FR2974109A1 - BIOMASS HYDROCONVERSION PROCESS INCORPORATING A TECHNOLOGY USING A REACTOR COMPRISING A DISPERSED CATALYST - Google Patents

Abstract

The invention relates to a method for hydroconversion of biomass comprising a step hydroconversion of the feedstock in the presence of hydrogen in at least one reactor containing a dispersed catalyst, the biomass being pretreated beforehand comprising a roasting step.

Description

The invention relates to a method for hydroconversion of biomass for producing fuel bases and / or chemicals. More particularly, the invention relates to a method for hydroconversion of biomass with a technology using a reactor containing a dispersed catalyst, said biomass being pretreated beforehand comprising a roasting step. In recent years, there has been a renewed interest in incorporating products of renewable origin into the fuel and chemical sectors, in addition to or in substitution for products of fossil origin. One possible route is the conversion of lignocellulosic biomass into fuels. Biomass has an elemental composition rich in carbon and oxygen but relatively low in hydrogen. To produce fuel bases from biomass, therefore, it is generally necessary to lower the oxygen content and increase the hydrogen content and / or reduce the carbon content. Biomass also contains other heteroatoms (sulfur, nitrogen, etc.) and inorganic compounds of various natures (alkali, transition metals, halogen, etc.).

There are different methods of biomass conversion. A method of transforming biomass is gasification followed by the manufacture of a fuel from the synthesis gas. Another method of transformation is liquefaction such as, for example, rapid pyrolysis or hydrothermal conversion, with or without a catalyst, but without the addition of hydrogen. However, these processes lead to bio-oils still very rich in oxygen, which are thermally little or not stable and which have physico-chemical properties still far removed from those required for the final products and therefore require subsequent treatments. In addition, these purely thermal processes, in essence, have a very poor selectivity and these reactions can be accompanied by a large production of gas and solids.

Another potentially attractive solution is the hydroconversion of the biomass using a catalytic process in the presence of hydrogen and a solvent, preferably a hydrogen donor solvent. This route allows a significant direct incorporation of hydrogen and produces an organic liquid having a reduced oxygen content and a molar ratio H / C close to that of hydrocarbons. During the hydroconversion of the biomass, the reactions in the reactor (s) are deoxygenation reactions which decompose in reaction of decarbonylation (-CO), decarboxylation (-CO2) and hydrodeoxygenation (-H2O), reactions hydrodesulfurization (HDS), hydrodenitrogenation reactions (HDN), hydrogenation reactions of unsaturations and / or aromatic rings (HDoI, HDA), more generally all hydrotreatment reactions (HDT), reaction reactions hydrocracking (HCK) which leads to naphthenic ring opening or fractionation of paraffins into several smaller molecular weight fragments, thermal cracking reactions and polycondensation (coke formation) although these are not desired, water gas shift reactions: CO + H2O - CO2 + H2, and methanation reactions: CO + 3 H2 - + CH4 + H2O. All reactions using hydrogen can be based on molecular hydrogen as on hydrogen transfer reactions between the hydrogen donor solvent or the conversion products (since the donor solvent can come from certain families of recycled conversion products) and reagents.

The hydroconversion of the biomass can be carried out according to a bubbling bed technology or according to a technology in trained bed (also called "slurry" technology according to the English terminology).

Bubbling bed technologies use supported catalysts in the form of extrudates whose diameter is generally of the order of 1 mm or less than 1 mm. The catalysts remain inside the reactors and are not evacuated with the products. The conversion level of ebullated bed technologies is generally lower than for slurry technologies because of the catalytic system employed and the design of the unit. Slurry hydroconversion technologies use a dispersed catalyst (also called slurry catalyst afterwards) in the form of very small particles, the size of which is a few tens of microns or less (usually 0.001 to 100 dam). 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 in the heavy residual fraction. The thermal levels are very high which allows to obtain very high conversion levels. Although slurry processes offer higher conversion, these processes suffer from difficult operability and the conversion level is not as high as desired. The challenge for the industrial development of hydroconversion of biomass is to obtain biofuels with a high yield and acceptable qualities vis-à-vis the final specifications and / or constraints related to the later stages of transformation. The present invention relates to an improvement of biomass hydroconversion processes in slurry reactor. It has now been found that the use of a previously roasted biomass makes it possible to increase the conversion compared to the use of an unrefined biomass, while maintaining an excellent deoxygenation rate. Roasting can be defined as a pyrolysis at moderate temperature and controlled residence time because it is accompanied not only by drying, but also by partial destruction of the lignocellulosic material. The biomass particles after roasting are of a more spherical and less rough shape thus creating fewer agglomerates during the formation of the suspension. Roasting thus allows a more homogeneous fluidization in the slurry reactor. Likewise, this phenomenon facilitates the reaction ability of the filler in the medium and in particular in the reactor containing a dispersed catalyst. In fact, the roasted batch has a higher reactivity than the unroasted load (for example simply dried and / or milled) with respect to hydroconversion reactions in slurry thus leading to a higher conversion while maintaining an excellent rate of deoxygenation.

The improvement in reactivity can also be explained by the fact that the size of the biomass particles is particularly well suited to dispersed catalysts which themselves have a comparable size (better contact charge / catalyst), which creates a synergistic effect . The hydroconversion is all the easier as the water content of the biomass is low and in the form of divided particles, hence the interest of roasting operations. In addition, roasting causes chemical changes in the structure of the biomass. It loses its mechanical strength and elasticity, so it is much easier to grind. The grinding step which makes it possible to reach the desired particle size for the purpose of subsequent hydroconversion is facilitated by the roasting step, which makes it possible to reduce the energy consumption in comparison with grinding without prior roasting.

In addition, the roasted biomass is hydrophobic, and therefore remains dry and is insensitive to atmospheric moisture.

Biomass hydroconversion processes by slurry technology are known in the prior art. Thus, application US2008 / 0076945 describes a process for hydroconversion of lignin and cellulosic waste into fuel products in a bubbling bed reactor or in a slurry reactor. This document is silent on a possible pretreatment of biomass. The application US2009 / 0326285 describes a hydroconversion process of a renewable filler in one or more slurry reactors. The treated biomass can be in solid form (lignocellulosic biomass, cellulose, etc.), but it is preferably in liquid form (vegetable oils, pyrolysis oil, etc.). This document does not disclose precise pretreatment, but advocates a particle size of less than 50 mesh (297 μm) in the case of solid biomass. Pretreatment of the biomass by roasting is known in the prior art.

Thus, the application FR2904405 discloses the beneficial effect of a roasting of biomass for subsequent gasification to produce synthesis gas or "syngas", a raw material for the production of hydrocarbon cuts via Fischer-Tropsch synthesis. The publication "Proceedings of the 2009 AIChE Annual Meeting, Nashville, TN, Nov. 8-13, 2009, paper # 160229" by S. Mani describes the influence of roasting in thermochemical conversion processes of biomass, such as combustion, gasification and pyrolysis.

The present invention relates to an improvement of hydroconversion processes of biomass in a reactor containing a dispersed catalyst using as raw material roasted biomass. More particularly, the present invention relates to a biomass hydroconversion process chosen from lignocellulosic biomass and / or one or more lignocellulosic biomass constituents selected from the group consisting of cellulose, hemicellulose and lignin to produce fuel bases comprising : at. a step of preparing a suspension of the biomass particles in a solvent, b. then at least one hydroconversion step in the presence of hydrogen in at least one reactor containing a dispersed catalyst, and optionally a solid additive, c. and then at least one step of separating the effluent from the hydroconversion stage, characterized in that said biomass is subjected to a pre-treatment comprising a roasting step prior to the preparation of the suspension. According to the invention, a wide range of biomass can be treated with very high conversion levels, generally between 50 and 100% and preferably between 70 and 99%. The liquifiers obtained are of good quality with an oxygen content generally of between 0.1 and 5 wt.% Depending on the severity of the treatment. The deoxygenation of the charge is between 30 and 100%, preferably between 50 and 99%. This allows subsequent hydrotreatment and / or hydrocracking treatments under less stringent conditions with good yields to achieve the product qualities required by commercial specifications at lower processing and production cost. Thanks to the optimal preparation of the biomass by roasting, the operating conditions of the hydroconversion can be less severe than in the case of hydroconversion of unrefined biomass. This results not only in reduced reaction temperatures, but also in a reduction in catalyst consumption. Thus, the size of the recovery / recycling unit of the slurry catalyst (if this is necessary) as well as the operating cost can be reduced. The addition of new catalyst is further reduced. Similarly, it is possible to treat the biomass in co-treatment with other charges, allowing the recovery of loads often considered as waste. Detailed Description The Biomass Charge The biomass charge is selected from lignocellulosic biomass and / or one or more lignocellulosic biomass components selected from the group consisting of cellulose, hemicellulose and lignin. By lignocellulosic biomass is meant fillers rich in cellulose and / or hemi-cellulose and / or lignin. Cellulose and hemicellulose are essentially composed of sugar polymers (hexoses and pentoses). Lignin is essentially composed of crosslinked polymers having elementary units of the propyl methoxy phenol type. Only one of the constituents of this lignocellulosic biomass can be extracted for hydroconversion. This extract or the other remaining fraction may also constitute a filler that can be used in the invention, in particular lignin. The lignocellulosic raw material can be consists of wood or vegetable waste. Other non-limiting examples of lignocellulosic biomass material are farm residues (straw ...), logging residues (first thinning products), logging products, dedicated crops (coppice short rotation), food industry residues, household organic waste, wood processing facility waste, used wood for construction, paper, recycled or otherwise. Lignocellulosic biomass can also come from by-products of the paper industry such as Kraft lignin, or black liquors from pulp manufacturing. For simplicity, the term biomass subsequently used includes lignocellulosic biomass or one or more lignocellulosic biomass components selected from the group consisting of cellulose, hemicellulose and lignin.

The present invention also makes it possible to convert the biomass into co-treatment with other charges that are difficult to convert in fixed bed hydrotreating / hydroconversion processes. These charges may be of hydrocarbon (petroleum), non-petroleum or renewable nature. The hydrocarbon (petroleum) feedstocks concerned are fillers such as petroleum residues, crude oils, heavy or extra heavy crude oils, synthetic crudes, toasted crudes, deasphalted oils, deasphalting resins, deasphalting asphalts , derivatives of petroleum conversion processes (for example: light cycle oil (LCO), heavy cycle oil (HCO), fluid catalytic cracking residue (FCC), heavy gas oil / gas oil under coking vacuum, similar visbreaking residue or thermal process, etc.), oil sands or their derivatives, oil shales or their derivatives, or mixtures of such fillers. More generally, the term "hydrocarbonaceous feeds" will be used to include feedstocks containing at least 50% by weight of product distilling above 250.degree. C. and at least 25% by weight distilling above 350.degree. The non-petroleum feedstocks concerned are fillers such as coal or coal liquids obtained by hydroliquefaction, or hydrocarbon waste and / or industrial polymers, for example recycled polymers from used tires, used residues of polymers originating, for example, from vehicles. recycled automobiles, organic waste or household plastics, or mixtures of such loads. The feedstocks constituted by at least a portion of the Fischer Tropsch synthesis effluents produced from synthesis gas produced by gasification of petroleum, non-petroleum (coal, gas) or renewable (biomass) type feedstocks may also undergo co-treatment of conversion with biomass. Tars and residues that are not or difficult to recover from said gasification can also be used as a co-treatment feedstock.

All products or mixtures of products resulting from the thermochemical conversion of biomass, such as for example charcoal or pyrolysis oil of lignocellulosic biomass or algae, pyrolytic lignin (obtained by extraction of the pyrolysis oil ) or the products of the hydrothermal conversion of lignocellulosic biomass or algae in the presence of high water concentration and under high water pressure under subcritical or supercritical conditions of water and in the absence or in the presence of catalysts also present usable co-charges. Lignocellulosic biomass can also be treated with fillers from other renewable sources, for example oils and fats of vegetable or animal origin, or mixtures of such fillers, containing triglycerides and / or free fatty acids and / or esters. Vegetable oils can advantageously be crude or refined, wholly or in part, and derived from the following plants: rapeseed, sunflower, soybean, palm, palm kernel, olive, coconut, jatropha, this list not being limiting. Algae or fish oils are also relevant. Oils can also be produced from genetically modified organisms. Animal fats are advantageously chosen from lard or fats composed of residues from the food industry or from the catering industries.

It is also possible to use activated sludge from water treatment plants as a co-load or even algae (macroalgae and / or microalgae).

Roasting Prior to the preparation of the biomass / solvent slurry and its subsequent introduction into the hydroconversion reactor, the biomass is pretreated comprising a roasting step. The pretreatment of the biomass may also comprise, in addition to the roasting step, at least one of the following steps: a. a drying step 30 b. a grinding step.

Pretreatment of the charge can advantageously be done in different ways. The lignocellulosic biomass may be subjected to a drying step, then to a roasting step, then to a grinding step. The grinding stage may also take place after drying and may be supplemented by additional grinding after roasting. The drying and roasting steps can be done in a single step in the same equipment, followed by a grinding step. A coarse milling step (shredding) may precede all pretreatment steps. In the case of using wood as lignocellulosic raw material, the moisture content is around 50% at the time of cutting the tree in the forest. Natural air drying of tree trunks reduces moisture content to around 30-35%. Then, the trunks are crushed roughly into forest chips in the form of particles of a few centimeters (shredding). Advantageously, the biomass then undergoes a drying step which essentially eliminates the water contained in the biomass without causing changes in the chemical structure of the constituents. The drying step is carried out at a temperature below 250 ° C, preferably below 200 ° C, preferably for 15 to 120 minutes, to arrive at a water content of the biomass to be treated of about 1 at 10%.

Roasting can be defined as a pyrolysis at moderate temperature and controlled residence time because it is accompanied not only by drying, but also by partial destruction of the lignocellulosic material. The roasting step is carried out at a temperature between 200 ° C and 300 ° C, preferably between 225 ° C and 275 ° C, in the absence of air, preferably for 15 to 120 minutes, allowing to achieve a water content of the biomass to be treated of about 1 to 10%, preferably 1 to 5%. Lack of oxygen prevents combustion. On the other hand, roasting leads to a loss of mass due to the elimination of gases which generally amounts up to about 30% by weight, while the energy value is reduced by only about 10%. The roasted biomass therefore has a higher calorific value.

In the case of a single drying / roasting step in the same brand, the water content of the biomass to be treated can also reach 1 to 10%, preferably 1 to 5%. Known technologies for drying or roasting are for example the rotary furnace, the moving bed, the fluidized bed, the heated worm, the contact with metal balls providing heat. These technologies may optionally use a gas flowing at co or countercurrent such as nitrogen or any other gas inert under the conditions of the reaction. Other drying techniques are, for example, flocculation assisted by a chemical or physical adjuvant or by an electromagnetic field, decantation, centrifugation or gentle drying under conditions close to the point of vaporization of the water.

The biomass particles resulting from the drying and / or roasting stages are then advantageously sent to a mill which makes it possible to reach the desired particle size with a view to hydroconversion. Grinding prior to hydroconversion facilitates transport to the reaction zone and promotes gas / liquid / solid contacts. The grinding stage is considerably facilitated by the roasting stage which makes it possible to reduce the energy consumption compared to grinding without prior roasting.

In general, the pretreatment steps can be carried out in a decentralized mode near the biomass production or in a centralized mode directly feeding the hydroconversion. After pretreatment, biomass particles having a moisture content of 1 to 50%, preferably 1 to 35% and more preferably 1 to 10%, and a particle size of less than 600 μm, preferably less than 600 μm, are obtained. at 150 lim. Formation of the suspension Before introducing the biomass into the reactor containing a dispersed catalyst, the pretreated biomass, and in particular roasted biomass, is mixed with a solvent to prepare a biomass / solvent suspension. This biomass / solvent mixture is a suspension of biomass particles dispersed in said solvent, said suspension of fine solid particles in a liquid is also sometimes called "slurry" according to the English terminology (and should not be confused with the term reactor "in slurry" or "slurry catalyst" which denotes a reactor containing a catalyst dispersed in this text). To constitute the suspension, the size of the biomass particles is less than 5 mm, preferably less than 1 mm, preferably less than 650 μm and still more preferably less than 150 μm. The mass ratio solvent / biomass is generally from 0.1 to 3, preferably from 0.5 to 2. The solvent has a triple role: suspending the feedstock upstream of the reaction zone, thus allowing its transport to this region. last, then partial solubilization of the primary products of conversions and hydrogen transfer to these primary products to allow conversion to liquid by minimizing the amount of solid and gas forms in said reaction zone. This transfer of hydrogen thus presents an additional source of hydrogen for the essential need for hydrogen in the transformation of biomass into biofuels. The solvent may be any type of solvent known in the art for the preparation of a suspension. The solvent is preferably a hydrogen donor solvent comprising, for example, tetralin and / or naphtheno-aromatic molecules. Advantageously, the solvent comprises vacuum distillate, preferably vacuum gas oil (or Vacuum Gas Oil (VGO) according to the English terminology). It may also contain atmospheric distillate such as diesel or be derived from a solid / liquid or liquid / liquid extraction step and thus consist at least partially of compounds having boiling points similar to the compounds of the atmospheric distillates or vacuum distillates. It is also possible to use LCO (light cycle oil) or HCO (heavy cycle oil) from a fluidized catalytic cracking (FCC) or even anthracene oil.

In the case of a co-treatment with other charges, the solvent may also consist partially or completely of a liquid co-charge, such as, for example, vegetable oils or pyrolysis oils derived from a carbonaceous material ( biomass, coal, oil). According to a preferred variant, the solvent comes from a recycled fraction of the process. The effluent resulting from the hydroconversion stage is sent to a separating section separating the gases, a heavy fraction containing solid particles of catalyst and one or more liquid fractions without solids of the naphtha, kerosene, diesel and diesel fuel type. empty. Preferably, the liquid fraction (s) free from solids and having a distillation range in the range of 180 ° C to 550 ° C, preferably from 200 ° C to 550 ° C, is / are recycled (s), in part or in full, as a solvent to the suspension preparation step. This fraction preferably comprises vacuum distillate, and even more preferably vacuum gas oil. Part of the atmospheric distillates, such as diesel, can also be recycled, alone or as a mixture with the vacuum distillate fraction.

According to a preferred variant, the recycled fraction (s) undergoes / undergoes hydrotreatment prior to its / their recycling in the suspension. The objective of the hydrotreatment is to increase the content of the naphtheno-aromatics in the solvent and thus its role as hydrogen donor solvent in the hydroconversion. The operating conditions of the hydrotreatment are in general a pressure of 2 to 35 MPa, preferably 10 to 25 MPa, and a temperature of between 300 ° C. and 400 ° C., preferably 300 ° C. to 380 ° C. The hydrotreatment can be carried out in a bubbling bed or in a fixed bed. The conventional hydrotreatment catalysts contain at least one amorphous refractory oxide support (usually alumina) and at least one hydro-dehydrogenating element (generally at least one group VIB element (for example molybdenum and / or tungsten) and VIII non-noble (eg nickel and / or cobalt), and most often at least one group VIB element and at least one non-noble group VIII element). The amorphous refractory oxide support is chosen from the group formed by alumina, silica, silica-aluminas, magnesia, clays and mixtures of at least two of these minerals. Preferably, the hydrotreatment catalyst is a catalyst optionally comprising a doping element chosen from phosphorus, boron and silicon. Preferably, the catalysts used are based on cobalt-molybdenum or nickel-molybdenum on alumina.

The biomass / solvent suspension thus formed is subsequently introduced into the slurry hydroconversion reactor. The catalyst, as well as the optional additive can be added to the suspension before introduction into the slurry reactor.

Hydroconversion in slurry reactor

The biomass / solvent slurry is mixed with a stream of hydrogen and a catalyst as dispersed as possible to obtain a hydrogenating activity as evenly distributed as possible in the hydroconversion reaction zone. 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 entrained 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 to slurry are in general a pressure of 2 to 35 MPa, preferably 10 to 25 MPa, a hydrogen partial pressure ranging from 2 to 35 MPa and preferably from 10 to 25 MPa, temperature between 300 ° C and 450 ° C, preferably from 325 ° C to 420 ° C, a contact time of 0.1 h to 10 h with a preferred duration of 0.5 h to 5 h, at an hourly mass velocity between 0.1 and 5 h -1 and at a hydrogen / charge ratio of between 0.1 and 2 Nm 3 / kg and most often from about 0.1 to about 0.5 Nm 3 / kg. The operating conditions coupled with the fact that the biomass is roasted make it possible to obtain conversion rates of between 50 and 100%, preferably between 70 and 99%. The deoxygenation of the charge is between 30 and 100%, preferably between 50 and 99%.

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 filler, preferably with the biomass / solvent suspension. The catalyst promotes the hydrogenation of radicals from thermal cracking and reduces coke formation. When coke is formed, it is removed with 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) .The catalysts used may be heterogeneous solid powders ( such as natural ores, iron sulphate, etc.), dispersed catalysts derived from water-soluble dispersed catalyst ("water soluble dispersed catalyst") such as phosphomolybdic acid, ammonium molybdate, or A mixture of Mo or Ni oxide with aqueous ammonia, the catalysts used are preferably derived from soluble precursors in an organic phase ("oil soluble dispersed catalyst"). The precursors are organometallic compounds such as naphthenates of Mo, Co, Fe, or Ni, or Mo octoates, or multi-carbonyl compounds of these metals, for example 2-ethyl hexanoates of Mo or Ni, acetylacetonates of Mo or Ni, fatty acid salts C7-C12 of Mo or W, etc. They p 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 carbonaceous feedstock (which may be part of the feedstock to be treated, an external feedstock, a recycled fraction, etc.). the mixture is optionally dried at least in part, then or simultaneously is sulphurized by addition of a sulfur compound (H 2 S preferred) and heated. The preparations of these catalysts are described in the prior art. Additives may be added during the preparation of the catalyst or to the slurry catalyst before it is injected into the reactor. These additives are described in the literature. The preferred solid additives are inorganic oxides such as alumina, silica, mixed Al / Si 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 group VIB element (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. The particle size of the additive is 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%.

In the case of several reactors in series, the converted effluent from the first hydroconversion stage is optionally subjected to a separation of the light fraction. This light fraction contains very predominantly (at least 90% vol) compounds boiling at not more than 300 ° C, or even at most 450 ° 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 of cutting point, we could say that it is between 300 and 450 ° C. The residual effluent is at least partly, preferably wholly, treated in the second hydroconversion stage. This separation, called inter-stage separation, avoids overcracking of the light fraction in the second step. It also makes it possible to reduce the economic investment on the reactor of the second stage (less charge to be treated, less catalyst to inject, etc.) or to bring an external charge on the reactor of the second stage or of increase the residence time in the reactor of the second stage.

Figure 1 illustrates the invention. The installation and the method according to the invention are essentially described, without including the separation or the subsequent treatments of the separated fractions which will be described later. In FIG. 1, the roasted biomass feedstock (1), preferably previously dried and / or coarsely ground, is milled in the mill (2) in order to produce particles of suitable size to form a suspension and be more reactive under the conditions hydroconversion. The biomass is then brought into contact with the recycling solvent (VGO (96)) resulting from the process in the enclosure (3) to form the suspension. A sulfur compound to maintain catalytic activity may be injected (not shown) into the line exiting the enclosure. The suspension is preheated in the oven (4) and is then sent to the slurry hydroconversion reactor (9) which contains a slurry of catalyst (also called dispersed catalyst) injected through the pipe (5). The catalyst and an optional additive (6) can be injected either directly into the reactor via line (7), or into the chamber of the preparation of suspension (3) via line (8). It is also possible to provide a catalyst preparation chamber (not shown) in which the preparation of the catalyst is carried out before it is injected into the reactor (9) or into the chamber for preparing the suspension (3). The reactor (9) may contain an internal separation zone and a separate liquid recycle pump for dispersing the slurry catalyst and circulating it in the reactor under the conditions that fall under the conventional conditions of the slurry-driven beds. The method and the means for the preparation of the catalyst slurry are not shown in the figure, these means being widely described in the literature. The effluent from the reactor (9) withdrawn from the pipe (11) is subjected to separation, here in a separator (12) HPHT (high pressure, high temperature), to separate a light fraction by the pipe (13) and it is recovered by the pipe (14) the residual fraction. The hydrogen supply via the compressor (21) and the pipe (15) comes from the makeup hydrogen (31) and the recycled hydrogen (30). The hydrogen may be wholly (line 18) or partly (lines 18 and 19) heated in the furnace (17). In general, the management of the thermal levels is ensured by the final adjustment of the temperature of the slurry reactor (s) which is carried out on the one hand by the preheating furnace (17) of the recycle gas and of additional hydrogen and secondly by the possible bypass around this oven. This provision is not repeated in the other figures, to not weigh down the diagrams, but it is of general application and can be combined, in particular to the various embodiments described.

Separation The effluent obtained at the end of the hydroconversion stage undergoes at least one separation step, optionally supplemented by further additional separation steps according to different embodiments. In general, the effluent from the hydroconversion stage is sent to a separation section separating the gases (H2, H2S, NH3, H2O, C1-05 hydrocarbons, etc.), a heavy fraction containing solid particles of catalyst and one or more liquid fractions free of naphtha, kerosene, gas oil and vacuum gas oil (VGO) solids.

More specifically, the effluent obtained at the end of the hydroconversion stage is separated (generally in a high pressure high temperature HPHT separator) into a so-called light fraction which contains very predominantly (at least 90% vol.) The compounds boiling at not more than 200 ° C, or not more than 300 ° C, or not more than 450 ° C, and not more than 540 ° C; they correspond mainly to the compounds present in gases, naphtha, kerosene, light diesel or even heavy diesel. The other fraction is called the residual fraction. 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 of cutting point, we could say that it is between 100 and 300 ° C or 200 and 450 ° C, even 200-540 ° C. The so-called light fraction can be sent to a low temperature high pressure separator (HPBT) via a heat exchange equipment from which a gas phase containing the gases (H2, H2S, NH3, H2O, CO2, CO, C1 hydrocarbons) is recovered. -C4, ...), an aqueous phase and a liquid phase. The aqueous phase and / or the liquid phase of the low-temperature high-pressure separator (HPBT) are advantageously expanded in one or two low-temperature low-temperature separators (BPBT) so as to be at least partially degassed. An intermediate expansion step in a low temperature medium pressure separator (MPBT) may also be considered. The gases extracted from the HPBT separator undergo a purification treatment to recover the hydrogen and recycle it to the hydroconversion reactor (s) and / or subsequent treatments such as hydrotreatment and / or hydrocracking. It is the same for the gaseous effluents from any subsequent treatment units such as hydrotreating and / or hydrocracking of hydrocarbon cuts. The aqueous phase extracted from the HPBT separator essentially consists of oxygenated compounds (in particular phenols) and water being present initially (incomplete drying) or being produced during the hydrodeoxygenation reactions taking place during the hydroconversion or being introduced voluntarily. in the process to dissolve ammonium sulphide salts formed in the exchangers. Oxygenated compounds of the aqueous phase such as methanol, acetic acid or phenols can be recovered. In general, the elimination of the aqueous phase and the elimination or the recovery of the oxygenates can be carried out by all the methods and techniques known to those skilled in the art, such as for example by drying, passing through a desiccant or molecular sieve, flash, solvent extraction, distillation, decantation and membrane filtration or by combination of at least two of these methods. The aqueous phase is generally sent to a wastewater treatment plant comprising physicochemical and / or biological steps (activated sludge) and / or filtration and / or incineration steps.

The residual phases from the HPHT, HPLT and optionally MPBT and BPBT separators are advantageously sent to a fractionation system (also called non-integrated scheme) which comprises atmospheric distillation and / or vacuum distillation. Atmospheric distillation produces a gaseous effluent, so-called light fractions derived from atmospheric distillation, in particular containing naphtha, kerosene and diesel, and an atmospheric residue fraction. Vacuum distillation produces a fraction containing vacuum gas oil (VGO) and a heavy residue vacuum residue (VR) containing solids such as unconverted biomass and slurry catalyst particles. The products obtained can be integrated in fuel pools or undergo additional refining steps including hydrotreating and / or hydrocracking under high pressure of hydrogen. Part of the atmospheric distillates such as a portion of the diesel can be recycled as a solvent to the slurry preparation stage. All or part of the vacuum gas oil fraction (VGO) separated after the hydroconversion step can be recycled upstream of the hydroconversion reactor as a solvent to the suspension preparation step. The recycling of this phase, acting as a hydrogen donor solvent, provides a portion of the hydrogen necessary for hydroconversion. In order to increase its quality as a hydrogen donor solvent, the VGO preferably undergoes hydrotreating before recycling (optionally mixed with at least a portion of the recycled diesel fraction). Apart from its role as a solvent, the portion of the recycled VGO cut also represents raw material for the hydrocracking reactions in the hydroconversion reactor and thus allows an increase of the net conversion to fuel bases of the biomass. Part of the VGO can also be recycled to the enclosure for the preparation of the catalyst. Another part of the VGO can also be recycled directly into the slurry reactor.

The VGO-rich cup may also be used as a base for heavy fuel oil or bunker oil or sent to refinery units, such as hydrocracking or catalytic cracking units. The VGO rich cup can also be gasified to produce hydrogen. The heavy fraction containing the solid particles of catalyst (vacuum residue or atmospheric residue) may be partly (preferred) or completely recycled directly to the hydroconversion stage. It can be recycled in part or in full directly or after having undergone various treatments to regenerate the catalyst or extract it for valorization. One can be recycled directly and another regenerated and recycled.

When the residual catalytic activity of this catalyst is sufficient, a portion of said fraction can be recycled directly to the slurry hydroconversion stage. This is particularly the case when the conversion of the process is at least 95% wt, this fraction contains only few recoverable hydrocarbons, but contains the spent catalyst in concentrated form. This is also the case when it is obtained after the various separations a fraction containing the solid particles of catalyst but containing only few recoverable hydrocarbons. Generally, instead of recycling directly to the slurry reactor the heavy fraction containing the solid catalyst particles, it undergoes separation (s) and possible treatment (s) preparation of catalytic precursors - for example combustion, solvent washing, gasification or any other separation technique (these steps can be combined). This (these) treatment (s) make it possible to recover particles containing the slurry catalyst (or more exactly a catalyst precursor) which will be recycled to the catalyst preparation (thus including the sulfurization). The heavy fraction containing the solid particles of catalyst can therefore be recycled, in part or in full, to the preparation of the catalyst of the hydroconversion stage after undergoing separation (s) and possible treatment (s) preparation of catalytic precursors such as combustion, solvent washing, gasification or any other separation technique. Such methods of treatment are well known to those skilled in the art. Alternatively, a part of the heavy fraction containing the solid catalyst particles (especially the vacuum residue) may, optionally after separating the solid particles of catalyst for recovery or recycling, be burned by the For example, in a cement kiln or to supply energy on site, or can supply a gasification unit to produce hydrogen and energy. The hydrogen thus produced can be introduced into the hydroconversion process and / or in the subsequent hydrocracking and / or hydrotreatment treatments.

Figure 1 shows, in general, the separation scheme of the hydroconversion effluent and the hydrogen recycling loop. In this embodiment, the separated phase in the pipe (13) is a gaseous phase containing hydrogen, the gases resulting from the hydroconversion (NH 3, H 2 S, H 2 O, CO, CO2, etc.) and hydrocarbons. light (C1-C4). The gas phase is here cooled in the cooler (32) before being sent to the separator (33) HPLT (high pressure, low temperature) to separate a hydrogen-rich gas (34) sent to the gas treatment, an aqueous phase. (39) and a liquid hydrocarbon fraction (35). The residual liquid fraction (14) from the separator (12) HPHT (high pressure, high temperature) is sent in the continuation of the separation section. This comprises a high temperature medium or low pressure separator (36) which separates a gas phase (37) sent to the gas treatment unit 25 described below. Here, it is shown that this phase (37) can be pre-cooled (80), separated at low temperature (81) to improve its purification. The liquid fraction (generally a fraction containing predominantly compounds boiling at at least 150 ° C) (line 83) is treated with fraction (35), this being preferred. The gas phase (line 84) is sent to the gas treatment unit. An aqueous phase (82) is also recovered.

At the end of the separator (36), a residual liquid phase (38) is obtained which can be fractionated (90) (distillation or atmospheric flash and distillation or flash under vacuum), with the fraction (35) to obtain the GPL fractions (C3, C4) (91), naphtha (92), kerosene, (93), gas oil (94), VGO (vacuum distillate) (95) and VR (vacuum residue) (97). This fraction (s) naphtha, kerosene, gas oil and VGO are preferably subjected to a treatment to bring them to the required specifications. At least a portion of the VGO (96) is preferably recycled to the enclosure (3) to form the biomass / solvent suspension, preferably after being hydrotreated (99) prior to recycling.

At least a portion of the VR (98) containing the slurry catalyst particles may be recycled, preferably after various treatments to regenerate the catalyst, to the slurry reactor (9) or to the preparation of the catalyst (not shown).

Figure 1 also illustrates, in general, the recycling hydrogen loop. This loop conventionally comprises a purification treatment of hydrogen. The hydrogen-rich gas treatment unit conventionally comprises an HP (high pressure) adsorber (25) and a membrane unit (26), the hydrogen thus separated is sent via the pipe (24) to the compressor (21) then that the residual gas can be treated with PSA ("pressure swing adsorption") (27) to separate the residual hydrogen, also sent in compression, the contaminants going to fuel gas (28).

Subsequent treatments The recovery of the various fuel base cuts is not the subject of the present invention and these methods are well known to those skilled in the art. In general, the fraction (s) naphtha, kerosene, gas oil and VGO may be subjected to one or more treatments (hydrotreating, hydrocracking, alkylation, isomerization, catalytic reforming, catalytic or thermal cracking or other) for bring to the required specifications (sulfur content, smoke point, octane, cetane, etc.) separately or in a mixture. The naphtha can be hydrotreated in a dedicated unit, or it can be sent to a hydrocracking unit where it is brought to the characteristics of a load acceptable for catalytic reforming and / or isomerization. Kerosene and product gas oil can undergo hydrotreatment followed by hydrocracking to specifications.

In general, hydrotreating and / or hydrocracking after hydroconversion can be done either conventionally via an intermediate conventional separation section as described in FIG. 2 (and called non-integrated scheme), or directly integrating the hydrotreatment / hydrocracking section with the hydroconversion section with or without prior separation of the effluents and without intermediate decompression between the two stages as described in Figure 3 (and called integrated scheme). According to a variant of the invention, the liquid fraction (s) free of solids obtained by at least one separation are partly or wholly subjected to a hydrotreatment and / or hydrocracking step with intermediate decompression.

According to another variant of the invention, the solids-free liquid fraction (s) obtained by at least one separation partially or completely undergo a step of hydrotreatment and / or hydrocracking without intermediate decompression.

FIG. 2 illustrates the non-integrated diagram, that is to say with decompression between the hydroconversion reactor and the treatment of the effluent, advantageously with a single compression system. The separation section of the residual fraction (14) comprises atmospheric distillation (40) and vacuum distillation (41). The product gas oil (line 42) is hydrotreated (43) to specification (sulfur content, cetane, aromatic content, etc.). After fractionation (unit 44), the gas oil is recovered as well as the lighter fractions which could have been produced, including a gas rich in hydrogen (54), which after a purification treatment (45) is sent to the compressor (21) n stages (the 3rd stage is here adequate) (conduit 46). VGO (vacuum gas oil, line 47) is hydrocracked (48) and fractionated (49). The naphtha (56) may be hydrotreated in a dedicated unit, or may be sent to the diesel hydrotreating unit or the hydrocracking unit where it is brought to the characteristics of a catalytic reforming acceptable feedstock. On the gas phase duct (13), the HPLT separator (high pressure, low temperature) (33) which separates a hydrogen-rich gas (50) which, after treatment (51), is sent (lines 52, 53) at the proper stage of the compressor. Advantageously, a single compressor (21) with n stages (here 3, with the highest pressure at the nth stage) is used and the hydrogen for the treatment (43) of the diesel (hydrotreatment) will be provided by a intermediate stage (here the 21st), while the method according to the invention will be fed by the 3rd stage of the compressor (55). The use of this unique n-stage compressor with hydrogen recycling and a clever combination of units allows optimized hydrogen management to ensure the correct coverage rate (H2 / HC) at the reactor (s). ) in a bubbling bed and slurry reactor (s). There could have been two separate compressors, one for make-up hydrogen and one for recycling hydrogen.

Fig. 3 shows an embodiment according to the integrated scheme, that is to say without decompression between the hydroconversion reactor and the treatment of the effluent.

Through the conduit (11) arrives the effluent from the hydroconversion stage, it passes into the HPHT separator (high pressure, high temperature) (70) to separate a hydrocarbon fraction (line 56) containing very predominantly (at least 90%) compounds with a boiling point of not more than 540 ° C, or not more than 450 ° C or not more than 440 ° C.

The residual fraction (line 57) contains, for the most part (at least 90%), compounds with a boiling point greater than 440 ° C., or even 450 ° C. or 540 ° C. In the same way as before, the separation is not clear; if it were necessary to give a cutting point, it would be between 440 and 540 ° C, preferably between 450 and 540 ° C.

This residual fraction is distilled under vacuum (58) in order to recover the recoverable VGO (gas oil under vacuum) (line 59) and a residue under vacuum (line 60) on which the slurry catalyst will be recovered according to methods already mentioned. The VGO (59) can be recycled upstream of the hydroconversion reactors to form the biomass / solvent suspension. The lighter fraction (56) is only hydrotreated (for example before shipment to the FCC, fluidized catalytic cracking unit) or hydrotreated and hydrocracked (hydrotreatment 61 followed by hydrocracking 62) in the presence of hydrogen (68) and effluent is fractionated (63) to obtain a LPG cut (C3-C4) (71), naphtha (64), kerosene (65), diesel (66) and VGO (67). In the case of a hydrocracking with recycling of VGO (67), the conversion of the charge into light and medium distillates (LPG, naphtha, kerosene, diesel) is then total.

An external cut generally coming from another process existing in the refinery or possibly outside the refinery (line 69) can be brought before the hydrotreatment; advantageously the external cut is for example the VGO from fractionation of crude oil (VGO straight-run), the VGO resulting from a conversion, a LCO (light cycle oil) or a HCO (heavy cycle oil) FCC. Very advantageously, it is sent to hydrotreatment or hydrocracking with all or part of the VGO generated by the distillation of the residual fraction (line 72). The advantage of this process is its integration at the pressure and thermal levels, hence a process that consumes less energy overall and emits less CO2. This configuration has technical and economic advantages since the high pressure streams will not require an increase in pressure for their further refining. Another advantage is the obtaining of products (kerosene, diesel, VGO which can serve as oil bases for example) directly to the specifications (sulfur, cetane ...) by the adjustment of the operating conditions (in the forms of known conditions) according to the separated fraction (56).

The example below illustrates the invention and its interest.

EXAMPLE This example compares the performance of the hydroconversion process on a roasted biomass feedstock (according to the invention) and unrefined biomass (not according to the invention). In the example according to the invention, the biomass load considered is beech, previously roasted at 250 ° C. for 1 hour, crushed and sieved so as to obtain particles smaller than 100 microns (see simplified composition Table 1) . The filler is mixed with tetralin before introduction into the reactor. Inorganics are mainly composed of ash and metals, traces of chlorine and sulfur.

Table 1: Simplified composition of load load beech unroasted roasted water% m / m 1.7 8.1 C organic% m / m 53.3 43.4 H organic% m / m 5.6 5.5 O organic% m / m 38.4 41.5 inorganic% m / m 0.9 1.5 The example was carried out on a representative autoclave of the slurry reactor process. The use of tetralin as a donor solvent is well known and can be likened to the recycling of at least a portion of a fraction resulting from the fractionation of the effluent from the reaction section. In a 500 ml stainless steel autoclave, 72.3 g of biomass were introduced with 144.8 g of an organic phase containing predominantly tetralin and 300 ppm weight of metals in sulphide form. This organic phase containing the sulphurized metals was previously prepared in an autoclave from tetralin, an ammonium molybdate solution and a nickel nitrate solution and the use of dimethyl disulfide (DMDS) as an agent. sulphurant, by heating under hydrogen pressure. The autoclave was closed and inerted by several pressurization / nitrogen depressurization sequences. Hydrogen was then introduced at an initial pressure of about 7.5 MPa and then the autoclave was heated to 400 ° C and this temperature was maintained for 4 h. The pressure at this temperature reached 16 MPa and was maintained by adding H2 to compensate for H2 consumption. The autoclave was then cooled and depressurized.

In order to quantify the beneficial effects of the previous roasting step on slurry hydroconversion, a second experiment was carried out on an unrefined beech load. As shown by the elemental analysis of the unrefined feedstock (see simplified composition Table 1), the sum of organic matter content sought (carbon, hydrogen) is lower than that of the roasted feed (effect of roasting). Since these organic elements can be regarded as precursors of products derived from hydrocarbon-type biomass and are therefore easily recoverable, they should be introduced in equal amounts in this example not according to the invention compared to the example according to the invention. invention. Thus, the mass of unrefined biomass introduced is 87.1 g, which corresponds to the same sum of the carbon and hydrogen compound masses as in 72.3 g of roasted biomass. Except this load difference, all the other conditions are equal and the manipulations are identical to those carried out in the example according to the invention.

The recipe obtained in each case was filtered to separate the liquid and the solids. The solid fraction was washed with ether and dried. The mass of solids derived from the biomass is equal to the amount of solids recovered (after washing and drying). The mass of biomass solids is used to calculate the conversion of biomass introduced according to the following formula, the numerical application of this formula is shown in Table 2: Conversion = 100 - (100 x mass of solids from biomass / mass of biomass introduced) Table 2: Calculation of conversion beech load unroasted roasted beech initial biomass load g 72.3 87.1 solids from biomass g 0.5 2.1 conversion% m / m 99.3 97.6 Elemental analysis was carried out on the liquids obtained (see Table 3).

Table 3: Elemental analysis of the liquid fraction obtained organic roasted non-roasted beech beech load% m / m 90.2 90.1 Organic H% m / m 9.7 9.6 Organic O% m / m 0.1 0.3 From the oxygen content measured in the liquid fraction and the mass of liquid obtained, it is possible to calculate the amount of oxygen in the liquid. The amount of organic oxygen is calculated from the oxygen content of the biomass feed (see Table 1) and the biomass feedstock. The tetralin solvent is oxygen free. It is therefore possible to calculate a deoxygenation rate according to the following formula, the numerical application of this formula is shown in Table 4: Deoxygenation rate = 100 - (100 x mass of oxygen liquid fraction / mass of oxygen biomass introduced )

Table 4: Calculation of deoxygenation load beech unroasted roasted beech Biomass load g 72.3 87.1 O organic load% 38.4 41.5 m / m O organic feed g 27.8 36.2 Liquid fraction g 160.3 160.9 O organic fraction liquid% 0.1 0.3 m / m O organic liquid fraction g 0.2 0.5 Deoxygenation rate biomass% 99.4 98.6 m / m The liquid fraction was distilled to remove tetralin and decalin (formed by partial hydrogenation of tetralin). Liquids with strictly lower boiling points and strictly superior to tetralin and decalin have been grouped together. The mass of liquid obtained makes it possible to calculate a yield of liquids from the biomass with respect to the mass of biomass introduced. The yield of gas from biomass can be estimated by the difference between the conversion and the liquid yield (see Table 5) Table 5: Calculation of yields of liquids and gases from biomass feed beech roasted beech unrefined Biomass feedstock initial g 72.3 87.1 Biomass liquids g 23.5 20.6 Liquid yields from biomass% 32.0 23.7 m / m conversion% 99.3 97.6 m / m Gas yields from biomass% 66.8 73.9 m / m Spot analyzes have shown that these Biomass gases were essentially light hydrocarbons of 1 to 6 carbon atoms, water, carbon monoxide and dioxide, hydrogen sulfide and ammonia.

On the liquid obtained after removal of the solvent, elemental analysis was carried out so as to determine the contents of C, H and O (see Table 6), as well as a gas phase chromatography to obtain a simulated distillation. The exploitation of the simulated distillation makes it possible to estimate the selectivities of different cuts present in the liquid resulting from the biomass after removal of the solvent (see Table 7). Table 6: Elemental analysis of the liquid from the biomass after removal of the solvent charge beech non-roasted beech roasted organic C% m / m 88.5 87.7 H organic% m / m 10.8 10.2 O organic% m / m 0.7 2.120 Table 7: Selectivities of liquid cuts from biomass feed beech unroasted roasted beech PI-177 ° C (naphtha cut)% m / m 39 42 177-232 ° C (kerosene cut)% m / m 17 21 232 ° C-343 ° C ( The non-compliant example of the invention shows that the use of unrefined biomass results in a lower conversion of the biomass, an amount of less than 1% of the biomass. gas produced increased at the expense of the amount of liquid and a lower rate of oxygen deoxygenation compared to the hydroconversion of roasted biomass carried out under the same conditions. The liquids resulting from the hydroconversion into slurry from unrefined biomass therefore have qualities that are more distant from the finished products such as fuels and will therefore have to undergo even more severe refining steps than if the hydroconversion into slurry had been carried out. from roasted biomass. In a process according to the invention, the recycling of VGO (fraction included in 343 ° C +) will further increase the yield of recoverable products, especially liquids.

Claims (15)

REVENDICATIONS1. A method of hydroconversion of biomass selected from lignocellulosic biomass and / or one or more lignocellulosic biomass components selected from the group consisting of cellulose, hemicellulose and lignin to produce fuel bases comprising: a. a step of preparing a suspension of the biomass particles in a solvent, b. then at least one hydroconversion step in the presence of hydrogen in at least one reactor containing a dispersed catalyst, and optionally a solid additive, c. then at least one step of separation of the effluent from the hydroconversion stage, characterized in that said biomass is subjected to a pretreatment comprising a roasting step prior to the preparation of the suspension. 2. Method according to the preceding claim wherein the roasting step is carried out at a temperature between 200 and 300 ° C, preferably between 225 ° C and 275 ° C in the absence of air. 3. Method according to one of the preceding claims wherein the pretreatment further comprises at least one of the following steps: a. a drying step carried out at a temperature below 250 ° C, preferably below 200 ° C, b. a grinding step. 4. Method according to one of the preceding claims wherein, after pretreatment, the biomass particles have a moisture of 1 to 50%, preferably 1 to 35% and more preferably 1 to 10% and a particle size less than 600 μm, preferably less than 150 μm. 31 5. Method according to one of the preceding claims wherein the hydroconversion step is carried out at a temperature between 300 ° C and 450 ° C, at a total pressure of between 2 and 35 MPa, at an hourly mass velocity included between 0.1 and 5 h -1 and at a hydrogen / charge ratio of between 0.1 and 2 Nm 3 / kg. 6. Method according to one of the preceding claims wherein the dispersed catalyst is a sulfide catalyst containing at least one element selected from the group consisting of Mo, Fe, Ni, W, Co, V, Ru. 7. 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 has a particle size of less than 1 mm. 8. Method according to one of the preceding claims wherein the biomass is co-treated with a filler selected from petroleum residues, crude oils, heavy or extra heavy crude oils, synthetic crudes, crude head oils, oils deasphalted resins, deasphalting resins, deasphalting asphalts, derivatives of petroleum conversion processes, oil sands or derivatives thereof, oil shales or their derivatives, coal or coal liquefied coal obtained by hydroliquefaction, hydrocarbon waste and industrial polymers, organic waste or household plastics, vegetable or animal oils and fats, tars and residues that are not or not easily recoverable from the gasification of biomass, coal or petroleum residues, charcoal, olive oil pyrolysis, activated sludge, algae or mixtures of such fillers. 9. Method according to one of the preceding claims wherein the effluent from the hydroconversion stage is sent to a separation section separating the gases, a heavy fraction containing solid particles of catalyst and / or liquid fractions without solids of the naphtha type, kerosene, diesel and vacuum gas oil. 10. Method according to the preceding claim wherein the liquid fraction (s) free (s) solids and having a distillation range in the range of 180 ° C to 550 ° C, preferably 200 ° C to 550 ° C ° C, is / are recycled (s), in part or in full, as a solvent to the suspension preparation step. 11. The method of claim 10 wherein the recycled fraction (s) undergoes / undergoes hydrotreatment prior to its / their recycling in the suspension. 12. The method of claims 9 to 11 wherein the heavy fraction containing the solid catalyst particles is recycled, in part or in full, directly to the hydroconversion stage. 13. Process according to claims 9 and 12, in which the heavy fraction containing the solid catalyst particles is recycled, partly or wholly, to the preparation of the catalyst of the hydroconversion stage after undergoing separation (s) and possible process (es) for the preparation of catalytic precursors such as combustion, solvent washing, gasification or any other separation technique. 14. The method of claims 9 to 13 wherein the liquid fraction (s) free of solids obtained by at least one separation are partially or completely undergo a step of hydrotreatment and / or hydrocracking with intermediate decompression 15. The method of claims 9 to 13 wherein the liquid fraction (s) free of solids obtained by at least one separation are partially or completely undergoes a step of hydrotreating and / or hydrocracking without intermediate decompression.