Conversion of biomass-derived hydrocarbon feedstocks to acrylates.

Abstract

The present invention relates to a method and a plant for converting biomass into acrylates, which method comprises the following steps in succession: a) treating biomass to produce ethanol and CO2, b) dehydrating the ethanol obtained at the end of step a) to obtain ethylene, and c) synthesizing acrylates from the ethylene obtained at the end of step b) and the CO2 obtained at the end of step a).

Description

[Technical Field]

[0001] The present invention relates to a method for processing biomass, preferably lignocellulosic biomass, to produce acrylates from a single bio-based carbon source while simultaneously maximizing carbon yield.

[0002] Lignocellulosic biomass fermentation allows for the production of ethanol and CO2, which can be advantageously converted to acrylates compared to prior art. [Background technology]

[0003] Acrylates are derivatives of acrylic acid and are used, among other things, to produce superabsorbent polymers from acrylic acid. Those skilled in the art know that just as acrylates can be synthesized from acrylic acid by adding a base, acrylic acid can also be synthesized from acrylates by adding an acid.

[0004] Currently, acrylic acid is produced industrially at high temperatures by oxidizing propylene in the presence of heterogeneous catalysts. However, the relatively high price of propylene has a strong impact on the price of acrylic acid, and several methods for synthesizing acrylic acid have been developed, including methods starting from carbon monoxide. Patent Document 1 relates to the Reppe process, which allows the synthesis of acrylic acid from acetylene and carbon monoxide. Although this process is implemented industrially, the synthesis of acrylic acid via the oxidation of propylene remains more economically viable.

[0005] Another alternative being explored is the synthesis of acrylic acid or its derivatives starting from carbon dioxide (CO). CO has the advantage of being inexpensive, and upgrading it in the form of a high-value-added product is an attractive approach to reducing its environmental impact. Patent Document 2 discloses a method for producing acrylic acid via the formation of propiolactone using ethylene oxide and carbon monoxide. In certain embodiments, the propiolactone formation step is carried out in the presence of ethylene oxide and CO.

[0006] In another approach, US Pat. No. 6,299,499 proposes using CO2 as a precursor to carbon monoxide in the context of the above-mentioned Reppe process.

[0007] Finally, another alternative is to use CO directly without going through the carbon monoxide reduction process. There is a large body of literature on the synthesis of carboxylic acids or carboxylates from CO and olefins, especially ethylene. As examples, mention may be made of US Pat. Nos. 4,613,299, 4,749,102, 4,793,112, 4,849,143, 4,893,154, 4,949,162, 4,949,172, 4,949,182, 4,949,192, 4,949,193, 4,949,194, 4,949,195, 4,949,196, 4,949,197, 4,949,198, 4,949,199, 4,949,199, 4,9

[0008] Ethylene can be produced from fossil resources via steam cracking processes, but it can also be produced by dehydration of bioethanol. It is well known that bioethanol can be produced by fermentation of sugars from various biomass. However, fermentations that produce ethanol generally do not have good "carbon" yields because some of it is lost in the form of CO2. Furthermore, ethanol produced from "first generation" (1G) biomass competes with the agri-food sector, and losing a large portion 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 via the synthesis of lactic acid. Unlike the previously mentioned routes, these do not use CO2 or ethylene. The process of converting biomass to lactic acid generally does not produce CO2, but the dehydration of lactic acid to acrylic acid is not trivial.

[0010] The present invention is therefore directed towards overcoming all the above-mentioned drawbacks. More precisely, the object of the present invention is to develop a method for processing biomass, preferably "second generation" (2G) lignocellulosic biomass, to produce acrylates from ethanol and CO2 produced from fermentation. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] U.S. Patent No. 3,023,237 [Patent Document 2] US Patent Application Publication No. 2016 / 016876 [Patent Document 3] US Patent Application Publication No. 2018 / 057439 [Patent Document 4] International Publication No. 2019 / 053541 [Patent Document 5] International Publication No. 2019 / 053540 [Patent Document 6] International Publication No. 2015 / 173296 [Patent Document 7] Chinese Patent Application Publication No. 104418737 [Patent Document 8] Chinese Patent Application Publication No. 105622400 Summary of the Invention [Means for solving the problem]

[0012] (Subject of the invention) In the aforementioned context, a first objective of the present description is to overcome the problems of the prior art and upgrade bio-based carbon, in particular in the form of CO2, to high value added compounds, in particular acrylates. Specifically, the present invention relates to a method for producing acrylates by an arrangement of steps that allows the conversion of biomass to ethanol and CO2, and then the conversion of these products to acrylates, using one or more of the following steps in addition to or instead of certain steps in conventional acrylate synthesis:

[0013] According to a first aspect, the present invention relates to a method for converting biomass into acrylates, said method comprising the following steps in succession: a) treating biomass to produce ethanol and carbon dioxide; b) dehydrating the ethanol obtained at the end of step a) to obtain ethylene; c) synthesizing acrylates 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 catalyst precursor and a solvent.

[0014] The invention is based on upgrading CO2, a by-product formed during the fermentation of biomass to ethanol, and optionally reusing water generated during the dewatering step in other steps of the process according to the invention. The invention therefore presents a series of unit operations that serve to maximize the carbon yield of the synthesis of acrylates from biomass, preferably lignocellulosic biomass, and even more preferentially "second generation" (2G) lignocellulosic biomass.

[0015] According to one or more embodiments, step a) comprises the following substeps: a1) pretreating biomass to obtain a pretreated substrate; a2) enzymatic or chemical hydrolysis of the pretreated substrate obtained at the end of step a1), obtaining a must of the enzymatic or chemical hydrolysis; a3) step of alcoholic fermentation of the must of enzymatic or chemical hydrolysis obtained at the end of step a2), obtaining ethanol and carbon dioxide.

[0016] 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. and for a duration between 5 and 30 minutes.

[0017] According to one or more embodiments, substep a2) is carried out by enzymatic hydrolysis in the presence of Trichoderma reesei cellulase.

[0018] According to one or more embodiments, when step a2) is an enzymatic hydrolysis, steps a2) and a3) are carried out simultaneously.

[0019] According to one or more embodiments, step b) comprises the following substeps: b1) vaporizing the ethanol-containing vaporized feedstock obtained at the end of step a) in a heat exchanger; the vaporized feedstock is introduced into the vaporization step at a pressure of 0.1 MPa to 2.5 MPa; to produce a vaporized feedstock; b2) superheating the vaporized feedstock obtained at the end of step b1) to bring the vaporized feedstock to an inlet temperature compatible with the dehydration reaction temperature; b3) Dehydrating said feedstock obtained from step b2) in at least one adiabatic reactor containing at least one dehydration catalyst and carrying out the dehydration reaction; operating at an inlet temperature between 350°C and 550°C and an inlet pressure between 0.3 MPa and 1.8 MPa.

[0020] According to one or more embodiments, step c) is carried out at a temperature of 105° C. to 170° C. and at a pressure of 1 MPa to 10 MPa.

[0021] According to one or more embodiments, step c) is carried out in the presence of a base selected from alkanolates of secondary or tertiary alcohols.

[0022] According to one or more embodiments, step c) is carried out in the presence of a catalyst precursor based on a metal complex of a transition metal chosen from complexes of nickel(0) and palladium(0).

[0023] 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.

[0024] According to one or more embodiments, the method also comprises a step d) of liquid-liquid separation of the acrylate salt in the presence of a counter-solvent that is immiscible with the solvent used in step c).

[0025] According to one or more embodiments, the antisolvent is water resulting at least in part from step b) of dehydrating ethanol.

[0026] According to one or more embodiments, the biomass is lignocellulosic biomass.

[0027] According to a second aspect, the present invention relates to an installation for converting biomass into acrylates, capable of carrying out the method according to the invention, said installation comprising: - a first reaction section, which makes it possible to produce ethanol and carbon dioxide from biomass; - A second reaction section; dehydrating ethanol to ethylene; and - a third reaction section, which makes it possible to produce acrylates from ethylene and carbon dioxide. DETAILED DESCRIPTION OF THE INVENTION

[0028] (List of drawings) FIG. 1 shows a schematic diagram of one embodiment of a method and installation according to the invention, making it possible to produce acrylates from biomass, preferably lignocellulosic biomass.

[0029] (Description of the embodiment) Embodiments of a method according to a first aspect of the present invention and an apparatus according to a second aspect of the present invention will now be described in detail. In the following detailed description, numerous specific details are disclosed to provide a deeper understanding of the method and apparatus. However, it will be apparent to those skilled in the art that the method and apparatus can be utilized without these specific details. In other cases, well-known features have not been described in detail to avoid unnecessarily complicating the description.

[0030] (definition) In this patent application, the term "to comprise" is synonymous with (means the same as) "to include" and "to contain" and is inclusive or open-ended and does not exclude other elements not recited. The term "to comprise" is understood to include the exclusive and closed-ended term "to consist of." Furthermore, in this description, an effluent comprising essentially or solely compound A corresponds to an effluent comprising at least 90% by weight, preferably at least 95% by weight, and highly preferably at least 99% by weight of compound A.

[0031] In this patent application, groups of chemical elements are given by default according to the CAS classification (CRC Handbook of Chemistry and Physics, published by CRC Press, editor-in-chief DR Lide, 81st ed., 2000-2001). For example, group VIII (or group VIIIB) according to the CAS classification corresponds to metals from columns 8, 9 and 10 according to the new IUPAC classification, and group VIB according to the CAS classification corresponds to metals from column 6 according to the new IUPAC classification.

[0032] In this patent application, "biomass" refers to any biologically produced feedstock, preferably produced by fermentation of sugars (saccharose, glucose, fructose and sucrose) derived from sugar-producing plant crops such as sugarcane, sugars derived from beetroot, or sugars derived from starch plants (starch), or sugars derived from lignocellulosic biomass, or sugars derived from hydrolyzed cellulose (glucose (mainly) and xylose, galactose), and containing variable amounts of water. Preferably, the biomass is lignocellulosic biomass, and even more preferentially "second generation" (2G) lignocellulosic biomass.

[0033] (Detailed explanation) The present invention may be defined as a process comprising a series of reaction steps making it possible to produce acrylates from biomass, preferably lignocellulosic biomass, and even more preferentially from "second generation" lignocellulosic biomass (2G). More particularly, the present invention relates to a process for converting biomass into acrylates, comprising the following steps in succession: a) treating biomass, preferably lignocellulosic biomass, to produce ethanol and carbon dioxide (CO2); b) dehydrating the ethanol obtained at the end of step a) to obtain ethylene; c) synthesis of acrylates from the ethylene obtained at the end of step b) and the CO2 obtained at the end of step a).

[0034] Furthermore, the invention can also be defined as an installation suitable for carrying out the method according to the invention, as shown in FIG. 1, said installation comprising, inter alia: - a first reaction section (2) making it possible to produce ethanol (3) and CO2 (4) from biomass (1); - a second reaction section (5), which dehydrates ethanol (3) to ethylene (6); - a third reaction section (7); which makes it possible to produce acrylates (8) from ethylene (6) and CO2 (4).

[0035] (First reaction section (step a) of the method according to the invention) The first reaction section (2) makes it possible to produce ethanol (3) and CO2 (4) from biomass (1).

[0036] In one embodiment of the present invention, the biomass used in the method is lignocellulosic biomass, preferably "second generation" lignocellulosic biomass. Hardwood and cereal straw are the most commonly used substrates. Most of them consist of approximately 40% to 50% cellulose, 20% to 25% hemicellulose, and 15% to 25% lignin. Other sources can be used: dedicated forestry crops, residues from alcohol-, sugar-, and grain-producing plants, residues from the paper industry, and products from the processing of cellulose- and lignocellulosic-based materials.

[0037] In one embodiment according to the invention, the method for converting biomass to ethanol more particularly comprises the following substeps: a1) pretreating biomass, preferably lignocellulosic biomass; obtaining a pretreated substrate; a2) enzymatic or chemical hydrolysis of the pretreated substrate obtained at the end of step a1), obtaining a must of the enzymatic or chemical hydrolysis; a3) step of alcoholic fermentation of the must of enzymatic or chemical hydrolysis obtained at the end of step a2); obtaining ethanol and CO2.

[0038] (Physicochemical pretreatment (step a1)) The pretreatment step a1) allows the production of a pretreated substrate containing the sugars contained in the hemicellulose in the form of monomers, essentially pentoses such as xylose and arabinose, and hexoses such as galactose, mannose, and glucose, improving the accessibility of the cellulose embedded in the lignin and hemicellulose matrix. A wide range of techniques are available, including acid cooking, alkaline cooking, steam explosion, and organosolv pulping. The effectiveness of the pretreatment is measured by the hemicellulose recovery content and the susceptibility of the cellulose residue to hydrolysis. Under mild conditions, acid pretreatment by steam explosion is most suitable, as it allows complete recovery of pentoses and good accessibility of the cellulose to hydrolysis.

[0039] Preferably, pretreatment step a1) is carried out by steam explosion under acidic conditions, advantageously at a temperature between 150°C and 250°C, advantageously for a period of 5 to 30 minutes. In this embodiment, step a1) makes it possible to convert hemicellulose into monomers while simultaneously minimizing losses, in particular furfural and the main sugar xylose. The released sugars are then extracted by washing in an aqueous phase. The solid residue obtained at the end of the extraction (i.e., the pretreated substrate, also referred to herein as cellulosic residue) contains only cellulose and lignin.

[0040] (Enzymatic hydrolysis or chemical hydrolysis (step a2)) The pretreated substrate obtained at the end of step a1) is then hydrolyzed either with acids (i.e. chemically) or enzymatically with cellulolytic and / or hemicellulolytic enzymes. Microorganisms, such as fungi belonging to the genera Trichoderma, Aspergillus, Penicillium, or Schizophyllum, or anaerobic bacteria, for example, belonging to the genus Clostridium, produce these enzymes, including in particular cellulases and xylanases, suitable for the total hydrolysis of plant polymers.

[0041] The acidic route, carried out with strong acids, more particularly sulfuric acid, is effective but requires large amounts of chemical products (acid, then base for neutralization). Enzymatic hydrolysis does not have this drawback; moreover, it can be carried out under mild conditions and is effective.

[0042] Preferentially, the pretreated substrate, with or without liberation from the hydrolyzed hemicellulose fraction, and, where appropriate, lignin, are hydrolyzed with cellulolytic and / or hemicellulolytic enzymes produced by specialized strains. When the carbonaceous substrate is derived from cellulosic or lignocellulosic biomass, Trichoderma reesei cellulases are most effective and suitable. The pretreated substrate to be hydrolyzed is suitably suspended in an aqueous phase at a dry matter ratio of preferably 6% to 25%, preferably 10% to 20%, and the pH is adjusted to 4 to 5.5, preferably 4.8 to 5.2, and the temperature is adjusted to 40 to 60°C, preferably 45 to 50°C. The hydrolysis reaction is initiated by adding cellulase; the amount typically used is 10 mg to 30 mg of secreted protein per gram of pretreated substrate weight. The reaction generally lasts for 15 to 48 hours, depending on the effectiveness of the pretreatment, the composition of the cellulase mixture, and the amount of enzyme added. The reaction is monitored by assaying the released sugars, especially glucose. The sugar solution (mast) is then separated by filtration or centrifugation from the non-hydrolyzed solid fraction, which consists essentially of lignin; this must is used for ethanol fermentation. When the cellulose fraction is liberated from the hydrolyzed hemicellulose during the processing step, glucose is the major sugar contained in the must.

[0043] (Fermentation (step a3)) Alcoholic fermentation is a biochemical process in which the sugars (carbohydrates, mainly glucose) contained in the must are converted into alcohol, preferentially ethanol, in an air-free liquid medium (anaerobic). The process of fermenting sugars to obtain ethanol is well known to those skilled in the art.

[0044] Alcoholic fermentation is preferentially carried out at temperatures between 25° C. and 32° C. For a more complete description of traditional fermentation methods, reference may be made to the textbook "Biofuels: Current Status, Prospects and Development Challenges" by Daniel Ballerini, published in 2006 by Technip.

[0045] Typically, ethanol is separated from the fermentation must by distillation, with the residue consisting of stillage. Periodic or continuous distillation of ethanol is necessary because concentrations above 14% ethanol can "poison" certain yeasts, reducing productivity. Distillation is carried out to allow for the production of ethanol feedstock suitable for the dehydration methods described below.

[0046] The CO2 is recovered in gas form at the outlet of the fermenter. According to an essential aspect of the invention, the CO2 obtained at the end of the fermentation step is at least partially sent to the acrylate synthesis step (step c)) of the process according to the invention. The CO2 may be compressed by a compressor before storage or use.

[0047] The ethanol fermentation residue, after separation from the ethanol, may be used as an inducing carbon source or as the main carbon source for enzyme production, the concentration of which is preferably adjusted to obtain the carbon source concentration best suited to the method for producing cellulolytic and / or hemicellulolytic enzymes.

[0048] The steps of enzymatic hydrolysis and fermentation may be carried out simultaneously (simultaneous saccharification and fermentation (SSF) process), in which case they are advantageously followed by steps of distillation and separation of the alcohol obtained.

[0049] (Second reaction section (step b) of the process according to the invention) The second reaction section (5) makes it possible to produce ethylene (6) from the ethanol (3) obtained from the first reaction section (2) (see Figure 1).

[0050] The second reaction section makes it possible to dehydrate the ethanol obtained at the end of step a) of the process according to the invention to form ethylene. Ethanol dehydration is a process known to those skilled in the art, but it can be optimized to reduce the energy costs of the process, as described in patent application US 2013 / 190 547.

[0051] Advantageously, the ethanol feedstock used in step b) of the process according to the invention is a concentrated hydrated ethanol feedstock. The term "concentrated hydrated ethanol feedstock" means an ethanol feedstock comprising an ethanol mass percentage of 35% or more by weight. Preferably, said concentrated ethanol feedstock comprises ethanol in a mass percentage of 35% to 99.9% by weight relative to the total weight of the feedstock. Preferably, said concentrated ethanol feedstock comprises ethanol in a mass percentage of 35% to 96% by weight relative to the total weight of the feedstock. Said concentrated ethanol feedstock advantageously comprises, in addition to water, alcohols other than ethanol, such as methanol, butanol and / or isopentanol, in a content of less than 10% by weight, preferably less than 5% by weight, oxygen-based compounds other than alcohols, such as ethers, acids, ketones, aldehydes and / or esters, advantageously in a content of less than 1% by weight, and organic and inorganic nitrogen and sulfur, advantageously in a content of less than 0.5% by weight, the weight percentages being expressed relative to the total mass of the feedstock.

[0052] In one embodiment according to the present invention, step b) comprises the following substeps: b1) vaporizing the vaporized feedstock containing ethanol obtained at the end of step a) in a heat exchanger; the vaporized feedstock is introduced into the vaporization step at a pressure of 0.1 MPa to 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 compatible with the dehydration reaction temperature; b3) Dehydrating the feedstock obtained from step b2) in at least one adiabatic reactor; the adiabatic reactor contains at least one dehydration catalyst, and the dehydration reaction is carried out in an inlet temperature of 350°C to 550°C and an inlet pressure of 0.3 MPa to 1.8 MPa.

[0053] The ethanol feedstock used in the context of step b) of the process of the invention advantageously undergoes a pretreatment step before step b1) of vaporizing said feedstock, which makes it possible to remove impurities contained in the feedstock and limit the deactivation of the downstream dehydration catalyst, in particular nitrogen- and sulfur-containing compounds. Oxygen-based compounds present in the feedstock are not substantially removed.

[0054] Said step of pretreatment of the ethanol feedstock is advantageously carried out by means known to those skilled in the art, such as the use of at least one resin, adsorption of the impurities onto the solid, preferably at a temperature between 20°C and 60°C; the sequence comprises a first step of hydrocracking, operating at a temperature between 20°C and 80°C, followed by a step of incorporation into an acidic solid at a temperature between 20°C and 80°C, and / or a step of distillation. In the case of the use of at least one resin, said resin is preferably acidic and is used at elevated temperatures between 70°C and 200°C. The resin may optionally be preceded by a basic resin.

[0055] In the case where the pretreatment step is carried out by adsorption of the impurities onto a solid, said solid is advantageously chosen from molecular sieves, activated carbon, alumina and zeolites.

[0056] The above steps of pre-treatment of the ethanol feedstock make it possible to produce a purified ethanol fraction in which organic impurities have been removed, resulting in a purified feedstock with impurity levels compatible with the dehydration catalyst.

[0057] (Vaporization of Feedstock (Step b1)) The feedstock, which at least partly comprises optionally pretreated ethanol, obtained at the end of step a) of the process according to the invention is called vaporized feedstock. Said vaporized feedstock advantageously also comprises a water stream recycled according to recycling step b5) or a water stream external to the process. In this case, the mass ratio of the water stream, whether recycled or external to the process, to the pretreated ethanol stream is advantageously between 1 and 4, with the aim of reducing the ethanol partial pressure in the dehydration reactor(s) and making the process more selective for ethylene.

[0058] According to one embodiment of the invention, the process comprises a step b1) of vaporizing the vaporized feedstock to produce a vaporized feedstock, the vaporization being carried out by heat exchange in a heat exchanger with a heat source that may be internal or external to the process, or by direct heating (e.g., heating in a furnace) or any other technique known to a person skilled in the art.

[0059] 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.

[0060] (Optional Compression Step) In a preferred embodiment, the vaporized feedstock undergoes compression in a compression step to produce a compressed feedstock, which is advantageously carried out in any type of compressor known to those skilled in the art, in particular in a compressor of the radial compressor type with an integral gearbox, or a compressor comprising one or more blowers with radial impellers connected in series without intercooling, or a positive displacement compressor with or without lubrication.

[0061] The optional compression step makes it possible to form a heat pump integrated into the process, using a stream from the process to vaporize the vaporized feed from step b1) by heat exchange with the effluent from the dehydration step b3).

[0062] In case an optional compression step is carried out, the vaporized feedstock is introduced into the vaporization step b1) at a pressure between 0.1 MPa and 1.4 MPa, preferentially between 0.2 MPa and 0.6 MPa.

[0063] The pressure of the compressed feedstock at the end of the optional compression step is advantageously between 0.3 MPa and 1.8 MPa, preferentially between 0.5 MPa and 1.3 MPa. The outlet pressure of the feedstock is sufficiently high so that the condensation temperature of the effluent from the last reactor is higher than the vaporization temperature of the feedstock entering step b1), which is a prerequisite for the feasibility of step b1).

[0064] (Superheating step b2)) The vaporized feedstock, optionally compressed, can be heated in a single-phase gas-type exchanger by heat exchange with any stream internal or external to the process, preferably by heat exchange with the effluent from the last adiabatic reactor of step b3), in which the feedstock, optionally compressed, is superheated. In the case where heat exchange with the effluent coming in gaseous state from the last adiabatic reactor of step b3), is carried out, the effluent is "desuperheated" without being condensed.

[0065] In the case where an optional compression step is performed, the single-phase gas exchanger is a technology known to those skilled in the art, which allows minimizing the pressure drop while at the same time having a large exchange surface area. This gas / gas exchange at low pressure reduces the density of the heat flow through the exchanger walls (low transfer coefficient) and requires a large exchange surface area. Furthermore, pressure losses must be minimized so as to limit the compressor loading of the optional compression step. For example, this exchanger can be a pressurized plate exchanger in a Packinox® type calender supplied by Alphalaval®.

[0066] The vaporized feedstock is optionally compressed and optionally heated in the single-phase gas type exchanger, and then introduced into a heating facility, preferably a furnace, to bring it to an inlet temperature in at least one adiabatic reactor that is compatible with the temperature of the dehydration reaction.

[0067] (Dehydration step b3)) According to one embodiment of the invention, said feedstock obtained from step b2) is subjected to a dehydration step b3) in at least one adiabatic reactor containing at least one fixed bed of a dehydration catalyst and in which the dehydration reaction takes place.

[0068] The dehydration step b3) is advantageously carried out in one or two reactors.

[0069] In the case where step b3) is carried out in a single adiabatic reactor, said compressed and optionally heated feedstock is advantageously introduced into said reactor 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.

[0070] The temperature of the effluent from the adiabatic reactor in step b3) is advantageously between 270°C and 450°C, preferably between 340°C and 430°C, and the outlet pressure is between 0.2MPa and 1.6MPa, preferably between 0.3MPa and 0.8MPa.

[0071] In the case where step b3) is carried out in two adiabatic reactors, said compressed and optionally heated feedstock is advantageously introduced into the first reactor at an inlet temperature between 350°C and 550°C, preferably at a temperature between 370°C and 500°C, and at an inlet pressure between 0.3 MPa and 1.8 MPa, preferably between 0.4 MPa and 1.1 MPa.

[0072] The effluent from the first adiabatic reactor advantageously leaves said 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.

[0073] The effluent is then advantageously placed in a furnace such that the inlet temperature of the effluent to the second adiabatic reactor is between 350° C. and 550° C., preferably between 400° C. and 500° C. The effluent, upon entering the second reactor, advantageously has a pressure of between 0.3 MPa and 1.7 MPa, preferably between 0.3 MPa and 0.9 MPa.

[0074] The effluent from the second adiabatic reactor advantageously leaves said second adiabatic reactor at a temperature between 270° C. and 450° C., preferably between 340° C. and 430° C. The outlet pressure of said effluent from the second adiabatic reactor is advantageously between 0.2 MPa and 1.6 MPa, preferably between 0.3 MPa and 0.8 MPa.

[0075] The inlet temperature of the reactor(s) may advantageously be increased gradually to avoid deactivation of the dehydration catalyst.

[0076] The dehydration reaction carried out in the at least one adiabatic reactor of step b3) of the present process is advantageously carried out for 0.1 to 20 h -1 , preferably 0.5 to 15 hours -1 The catalyst is operated at a weight hourly space velocity (WHSV) of 1000 rpm, where WHSV is defined as the ratio of the mass flow rate of the pure ethanol feedstock to the mass of the catalyst.

[0077] The dehydration catalysts used in step b3) are catalysts known to those skilled in the art.

[0078] The catalyst may be an amorphous acid catalyst, a zeolitic acid catalyst, a silica-alumina based catalyst, an alumina based catalyst or a silica-alumina based catalyst.

[0079] The catalyst is preferably an amorphous acid catalyst or a zeolitic acid catalyst.

[0080] In the case where the dehydration catalyst used in step b3) is a zeolite catalyst, the at least one zeolite contained in the catalyst is selected from zeolites having pore openings containing at least 8, 10, or 12 oxygen atoms (8MR, 10MR, or 12MR). Specifically, it is known that the size of the pores in a zeolite is determined by the number of oxygen atoms forming the ring portion of the zeolite channel, called the "member ring" or MR. Preferably, the zeolite dehydration catalyst comprises at least one zeolite having a structure type selected from MFI, FAU, MOR, FER, SAPO, TON, CHA, EUO, MEL, and BEA structure types. Preferably, the zeolite dehydration catalyst comprises a zeolite of MFI structure type, preferably ZSM-5 zeolite.

[0081] The zeolites used in the dehydration catalysts used in step b3) of the process according to the invention may advantageously be modified by dealumination or desilication according to any dealumination or desilication method known to the person skilled in the art.

[0082] The zeolite used in the dehydration catalyst or in the final catalyst used in step b3) of the process may advantageously be modified with agents having properties that weaken its overall acidity and improve its hydrothermal resistance properties. Preferably, said zeolite or said catalyst advantageously contains phosphorus, preferably added in the form of H3PO4, followed by neutralization of excess acid with a basic precursor, for example calcium, followed by steaming. Preferably, said zeolite contains phosphorus in a content of 1 to 4.5% by weight, preferably 1.5 to 3.1% by weight, relative to the total mass of the catalyst.

[0083] Preferably, the dehydration catalyst used in step b3) is a catalyst described in patent applications WO 2009 / 098 262, WO 2009 / 098 267, WO 2009 / 098 268 or WO 2009 / 098 269.

[0084] In the case where the dehydration catalyst used in step b3) is an amorphous acid catalyst, said catalyst comprises at least one porous refractory oxide selected from alumina, alumina activated by mineral acid precipitation, and silica-alumina.

[0085] The amorphous or zeolitic dehydration catalyst used in step b3) may advantageously comprise at least one oxide-type matrix, also known as a binder. According to the invention, the term "matrix" means an amorphous or crystallized matrix, or one comprising amorphous and crystallized portions. The matrix is ​​advantageously chosen from elements of the group formed by clays (for example from natural clays such as kaolin or bentonite), magnesia, alumina, silica, silica-alumina, aluminates, titanium oxide, boron oxide, zirconia, aluminum phosphate, titanium phosphate, zirconium phosphate and charcoal, used alone or in a mixture. Preferably, the matrix is ​​chosen from elements of the group formed by alumina, silica and clay.

[0086] The dehydration catalyst used in step b3) is advantageously formed into granules of various shapes and sizes. It is advantageously used in the form of cylindrical extrudates or multilobe extrudates, such as bilobe, trilobe or multilobe extrudates, in straight or twisted form, but may also be produced and used in the form of crushed powder, tablets, rings, beads, wheels or spheres. Preferably, the catalyst is in the form of an extrudate.

[0087] The dehydration catalyst used in step b3) is advantageously used in at least one reactor in a fixed or moving bed.

[0088] In step b3) of the process according to the invention, the catalysts used and the operating conditions are chosen to maximize ethylene production. The overall dehydration reaction carried out in step b3) of the process according to the invention is as follows:

[0089] [ka]

[0090] The conversion of the ethanol feedstock in step b) of the process according to the invention is greater than 90%, preferably greater than 95%, more preferably greater than 99%.

[0091] Conversions below 90% have the effect of reducing the overall yield of the process, with large amounts of diethyl ether that are not converted to ethylene being lost in downstream separation steps.

[0092] The conversion of the ethanol feedstock is defined as a percentage by the following formula:

[0093] [1 - (mass of ethanol leaving per hour / mass of ethanol entering per hour)] x 100 The mass of ethanol entering and leaving each hour is measured in a conventional manner, for example by chromatography.

[0094] Step b3), in which the dehydration reaction takes place, is advantageously carried out in one or two reactors. Suitable reactors are radial reactors operating in upflow or downflow mode. During step b3) of the process according to the invention, the conversion of the feedstock is accompanied by deactivation of the dehydration catalyst due to coking and / or adsorption of inhibitor compounds. The dehydration catalyst must therefore undergo periodic regeneration steps. Preferably, the reactor is used in an alternating regeneration mode, also known as a swing reactor, in which phases of reaction and regeneration of the dehydration catalyst are alternated. The purpose of this regeneration treatment is to combust organic deposits and nitrogen- and sulfur-containing species present on the surface and within the dehydration catalyst. An optional pretreatment step makes it possible to reduce the amount of basic organic impurities and cationic species that would otherwise alter the catalyst's cycle time. Removal of these species therefore makes it possible to limit the number of catalyst regenerations.

[0095] In some cases, for example, in cases where the vaporized feedstock does not include any recycle water stream or any stream of water external to the process, the number of reactors can be increased to compensate for the endothermic nature of the reaction due to the presence of intermediate furnaces in the progression of the ethanol dehydration reaction.

[0096] The effluent from the last adiabatic reactor of step b3) is optionally sent to a single-phase gas exchanger where it is "desuperheated" and, for its part, superheated without being condensed by heat exchange with the compressed feed from the optional compression step.

[0097] The "desuperheated" effluent is then advantageously sent to a second gas / liquid type exchanger where it is partially condensed by heat exchange which serves to vaporize the vaporized feedstock.

[0098] (Separation step b4) (optional)) In one embodiment according to the invention, the effluent from step b3) undergoes a step b4) of separation at a pressure below 1 MPa into an effluent comprising ethylene and an effluent comprising water.

[0099] Step b4) of separation of said dewatered effluent resulting from step b3) may advantageously be carried out in any way known to the person skilled in the art, for example by means of a gas / liquid separation zone, preferably a gas / liquid separation column.

[0100] The effluent containing ethylene at a pressure below 1 MPa is advantageously subjected to compression, which makes it possible to increase the pressure of said effluent to the pressure advantageously between 2 MPa and 4 MPa required for its final purification.

[0101] Preferably, the effluent containing ethylene separated at the conclusion of step b4) is not recycled to the at least one adiabatic reactor of step b3).By not recycling the ethylene separated at the conclusion of step b4) into the at least one adiabatic reactor of step b3), the ethylene selectivity of the process is not impaired.

[0102] At least a portion of the water-containing effluent resulting from step b4) is optionally recycled to separation step b4). In the case where at least a portion of the water-containing effluent is recycled, said portion of the water-containing effluent is advantageously cooled with the aid of a cold or hot fluid or fluids resulting from the process and preferably purified according to known purification methods as described below.

[0103] (Purification step b5) (optional)) In one embodiment according to the invention, at least a portion of the water-containing effluent resulting from separation step b4) undergoes a purification step b5). Purification step b5) may advantageously be carried out by any purification method known to those skilled in the art. By way of example, purification step b5) may advantageously be carried out by using ion exchange resins, molecular sieves, membranes, by adding chemical agents for adjusting the pH, such as sodium hydroxide or amines, and by adding chemical agents for stabilizing the product, such as polymerization inhibitors selected from bisulfites and surfactants.

[0104] At least one purified water stream and at least one unconverted ethanol stream are then separated. The separation may advantageously be carried out by any separation method known to those skilled in the art. For example, the separation may advantageously be carried out by distillation, by using molecular sieves, membranes, steam or heat stripping, or by absorption in a solvent, for example a glycol solvent.

[0105] The stream containing light gases, preferably acetaldehyde and methanol, may advantageously be separated.

[0106] The use of the purified water stream from step b5) makes it possible to separate a large proportion of the ethylene from the water before it is recycled. The ethylene is therefore separated from the diluent in the process according to the invention, making it possible to use an inert thermally reactive diluent in the process. This also allows for improved energy recovery without reducing the final ethylene yield and selectivity.

[0107] (Third reaction section (step c) of the process according to the invention) The third reaction section (7) comprises at least one reactor in which the synthesis of acrylates is carried out from the ethylene (6) obtained at the end of step b) and the CO2 (4) obtained at the end of step a). In this reactor, the ethylene (6) from the second reaction section (5), the CO2 (4) from the first reaction section (2), the catalyst precursor, and the reaction solvent are brought into contact to form active species. The term "active species" refers to the species formed when the catalyst precursor, CO2, and ethylene are brought into contact. The synthesis of acrylates is completed when the active species are brought into contact with a base. This base may be soluble or insoluble in the reaction solvent. The base may be supported on a solid support. The base may already be present in the reactor during contact with the reactants in the reactor, or it may be introduced in a step after the formation of the active species. Preferentially, the base is miscible with the solvent. More preferentially, the base is introduced into the reactor simultaneously with the other reactants.

[0108] (base) The base is generally an alkoxide salt, such as a phenoxide salt or an alkanolate salt. More preferentially, the base is selected from the alkanolates of secondary or tertiary alcohols (tert-butanol, isopropanol, etc.). The salt generally contains an inorganic counterion, such as Li, Na, Ca, and Cs. The base counterion is the one that would be associated with the final acrylate salt if no ion exchange step is envisaged. Preferentially, the base is a sodium salt and the final acrylate is sodium acrylate.

[0109] (catalyst precursor) In principle, the catalyst is a transition metal complex. Preferentially, nickel(0) and palladium(0) complexes are used in the examples. It is also possible to start with a nickel(2) or palladium(2) salt, which is reduced in the presence of a reducing agent, such as H2, Mg, Na or Zn, to form a nickel(0) or palladium(0) complex. Preferentially, Pd(0) is the preferred metal, and is preferably in the form [Pd(PPh3)4].

[0110] In general, the most active ligands appear to be polydentate ligands containing at least one phosphine coordinated to the metal center. More preferentially, these are essentially bidentate ligands of the (P,P); (P,N); (P,O); (P,carbene) type. Even more preferentially, the best results are obtained with (P,P) ligands, preferentially 1,2-bis(dicyclohexylphosphino)ethane, 1,3-bis(dicyclohexylphosphino)propane, and 1,4-bis(dicyclohexylphosphino)butane.

[0111] The catalyst precursor is generally a mixture of a metal precursor and one or more ligands. Preferentially, the catalyst precursor is a stoichiometric mixture of a bidentate ligand with the metal precursor. The metal precursor may be formed ex situ before the reaction or in situ during the reaction in the reaction solvent or in another solvent.

[0112] (solvent) The solvent may be chosen from aromatic compounds, halogenated aromatic compounds, ethers, alcohols, amides and ureas. The solvent is preferentially chosen from anisole, cyclohexylpyrrolidone, N,N-dibutylformamide and dimethylacetamide.

[0113] The reaction is generally carried out at a total pressure of 1 MPa to 10 MPa. The CO2 / ethylene partial pressure ratio is preferably 1 / 10 to 10 / 1. More preferably, the ratio is 2 / 8 to 8 / 2, and even more preferably 2 / 1 to 1 / 2. The reaction temperature is preferably 105°C to 170°C, more preferably 125°C to 165°C, and even more preferentially 135°C to 155°C.

[0114] (Separation step d) (optional)) At the end of the reaction, it is advantageous to proceed through a step of separating out the acrylate salt. Preferentially, an antisolvent immiscible with the reaction solvent is added to the reaction medium, and the whole is sent to a liquid-liquid separation step. Even more preferentially, the antisolvent is water, which may be partially derived from the dehydration of ethanol in step b). At the outlet of the liquid-liquid separation, two streams are recovered: - a first stream; containing a reaction solvent and a catalyst precursor; and - a second stream; said to contain an antisolvent enriched with the alcohol corresponding to the acrylate and the base used in the reaction.

[0115] The first stream is advantageously reinjected into the reactor to recycle the catalyst and continue to produce acrylates, after optional drying to remove traces of water.

[0116] The second stream is advantageously sent to another separation step, preferentially a distillation step, to separate the antisolvent, the alcohol and the acrylate salt.

[0117] Advantageously, the antisolvent-enriched stream may therefore be recycled to the liquid-liquid extraction step.

[0118] Advantageously, the alcohol-rich stream is sent to a base regeneration step in which the alcohol is placed in contact with a strong base to reform the base, which is then introduced into the reactor. Preferentially, the strong base is sodium hydroxide, and the water generated during regeneration may optionally be used as an antisolvent.

[0119] Depending on its intended use, the acrylate salt may either be recovered in the form of a concentrated solution in the antisolvent, or isolated and purified by distillation, drying or crystallization methods known to those skilled in the art.

[0120] The acrylate salt may then be converted to acrylic acid by adding an acid.

[0121] (Example) (1 / Example of synthesis of sodium acrylate from glucose without upgrading CO2 in the fermentation process (non-compliant)) The equation for the glucose fermentation reaction is CH 12 O6 → 2C2H5OH + 2CO2 As a result, 66.7% of the carbon in the glucose molecule is converted to ethanol and 33.3% is converted to CO2.

[0122] If the feedstock is 170 Kta glucose, the fermentation can theoretically produce 86.8 Kta ethanol and 83 Kta CO2.

[0123] Assuming a 97% yield of ethanol dehydration to ethylene, 51.2 Kta of ethylene, or up to 172.1 Kta of sodium acrylate, can be produced. Without upgrading CO2 to sodium acrylate, up to 64.7% of the carbon in glucose can be upgraded to sodium acrylate (see Table 1 below).

[0124] (2 / Example of synthesis of sodium acrylate from glucose with CO2 upgrading from fermentation process (reference)) If the feedstock is 170 Kta glucose, the fermentation can theoretically produce 86.8 Kta ethanol and 83 Kta CO2.

[0125] Assuming a 97% yield of ethanol dehydration to ethylene, it is possible to produce 51.2 Kta of ethylene, or a maximum of 172.1 Kta of sodium acrylate. To produce 172.1 Kta of sodium acrylate with 51.2 Kta of ethylene requires at least 80.5 Kta of CO2. Fermentation therefore produces enough CO2 for the sequence to be self-sufficient in CO2.

[0126] When CO2 is upgraded to sodium acrylate by the sequences described in this invention, up to 97% of the carbon in glucose may be upgraded to sodium acrylate (see Table 1 below).

[0127] [Table 1]

[0128] [Brief explanation of the drawings]

[0129] [Figure 1] 1 shows a schematic diagram of one embodiment of a method and installation according to the invention, making it possible to produce acrylates from biomass, preferably lignocellulosic biomass.

Claims

1. 1. A method for converting biomass to acrylates, comprising the steps of: a) processing biomass to produce ethanol and carbon dioxide; b) dehydrating the ethanol obtained at the end of step a) to obtain ethylene; c) synthesizing acrylates 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 catalyst precursor and a solvent.

2. 10. The method of claim 1, wherein step a) comprises the following substeps: a1) pretreating biomass to obtain a pretreated substrate; a2) enzymatically or chemically hydrolyzing the pretreated substrate obtained at the end of step a1) to obtain an enzymatically or chemically hydrolyzed must; a3) Alcoholic fermentation of the must of the enzymatic or chemical hydrolysis obtained at the end of step a2) to obtain ethanol and carbon dioxide.

3. 3. The method according to claim 2, wherein 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 between 5 and 30 minutes.

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

5. 3. 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) comprises the following substeps: b1) vaporizing the ethanol-containing vaporized feedstock obtained at the conclusion of step a) in a heat exchanger; introducing the vaporized feedstock into the vaporization step at a pressure of 0.1 MPa to 2.5 MPa; producing a vaporized feedstock; b2) superheating the vaporized feedstock obtained at the end of step b1) to bring the vaporized feedstock to an inlet temperature compatible with the dehydration reaction temperature; b3) Dehydrating said feedstock obtained from step b2) in at least one adiabatic reactor containing at least one dehydration catalyst and in which the dehydration reaction takes place; operating at an inlet temperature between 350°C and 550°C and an inlet pressure between 0.3 MPa and 1.8 MPa.

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

8. 8. The process according to claim 1, wherein step c) is carried out in the presence of a base selected from alkanolates of secondary or tertiary alcohols.

9. 9. The process according to claim 1, wherein step c) is carried out in the presence of a catalyst precursor based on a metal complex of a transition metal selected from complexes of nickel(0) and palladium(0).

10. 10. The process 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. 11. The process according to any one of claims 1 to 10, also comprising a step d) of liquid-liquid separation of the acrylate salt in the presence of an antisolvent that is immiscible with the solvent used in step c).

12. 12. The method of claim 11, wherein the antisolvent is water resulting at least in part from step b) of dehydrating ethanol.

13. 13. The method according to any one of claims 1 to 12, wherein the biomass is lignocellulosic biomass.

14. An installation for converting biomass into acrylates, capable of carrying out the method according to any one of claims 1 to 13, said installation comprising: a first reaction section (2) making it possible to produce ethanol (3) and carbon dioxide (4) from the biomass (1); a second reaction section (5) for dehydrating ethanol (3) to ethylene (6); and a third reaction section (7), which makes it possible to produce acrylates (8) from ethylene (6) and carbon dioxide (4).

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