Production of monoethylene glycol

Abstract

A method for producing monoethylene glycol (MEG) from a wood-based raw material, the method comprising the steps of: i) providing a wood-based feedstock derived from the wood-based raw material and comprising wood chips, and subjecting the wood-based feedstock to at least one pretreatment to form a liquid fraction and a fraction comprising solid cellulose particles, wherein at most 5 wt.% of the wood chips in the wood-based feedstock are excess thickness wood chips as defined by SCAN-CM 40:01; ii) subjecting the fraction comprising solid cellulose particles to enzymatic hydrolysis to form a lignin fraction and a carbohydrate fraction; iii) subjecting the carbohydrate fraction to catalytic conversion to form a liquid glycol composition; and iv) recovering monoethylene glycol from the liquid glycol composition. Also disclosed are corresponding configurations and monoethylene glycol obtained by the method.

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing monoethylene glycol (MEG) from wood-based feedstock. The disclosure further relates to an arrangement for producing monoethylene glycol (MEG) from wood-based feedstock. The disclosure further relates to monoethylene glycol obtained by the method described herein. [Background technology]

[0002] Monoethylene glycol (MEG), also known as ethylene glycol or 1,2-ethanediol, is an important liquid raw material that finds use in the production of, for example, polyethylene terephthalate (PET) and polyester resins. Monoethylene glycol can be used in applications requiring chemical intermediates for resins, solvent couplers, freezing point depressants, solvents, wetting agents, and chemical intermediates. The increasing use of monoethylene glycol in the polyester fiber and polyethylene terephthalate industries is driving the growth of the global monoethylene glycol market. Conventional methods for producing ethylene glycol involve the use of non-renewable resources. Therefore, the present inventors recognized the need to provide a method for producing monoethylene glycol using bio-based materials. Summary of the Invention

[0003] A method for producing monoethylene glycol from a wood-based (wood-based) raw material is disclosed. The method may include: i) providing a wood-based feedstock derived from the wood-based raw material and comprising wood chips; and subjecting the wood-based feedstock to at least one pretreatment to form a liquid fraction and a fraction comprising solid cellulose particles, wherein at most 5% by weight of the wood chips in the wood-based feedstock are excess thickness wood chips as defined by SCAN-CM 40:01. The method may further include ii) subjecting the fraction comprising solid cellulose particles to enzymatic hydrolysis to form a lignin fraction and a carbohydrate fraction. The method may further include iii) subjecting the carbohydrate fraction to catalytic conversion to form a liquid glycol composition. The method may further include iv) recovering monoethylene glycol from the liquid glycol composition.

[0004] Also disclosed is an arrangement for producing monoethylene glycol from a wood-based raw material. The arrangement may include at least one pretreatment section configured to subject a wood-based feedstock derived from the wood-based raw material and including wood chips to at least one pretreatment to form a liquid fraction and a fraction including solid cellulose particles, wherein at most 5% by weight of the wood chips in the wood-based feedstock are over-thickness wood chips as defined by SCAN-CM 40:01. The arrangement may further include at least one hydrolysis reactor configured to subject the fraction including solid cellulose particles to enzymatic hydrolysis to form a lignin fraction and a carbohydrate fraction. The arrangement may further include a conversion reactor configured to subject the carbohydrate fraction to catalytic conversion to form a liquid glycol composition. The arrangement may further include a distillation section configured to recover monoethylene glycol from the liquid glycol composition.

[0005] Further disclosed is monoethylene glycol produced by the methods described herein. [Brief explanation of the drawings]

[0006] The accompanying drawings, which are included to provide a further understanding of the embodiments and constitute a part of this specification, illustrate various embodiments.

[0007] [Figure 1] FIG. 1 provides a flow chart of one embodiment of a process for producing monoethylene glycol. [Figure 2] FIG. 2 presents one embodiment of an arrangement for producing monoethylene glycol. [Figure 3] Figure 3 shows the chip classifier presented in SCAN-CM 40:01. [Figure 4] FIG. 4 presents measurements made when measuring the geometric specific surface area (GSSA). [Figure 5] FIG. 5 presents measurements made when measuring the geometric specific surface area (GSSA). DETAILED DESCRIPTION OF THE INVENTION

[0008] A method for producing monoethylene glycol (MEG) from wood-based raw materials is disclosed. The method comprises: i) providing a wood-based feedstock derived from a wood-based raw material and comprising wood chips, and subjecting the wood-based feedstock to at least one pretreatment to form a liquid fraction and a fraction comprising solid cellulose particles, wherein at most 5% by weight of the wood chips in the wood-based feedstock are excess thickness wood chips as defined by SCAN-CM 40:01; ii) subjecting the solid cellulose particle-containing fraction to enzymatic hydrolysis to form a lignin fraction and a carbohydrate fraction; iii) subjecting the carbohydrate fraction to catalytic conversion to form a liquid composition of glycols; iv) recovering monoethylene glycol from the liquid glycol composition; may include:

[0009] Additionally, an arrangement (apparatus) for producing monoethylene glycol (MEG) from wood-based feedstock is disclosed, the arrangement comprising: at least one pre-treatment unit configured to subject a wood-based feedstock derived from a wood-based raw material and comprising wood chips to at least one pre-treatment to form a liquid fraction and a fraction comprising solid cellulose particles, wherein at most 5 wt.% of the wood chips in the wood-based feedstock are excess thickness wood chips as defined by SCAN-CM 40:01; at least one hydrolysis reactor configured to subject the solid cellulose particle-containing fraction to enzymatic hydrolysis to form a lignin fraction and a carbohydrate fraction; a conversion reactor configured to subject the carbohydrate fraction to catalytic conversion to form a liquid composition of glycols; a distillation section configured to recover monoethylene glycol from said glycol liquid composition; may include:

[0010] Further disclosed is monoethylene glycol (MEG) obtainable by the methods described herein.

[0011] The expression "pretreating" or "pretreatment" in this specification, unless otherwise specified, should be understood as (a) a process carried out to convert wood-based feedstock into a fraction containing solid cellulose particles. As a result of the pretreatment, a liquid fraction may be formed in addition to the fraction containing solid cellulose particles. The liquid fraction may be separated from the fraction containing solid cellulose particles. The fraction containing solid cellulose particles may further contain a certain amount of lignocellulose particles and lignin particles in free form. Lignocellulose contains lignin chemically bound to cellulose particles. Wood-based raw materials are , hardwood, softwood, and combinations thereof. The wood-based raw material may be derived from, for example, pine, poplar, beech, aspen, spruce, eucalyptus, ash, or birch. The wood-based raw material may be any combination or mixture thereof. The wood-based raw material may be hardwood. Preferably, the wood-based raw material is hardwood due to its relatively high inherent sugar content, although the use of other types of wood is not excluded. The hardwood may be selected from the group consisting of beech, birch, ash, oak, maple, chestnut, willow, poplar, and any combination or mixture thereof.

[0012] Providing the wood-based raw material in step i) may include subjecting the wood-based raw material to a mechanical treatment selected from debarking, chipping, splitting, cutting, beating, crushing, crushing, splitting, sieving, and / or washing the wood-based raw material to form the wood-based feedstock.

[0013] The arrangement may include a machine configured to subject the wood-based raw material to a mechanical treatment selected from debarking, chipping, splitting, cutting, beating, crushing, crushing, splitting, sieving, and / or washing the wood-based raw material to form the wood-based feedstock.

[0014] Thus, providing a wood-based feedstock derived from a wood-based raw material may include subjecting the wood-based raw material to mechanical processing to form the wood-based feedstock. This mechanical processing may include debarking, chipping, splitting, cutting, beating, crushing, crushing, splitting, sieving, and / or washing the wood-based raw material. During the mechanical processing, for example, the bark of a log can be removed and / or wood chips of a specific size and structure can be formed. The formed wood chips can also be washed, for example, with water, to remove, for example, sand, pebbles, and stones therefrom. Furthermore, the structure of the wood chips can be relaxed before the pre-treatment step. The wood-based feedstock may contain a certain amount of bark from the log.

[0015] Providing the wood-based feedstock may include purchasing the wood-based feedstock. The purchased wood-based raw material may include purchased wood chips or sawdust derived from the wood-based raw material.

[0016] In one embodiment, the specific surface area (SSA) of the wood chips is between 2 and 35 cm 2 / g, or 4 to 33 cm 2 / g, or 6 to 30 cm 2 / g, or 10 to 25 cm 2 / g, or 12 to 20 cm 2 / g.

[0017] The specific surface area (SSA) of wood chips can be measured by applying water to the surface of the wood chip pieces and measuring the mass of this water (SSA measured by liquid adsorption). Based on the mass of water applied, it is possible to calculate the average specific surface area of ​​the chip pieces per specific mass of dry matter. The chips are soaked before measurement to reach the cell wall saturation point. This prevents the applied water from being absorbed into the wood material. After soaking, the surfaces of the wood chip pieces are dehydrated by centrifugation. The mass of the centrifuged wood chip pieces is then weighed. The wood chip pieces are then immersed in water, forming a water film on the surface of the chip pieces. The moistened chip pieces are then reweighed. The mass of the added water can be calculated from the difference between the mass of the wood chip pieces with the dry surface and the mass of the wood chip pieces coated with the water film. The wood chip pieces are then dried to determine the amount of dry matter in the sample. The specific surface area is calculated based on the ratio of the mass of water applied to the surface of the wood chip pieces to the amount of dry matter in the wood chip pieces. This calculation is performed using the formula presented below. Therefore, the specific surface area may be determined as follows: A well-mixed sample is weighed in a metal basket at a wet weight of 100 g. The numbered metal baskets are placed in a plastic bucket filled with water at room temperature. Ensure that all chips are below the water surface. The sample is soaked for at least 8 hours, most preferably overnight, to allow the wood cell walls and cell lumens to fill with water. This prevents water from being absorbed by the chips later, which would affect the specific surface area result. After soaking, the sample is placed in a standard moisture centrifuge bag. The moisture content of the centrifuge bag is standardized by immersing the bag in water and centrifuging it for 2 minutes before each sample point. The sample is centrifuged for 4 minutes. The sample is weighed in the basket to an accuracy of 0.01 g (weight 1). The weighing result is recorded. The weighed sample is then re-immersed in water for 2 minutes, ensuring that all chips are submerged. After this, the sample is placed in the basket over the bucket and drained for 30 seconds. Transfer the wet chips to a tared drying container and weigh to the nearest 0.01 g (Weight 2) and record the weighing result. Dry the sample overnight in a heat cabinet at 105±2°C. After drying, weigh the sample (Weight 3).The weighing result is recorded. The result is calculated using the following formula g. 水 / g od_木材 (grams of water added per gram of dry matter).

number

[0018] The result is calculated as the average of two parallel measurements. By calculation, the result is converted to grams of water added per gram of dry matter. 水 / g od_木材 ) is converted to specific surface area (SSA) according to the following formula:

number

[0019] In one embodiment, the geometric specific surface area (GSSA) of the wood chips is between 4 and 40 cm 2 / g, or 5 to 35 cm 2 / g, or 6 to 30 cm 2 / g, or 10 to 25 cm 2 / g, or 12 to 20 cm 2 / g.

[0020] The geometric specific surface area (GSSA) may be measured as follows: First, the size distribution of the wood chips is measured according to SCAN-CM 40:01.

[0021] [Table 1]

[0022] Next, 50 wood chips are randomly selected from each allowable fraction, and the following dimensions of each wood chip are measured as shown in Figure 4: The mass-weighted average length and width of the wood chips in each fraction is measured in accordance with SCAN-CM 48:01 (revised 2001). The wood chips are sorted into 15 classes within each fraction, and the mass-weighted average length and width is calculated.

[0023] [Table 2]

[0024] [Table 3]

[0025] The wood chip thickness of each wood chip is then measured to an accuracy of 0.1 mm, and the wood chips are classified into 15 classes, namely T1, T2, ... T15, from thinnest to thickest, and the thickness average and mass weight of each class are calculated as in SCAN-CM 48:01. The mass-weighted average of thickness is calculated.

[0026] The cutting angles of 10 tips from each fraction are then measured and the average angle, An, is calculated.

[0027] The angle of each wood chip is then measured by taking a wood chip, drawing the cut angle on paper, lengthening the sides of the angle to form a right triangle (the larger the more accurate), measuring the opposite face and hypotenuse of the triangle, and calculating, as presented in Figure 5. Angle from the formula An=arcsin(A / B) The geometric specific surface area (GSSA) of each fraction can then be calculated by the following formula: GSSAn=20000×(Wn×Ln+Tn×Ln+Wn×Tn / sin(An)) / (Ln×Wn×Tn×BD) In the above formula, GSSAn = specific surface area of ​​fraction Fn [cm 2 / g] Wn = mass-weighted average tip width in fraction Fn [mm] Ln = mass-weighted average tip length in fraction Fn [mm] Tn = mass-weighted average chip thickness in fraction Fn [mm] An = average cutting angle of the tip in each fraction Fn [radian] BD = bulk density of wood [kg dry wood / solid m of wet wood] 3 ]

[0028] The mass weighted average geometric specific surface area (GSSA) can then be calculated by the following formula: GSSA=(Σ(SSAn×Fn)) / 100 In the above formula, GSSA = Geometric specific surface area of ​​chip GSSAn = mass-weighted average of the geometric specific surface area of ​​fraction Fn [cm 2 / g] Fn = mass fraction of each size of chips classified according to standard SCAN-CM 40:01

[0029] Wood-based feedstock may contain wood chips, and at most 5% by weight of the wood chips in this wood-based feedstock are over-thickness wood chips as defined by SCAN-CM 40:01. Standard SCAN-CM 40:01 (revised 2001) describes a method for sorting wood chips in which a sample of wood chips is placed on the top screen of a stack of five screen trays and a fines tray (see Figure 3). The screens have holes or slots of specific dimensions, and the stack is held in a reciprocating motion. After a specified time, sieving is stopped, and the resulting six classes are weighed separately. The size of each class is its mass, expressed as a percentage of the total mass of all six classes.

[0030] In this specification, unless otherwise specified, the characterization of wood chips in a wood-based feedstock as "over-thick wood chips" should be understood as wood chips that pass through the first screen of a chip classifier but are retained on the second screen with 8 mm slots when chip size classification is performed as specified in SCAN-CM 40:01.

[0031] In this specification, unless otherwise specified, the characterization of wood chips in wood-based raw materials as "fines" should be understood as wood chips that are not retained on a fifth screen with 3 mm holes when chip size classification is performed as specified in SCAN-CM 40:01.

[0032] In one embodiment, at most 3.5% by weight, or at most 3% by weight, or at most 2.5% by weight, or at most 2% by weight of the wood chips in the wood-based feedstock are over-thickness wood chips as defined by SCAN-CM 40:01.

[0033] In one embodiment, at most 10% by weight, or at most 6% by weight, or at most 3% by weight, or at most 1.5% by weight, or at most 0.5% by weight of the wood chips in the wood-based feedstock are fines as defined by SCAN-CM 40:01.

[0034] In one embodiment, at most 3% by weight, or at most 1% by weight, or at most 0.5% by weight, or at most 0.1% by weight, or essentially 0% by weight of the wood chips in the wood-based feedstock are oversized wood chips as defined by SCAN-CM 40:01. That is, the oversized wood chips may be essentially removed from the wood-based feedstock. In this specification, the characterization of wood chips in a wood-based raw material as "oversized wood chips" should be understood as wood chips that do not pass through a first screen with 45 mm holes when chip size classification is performed as defined in SCAN-CM 40:01, unless otherwise specified.

[0035] The inventors have surprisingly found that impregnation liquid is more uniformly absorbed into and impregnated into a feedstock containing wood chips of a particular size, particularly when the amount of oversized wood chips is minimized and the amount of over-thickness wood chips in the feedstock is controlled.

[0036] The pretreatment of the wood-based feedstock in step i) may involve one or more different pretreatment processes. During the different pretreatment processes, the wood-based feedstock is varied accordingly. The purpose of at least one pretreatment process is to form a fraction containing solid cellulose particles for further processing.

[0037] Pretreatment i) may include subjecting the wood-based feedstock to a pre-steaming treatment. Pretreatment i) may include subjecting the wood-based feedstock received from the mechanical treatment to a pre-steaming treatment. The pretreatment in i) may include impregnation and / or steam explosion, and may include subjecting the wood-based feedstock to a pre-steaming treatment before subjecting the wood-based feedstock to the impregnation and / or steam explosion. The pre-steaming of the wood-based feedstock is carried out using steam having a temperature of 100 to 130°C at atmospheric pressure. During the pre-steaming treatment, the wood-based feedstock is treated with low-pressure steam. Pre-steaming may also be carried out using steam having a temperature of less than 100°C, or less than 98°C, or less than 95°C. Pre-steaming has the additional benefit of reducing or removing air from the interior of the wood-based feedstock.

[0038] The pre-steaming may occur in at least one pre-steaming reactor. In one embodiment, one of the at least one pre-treatment unit is a pre-steaming reactor configured to subject the wood-based feedstock to pre-treatment. In one embodiment, one of the at least one pre-treatment unit is a pre-steaming reactor operatively disposed before the impregnation reactor and / or the pressurized reactor and configured to subject the wood-based feedstock to pre-steaming with steam having a temperature of 100-130°C at atmospheric pressure.

[0039] Furthermore, the pretreatment in i) may comprise subjecting the wood-based raw material to at least one impregnation treatment with an impregnation liquid. This impregnation treatment may be carried out on wood-based feedstock received from mechanical treatment and / or from a prior steam treatment. The pretreatment in i) may comprise subjecting the wood-based feedstock to at least one impregnation treatment with an impregnation liquid selected from water, at least one acid, at least one alkali, at least one alcohol, or any combination or mixture thereof, prior to steam explosion.

[0040] The present inventors have surprisingly found that a specific size range of wood chips in a wood-based feedstock has the additional benefit of beneficially influencing the impregnation process. Surprisingly, it has been found that when wood chips of a specific size are used, the impregnation liquid can be more evenly distributed and absorbed by the wood chips.

[0041] The wood-based feedstock may be transferred from the mechanical treatment and / or pre-steam treatment to the impregnation treatment using a feeder. The feeder may be a screw feeder, such as a plug screw feeder. The feeder may compress the wood-based feedstock during transport. When the wood-based feedstock then enters the impregnation treatment, it may expand and absorb the impregnation liquid.

[0042] The impregnation solution may contain water, at least one acid, at least one alkali, at least one alcohol, or any combination or mixture thereof. The at least one acid may be selected from the group consisting of inorganic acids such as sulfuric acid (H2SO4), nitric acid, and phosphoric acid, organic acids such as acetic acid, lactic acid, formic acid, and carbonic acid, and any combination or mixture thereof. In one embodiment, the impregnation solution contains sulfuric acid, for example, dilute sulfuric acid. The acid concentration may be 0.3 to 5.0% w / w, 0.5 to 3.0% w / w, 0.6 to 2.5% w / w, 0.7 to 1.9% w / w, or 1.0 to 1.6% w / w. The impregnation solution may act as a catalyst to influence the hydrolysis of hemicellulose in the wood-based feedstock. In one embodiment, impregnation is carried out using only water, i.e., by autohydrolysis. In one embodiment, the wood-based feedstock may be impregnated by alkaline hydrolysis. NaOH and Ca2(OH)3 are examples of alkalis used in alkaline hydrolysis.

[0043] One of the at least one pre-treatment section may be an impregnation reactor configured to subject the wood-based raw material to at least one impregnation treatment with an impregnation liquid. One of the at least one pre-treatment section may be an impregnation reactor operably disposed before the pressurized reactor and configured to subject the wood-based feedstock to at least one impregnation treatment with an impregnation liquid selected from water, at least one acid, at least one alcohol, or any combination or mixture thereof. Thus, the impregnation treatment may occur in at least one impregnation reactor or impregnation vessel. In one embodiment, two or more impregnation reactors are used.

[0044] The transfer from one impregnation reactor to another may be performed using a feeder, such as a screw feeder, which may eliminate the liquid concentration difference within the wood chips along with the steam, allowing the impregnation liquid to penetrate the wood chips more easily.

[0045] The impregnation process may be carried out by conveying the wood-based raw material through at least one impregnation reactor, i.e., the wood-based raw material is transferred to the impregnation reactor, interspersed within the impregnation reactor, and removed from the impregnation reactor so that the wood-based raw material is homogeneously impregnated with the impregnation liquid. The impregnation process may be carried out as a batch process or continuously.

[0046] The residence time of the wood-based feedstock in the impregnation reactor, i.e., the time the wood-based feedstock is in contact with the impregnation liquid, may be from 5 seconds to 5 minutes, or from 0.5 to 3 minutes, or about 1 minute. The temperature of the impregnation liquid may be, for example, from 20 to 99°C, or from 40 to 95°C, or from 60 to 90°C. Maintaining the temperature of the impregnation liquid below 100°C has the added benefit of preventing or reducing dissolution of hemicellulose.

[0047] After the impregnation treatment, the wood-based feedstock may be held for a predetermined time, for example in a storage tank or silo, to allow the impregnation solution absorbed by the wood-based feedstock to stabilize, which may be 15 to 60 minutes, or for example about 30 minutes.

[0048] Pretreatment i) may include subjecting the wood-based feedstock to steam explosion. The wood-based feedstock from the mechanical treatment, pre-steaming step, and / or impregnation treatment may be subjected to steam explosion. In one embodiment, pretreatment i) includes at least one of mechanical treatment of the wood-based material to form the wood-based feedstock, pre-steaming of the wood-based feedstock, impregnation of the wood-based feedstock, and steam explosion of the wood-based feedstock. In one embodiment, pretreatment i) includes mechanical treatment of the wood-based material to form the wood-based feedstock, pre-steaming of the wood-based feedstock, impregnation of the wood-based feedstock, and steam explosion of the wood-based feedstock. In one embodiment, pretreatment i) includes pre-steaming of the wood-based feedstock, impregnation of the wood-based feedstock, and steam explosion of the wood-based feedstock. In one embodiment, pretreatment i) includes impregnation of the wood-based feedstock, and steam explosion of the wood-based feedstock. That is, the wood-based feedstock may be subjected to an impregnation treatment and then steam explosion, or the wood-based feedstock may be subjected to a pre-steam treatment and then impregnation, after which the impregnated wood-based feedstock may be subjected to steam explosion.

[0049] The wood-based feedstock can be stored, for example, in chip bins or silos between different treatments, or it can be transported in a continuous manner from one treatment to another.

[0050] The pretreatment in i) may include subjecting the wood-based feedstock to steam explosion, which is carried out by treating the wood-based feedstock with steam having a temperature of 130-240°C under a pressure of 0.17-3.25 MPaG, followed by a sudden explosive decompression of the wood-based feedstock. The wood-based feedstock may be treated with steam for 1-20 minutes, or 1-20 minutes, or 2-16 minutes, or 4-13 minutes, or 3-10 minutes, or 3-8 minutes prior to the sudden explosive decompression of the wood-based feedstock.

[0051] As used herein, the term "steam explosion" may refer to a process of hemihydrolysis in which wood-based feedstock is treated in a reactor with steam having a temperature of 130-240°C under a pressure of 0.17-3.25 MPaG, followed by a sudden explosive decompression of the wood-based feedstock, resulting in rupture of the fibrous structure of the wood-based feedstock.

[0052] The steam explosion process may be carried out in a pressurized reactor. That is, one of the at least one pretreatment units may be a pressurized reactor configured to subject a wood-based feedstock derived from a wood-based raw material to steam explosion. Steam explosion may be carried out in the pressurized reactor by treating the wood-based feedstock with steam having a temperature of 130 to 240°C under a pressure of 0.17 to 3.25 MPaG, followed by a sudden explosive decompression of the wood-based feedstock. The wood-based feedstock may be introduced into the pressurized reactor using a compression conveyor, such as a screw feeder. When a screw feeder is used, a portion of the impregnation liquid absorbed by the wood-based feedstock is removed as a pressate during transport by the screw feeder, while a portion remains in the feedstock. The wood-based feedstock may be introduced into the pressurized reactor together with steam and / or gas. The pressure of the pressurized reactor can be controlled by adding steam. The pressurized reactor may be operated in a continuous manner or as a batch process. The wood-based feedstock, e.g., a wood-based feedstock that has been subjected to an impregnation treatment, may be introduced into the pressure reactor at a temperature of 25 to 140°C. The residence time of the wood-based feedstock in the pressure reactor may be 0.5 to 120 minutes. The term "residence time" as used herein, unless otherwise specified, should be understood as the time between the wood-based feedstock, e.g., being introduced into or entering the pressure reactor, and the wood-based feedstock leaving or being discharged from the pressure reactor.

[0053] As a result of the semi-hydrolysis of the wood-based feedstock affected by the steam treatment in the reactor, hemicellulose present in the wood-based feedstock may be hydrolyzed or decomposed into, for example, oligomers and / or monomers of xylose. Thus, steam explosion of the wood-based feedstock may result in the formation of an output stream. The output stream from steam explosion may be subjected to gas-liquid separation. The output stream from steam explosion may be mixed or combined with a liquid. The output stream from steam explosion may be mixed with a liquid to form a liquid fraction and a fraction containing solid cellulose particles. This liquid may be pure water or water containing C5 sugars. The water containing C5 sugars may be recycled water from separating and / or washing the fraction containing solid cellulose particles prior to enzymatic hydrolysis. The output stream may be mixed with the liquid, and the resulting mass may be mechanically homogenized to break down agglomerates.

[0054] The liquid fraction may contain sugars from hydrolyzed hemicellulose, as well as soluble lignin and other by-products. In one embodiment, the liquid fraction contains carbohydrates, such as C5 sugars (CH 10 O5 or (C5(H2O) n The liquid fraction contains carbohydrates, such as monosaccharides (CH 12 O6 or C5H 10 O5), disaccharide (C 12 H 22 O 11 ), oligosaccharides and / or polysaccharides ((CH 10 O5) n or (C5H8O4) n In one embodiment, the liquid fraction may contain soluble C5 carbohydrates (C5H 10 O5 or C5 (H2O) n ) and other carbohydrates. The liquid fraction may also contain other components.

[0055] The fraction containing solid cellulose particles may contain lignin in addition to cellulose. In one embodiment, the fraction containing solid cellulose particles contains carbohydrates, such as solid C6 carbohydrates (CH 12 O6 or C6(H2O) n), and lignin. The fraction containing solid cellulose particles may also contain other carbohydrates and other components.

[0056] The method may include, prior to step ii), separating and recovering the liquid fraction formed in step i) and a fraction containing solid cellulose particles. The separated or recovered fraction containing solid cellulose particles may be washed before being subjected to enzymatic hydrolysis in step ii). The fraction containing solid cellulose particles may be diluted with water and / or another liquid containing at least soluble carbohydrates.

[0057] Step ii) of subjecting the fraction containing solid cellulose particles to enzymatic hydrolysis may be carried out at a temperature of 30 to 70°C, or 35 to 65°C, or 40 to 60°C, or 45 to 55°C, or 48 to 53°C. Step ii) of subjecting the fraction containing solid cellulose particles to enzymatic hydrolysis may be carried out at atmospheric pressure. The pH of the fraction containing solid cellulose particles may be maintained at a pH value of 3.5 to 6.5, or 4.0 to 6.0, or 4.5 to 5.5 during step ii). The pH of the fraction containing solid cellulose particles may be adjusted by adding alkali and / or acid. Step ii) of subjecting the fraction containing solid cellulose particles to enzymatic hydrolysis may last for 20 to 120 hours, or 30 to 90 hours, or 40 to 80 hours. The enzymatic hydrolysis of the fraction containing solid cellulose particles may be carried out in a continuous manner, as a batch process, or as a combination of continuous and batch processes.

[0058] In one embodiment, the enzymatic hydrolysis is carried out at a temperature of 30 to 70°C, or 35 to 65°C, or 40 to 60°C, or 45 to 55°C, or 48 to 53°C, while maintaining the pH of the fraction containing the solid cellulose particles at a pH value of 3.5 to 6.5, or 4.0 to 6.0, or 4.5 to 5.5, and the enzymatic hydrolysis is continued for 20 to 120 hours, or 30 to 90 hours, or 40 to 80 hours.

[0059] Enzymatic hydrolysis may be carried out in at least one process step.

[0060] In one embodiment, enzymatic hydrolysis can be carried out as a single-stage hydrolysis process, in which the fraction containing solid cellulose particles is subjected to enzymatic hydrolysis in at least one first hydrolysis reactor. After hydrolysis, the hydrolysis product, i.e., the hydrolysate, can be subjected to separation, in which the solid lignin fraction, which may contain unhydrolyzed cellulose in addition to lignin, is separated from the liquid carbohydrate fraction. The single-stage hydrolysis process can be carried out as a batch process, for example, with several reactors operating in parallel, each of which can receive a portion of the fraction containing solid cellulose particles. Furthermore, separate parallel lines with parallel reactors can be used.

[0061] In one embodiment, the enzymatic hydrolysis may be carried out as a two-stage or multi-stage hydrolysis process. In the two-stage or multi-stage hydrolysis process, a fraction containing solid cellulose particles may first be subjected to a first enzymatic hydrolysis in at least one first hydrolysis reactor. The formed liquid carbohydrate fraction may then be separated from a solid lignin fraction, which may also contain unhydrolyzed cellulose. The solid fraction may then be subjected to a second or any subsequent enzymatic hydrolysis, for example, in at least one second hydrolysis reactor. At least one of the first enzymatic hydrolysis and the second or any subsequent enzymatic hydrolysis may be carried out as a batch process or as a continuous process, for example, including one or more reactors operating in parallel. After the second or any subsequent enzymatic hydrolysis, the hydrolysis product, i.e., hydrolysate, may be subjected to separation, in which the solid lignin fraction is separated from the liquid carbohydrate fraction.

[0062] The reaction time in the first hydrolysis reactor may be from 8 to 72 hours. The reaction time in the second and / or any subsequent hydrolysis reactors may be from 8 to 72 hours.

[0063] The enzyme is a catalyst for enzymatic hydrolysis. The enzymatic reaction may lower the pH and reduce the viscosity by shortening the length of the cellulose fibers. The fraction containing solid cellulose particles may be subjected to enzymatic hydrolysis, resulting in the enzymatic conversion of cellulose to glucose monomers. The lignin present in the fraction containing solid cellulose particles may remain essentially in a solid form.

[0064] To carry out the enzymatic hydrolysis, at least one enzyme may be used. The at least one enzyme may be selected from the group consisting of cellulases, hemicellulases, laccases, and lignolytic peroxidases. Cellulases are multiprotein complexes consisting of synergistic enzymes with different specific activities that can be divided into exo- and endo-cellulases (glucanases) and β-glucosidases (cellobioses). The enzymes may be commercially available cellulase mixtures or may be produced in-situ.

[0065] Cellulose is an insoluble linear polymer of repeating glucose units linked by β-1-4-glucosidic bonds. During enzymatic hydrolysis, the cellulose chains are broken by cleaving at least one β-1-4-glucosidic bond.

[0066] Enzymatic hydrolysis may result in the formation of a lignin fraction and a carbohydrate fraction. In one embodiment, the carbohydrate fraction is composed of C6 sugars (CH 12 O6 or (C6(H2O) n In one embodiment, the carbohydrate fraction comprises monosaccharides (CH 12 O6 or C5H 10 O5), disaccharide (C 12 H 22 O 11 ), oligosaccharides, and / or polysaccharides ((CH 10 O5) n or (C5H8O4) nIn one embodiment, the carbohydrate fraction comprises galactose, glucose, mannose, arabinose, xylose, glucuronic acid and / or galacturonic acid.

[0067] The present inventors have surprisingly found that the particular size range of wood chips in a wood-based feedstock has the additional benefit of influencing the amount of carbohydrate fraction received from enzymatic hydrolysis.

[0068] In one embodiment, the lignin fraction is in solid form. In one embodiment, the carbohydrate fraction is in liquid form. The lignin and carbohydrate fractions formed in ii) may be separated and recovered prior to iii).

[0069] During the separation carried out before ii) and / or iii), the solid fraction may be separated from the liquid fraction. The separation carried out before ii) and / or iii) may be carried out by filtration and / or centrifugation. The filtration may be vacuum filtration, filtration based on the use of low pressure, filtration based on the use of excess pressure, or a filter press.

[0070] The carbohydrate fraction recovered from the enzymatic hydrolysis may be purified prior to step iii). Purification of the carbohydrate fraction may be carried out by using at least one of the following methods: membrane filtration, crystallization, sterilization, pasteurization, evaporation, chromatography, ion exchange, activated carbon. Purification of the carbohydrate fraction has the additional benefit of providing sugars of a desired target quality. The carbohydrate fraction may be subjected to catalytic conversion in iii).

[0071] The catalytic conversion of the carbohydrate fraction iii) may comprise subjecting the carbohydrate fraction to catalytic hydrocracking. That is, the carbohydrate fraction may be exposed to a catalyst in the presence of hydrogen in step iii). The catalytic conversion may be carried out in the presence of water. In one embodiment, the catalytic conversion of the carbohydrate fraction comprises subjecting the carbohydrate fraction to catalytic hydrogenation in the presence of a solvent, preferably water, and a catalyst system.

[0072] The catalytic conversion may be carried out in the presence of a catalyst system comprising one or more catalysts. In one embodiment, the catalyst system comprises or consists of a first catalyst. In one embodiment, the catalyst system comprises or consists of at least a first catalyst and at least a second catalyst. In one embodiment, the catalyst system comprises or consists of a first catalyst and a second catalyst. The first catalyst may be a heterogeneous solid catalyst. The second catalyst may be a homogeneous catalyst. In one embodiment, the first and second catalysts may be heterogeneous catalysts, for example, supported on a carrier.

[0073] The first catalyst may comprise an active metal component selected from Groups 8, 9, or 10 of the IUPAC Periodic Table of Elements, such as iron, cobalt, nickel, ruthenium, rhodium, palladium, iridium, and platinum, or mixtures thereof. In one embodiment, the first catalyst comprises or consists of a heterogeneous Ni alloy, such as Raney nickel. The active metal component of the first catalyst may be supported by a support comprising activated carbon, alumina, silica, silicon carbide, zirconia, zinc oxide, titanium dioxide, or mixtures thereof. The active metal component of the first catalyst may comprise 0.05 to 70 wt. % of the total weight of the catalyst.

[0074] The second catalyst may comprise at least one active component selected from tungsten oxide, tungsten sulfide, tungsten hydroxide, tungsten bronze oxide, tungstic acid, tungstate, metatungstic acid, metatungstate, paratungstic acid, paratungstate, peroxotungstic acid, pertungstate, and tungsten-containing heteropolyacid. In one embodiment, the second catalyst comprises or consists of homogeneous sodium tungstate.

[0075] The first catalyst may be active in hydrogenation, and the second catalyst may be active in cracking (decomposition).

[0076] In one embodiment, the second catalyst is a homogeneous catalyst, and the second catalyst may be recovered, recycled, and reused in iii).

[0077] The catalytic conversion of the carbohydrate fraction in step iii) may be carried out at a temperature of 120 to 300°C, or 180 to 270°C, or 230 to 270°C. The initial pressure at room temperature in iii) may be 1 to 15 MPa, or 9 to 12 MPa. The catalytic conversion may be carried out continuously. The time for which the carbohydrate fraction is subjected to catalytic conversion may be 5 minutes to 3 hours, or 30 minutes to 2.5 hours.

[0078] The catalytic conversion may be carried out in a conversion reactor, such as a fixed-bed reactor or a slurry reactor. The catalytic conversion of the carbohydrate fraction may occur as a slurry reaction. Hydrogen and the carbohydrate fraction may be added to the reactor separately or simultaneously using their respective pumps and compressors. A second catalyst in liquid form may be added to the reactor separately or simultaneously with the carbohydrate fraction. The first catalyst may be fed to the reactor separately from the carbohydrate fraction, preferably before the carbohydrate fraction is fed to the reactor. Liquid and gaseous reaction products, including glycols, may be removed from the reactor. The reaction products may be cooled and depressurized. After depressurization, the gaseous products may be subjected to gas / liquid separation to separate the product, including glycols, in liquid form.

[0079] Thus, a liquid glycol composition may be obtained by subjecting the carbohydrate fraction to catalytic conversion iii). The catalytic conversion accomplishes at least hydrogenation and hydrocracking reactions to hydrogenate and hydrocracking the carbohydrate fraction to form a liquid glycol composition. The liquid glycol composition may comprise or consist of monoethylene glycol (MEG, also known as 1,2-ethanediol), monopropylene glycol (MPG, also known as 1,2-propanediol), and 1,2-butanediol (BDO, also known as butylene glycol). These glycols may be present in a concentration of 0.1 to 40 wt. % based on the total weight of the liquid glycol composition. The liquid glycol composition may also include other by-products. The ethylene glycol reaction yield may be at least 60%.

[0080] The recovery of monoethylene glycol from the liquid glycol composition in step iv) may be carried out by a separation technique selected from adsorption, evaporation, distillation, extractive distillation, azeotropic distillation, vacuum distillation, atmospheric distillation, membrane separation, filtration, reactive purification or a combination thereof.

[0081] In one embodiment, monoethylene glycol is recovered by distillation. The distillation may be carried out in at least one distillation column. The distillation may be carried out at a temperature of 50 to 250°C, or 100 to 200°C. The distillation may be carried out at a pressure of at least 0.1 kPa, or at least 10 kPa, or at least 50 kPa. The pressure may be at most 400 kPa, or at most 200 kPa, or at most 120 kPa. It will be apparent to one skilled in the art to vary the temperature and pressure relative to each other to achieve the appropriate conditions.

[0082] The MEG recovered in step iv) may be subjected to an esterification reaction with terephthalic acid to form polyethylene terephthalate (PET). The esterification reaction may be carried out at a pressure of 0.27 to 0.55 MPa and a temperature of 220 to 260°C. Water formed during the reaction may be removed by distillation.

[0083] PET may be used to form a resin, which may be further processed into a container using, for example, injection molding or stretch blow molding.

[0084] The method disclosed herein has the additional advantage of utilizing wood chips having a specific size range. Wood chips of a specific size have the additional advantage of beneficially influencing the impregnation process. Wood chips of a specific size have the additional advantage of making the impregnation process more efficient, for example, the impregnation liquid may be evenly distributed on and absorbed into the wood chips, thereby requiring less impregnation liquid. Using wood chips of a specific chip size has the additional advantage of making the process easier to control. By limiting the amount of over-thick chips in the process, the formation of unhydrolyzed shives and rods in pretreatment i) may be reduced or minimized, and the yield of the fraction containing solid cellulose particles from pretreatment i) may be increased. This may then affect the yield of the carbohydrate fraction received from enzymatic hydrolysis ii) and the glycol yield received from catalytic conversion iii). The impregnation process described herein then has the additional advantage of beneficially influencing steam explosion so that a fraction containing solid cellulose particles with a larger surface area may be achieved. Therefore, the overall process for producing monoethylene glycol may be improved. [Example]

[0085] Reference will now be made in detail to embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings.

[0086] The following description discloses several embodiments in sufficient detail to enable one skilled in the art to utilize the arrangements and uses thereof and methods based on the present disclosure. Not all steps of the embodiments are discussed in detail, as many steps of the embodiments will be apparent to one skilled in the art based on the present disclosure.

[0087] For the sake of brevity, for repeated components, the item numbers are maintained in the following exemplary embodiment.

[0088] Attached Figures 1 and 2 show in some detail an example flow chart of a method for producing monoethylene glycol and the corresponding arrangement 1. The drawings are not drawn to scale and many of the components have been omitted for clarity. The arrangement 1 of Figure 2 for producing monoethylene glycol (MEG) from wood-based raw materials comprises at least one pre-treatment section 2 configured to subject a wood-based feedstock derived from the wood-based raw material to at least one pre-treatment to form a liquid fraction and a fraction comprising solid cellulose particles.

[0089] The arrangement of Figure 2 further includes a machine section 6 configured to subject the wood-based raw material to mechanical treatment. The mechanical treatment may be selected from debarking, chipping, splitting, cutting, beating, crushing, crushing, splitting, sieving, and / or washing the wood-based raw material to form a wood-based feedstock. The wood-based feedstock includes wood chips, and at most 5% by weight of the wood chips in the wood-based feedstock are over-thickness wood chips as defined by SCAN-CM 40:01.

[0090] One of the at least one pre-treatment section 2 is a pressurized reactor 2c configured to subject wood-based feedstock derived from wood-based raw materials to steam explosion.

[0091] The arrangement disclosed in Figure 2 further includes an impregnation reactor 2b operatively disposed prior to the pressurized reactor 2c. The impregnation reactor 2b is configured to subject the wood-based feedstock to at least one impregnation treatment with an impregnation liquid. The impregnation liquid may be selected from water, at least one acid, at least one alkali, at least one alcohol, or any combination or mixture thereof.

[0092] The arrangement disclosed in Figure 2 further includes a pre-steaming reactor 2a operatively disposed before the impregnation reactor 2b and the pressure reactor 2c. The pre-steaming section is configured to subject the wood-based feedstock to pre-steaming.

[0093] The at least one pretreatment section may include at least one of a presteaming reactor 2a, an impregnation reactor 2b, and a pressure reactor 2c, or may include two of these, or all three of these, in that order.

[0094] The pretreatment section is followed by at least one hydrolysis reactor 3. The at least one hydrolysis reactor 3 is configured to subject the fraction comprising the solid cellulose particles to enzymatic hydrolysis to form a lignin fraction and a carbohydrate fraction.

[0095] The arrangement disclosed in FIG. 2 further includes a conversion reactor 4 configured to subject the carbohydrate fraction to catalytic conversion to form a liquid composition of glycols.

[0096] The arrangement of Figure 2 further includes a distillation section 5 configured to recover monoethylene glycol from the liquid glycol composition.

[0097] Example 1 - Effect of wood chip size in wood-based feedstock In this example, the effect of the specific size of wood chips in a wood-based feedstock was examined. The wood-based feedstock was subjected to pre-steaming and subsequent impregnation as described herein. The impregnation was carried out using H2SO4 with an acid concentration of 13 g / L as the impregnation solution. The temperature of the impregnation solution was 90°C. The residence time was 1 minute. The results are shown in Table 1 below.

[0098] [Table 4]

[0099] From Table 1 above, it can be seen that the sulfur content measured as ICP mg / kg (Inductively Coupled Plasma Optical Emission Spectroscopy according to SFS-EN ISO 11885) increased as a result of the impregnation treatment indicating good impregnation with the impregnation solution.

[0100] It is obvious to those skilled in the art that with the advancement of technology, the basic idea may be implemented in various ways. Therefore, the embodiments are not limited to the above examples, instead, the embodiments may vary within the scope of the claims.

[0101] The embodiments described hereinabove may be used in any combination with each other. Some of the embodiments may be combined together to form further embodiments. The methods, arrangements, or monoethylene glycol disclosed herein may include at least one of the embodiments described hereinabove. It will be understood that the benefits and advantages described above may relate to one embodiment or to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or have any or all of the stated benefits and advantages. It will be further understood that reference to "an" item refers to one or more of those items. The term "comprising" is used herein to mean including the features or acts listed before the term "comprising" (after the term "comprising"), without excluding the presence of one or more additional features or acts.

Claims

1. 1. A method for producing monoethylene glycol (MEG) from wood-based raw materials, comprising: The wood-based raw material is selected from the group consisting of hardwood, softwood, and combinations thereof; i) providing a wood-based feedstock derived from the wood-based raw material and comprising wood chips, and subjecting the wood-based feedstock to at least one pretreatment to form a liquid fraction and a fraction comprising solid cellulose particles, wherein at most 3.5% by weight of the wood chips in the wood-based feedstock are over-thickness wood chips as defined by SCAN-CM 40:01, at most 3% by weight of the wood chips in the wood-based feedstock are fines as defined by SCAN-CM 40:01, and the remainder of the wood chips in the wood-based feedstock are wood chips whose chip size classification as defined by SCAN-CM 40:01 falls substantially between the over-thickness wood chips and the fines, and the over-thickness wood chips have a chip size classification as defined by SCAN-CM 40:

01. and wherein the fines are wood chips which pass through the first screen of a chip classifier but are retained on the second screen with 8 mm slots when chip size classification is performed as specified in SCAN-CM 40:01, and the fines are wood chips which are not retained on the fifth screen with 3 mm holes when chip size classification is performed as specified in SCAN-CM 40:01; and The pretreatment comprises subjecting the wood-based feedstock to at least one impregnation treatment with an impregnation liquid selected from a combination or mixture of water and at least one acid, the impregnation treatment being carried out in at least one impregnation reactor, the residence time of the wood-based feedstock in the impregnation reactor being 5 seconds to 5 minutes, and the temperature of the impregnation liquid being 20 to 99°C; ii) subjecting the fraction containing solid cellulose particles to enzymatic hydrolysis to form a lignin fraction and a carbohydrate fraction; iii) subjecting the carbohydrate fraction to catalytic conversion to form a liquid composition of glycols; iv) recovering monoethylene glycol from said liquid glycol composition; A method comprising:

2. The specific surface area (SSA) of the wood chips is 2 to 35 cm ２ / g, or 4 to 33 cm ２ / g, or 6 to 30 cm ２ / g, or 10 to 25 cm ２ / g, or 12 to 20 cm ２ The method of claim 1, wherein the hydroxyl group is 0.15 to 0.5g.

3. The geometric specific surface area (GSSA) of the wood chips is 4 to 40 cm ２ / g, or 5 to 35 cm ２ / g, or 6 to 30 cm ２ / g, or 10 to 25 cm ２ / g, or 12 to 20 cm ２ The method according to claim 1 or 2, wherein the saturation coefficient is 1 / g.

4. The method according to any one of claims 1 to 3, wherein the wood-based raw material is hardwood.

5. 5. The method of claim 4, wherein the hardwood is selected from the group consisting of beech, birch, ash, oak, maple, chestnut, willow, poplar, and any combination or mixture thereof.

6. 6. The method of any one of claims 1 to 5, wherein providing the wood-based feedstock comprises subjecting the wood-based raw material to a mechanical treatment selected from debarking, chipping, splitting, cutting, beating, crushing, shredding, splitting, sieving, and / or washing the wood-based raw material to form the wood-based feedstock.

7. 7. The method according to any one of claims 1 to 6, wherein the pretreatment in i) comprises subjecting the wood-based feedstock to steam explosion carried out by treating the wood-based feedstock with steam having a temperature of 130-240°C under a pressure of 0.17-3.25 MPaG, followed by sudden explosive decompression of the wood-based feedstock.

8. 8. The method of claim 7, wherein the pretreatment in i) comprises subjecting the wood-based feedstock to at least one impregnation treatment with an impregnation liquid selected from water, at least one acid, at least one alkali, at least one alcohol, or any combination or mixture thereof, before subjecting it to steam explosion.

9. 9. The method of claim 8, wherein the pretreatment in i) comprises subjecting the wood-based feedstock to a pre-steaming treatment before subjecting it to impregnation and / or steam explosion, and wherein the pre-steaming of the wood-based feedstock is carried out with steam having a temperature of 100-130°C at atmospheric pressure.

10. 10. The method according to any one of claims 1 to 9, wherein the enzymatic hydrolysis is carried out at a temperature of 30 to 70°C, or 35 to 65°C, or 40 to 60°C, or 45 to 55°C, or 48 to 53°C, while maintaining the pH of the fraction containing the solid cellulose particles at a pH value of 3.5 to 6.5, or 4.0 to 6.0, or 4.5 to 5.5, and the enzymatic hydrolysis is continued for 20 to 120 hours, or 30 to 90 hours, or 40 to 80 hours.

11. 11. The method of any one of claims 1 to 10, wherein the catalytic conversion of the carbohydrate fraction comprises subjecting the carbohydrate fraction to catalytic hydrogenation in the presence of water and a catalyst system.

12. 12. The method of any one of claims 1 to 11, wherein recovering monoethylene glycol from the liquid glycol composition is performed by distillation of the liquid glycol composition.

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