distillates). On the contrary, Pc is a petroleum having a residue containing asphaltenes, and will give after refining significant amounts of fuel. According to an essential characteristic of the invention, the two oils Pa and Pb have different relative potentials with respect to the balance (naphtha + gasoline / middle distillates) after a conventional refining. Thus, a given refinery will be able to source not only its fuel needs (through the use of Pc petroleum), but also by modulating the distribution of its supplies of Pa and Pb oils to adapt perfectly to its clean market including the balance (naphtha + gasoline) / middle distillate. A refinery located primarily near urban areas will not have exactly the same gasoline / diesel distribution as a refinery located in a rural area. There will also be differences for a refinery located near a petrochemical cracking naphtha complex or for a refinery located near a mountain area (increased consumption of domestic fuel oil due to a colder climate). Thus, the invention makes it possible to finely stick to the market of each refinery. It thus allows, by introducing a means of adjustment to the market, a better access to this market and thus a better valuation of the high quality oils Pa and Pb proposed.

  This fine and efficient adjustment means is decoupled from the production of fuel, essentially related to the use of Pc residual oil. Thus, the naphtha + gasoline / middle distillate balance can be adjusted independently of fuel production.

  Detailed description of the invention

  The invention proposes a process for the pre-refining of oil, making it possible to produce, from a crude oil P (or several oils P1, P2, etc.), at least 3 pre-refined oils Pa, Pb, Pc. Pa and Pb are high quality oils, ie oils substantially free of asphaltenes. The process may also possibly produce more than 3 pre-refined oils, for example 3 or more asphaltene-free oils. It can also produce 2 or 3 residual oils (containing asphaltenes) or more. Nor would it be beyond the scope of the invention if the process made it possible to co-produce final or refined products: fuel, naphtha, kerosene, diesel fuel, domestic fuel, oils or oil bases, etc.

  The (or) crude oil P is typically conventional, but one can also use any type of crude oil, conventional, heavy, asphaltic, and in particular any oil of API degree between 5 and 50.

  The process uses a fractionation of the oil P by at least initial distillation (so-called "atmospheric"), and generally vacuum distillation. The initial distillation preferably separates at least two fractions, one relatively richer in middle distillates and the other relatively richer in naphtha (or at least having different naphtha / middle distillate ratios).

  The process also comprises at least one HDT hydrotreating or conversion unit, in particular VGO vacuum distillate hydrocracking. It often includes a vacuum residue deasphalting unit and a hydrotreating or hydrocracking unit of the deasphalted DAO oil produced. Finally, it usually includes an HDC residue hydroconversion unit.

  According to one of the essential characteristics of the invention, the fractionations, the conversions of the units and the distribution of the components of Pa and Pb are determined so that Pa is relatively rich in gasoline precursors and naphtha, and relatively poor in middle distillates. kerosene and diesel cut, while Pb, on the other hand, is a relatively poorer petroleum in petrol precursors and naphtha, and relatively richer in middle distillates.

  In particular, it is possible to characterize an oil substantially free of asphaltenes by the ratio: R = (0.9 N + 0.5 VGO +) / (MD + 0.1 VGO +), with: N = naphtha:% weight of the boiling cut (TBP distillation) between 30 C and 170 C.

  MD = middle distillates:% weight of the cup boiling above 170 C and below 360 C.

  VGO + =% by weight of the fraction boiling above 360 C. It should be noted that, for the oils Pa and Pb, VGO + denotes fractions (typically hydrotreated or hydrocracked) of unconverted VGO and DAO, which are non-asphaltenic ( substantially free of asphaltenes).

  If we look at the yields obtained from conventional oil refining, we arrive at the following conclusions: - Naphtha N can be converted into gasoline at about 90% by reforming and isomerization.

  VGO +, which is in this case devoid of asphaltenes and typically hydrotreated, can be converted to gasoline at approximately 50% by catalytic cracking (called FCC for "fluid catalytic cracking" which means fluid catalytic cracking).

  The term (0.9 N + 0.5 VGO +) is therefore (for a petroleum without asphaltenes) a good indicator of the petrol potential of petroleum during its subsequent refining.

  Moreover, it is generally possible to incorporate 10% by weight of catalytic cracking gas oil (often called LCO for "light cycle oil" or "light cyclic oil") for middle distillates, the remainder of the LCO being used as fluxing agent (diluent) for fuels. The term (MD + 0.1 VGO +) is therefore a good indicator of the potential for middle distillates of petroleum during its subsequent refining.

  Therefore, the R ratio characterizes the gasoline potential versus the middle distillate potential: A high R ratio oil will produce relatively more gasoline, while a low R ratio oil will produce relatively more middle distillates.

  Typically according to the invention, the ratio Ra for the oil Pa is greater than the ratio Rb for the oil Pb. This can be easily obtained, for example by incorporating relatively more naphtha N and / or unconverted VGO in Pa than in Pb and, on the contrary, by incorporating more middle distillates MD into Pb than into Pa. The decomposition of the initial petroleum into fractions having different contents of naphtha, middle distillates and VGO + makes it possible an easy recomposition making it possible to enrich one or the other. Other oils Pa, Pb in middle distillates or petrol precursors. For the effluents from the conversion units, it is possible to adapt the conversion and / or measure the VGO + content of the effluents (by distillation, chromatographic analysis, etc.) to assess their contents of naphtha, middle distillates, and VGO +, in order to perform the desired redialing of Pa and Pb.

  In general, the invention proposes a process for the pre-refining of at least one crude oil P with catalytic hydrogenation treatment of one or more cuts from P comprising: at least a first stage F1 of fractionation by initial distillation PRE -DIST to produce a first residue R1 and at least a first non-asphaltenic (light) stream E1, - at least a second stage F2 fractionation of at least a portion of R1 (i.e. a fraction of R1 or a fraction derived from R1), by vacuum distillation VAC-DIST and / or by solvent deasphalting SDA, to produce at least a second non-asphaltenic stream E2, and an asphaltenic residue R2, at least one hydrotreatment stage HDT and / or hydroconversion HDC and / or HDK hydrocracking of at least a portion of E2 to produce an effluent HE2, - optionally a hydroconversion step RHDC of at least one asphaltenic fraction from R2, in which the fractional steps and / or hydrogenating catalytic treatment of the process are determined so that at least two non-asphaltenic effluents produced from P have different R ratios, with: R = (0.9 N + 0.5 VGO +) / (MD + 0.1 VGO +), with: N = naphtha:% weight of the cup boiling between 30 C and 170 C; (eg N = 25 if there is 25% by weight of naphtha in the effluent or hydrocarbon stream under consideration); MD = middle distillates:% weight of the cup boiling above 170 C and not more than 360 C; VGO + =% weight of the fraction boiling above 360 C; the method further comprising the steps of: a) recomposing and producing from non-asphaltenic effluents (substantially without asphaltenes) produced from P, optionally hydrotreated and / or hydroconverted and / or hydrocracked, at least two non-asphaltenic oils Pa and Pb having R ratios, ie Ra and Rb, which are different, b) producing at least one Pc residual oil comprising at least a majority of the asphaltenes of the asphaltenic residue R2 or at least residual asphaltenes after RHDC hydroconversion if the process includes such a step. It would not be departing from the scope of the invention if not one but several residual oils Pc1, Pc2, were produced. ..including overall most of the aforementioned asphaltenes.

  Typically, Pa and Pb are essentially formed from fractions from the group of following cuts from P, optionally hydrotreated and / or hydroconverted and / or hydrocracked: naphtha N, middle distillates MD, intermediate gas oil IGO, light vacuum distillate LVGO, heavy HVGO or total VGO, deasphalted oil DAO, with the respective distillation intervals TBP: N: [30 C / 170 C]; MD:] 170 C / 360 C]; IGO: [340 C / 420 C]; LVGO:] 360 C / 450 C]; HVGO:] 450 C / 565 C]; VGO:] 360 C / 565 C]; DAO:> 565C

  The fractionations are not perfect, it would not depart from the scope of the invention if the aforementioned cuts were for example composed of at least 50% by weight of compounds in the respective distillation intervals mentioned: Typically, 1.10 <Ra / Rb <4.5. Most often, 1.15 <Ra / Rb <4. Preferably, 1.3 <Ra / Rb <3. Very preferably, 1.4 <Ra / Rb <2.5.

  In general, 0.7 <Ra <2.0. Most often, 0.8 <Ra <1.7. Preferably, 1.3 <Ra <3. Very preferably, 1.4 <Ra / Rb <2.5.

  Preferably, 1.0 <Ra <1.5 and 0.35 <Rb <0.9. In general, 0.8 <Ra <1.7 and 0.3 <Rb <1.0.

  Preferably, Pc comprises at least the majority of the effluent of a RHDC hydroconversion of R2 bubbling bed.

  According to one of the variants of the invention, R2 is a vacuum distillate VGO.

  According to another variant of the invention, R2 is asphalt AS obtained by solvent deasphalting SDA. In this case, AS is often hydroconverted in bubbling bed, supplemented with a liquid diluent DIL comprising at least 30% by weight of compounds boiling below 340 C.

  Typically, the amount of diluent is between 4% and 40% by weight of AS, preferably between 5% and 30% by weight of AS, and very preferably between 6% and 25% by weight of AS.

  DIL generally comprises from 3% to 25% by weight, preferably from 4% to 20% by weight of 10 AS, and very preferably from 5% to 15% by weight of fractions boiling up to 360C.

  The solvent used for deasphalting is preferably relatively heavy (significantly heavier than propane) and therefore produces asphalt asphaltenes. Suitable solvents include all mainly paraffinic (optionally olefinic) hydrocarbons having from 3 to 7 carbon atoms. But very preferably they include propane-butane mixtures, butane, pentane, hexane, heptane, light gasoline and mixtures obtained from the aforementioned solvents. Preferred solvents include butane, pentane, hexane and mixtures thereof. The most preferred solvents include butane, pentane and mixtures thereof.

  The operation of solvent deasphalting SDA can be carried out under conventional conditions: One can thus refer to the article by BILLON et al. Published in 1994 in volume 49, No. 5 of the review of the Institut Français du Pétrole P 495-507, the book "Refining and Conversion of Heavy Oil Products" by J.-F. Page, SG Chatila and M. Davidson, TECHNIP Editions, p 17-32, or to the description given in the patent FR-B-2 480 773 or in the patent FR-B-2 681 871 or in the patent application US-A-4,715,946. The deasphalting can in particular be carried out at a temperature of between 60 ° C. and 250 ° C. with one of the abovementioned solvents, optionally supplemented with an additive. The solvents used and the additives are described in particular in the abovementioned documents and in patent documents US-A-1,948,296; US Patent 2,081,473; US Patent 2,587,643; US Patent 2,882,219; US-A-3,278,415 and US-A-3,331,394. The solvent can be recovered by vaporization or distillation or by the opticritic process, that is to say under supercritical conditions. The deasphalting can be carried out in a mixer-settler or in an extraction column.

  According to another variant of the invention, the asphalt is not converted: the untreated asphalt AS is directly mixed with one or more petroleum fractions, typically derived from P, to form the Pc oil, the vacuum residue of which contains then virgin asphaltenes in increased amount relative to the vacuum residue of petroleum P. Typically, these petroleum fractions comprise at least one fraction of crude oil which is mixed with AS.

  According to an alternative embodiment of the invention, Pa, Pb and Pc are formed in such a way that the percentage of compounds boiling between 360 ° C. and 400 ° C. with respect to the VGO fraction is lower for Pb than for P, as well as for at least one of the oils Pa, Pc. For example, an IGO or LVGO fraction is oriented after hydrotreatment or light hydrocracking preferably to Pa and / or Pc than to Pa. It is also possible to convert more than 50% or more than 70% of IGO or LVGO to a conversion and to feed the mixture. effluent more importantly to Pa and / or Pc. This relative depletion of Pb compounds boiling between 360 C and 400 C, makes it easier to distill the middle distillates of Pb (fractionation MD / VGO) and thus to be able to incorporate in Pb increased amounts of middle distillates MD without posing any problem of Pb refining at the initial distillation.

  According to the invention, Pa, Pb, and Pc are three oils, end products of the pre-refining process, each intended to be used as the initial distillation feedstock of one or more petroleum refineries.

  Pa, Pb, and Pc are end products of the pre-refining process, which are conventional oil refinery feeds and not end products or intermediate refining products, or end products for a particular use. They each typically comprise at least 6% by weight of naphtha N, at least 10% by weight of middle distillates MD (for example at least 4% by weight of kerosene] 170 C / 250 C] and at least 6% by weight of diesel cutter 250 C / 360 C]), and at least 10% by weight of vacuum distillate VGO.

  Generally, at least the majority of Pa and Pb are separately transported by pipelines and oil boats for use as initial distillation feeds of one or typically several petroleum refineries.

  In general, 0.7 <Ra <4.0. Most often, 0.8 <Ra <3. Preferably, 1.3 <Ra <2.8. Very preferably, 1.4 <Ra / Rb <2.5.

  Preferably, 1.0 <Ra <1.5 and 0.35 <Rb <0.9.

  9 In general, 0.8 <Ra <1.7 and 0.3 <Rb <1.0.

  The invention makes it possible to flexibly recompose each of the non-asphaltenic oils Pa and Pb. Considering indeed the oil Pa having the greatest relative potential in gasoline, the percentage of naphtha, that of distillates, can be chosen as desired. MD means and that in non-asphaltenic VGO +. It is therefore possible to arbitrarily determine the ratio R by varying these components. It has also been found that it may be particularly advantageous, vis-à-vis the valorization of the starting oil, to produce a reconstituted oil having not only a high R ratio, but also having a high gasoline potential. Such oil will have an excellent valuation in Japan or the United States of America.

  The invention therefore also relates to a non-asphaltenic reconstituted oil Pa, comprising at least 30% by weight of naphtha N, having a ratio R greater than or equal to 1.7 and a gasoline potential POTe of between 50 and 70, with POTe = 0 , 9 N + 0.5 VGO +.

  Such reconstituted petroleum may in particular comprise between 30% and 50% by weight of naphtha N, have a ratio R between 1.75 and 2.5 and a gasoline potential POTe of between 55 and 70.

  This reconstituted petroleum Pa may finally comprise between 36% and 50% by weight of naphtha N, have a ratio R between 1.80 and 2.5 and a petrol potential POTe of between 58 and 70.

  Such reconstituted oils can easily be obtained by varying the contents of naphtha, middle distillates and VGO + at the time of recomposition of Pa, Pb, Pc.

  For example, if we recompose Pa with 35% by weight of naphtha N, 25% by weight of middle distillates MD and 40% by weight of VGO + non-asphaltenic, we will have: R = (0.9 * 35 + 0.5 * 40) / (25 + 0.1 * 40) = 1.776; And POTe = (0.9 * 35 + 0.5 * 40) = 51.5.

  If naphtha is increased and the middle distillates are lowered, R and POTe can easily be varied. Take for example: Pa with 40% by weight of naphtha N, 20% by weight of middle distillates MD and 40% by weight of non-asphaltenic VGO +, we will have: R = (0.9 * 40 + 0.5 * 40) / (20 + 0 , 1 * 40) = 2.33; And POTe = (0.9 * 40 + 0.5 * 40) = 56.

  It is therefore easy to recomposer according to the invention non-asphaltenic oils having variable R and POTe ratios, especially high, by adjusting their composition, and by directing the surplus sections to the other recomposed oils Pb, Pc.

Description of Figure 1

  Referring now to Figure 1 which shows an installation diagram for carrying out the method according to the invention.

  A crude oil P, typically conventional (for example light Arabic), is fed via line 1 into a desalter 2. The desalinated oil feeds via line 3 a PRE-DIST preliminary distillation column, referenced 4 (often called initial distillation or atmospheric distillation) typically operating at a pressure of between 0.1 and 0.5 MPa. This column, which can eventually produce a brief fractionation, produces a light stream, typically of naphtha and lighter compounds, through line 30, a middle distillate stream MD, typically kerosene and diesel cut through line 5, and a stream of intermediate gas oil IGO line 6, which may include fractions boiling mainly between 340 C and 420 C. This intermediate gas, relatively heavy for an atmospheric column can be obtained through a large stripping steam.

  Column 4 also produces an atmospheric residue via line 7, which feeds a VAC-DIST vacuum distillation column referenced 8. This column, which typically operates at a pressure of between 0.004 and 0.04 MPa, produces a distillate stream. VGO vacuum through line 10, and a vacuum residue stream VR through line 9. It can also optionally produce a LVGO light vacuum distillate stream through line 11.

  The vacuum residue VR is fed into a SDA unit referenced 12 of solvent deasphalting (preferably pentane) to produce a deasphalted DAO oil circulating in line 13 and a stream of asphalt AS discharged via line 14.

  The asphalt AS is mixed with a stream of diluent DIL fed through line 15. This stream typically comprises a desalinated petroleum stream fed from line 3 via line 15 and / or a medium distillate stream MD fed from line 5 via line 22 and / or an IGO intermediate gasoline stream supplied from line 6 via lines 23 and 22. DIL may also comprise naphtha N taken from line 30. The diluent flow rate relative to the asphalt flow rate AS is typically between 3 and 50% by weight, preferably between 4 and 40% by weight, in general between 5 and 30% by weight and most preferably between 6 and 26% by weight.

  The mixture of asphalt and diluent (fluxed asphalt) then feeds the boiling bed hydroconversion unit HDC referenced 16. This unit typically comprises at least 2, and preferably at least 3 bubbling bed reactors arranged in series.

  At the outlet of the HDC unit, the hydroconversion effluent is added by several currents flowing in the lines 30c, 31c, 32c, 33c, and 34c. These streams typically comprise naphtha N (line 30c), hydrotreated middle distillates MD (line 31c), hydrotreated or hydrocracked IGO intermediate gas (generally partially) (line 32c), hydrotreated or hydrocracked VGO vacuum distillate (generally partially) (line 33c), hydrotreated or hydrocracked deasphalted oil (usually partially) (line 34c). A (pre-refined) Pc oil is thus reconstituted from the hydroconversion effluent, which comprises unconverted asphaltenic fractions, and non-asphaltenic fractions that are typically hydrotreated or hydrocracked, and therefore have a reduced sulfur content. This Pc oil has a significantly lower sulfur content than that of the initial oil P. The fractions MD, IGO, VGO, DAO are then hydrotreated and / or hydrocracked (typically partially) in the units H1 referenced 21, H2 referenced 20, H3 referenced 19 and H4 referenced 18. Typically, H1 (and often H2) is a hydrotreatment HDT, and H3 and H4 are mild hydrocracking units: M-HDK, medium pressure: MPHDK, or high pressure: HP-HDK. Preferably, H4 is bubbling bed hydrocracking.

  The light current flowing in line 30 is subdivided into 3 elementary currents 30a, 30b, 30c.

  The effluent of H1 circulating in the line 31 is subdivided into 3 elementary currents 31a, 31b, 31c.

  The H2 effluent circulating in the line 32 is subdivided into 3 elementary currents 32a, 32b, 32c.

  The effluent of H3 circulating in the line 33 is subdivided into 3 elementary currents 33a, 33b, 33c.

  The effluent of H4 circulating in the line 34 is subdivided into 3 elementary streams 34a, 34b, 34c.

  From the streams 30a, 31a, 32a, 33a, and 34a is formed by mixing a pre-refined oil Pa. Pa is an oil substantially free of asphaltenes since each of its components is also (asphaltenes are only contained in the current AS). It is also a very low sulfur oil since most of its components are desulfurized, and naphtha, fed via line 30a, is typically low in sulfur (it can also be hydrotreated, optional).

  Analogously, from the streams 30b, 31b, 32b, 33b, and 34b, a pre-refined petroleum Pb is formed by mixing. For the same reasons as for Pa, Pb is also an oil substantially free of very low-temperature asphaltenes. sulfur content.

  According to the invention, the conversions of the units and the distribution of the Pa and Pb components are determined so that Pa is relatively rich in gasoline and naphtha precursors, and relatively poor in middle distillates: kerosene and diesel cut while Pb, at The opposite is a relatively poorer oil in petrol precursors and naphtha, and relatively richer in middle distillates.

  Typically according to the invention, the ratio Ra for the oil Pa is greater than the ratio Rb for the oil Pb. This can be done easily, for example by incorporating relatively more naphtha N and unconverted VGO + in Pa (via the lines 30a). and 33a) than in Pb (via lines 30b and 33b), and on the contrary by incorporating more middle distillates MD into Pb (via line 31b) than into Pa (via line 31a). The decomposition of the initial petroleum into fractions makes it easy to recomposition which makes it possible to enrich one or the other of the oils Pa, Pb in middle distillates or petrol precursors. For the effluents from the conversion units, it is possible to adapt the conversion and / or measure the VGO + content of the effluents (by distillation, chromatographic analysis, etc.) to assess their VGO + contents.

  In general, the recomposition of the oils Pa and Pb is carried out so that Ra / Rb is greater than 1.08 or even 1.12 or 1.2, in particular between 1.08 and 3.0; often between 1.12 and 2.50; preferably between 1.20 and 2.0; and very preferably between 1.25 and 1.80.

  The invention can, before recomposing the oils Pa, Pb, Pc, implement one or more catalytic steps using certain methods well known in the state of the art, including desulfurizing treatments, under hydrogen pressure, which consume significant or high amounts of hydrogen.

  According to the invention will be called "hydrogenating catalytic treatment" a treatment comprising at least one of the treatments defined below and symbolized by the following names: HDT, HDC, HDK (which covers MHDK, MP-HDK and HP-HDK) , RHDT, HRSDC. The following treatments are therefore distinguished: a) Hydrotreatments (symbolically designated by the abbreviation HDT) of asphaltenes-free feeds: Hydrotreatments of hydrocarbon distillates or deasphalted oil (fillers substantially free of asphaltenes) are well-known processes of the invention. state of the art. Their main purpose is the at least partial elimination of undesirable compounds, typically sulfur, nitrogen, possibly metals such as iron, nickel or vanadium, etc. They are also often used for the hydrogenation of aromatics, usually simultaneously with the desulfurization of the feedstock.

  Conventionally, for those of the abovementioned fillers which comprise compounds boiling above 371 C, the term "hydrotreatment" refers to a process in which the conversion of these compounds to compounds with a boiling point below 371 C is less than or equal to 20% by weight. . For processes treating the same feedstocks, but with a conversion greater than 20% by weight, it will be called hydroconversion (symbolically designated by the acronym HDC), or hydrocracking (symbolically denoted HDK), these processes being presented below.

  The hydrotreating processes operate under hydrogen pressure, and use supported solid catalysts, typically granular solids or extrudates of characteristic size (diameter for balls or equivalent diameter (corresponding to the same section) for extrusions) between 0.4 and 5 mm, in particular between 1 and 3 mm, the operating conditions, and in particular the space velocity (VVH) and the molar ratio hydrogen on hydrocarbon (H2 / HC) vary according to the cuts treated, the impurities present and the final specifications sought.

  Typical and non-limiting examples of operating conditions are given in the following table: Cup Point Speed Pressio Temperature Report Spatial consumption n of H2 e start of H2 / HC n of H2 oil cut (h-1) (bar) cycle (C) (Nm3 / m3) (wt%) (C) Naphtha 70-180 4-10 5260-300 100 0.05-0.01 Kerosene 160-240 2-4 15-30 300-340 150 0.01 -0.02 Diesel and Gas oil 230-371 1-3 20-40 320-350 150-300 0.3-0.8 Vacuum gas oil 371-565 1-2 40-70 360-380 300-500 0.4 -0.9 Oil> 565 0.5-1.5 50110 360-380 500-1000 0.5-1 deasphalted Hydrotreating catalysts typically comprise a metal, or compound of a Group VIB metal and a metal or compound of a Group VIII metal, on a support.

  The most common catalysts are composed of an oxide carrier and an active phase in the form of molybdenum sulfide or tungsten promoted by cobalt or nickel. The commonly used formulas are the CoMo, NiMo and NiW combinations for the active phase, and the high surface area alumina for the support. The metal contents are often of the order of 9 to 15% by weight of molybdenum and 2.5 to 5% by weight of cobalt or nickel.

  Some of these catalytic formulas are sometimes doped with phosphorus. Other oxide supports are employed, such as mixed oxides of silica-alumina or titanium-alumina type.

  These supports are typically of low acidity, to obtain acceptable catalytic cycle times.

  Typical examples of catalysts and hydrotreatment, in particular diesel, gas oil or vacuum gas oil cuts are the catalysts HR448 and HR426 of the French company AXENS.

  When traces of metals, in particular nickel and vanadium, are present in the feedstock, a catalytic support comprising a porosity adapted to the deposition of these metals is advantageously used.

  An example of such a catalyst is HMC 841 from AXENS.

  For the hydrotreatment of a deasphalted oil (DAO) comprising metals, it will be possible, for example, to use a first bed with an HMC 841 catalyst, for the demetallization, then a second bed of HR 448 for the desulfurization and denitrogenation.

  Other technical elements relating to hydrotreating can be found in the reference work: "Conversion processes", P. Leprince, 10 Editions Technip, Paris 15th, pages 533-574.

  b) Hydrocracking processes (symbolically designated by the abbreviation HDK) of asphaltene-free feeds: Hydrocracking processes are also methods that are well known in the state of the art. They apply exclusively to charges substantially free of asphaltenes or metals such as nickel or vanadium.

  The hydrocracking feedstock is typically composed of vacuum gas oil, sometimes supplemented with gas oil and / or deasphalted oil (deasphalted vacuum residue, typically with a solvent from the group formed by propane, butane, pentane and mixtures thereof, and preferably propane and butane).

  It is also possible to hydrocrack DAO deasphalted oil. The DAO must then be of sufficient quality: typically, a hydrocracking feedstock comprises less than 400 ppm (parts per million by weight) of asphaltenes, preferably less than 200 ppm and most preferably less than 100 ppm. The metal contents (typically nickel + vanadium) of a hydrocracking feedstock are typically less than 10 ppm, preferably less than 5 ppm, and most preferably less than 3 ppm. Conventionally, it is considered that a load is substantially without asphaltenes if its asphaltenes content is less than 400 ppm. (For a pre-refined oil, it is considered in a similar way that it is asphaltenes-free, or non-asphaltenic, if the fraction boiling above 524 C contains less than 400 ppm of asphaltenes).

  Typically the hydrocracking feedstock is first pre-refined on a hydrotreatment catalyst, typically different from the hydrocracking catalyst. This catalyst, typically of acidity lower than that of the hycrocracking catalyst, is chosen to substantially eliminate the metals, reduce the traces of asphaltenes, and reduce the organic nitrogen, which inhibits the hydrocracking reactions, to a value of typically less than 100 ppm, preferably 50 ppm and very preferably less than 20 ppm.

  Hydrocracking catalysts are typically bifunctional catalysts having a dual function: acid on the one hand and hydrogenating / dehydrogenating on the other hand. Typically, the support has a relatively high acidity such that the ratio of hydrogenating activity on isomerizing activity H / A as defined in French Patent No. 2,805,276 pages 1 line 24 to page 3 line 5, is greater than 8, or preferably greater than 10 or very preferably greater than 12, or even greater than 15. Typically, a hydrotreatment is carried out upstream of the reactor or the hydrocracking zone with a hydrotreatment catalyst whose aforementioned H / A ratio is less than 8, especially less than 7.

  The hydrocracking catalysts typically comprise at least one Group VIB metal or metal compound (such as Mo, W) and a metal or Group VIII metal compound (such as Ni ...) deposited on a support. The atomic ratio of the group VIII metal (Mv111) on the sum of the metals of groups VIII and VI B, ie the atomic ratio Mv111 / (MV111 + MN, B), in particular for the NiMo and NiW pairs is often close to 0.25, for example between 0.22 and 0.28.

  The metal content is often between 10 and 30% by weight.

  The metal of group VIII may also be a noble metal such as palladium or platinum, at levels of the order of 0.5 to 1% by weight.

  The acidic support may comprise a halogen-doped alumina, or a silica-alumina having a sufficient acidity, or a zeolite, for example a dealuminated Y or USY zeolite, often having a double pore distribution with a double porosity network comprising in particular micropores of size mainly comprised between 4 to 10 A and mesopores of size mainly between 60 and 500Â. The silica / alumina ratio of the structure of the zeolite is often between 6.5 and 12. By way of example, it is possible to use a hydrotreatment and hydrocracking sequence with the catalysts HR 448 (HDT) and then HYC 642 (HDK) marketed by the French company AXENS. If the feedstock comprises metals, it will be possible to use upstream of these two catalytic beds a bed of demetallization catalyst such as the HMC 841 catalyst also marketed by AXENS.

  Examples of operating conditions for hydrocracking are typically: - space velocity VVH between 0.3 and 2 h -1, - temperature between 360 and 440 C, - hydrogen recycling between 400 and 2000 Nm3 per m3de load, - The Hydrogen partial pressure and total pressure can vary significantly depending on the charge and conversion desired. By convention, a conversion greater than or equal to 20% by weight and less than 42% by weight corresponds to a mild hydrocracking (symbolically denoted M-HDK); a conversion greater than or equal to 42% by weight and less than 60% by weight corresponds to a medium pressure hydrocracking (symbolically noted MPHDK); a conversion greater than or equal to 60% by weight (and typically less than 95% by weight corresponds to a high-pressure hydrocracking (symbolically denoted HP-HDK).

  By definition, the conversion is that of products with a boiling point greater than 371 C, products boiling below 371 C.

  Typically, the hydrogen partial pressure is, depending on the feedstock, often between about 2 MPa and 6 MPa for mild hydrocracking, between about 5 MPa and 10 MPa for medium pressure hydrocracking, and between about 9 MPa and 17 MPa. MPa for high pressure hydrocracking. The total pressure is often between 2.6 and 8 MPa for mild hydrocracking, between about 7 and 12 MPa for medium pressure hydrocracking, and between 12 and 20 MPa for high pressure hydrocracking.

  The hydrocracking processes are typically operated in a fixed bed with granular solids or extrudates of characteristic dimension (diameter for balls or equivalent diameter (corresponding to the same section) for extrusions) of between 0.4 and 5 mm, in particular between 1 and 3 mm. It would not be departing from the scope of the invention if the hydrocracking was carried out in a moving bed (granular catalyst bed typically in the form of extrudates or, preferably, beads, of dimensions similar to those described for a fixed bed.

  Further technical elements relating to hydrocracking can be found in the reference book: "Hydrocracking Science and Techn000gy", J Scherzer and AJ Gruia, Publisher Marcel Dekker, New York, and in the reference work: "Conversion processes", P. Leprince, Technip Publishing, Paris 15th, pages 334-364.

  c) The hydroconversion processes (symbolically designated by the HDC siqle) of a non-asphaltene (e.g., DAO type) but containing significant amounts of metals (Ni, V): Such methods are known to achieve conversions (with the same definition as for hydrocracking) higher than 20% by weight and often much higher (for example from 20% to 50%, or from 50% to 85% by weight, for example ebullated bed processes. processes can use variable partial pressures of hydrogen, for example between 4 and 12 MPa, temperatures between 380 and 450 C, and a recycling of hydrogen for example between 300 and 1000 Nm3 per m3 of feedstock, the catalysts used are similar or similar to that of the hydrotreating or hydroconversion catalysts residues, defined below, and have a porosity to have a significant capacity for demetallization.

  One can for example use a catalyst of the HTS 358 type, marketed by the French company AXENS.

  d) Hydrotreatments of residues (symbolically designated by the initials RHDT) or hydroconversions of residues (symbolically designated by the acronym RHDC): The processes of hydrotreatment of residues (and hydroconversion of residues are well known processes of the state of the technique.

  The operating conditions of these processes are typically: hourly space velocity (or VVH) of between 0.1 and 0.5. H2 partial pressure between 1 and 1.7 MPa. Hydrogen recycling between 600 and 1600 Nm3 per m3 of load. Temperature between 340 and 450 C. The catalysts of the fixed-bed, mobile or bubbling methods are most often supported macroscopic solids, for example beads or extrudates with a mean diameter of between 0.4 and 5 millimeters. Typically they are supported catalysts comprising a metal or metal compound of group VIB (Cr, Mo, W) and a metal or metal compound of group VIII (Fe, Co, Ni, ...) on a mineral support, by example catalysts based on cobalt and molybdenum on alumina, or nickel and molybdenum on alumina.

  For a hydrotreatment or a hydroconversion in a fixed bed, it is possible to use, for example, a hydrodemetallization catalyst HMC 841, and then hydroconversion and hydrocracking catalysts: HT 318 and then HT 328 marketed by the French company AXENS. For a bubbling bed, it is possible to use a catalyst of the HOC 458 type, also marketed by the French company AXENS.

  The catalysts of the slurry processes are more diverse and may comprise particles of ground coal or lignite impregnated with iron sulphate or other metals, ground spent hydrotreating catalyst, molybdenum sulphide particles associated with a hydrocarbon matrix obtained by in situ decomposition of precursors such as molybdenum naphthenate, etc. The particle sizes are typically less than 100 microns, or even much smaller.

  Other characteristics of the processes and catalysts for hydroconversion of residues are given in the general work referenced A: "Refining and conversion of heavy oil products", by JF Le Page, SG Chatila, M Davidson, Technip Publishing, Paris , 1990, in Chapter 4 (Catalytic Conversion under Hydrogen Pressure), and Chapter 3, paragraph 3.2.3. Reference may also be made to the general work referenced B: "Conversion processes", P. Leprince, Technip Publishing, Paris 15th, pages 411-450., In Chapter 13 (hydroconversion of residues), and the general work: "upgrading petroleum residues and heavy oils" which means improving the quality of petroleum residues and heavy oils, by Murray R. Gray, publisher Marcel Dekker Inc. New York, chapter 5.

  Hydrogen production, for the implementation of these various hydrogenating catalytic treatments, can be carried out from purified gas for example by steam reforming on nickel catalyst and then conversion of CO to steam and purification is a well known method, described in the aforementioned reference work B, p 451-502, or in the reference work: "The Desulphurization of Heavy Oils and Residua", J Speight, Publisher Marcel Dekker, Inc. . New York.

Examples

  The yields of the following examples are expressed without regard to sulfur, in weight relative to the feed.

  Example 1 According to the Prior Art: A Middle East oil P is pre-refined by carrying out the following operations: a) P is fractionated by atmospheric distillation and then under vacuum to produce 4 sections: a n-cut of naphtha and lighter component representing 20% by weight of P, of which 18% naphtha and 2% lighter compounds; an MD cup of middle distillates representing 25% by weight of P; a VGO fraction of vacuum distillate representing 35% by weight of P; a fraction VR slice of vacuum residue representing 20% of P. hydrotraite (HDT) MD, and converts VGO to a 25% conversion of which 1% C4- 5% naphtha gas and 19% middle distillates, by hydrocracking sweet M-HDK.

  Hydroconversion in RHDC bubbling bed is converted into the vacuum residue VR at 60% conversion to VGO and lighter products.

  The following cuts are mixed: hydrotreated N, MD (HDT effluent), hydrocracked VGO (M-HDK effluent), and 75% weight of the mixture is separated off to produce a P * a oil which is of high quality: without asphaltenes and low sulfur content (e.g. less than 0.3% wt or even less than 0.1%). The remaining 25% wt. Of the mixture is added to the hydroconversion effluent of the RHDC residues to form a second refined petroleum P * b which contains unconverted asphaltenes and is therefore a residual oil.

  Example 2 According to the Invention: The same oil P of the example 1 is pre-refined by carrying out the following operations: a) P is fractionated by atmospheric distillation and then under vacuum to produce 5 cuts: a n-cut of naphtha (and component lighter) representing 20% by weight of P, of which 18% naphtha and 2% lighter compounds; an MD cup of middle distillates representing 25% by weight of P; an IGO (or LVGO) cut of light vacuum distillate, rich in compounds boiling between 360 and 420 ° C., and representing 15% by weight of P; a HVGO heavy vacuum distillate cutter representing 20% by weight of P; - A vacuum residue cup VR representing 20% of P. On hydrotraite MD converts IGO to 20% conversion including 1% C4 - gas, 4% naphtha and 15% of middle distillates by mild hydrocracking M-HDK, and converts HVGO to 30% conversion including 2% C4 - gas, 6% naphtha and 22% middle distillates, by mild hydrocracking M-HDK.

  Hydroconversion in RHDC bubbling bed is converted into the vacuum residue VR at 60% conversion to VGO and lighter products.

  A first mixture Ma is produced with the following cuts: 60% by weight of N, 40% by weight of hydrotreated MD (HDT effluent), and hydrotreated IGO, and 75% by weight of the Ma mixture is separated off to produce a Pa oil which is high quality: without asphaltenes and low sulfur content (eg less than 0.3% by weight or even less than 0.1%). Pa is an oil with relatively high gasoline potential and relatively low middle distillate potential: Ra = 1.209.

  A second Mb mixture is made with the following cuts: 40% by weight of N, 60% by weight of hydrotreated MD (HDT effluent), and hydrocracked HVGO, and 75% by weight of the Mb mixture is separated off to produce a Pb oil which is high quality: without asphaltenes and low sulfur content (eg less than 0.3% by weight or even less than 0.1%). Pb is an oil with a relatively low gasoline potential and a relatively high average distillate potential: Rb = 0.7.

  The remaining 25% wt. Of Ma and Mb is added to the hydroconversion effluent of the HRCS residues to form a third refined petroleum Pc which contains unconverted asphaltenes and is therefore a residual oil.

  The Ra / Rb ratio is therefore 1.73. A refinery will typically be able to source Pc oil to satisfy its residual fuel market, and then estimate, based on Pc refining efficiencies, the relative need for naphtha, gasoline, and middle distillates. It then has two oils Pa and Pb, which it can choose the distribution, to adjust the balance (naphtha + gasoline) / middle distillates.

Claims (17)

  1. Process for the pre-refining of at least one crude oil P, with catalytic hydrogenation treatment of one or more cuts from P comprising: at least a first step F1 of PRE-DIST initial distillation fractionation to produce a first R1 residue and at least a first non-asphaltenic stream E1, - at least a second stage F2 fractionation of at least a portion of R1, vacuum distillation VAC-DIST and / or solvent deasphalting SDA, to produce at least a second non-asphaltenic stream E2, and an asphaltenic residue R2, at least one hydrotreatment step HDT and / or HDC hydroconversion and / or HDK hydrocracking of at least a portion of E2 to produce an effluent HE2, optionally an HRDC hydroconversion step of at least one asphaltenic fraction derived from R2, in which the fractionation and / or catalytic hydrogenation treatment steps of the process are determined so that at least two of the non-asphaltenic effluents produced from P have different R ratios, with the following definition: R = (0.9 N + 0.5 VGO +) / (MD + 0, 1 VGO +), with: N = naphtha:% by weight cutting boiling between 30 C and 170 C; MD = middle distillates:% weight of the cup boiling above 170 C and not more than 20 360 C; VGO + =% weight of the fraction boiling above 360 C; the method further comprising the steps of: a) recomposing and producing from non-asphaltenic effluents produced from P, optionally hydrotreated and / or hydroconverted and / or hydrocracked, at least two non-asphaltenic oils Pa and Pb having R, ie Ra and Rb, which are different, b) at least one residual oil Pc comprising at least a majority of the asphaltenes of the asphaltenic residue R2 or at least residual asphaltenes after hydroconversion RHDC is produced if the process comprises such a step.   2. Method according to claim 1 wherein Pa and Pb are essentially formed from fractions from the group of following cuts from P, optionally hydrotreated and / or hydroconverted and / or hydrocracked: naphtha N, middle distillates MD, intermediate gas oil IGO , LVGO light vacuum distillate, heavy HVGO or total VGO, DAO deasphalted oil.   3. Method according to one of claims 1 and 2 wherein 1.15 <Ra / Rb <4.   4. Method according to one of claims 1 to 3 wherein 0.8 <Ra <1.7 and 0.3 <Rb <10 1.0.   5. Method according to one of the preceding claims wherein Pc comprises the greater part at least of the effluent of a RHDC hydroconversion of R2 bubbling bed.   6. Method according to one of the preceding claims wherein R2 is asphalt AS obtained by deasphalting SDA solvent.   7. Process according to claim 6, in which AS is hydroconverted in a bubbling bed, to which is added a liquid diluent comprising at least 30% by weight of compounds boiling below 340.degree.   The process of claim 7 wherein the amount of diluent is from 4% to 40% by weight of AS.   9. The method of claim 6 wherein the untreated asphalt AS is directly mixed with one or more petroleum fractions to form the petroleum Pc, the vacuum residue then contains virgin asphaltenes in increased amount relative to the vacuum residue of the P oil The method of claim 9 wherein said petroleum fractions comprise at least one crude oil fraction P which is mixed with AS.   11. Method according to one of the preceding claims wherein Pa, Pb, and Pc are formed so that the percentage of compounds boiling between 360 C and 400 C with respect to the VGO fraction is lower for Pb than for P as well as for at least one of the oils Pa, Pc.   12. Method according to one of the preceding claims wherein Pa, Pb, and Pc, are three oils, final pre-refining products, each of these oils being intended to be used as an initial distillation feed of one or typically several oil refineries.   13. Method according to one of the preceding claims wherein is transported separately the greater part at least Pa and Pb by pipelines and oil boats for use as initial distillation charges of one or more oil refineries. .   14. Process according to one of the preceding claims, in which Pa, Pb and Pc each comprise at least 6% by weight of naphtha N, at least 10% by weight of middle distillates MD, and at least 10% by weight of vacuum distillate. VGO.   15. Non-asphaltenic reconstituted oil Pa, comprising at least 30% by weight of naphtha N, having a ratio R greater than or equal to 1.7 and a gasoline potential POTe of between 50 and 70, with POTe = 0.9 N + 0.5 VGO +.   16. Reconstituted petroleum according to claim 15, comprising between 30% and 50% by weight of naphtha N, having a ratio R between 1.75 and 2.5 and a gasoline potential POTe of between 55 and 70. 17. Reconstituted petroleum according to claim 16, comprising between 36% and 50% by weight of naphtha N, having a ratio R between 1.80 and 2.5 and a petrol potential POTe of between 58 and 70.