WO2011128519A2 - Process for the hydroconversion of petroleum feedstocks via slurry technology allowing the recovery of metals from the catalyst and feedstock using a leaching step - Google Patents

Abstract

A process for the hydroconversion of heavy petroleum feedstocks comprising a step of hydroconversion of the feedstock in at least one reactor containing a catalyst in a slurry and enabling the recovery of metals in the unconverted residual fraction, especially those used as catalysts. The process comprises a hydroconversion step, a gas/liquid separation step, a liquid/liquid extraction step, a milling step, a leaching step, a combustion step, a metal extraction step and a step of preparing catalytic solutions that are recycled to the hydroconversion step.

Description

 METHOD FOR HYDROCONVERSION OF PETROLEUM LOADS VIA SLURRY TECHNOLOGY FOR RECOVERING METALS FROM THE CATALYST AND THE LOAD USING A LEACHING STEP

The invention relates to a process for the hydroconversion of heavy petroleum feedstocks into lighter products, recoverable as fuels and / or raw materials for petrochemicals. More particularly, the invention relates to a process for hydroconversion of heavy petroleum feeds comprising a step of hydroconversion of the feedstock in at least one reactor containing a slurry catalyst and allowing the recovery of the metals in the unconverted residual fraction, in particular those used as catalysts, in order to valorize them in catalytic solutions and to recycle them upstream of the slurry conversion process. The method comprises a hydroconversion step, a gas / liquid separation step, a liquid-liquid extraction step, a grinding step, a leaching step, a burning step, a metal extraction step, and a step of catalytic solution (s) preparation step (s) which is / are recycled (s) in the hydroconversion stage.

The conversion of heavy oil loads into liquid products can be done by heat treatments or by hydrogenation treatments, also called hydroconversion. Current research is mainly focused on hydroconversion because heat treatments generally produce poor quality products and a significant amount of coke.

 The hydroconversion of heavy feeds involves the conversion of the feedstock in the presence of hydrogen and a catalyst. Commercialized processes use depending on the load, fixed bed technology, bubbling bed technology or slurry technology.

 The hydroconversion of heavy charges in fixed bed or bubbling bed is by supported catalysts comprising one or more transition metals (Mo, W, Ni, Co, Ru) on supports of silica / alumina or equivalent type.

For the conversion of heavy loads particularly charged to heteroatoms, metals and asphaltenes, fixed bed technology is generally limited because contaminants cause deactivation. fast catalyst thus requiring a renewal frequency of the catalyst bed too high and therefore too expensive. In order to be able to treat this type of charges, ebullated bed processes have been developed. However, the conversion level of ebullated bed technologies is generally limited to levels below 80% due to the catalytic system employed and the design of the unit.

 Hydroconversion technologies operating with slurry technology provide an attractive solution to the disadvantages encountered in the use of the fixed bed or bubbling bed. Indeed, the slurry technology makes it possible to treat heavy loads heavily contaminated with metals, asphaltenes and heteroatoms, while having conversion rates generally greater than 85%.

Slurry residue hydroconversion technologies utilize a dispersed catalyst in the form of very small particles, the size of which is less than 1 mm and preferably a few tens of microns or less (generally 0.001 to 100 μm). Due to this small size of the catalysts, the hydrogenation reactions are facilitated by a uniform distribution throughout the reaction zone and the coke formation is greatly reduced. The catalysts, or their precursors, are injected with the feed to be converted at the inlet of the reactors. The catalysts pass through the reactors with the feedstocks and the products being converted, and then are driven with the reaction products out of the reactors. They are found after separation into the heavy residual fraction, such as, for example, the unconverted vacuum residue. The catalysts used in slurry are generally sulfurized catalysts preferably containing at least one member selected from the group consisting of Mo, Fe, Ni, W, Co, V and / or Ru. Generally, molybdenum and tungsten show much more satisfactory performance than nickel, cobalt or ruthenium and even more than vanadium and iron (N. Panariti et al., Applied Catalysis A: General 204 (2000), 203). -213).

The hydroconversion technologies of commercialized heavy slurries are known. For example, EST technology licensed by ENI, VRSH technology licensed by Chevron-Lummus-Global, HDH and HDHPLUS technologies licensed by Intevep, UOP-licensed SRC-Uniflex technology, Headwaters-licensed (HC) 3 technology, etc.

Although the small size of the slurry catalysts makes it possible to obtain very high conversion rates, this size is problematic as regards the separation and recovery of the catalyst (s) after the hydroconversion reaction. The catalysts are found after separation in the heavy residual fraction, such as unconverted vacuum residue. In some processes, a portion of the vacuum residue containing the unconverted fraction and the catalysts is recycled directly to the hydroconversion reactor to increase conversion efficiency. However, these recycled catalysts generally have no activity or much reduced activity compared to fresh catalyst. In addition, the vacuum residue is traditionally used as fuel for the production of heat, electricity and ash. These ashes contain metals and are generally dumped. In this case, the metals are not recovered.

 In addition, the deactivation of the catalysts requires regular replacement thus creating a demand for fresh catalysts. The heavy loads treated contain a high concentration of metals, mainly vanadium and nickel. These metals are largely removed from the charge by settling on the catalysts during the reaction. They are washed away by the catalyst particles leaving the reactor. Similarly, the deactivation of the catalysts is accentuated by the formation of coke, in particular from the high concentration of asphaltenes contained in these feeds.

The continuous renewal of the catalytic phase finely dispersed in the reaction zone allows the contact of the hydrogen dissolved in the liquid phase to hydrogenate and hydrotrate the injected heavy load. In order to ensure a high level of conversion and maximum hydrotreatment of the load, the amount of catalytic solution to be injected is quite high which represents relatively high operating costs on a commercial scale. Thus, slurry hydroconversion processes are generally consuming a large amount of catalysts, in particular molybdenum, which has the most active catalyst, but also the most expensive. The costs of fresh catalysts, catalyst separation and metal recovery have a major impact on the profitability of such processes. The selective recovery of molybdenum and its recycling as a catalyst are two essential elements for the industrial valorization of slurry processes. This recovery is also accompanied by those of other metals such as nickel (the one injected and the one recovered in the charge) and the vanadium recovered in the charge whose contents are comparable to that of molybdenum and which can be resold for metallurgical applications.

 Apart from these economic aspects, the recovery of metals is also necessary for environmental reasons. In fact, ashes from the combustion of the residual fraction have been classified in many countries as hazardous waste because the metals contained in the ashes disposed of in dump sites present a danger for the water table.

 There is therefore a real need for recovery and recycling of metals from catalysts and the heavy load of slurry hydroconversion process.

Prior art

 The metal recovery processes of the slurry processes are. known in the state of the art.

Thus, patent US4592827 describes a slurry hydroconversion process for heavy charges in the presence of a soluble metal compound and water comprising, after the hydroconversion reaction, a separation step, a step of deasphalting the fraction. vacuum residue with C5 to C8 hydrocarbons and a step of gasification of the asphaltenes producing hydrogen and ash containing the catalyst. This The catalyst is then subjected to metal extraction steps, the metals are recycled in the process.

 US2009 / 0159505 discloses a slurry hydroconversion process for heavy loads and the recovery of metals contained in the catalyst by employing membrane filtration in the presence of a solvent. After the filtration step, an optional washing step employing surfactants is disclosed.

US Pat. No. 4,548,700 discloses a heavy duty slurry hydroconversion process comprising, after the hydroconversion reaction, a step of separation of the gaseous fraction, a distillation step, a washing of the atmospheric residue (650 ° F ⁺ = 343 °). C ⁺ ) to toluene at atmospheric pressure and ambient temperature and a step of combustion or gasification of the solid fraction at temperatures between 427-1093 ° C (800-2000 ° F) to obtain ash containing the metals. The metals V and Mo are recovered by an extraction step with oxalic acid and then recycled in the process.

 US Pat. No. 6,601,937 describes a heavy-duty slurry hydroconversion process comprising, after the hydroconversion reaction, a separation step in a high-pressure, low-temperature separator for separating a very light fraction, a deasphalting step of any the residual fraction using paraffinic C3 to C5 solvents at room temperature, a coking step (427-649 ° C, without air) and / or a combustion step below 649 ° C to produce ash containing the catalyst. This catalyst may subsequently be subjected to metal extraction steps and recycled to the process.

Object of the invention

The specificity of slurry processes being to have a finely dispersed and unsupported catalyst on a mineral phase makes the recovery of metals much more complex than those of catalysts supported refining traditionally used. The challenge for industrial development of hydroconversion processes using slurry technology is the need to recover and recycle metals from catalysts.

 The present invention aims to improve the methods of hydroconversion of heavy loads by slurry technology known by allowing the valuation of a residual unconverted fraction resulting from the conversion to slurry fraction highly concentrated in metals and heteroelements and ultimately including the recovery of said metals in said unconverted fraction and the production of catalytic precursors for recycling upstream of the conversion process in slurry mode. The method comprises a hydroconversion step, a gas / liquid separation step, a liquid / liquid extraction step, a grinding step, a leaching step, a burning step, a metal extracting step, and a step of catalytic solution (s) preparation step (s) which is / are recycled (s) in the hydroconversion stage.

The research work carried out by the applicant on the hydroconversion of heavy loads led him to discover that, surprisingly, this process comprises a separation making it possible to maximize the light fraction resulting from the hydroconversion reactor and to minimize the residual fraction. , coupled with a liquid / liquid extraction step using a paraffinic solvent and a leaching step allowing the concentration of metals and a moderate combustion step avoiding the sublimation of metals, made it possible to prepare the extraction of metals contained in the ash in such a way that very good recovery rates of recyclable metals in the process are possible. Indeed, the critical stages of this recovery are first the concentration of the metals on the carbon matrix (via the extraction followed by the leaching) then the formation of a mineral phase (via the moderate combustion) containing the metallic elements coming from the catalyst (Mo and Ni) but also the charge (Ni, V and Fe) devoid of carbon. An advantage of the method according to the invention is the recovery of an unconverted residual fraction highly concentrated in metals and heteroelements for the recovery of said metals and the production of catalytic precursors for recycling upstream of the conversion process in slurry mode.

 Another advantage is the optimization of the hydroconversion conversion by a gas / liquid separation after the hydroconversion operating under operating conditions close to those of the reactor and allowing the effective separation in a single step of a light fraction comprising the future fuel bases (gases, naphtha, light gas oil or even heavy diesel) of the unconverted residual fraction containing solids such as metals. The yield of the light fraction is thus maximized at the same time that the unconverted residual fraction is minimized thereby facilitating the reduced concentration of the metals thereafter. Maintaining the operating conditions during the separation also allows the economical integration of a subsequent treatment of hydrotreating and / or hydrocracking of the light fraction without the need for additional compressors.

 Another interest is the liquid / liquid extraction followed by a leaching step of the unconverted fraction containing the metals allowing extraction of insoluble (and therefore a concentration of metals) effective.

 Another advantage of the process is the combustion at moderate temperature to separate the organic phase of the inorganic phase containing the metals to facilitate the subsequent extraction of metals from the inorganic phase while avoiding vaporization and / or sublimation (and therefore loss) of metals during combustion.

 The method according to the invention therefore makes it possible to optimize the conversion of heavy charges into fuel base while allowing the recovery of metals with very good recovery rates.

detailed description

The invention relates to a process for hydroconversion of heavy petroleum slurry feeds for the recovery and recycling of metals in the unconverted residual fraction, especially those used as catalysts.

 More particularly, the invention relates to a process for hydroconversion of heavy petroleum feedstocks containing metals comprising:

 at. a step of hydroconversion of the feedstock in at least one reactor containing a slurry catalyst containing at least one metal, and optionally a solid additive,

 b. a step of separating the hydroconversion effluent without decompression into a so-called light fraction containing the compounds boiling at at most 500 ° C and a residual fraction, b '. optionally a fractionation step comprising a vacuum separation of said residual fraction as obtained in step b), and a concentrated metal vacuum residue is obtained,

 vs. a liquid / liquid extraction step with a saturated solvent of said residual fraction as obtained in step b) and / or said vacuum residue as obtained in step b ') making it possible to obtain a solid extract concentrated in metals and a raffinate, d. a step of grinding the concentrated solid metal extract from the liquid / liquid extraction step,

 e. a step of leaching the ground extract in the presence of water, a saturated solvent and a surfactant to obtain a solid extract and a leachate,

 f. a step of combustion in the presence of oxygen of said solid extract resulting from the leaching step making it possible to obtain concentrated ash in metals,

 boy Wut. a step of extracting the metals from the ashes obtained at the combustion stage,

h. a step of preparing metal solution (s) containing at least the metal of the catalyst which is / are recycled as a catalyst in the hydroconversion stage. hydroconversion

 The process according to the invention comprises a step of hydroconversion of the feedstock in at least one reactor containing a slurry catalyst and optionally a solid additive.

 Hydroconversion is understood to mean hydrogenation, hydrotreatment, hydrodesulfurization, hydrodenitrogenation, hydrodemetallization and hydrocracking reactions.

 The heavy loads concerned are petroleum hydrocarbon feedstocks such as petroleum residues, crude oils, crude heading oils, deasphalted oils, asphalts or deasphalting pitches, derivatives of petroleum conversion processes (for example: HCO, FCC slurry, GO heavy / VGO coking, visbreaking residue or similar thermal process, etc.), oil sands or their derivatives, oil shales or their derivatives, or mixtures of such fillers. More generally, herein will be grouped under the term "heavy load" hydrocarbon feeds containing at least 50 wt% of product distilling above 250 ° C and at least 25 wt% distilling above 350 ° C.

 The heavy charges concerned according to the invention contain metals, essentially V and / or Ni, at a rate of generally at least 50 ppm by weight and most often 100-2000 ppm by weight, at least 0.5% by weight of sulfur, and at least 1% by weight of asphaltenes (heptane asphaltenes), often more than 2% by weight or 5% by weight, of 25% by weight or more of asphaltenes attainable; they also contain condensed aromatic structures which may contain heteroelements refractory to conversion.

Preferably, the heavy feedstocks concerned are unconventional oils of the heavy crude type (API ° between 18 and 25 and a viscosity of between 10 and 100 cP), the extra heavy mills (API ° between 7 and 20 and viscosity between 100 and 10,000 cP) and oil sands (API between 7 and 12 ° API and viscosity included less than 10,000 cP) present in large quantities in the Athabasca region of Canada and Venezuela's Orinoco, where reserves are estimated at 1700 Gb and 1300 Gb, respectively. These unconventional oils are also characterized by high levels of residues under vacuum, asphaltenes and heteroelements (sulfur, nitrogen, oxygen, vanadium, nickel, etc.) which require conversion steps to commercial gasoline type products. specific diesel or heavy fuel oil.

The heavy charge is mixed with a hydrogen stream and a catalyst as dispersed as possible to obtain hydrogenating activity as evenly distributed as possible in the hydroconversion reaction zone. Preferably, a solid additive promoting the hydrodynamics of the reactor is also added. This mixture feeds the catalytic hydroconversion section into slurry. This section consists of a preheating furnace for the charge and hydrogen and a reaction section consisting of one or more reactors arranged in series and / or in parallel, according to the required capacity. In the case of series reactors, one or more separators may be present on the effluent at the head of each of the reactors. In the reaction section, hydrogen can feed one, several or all of the reactors in equal or different proportions. In the reaction section, the catalyst can feed one, several or all the reactors in equal or different proportions. The catalyst is kept in suspension in the reactor, flows from the bottom to the top of the reactor with the gas and the feedstock, and is evacuated with the effluent. Preferably, at least one (and preferably all) of the reactors is provided with an internal recirculation pump.

The operating conditions of the catalytic hydroconversion section in slurry are generally a pressure of 2 to 35 MPa, preferably 10 to 25 MPa, a hydrogen partial pressure ranging from 2 to 25 MPa. 35 MPa and preferably 10 to 25 MPa, a temperature between 300 ° C and 500 ° C, preferably 420 ° C to 480 ° C, a contact time of 0.1 h to 10 h with a preferred duration of 0.5h at 5 o'clock. These operating conditions coupled to the catalytic activity make it possible to obtain conversion rates per pass of the vacuum residue 500 ° C. ^{+ which} can range from 20 to 95%, preferably from 70 to 95%. The conversion rate mentioned above is defined as the mass fraction of organic compounds having a boiling point greater than 500 ° C at the inlet of the reaction section minus the mass fraction of organic compounds having a boiling point. greater than 500 ° C at the outlet of the reaction section, all divided by the mass fraction of organic compounds having a boiling point greater than 500 ° C at the inlet of the reaction section.

 The slurry catalyst is in dispersed form in the reaction medium. It can be formed in situ but it is preferable to prepare it outside the reactor and to inject it, generally continuously, with the charge. The catalyst promotes the hydrogenation of radicals from thermal cracking and reduces coke formation. When coke is formed, it is removed by the catalyst.

The slurry catalyst is a sulfurized catalyst preferably containing at least one member selected from the group consisting of Mo, Fe, Ni, W, Co, V, Ru. These catalysts are generally monometallic or bimetallic (by combining, for example, a non-noble group VIIIB element (Co, Ni, Fe) and a group VIB element (Mo, W)). NiMo, Mo or Fe catalysts are preferably used. The catalysts used may be heterogeneous solid powders (such as natural ores, iron sulphate, etc.), dispersed catalysts derived from water-soluble precursors. ("water soluble dispersed catalyst") such as phosphomolybdic acid, ammonium molybdate, or a mixture of Mo or Ni oxide with aqueous ammonia. Preferably, the catalysts used are derived from soluble precursors in an organic phase ("oil soluble dispersed catalyst"). The precursors are organometallic compounds such as the naphthenates of Mo, Co, Fe, or Ni or such as multi-carbonyl compounds of these metals, for example 2-ethyl hexanoates of Mo or Ni, acetylacetonates of Mo or Ni , C7-C12 fatty acid salts of Mo or W, etc. They can be used in the presence of a surfactant to improve the dispersion of metals, when the catalyst is bimetallic. The catalysts are in the form of dispersed particles, colloidal or otherwise depending on the nature of the catalyst. Such precursors and catalysts that can be used in the process according to the invention are widely described in the literature.

 In general, the catalysts are prepared before being injected into the feed. The preparation process is adapted according to the state in which the precursor is and of its nature. In all cases, the precursor is sulfided (ex-situ or in-situ) to form the catalyst dispersed in the feedstock.

For the preferred case of so-called oil-soluble catalysts, in a typical process, the precursor is mixed with a petroleum feedstock (which may be part of the feedstock to be treated, an external feedstock, a recycled feedstock, etc.). the mixture is optionally dried at least partially, then or simultaneously sulphurized by addition of a sulfur compound (H ₂ S preferred) and heated. The preparations of these catalysts are described in the prior art.

 The preferred solid additives are inorganic oxides such as alumina, silica, Al / Si mixed oxides, supported spent catalysts (for example, on alumina and / or silica) containing at least one group VIII element (such as Ni, Co) and / or at least one element of group VIB (such as

Mo, W). For example, the catalysts described in the application US2008 / 177124. Carbonaceous solids with a low hydrogen content (for example 4% hydrogen), possibly pretreated, can also be used. Mixtures of such additives can also be used. Their particle sizes are preferably less than 1 mm. The content of any solid additive present at the inlet of the reaction zone of the slurry hydroconversion process is between 0 and 10% by weight and preferably between 1 and 3% by weight, and the content of the catalytic solutions is between 0 and 10% by weight. % wt, preferably between 0 and 1 wt%.

The processes for hydroconversion of heavy loads by known slurry technology are EST of ENI operating at temperatures of the order of 400-420 ° C, under pressures of 10-16 MPa with a particular catalyst

(molybdenite); (HC) 3 from Headwaters operating at temperatures of the order of 400-450 ° C, at pressures of 10-15 MPa with pentacarbonyl

Fe or Mo 2-ethyl hexanoate, the catalyst being dispersed in the form of colloidal particles; HDH and HDHPLUS licensed by Intevep / PDVSA operating at temperatures of 420-480 ° C, under pressures of 7-20

MPa, using a dispersed metal catalyst; Chevron CASH using a Mo or W sulfide catalyst prepared by aqueous means; SRC-Uniflex

UOP operating at temperatures of the order of 430-480 ° C, under pressures of 10-15 MPa; VCC developed by Veba and belonging to BP operating at temperatures of the order of 400-480 ° C, at pressures of 15-30 MPa, using an iron-based catalyst; Microcat of Exxonmobil; etc ..

 All these slurry processes can be used in the process according to the invention.

Separation

 The totality of the effluent resulting from the hydroconversion is directed towards a separation section, generally in a high pressure and high temperature separator (HPHT), which makes it possible to separate a fraction converted into a gaseous state, called a light fraction, and a liquid unconverted fraction containing solids, said residual fraction. This separation section is preferably carried out under operating conditions close to those of the reactor, which are in general a pressure of 2 to 35 MPa with a preferred pressure of 10 to 25 MPa, a hydrogen partial pressure ranging from 2 to 35 MPa. and preferentially from 10 to 25 MPa and a temperature of between

300 ° C and 500 ° C, preferably 380 ° C to 460 ° C. The residence time of the effluent in this separation section is 0.5 to 60 minutes and preferably 1 to 5 minutes. The light fraction contains, for the most part, the compounds boiling at at most 300 ° C., or even at most 400 ° C. or 500 ° C .; they correspond to the compounds present in gases, naphtha, light diesel or even heavy diesel. It is indicated that the cut contains very predominantly these compounds, because the separation is not made according to a precise cutting point, it is more like a flash. If we had to speak in terms cutting point, we could say that it is between 200 ° and 400 ° or 450 ° C.

The valorization of the light fraction is not the subject of the present invention and these methods are well known to those skilled in the art. The light fraction obtained after the separation can undergo at least one hydrotreatment and / or hydrocracking step, the objective being to bring the different cuts to the specifications (sulfur content, smoke point, cetane, aromatic content, etc.). The light fraction may also be mixed with another feed before being directed to a hydrotreatment and / or hydrocracking section. An external cut generally coming from another process existing in the refinery or possibly outside the refinery can be brought before the hydrotreatment and / or the hydrocracking, advantageously the external cut is for example the VGO resulting from the fractionation of the crude oil ( VGO straight-run), VGO from a conversion, a LCO (light cycle oil) or an HCO (heavy cycle oil) from FCC.

 In general, hydrotreatment and / or hydrocracking after hydroconversion can be done conventionally via a conventional intermediate separation section (with decompression) using, for example, after the high-pressure high-temperature separator, a high separator. low temperature pressure and / or atmospheric distillation and / or vacuum distillation. Preferably, the hydrotreatment and / or hydrocracking section is directly integrated into the hydroconversion section without intermediate decompression. In this case, the light fraction is sent directly, without additional separation and decompression steps to the hydrotreatment and / or hydrocracking section. This last embodiment makes it possible to optimize pressure and temperature conditions, avoids additional compressors and thus minimizes the costs of additional equipment.

The residual fraction resulting from the separation (for example by the HPHT separator) and containing the metals and a fraction of particles Solids used as a possible additive and / or formed during the reaction can be directed to a fractionation step. This fractionation is optional and comprises a vacuum separation, for example one or more flash flasks and / or, preferably, a vacuum distillation, making it possible to concentrate a metal-rich vacuum residue at the bottom of the flask or column. recover at the head of the column one or more effluents. Preferably, the residual fraction resulting from the decompression-free separation step is fractionated by vacuum distillation into at least one vacuum distillate fraction and a vacuum residue fraction, at least a portion and preferably all of said fraction residue under vacuum being sent to the liquid-liquid extraction step, at least a portion and preferably all of said vacuum distillate fraction being preferably subjected to at least one hydrotreatment and / or hydrocracking step.

 The liquid effluent (s) of the vacuum distillate fraction thus produced is (are) usually directed to a small extent to the slurry hydroconversion unit where they can be directly recycled. in the reaction zone or then it (s) can (wind) be used for the preparation of catalytic precursors before injection into the load. Another part of the effluent (s) is directed towards the hydrotreating and / or hydrocracking section, optionally mixed with other fillers, for example the light fraction derived from the HPHT separator or a vacuum distillate originating from of another unit, in equal or different proportions depending on the quality of the products obtained. The objective of the vacuum distillation is to increase the efficiency of the liquid effluents for a subsequent treatment of hydrotreatment and / or hydrocracking and thus to increase the yield of fuel bases. At the same time, the amount of the residual fraction containing the metals is reduced, thus facilitating the concentration of the metals.

Liquid-liquid extraction

The residual fraction resulting from the no-decompression separation (via the HPHT separator for example) and / or the vacuum residue fraction of the separation under vacuum (for example withdrawn at the bottom of vacuum distillation) are then directed to a liquid / liquid type extraction step. This step has the objective of concentrating the metals in the effluent to be subsequently treated by lixiviation and combustion, by reducing its quantity, and to maximize the liquid effluent yield for the hydrotreatment and / or hydrocracking treatment.

 The liquid / liquid extraction can be done in a mixer-settler or in an extraction column. The operating conditions are in general a solvent / filler ratio of 1/1 to 10/1, preferably of 2/1 to 7/1, a temperature profile of between 50 ° C. and 300 ° C., preferably of 120 ° C. and 250 ° C depending on the solvent. The solvent used preferably has a saturated character. It may be a paraffinic solvent, such as butane, pentane, hexane or heptane, mixed or not in equal proportions or different. The solvent may also be a light naphtha (C6 to C10) saturated, mixed or not in proportions equal to or different from the paraffinic solvents mentioned above. After contact of the solvent with the residual fraction and / or the residue under vacuum, two phases are formed, the solid extract consisting of the parts of the residue which is not soluble in the solvent (and concentrated in metals) and the raffinate consisting of the solvent and parts of the soluble residue. The solvent is distilled off from the soluble parts and recycled internally to the liquid / liquid extraction process; the management of the solvent being known to those skilled in the art.

 At least a part of the soluble fraction after distillation of the solvent, and preferably all, is advantageously mixed with the heavy hydrocarbon feedstock upstream of the slurry hydroconversion section. A smaller portion may also be mixed with the light fraction of the no decompression separation for further hydrotreatment and / or hydrocracking treatment.

The solid extract from the liquid-liquid extraction is sent to a grinding stage. Grinding

 The solid extract resulting from the liquid-liquid extraction is sent to a mill which makes it possible to reach the desired granulometry for the purpose of leaching. The grinding step makes it possible to obtain a solid effluent with a particle size of less than 6 mm, preferably less than 4 mm. The milled solid is directed to a leach stage.

leaching

 The milled solid is directed to a leaching type extraction step. This step has the objective of concentrating the metals back into the solid to be subsequently treated by combustion, by reducing its quantity, and to maximize the liquid effluent yield for the hydrotreatment and / or hydrocracking treatment.

 The leaching step comprises several substeps, in particular: a) a step for preparing an emulsion comprising the ground extract of the grinding stage, water, a surfactant and a saturated solvent, b) a step of maturation of the emulsion at a temperature between 20 and 120 ° C, c) a decantation step by maintaining the temperature to obtain a solid extract and a leachate.

The leaching step uses a mixture of water, a surfactant and a solvent. The first step is to prepare an emulsion. The ground solid is mixed with water and a surfactant. The water / charge ratio is between 0.5 / 1 and 5/1, preferably between 1/1 and 2/1. The surfactant is used in concentrations ranging from 0.05 wt% to 2 wt% relative to water and preferably from 0.1 wt% to 1 wt%. A solvent is added to the solution previously prepared. The solvent / filler ratio is between 2/1 and 6/1, preferably between 3/1 and 4/1.

 The role of the surfactant is to stabilize the dispersion of the extract in the water initially and then stabilize the solvent emulsion in water. Thus, the surfactant must be sufficiently hydrophilic. The surfactant in the present invention may be anionic, cationic or nonionic surfactant.

 It is conceivable to use all the conventional anionic surfactants, such that the anionic function is:

 carboxylates: for example the soaps of alkali metals, alkyl or alkyl ether carboxylates (for example tall oils or derived acids), N-acylamino acids, N-acylglutamates, N-acylpolypeptides,

sulphonates, for example alkylbenzenesulphonates, paraffin sulphonates, olefin sulphonates, petroleum sulphonates, lignosulphonates, sulphosuccinic derivatives, polynaphthylmethanesulphonates, alkyltaurides,

 sulphates: for example alkyl sulphates, alkyl ether sulphates,

 phosphate: for example monoalkyl phosphates, dialkyl phosphates,

 phosphonate.

 As cationic surfactants, mention may be made of alkylamine salts or else quaternary ammonium salts whose nitrogen:

 contains a fatty chain (for example alkyltrimethyl or triethylammonium derivatives, alkyldimethyl or benzylammonium derivatives), contains two fatty chains,

is part of a heterocycle (for example, pyridinium, imidazolinium, quinolinium, piperidinium, morpholinium derivatives). As nonionic surfactants, it is conceivable to use all conventional and known nonionic surfactants. The nonionic surfactant products can be classified according to the mode of bonding between the hydrophobic part and the hydrophilic part of the molecule. This binding mode may be an ether bridge, an ester bridge, an amide bridge or the like. We can use : nonionic derivatives with ether bridge: for example oxyethylated fatty alcohols, oxyethylated alkylphenols, oxyethyloxypropylated products, glucose ethers,

 ester-bridge nonionic surfactants: for example, glycerol esters, polyethylene glycol esters, sorbitan esters, sugar esters.

 amide bonded nonionic surfactants: for example diethanolamides,

 the other surfactants, for example ethoxylated fatty amines,

 Mention may also be made of ethoxylated alkanolamides, ethoxylated amines or block copolymers of ethylene oxide or of propylene oxide. It is also possible to use a mixture of different surfactants.

 Preferably, the surfactant used in the present invention is a mixture of tall oil fatty acid and sodium hydroxide.

The solvent used is preferably a saturated solvent. It may be a paraffinic solvent, such as hexane or heptane, mixed or not in equal or different proportions. The solvent may also be a light naphtha (C6 to C10) saturated, mixed or not in proportions equal to or different from the paraffinic solvents mentioned above. Heptane will preferably be used. The solvent used in the leaching step may be identical to the solvent used in the liquid-liquid extraction step and preferably selected from the group consisting of hexane, heptane, a light naphtha (C6 to C10) saturated, mixed or not and in equal proportions or different, to facilitate the operation and optimize the process.

The emulsion comprising the milled filler, water, the surfactant and the paraffinic solvent is brought to a temperature of between 20 ° C. and 120 ° C., preferably between 60 ° C. and 70 ° C. and mixed for a period of time. between 15 minutes and 3 hours. The mixture is then directed to a decantation step by maintaining the temperature to separate a strongly concentrated solid extract in the bottom of the settling tank and a leachate which is a light hydrocarbon phase containing the solvent at the head of the settling. The operating conditions are in general a residence time of between 15 minutes and 30 hours. The leachate is sent to a separation section, for example of flash type, in order to recycle the solvent upstream of the leaching section and / or to the liquid-liquid extraction unit. The nonvolatilized fraction of the leachate can then be mixed with the hydrocarbon feedstock upstream of the slurry hydroconversion section, or even mixed in small amounts with the effluent upstream of the hydrotreating and / or hydrocracking section. The highly concentrated leaching extract of metals is directed to a moderate combustion stage.

 The combination of liquid / liquid extraction and leaching minimizes the residual fraction to be treated and thus concentrates the metals. The combination of the liquid / liquid extraction and leaching steps lead to a lower final residue yield for combustion compared to a double paraffinic solvent deasphalting, for example. The level of extraction by leaching is thus higher than that obtained by double deasphalting.

Combustion

The extract from leaching is highly concentrated in metals. This extract is directed to a moderate temperature combustion step. Indeed, before metals can be recovered by conventional metal mining methods, a preliminary step is necessary to separate the organic phase from the inorganic phase containing the metals. Thus, the objective of the combustion step is to obtain ash containing easily recoverable metals in the subsequent metal recovery units, by burning the organic phase or carbon phase of the extract at a temperature and a pressure which limit the vaporization and / or sublimation of metals, especially that of molybdenum (sublimation temperature of about 700 ° C for M0O ₃ ). Thus, the step of reducing the organic phase consists of a combustion at moderate temperature in order to concentrate the metals, without significant loss by vaporization and / or sublimation towards the fumes, in a mineral phase which may contain a proportion of organic phase ranging from 0 to 100 wt%, preferably 0 wt% to 40 wt%. The operating conditions of this combustion are in general a pressure of from 0.1 to 1 MPa, preferably from 0.1 to 0.5 MPa, a temperature of 200 to 700 ° C., preferably of 400 to 550 ° C. The combustion is done in the presence of oxygen.

 The gaseous effluent resulting from the combustion requires purification steps in order to reduce the emission of sulfur and nitrogen compounds into the atmosphere. The processes conventionally used by those skilled in the field of air treatment are carried out under the operating conditions necessary to meet the standards in force in the country of operation of such a hydrocarbon feedstock treatment. .

 The solid resulting from the combustion is a mineral phase containing all, or almost all, the metal elements contained in the extract, in the form of ash.

 Direct treatment of the leach extract by a metal extraction method as described below without combustion shows an insufficient metal recovery rate.

Metal recovery

Ashes from combustion are sent to a metal extraction step in which the metals are separated from each other in one or more substeps. This recovery of the metals is necessary because the simple recycling of the ashes in the hydroconversion stage shows a very weak catalytic activity. In general, the metal extraction step makes it possible to obtain several effluents, each effluent containing a specific metal, for example Mo, Ni or V, generally in salt or oxide form. Each effluent containing a catalyst metal is directed to a step of preparing an aqueous or organic solution based on the metal identical to the catalyst or its precursor, used in the hyd conversion step. The effluent containing a metal from the feed being non-recoverable as a catalyst (such as vanadium for example) can be recovered outside the process.

The operating conditions, fluids and / or extraction methods used for the various metals are considered to be known to those skilled in the art and already used industrially, as for example described in Marafi et al., Resources, Conservation and Recycling. 53 (2008) 1-26, US4432949, US4514369, US4544533, US4670229 or US2007 / 0025899. The various known metal extraction routes generally include leaching by acidic and / or basic solutions, ammonia or ammonia salts, bioleaching by microorganisms, low temperature heat treatment ( roasting) by sodium or potassium salts, chlorination or the recovery of metals electrolytically. Acid leaching may be by inorganic acids (HCl, H ₂ SO 4, HNO ₃ ) or organic acids (oxalic acid, lactic acid, citric acid, glycolic acid, phthalic acid, malonic acid, succinic acid, salicylic acid, tartaric acid ...). For basic leaching, ammonia, salts of ammonia, sodium hydroxide or Na ₂ CO ₃ are generally used. In both cases, oxidizing agents (H2O2, Fe (NO3) 3, ΑΙ (Ν03) 3 ·.) May be present to facilitate extraction. Once the metals in solution, they can be isolated by selective precipitation (at different pH and / or with different agents) and / or by extraction agents (oximes, beta-diketone ...).

 Preferably, the metal extraction step according to the invention comprises leaching with at least one acidic and / or basic solution.

Preparation of catalytic solution (s)

The metals recovered after the extraction step are generally in the form of salt or oxide. The preparation of the catalytic solutions for producing the organic or aqueous solutions is known to those skilled in the art and has been described in the hydroconversion part. The preparation of catalytic solutions concerns especially molybdenum and nickel metals, vanadium being generally valorized as vanadium pentoxide, or in combination with iron, for the production of ferrovanadium, outside the process.

 The recovered metal recovery rate as a catalyst for the slurry or vanadium hydroconversion process is at least 50 wt%, preferably at least 65 wt% and more generally 70 wt%.

Description of figures

 The following figures show advantageous embodiments according to the invention. The installation and the method according to the invention are essentially described. We will not repeat the operating conditions described above.

 Figure 1 shows a process of hydroconversion of heavy oil loads incorporating a slurry technology without recovery of metals.

 FIG. 2 describes a process for hydroconversion of heavy petroleum feedstocks according to the invention.

 Figure 3 describes the different substeps of leaching.

In FIG. 1, charge 1 feeds the catalytic hydroconversion section in slurry A. This slurry catalytic hydroconversion section consists of a preheating furnace for charge 1 and hydrogen 2 and a reaction section. consisting of one or more reactors arranged in series and / or in parallel, according to the required capacity. The catalyst 4 or its precursor is also injected, as well as the optional additive 3. The catalyst 4 is kept in suspension in the reactor, flows from the bottom to the top of the reactor with the feedstock, and is evacuated with the effluent. The effluent 5 resulting from the hydroconversion is directed to a high-pressure and high-temperature separation section B which makes it possible to separate a fraction converted into the gaseous state 6, called the light fraction, and a residual unconverted liquid / solid fraction. 8. The light fraction 6 can be directed to a hydrotreatment and / or hydrocracking section C. An external cut 7 generally coming from another process existing in the refinery or possibly out of the refinery can be brought before hyd reprocessing and / or hydrocracking. The unconverted residual fraction 8 containing the catalyst and a solid particle fraction optionally used as an additive and / or formed during the reaction is directed to a fractionation step D. Fractionation step D is preferably vacuum distillation. making it possible to concentrate at the bottom of the column the metal-rich vacuum residue and to recover at the top of the column one or more effluents 9. In this scheme for upgrading a heavy load by a hydroconversion process in slurry used traditionally, the residue The metal-rich vacuum is used as a very high-viscosity fuel or as a solid fuel after pelleting, for example to produce heat and electricity on site or outside or as fuel in a cement plant. Metals are, a priori, not recovered. The effluent (s) 9 thus produced will (are) usually be directed via line 31 to a small extent to the A slurry hydroconversion unit where they can be directly recycled to the reaction zone or else (s) can (wind) be used for the preparation of catalytic precursors before injection in the feedstock 1 and for the other part to the hydrotreating and / or hydrocracking unit C via the line 30 mixed with the effluents 6 and or 7 in equal or different proportions depending on the quality of the products obtained.

In FIG. 2, the steps (and reference marks) for hydroconversion, HPHT separation, hydrotreatment and / or hydrocracking and vacuum distillation are identical to FIG. vacuum distillation D is directed to a liquid / liquid type extraction step E to concentrate the effluent 10. This extraction step E is carried out using a solvent 11 of saturated nature. The raffinate 12 leaving the extraction unit, after evaporation of the solvent, is preferably mixed via line 33 with the hydrocarbon feedstock 1 upstream of the hydroconversion section in slurry A, or mixed via line 32 with the effluent 6 and / or 7 upstream of the hydrotreatment and / or hydrocracking section C. The solid extract 13 strongly The metal concentrate is directed to a milling step F. This milling step F provides a milled solid which is subsequently directed to a unit leaching extraction step G to again concentrate the metals. This leaching step G is in several stages described below (FIG. 3). The first step is to make a mixture of the ground solid 14 with water additive of a surfactant and a saturated solvent 16. This mixture is heated and mixed. The mixture is then directed to a decantation stage to separate a solid extract in bottom of decanter 18 and a leachate 17 containing the solvent 16 at the head of the settling. The leachate 17 is sent to a separation section, for example of the flash type, in order to recycle the solvent 16 upstream of the leaching section G and / or to the liquid-liquid extraction unit E. The nonvolatilized fraction leachate 17 can then be mixed with the hydrocarbon feedstock 1 upstream of the slurry hydrocracking section A via the line 35 or even mixed in small quantities with the effluent 6 and / or 7 upstream of the hydrocracking section C via line 34. The solid extract 18 strongly concentrated in metals is directed to a step of reducing the organic phase by a moderate temperature combustion H to very strongly concentrate the metals, without significant loss by vaporization and / or sublimation to the fumes. The gaseous effluent from combustion 19 requires purification steps (not shown) to reduce the emission of sulfur and nitrogen compounds into the atmosphere. The product 20 resulting from the combustion H is a mineral phase containing all, or almost all, the metal elements contained in the extract 18, in the form of ash. The product described below is sent to a metal extraction step I in which the metals are separated from each other in one or more sub-steps. The effluent 21 from extraction I is composed of a molybdenum type metal in the form of salt or oxide. This effluent 21 is then directed to a preparation step J of an organic or aqueous solution based on molybdenum 23 identical to the catalyst 4 or its precursor recycled partially or totally in the hydroconversion step in slurry A via the line 40. The effluent 22 from extraction I is composed of a nickel-type metal under form of salt or oxide. This effluent 22 is then directed to a preparation step K of an organic or aqueous nickel-based solution 24 identical to the catalyst 4 or its precursor recycled partially or wholly in the hydroconversion step in slurry A via the line 41. The effluent from extraction I is composed of a vanadium type metal in salt or oxide form. This effluent can be recovered for example as vanadium pentoxide, or in combination with iron, for the production of ferrovanadium.

 Figure 3 describes the different stages of leaching. The ground solid 14 is mixed with water with a surfactant additive 15. A saturated solvent 16 is added to the previously prepared solution to form an emulsion in step G1. The mixture thus constituted 101 of the crushed feedstock 14, the additivated water 15 and the paraffinic solvent 16 is brought to a temperature of between 20 ° C. and 120 ° C., preferably between 60 ° C. and 70 ° C., and mixed for a period of time. duration between 15 minutes and 3 hours in the maturation stage G2. The mixture 102 is then directed, by maintaining the temperature, to a decantation step G3 to separate a solid extract in bottom of decanter 18 and the leachate 17 which is a light hydrocarbon phase containing the solvent 16 at the head of the settling. The leachate 17 is sent to a separation section, for example flash type (not shown), in order to recycle the solvent 16 upstream of the leaching section G and / or to the liquid-liquid extraction unit E. The nonvolatilized fraction of the leachate 17 can then be mixed with the hydrocarbon feedstock 1 upstream of the slurry hydrocracking section A, or even mixed in small quantities with the effluent 6 and / or 7 upstream of the hydrotreatment section and or hydrocracking C. The extract 18 is directed to a combustion step.

In the preferred case of a slurry hydroconversion using molybdenum and nickel-based catalyst, the hydroconversion uses a finely dispersed catalyst of nickel and molybdenum type with a concentration of 160 ppm by weight and 600 ppm by weight respectively. 'hydrogen. Considering that the industrial unit has a capacity of 50,000 barrels per day and a utilization rate of 90% per year, the amount of nickel and molybdenum consumed per year is therefore 0.4 and 1.6 kt / year respectively. Considering a cost of nickel of $ 25k / t and molybdenum of $ 60k / t, representative of average costs observed on the metal market over the last 5 years, the operating cost is $ 100 million per year.

 The process according to the invention makes it possible to recover a large part of the metals, nickel and molybdenum, present in the unconverted fraction of the effluent resulting from hydroconversion into slurry. The recovered metal recovery rate as a catalyst for the slurry hydroconversion process is at least 50 wt%, preferably at least 65 wt%, and more generally 70 wt%. This recycling of metals can therefore reduce the operating cost from $ 100 million a year to $ 30 million a year. The saving thus achieved is 70 million dollars makes it possible initially to pay the additional investments necessary for the recovery of these metals. On the other hand, the vanadium present in the heavy load at 400 ppm wt can be valorized as ferrovanadium. Considering a recovery rate of at least 50% by weight, preferably at least 65% by weight, and more generally 70% by weight, the sale of vanadium is estimated, considering an observed average cost of 40 k $ / t on the metal market over the past 5 years, at $ 12 million a year. This sale will also make it possible in the first time to pay the additional investments necessary for the recovery of these metals.

 The recovery of these metals in the unconverted residual fraction reduces the overall quantity of nickel and molybdenum used and thus reduces the environmental impact of the slurry hydroconversion process. Considering a recovery of 70% by weight of the metals present at the inlet of the reaction zone, the amount of additional catalyst is reduced to 0.1 t / year for nickel and 0.5 t / year for molybdenum compared to 0.4 t / year and 1.6 t / year without recycle.

Claims

 A process for hydroconversion of heavy petroleum feedstocks containing metals comprising:  at. a step of hydroconversion of the feedstock in at least one reactor containing a slurry catalyst containing at least one metal, and optionally a solid additive,  b. a step of separating the hydroconversion effluent without decompression into a so-called light fraction containing the compounds boiling at at most 500 ° C and a residual fraction, b '. optionally a fractionation step comprising a vacuum separation of said residual fraction as obtained in step b, and a concentrated metal vacuum residue is obtained,  vs. a liquid / liquid extraction step with a solvent of a saturated nature of said residual fraction as obtained in step b and / or of said vacuum residue as obtained in step b 'making it possible to obtain an extract solid concentrate of metals and a raffinate, d. a step of grinding the concentrated solid metal extract from the liquid / liquid extraction step,  e. a step of leaching the ground extract in the presence of water, a saturated solvent and a surfactant to obtain a solid extract and a leachate,  f. a step of combustion in the presence of oxygen of said solid extract resulting from the leaching step making it possible to obtain concentrated ash in metals,  boy Wut. a step of extracting the metals from the ashes obtained at the combustion stage, h. a step of preparing metal solution (s) containing at least the metal of the catalyst which is / are recycled as a catalyst in the hydroconversion stage. 2. Method according to claim 1 wherein said so-called light fraction from step b) separation without decompression is subjected to at least one hydrotreatment step and / or hydrocracking. 3. Method according to one of the preceding claims wherein said residual fraction from the decompression-free separation step is fractionated by vacuum distillation into at least one vacuum distillate fraction and a vacuum residue fraction, at least a portion and preferably all of said vacuum residue fraction being sent to the liquid / liquid extraction step, at least a portion and preferably all of said vacuum distillate fraction being subjected to at least one hydrotreating step and / or or hydrocracking. 4. Method according to one of the preceding claims wherein the liquid / liquid extraction step is carried out at a temperature between 50 ° and 300 ° C, preferably between 120 and 250 ° C. 5. Method according to one of the preceding claims wherein the liquid / liquid extraction step is carried out with a solvent / filler ratio of 1/1 to 10/1, preferably 2/1 to 7/1. 6. Method according to one of the preceding claims wherein the particle size of said metal-concentrated solid extract from the liquid / liquid extraction step obtained by grinding is less than 6 mm, preferably less than 4 mm. 7. Method according to one of the preceding claims wherein the leaching step comprises: a. a step of preparing an emulsion comprising the ground extract of the grinding stage, said water, said surfactant and said saturated solvent, the water / filler ratio being between 0.5 / 1 and 5/1, preferably between 1/1 and 2/1, the solvent / filler ratio being between 2/1 and 6/1, preferably between 3/1 and 4/1, and the concentration of the surfactant being between 0.05 wt% and 2 wt%, preferably between 0.1 wt% and 1 wt%, relative to water, b. a step of maturation of said emulsion at a temperature between 20 ° and 120 ° C, preferably between 60 and 70 ° C, optionally for a period of between 5 minutes and 3 hours, c. a decantation step by maintaining the temperature, optionally for a period of between 15 minutes and 30 hours, to obtain a solid extract and a leachate. 8. Method according to one of the preceding claims wherein the saturated solvent used in the liquid / liquid extraction step and in the leaching step is identical and preferably selected from the group consisting of hexane, heptane, a light naphtha with a saturated nature, mixed or not and in equal or different proportions. 9. Method according to one of the preceding claims wherein the combustion step operates at a pressure of - 0.1 to 1 MPa, preferably from - 0.1 to 0.5 MPa and at a temperature of 200 to 700 ° C, preferably 400 at 550 ° C in the presence of air. 10. Method according to one of the preceding claims wherein the metal extraction step g) comprises leaching with at least one acidic solution and / or basic. 11. Method according to one of the preceding claims wherein the heavy oil load is a hydrocarbon feed containing at least 50% by weight of product distilling above 250 ° C and at least 25% by weight distilling above 350 ° C. and contains at least 50 ppmw of metals, at least 0.5 wt% of sulfur and at least 1 wt% of asphaltenes (asphaltenes to heptane). 12. Method according to one of the preceding claims wherein the heavy oil load is selected from petroleum residues, crude oils, crude head oils, deasphalted oils, deasphalting asphalts, derivatives of petroleum conversion processes, oil sands or their derivatives, oil shales or their derivatives, or mixtures of such fillers. 13. Method according to one of the preceding claims wherein the hydroconversion step operates at a pressure of 2 to 35 MPa, preferably 10 to 25 MPa, a hydrogen partial pressure of 2 to 35 MPa, preferably from 10 to 25 MPa, a temperature between 300 ° C and 500 ° C, preferably 420 ° C to 480 ° C and a contact time of 0.1 h to 10 h, preferably from 0.5h to 5 h. 14. Method according to one of the preceding claims wherein the slurry catalyst is a sulfurized catalyst containing at least one element selected from the group consisting of Mo, Fe, Ni, W, Co, V, Ru. 15. Method according to one of the preceding claims wherein the additive is selected from the group consisting of inorganic oxides, the supported catalysts supported containing at least one element of group VIII and / or at least one element of group VIB, the carbonaceous solids having a low hydrogen content, or mixtures of such additives, said additive having a particle size of less than 1 mm.