Conversion of biomass-derived hydrocarbon feedstocks to acrylates

Abstract

The invention relates to a method and an apparatus for converting biomass to acrylate. The method comprises, in order: a) a step of treating biomass to produce ethanol and CO2; b) a step of dehydrating the ethanol obtained at the end of step a) to obtain ethylene; c) a step of synthesizing an acrylate from the ethylene obtained at the end of step b) and the CO2 obtained at the end of step a).

Description

Field of the Invention

[0001] The present invention relates to a method for processing biomass, preferably lignocellulosic biomass, to produce acrylate from a single biobased carbon source while maximizing carbon yield.

[0002] The lignocellulosic biomass fermentation process can produce ethanol and CO2, which can be advantageously converted into acrylate compared to the prior art. Prior Art

[0003] Acrylates are derivatives of acrylic acid and are used, in particular together with acrylic acid, for the preparation of superabsorbent polymers. It is known to those skilled in the art that acrylates can be synthesized from acrylic acid by adding a base, just as acrylic acid can be synthesized from acrylates by adding an acid.

[0004] Currently, acrylic acid is industrially produced by the oxidation of propylene in the presence of a heterogeneous catalyst at high temperature. However, the price of propylene is relatively high and has a significant impact on the price of acrylic acid, and several methods for synthesizing acrylic acid have been developed, especially those using carbon monoxide as a raw material. Patent US 3,023,237 relates to the Reppe process, which allows the synthesis of acrylic acid from acetylene and carbon monoxide. Although this method has been industrialized, the synthesis of acrylic acid by propylene oxidation still remains more economically viable.

[0005] Another alternative being explored is the synthesis of acrylic acid or its derivatives from carbon dioxide (CO2). CO2 has the advantage of being inexpensive, and upgrading it in the form of high-value-added products is an attractive way to reduce its environmental impact. Patent application US 2016 / 016,876 discloses a method for producing acrylic acid by generating lactone from ethylene oxide and carbon monoxide. In certain embodiments, the step of generating lactone is carried out in the presence of ethylene oxide and CO2.

[0006] Another method is that patent application US 2018 / 057,439 proposes using CO2 as a precursor to carbon monoxide in the case of the above-mentioned Reppe process.

[0007] Finally, another alternative is to directly use CO2 without going through the carbon monoxide reduction process. There are many documents dealing with the synthesis of carboxylic acids or carboxylates from CO2 and olefins, especially ethylene. By way of example, mention may be made of WO 2019 / 053541, WO 2019 / 053,540, WO 2015 / 173,296, CN104418737 or CN105622400.

[0008] Ethylene can be produced from fossil resources through steam cracking processes or through the dehydration of bioethanol. It is well known that bioethanol can be produced by fermenting sugars from various biomass sources. However, the fermentation production of ethanol generally does not have a good "carbon" yield because part of the carbon is lost in the form of CO2. In addition, ethanol produced from "first-generation" (1G) biomass competes with the agricultural food industry, and the significant loss of this resource in the form of greenhouse gases is even more problematic.

[0009] Finally, there are other methods for synthesizing acrylic acid from lignocellulosic biomass, particularly through the synthesis of lactic acid. Different from the above methods, these methods do not use CO2 or ethylene. The step of converting biomass into lactic acid generally does not produce CO2, but the step of dehydrating lactic acid to acrylic acid is not straightforward.

[0010] Therefore, the present invention aims to overcome all of the above disadvantages. More precisely, the object of the present invention is to develop a method for treating biomass (preferably "second-generation" (2G) lignocellulosic biomass) to produce acrylate from ethanol and CO2 generated by fermentation.

[0011] Object of the Invention In the foregoing, the first object of the present specification is to overcome the problems existing in the prior art and upgrade carbon (and in particular bio-based carbon in the form of CO2) to high-value-added compounds, and in particular acrylate. Specifically, the present invention relates to a method for producing acrylate according to a step arrangement, which method converts biomass into ethanol and CO2, and then converts these products into acrylate. In addition to or instead of certain steps in conventional acrylate synthesis, the method also employs one or more of the following steps.

[0012] According to a first aspect, the present invention relates to a method for converting biomass into acrylate, which successively comprises: a) a step of treating biomass to produce ethanol and carbon dioxide; b) a step of dehydrating the ethanol obtained at the end of step a) to obtain ethylene; c) a step of synthesizing acrylate from the ethylene obtained at the end of step b) and the carbon dioxide obtained at the end of step a) in the presence of a catalytic precursor and a solvent.

[0013] The present invention is based on the upgrading of the by-product CO2 generated during the step of fermenting biomass to produce ethanol, and the water generated during the dehydration step may be reused in other steps of the method according to the present invention. Therefore, the present invention has a series of unit operations aimed at maximizing the carbon yield of synthesizing acrylate from biomass (preferably lignocellulosic biomass, and even more preferably "second-generation" (2G) lignocellulosic biomass).

[0014] According to one or more embodiments, step a) includes the following sub-steps: a1) a step of pre-treating biomass to obtain a pre-treated substrate; a2) a step of subjecting the pre-treated substrate obtained at the end of step a1) to enzymatic hydrolysis or chemical hydrolysis to obtain an enzymatic hydrolysis or chemical hydrolysis slurry; a3) a step of subjecting the enzymatic hydrolysis or chemical hydrolysis slurry obtained at the end of step a2) to ethanol fermentation to obtain ethanol and carbon dioxide.

[0015] According to one or more embodiments, sub-step a1) is carried out by steam explosion under acidic conditions at a temperature between 150°C and 250°C for a period of 5 minutes to 30 minutes.

[0016] According to one or more embodiments, sub-step a2) is carried out by enzymatic hydrolysis in the presence of Trichoderma reesei cellulase.

[0017] According to one or more embodiments, when step a2) is enzymatic hydrolysis, steps a2) and a3) are carried out simultaneously.

[0018] According to one or more embodiments, step b) includes the following sub-steps: b1) a step of evaporating an evaporation feedstock containing ethanol obtained at the end of step a) in a heat exchanger, the evaporation feedstock being introduced into the evaporation step at a pressure between 0.1 MPa and 2.5 MPa to produce an evaporated feedstock; b2) a step of superheating the evaporated feedstock obtained at the end of step b1) so that the evaporated feedstock reaches an inlet temperature suitable for the dehydration reaction temperature; b3) a step of dehydrating the feedstock obtained in step b2) in at least one adiabatic reactor containing at least one dehydration catalyst, and the dehydration reaction occurs in the adiabatic reactor, the adiabatic reactor operating at an inlet temperature of 350°C to 550°C and an inlet pressure of 0.3 MPa to 1.8 MPa.

[0019] According to one or more embodiments, step c) is carried out at a temperature between 105°C and 170°C and at a pressure between 1 MPa and 10 MPa.

[0020] According to one or more embodiments, step c) is carried out in the presence of a base selected from alkoxides of secondary or tertiary alcohols.

[0021] According to one or more embodiments, step c) is carried out in the presence of a catalytic precursor of a metal complex based on a transition metal selected from nickel(0) and palladium(0) complexes.

[0022] According to one or more embodiments, step c) is carried out in the presence of a solvent selected from anisole, cyclohexylpyrrolidone, N,N-dibutylformamide and dimethylacetamide.

[0023] According to one or more embodiments, the method further comprises step d) of performing a liquid-liquid separation of the acrylate in the presence of a back-extraction solvent that is immiscible with the solvent used in step c).

[0024] According to one or more embodiments, the back-extraction solvent is water that is at least partially produced by the ethanol dehydration step b).

[0025] According to one or more embodiments, the biomass is lignocellulosic biomass.

[0026] According to a second aspect, the invention relates to a device for converting biomass into acrylate, the device being capable of performing the method according to the invention, the device comprising: - a first reaction section for producing ethanol and carbon dioxide from biomass; - a second reaction section for dehydrating ethanol into ethylene; and - a third reaction section for producing acrylate from ethylene and carbon dioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram showing an embodiment of the method and device according to the invention for producing acrylate from biomass (preferably lignocellulosic biomass).

[0028] DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENTS Embodiments of the method according to the first aspect of the invention and the device according to the second aspect of the invention will now be described in detail. In the following detailed description, many specific details are disclosed in order to provide a deeper understanding of the method and device. However, it will be apparent to those skilled in the art that the method and device can be used without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.

[0029] Definition In the present application, the terms "comprising", "including", and "containing" are synonymous (have the same meaning) and are inclusive or open-ended and do not exclude other unstated elements. It should be understood that the term "comprising" includes the exclusive and closed term "consisting of". Further, in the present specification, an effluent substantially comprising or only comprising compound A corresponds to an effluent containing at least 90% by weight, preferably at least 95% by weight, and very preferably at least 99% by weight of compound A.

[0030] In the present patent application, the groups of chemical elements are by default given according to the CAS classification (CRC Handbook of Chemistry and Physics, published by CRC Press, edited by D.R. Lide, 81st edition, 2000 - 2001). For example, Group VIII (or Group VIIIB) according to the CAS classification corresponds to the metals in columns 8, 9, and 10 according to the new IUPAC classification; Group VIB according to the CAS classification corresponds to the metals in column 6 according to the new IUPAC classification.

[0031] In the present patent application, "biomass" means any raw material obtained by biological methods, preferably obtained by fermentation of sugars, such as sugars derived from sugar-producing crops like sugarcane (saccharose, glucose, fructose, and sucrose), derived from sugar beet roots, or derived from starchy plants (starch) or derived from lignocellulosic biomass or derived from hydrolyzed cellulose (glucose (mainly) and xylose, galactose), which contains variable amounts of water. Biomass is preferably lignocellulosic biomass, and even more preferably "second-generation" (2G) lignocellulosic biomass.

[0032] Detailed description The present invention can be defined as a method comprising a series of reaction steps that enable the production of acrylate from biomass, preferably lignocellulosic biomass, and even more preferably "second-generation" lignocellulosic biomass (2G). More specifically, the present invention relates to a method for converting biomass into acrylate, which sequentially includes: a) A step of treating biomass, preferably lignocellulosic biomass, to produce ethanol and carbon dioxide (CO2); b) A step of dehydrating the ethanol obtained at the end of step a) to obtain ethylene; c) A step of synthesizing acrylate from the ethylene obtained at the end of step b) and the CO2 obtained at the end of step a).

[0033] In addition, the present invention can also be defined as a device suitable for implementing the method according to the present invention, as Figure 1 shown, which device particularly includes: - The first reaction stage 2 produces ethanol 3 and CO₂ 4 from biomass 1; - The second reaction stage 5 is for dehydrating ethanol 3 to ethylene 6; and - The third reaction stage 7 is for producing acrylate 8 from ethylene 6 and CO₂ 4.

[0034] First reaction stage (step a) of the process according to the invention) The first reaction stage 2 produces ethanol 3 and CO₂ 4 from biomass 1.

[0035] In one embodiment according to the present invention, the biomass used in the method is lignocellulosic biomass, preferably "second-generation" lignocellulosic biomass. Hardwoods and cereal straws are the most commonly used substrates. They mostly consist of about 40% to 50% cellulose, 20% to 25% hemicellulose, and 15% to 25% lignin. Other resources, dedicated forestry crops, residues from alcohol, sugar, and cereal production plants, residues from the paper industry, and products resulting from the processing of cellulose-based and lignocellulosic materials, can all be used.

[0036] In one embodiment according to the present invention, the method for converting biomass into ethanol more particularly includes the following sub-steps: a1) A step of pretreating the biomass, preferably lignocellulosic biomass, to obtain a pretreated substrate; a2) A step of subjecting the pretreated substrate obtained at the end of step a1) to enzymatic hydrolysis or chemical hydrolysis to obtain an enzymatic hydrolysis or chemical hydrolysis slurry; a3) A step of subjecting the enzymatic hydrolysis or chemical hydrolysis slurry obtained at the end of step a2) to ethanol fermentation to obtain ethanol and CO₂.

[0037] Physicochemical pretreatment (step a1)) The pretreatment step a1) enables the production of a pretreated substrate that contains sugars in monomeric form contained in hemicellulose, mainly pentoses such as xylose and arabinose, and hexoses such as galactose, mannose, and glucose, and can improve the accessibility of cellulose embedded in the lignin and hemicellulose matrix. Many techniques are available, including acid cooking, alkaline cooking, steam explosion, and organic solvent pulping treatments. The efficiency of pretreatment is measured by the hemicellulose recovery rate and by the sensitivity of the cellulose residues to hydrolysis. Acid pretreatment under mild conditions and by steam explosion is the most suitable because they can achieve complete recovery of pentoses and good accessibility of cellulose to hydrolysis.

[0038] Preferably, the pretreatment step a1) is carried out by steam explosion under acidic conditions at a temperature advantageously between 150 °C and 250 °C and for a time advantageously between 5 and 30 minutes. In this embodiment, step a1) enables the conversion of hemicellulose into monomers while minimizing losses, in particular the loss of furfural, with xylose being the main sugar. The released sugars are then extracted by washing in the aqueous phase. The solid residue obtained at the end of the extraction (i.e., the pretreated substrate, also referred to herein as the cellulose-based residue) then contains only cellulose and lignin.

[0039] Enzymatic or chemical hydrolysis (step a2)) Subsequently, the pretreated substrate obtained at the end of step a1) is hydrolyzed by an acid process (i.e., a chemical process) or by an enzymatic process using cellulolytic and / or hemicellulolytic enzymes. Microorganisms, such as fungi belonging to the genera Trichoderma, Aspergillus, Penicillium or Schizophyllum, or anaerobic bacteria belonging to, for example, the genus Clostridium, produce these enzymes, which particularly contain cellulases and xylanases and are suitable for the complete hydrolysis of the polymers constituting plants.

[0040] The acidic route using strong acids, and more particularly sulfuric acid, is effective but requires large amounts of chemical products (acids and subsequent bases for neutralization). Enzymatic hydrolysis does not have this drawback; moreover, enzymatic hydrolysis is carried out under mild conditions and is effective.

[0041] In a preferred manner, the pretreated substrate releasing or not releasing the hydrolyzed hemicellulose fraction and, where appropriate, lignin is hydrolyzed using cellulolytic and / or hemicellulolytic enzymes produced by specialized strains, and Trichoderma reesei is the most effective and most suitable for producing cellulases when the carbon substrate is derived from cellulose or lignocellulosic biomass. Preferably, the pretreated substrate to be hydrolyzed is suspended in the aqueous phase at a ratio of 6% to 25%, preferably 10% to 20% dry matter, the pH is adjusted between 4 and 5.5, preferably between 4.8 and 5.2, and the temperature is adjusted between 40 °C and 60 °C, preferably between 45 °C and 50 °C. The hydrolysis reaction is started by adding cellulases; the amounts commonly used are 10 mg to 30 mg of secreted protein per gram of pretreated substrate. The reaction generally lasts from 15 hours to 48 hours, depending on the efficiency of the pretreatment, the composition of the cellulase mixture and the amount of enzyme added. The reaction is monitored by measuring the released sugars (in particular glucose). The sugar solution (slurry) is then separated from the unhydrolyzed solid fraction consisting essentially of lignin by filtration or centrifugation; this slurry is used for ethanol fermentation. When the cellulose fraction has released the hydrolyzed hemicellulose during the treatment step, glucose is the main sugar contained in the slurry.

[0042] Fermentation (step a3)) Ethanol fermentation is a biochemical process in which sugars (carbohydrates, mainly glucose) contained in a slurry are converted into alcohol, preferably ethanol, in a liquid medium without air (anaerobic). The steps for fermenting sugars to obtain ethanol are well known to those skilled in the art.

[0043] Ethanol fermentation is preferably carried out at a temperature between 25°C and 32°C. For a more complete description of traditional fermentation methods, reference can be made to the work “Les Biocarburants, État des lieux, perspectives et enjeux du développement [Biofuels, current state, perspectives and development challenges]”, Daniel Ballerini, published by Technip, 2006.

[0044] Generally, ethanol is separated from the fermentation slurry by distillation, and the residue consists of stillage. Periodic or continuous distillation of ethanol is necessary because above 14% ethanol, certain yeasts can be “poisoned”, resulting in loss of productivity. Distillation is carried out in order to be able to produce an ethanol feedstock suitable for the dehydration methods described subsequently.

[0045] CO2 is recovered in gaseous form at the outlet of the fermenter. According to a basic aspect of the invention, at least part of the CO2 obtained at the end of the fermentation step is sent to the acrylate synthesis step (step c) of the method according to the invention). The CO2 can be compressed by means of a compressor before storage or before use.

[0046] The ethanol fermentation residue, after separation from ethanol, can be used as an inducing carbon source or as the main carbon source for the production of enzymes. Preferably, the concentration of this residue is adjusted to obtain a carbon source concentration most suitable for the production method of cellulolytic and / or hemicellulolytic enzymes.

[0047] The enzymatic hydrolysis and fermentation steps can be carried out simultaneously (simultaneous saccharification and fermentation (SSF) method), and are then advantageously followed by a step of distilling and separating the alcohol obtained.

[0048] Second reaction stage (step b) of the process according to the invention) The second reaction section 5 allows the production of ethylene 6 from the ethanol 3 obtained from the first reaction section 2 (see Figure 1).

[0049] The second reaction section dehydrates the ethanol obtained at the end of step a) of the method according to the invention to form ethylene. Ethanol dehydration is a method known to those skilled in the art, but can be optimized to reduce the energy cost of this method, as described in patent application US 2013 / 190 547.

[0050] Advantageously, the ethanol feedstock used in step b) of the process according to the invention is a concentrated aqueous ethanol feedstock. The term "concentrated aqueous ethanol feedstock" means an ethanol feedstock having an ethanol mass percentage greater than or equal to 35% by weight. Preferably, the concentrated ethanol feedstock comprises an ethanol mass percentage of 35% to 99.9% by weight relative to the total weight of the feedstock. Preferably, the concentrated ethanol feedstock comprises an ethanol mass percentage of 35% to 96% by weight relative to the total weight of the feedstock. The concentrated ethanol feedstock advantageously contains less than 10% by weight, and preferably less than 5% by weight, of alcohols other than ethanol, such as methanol, butanol and / or isoamyl alcohol, advantageously less than 1% by weight of oxygenated compounds other than alcohols, such as ethers, acids, ketones, aldehydes and / or esters, and advantageously less than 0.5% by weight of organic and inorganic nitrogen and sulfur, the weight percentages being expressed relative to the total mass of the feedstock.

[0051] In one embodiment according to the invention, step b) comprises the following sub-steps: b1) evaporating in a heat exchanger the vaporizable feedstock containing ethanol obtained at the end of step a), the vaporizable feedstock being introduced into said evaporation step at a pressure between 0.1 MPa and 2.5 MPa to produce a vaporized feedstock; b2) superheating the vaporized feedstock obtained at the end of step b1) to bring it to an inlet temperature adapted to the dehydration reaction temperature; b3) dehydrating the feedstock obtained in step b2) in at least one adiabatic reactor containing at least one dehydration catalyst, and the dehydration reaction taking place in said adiabatic reactor, said adiabatic reactor operating at an inlet temperature of 350 °C to 550 °C and an inlet pressure of 0.3 MPa to 1.8 MPa.

[0052] The ethanol feedstock used in the case of step b) of the process according to the invention is advantageously subjected to a pre-treatment step before the step b1) of evaporating the feedstock. This pre-treatment step can remove the impurities contained in the feedstock, thus limiting the deactivation of the dehydration catalyst placed downstream, and said impurities are in particular nitrogen-containing compounds and sulfur-containing compounds. The oxygenated compounds present in the feedstock are substantially not removed.

[0053] The said pretreatment step of the ethanol feedstock is advantageously carried out by methods known to those skilled in the art, such as using at least one resin, preferably adsorbing impurities onto a solid at a temperature of 20°C to 60°C; the process includes: a first step of hydrogenolysis, operating at a temperature of 20°C to 80°C; subsequent steps of absorption onto an acidic solid at a temperature of 20°C to 80°C, and / or distillation. In the case of using at least one resin, the resin is preferably an acidic resin and is used at a high temperature of 70°C to 200°C. An alkaline resin may optionally be added before the said resin.

[0054] In the case where the pretreatment step is carried out by adsorbing impurities onto a solid, the solid is advantageously selected from molecular sieves, activated carbon, alumina and zeolites.

[0055] The said pretreatment step of the ethanol feedstock enables the production of a purified ethanol fraction in which organic impurities have been removed, thereby obtaining a purified feedstock that meets the impurity level compatible with the dehydration catalyst.

[0056] Evaporation of the feedstock (step b1) At least part of the feedstock containing optionally pretreated ethanol obtained at the end of step a) of the method according to the invention is called the vaporized feedstock. The vaporized feedstock advantageously also contains a water stream recycled according to cycle step b5) or a water stream external to the method. In this case, the mass ratio of the water stream (whether recycled water stream or water stream external to the method) to the pretreated ethanol stream is advantageously between 1 and 4, for the purpose of reducing the ethanol partial pressure in one or more dehydration reactors and increasing the selectivity of the method in terms of ethylene.

[0057] According to one embodiment of the invention, the method includes step b1), vaporizing the said vaporized feedstock, thereby generating a vaporized feedstock. The vaporization is carried out by heat exchange with a heat source in a heat exchanger, and the heat source can be a stream internal or external to the method, or can be carried out by direct heating (such as in a furnace) or any other technique known to those skilled in the art.

[0058] The vaporized feedstock is introduced into the vaporization step b1) at a pressure of 0.1 MPa to 2.5 MPa and an inlet temperature of 350°C to 500°C.

[0059] Optional compression step In a preferred embodiment, the evaporated feedstock is compressed in a compression step, thereby producing a compressed feedstock. The compression step is preferably carried out in any type of compressor known to those skilled in the art. Specifically, the compression step is advantageously carried out in a compressor of the radial compressor type with an integrated gearbox, or a compressor comprising one or more blowers with radially connected impellers in series without intermediate cooling, or a positive displacement compressor with or without lubrication.

[0060] An optional compression step allows the formation of a heat pump integrated into the process, using streams from the process, allowing the evaporated feedstock from step b1) to be vaporized by heat exchange with the effluent from the dehydration step b3).

[0061] In the case where the optional compression step is carried out, the evaporated feedstock is introduced into the evaporation step b1) at a pressure of 0.1 MPa to 1.4 MPa, preferably 0.2 MPa to 0.6 MPa.

[0062] At the end of the optional compression step, the compression pressure of the feedstock is advantageously 0.3 MPa to 1.8 MPa, preferably 0.5 MPa to 1.3 MPa. The outlet pressure of the feedstock is high enough to ensure that the condensation temperature of the effluent from the last reactor is higher than the evaporation temperature of the feedstock entering step b1), which is a necessary condition for the feasibility of step b1).

[0063] Superheating step b2) The evaporated feedstock (optionally compressed) can be heated in a single-phase gas exchanger by heat exchange with any stream inside or outside the process, preferably by heat exchange with the effluent from the last adiabatic reactor in step b3). In the single-phase gas exchanger, the feedstock (optionally compressed) is superheated. In the case of heat exchange with the gaseous effluent from the last adiabatic reactor in step b3), the latter is "cooled (superheated)" without condensation.

[0064] In the case where the optional compression step is carried out, the single-phase gas exchanger is an exchanger using techniques known to those skilled in the art, which can minimize the pressure drop while having a large exchange surface area. This gas / gas exchange at low pressure results in a low heat flux density through the exchanger wall (lower transfer coefficient), so a large exchange surface area is required. In addition, the pressure loss must be minimized to limit the load on the compressor in the optional compression step. For example, the exchanger can be a pressurized plate exchanger in a calender, provided by Alphalaval®, model Packinox®.

[0065] The evaporated raw material, optionally compressed, optionally heated in the single-phase gas exchanger, and then introduced into an overheating device, preferably a furnace, to reach an inlet temperature compatible with the dehydration reaction temperature in at least one adiabatic reactor.

[0066] Dehydration step b3) According to an embodiment of the present invention, the raw material obtained in step b2) undergoes a dehydration step b3) in at least one adiabatic reactor, which accommodates at least one fixed bed of dehydration catalyst, and the dehydration reaction occurs therein.

[0067] The dehydration step b3) is advantageously carried out in one or two reactors.

[0068] In the case where step b3) is carried out in a single adiabatic reactor, it is advantageous to introduce the compressed and optionally heated raw material at an inlet temperature between 350°C and 550°C, preferably between 400°C and 500°C, and at an inlet pressure between 0.3 MPa and 1.8 MPa, preferably between 0.4 MPa and 0.8 MPa, into the reactor.

[0069] The effluent of the adiabatic reactor in step b3) advantageously has a temperature between 270°C and 450°C, preferably between 340°C and 430°C, and an outlet pressure between 0.2 MPa and 1.6 MPa, preferably between 0.3 MPa and 0.8 MPa.

[0070] In the case where step b3) is carried out in two adiabatic reactors, it is advantageous to introduce the compressed and optionally heated raw material into the first reactor, with an inlet temperature between 350°C and 550°C, preferably between 370°C and 500°C, and an inlet pressure between 0.3 MPa and 1.8 MPa, preferably between 0.4 MPa and 1.1 MPa.

[0071] The effluent from the first adiabatic reactor advantageously leaves the first reactor at a temperature between 270°C and 450°C, preferably between 290°C and 390°C, and at a pressure between 0.3 MPa and 1.7 MPa, preferably between 0.3 MPa and 1.0 MPa.

[0072] Then, preferably, the effluent is placed in a furnace such that the inlet temperature of the effluent entering the second adiabatic reactor is between 350°C and 550°C, preferably between 400°C and 500°C. The pressure at which the effluent enters the second reactor is advantageously between 0.3 MPa and 1.7 MPa, preferably between 0.3 MPa and 0.9 MPa.

[0073] The temperature of the effluent from the second adiabatic reactor when it leaves the second adiabatic reactor is advantageously from 270 °C to 450 °C, and preferably from 340 °C to 430 °C. The outlet pressure of the effluent from the second adiabatic reactor is advantageously from 0.2 MPa to 1.6 MPa, and preferably from 0.3 MPa to 0.8 MPa.

[0074] The inlet temperature of one or more reactors can be advantageously increased gradually to avoid deactivation of the dehydration catalyst.

[0075] In method step b3), the dehydration reaction carried out in at least one adiabatic reactor is advantageously carried out at a weight hourly space velocity (WHSV) of from 0.1 to 20 h -1 and preferably from 0.5 to 15 h -1 The weight hourly space velocity is defined as the ratio of the mass flow rate of the pure ethanol feedstock to the mass of the catalyst.

[0076] The dehydration catalyst used in step b3) is a catalyst well known to those skilled in the art.

[0077] The catalyst can be an amorphous acid catalyst, a zeolite acid catalyst, a silica-alumina-based catalyst, an alumina-based catalyst or a silica-alumina-based catalyst.

[0078] The catalyst is preferably an amorphous acid catalyst or a zeolite acid catalyst.

[0079] In the case where the dehydration catalyst used in step b3) is a zeolite catalyst, the catalyst comprises at least one zeolite selected from zeolites having a pore size of at least 8, 10 or 12 oxygen atoms (8MR, 10MR or 12MR). Specifically, the size of the known zeolite pore diameter is defined by the number of oxygen atoms in the ring-shaped cross-section (referred to as the "molecular ring" or MR) that forms the zeolite channel. Preferably, the zeolite dehydration catalyst comprises at least one zeolite selected from the zeolite structural types of MFI, FAU, MOR, FER, SAPO, TON, CHA, EUO MEL and BEA. Preferably, the zeolite dehydration catalyst comprises a zeolite of the MFI structural type, and preferably ZSM-5 zeolite.

[0080] The zeolite used in the dehydration catalyst used in step b3) of the process according to the invention can be advantageously modified by dealumination or desilication according to any dealumination or desilication method known to those skilled in the art.

[0081] The zeolite used in the dehydration catalyst in method step b3) or the final catalyst can advantageously be modified with a reagent having properties that weaken its overall acidity and improve its hydrothermal stability. Preferably, the zeolite or the catalyst advantageously contains phosphorus, preferably added in the form of H3PO4, and is then subjected to steam treatment after neutralizing the excess acid with a basic precursor (such as calcium). Preferably, the phosphorus content of the zeolite is from 1% to 4.5% by weight, preferably from 1.5% to 3.1% by weight, relative to the total mass of the catalyst.

[0082] Preferably, the dehydration catalyst used in step b3) is the catalyst described in patent applications WO 2009 / 098 262, WO 2009 / 098267, WO 2009 / 098 268 or WO 2009 / 098 269.

[0083] In the case where the dehydration catalyst used in step b3) is an amorphous acid catalyst, the catalyst comprises at least one porous high-temperature resistant oxide selected from alumina, alumina activated by deposition of a mineral acid, and silica-alumina.

[0084] The amorphous or zeolite dehydration catalyst used in step b3) can also advantageously comprise at least one oxide-type matrix (also called a binder). According to the present invention, the term "matrix" means an amorphous or crystalline matrix, or a matrix comprising amorphous and crystalline parts. The matrix is advantageously selected from the elements of clay (such as from natural clays, such as kaolin or bentonite), magnesia, alumina, silica, silica-alumina, aluminate, titanium oxide, boron oxide, zirconium oxide, aluminum phosphate, titanium phosphate, zirconium phosphate, and charcoal, used alone or in mixture. Preferably, the matrix is selected from the elements of alumina, silica, and clay.

[0085] The dehydration catalyst used in step b3) is advantageously shaped into particles of various shapes and sizes. It is advantageously used in the form of cylindrical extrudates or multi-lobed extrudates (such as straight or twisted double-lobed, three-lobed or multi-lobed extrudates), but can also optionally be produced and used in the form of ground powder, tablets, rings, beads, wheels or spheres. Preferably, the catalyst is in the form of extrudates.

[0086] The dehydration catalyst used in step b3) is advantageously used in at least one reactor, fixed bed or moving bed.

[0087] In step b3) of the method according to the present invention, the catalyst used and the operating conditions are selected such that ethylene production is maximized. The overall dehydration reaction carried out in step b3) of the method according to the present invention is as follows: The conversion rate of the ethanol raw material in step b) of the method according to the present invention is greater than 90%, preferably 95%, and more preferably greater than 99%.

[0088] A conversion rate lower than 90% has the effect of reducing the overall yield of the method, and a relatively large amount of diethyl ether that is not converted into ethylene will be lost in the downstream separation step.

[0089] The conversion rate of the ethanol raw material is defined in percentage by the following mathematical formula: [1 - (mass of ethanol leaving per hour / mass of ethanol entering per hour)] × 100 The mass of ethanol entering and leaving per hour is measured in a conventional manner, for example, by chromatography.

[0090] Step b3) of carrying out the dehydration reaction is advantageously carried out in one or two reactors. The preferred reactor is a radial reactor operating in an upward or downward mode. In step b3) of the method according to the present invention, the conversion of the raw material is accompanied by the deactivation of the dehydration catalyst due to coking and / or adsorption of inhibitor compounds. Therefore, the dehydration catalyst must be regenerated regularly. Preferably, the reactor is used in an alternating regeneration mode, also known as a swing reactor, so as to alternately carry out the reaction and regeneration stages of the dehydration catalyst. The purpose of this regeneration treatment is to burn the organic deposits and nitrogen- and sulfur-containing substances present on the surface and inside of the dehydration catalyst. Optional pretreatment steps can reduce the amount of basic impurities, organic impurities, and cationic substances that will change the catalyst cycle time. Therefore, removing these substances can limit the number of regenerations of the catalyst.

[0091] Optionally, for example, in the case where the evaporation raw material does not contain any recycled water stream or any water stream external to the method, the number of reactors can be increased to compensate for the endothermicity of the reaction by the presence of an intermediate furnace during the ethanol dehydration reaction.

[0092] The effluent from the last adiabatic reactor of step b3) is optionally sent to a single-phase gas exchanger, in which the effluent is "cooled (superheated)" by heat exchange with the compressed raw material from the optional compression step without being condensed, and the compressed raw material itself is superheated.

[0093] Then, the "cooled (superheated)" effluent is advantageously sent to a second gas / liquid exchanger, in which it is partially condensed by heat exchange and thus used to evaporate the evaporation raw material.

[0094] Separation step b4) (optional) In one embodiment according to the present invention, the effluent from step b3) undergoes step b4) and is separated into an effluent containing ethylene with a pressure less than 1 MPa and an effluent containing water.

[0095] The separation of the dehydrated effluent obtained in step b4) can advantageously be carried out by any method known to those skilled in the art, for example, by means of a gas / liquid separation zone and preferably by a gas / liquid separation column.

[0096] The effluent containing ethylene at a pressure below 1 MPa is then advantageously compressed. The compression can raise the pressure of the effluent to a pressure advantageously between 2 MPa and 4 MPa required for its final purification.

[0097] Preferably, the effluent containing ethylene separated at the end of step b4) is not recycled to at least one adiabatic reactor of step b3). The non-recycling of the ethylene separated at the end of step b4) to at least one adiabatic reactor of step b3) does not impair the ethylene selectivity of the process.

[0098] Optionally, at least a part of the effluent containing water produced in step b4) is recycled to separation step b4). In the case of recycling at least a part of the effluent containing water, it is advantageous to cool the part of the effluent containing water by means of a cold fluid or a fluid produced by the process and preferably to purify it according to the purification methods known below.

[0099] Purification step b5) (optional) According to one embodiment of the present invention, at least a part of the effluent containing water produced in separation step b4) will undergo purification step b5). The purification step b5) can advantageously be carried out by any purification method known to those skilled in the art. For example, the purification step b5) can advantageously be carried out by using ion exchange resins, molecular sieves, membranes, by adding chemical reagents for adjusting the pH value (such as sodium hydroxide or amines), and by adding chemical reagents for stabilizing the product (such as polymerization inhibitors selected from bisulfites and surfactants).

[0100] Then at least one purified water stream and at least one unreacted ethanol stream are separated. The separation can advantageously be carried out by any separation method known to those skilled in the art. For example, the separation can advantageously be carried out by distillation, using molecular sieves, membranes, steam stripping or thermal stripping, or by absorption with a solvent (such as a (ethylene) glycol solvent).

[0101] A stream containing light gases (preferably acetaldehyde and methanol) can also be advantageously separated.

[0102] Using the purified water stream from step b5) allows the separation of the vast majority of ethylene from water before recycling. Thus, in the process according to the present invention, ethylene is separated from the diluent, thereby allowing the use of an inert thermal reaction diluent in the process. Doing so can also improve the energy recovery rate without reducing the final ethylene yield and selectivity.

[0103] Third reaction stage (step c) of the process according to the invention) The third reaction stage 7 includes at least one reactor, in which the ethylene 6 obtained at the end of step b) and the CO2 4 obtained at the end of step a) are used for the synthesis of acrylate in the reactor. In the reactor, the ethylene 6 from the second reaction stage 5, the CO2 4 from the first reaction stage 2, the catalytic precursor and the reaction solvent come into contact to form an active substance. The term "active substance" refers to the substance formed when the catalytic precursor, CO2 and ethylene come into contact. When the active substance comes into contact with a base, the synthesis of acrylate is completed. The base may be soluble in the reaction solvent or insoluble in the reaction solvent. The base may also be loaded on a solid support. The base may already be present in the reactor when the reactants come into contact in the reactor, or may be introduced in a step after the formation of the active substance. Preferably, the base is miscible with the solvent. In a more preferred manner, the base is introduced into the reactor simultaneously with the other reactants.

[0104] Base The base is generally an alkoxide, such as a phenoxide or an alkanolate. In a more preferred manner, the base is selected from the alkanolates of secondary or tertiary alcohols (such as tert-butanol, isopropanol, etc.). These salts generally contain inorganic counterions, such as Li, Na, Ca and Cs. If the ion exchange step is not considered, the base counterion will combine with the final acrylate. Preferably, the base will be a sodium salt, and the final acrylate will be sodium acrylate.

[0105] Catalytic precursor Generally, the catalyst is a transition metal complex. Nickel(0) and palladium(0) complexes are preferably used in the examples. It is also possible to use nickel(2) or palladium(2) salts as raw materials and reduce them in the presence of a reducing agent (such as H2, Mg, Na or Zn) to form nickel(0) or palladium(0) complexes. Preferably, Pd(0) is the preferred metal, preferably in the form of [Pd(PPh3)4].

[0106] Generally speaking, the most active ligands seem to be polydentate ligands containing at least one phosphine coordinated to the metal center. In a more preferred manner, these are basically bidentate ligands of the (P,P); (P,N); (P,O); (P, carbene) type. In an even more preferred manner, (P,P) ligands are used, preferably 1,2-bis(dicyclohexylphosphino)ethane, 1,3-bis(dicyclohexylphosphino)propane and 1,4-bis(dicyclohexylphosphino)butane, to obtain the best results.

[0107] The catalytic precursor is usually a mixture of a metal precursor and one or more ligands. Preferably, the catalytic precursor is a stoichiometric mixture of a bidentate ligand and a metal precursor. The metal precursor can be ( Non-in-situ ) before the reaction ( In-situ( ) It is formed in a reaction solvent or other solvents.

[0108] Solvent The solvent may be selected from aromatic compounds, halogenated aromatic compounds, ethers, alcohols, amides and ureas. The solvent is preferably selected from anisole, cyclohexylpyrrolidone, N,N-dibutylformamide and dimethylacetamide.

[0109] The reaction is generally carried out at a total pressure of 1 MPa to 10 MPa. The CO2 / ethylene partial pressure ratio is preferably from 1 / 10 to 10 / 1. More preferably, the ratio is from 2 / 8 to 8 / 2, and even more preferably from 2 / 1 to 1 / 2. The reaction temperature is preferably from 105 °C to 170 °C, more preferably from 125 °C to 165 °C, and even more preferably from 135 °C to 155 °C.

[0110] Separation step d) (optional) After the reaction is completed, the separation step of the acrylate is advantageously carried out. In a preferred manner, an anti-solvent that is immiscible with the reaction solvent is added to the reaction medium, and the whole is sent to a liquid-liquid separation step. In an even more preferred manner, the anti-solvent is water, which may be partially from the dehydration of ethanol in step b). At the outlet of the liquid-liquid separation, two streams are recovered, namely: - A first stream containing the reaction solvent and the catalytic precursor; and - A second stream, which is said to contain an anti-solvent rich in acrylate and the alcohol corresponding to the base used in the reaction.

[0111] Advantageously, after any drying to remove trace water, the first stream is reinjected into the reactor to recover the catalyst and continue the production of acrylate.

[0112] Advantageously, the second stream is sent to another separation step, preferably a distillation step, where the anti-solvent, alcohol and acrylate are separated.

[0113] Advantageously, the stream rich in anti-solvent can thus be recycled to the liquid-liquid extraction step.

[0114] Advantageously, the stream rich in alcohol is sent to a base regeneration step. In this step, the alcohol contacts a strong base to reform the strong base, which is then introduced into the reactor. Preferably, the strong base is sodium hydroxide, and the water generated during the regeneration can optionally be used as the anti-solvent.

[0115] Depending on its use, the acrylate can be recovered in the form of a concentrated solution in the anti-solvent, or separated and purified by distillation, drying or crystallization methods known to those skilled in the art.

[0116] The acrylate can also be subsequently converted to acrylic acid by adding an acid.

[0117] Examples 1 / Case of synthesizing sodium acrylate from glucose, without upgrading the CO2 of the fermentation step (not compliant): The glucose fermentation reaction equation is C6H 12 O6 → 2 C2H5OH + 2 CO2. As a result, 66.7% of the carbon in the glucose molecule is converted into ethanol, and 33.3% is converted into CO2.

[0118] For 170 Kta of glucose raw material, theoretically 86.8 Kta of ethanol and 83 Kta of CO2 can be produced by fermentation.

[0119] Assuming a yield of 97% for the dehydration of ethanol to produce ethylene, 51.2 Kta of ethylene can be produced, which is up to 172.1 Kta of sodium acrylate. Without upgrading CO2 to sodium acrylate, at most 64.7% of the carbon in glucose can be upgraded to sodium acrylate (see Table 1 below).

[0120] 2 / Case of synthesizing sodium acrylate from glucose, upgrading the CO2 from the fermentation step (compliant): For 170 Kta of glucose raw material, theoretically 86.8 Kta of ethanol and 83 Kta of CO2 can be produced by fermentation.

[0121] Assuming a yield of 97% for the dehydration of ethanol to produce ethylene, 51.2 Kta of ethylene can be produced, which is up to 172.1 Kta of sodium acrylate. To produce 172.1 Kta of sodium acrylate from 51.2 Kta of ethylene, at least 80.5 Kta of CO2 is required. Therefore, the CO2 generated by fermentation is sufficient for the CO2 self - sufficiency of the process.

[0122] Through the process described in the present invention, CO2 is upgraded to sodium acrylate, and up to 97% of the carbon in glucose can be upgraded to sodium acrylate (see Table 1 below).

[0123] Table 1 Biomass upgraded product Production in Kt / a <![CDATA[C% that can be upgraded to acrylate without upgrading CO2 (non-compliance)]]> <![CDATA[C% of acrylate that can be upgraded in the case of upgrading CO2 (not compliant)]]> Ethanol 86.8 64.7% 64.7% <![CDATA[CO2]]> 83.0 32.3% Total 64.7% 97.0%

Claims

1. A method for converting biomass into acrylate, successively including: a) A step of treating biomass to produce ethanol and carbon dioxide; b) A step of dehydrating the ethanol obtained at the end of step a) to obtain ethylene; c) A step of synthesizing acrylate from the ethylene obtained at the end of step b) and the carbon dioxide obtained at the end of step a) in the presence of a catalytic precursor and a solvent.

2. The method according to claim 1, wherein step a) includes the following sub-steps: a1) A step of pre-treating biomass to obtain a pre-treated substrate; a2) A step of subjecting the pre-treated substrate obtained at the end of step a1) to enzymatic hydrolysis or chemical hydrolysis to obtain an enzymatic hydrolysis or chemical hydrolysis slurry; a3) A step of subjecting the enzymatic hydrolysis or chemical hydrolysis slurry obtained at the end of step a2) to alcohol fermentation to obtain ethanol and carbon dioxide.

3. The method according to claim 2, wherein sub-step al) is carried out by steam explosion at a temperature between 150°C and 250°C for a time between 5 minutes and 30 minutes under acidic conditions.

4. The method according to claim 2 or 3, wherein sub-step a2) is carried out by enzymatic hydrolysis in the presence of cellulase produced by Trichoderma reesei.

5. The method according to claim 2, wherein when step a2) is enzymatic hydrolysis, steps a2) and a3) are carried out simultaneously.

6. The method according to any one of claims 1 to 5, wherein step b) includes the following sub-steps: b1) A step of evaporating an evaporation feedstock containing the ethanol obtained at the end of step a) in a heat exchanger, the evaporation feedstock being introduced into the evaporation step at a pressure between 0.1 MPa and 2.5 MPa to produce an evaporated feedstock; b2) A step of superheating the evaporated feedstock obtained at the end of step b1) to bring the evaporated feedstock to an inlet temperature suitable for the dehydration reaction temperature; b3) A step of dehydrating the feedstock obtained from step b2) in at least one adiabatic reactor, the adiabatic reactor containing at least one dehydration catalyst, and the dehydration reaction occurring in the adiabatic reactor, the adiabatic reactor operating at an inlet temperature of 350°C to 550°C and an inlet pressure of 0.3 MPa to 1.8 MPa.

7. The method according to any one of claims 1 to 6, wherein step c) is carried out at a temperature between 105°C and 170°C and at a pressure between 1 MPa and 10 MPa.

8. The method according to any one of claims 1 to 7, wherein step c) is carried out in the presence of a base selected from alkoxides of secondary or tertiary alcohols.

9. The method according to any one of claims 1 to 8, wherein step c) is carried out in the presence of a catalytic precursor of a transition metal-based metal complex, the transition metal-based metal complex being selected from nickel(0) and palladium(0) complexes.

10. The method according to any one of claims 1 to 9, wherein step c) is carried out in the presence of a solvent selected from anisole, cyclohexylpyrrolidone, N,N-dibutylformamide, and dimethylacetamide.

11. The method according to any one of claims 1 to 10 further comprises a step d) of liquid-liquid separation of the acrylate in the presence of a back-extraction solvent immiscible with the solvent used in step c).

12. The method according to claim 11, wherein the back-extraction solvent is water produced at least in part by dehydration of ethanol in step b).

13. The method according to any one of the preceding claims, characterized in that The biomass is lignocellulosic biomass.

14. A device for converting biomass into acrylate, capable of performing the method according to any one of claims 1 to 13, the device comprising: - a first reaction section (2) for producing ethanol (3) and carbon dioxide (4) from biomass (1); - a second reaction section (5) for dehydrating ethanol (3) into ethylene (6); and - a third reaction section (7) for producing acrylate (8) from ethylene (6) and carbon dioxide (4).

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