Method for treating a liquid carbonaceous feedstock resulting from a hydrothermal liquefaction treatment
Patent Information
- Authority / Receiving Office
- AU · AU
- Patent Type
- Applications
- Current Assignee / Owner
- IFP ENERGIES NOUVELLES
- Filing Date
- 2024-12-02
- Publication Date
- 2026-07-30
AI Technical Summary
The biocrude obtained from hydrothermal liquefaction of biomass contains high levels of mineral compounds, particularly metallic ones, which poison catalysts used in subsequent treatment processes, making it necessary to purify the biocrude to facilitate successful conversion into biofuels or chemical products.
A process integrating hydrothermal liquefaction with a treatment step to reduce mineral compound content in biocrude, involving mixing with catalysts and a liquid phase, followed by liquefaction, liquid/liquid/gas separation, and counter-current liquid/liquid extraction with an aqueous solvent to deplete biocrude of mineral compounds.
The process effectively reduces the content of mineral compounds in biocrude by at least 50% (by weight), allowing for successful conversion into biofuels and chemical products without disrupting subsequent conversion reactions, while also reducing water consumption and catalyst usage.
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Abstract
Description
[0001] PROCESS FOR TREATING A LIQUID CARBONACEOUS FEED FROM A HYDROTHERMAL LIQUEFACTION TREATMENT
[0002] Technical Field
[0003] The present invention relates to the production of recoverable chemical products or biofuels from biomass, in particular lignocellulosic biomass. More specifically, the invention concerns biomass hydrothermal liquefaction processes, also known by the acronym HTL according to their Anglo-Saxon name "HydroThermal Liquefaction", which make it possible to transform biomass into a carbonaceous feedstock known as "biocrude". This feedstock known as "biocrude" must then be treated, in particular by hydroconversion, hydrotreatment, hydrocracking, catalytic cracking, to obtain the desired chemical products with the desired specifications.
[0004] Prior art
[0005] Hydrothermal liquefaction (for more details, please refer to the publication “Continuous Hydrothermal Liquefaction of biomass: a critical review”, D. Castello, TH Pederson, LA Rosendahl, Energies 2018, 11, 3165) is a process for converting a feedstock in the presence of water at a pressure between 100 and 350 bar (between 10 7 Pa and 3.5.10 7 Pa) and at a temperature between 250 and 450°C. Catalysts can be used for hydrothermal liquefaction: pH modifier, NaOH, KOH, K2CO3, Na2CC>3, etc.
[0006] The products of hydrothermal liquefaction are called "biocrude," consisting mainly of organic molecules, an aqueous phase comprising water-soluble organic compounds (alcohols, acids, ketones, phenols, etc.) and salts, gas, and possibly biochar. Biochar is a solid product rich in carbon, "char" coming from the English word "charcoal." The gas produced is mainly CO2 but can also contain hydrogen, methane, and CO.
[0007] In the hydrothermal liquefaction process, water can be present as a liquid or in a relatively dense supercritical state. Water near the critical point (374°C, 221 bar) has very different properties from water at room temperature. These near-critical properties allow water to play several roles in the conversion process, such as being a reactant, a catalyst, or a source of hydrogen. Near the critical point or in the supercritical state, water has properties that facilitate liquefaction, such as a low dielectric constant that allows solubilization of nonpolar molecules and a sufficiently high ionic product to favor ionic reactions leading to liquid products over free-radical reactions leading to solid or gaseous products.
[0008] The reactions occurring in the hydrothermal liquefaction process are numerous and complex, but include depolymerization reactions including hydrolysis, dehydration, decarboxylation, and repolymerization reactions including condensation.
[0009] The yields and composition of the biocrude depend on the operating conditions, but also on the feedstock treated by hydrothermal liquefaction. For example, for a feedstock consisting of wood, a mass yield of biocrude of around 40-45% and gas yield of 40-45% are obtained by hydrothermal liquefaction.
[0010] The feedstock for hydrothermal liquefaction may be biomass, preferably selected from plants, grasses, trees, wood chips, seeds, fibers, seed coats, aquatic plants, algae, hay and other sources of lignocellulosic materials, such as, for example, those from organic waste, municipal waste, agro-food waste, animal waste, forestry waste, sawmill waste, slaughter residues, agricultural and industrial waste (such as, for example, sugarcane bagasse, waste from oil palm cultivation, sawdust or straw). The feedstock for hydrothermal liquefaction may also come from pulp and paper by-products, whether recycled or not, or from by-products from paper mills, waste such as used plastics, used tires. The feedstock may also be a mixture of at least two of these materials.
[0011] Biocrude obtained by hydrothermal liquefaction is a complex mixture of compounds, consisting mainly of hydrocarbons and oxygenated compounds. In general, the oxygenated compounds are organic acids, ketones, oxygenated aromatic compounds, alcohols, aldehydes, esters, ethers and water. Water generally represents less than 15% by weight of the biocrude. In the case of a lignocellulosic biomass feedstock, the biocrude contains compounds derived from cellulose, hemicellulose and lignin (a structure present in lignocellulosic biomass).
[0012] The biocrude obtained by hydrothermal liquefaction has an oxygen, sulfur and nitrogen content that varies greatly depending on the hydrothermal liquefaction load (algae, wood, etc.). For example, biocrude from hydrothermal liquefaction of wood generally consists of 5 to 20% by weight of oxygen, less than 0.5% by weight of sulfur and less than 5% by weight of nitrogen in the dry biocrude (without water).
[0013] Biocrude can contain up to 4% by weight of inorganic (mineral) compounds, mainly metals such as sodium, potassium but also calcium, iron, etc. These mineral compounds can come from the catalysts used for hydrothermal liquefaction, from the hydrothermal liquefaction feedstock itself, and from metals possibly used to grind the hydrothermal liquefaction feedstock. Sodium and potassium can be present in relatively large quantities in biocrude, as the hydrothermal liquefaction process generally uses alkali-based catalysts (NaOH, KOH, K2CO3, Na2CO3...) in significant quantities.
[0014] This content of inorganics, especially metals, generally does not allow the use of biocrude as fuel because the quantity of ash is too high.
[0015] To be transformed into biofuels (gasoline, kerosene, diesel, marine fuel) or into chemical products, the biocrude must be treated, in particular to reduce the heteroatoms and more particularly the oxygen it contains. This treatment may include at least one operation chosen from hydroconversion, hydrotreatment, hydrocracking, or catalytic cracking. However, these operations use catalysts known to those skilled in the art to be sensitive to metal content (in particular alkali or alkaline-earth metals such as Na, K, Ca, etc.). These metals in fact poison the catalysts: they deactivate them at least partially.
[0016] It is therefore necessary to purify the biocrude, that is to say to reduce its content of mineral compounds, particularly metallic ones, so that its subsequent treatments can be carried out successfully.
[0017] Patent applications WO18177877, WO19092173, WO21121662 disclose treatments aimed at purifying biocrudes, and in particular at recovering the metal salts they contain for recycling, with different types of separation devices, using acidic aqueous phases or even washing agents, but the implementation and implementation of these separation / treatment operations appear complex.
[0018] The invention therefore aims to develop a hydrothermal liquefaction process integrating a treatment of the product obtained, biocrude type, to reduce its content of mineral compounds, particularly metallic ones, a process which is preferably simple to implement, and preferably economical in terms of tools and / or utility consumption.
[0019] Summary of the invention
[0020] The invention firstly relates to a process for the hydrothermal liquefaction of an initial carbonaceous charge at least partly derived from biomass, in order to obtain a so-called biocrude product with a reduced content of mineral compounds, said process comprising the following steps:
[0021] - step a) of mixing the initial carbon feedstock with at least one catalyst and at least one liquid phase, including at least one first aqueous phase containing all or part of the catalyst and optionally at least one first organic phase,
[0022] - step b) of hydrothermal liquefaction of the mixture obtained in step a), in order to obtain a liquefaction product,
[0023] - step c) of liquid / liquid / gas separation of the liquefaction product obtained in step b), in order to obtain a first gaseous phase, a second liquid aqueous phase and a second liquid organic phase called biocrude, (part of which is optionally recycled as an organic phase in step a) of mixing),
[0024] - step d) of separation by heating of the second aqueous phase obtained in step c), in order to obtain a third liquid aqueous phase enriched with minerals originating at least from the catalyst used in step a) of mixing, and a first phase of water vapor,
[0025] - step e) of diluting the second liquid organic phase called biocrude obtained in step c) with a diluent which comprises an organic liquid phase which has a viscosity and a density lower than that of said second liquid organic phase called biocrude, so as to obtain a diluted biocrude,
[0026] - a step f) of contacting the diluted biocrude obtained in step e) with at least one solvent which comprises a liquid aqueous phase, with counter-current liquid-liquid extraction, so as to obtain, on the one hand, a raffinate comprising the biocrude depleted in mineral compounds and diluent, and on the other hand an extract comprising the solvent enriched in mineral compounds,
[0027] - a step g) of separation of the raffinate obtained in step f) of contacting, so as to obtain, on the one hand, the biocrude depleted in mineral compounds, and, on the other hand, a phase comprising the diluent,
[0028] - a step h) of condensation of a first part of the first vapor phase obtained in step d) and of recycling said part of the first vapor phase once condensed as a solvent in step f) of contacting,
[0029] - a step i) of at least partial recycling of the extract obtained in step f) of contacting to step d) of separation by heating,
[0030] - a step j) of separating at least a second part of the first vapor phase obtained in step d), in order to obtain a fourth aqueous phase, and a first so-called light organic phase optionally recycled as an organic phase in step a) of mixing.
[0031] It should be noted that several of these steps can be carried out in the same device or set of devices. Thus, mixing and liquefaction can be carried out in the same equipment, or not.
[0032] It should also be noted that the recycling steps mentioned can be carried out in the form of recycling loop(s) of a fluid considered, that they can therefore be carried out continuously or discontinuously in the process, and that the statement of the steps does not mean that the steps are necessary successive and consecutive: the process can include other optional steps, in addition to the recycling steps which can take place throughout the process or during a certain period of it.
[0033] It should be noted that, for all the recycling described in this text, the recycling may only be partial, that is to say that the entire flow considered or only part of said flow may be recycled, and that, in addition, this recycling may be supplemented by the addition of an external flow (for example, the addition of external water when the flow to be recycled is of the aqueous type, or the addition of external organic products when the flow to be recycled is of the organic type).
[0034] An aqueous phase is understood to mean a phase that is predominantly, in particular essentially aqueous, but which may contain soluble organic compounds and / or mineral compounds. Similarly, an organic phase is understood to mean a phase that is predominantly, in particular essentially organic, but which may contain a (low) content of water and / or other compounds, such as mineral compounds.
[0035] The invention, if we can summarize it synthetically, therefore consists of integrating into a single process
[0036] - on the one hand a hydrothermal liquefaction process of a load comprising biomass, (with premixing, liquefaction and liquid / liquid / gas separation)
[0037] - and on the other hand the treatment of the biomass feedstock once liquefied to deplete it of mineral compounds (with dilution, liquid / liquid extraction and separation), so that it can then be converted conventionally without the mineral compounds (too much) disrupting the subsequent conversion reactions.
[0038] This allows us to retain the type of catalyst usually used for these conversion stages such as hydroconversion, hydrotreatment, hydrocracking, or even catalytic cracking.
[0039] And this integration is very advanced, with very relevant recycling which makes it possible to reduce or even eliminate the consumption of certain utilities in the process as a whole, and we can provide both recycling internal to the liquefaction, recycling internal to the treatment of depletion of mineral compounds from the liquefied biomass, and recycling between the liquefaction and the depletion treatment.
[0040] Thus, recycling according to step i) of the extract obtained in the contacting step to the separation step d) is very advantageous: this extract, as detailed below, is an aqueous solution rich in mineral compounds, and recycling it in the separation step d) will allow these mineral compounds to be recycled, ultimately, to the liquefaction step b): these mineral compounds are in particular metallic compounds originating from the catalysts used in the liquefaction. This recycling therefore makes it possible to reduce or even eliminate the consumption of catalysts in the hydrothermal liquefaction step of the biomass.
[0041] And step h) of condensing a first part of the first vapor phase (22) obtained in step d) and recycling said first part of the first vapor phase once condensed as a solvent in step f) is also very advantageous, because it also contributes to reducing the water consumption of the process as a whole.
[0042] Furthermore, the treatment of biocrude, resulting from separation step c) after liquefaction b) in order to reduce its mineral content, is also very efficient in itself: And to do this, the treatment first uses dilution with a "light" organic diluent (less dense and less viscous than biocrude), then countercurrent liquid / liquid extraction with an aqueous solvent. And it has proven that this dilution + extraction combination is very efficient.
[0043] Countercurrent liquid / liquid extraction can be implemented quite simply, using a gravity extraction type extraction column for example (or several in series or in parallel).
[0044] Carrying out an extraction in such a column requires a sufficient difference in density between the phases present (often greater than 50 kg / m 3), and the greater the difference in density, the easier this implementation will be. Furthermore, the viscosity of one or both phases plays an important role in this operation, because the more it increases, the more the transfer of material between phases will be slowed down on the one hand, and the more the capacity of the column risks decreasing, in terms of possible charge flow rate per unit of column section. Countercurrent columns are interesting because they allow the desired solutes to be extracted much better than in a co-current column or in a stirred tank. Indeed, the number of theoretical stages can reach high values (between 2 and 15 in the vast majority of cases), and with minimized solvent consumption.
[0045] Advantageously, the first so-called light organic phase obtained in step j) can be at least partly recycled as the first organic phase in mixing step a).
[0046] Advantageously, at least part of the second liquid organic phase (18) called biocrude obtained in step c) of liquid / liquid / gas separation can be recycled as first organic phase (4) in step a) of mixing,
[0047] Advantageously, the method according to the invention may comprise a step k) of at least partial recycling of the phase comprising the diluent obtained in step g) of separation as diluent in step e) of dilution. This recycling may be partial or total: it may be supplemented by an addition of external diluent, if necessary, but it is very advantageous, because it makes it possible to drastically reduce the consumption of diluent in the treatment method according to the invention.
[0048] Advantageously, the method according to the invention may comprise a step I) of at least partial recycling of the phase comprising the diluent (28) obtained in step g) of separation in step c) of liquid / liquid / gas separation (8). This recycling of the phase comprising the diluent, which in fact is a light fraction of biocrude, at the level of the liquid / liquid / gas separation c) has proven to improve the liquid / liquid / gas separation.
[0049] Advantageously, the method according to the invention may comprise a step m) of at least partial recycling of the third liquid aqueous phase to the mixing step a). This phase is aqueous and may contain mineral compounds; its recycling to the mixing step a) makes it possible to reduce both the consumption of water and catalyst for hydrothermal liquefaction.
[0050] Advantageously, the method according to the invention may comprise a step of at least partial recycling of the first organic phase and / or the second organic phase to the mixing step a) (via stream 4 detailed below). This possibility of additional recycling makes it possible to reduce the consumption of organic phase necessary for the mixing operation prior to liquefaction.
[0051] Preferably, step b) of hydrothermal liquefaction comprises heating, at a temperature between 250°C and 450°C under a pressure between 100 bar (10 7 Pa) and 350 bar (3, 5.10 7 Pa), in the presence of at least one catalyst containing at least one pH modifier and / or an alkali, such as Na or K, and / or an alkaline earth such as Ca.
[0052] Preferably, the diluent used in dilution step e) is chosen from a light cut present in the biocrude feed or a chemical compound or mixture of chemical compounds, in particular from the family of alcohols, ethers, ketones and hydrocarbons. The process can be started with a diluent with a boiling temperature close to that of the phase comprising the diluent to be recycled according to step g), which is a light cut of the biocrude, then this phase will gradually accumulate in the recycling loop over time and will thus gradually replace the initial diluent.
[0053] Preferably, during dilution step e), the diluent has a final boiling point of at most 150°C, preferably at most 100°C.
[0054] Preferably, at the end of dilution step e), the diluted biocrude has a dynamic viscosity at 20°C of at most 7 cP, preferably at most 4 cP, and a density at 15°C of at most 950 kg / m 3 , preferably not more than 900 kg / m 3 .
[0055] Preferably, during dilution step e), the ratio R of the flow rate Qd of the diluent to the flow rate Qb of the biocrude is at most 10, and in particular at least 0.1, the ratio R preferably being between 0.5 and 3.
[0056] Preferably, contacting step f) is carried out at a pressure of between 0.5.10 5 Pa and 15.10 5 Pa, and at a temperature between 15 and 150°C, while remaining below the boiling point of the diluent at contact pressure.
[0057] Preferably, separation step d) and / or separation step g) is a treatment comprising at least one evaporation, one distillation, one heating followed by one separation.
[0058] Preferably, the diluent used in dilution step e) is chosen from a light cut present in the biocrude load or a chemical compound or mixture of chemical compounds, in particular from the family of alcohols, ethers, ketones and hydrocarbons.
[0059] Preferably, the solvent used in contacting step f) is chosen from at least one of the following solutions: a pure aqueous solution, a demineralized aqueous solution, an aqueous solution containing soluble organic compounds, an acidic aqueous solution. In the case of an acidic aqueous solution, it may contain from 10 ppm to 20% by weight of a strong or weak organic or mineral acid, such as acetic acid, nitric acid, sulfuric acid, hydrochloric acid, citric acid, oxalic acid, lactic acid, formic acid or any other acid. Preferably, as seen above, all or part of this solvent used for contacting f) comes from the recycling of at least part of the first vapor phase from separation step d), once condensed.
[0060] A single type of solvent can be used, for example injected into the upper part, at the head of the column carrying out the liquid / liquid extraction (when it is oriented vertically), with a possible second injection point at an intermediate height. Alternatively, two separate solvents can be used, brought into contact with the diluted biocrude in separate contact zones, for example with the first injected into the upper part / head of the column and the second at an intermediate height of the column.
[0061] These two options can also be combined, preferably with the second injection point of the first solvent at a column height lower than the injection point of the second solvent:
[0062] - For example, at least one of the inlets of the second solvent is at an intermediate height of the column, in particular at a height H2 relative to the total height H of the column such that the ratio H2 / H is between 0.2 and 0.8.
[0063] - It is also possible that it is rather one of the inlets of the first solvent which is at an intermediate height of the column, in particular at the H2 height in question.
[0064] The total height H is understood to mean the useful height of the column, as is known in the field of liquid-liquid extraction or distillation columns. If the first solvent (or the second solvent) has a second inlet in the column at an intermediate height H3, then this intermediate height H3 is preferably less than the height H2 of the inlet of the second solvent (or first solvent). Advantageously, this height H3 of the second inlet of the first solvent (or second solvent) may be such that, H being the total height of the column, the ratio H3 / H is between 0.05 and 0.4.
[0065] The solvent is preferably aqueous. When there are two solvents, the first is preferably at a neutral pH (between 6.5 and 7.5, possibly containing soluble organic molecules) while the second is acidic (pH less than 6.5, with the addition of acid (for example, an acidic aqueous solution containing 10 ppm and 20% by weight of at least one strong or weak acid, organic or mineral, in particular chosen from at least one of the following acids: acetic acid, nitric acid, sulfuric acid, hydrochloric acid, citric acid, oxalic acid, lactic acid, formic acid, and possibly soluble organic molecules).
[0066] The or at least one of the solvents when there are several may also be an aqueous solution acidified by injecting carbon dioxide into the aqueous solution (which may already contain an acid among those mentioned above). Indeed, the hydrothermal liquefaction step prior to the treatment according to the invention tends to generate carbon dioxide, which can therefore be advantageously used to acidify the solvent(s), if necessary.
[0067] Preferably, contacting step f) comprises dedicated or additional decantation to improve decantation between the two aqueous and organic phases. The decantation device used (e.g., a decanter) may be located after the column (downstream thereof) or after (downstream of) the last liquid-liquid extraction column, when there are several columns) or between two liquid-liquid extraction columns in series that are used in separation step c). The extraction column (or one of those used in step c) may have a short residence time decantation function, which tends to separate the phases in a non-optimal manner, and it is possible that a residual free water fraction (drops) is entrained in the raffinate. In this case, a decanter may be placed downstream (on line 25 detailed later) to better separate the water (and not upstream of the column).If the contact between the two liquid phases is done via two separate columns, then a decanter can be placed between the two columns, or just one at the outlet of the second column (or no decanter).
[0068] Preferably, step f) of contacting the diluted biocrude obtained in step e) is carried out with at least two separate solvents which are brought into contact with said diluted biocrude in separate contacting zones and comprising a first solvent which is an aqueous liquid phase at neutral pH, in particular between 6.5 and 7.5, and a second solvent which is an acidic aqueous liquid phase, having a pH of less than 6.5.
[0069] The invention also relates to a hydrothermal liquefaction installation for a feedstock derived at least in part from biomass, with a view to obtaining a so-called biocrude product, with a reduced content of mineral compounds, in particular metallic ones, which implements the method described above.
[0070] The invention also relates to a hydrothermal liquefaction installation for an initial carbon load at least partly derived from biomass, in order to obtain a so-called biocrude product with a reduced content of mineral compounds, said installation comprising the following devices:
[0071] - a device a) for mixing the initial carbon charge with at least one catalyst and at least one liquid phase, including at least one first aqueous phase containing all or part of the catalyst and optionally at least one first organic phase,
[0072] - a device b) for hydrothermal liquefaction of the mixture obtained with the mixing device a), in order to obtain a liquefaction product,
[0073] - a device c) for liquid / liquid / gas separation of the liquefaction product obtained in step b), in order to obtain a first gaseous phase, a second liquid aqueous phase and a second liquid organic phase called biocrude, (part of which is optionally recycled as an organic phase in the mixing device a))
[0074] - a device d) for separating by heating the second liquid aqueous phase (10) obtained with the liquid / liquid / gas separation device c), in order to obtain a third liquid aqueous phase (12) enriched with minerals originating at least from the catalyst used in the mixing device a) and a first water vapor phase (22),
[0075] - a device e) for diluting the second liquid organic phase (18) called biocrude obtained with the device c) for liquid / liquid / gas separation with a diluent (28) which comprises an organic liquid phase which has a viscosity and a density lower than that of said second liquid organic phase called biocrude, so as to obtain a diluted biocrude (20),
[0076] - a device f) for contacting the diluted biocrude obtained with the dilution device e) with at least one solvent which comprises a liquid aqueous phase, said device comprising a counter-current liquid-liquid extraction column, preferably gravity-driven, so as to obtain, on the one hand, a raffinate comprising the biocrude depleted in mineral compounds and diluent, and on the other hand an extract comprising the solvent enriched in mineral compounds,
[0077] - a device g) for separating the raffinate obtained with the contacting device f), so as to obtain, on the one hand, the biocrude depleted in mineral compounds (27) and on the other hand a phase comprising the diluent),
[0078] - a device h) for condensing a portion of the first vapor phase obtained in step d) and for recycling said portion of the first vapor phase once condensed as a solvent in step f) of contacting,
[0079] - a device i) for at least partial recycling of the extract obtained with the contacting device f) to the heating separation device d)
[0080] - a device j) for separating at least a first part of the first vapor phase (22) obtained with the device d), in order to obtain a fourth aqueous phase (15), and a first so-called light organic phase (2) possibly recycled as an organic phase in the mixing device a).
[0081] We find the devices implementing the steps of the process described above. As already indicated, some of the devices may be common to several steps / several operations.
[0082] The dilution device e) may be a tank-type device fed by both the biocrude feed and the diluent. It may also simply be implemented by a plurality of supply lines that converge toward one or more common lines where the mixing / dilution is done dynamically up to the contacting device, using appropriate valves. The contacting device f) is preferably a gravity counter-current liquid / liquid extraction column. It may be a single column or a plurality of them, mounted in series or in parallel. The column(s) are generally equipped at the top and / or bottom of the column with settling devices, and additional settling tanks may be added at the top outlet (light phase) of each column, their role having been detailed above.
[0083] The installation according to the invention may also comprise a device for recycling at least part of the phase comprising the diluent obtained with the device g) as a diluent for the dilution device e). This recycling device may consist of pipe(s) providing a fluid connection between the two devices g) and f) and controlled in a known manner by valves.
[0084] The installation according to the invention may provide that the contacting device f) comprises a counter-current liquid / liquid extraction column equipped at the bottom of the column and / or at the top of the column with a decantation device f1) f2).
[0085] The installation according to the invention may also comprise a device k) for at least partial recycling of the phase comprising the diluent obtained with the separation device g) as diluent in the dilution step e).
[0086] The installation according to the invention may also comprise a device I) for at least partial recycling of the phase comprising the diluent obtained with the separation device g) in the liquid / liquid / gas separation device c).
[0087] The installation according to the invention may also comprise a device m) for at least partial recycling of the third liquid aqueous phase to the mixing device a).
[0088] The installation according to the invention may also comprise a device for at least partial recycling of the first organic phase and / or the second organic phase (in particular via flow 4 detailed below) to the mixing device a).
[0089] The or at least each of the recycling devices is preferably in the form of pipes or sets of pipes ensuring the appropriate fluid connection to constitute recycling loops which can be controlled in particular using valve systems (alternatively, at least some of these recycles can also provide intermediate storage of the flows to be recycled in tanks).
[0090] Preferably, the device d) for separating by heating the second liquid aqueous phase and / or the separation device g) comprises at least one device chosen from a distillation column, an evaporator, an exchanger followed by a separator flask, in particular a so-called "flash" separator flask. Preferably, the installation comprises a device for recycling at least part of the phase (28) comprising the diluent obtained with the separation device g) as a diluent for the dilution device e).
[0091] Preferably, the contacting device f) comprises a counter-current liquid / liquid extraction column, preferably gravity-fed, and preferably equipped at the bottom of the column and / or at the top of the column with a decantation device f1) and / or f2).
[0092] The invention also relates to a biomass treatment process comprising hydrothermal liquefaction of biomass, then a treatment aimed at reducing the content of mineral compounds in the biocrude obtained, as described above, then a conversion treatment of the treated biocrude of the hydroconversion, hydrotreatment, hydrocracking, catalytic cracking type in order to produce biofuels and / or other chemical compounds (biosourced).
[0093] List of Figures
[0094] Figure 1: This figure very schematically represents an installation implementing the biocrude treatment process according to the invention.
[0095] This figure therefore does not represent all the equipment in the installation, but only those that are most useful for understanding the invention. The various devices and others are not necessarily to scale, nor necessarily represented in space as they might be in an industrial site.
[0096] The list of references is as follows:
[0097] 1 - initial charge including biomass
[0098] 2 - organic phase of light organic compounds from the fractionation (separation) device 14
[0099] 3 - mixture from the mixing device 29
[0100] 4 - phase from the solid / liquid separation device 8 having treated the biocrude from the hydrothermal liquefaction device 5
[0101] 5 - hydrothermal liquefaction device
[0102] 6 - flow from the separation device 11 and intended for purging
[0103] 7 - liquefaction product: effluent from the hydrothermal liquefaction device 5 and feeding the liquid / liquid / gas separation device 8 (mixture of water and biocrude)
[0104] 8 - separation device / liquid / liquid / gas
[0105] 9 - fraction of stream 28 which is a light fraction of the biocrude accumulated in a recycling loop
[0106] 10 - aqueous phase 11 - separation device
[0107] 12 - liquid aqueous phase from the separation device 11
[0108] 13 - vapor phase from vapor phase 22
[0109] 14 - separation device
[0110] 15 - aqueous phase from the separation device 14
[0111] 16 - extract from the liquid-liquid extraction column 21
[0112] 17 - liquid aqueous phase from the vapor phase 22 for injection as solvent (or first solvent when there are several) at the top of the liquid / liquid extraction column 21
[0113] 18 - organic phase from the liquid / liquid / gas separation device 8
[0114] 19 - biocrude from the liquid / liquid / gas separation device 8, corresponding to the phase
[0115] 18 of which a fraction 4 could be removed
[0116] 20 - mixing of biocrude flow 19 and stream 28
[0117] 21 - liquid / liquid extraction column
[0118] 22 - vapor phase from separation device 11
[0119] 23 - optional injection point of a first solvent into the liquid / liquid extraction column 21
[0120] 24 - optional injection point of a second optional solvent into the liquid / liquid extraction column 21
[0121] 25 - raffinate, i.e. organic effluent from the liquid / liquid extraction column 21
[0122] 26 - separation device
[0123] 27 - “demineralized” biocrude, i.e. depleted of mineral compounds
[0124] 28 - a light fraction of biocrude accumulated in a recycling loop
[0125] 29 - mixing device
[0126] 30 - aqueous phase containing one or more catalysts
[0127] 31 - gas phase from the liquid / liquid / gas separation device 8
[0128] Description of the embodiments
[0129] The invention aims to treat by hydrothermal liquefaction loads containing biomass, to obtain liquefied biomass which is also depleted in mineral and metallic compounds.
[0130] As a reminder, the feedstock for hydrothermal liquefaction may be biomass, preferably selected from plants, grasses, trees, wood chips, seeds, fibers, seed coats, aquatic plants, algae, hay and other sources of lignocellulosic materials, such as, for example, those from organic waste, municipal waste, agri-food waste, animal waste, forestry waste, sawmill waste, slaughter residues, agricultural and industrial waste (such as, for example, sugar cane bagasse, waste from oil palm cultivation, sawdust or straw). The feedstock for hydrothermal liquefaction may also come from pulp and by-products of recycled or non-recycled paper, or by-products from paper mills, waste such as used plastics, used tires. The feedstock may also be a mixture of at least two of these materials.
[0131] In the context of the invention, the initial feedstock may be a type of biomass or a mixture of at least two of these types of biomass. It is not excluded that the initial feedstock may also contain a portion of hydrocarbon feedstock which is not of biomass origin, but in this case this portion is preferably (very) minor.
[0132] As a reminder, the characteristics of a biocrude type feedstock after hydrothermal liquefaction of interest in the invention may be as follows: The biocrude obtained by hydrothermal liquefaction is a complex mixture of compounds consisting mainly of hydrocarbons and oxygenated compounds. In general, the oxygenated compounds are organic acids, ketones, oxygenated aromatic compounds, alcohols, aldehydes, esters, ethers and water. Water generally represents less than 15% by weight of the biocrude.
[0133] In the case of a lignocellulosic biomass feedstock, the biocrude contains compounds derived from cellulose, hemicellulose and lignin (structure present in lignocellulosic biomass).
[0134] The biocrude obtained by hydrothermal liquefaction has an oxygen, sulfur and nitrogen content that varies greatly depending on the hydrothermal liquefaction load (algae, wood, etc.). For example, biocrude from hydrothermal liquefaction of wood generally consists of 5 to 20% by weight of oxygen, less than 0.5% by weight of sulfur and less than 5% by weight of nitrogen in the dry biocrude (without water).
[0135] Biocrude can contain up to 4% by weight of inorganics, mainly metals such as sodium, potassium but also calcium, iron, etc. Inorganics can come from the catalysts used for hydrothermal liquefaction, the hydrothermal liquefaction feedstock, and the metals used to grind the hydrothermal liquefaction feedstock. Sodium and potassium can be present in significant quantities in biocrude because the hydrothermal liquefaction process uses alkali-based catalysts (NaOH, KOH, K2CO3, Na2CO3, etc.) in significant quantities.
[0136] Biocrude is generally characterized by a kinematic viscosity at 50°C between 10 and 40,000 cSt, a dynamic viscosity at 50°C between 10 and 40,000 cP, a density at 15°C between 0.9 and 1.2 and a final distillation temperature exceeding 750°C.
[0137] Biocrude has a very wide distillation range, from room temperature to over 750°C. For example, for biocrude from hydrothermal liquefaction of wood, approximately 10% by weight of the biocrude is vaporized in the range 20-180°C, 10% by weight to 45% by weight of the biocrude is vaporized in the range 180-350°C, and 45% by weight to 80% by weight of the biocrude is vaporized above 350°C.
[0138] Figure 1 shows an installation for implementing the invention which will be described below.
[0139] The feedstock to be liquefied feeds the process via stream 1. This feedstock 1 may be biomass preferably selected from plants, grasses, trees, wood chips, seeds, fibers, seed coats, aquatic plants, algae, hay and other sources of lignocellulosic materials, such as, for example, those originating from organic waste, municipal waste, agri-food waste, waste of animal origin, forestry waste, sawmill waste, slaughter residues, agricultural and industrial waste (such as, for example, sugar cane bagasse, waste from oil palm cultivation, sawdust or straw). The feedstock for hydrothermal liquefaction may also originate from paper pulp and by-products of recycled or non-recycled paper or by-products from paper mills, waste such as used plastics, used tires.Load 1 can be a combination of the loads listed previously.
[0140] This process charge 1 is mixed in mixer 29 with streams 2, 30 and 4:
[0141] - Stream 2 consists of light organic compounds and comes from fractionation 14 described below.
[0142] - Stream 30 contains catalysts and chemicals in water and is derived from fractionation 11 described later.
[0143] - Stream 4 is a fraction of the biocrude produced by hydrothermal liquefaction and comes from separator 8 described later.
[0144] Stream 3 from mixer 29 feeds hydrothermal liquefaction section 5, where stream 3 is heated, pressurized, converted and finally cooled to form stream 7.
[0145] The stream 7 feeds a gas-liquid-liquid separator 8. The products leaving the separator 8 are a gas 31, an aqueous phase 10, an organic phase 18 called biocrude, a part 4 of which is recycled to the mixer 29, and the remainder 19 is sent to the liquid-liquid extraction column 21.
[0146] An optional variation of the process (dotted line in the figure) consists of mixing stream 7 with stream 9 which is a fraction of stream 28, a light fraction of the biocrude accumulated in a recycling loop described later, in order to improve the separation in separator 8.
[0147] The aqueous stream 10 undergoes a separation operation 11 by boiling temperature (flash, distillation, evaporation, etc.) to concentrate the catalysts and the chemical products at its liquid outlet 12, which is partly purged by the stream 6 and partly recycled via the stream 30 to the mixer 29.
[0148] The steam outlet 22 from the separation 11 contains substantially no minerals, and it is divided into 2 streams, stream 13 in vapor form and stream 17 in liquid form, obtained by condensation of a fraction of stream 22:
[0149] - Stream 13 is subject to a new separation step 14 by boiling temperature, with the aim of recovering the organic compounds 2 in order to recycle them to the mixer 29. Stream 15 obtained at the bottom of separation 14 contains mainly water.
[0150] - Stream 17, composed mainly of water and water-soluble organics, is used as a solvent to demineralize the biocrude in liquid-liquid extraction column 21.
[0151] Biocrude 19 is mixed with stream 28 to form stream 20 called diluted biocrude.
[0152] Stream 28 is a light fraction of the biocrude, accumulated in a recycling loop described later. This mixing is carried out to reduce the density and viscosity of the biocrude (dilution) and thus make it easier to implement in the gravity liquid-liquid extraction column 21.
[0153] The diluted biocrude 20 feeds the so-called gravity liquid-liquid extraction column 21 at its foot and has a mass flow rate Qm. The column 21 extends along a vertical or essentially vertical longitudinal axis.
[0154] Liquid-liquid extraction is carried out using a solvent 17 consisting of an aqueous solution, originating from the condensation of the steam 22, possibly treated or possibly supplemented by additives. This may be pure water, demineralized water, water with soluble organic molecules, an acidic aqueous solution containing from 10 ppm to 20% by weight of an acid such as acetic acid, nitric acid, sulfuric acid, hydrochloric acid, citric acid, oxalic acid, lactic acid, formic acid or any other acid, or a mixture of these different aqueous solutions.
[0155] The liquid-liquid extraction column 21 is supplied at its bottom by the stream 20.
[0156] The liquid-liquid extraction column 21 is fed at the top by the stream 17 which is an aqueous solvent containing mainly water and water-soluble organic compounds.
[0157] An optional variant of the process consists of injecting another solvent of different composition, in particular an acidic aqueous solvent 24, in an intermediate position along the height of the column 21, in order to improve the extraction of inorganics.
[0158] Another optional variant, if an injection of acidic aqueous solvent 24 is implemented, is to inject a portion of the non-acidic aqueous solvent 17 at the lower position of the column (stream 23). In this case, stream 23 is injected lower than stream 24 in the column.
[0159] The biocrude 19 from the hydrothermal liquefaction unit has a flow rate Qb. The biocrude 19 is mixed with the recycled diluent 28 having a flow rate Qd such that 0.1 < Qd / Qb < 10 and preferably such that 0.5 < Qd / Qb < 3. The flow rates are understood as mass per unit of time.
[0160] The recycled diluent 28 is preferably a compound or a mixture of compounds having a dynamic viscosity at 20°C of less than 4 cP, and generally not less than 0.3 cP, and a density at 15°C of between 600 and 850 kg / m3. The dilution is carried out by providing in the biocrude supply pipe 19 to the extraction column 21 a tapping of a pipe carrying the diluent 28: the mixing between the biocrude and the diluent is carried out in the common pipe portion downstream of the tapping. (“upstream” and “downstream” are understood in the present text by taking into account the progression of the biocrude load in the installation).
[0161] The mixture 20, biocrude + diluent, called “diluted biocrude”, here has a dynamic viscosity at 20°C less than or equal to 7 cP, preferably less than or equal to 4 cP and a density at 15°C less than or equal to 950 kg / m 3 , preferably less than or equal to 900 kg / m 3 , and generally not less than 600 kg / m3 These properties are achieved by choosing an appropriate diluent type and diluent flow rate (relative to the biocrude flow rate).
[0162] The diluent 28 may be a light fraction present in the biocrude (the process may start with an initial diluent, which will gradually be substituted by the recycled phase containing the diluent, as indicated above) or a chemical compound (or a mixture of chemical compounds) present or not in the biocrude. The diluent may consist, for example, of compounds from the family of alcohols, ethers, ketones and hydrocarbons.
[0163] The final boiling point of the diluent 28 is preferably less than or equal to 150°C, and preferably less than or equal to 100°C. It is preferably at least 60°C.
[0164] Solvent 17 feeds column 21 in the upper position (column head) with a flow rate Qs. The flow rate Qs of solvent 17 is chosen such that 0.05 < Qs / Qm < 5 and preferably 0.3 < Qs / Qm < 3.
[0165] The extraction column 21 has the following characteristics:
[0166] - Operating pressure P between 0.5 bar abs (0.5.10 5 Pa) and 15 bar abs (15.10 5 Pa), preferably between 0.9 bar abs (0.9.10 5 Pa) and 1.5 bar abs (1.5.10 5 Pa).
[0167] - Operating temperature T between 15°C and 150°C, preferably between 20°C and 60°C
[0168] - T / S between 5 and 80 m / h, preferably between 10 and 40 m / h, with:
[0169] S the passage section of column 2, in m 2
[0170] T the total volume traffic in column 21, T being defined as follows
[0171] T = Qm / rhom + Qs / rhos, expressed in m 3 / h
[0172] With rhom and rhos the densities, for example in kg / m3, of the diluted biocrude 20 and the solvent 17 in the operating conditions of column 21 (pressure, temperature).
[0173] The useful height of column 21 is between 1.5 m and 50 m high, preferably between 1.8 m and 25 m. The column can be of different types: packed column, perforated tray column, mechanically stirred column, pulsed column or other. In column 21, two phases are mixed and brought into contact: an organic phase (the diluted biocrude 20) and an aqueous phase (solvent 17). In column 21, one phase is dispersed in the other, which is the continuous phase.
[0174] The organic phase is called the light phase because its density is lower than the other phase, the aqueous phase. The aqueous phase is called the heavy phase.
[0175] The dispersed phase can be the heavy phase (solvent 17) or the light phase (diluted biocrude 20), but preferably the light phase (diluted biocrude 20). If the dispersed phase is the heavy phase (solvent 17), the column is preferably equipped with a decanter at its bottom. The decanter will be at the top of the column if the dispersed phase is the light phase (diluted biocrude 20). A decanter can also be provided at the bottom and top of the column.
[0176] Column 21 allows a theoretical number of stages to be reached between 2 and 15, and preferably between 2.5 and 7.
[0177] The effluents from column 21 are:
[0178] - A raffinate 25 consisting mainly of the biocrude, the diluent and the compounds present in the solvent (mainly water). The quantity of inorganic / mineral compounds present in the raffinate 25 is much lower than that in the diluted biocrude 20, due to the efficiency of the liquid-liquid extraction. The organic effluent 25 from the column 21, called raffinate, contains the demineralized diluted biocrude, i.e. having a reduced content of inorganic compounds. This stream 25 feeds a separation operation 26 aimed at separating the demineralized biocrude 27 from a light cut 28, which is recycled to dilute the biocrude before entering the liquid-liquid extraction column 21.
[0179] - An extract 16 consisting mainly of solvent, extracted inorganics, compounds present in the diluted biocrude 20, such as diluent 28 and biocrude 20. The aqueous effluent 16 from column 21, called extract, is an aqueous solution rich in inorganics, the inorganics being used as catalysts for hydrothermal liquefaction. The extract 16 is sent to the separation step 11 to recycle the inorganics to the hydrothermal liquefaction step via stream 30.
[0180] The raffinate 25 feeds a separation device 26 based on the boiling temperature, such as a distillation column, an evaporator, an exchanger followed by a flash separator drum. This device makes it possible to separate a “diluent” 28 (which can be recycled at the inlet of column 21), which consists of a light constituent or a mixture of light constituents, and a demineralized biocrude 27 having a greatly reduced content of inorganics, in particular metals, compared to the biocrude 19.
[0181] The invention achieves a reduction (by weight) in the content of inorganic compounds, such as mineral salts / metal salts, in the biocrude of at least 50% (by weight) and in particular at least 70% (by weight). It is thus possible to achieve biocrude qualities with contents of at most 500 ppm, in particular at most 400 or 300 or 200 or 100 ppm of all these inorganic compounds.
[0182] It can be seen that when the biocrude treatment process to reduce its inorganic / mineral (especially metallic) compound content is integrated into the hydrothermal liquefaction process, it does not consume (or much less) water and the extracted inorganic compounds can be recycled to the hydrothermal liquefaction as catalysts and chemicals. These two advantages make it possible to reduce the overall operating cost of the two processes combined.
[0183] Examples
[0184] Example 1 according to the state of the art
[0185] A hydrothermal liquefaction unit whose characteristics are described below produces a biocrude which is then sent to another site to be demineralized by liquid-liquid extraction.
[0186] The feedstock of the hydrothermal liquefaction unit is wood biomass. The operating conditions of hydrothermal liquefaction are:
[0187] - temperature T: between 200 and 400°C (typically between 350 and 400°C, for example around 375°C)
[0188] - pressure P: between 5 and 400 MPa (generally between 30 and 40 MPa, for example around 35 MPa)
[0189] - alkali cations (e.g. Na+ and K+): introduced as a catalyst and pH adjuster, typical consumption data ranges from 1 to 20 grams of alkali cations per kg of biomass (dry), including 20 g of sodium per kg of woody biomass (dry) and 10 g of potassium per kg of biomass (dry).
[0190] The biocrude obtained at the outlet of the hydrothermal liquefaction unit has a dynamic viscosity at 20°C of 142 cP, a density at 15°C of 985 kg / m 3and contains 912 ppm by weight of sodium Na, 640 ppm by weight of potassium K and 30 ppm by weight of calcium Ca. This biocrude is sent to an inorganic reduction (demineralization) unit located on another site far from the site where the hydrothermal liquefaction takes place.
[0191] In the inorganic reduction unit, the biocrude is diluted with a light fraction of the biocrude having a final boiling point below 150°C, this fraction is obtained by distillation of the diluted biocrude after liquid-liquid extraction. The mass flow rate of biocrude is 200 kg / h and the mass flow rate of the light fraction of biocrude is 200 kg / h.
[0192] The diluted biocrude has a mass flow rate of 400 kg / h, a dynamic viscosity at 20°C of 1.7 cP and a density at 15°C of 890 kg / m 3 .
[0193] The diluted biocrude feeds a stirred countercurrent liquid-liquid extraction column operated at 40°C and 1 atm. The dispersed phase is the light phase (diluted biocrude). The diluted biocrude feeds the liquid-liquid extraction column at its bottom.
[0194] Demineralized water feeds the liquid-liquid extraction column at its head with a flow rate of 200 kg / h.
[0195] The liquid-liquid extraction column has a theoretical number of stages estimated at around 3 under the conditions of use presented.
[0196] The product leaving the bottom of the liquid-liquid extraction column, called extract and rich in inorganics, is sent to a water treatment section before being discharged.
[0197] The product leaving the top of the liquid-liquid extraction column 21, called raffinate 25, is distilled in a distillation column 26. At the top of the distillation column, a light fraction of the biocrude 28 is obtained which is mixed again with fresh biocrude rich in inorganics 19 in order to reduce its density and viscosity before the liquid-liquid extraction.
[0198] At the bottom of distillation column 26, a demineralized biocrude 27 is obtained which contains only 3 ppm by weight of sodium, 1 ppm by weight of potassium and 7 ppm by weight of calcium.
[0199] Water consumption for reducing inorganics in biocrude is 200 kg / h of demineralized water.
[0200] The hydrothermal liquefaction unit consumes 12 kg / h of sodium (Na + ) and 6 kg / h of potassium (K + ) for a production of 200k / h of biocrude. Example 2 according to the invention
[0201] The same hydrothermal liquefaction unit as in Example 1 is used to produce biocrude, but here the inorganic reduction unit is integrated into the hydrothermal liquefaction unit, i.e. the two units are close together and exchange several streams between them.
[0202] The same biocrude as in example 1 is obtained at the outlet of the hydrothermal liquefaction unit.
[0203] The biocrude is diluted with a light fraction of the biocrude having a final boiling point below 150°C, this fraction is obtained by distillation of the diluted biocrude after liquid-liquid extraction. The mass flow rate of biocrude is 200 kg / h and the mass flow rate of the light fraction of biocrude is 200 kg / h.
[0204] The diluted biocrude has a mass flow rate of 400 kg / h, a dynamic viscosity at 20°C of 1.7 cP and a density at 15°C of 890 kg / m 3 .
[0205] The diluted biocrude feeds a stirred countercurrent liquid-liquid extraction column operated at 40°C under 1 atm. The dispersed phase is the light phase (diluted biocrude 20). The diluted biocrude feeds the liquid-liquid extraction column 21 at its bottom.
[0206] The liquid-liquid extraction column 21 is fed at its head with 200 kg / h of aqueous phase obtained by condensation of the vapors from the separator 11 of the hydrothermal liquefaction unit.
[0207] The liquid-liquid extraction column 21 has a theoretical number of stages estimated to be of the order of 3 under the conditions of use presented.
[0208] The product leaving the bottom of the liquid-liquid extraction column 21, called extract 16 and rich in inorganics, is sent to the separator 11 of the hydrothermal liquefaction unit. The inorganics extracted from the biocrude are thus recycled to the hydrothermal liquefaction and thus make it possible to reduce the addition of catalysts and chemical products (in particular Na, K compounds).
[0209] The product leaving the top of the liquid-liquid extraction column, called raffinate 25, is distilled in a distillation column 26. At the top of the distillation column, a light fraction of the biocrude 28 is obtained which is mixed again with fresh biocrude rich in inorganics 19 in order to reduce its density and viscosity before the liquid-liquid extraction in the column 21.
[0210] At the bottom of distillation column 26, a demineralized biocrude 27 is obtained which contains only 3 ppm by weight of sodium, 1 ppm by weight of potassium and 7 ppm by weight of calcium.
[0211] In this example, no water is used to reduce the inorganic compounds in the biocrude and the consumption of sodium and potassium for hydrothermal liquefaction is reduced by 3%. The invention therefore makes it possible to drastically reduce the mineral compound content of the biocrude, while considerably reducing the utility consumption of the overall liquefaction + treatment process.
Claims
Claims 1. Process for the hydrothermal liquefaction of an initial carbonaceous charge (1) at least partly derived from biomass, in order to obtain a product called biocrude with a reduced content of mineral compounds (27), said process comprising the following steps: - step a) of mixing the initial carbon charge (1) with at least one catalyst and at least one liquid phase, including at least one first aqueous phase (30) containing all or part of the catalyst and optionally at least one first organic phase (4,2), - step b) of hydrothermal liquefaction (5) of the mixture (3) obtained in step a), in order to obtain a liquefaction product (7), - step c) of liquid / liquid / gas separation (8) of the liquefaction product (7) obtained in step b), in order to obtain a first gaseous phase (31), a second liquid aqueous phase (10) and a second liquid organic phase (18) called biocrude, - step d) of separation by heating of the second aqueous phase (10) obtained in step c), in order to obtain a third liquid aqueous phase (12) enriched with minerals originating at least from the catalyst used in step a) of mixing, and a first phase of water vapor (22), - step e) of diluting the second liquid organic phase (18) called biocrude obtained in step c) with a diluent (28) which comprises an organic liquid phase which has a viscosity and a density lower than that of said second liquid organic phase called biocrude, so as to obtain a diluted biocrude (20), - a step f) of contacting the diluted biocrude (20) obtained in step e) with at least one solvent (17, 23, 24) which comprises a liquid aqueous phase, with counter-current liquid-liquid extraction, so as to obtain, on the one hand, a raffinate (25) comprising the biocrude depleted in mineral compounds and diluent, and on the other hand an extract (16) comprising the solvent enriched in mineral compounds, - a step g) of separation of the raffinate (25) obtained in step f) of contacting, so as to obtain, on the one hand, the biocrude depleted in mineral compounds (27) and, on the other hand, a phase (9,28) comprising the diluent, - a step h) of condensation of a first part of the first vapor phase (22) obtained in step d) and of recycling said part of the first vapor phase once condensed as solvent (17) in step f) of contacting, - a step i) of at least partial recycling of the extract (16) obtained in step f) of contacting to step d) of separation by heating, - a step j) of separating a second part of the first vapor phase (22) obtained in step d), in order to obtain a fourth aqueous phase (15), and a first so-called light organic phase (2).
2. Method according to the preceding claim, characterized in that the first so-called light organic phase (2) obtained in step j) is at least partly recycled as the first organic phase in the mixing step a).
3. Method according to one of the preceding claims, characterized in that at least part of the second liquid organic phase (18) called biocrude obtained in step c) of liquid / liquid / gas separation is recycled as first organic phase (4) in step a) of mixing, 4. Method according to one of the preceding claims, characterized in that it comprises a step k) of at least partial recycling of the phase comprising the diluent (28) obtained in step g) of separation as diluent in step e) of dilution.
5. Method according to one of the preceding claims, characterized in that it comprises a step I) of at least partial recycling of the phase comprising the diluent (28) obtained in step g) of separation in step c) of liquid / liquid / gas separation (8).
6. Method according to one of the preceding claims, characterized in that it comprises a step m) of at least partial recycling of the third liquid aqueous phase (12) to the mixing step a).
7. Method according to one of the preceding claims, characterized in that step b) of hydrothermal liquefaction comprises heating, at a temperature between 250°C and 450°C under a pressure between 100.10 5Pa and 350.10 5 Pa, in the presence of at least one catalyst containing a pH modifying component and / or an alkali, such as Na or K and / or an alkaline earth such as Ca.
8. Method according to one of the preceding claims, characterized in that, during dilution step e), the diluent (28) has a final boiling temperature of at most 150°C, preferably at most 100°C.
9. Method according to one of the preceding claims, characterized in that, at the end of dilution step e), the diluted biocrude (20) has a dynamic viscosity at 20°C of at most 7 cP, preferably at most 4 cP, and a density at 15°C of at most 950 kg / m 3 , preferably not more than 900 kg / m 3 .
10. Method according to one of the preceding claims, characterized in that, during the dilution step e), the ratio R of the flow rate Qd of the diluent (28) to the flow rate Qb of the biocrude (19) is at most 10, and in particular at least 0.1, the ratio R preferably being between 0.5 and 3.
11. Method according to one of the preceding claims, characterized in that the contacting step f) is carried out at a temperature between 15 and 150°C and lower than the boiling point of the diluent (28) at the contacting pressure, and at a contacting pressure between 0.5.10 5 Pa and 15.10 5 Pa.
12. Method according to one of the preceding claims, characterized in that step d) of separation and / or step g) of separation and / or step (j) of fractionation is a treatment comprising at least one evaporation, one distillation, one heating followed by one separation.
13. Method according to one of the preceding claims, characterized in that the diluent (28) used in dilution step e) is chosen from a light cut present in the biocrude load or a chemical compound or mixture of chemical compounds, in particular from the family of alcohols, ethers, ketones and hydrocarbons.
14. Method according to one of the preceding claims, characterized in that the solvent (17, 23, 24) used in contacting step f) is chosen from at least one of the following solutions: a pure aqueous solution, a demineralized aqueous solution, an aqueous solution containing soluble organic compounds, an acidic aqueous solution.
15. Method according to one of the preceding claims, characterized in that the contacting step f) is followed by a decantation step f1) and / or f2).
16. Method according to one of the preceding claims, characterized in that step f) of contacting the diluted biocrude (20) obtained in step e) is carried out with at least two separate solvents (24, 17) which are brought into contact with said diluted biocrude (20) in separate contacting zones and comprising a first solvent which is an aqueous liquid phase at neutral pH, in particular between 6.5 and 7.5, and a second solvent which is an acidic aqueous liquid phase, having a pH lower than 6.
5.
17. Installation for hydrothermal liquefaction of an initial carbon load at least partly derived from biomass, in order to obtain a product called biocrude with a reduced content of mineral compounds (27), said installation comprising the following devices: - a device a) for mixing the initial carbon charge (1) with at least one catalyst and at least one liquid phase, including at least one first aqueous phase (30) containing all or part of the catalyst and optionally at least one first organic phase (4,2), - a device b) for hydrothermal liquefaction of the mixture (3) obtained with the mixing device a), in order to obtain a liquefaction product (7), - a device c) for liquid / liquid / gas separation of the liquefaction product (7) obtained in step b), in order to obtain a first gaseous phase (31), a second aqueous phase liquid (10) and a second liquid organic phase (18) called biocrude, a part (4) of which is optionally recycled as organic phase in the mixing device a), - a device d) for separating by heating the second liquid aqueous phase (10) obtained with the liquid / liquid / gas separation device c), in order to obtain a third liquid aqueous phase (12) enriched with minerals originating at least from the catalyst used in the mixing device a) and a first water vapor phase (22), - a device e) for diluting the second liquid organic phase (18) called biocrude obtained with the device c) for liquid / liquid / gas separation with a diluent (28) which comprises an organic liquid phase which has a viscosity and a density lower than that of said second liquid organic phase called biocrude, so as to obtain a diluted biocrude (20), - a device f) for contacting the diluted biocrude (20) obtained with the device e) for dilution with at least one solvent (17, 24) which comprises a liquid aqueous phase, said device comprising a counter-current liquid-liquid extraction column (21), preferably gravity-driven, so as to obtain, on the one hand, a raffinate (25) comprising the biocrude depleted in mineral compounds and diluent, and on the other hand an extract (16) comprising the solvent enriched in mineral compounds, - a device g) for separating the raffinate (25) obtained with the contacting device f), so as to obtain, on the one hand, the biocrude depleted in mineral compounds (27) and on the other hand a phase comprising the diluent 28), - a device h) for condensing a portion of the first vapor phase (22) obtained in step d) and for recycling said portion of the first vapor phase once condensed as solvent (17) in step f) of contacting, - a device i) for at least partial recycling of the extract (16) obtained with the contacting device f) to the heating separation device d), - a device j) for separating at least a second part of the first vapor phase (22) obtained in step d), in order to obtain a fourth aqueous phase (15), and a first so-called light organic phase (2) possibly recycled as an organic phase in the mixing device a).
18. Installation according to the preceding claim, characterized in that it comprises a device k) for at least partial recycling of the phase comprising the diluent (28) obtained with the separation device g) as diluent in the dilution step e).
19. Installation according to one of claims 17 or 18, characterized in that it comprises a device I) for at least partial recycling of the phase comprising the diluent (9) obtained with the separation device g) in the liquid / liquid / gas separation device c) (8).
20. Installation according to one of claims 17 to 19, characterized in that it comprises a device m) for at least partial recycling of the third liquid aqueous phase (12) to the mixing device a).
21. Installation according to one of claims 17 to 20, characterized in that the device d) for separation (11) by heating the second liquid aqueous phase (10) and / or the device g) for separation (26) and / or the device j) for separation comprises at least one device chosen from a distillation column, an evaporator, an exchanger followed by a separator flask, in particular a so-called “flash” separator flask.
22. Installation according to one of claims 17 to 21, characterized in that it comprises a device for recycling at least part of the phase (28) comprising the diluent obtained with the separation device g) as diluent for the dilution device e).
23. Installation according to one of claims 17 to 22, characterized in that the contacting device f) comprises a counter-current liquid / liquid extraction column (21), preferably gravity-fed, and preferably equipped at the bottom of the column and / or at the top of the column with a decantation device f1) and / or f2).