CH710004A2 - Method of preparation of lignocellulosic biomass for the production of bio-refinery products including ethanol and installation for the implementation of this method. - Google Patents

Abstract

The installation comprises means for pretreatment of said organic products to produce said lignocellulosic biomass, equipment for carrying out all the phases of the process on predetermined batches, in units adapted to said batches. The pretreatment means for said organic products for producing said lignocellulosic biomass comprise at least one mixing and cooking vessel (13) for the preparation of a mixture of organic products, in particular wood particles with a volume of water of between 75.degree. and 90% of the mass of the mixture, and the pressure cooking of said mixture. It comprises at least one expansion tank (14) for evacuating the water vapor and recovering a pasty mass, at least one pre-hydrolysis tank (15) or additional treatment for treatment in order to liquefy said molasses cutting the molecular chains to form a biomass rich in C 5 and C 6 sugars, these different units being arranged upstream of at least one fermentation vessel (16) followed by at least one distillation column (17), in particular for distil ethanol.

Description

Technical area

The present invention relates to a process for preparing lignocellulosic biomass based on various organic products, especially wood or the like, for the production of bio-refinery products and in particular ethanol, in which one carries out successively at least one pretreatment phase of said organic products to produce said biomass, at least one complementary phase of preparation for the fermentation of said biomass, a fermentation phase and a final distillation phase to separate the bio-refinery products and in particular ethanol from the others substances resulting from the treatment of said organic products, especially wood or the like.

It also relates to an installation for the implementation of the process for the preparation and processing of biomass based on various organic products, in particular wood particles, for the production of ethanol, comprising means for pretreatment of said organic products. for producing said biomass, at least one equipment for carrying out a complementary phase of preparation for the fermentation of said biomass, equipment for carrying out a fermentation phase and finally a distillation tower for separating the bio-refinery and in particular ethanol products other substances resulting from the treatment of said organic products, especially wood or the like.

Prior art

The article entitled "Biofuels" D. BALLERINI I.F.P. "New Energies" describes various processes for producing ethanol from lignocellulosic biomass. The main phases of these processes consist, in succession, in pretreating plant materials, in particular wood, generally containing cellulose, hemicellulose and lignin for the purpose of forming biomass, hydrolysis of biomass, ethanol fermentation and distillation to collect ethanol.

[0004] The article "Techno-Economics Analysis of Biochermical Scenarios for Production of Cellulosic Ethanol" by F. Kabir KAZI, J. FORTMAN and R. AN EX of the State University, published by the "NREL: National Renewable Energy Laboratory" , describes various variants of processes and facilities for producing biofuels and especially ethanol from cellulosic raw materials.

US Patent Application No. 2012 0111 321, assigned to the company: ABENGOA BIOENERGY NEW TECHNOLOGIES, INC describes a method and an apparatus for treating a cellulosic raw material, in order to produce, in particular ethanol .

The methods and installations for implementing these known methods recommend continuous operation, especially during certain operating phases. Such continuous operation makes it difficult to control operating parameters, in particular temperature, pressure and pH, the control of which is fundamental to avoid the formation of fermentation inhibitors, in particular, which may jeopardize one of the essential operating phases. , namely the enzematic fermentation, which is decisive for ensuring the best yield of ethanol production.

[0007] Other characteristic aspects of the known techniques, such as the amount of water added to the dry cellulosic raw material, the ability to produce a homogeneous biomass, the ability to rapidly raise the temperature of the biomass, the possibility of effectively regulate the pressure of the treated substances, create problems during the process phases and result in a random final output. Indeed, the fundamental problem of these techniques is related to the fact that the raw material does not have stable and constant qualities, so that the preparation of the biomass requires constant adjustments according to the nature of the treated material, its provenance, its quality. These adjustments can not be made on materials that run continuously and whose preparation is standardized according to supposedly constant parameters. The raw material of which at least a part of the characteristics is random, can not be processed according to a standardized process in which all the parameters are fixed, in order to obtain an optimal result whatever said raw material used. In addition traceability can not be ensured if the process works continuously and it is impossible to follow the raw material to be treated during all phases of treatment.

Presentation of the invention

The present invention is intended primarily to optimize the phases of the process so as to achieve a production of bio-refining products, in particular ethanol with an optimal guaranteed yield, and to achieve all phases of the process so reproducible in the context of a reliable installation, whatever the characteristics of batches of incoming raw materials. In addition, it proposes to adapt the phases of the process taking into account the variable characteristics of the raw materials, so as to guarantee in all cases an optimal production and a constant quality.

For this purpose, the method according to the invention is characterized in that all the phases of the method are carried out on predetermined batches, in processing units adapted to said batches, in that the parameters are adjusted. corresponding to each of the process steps for each of said predetermined batches by equipment combined with said units, and in that said pretreatment phase consists of a first step of preparing a mixture of organic products, in particular wood particles. with a volume of water between 75 and 90% of the mass of the mixture, a second step of pressure cooking said mixture, at a temperature between 150 and 200 ° C, at a treatment pressure of between 500 and 2000 kPa, and with a pH between 3.5 and 5, for a period of between 10 and 120 min, a third step of expanding said mixture to evacuate the water vapor and recovering a mass forming a kind of molasses and at least a fourth complementary step to prepare the fermentation of said biomass prior to distillation.

According to a first embodiment, said fourth complementary step to prepare the fermentation of said biomass is a pre-hydrolysis step in the presence of enzymes, this step having a duration of 6 to 12 hours to liquefy said molasses by cutting the molecular chains to form a biomass rich in C5 and C6 sugars.

According to a second embodiment, said fourth complementary step to prepare the fermentation of said biomass is a step of concentrating C5 and C6 sugars, in the presence of bacteria and / or fungi. According to a preferred embodiment, the number of lots n1 is determined; n2; n3; n4; by initially defining the number n4 of prehydrolysis units corresponding to the n4lots to be treated is sufficient to treat the molasses resulting from the n3units of relaxation, then by defining the number n3 of units of relaxation so that the total capacity of said n3units of relaxation corresponding to n3lots to be treated is sufficient to treat n2lots from the cooking units, then defining the number n2de firing units such that the total capacity of said n2units cooking is sufficient to treat said nlots of mixture from the mixing units.

Said first step of preparing a mixture of organic products and said second step of firing said mixture, said pretreatment phase is preferably performed by simultaneously introducing said mass of organic products, including wood particles and water in a pressure cooking vessel with stirring means into which an appropriate volume of steam is injected to ensure the required rise in the temperature of the mixture and said treatment pressure.

Said relaxation phase of said mixture for evacuating water vapor and for recovering said molasses, is advantageously carried out in an expansion tank for releasing the pressure of the water vapor.

Said fourth step of pre-hydrolysis in the presence of enzymes is carried out particularly advantageously in a specific treatment tank in which said molasses resulting from the relaxation phase and said enzymes are introduced in order to manufacture said rich biomass. in sugars C5 and C6.

Prior to said first phase of preparation of a mixture of organic products, it is preferably carried out a grinding of organic products, including wood particles and a determination of both the dry matter and additional water, said additional water being injected simultaneously with said dry material in said pressure cooking vessel, while mixing the mass to be treated.

[0016] Advantageously, said pre-hydrolysis of said lignocellulosic biomass can be carried out in the presence of enzymes, bacteria or fungi.

For this purpose also the device according to the invention is characterized in that it comprises appropriate units for performing all the phases of the method on predetermined batches, in units adapted to said batches, specific control means for adjusting the critical parameters corresponding to each of the phases of the process by equipment combined with the said containers, means for distributing the said batches in successive series arranged in cascade, each of the said predetermined batches being disposed in one of the said adapted units, and in that the said pre-processing means said organic products for producing said lignocellulosic biomass comprise at least one mixing and cooking vessel for the preparation of a mixture of organic products, in particular wood particles with a volume of water of between 75 and 90% of the mass of the mixing, at least the pressure cooking of the said mixture, with a temperature of between 150 and 200 ° C., at a treatment pressure of between 500 and 2000 kPa, and with a pH of between 3.5 and 5, for a period of between 10 and 120 minutes, at least one vessel of expansion of said mixture to evacuate the water vapor and recover a pasty mass forming a kind of molasses, at least one additional treatment tank to form a biomass rich in sugars C5 and C6, these different units being arranged upstream of at least one fermentation tank followed by at least one distillation column.

Said complementary treatment tank may be a prehydrolysis tank in the presence of enzymes for a treatment for a period of 6 to 12 hours in order to liquefy said molasses by cutting the molecular chains.

However, said complementary treatment tank may be a treatment tank in the presence of bacteria and / or enzyme fungi for a treatment intended to liquefy said molasses by cutting the molecular chains.

According to a preferred embodiment, the installation comprises a first series of n1units of mixture arranged to prepare n1lots of mixed material; n2combustion units arranged to provide vapor pressure cooking and mixing of the mixed material from the mixing units; n3units of relaxation to relax by removing steam from mixing products from n2units of cooking and to produce a kind of molasses free of steam; and n4promolysis units under the effect of enzymes to produce the lignocellulosic biomass to be fermented and then subjected to distillation.

Said pressure cooking vessel advantageously comprises stirring means for circulating the mixture it contains according to lateral ascending currents and axial central downward currents and means for injecting a suitable volume of water vapor for ensuring the required elevation of the temperature of the mixture and said treatment pressure inside the vessel.

Said brewing means advantageously comprise at least one rotary vane disposed horizontally at the bottom of the vat and driven on an axis arranged vertically inside said vat. In a particularly advantageous manner, the installation comprises at least one attritor mill mounted on a base which carries drive means and which contains transmission elements, said base, said drive means and said transmission elements constituting a predetermined mechanical unit adaptable to all the parts of the installation comprising moving elements.

Brief description of the drawings

The present invention and its advantages will appear better in the following description of embodiments given by way of non-limiting examples, with reference to the accompanying drawings, in which: <tb> fig. 1 <SEP> represents a schematic front view of the plant for preparing a lignocellulosic biomass for the production of bio-refinery products, in particular ethanol, <tb> fig. 2 <SEP> represents the plant for the preparation and transformation of a biomass for the production of bio-refinery products, in particular ethanol of FIG. 1, side view, illustrating a mode of operation in cascade, <tb> fig. 3 <SEP> is a schematic view of an attritor mill used in the context of the preparation of the raw material in order to implement the method of the invention, and <tb> fig. 4 <SEP> is a vertical sectional view of a mixing tank of the organic product mixture, used for the preparation phase of the lignocellulosic biomass,

Illustrations of the invention and different ways of achieving it

With reference to the figures, the method according to the invention is implemented by the plant according to the invention for the preparation of a lignocellulosic biomass based on various organic products, especially hardwood or various other products. organic products such as, for example, coconut, for the production of various bio-refining products, in particular ethanol and related products produced during the process.

The invention relates essentially to the pretreatment of organic products intended to achieve said biomass under optimal conditions both technically and economically, in order to obtain a quality bio-refining product, with optimal yield and implement this process by respecting strict rules of traceability of incoming materials in the process circuit to qualify the outgoing products from the process.

In this perspective, in particular, but also to ensure the best treatment of the material during the different successive stages of the process, it has proved essential to design a treatment process with "batches" or "batches", rather continuous processing and performing the various stages of cascade processing, knowing that each of the steps must take place following a previous step that generates one or more intermediate products. These intermediate products must, if necessary be separated or undergo one or more subsequent processing or transformation phases, before the final phase which allows the final product and possibly by-products and / or by-products to be isolated.

Since the volume of the raw material to be treated during the process evolves in the direction of a gradual reduction, because some additives, essential at the beginning of the process must be eliminated thereafter, the installation for the implementation of the process was designed on a modular basis to integrate the concept of volume variation in the process, to achieve a maximum standardized construction so as to avoid the costly steps of the "tailor-made" replaced by the possible multiplication of basic modules. Hence a construction of the cascade installation with standardized basic modules for each stage of the treatment, object of the process.

Fig. 1 is a general schematic view illustrating an embodiment of the plant 10 comprising all the stages of preparation of raw materials and their treatment with a view to producing a lignocellulosic biomass intended to supply bio-refining products and particular of ethanol. As mentioned earlier, batch work involves a finite supply of raw materials that will be called the initial mass. By way of example, this initial mass M0 may consist of the load transported by a certain number of transport vehicles 11, for example loaded with pre-sized particles of hardwood or with unmilled bulkwood. In the latter case, the bulk timber must be milled during a preliminary stage before starting any processing phase. Each carrier vehicle carries a fraction Mx of the initial mass M0, so that the sum of the fractions Mx supplied by the vehicles 11 represents the initial mass M0. The Mx fractions can be different from each other and they are precisely identified with respect to their origin, composition, characteristic, including residual moisture.

After a possible relatively fine grinding, for example by means of an attritor crusher, Mx fractions are then distributed by at least one loading device 12 in closed vessels called cookers 13 which will be described more in detail thereafter. The loading device 12 is intended to fill the cookers with batches of milled wood mixed with a predetermined volume of water. Since it is difficult to mix dry wood particles with a large volume of water, which in this case corresponds substantially to 75-90% of the total mass M1 of the mixture, the process provides for ensuring feeding the wood particles by an endless screw and carrying out the wood-water mixture in a hopper-shaped vessel, in which the water is injected preferably laterally by one or more approximately tangential jets to generate a swirling effect for to stir the mixture which flows through the base of the hopper directly into the cookers 13. The cookers 13 are all filled in the same way with substantially identical mixing volumes. The number of cookers 13 is chosen so that the whole wood-water mixture prepared from the initial mass M0 can be contained in said cookers 13. Because the temperature of the mixture must be brought to a value substantially between 160 and 200 ° C, the heating process is accelerated by injecting superheated steam such that the pressure in the cookers rises to a value between 500 and 2000 kPa during the treatment whose duration is between 10 and 120 min. For reasons of quality and efficiency of the process it is essential to ensure the PH of the mixture in the cookers. The pH value must be between 3.5 and 5 to avoid the development of fermentation inhibitors. The residence time of the mixture in the cooker 13 is between 20 and 120 minutes, depending on the composition of the initial mass M0.

The next lower stage of the cascade installation 10 comprises a series of expansion valves 14 or expansion vessels which receive the mass M2residuelle M1 mixture after its treatment in the cookers 13. The regulators 14 can evacuate the steam of water representing approximately 30% of the residual mass M2 of the mixture. At the output of the holders 14 is recovered a M3pâteuse mass having the consistency of molasses or sludge which is transferred to additional treatment tanks, for example pre-hydrolysis 15. This step can be carried out in the presence of enzymes during a period of the order of 6 to 12 hours in order to liquefy said mass M3pâteuse and obtain a kind of "liquor" residual M4. Apart from the pre-hydrolysis, other solutions are possible, in particular a bacterial treatment and / or a treatment with fungi that can be combined in the next fermentation step, thus reducing the total duration of the treatment.

When maintaining the pre-hydrolysis, the next step is to transfer the M4 mass liquor in fermentation tanks 16 to form said lignocellulosic biomass rich in C5 and C6 sugars. The residues of this enzymatic fermentation constitute said biomass M4. At this stage, the pretreatment of the initial mass material M0 is complete and the M4 biomass is ready for the final distillation stage in a distillation tower 16 which makes it possible, for example, to produce bioethanol or other bio-refining products as well as various by-products such as roasted wood pellets, for example, consisting essentially of the lignin contained in the initial mass M0.

When the fermentation phase in the presence of enzymes is replaced by a treatment in the presence of bacteria or in the presence of certain fungi, the process is faster and more effective than fermentation in the presence of enzymes to achieve the biomass M4destinine to be distilled.

FIG. 2 illustrates the cascade operating mode of the installation 10 and some specific details, such as the loading device which consists mainly of a hopper 12a and 12b feed means of wood particles or other organic materials. To avoid initial clogging of dry particles that would then be difficult to mix with the required volume of water, water inlets are provided, preferably in the form of lateral injectors, possibly tangential 12c, which have the particularity to create a swirling flow which facilitates the wetting of the wood, knowing that the volume of water to be added to the dry particles is of the order of 60 to 90% of the total mass to be treated.

The cookers 13 are equipped with a steam injector 13a to provide heat and pressure in the cooking vessel or cooker 13. The cooker is shown in more detail in FIG. 4.

FIG. 3 illustrates an attritor mill 12a, as used in the loading device 12. This type of mill, known per se, usually comprises a series of trays 12b equipped, at their end pads or grinding knives 12c, whose function is to project the particles of wood or other organic matter against a 12d cylindrical grid mounted inside a peripheral box 12e, to fractionate these particles, sort them by size through the perforations of the grids and for calibrate them. A calibration device (not shown) is usually associated with the mill for blowing off the particles and separating those that are not sized for recycling. The mill is mounted on a base 12l containing the transmission elements to the rotating parts and which carry a drive motor 12m whose output shaft is coupled to said transmission elements. The base 12l, the drive motor 12m and the transmission elements are suitable for the mill and constitute standard components that can be used for all the apparatuses of the installation which comprise a tank, a drive motor for driving parts. rotating and transmission elements.

FIG. 4 represents the cooker 13 which comprises a stirring device consisting of a pallet 13a or the like, rotating on a central vertical axis, having the effect of stirring the fluidized mass of material to be treated so as to raise it laterally along walls and make it go down to the center. The brewing being assured, we obtain a perfectly homogeneous mass. The material is discharged at the top of the cooker through an inlet E and is taken again after treatment with an outlet S. As mentioned above, it is associated with the cookers 13 of the installation comprising a rotary vane 13a, a base 131 and a motor 13m drive, for driving transmission elements to ensure the rotational drive of the pallet 13a, these components being standardized in order to simplify maintenance and minimize their cost.

The described installation is not limited to this embodiment, but could be modified without departing from the context of the present invention.

Claims (18)

Process for the preparation of lignocellulosic biomass based on various organic products, in particular wood or the like, for the production of bio-refinery products and in particular ethanol, in which at least one pretreatment phase of said organic products is successively carried out for producing said biomass, at least one complementary phase for preparing said biomass for fermentation, a fermentation phase and a final distillation phase for separating the bio-refinery and in particular ethanol products from the other substances resulting from the treatment of said products organic, in particular of wood or the like, characterized in that all the phases of the process are carried out on predetermined batches, in treatment units adapted to said batches, in that the critical parameters corresponding to each of the phases are adjusted. process for each of said predetermined batches by equipment combined with the x said units, and in that said pretreatment phase consists of a first step of preparation of a mixture of organic products, especially wood particles with a volume of water of between 75 and 90% of the mass of the mixture a second pressure cooking step of said mixture, at a temperature between 150 and 200 ° C, at a treatment pressure between 500 and 2000 kPa, and with a pH between 3.5 and 5, during a duration of between 10 and 120 min, of a third step of relaxing said mixture to evacuate the water vapor and recovering a mass forming a kind of molasses and at least a fourth complementary step in order to prepare the fermentation of said biomass prior to distillation. 2. Method according to claim 1, characterized in that said fourth complementary step to prepare the fermentation of said biomass is a pre-hydrolysis step in the presence of enzymes, this step having a duration of 6 to 12 hours in order to to liquefy said molasses by cutting the molecular chains to form a biomass rich in C5 and C6 sugars. 3. Method according to claim 1, characterized in that said complementary fourth step to prepare the fermentation of said biomass is a step of concentrating C5 and C6 sugars, in the presence of bacteria and / or fungi. 4. Method according to one of claims 1 to 3, characterized in that one determines the number of lots n1; n2; n3; n4; by initially defining the number n4 of pre-fermentation processing units corresponding to the n4lots to be treated in such a way that this number is sufficient to treat the molasses from the n3units of relaxation, then defining the number n3 of units of relaxation in such a way the total capacity of the said n3units of relaxation corresponding to n3lots to be treated is sufficient to treat n2lots from the cooking units, then defining the number n2de firing units such that the total capacity of said n2units cooking is sufficient to treat said n1lots of mixing from the mixing units. 5. Method according to claim 1, characterized in that said first step of preparing a mixture of organic products and said second step of firing said mixture, said pretreatment phase is carried out by simultaneously introducing said mass of organic products, in particular wood particles and water in a pressure cooking vessel with stirring means into which an appropriate volume of steam is injected to ensure the required rise in the temperature of the mixture and said treatment pressure. 6. Method according to claim 1, characterized in that said relaxation phase of said mixture for discharging water vapor and for recovering said molasses, is carried out in an expansion tank for releasing the pressure of the water vapor . 7. Method according to claim 2, characterized in that said fourth step of pre-hydrolysis in the presence of enzymes is carried out in a specific treatment tank into which said molasses resulting from the relaxation phase and said enzymes for to manufacture said biomass rich in C5 and C6 sugars. 8. A method according to claim 1, characterized in that, prior to said first phase of preparation of a mixture of organic products is carried out a grinding of organic products, including wood particles and a dosage of both the material dryer and additional water, said additional water being injected simultaneously with said dry material in said pressure cooking vessel, while mixing the mass to be treated. 9. Method according to one of the preceding claims, characterized in that said pre-hydrolysis of said lignocellulosic biomass is carried out in the presence of enzymes, bacteria or fungi. 10. Installation for the implementation of the process of an installation for the implementation of the process for the preparation and processing of a biomass based on various organic products, in particular wood particles, for the production of ethanol, comprising means for pretreatment of said organic products to produce said biomass, at least one equipment for performing a complementary phase of preparation for the fermentation of said biomass, equipment for carrying out a fermentation phase and finally a distillation tower for separating the bio-refinery and in particular ethanol products of the other substances resulting from the treatment of said organic products, in particular of wood or the like, characterized in that it comprises appropriate units for carrying out all the phases of the process on predetermined batches, in units adapted to said batches, specific control means for adjusting the parameters critical means corresponding to each of the phases of the process by equipment combined with said containers, means for distributing said batches in successive series disposed in cascade, each of said predetermined batches being disposed in one of said adapted units, and in that said pre-processing means of said organic products for producing said lignocellulosic biomass comprise at least one mixing and cooking vessel for the preparation of a mixture of organic products, in particular wood particles with a volume of water of between 75 and 90% of the mass of the mixture at least the pressure cooking of said mixture, at a temperature between 150 and 200 ° C, at a treatment pressure of between 500 and 2000 kPa, and with a pH of between 3.5 and 5, for a period of time between 10 and 120 min, at least one expansion vessel of said mixture for evacuating water vapor and recovering a pasty mass for a kind of molasses, at least one additional treatment tank to form a biomass rich in C5 and C6 sugars, these different units being arranged upstream of at least one fermentation tank followed by at least one distillation column. 11. Installation according to claim 10, characterized in that said complementary treatment tank is a pre-hydrolysis tank in the presence of enzymes for a treatment for a period of 6 to 12 hours in order to liquefy said molasses by cutting the chains. molecular. 12. Installation according to claim 10, characterized in that said complementary treatment tank is a treatment tank in the presence of bacteria and / or enzyme fungi for a treatment intended to liquefy said molasses by cutting the molecular chains. 13. Installation according to claim 10, characterized in that said pre-hydrolysis tank contains both enzymes, bacteria and / or fungi. 14. Installation according to claim 10 characterized in that it comprises a first series of n1unités of mixture arranged to prepare n1lots of mixed material; n2combustion units arranged to provide vapor pressure cooking and mixing of the mixed material from the mixing units; n3units of relaxation to relax by removing steam from mixing products from n2units of cooking and to produce a kind of molasses free of steam; and n4units of complementary preparation prior to the fermentation of said molasses. 15. Installation according to claim 12, characterized in that said n4unités complementary preparation are pre-hydrolysis vessels containing enzymes to produce the lignocellulosic biomass to be fermented and then subjected to distillation. 16. Installation according to claim 10, characterized in that said pressure cooking vessel comprises stirring means for circulating the mixture it contains according to lateral updrafts and in central axial downward currents and means for injecting a appropriate volume of water vapor to ensure the required rise in the temperature of the mixture and said treatment pressure inside the vessel. 17. Installation according to claim 10, characterized in that said stirring means comprise at least one rotary vane arranged horizontally at the bottom of the vessel and driven on an axis arranged vertically inside said vessel. 18. Installation according to claim 10, characterized in that it comprises at least one attritor mill mounted on a base which carries drive means and which contains transmission elements, said base, said drive means and said transmission elements constituting a predetermined mechanical unit adaptable to all parts of the installation comprising moving elements.