FIELD OF THE INVENTION

The invention relates to a method and an appa ^¬ ratus for producing a soluble carbohydrate containing fraction and a solid fraction. Further, the invention relates to a soluble carbohydrate containing fraction and its use. Further, the invention relates to a solid fraction and its use.

BACKGROUND OF THE INVENTION

Known from prior art is different methods for forming carbohydrates from different raw materials, such as biomass. Many bio-refinery processes, e.g. hy ^¬ drolysis, generate lignin and sugars after the treat ^¬ ment of the biomass.

OBJECTIVE OF THE INVENTION

The objective of the invention is to disclose a new method for producing a soluble carbohydrate con ^¬ taining fraction with high concentration. Another ob- jective of the invention is to produce a soluble carbo ^¬ hydrate containing fraction with increased concentra ^¬ tion and with improved recovery. Another objective of the invention is to improve fractionation of biomass for producing an improved, concentrated liquid fraction comprising soluble carbohydrates with high recovery and a soluble material free solid fraction.

SUMMARY OF THE INVENTION The method for increasing concentration of a soluble carbohydrate containing fraction according to the present invention is characterized by what is pre ^¬ sented in claim 1.

The apparatus for increasing concentration of a soluble carbohydrate containing fraction according to the present invention is characterized by what is pre ^¬ sented in claim 13.

The soluble carbohydrate containing fraction according to the present invention is characterized by what is presented in claim 17.

The solid fraction according to the present invention is characterized by what is presented in claim 19.

The use of the soluble carbohydrate containing fraction according to the present invention is characterized by what is presented in claim 23.

The use of the solid fraction according to the present invention is characterized by what is presented in claim 24.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and constitutes a part of this specification, illustrate some embodiments of the invention and together with the description help to explain the principles of the in ^¬ vention. In the drawings:

Fig. 1 is a flow chart illustration of a method according to one embodiment of the present inven ^¬ tion,

Fig. 2 is a flow chart illustration of a method according to another embodiment of the present in- vention, Fig. 3 is a flow chart illustration of a method according to another embodiment of the present in ^¬ vention,

Fig. 4 is a flow chart illustration of a meth- od according to another embodiment of the present in ^¬ vention

Fig. 5 is a flow chart illustration of a method according to another embodiment of the present in ^¬ vention,

Fig. 6 is a flow chart illustration of a method according to another embodiment of the present in ^¬ vention,

Fig. 7 is a flow chart illustration of a method according to another embodiment of the present in- vention,

Fig. 8 shows results from one example carried out according to one method embodiment of the present invention,

Fig. 9 shows results from one example carried out according to one method embodiment of the present invention, and

Fig. 10 shows results from one example carried out according to one method embodiment of the present invention .

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to a method for increas ^¬ ing concentration of a liquid fraction comprising solu- ble carbohydrates, such as a soluble carbohydrate con ^¬ taining fraction, in which lignocellulose material (3) formed by treating plant based raw material (1) is con ^¬ ducted into a separation stage (4,6) . In the method of the present invention, the method comprises at least one solid-liquid separation stage (4,6) for separating a soluble carbohydrate containing fraction (10) and/or a washing filtrate (12) from lignocellulose material (3) . The separation stage comprises one or more separa ^¬ tion steps. At least a part of the soluble carbohydrate containing fraction (10) and/or the washing filtrate (12) is recirculated to the lignocellulose material (3) , preferably before a desired separation step of the separation stage (4,6), for increasing concentration of the soluble carbohydrate containing fraction. Solids (11) and at least a part of the soluble carbohydrate containing fraction (10) are supplied out from the sep ^¬ aration stage. In one embodiment, at least a part of the washing filtrate (12) is supplied out from the sep ^¬ aration stage.

One embodiment of the method of the present in- vention is shown in Fig. 1. Another embodiment of the method of the present invention is shown in Fig. 2. Another embodiment of the method of the present invention is shown in Fig. 3. Another embodiment of the method of the present invention is shown in Fig. 4. Another embodi- ment of the method of the present invention is shown in Fig. 5. Another embodiment of the method of the present invention is shown in Fig. 6. Another embodiment of the method of the present invention is shown in Fig. 7.

The apparatus of the present invention comprises at least one solid-liquid separation device (4,6) into which lignocellulose material (3) formed by treating plant based raw material (1) is conducted and in which a soluble carbohydrate containing fraction (10) and/or a washing filtrate (12) are separated from lignocellu- lose material (3) . Further, the apparatus comprises at least one feeding device, such as a pump, for feeding the lignocellulose material (3) into the separation de ^¬ vice (4,6) . Further, the apparatus comprises at least one recirculation device for recirculating at least a part of the soluble carbohydrate containing fraction (10) and/or the washing filtrate (12) to the lignocellulose material (3) , preferably before a desired separation device or separation step, for increasing concentration of the soluble carbohydrate containing fraction. Fur ^¬ ther, the apparatus comprises means, such as discharge means or outlet means, for supplying solids (11) and at least a part of the soluble carbohydrate containing fraction (10) out from the apparatus. In one embodi ^¬ ment, the apparatus comprises means for supplying at least a part of the washing filtrate (12) out from the apparatus.

The invention is based on a solid-liquid separa ^¬ tion. Further, the invention is based on a recirculation of filtrates containing preferably sugars, such as a sol ^¬ uble carbohydrate containing fraction and/or washing fil- trate, in order to increase concentration of the soluble carbohydrate containing fraction. In the invention, sugar content of the soluble carbohydrate containing frac ^¬ tion can be increased by means of the recirculation of the filtrates in various applications. Simultaneously, the recovery of the liquid soluble carbohydrate contain ^¬ ing fraction can be increased and more pure solid frac ^¬ tion comprising solids can be formed. Further, carbohydrate content and purity of the solids can be increased by means of the present invention. Further, if the washing filtrate is formed so it can be utilized in the process. In one embodiment, small amount of washing is used and thus concentration of soluble compounds can be further increased. In one embodiment, a replacement washing is used which leads to further increase of the concentration of the soluble compounds and increase pu ^¬ rity of the solid fraction.

In this context, a washing filtrate means a dilute filtrate from a washing step in which the ligno- cellulose material is washed. In this context, a solu- ble carbohydrate containing fraction means a soluble carbohydrate containing filtrate, preferably with high concentration, which is separated from the lignocellu- lose material. In a preferred embodiment, the washing filtrate and soluble carbohydrate containing fraction include carbohydrates, preferably C5 sugars ( C ₅ Hi ₀ O ₅ or ( C ₅ ( H ₂ 0 ) _n ) - The soluble carbohydrate containing fraction may be comprise carbohydrates, such as monosaccharides ( C ₆ Hi ₂ 0 ₆ or C ₅ H ₁₀ O ₅ ) , disaccharides ( Ci ₂ H ₂₂ 0n ) , oligosaccha ^¬ rides and/or polysaccharides ( ( 0 ₆ Ηιο0 ₅ )η or ( 0 ₅ Η ₈ θ4)η) · Preferably, the soluble carbohydrate containing fraction comprises soluble C5 carbohydrates ( C ₅ Hi ₀ O ₅ or C ₅ ( H ₂ 0 ) _n ) and other carbohydrates. The washing filtrate and solu ^¬ ble carbohydrate containing fraction may comprise also other components. In a preferred embodiment, the solids comprise carbohydrates, and preferably solid C 6 carbohy- drates ( C ₆ Hi ₂ 0 ₆ or C ₆ ( H ₂ 0 ) _n ) - The solids may comprise also other carbohydrates and other components.

In this context, plant based raw material means any plant based raw material, e.g. wood based raw materi ^¬ al. The plant based raw material includes lignin, cellu- lose and hemicellulose . In one embodiment, the plant based raw material is selected from the group consisting of wood based raw material, wood, lignocellulose bio- mass, agricultural residues, bagasse based material, sugarcane bagasse, corn based material, corn stover, wheat straw, rice straw, woody biomass, woody perenni ^¬ als, vascular plants and the like and their mixtures and their combinations. In one embodiment, the plant based raw material is wood based raw material or a mix ^¬ ture comprising wood based material. In one embodiment, the plant based raw material comprises plant pieces, e.g. wood pieces.

In this context, lignocellulose material re ^¬ fers any lignocellulose material which has been formed by treating, such as pre-treating, from the plant based raw material by means of a suitable treatment method in one or more steps. In one embodiment, the lignocellu- lose material contains carbohydrates and lignin. Pref ^¬ erably, the carbohydrates have C _n ( H ₂ 0) n or C _n (H ₂ 0) _n -i · The carbohydrates can comprise monosaccharides (C ₆ Hi ₂ 0 ₆ or C ₅ H ₁₀ O ₅ ) , disaccharides (Ci ₂ H ₂₂ 0n) , oligosaccharides and/or polysaccharides ((0 ₆ Ηιο0 ₅ ) η or (0 ₅ Η ₈ θ4) η ) · Prefera ^¬ bly, the lignocellulose material includes carbohy ^¬ drates, such as soluble C5 carbohydrates (C ₅ Hi ₀ O ₅ or C ₅ (H ₂ 0) _n ) and solid C6 carbohydrates (C ₆ Hi ₂ 0 ₆ or C ₆ (H ₂ 0) _n )- The lignocellulose material may contain one or more lignocellulose material components. Preferably, the lignocellulose material is in the form of suspension which contains liquid, such as water. The lignocellu ^¬ lose material (3) is formed from the plant based raw material (1) and is treated in one or more treatment step (2,5) . In one embodiment, the lignocellulose mate ^¬ rial is formed or treated by treatment, preferably by pretreatment , selected from the group consisting of physical treatment, such as milling, extrusion, micro ^¬ wave treatment, ultrasound treatment and freeze treat- ment, chemical treatment, such as acid treatment, alka ^¬ line treatment, ionic liquid treatment, organosolv treatment and ozonolysis, physico-chemical treatment, such as steam explosion treatment, ammonia fiber explo ^¬ sion treatment, C0 ₂ explosion treatment, liquid hot wa- ter treatment and wet oxidation, biological treatment and their combinations. Preferably, the plant based raw material is treated to dissolve hemicellulose . In one embodiment, the lignocellulose material is formed or treated by the hydrolysis, e.g. acid hydrolysis, auto- hydrolysis, thermal hydrolysis, enzymatic hydrolysis, supercritical hydrolysis and/or subcritical hydrolysis, in which at least a part of lignin is separated from the raw material in connection with the hydrolysis. In one embodiment, the lignocellulose is formed or treated by the steam explosion, in which hemicelluloses are treated and in which at least a part of polysaccharides of the hemicelluloses degrade into monosaccharides and oligosaccharides. In one embodiment, the lignocellulose material is formed or treated by the hydrolysis and by the steam explosion in one or more steps. In one embod- iment, the lignocellulose material is formed or treated by the catalytic pretreatment , e.g. by using acid or base as catalyst. In the pretreatment process the plant based raw material enters the reactor unit where the pretreatment takes place. The lignocellulose material can be treated by means of one or more treatment. The treated lignocellulose material can be then blown to a blowtank. Further, the lignocellulose material can be preferably dewatered, e.g. by dewatering presses in two stages. The dewatering makes possible to separate sugar based streams. In one embodiment, the lignocellulose material consists of fine solid particles. By means of the fine particle size high yields and low amount of degradation may be achieved in the process. Preferably, fine solid particles are fiber-like or indefinable par- tides smaller than 0.2 mm, or they are particles that are small enough to pass through the Bauer McNett 200- mesh screen. Particle size of the lignocellulose mate ^¬ rial can be measured, e.g. with an optical measurement device, such as Metso FS5, or a laser diffraction meth- od, such as Coulter LS230. The values for particle size are depending on the method and thus values from Metso FS5 and Coulter LS230 cannot be directly compared. Par ^¬ ticle size of the solid particles can be defined based on ISO 16065-N or TAPPI T271. The pretreatment process decreases the particle size and fibre length of origi ^¬ nal wood fibre, which can be defined by separating fi ^¬ bres by cooking the wood in e.g. sulphate process or maceration. The sulphate process is resulting fibre length of about 80 % of the one after the maceration.

In one embodiment, dry matter content of the lignocellulose material is 20 - 80 % by weight after the pretreatment . The dry matter content is determined at 45 °C by means of evaporating. When the determina ^¬ tion of the dry matter content is made at temperature 45°C so also small-molecular organic compounds remain in the mass during the drying of the determination. In one embodiment, the determination of the dry matter content may be done so that it is based, at least part ^¬ ly or as applied, on NREL (National renewable energy laboratory) Laboratory Analytical Procedures for stand- ard biomass analysis determined in the Technical Report NREL/TR-510-48087 (revised July 2011) . In one embodi ^¬ ment, the lignocellulose material is diluted with liq ^¬ uid, preferably with water, or steam to form the ligno ^¬ cellulose material feed to the separation stage. In one embodiment, feed concentration of the lignocellulose material is 2 - 60 % by weight, preferably 5 - 30 % by weight, more preferable 10 - 20 % by weight, into a solid-liquid separation stage. If feed concentration of the lignocellulose material is low so then size of the device increases. Preferably, the washing filtrate and/or soluble carbohydrate containing fraction which is recirculated to the lignocellulose material is used in a dilution of the lignocellulose material.

In one embodiment, the lignocellulose material is fed by means of a pump, e.g. a mono pump or piston pump or other suitable pump, into the solid-liquid sep ^¬ aration stage. Selection of the pump is based on e.g. feed concentration and/or viscosity of the lignocellu ^¬ lose material.

The solid-liquid separation stage may comprise one or more separation steps. In one embodiment, the solid-liquid separation is carried out in one or more separation steps in the separation stage. In one embodiment, the solid-liquid separation stage comprises more than one sequential separation steps. In one embodi ^¬ ment, the solid-liquid separation stage comprises dif- ferent procedures which may be done in separate separa ^¬ tion steps. Alternatively, more than one procedure is done in one process step.

In one embodiment, the separation of the solu- ble carbohydrate containing fraction and the washing filtrate is carried out in the same separation step. In one embodiment, the separation of the soluble carbohy ^¬ drate containing fraction and the washing filtrate is carried out in the separate separation steps. In one embodiment, the soluble carbohydrate containing frac ^¬ tion is separated in one step. In one embodiment, the soluble carbohydrate containing fraction may be sepa ^¬ rated at the first step in two-step process or multi- step process. In one embodiment, the soluble carbohy- drate containing fraction may be separated at the last step in two-step process or multi-step process. In one embodiment, the soluble carbohydrate containing frac ^¬ tion may be separated between the first and the last steps. Alternatively, the soluble carbohydrate contain- ing fraction may be separated in more than one step. In one embodiment, a part of the soluble carbohydrates or a part of the soluble carbohydrate containing fraction may be separated in connection with the pretreatment process in which the lignocellulose material is formed and/or treated. In one embodiment, the washing fil ^¬ trate is separated in one step. In one embodiment, the washing filtrate is separated in more than one step. In one embodiment, the soluble carbohydrate containing fraction and/or washing filtrate is separated in each separation step.

In one embodiment, a washing filtrate is not separated from lignocellulose material (3) . Then, only a soluble carbohydrate containing fraction (10) is sep ^¬ arated from lignocellulose material (3) . In one embodi- ment, a washing step is not carried out, and the wash ^¬ ing filtrate is not formed. Then, only a soluble carbo- hydrate containing fraction (10) is separated from lig- nocellulose material (3) .

In one embodiment, the method comprises more than one separation stages. In one embodiment, the method comprises more than one sequential separation stages .

In one embodiment, the apparatus comprises more than one separation devices. In one embodiment, the solid-liquid separation stage comprises at least one separation device. In one embodiment, the solid- liquid separation stage comprises more than one separa ^¬ tion device. In one embodiment, one or more separation steps can be done in the same separation device. In one embodiment, the separation device comprises one or more separation step, e.g. separation segment.

In one embodiment, the separation device is based on a countercurrent washing. In one embodiment, the separation device is selected from the group con ^¬ sisting of filtration device, centrifugal device and their combinations. In one embodiment, the separation device is selected from the group consisting of pres ^¬ sure filtration device, vacuum filtration device, filtration device based on underpressure, filtration de ^¬ vice based on overpressure, filter press, other suita- ble press, centrifugal device and their combinations. In one embodiment, the separation device is a pressure filtration device, vacuum filtration device, filtration device based on underpressure or filtration device based on overpressure. Alternatively, the separation device can be another washing device in which low amount of washing water is used and washing is done in high dry matter content. Then good recovery can be achieved .

Preferably, the solid-liquid separation stage comprises the separation of the soluble carbohydrate containing fraction and/or the washing filtrate from lignocellulose material. In one embodiment, the soluble carbohydrate containing fraction and/or the washing filtrate are separated from lignocellulose material by means of filtration, centrifugal treatment or their combinations. In one embodiment, the filtration is car ^¬ ried out by pressure, underpressure or overpressure.

In one embodiment, the solid-liquid separation stage comprises a filtration in which the soluble car ^¬ bohydrate containing fraction is separated in a liquid form and a solid cake is formed. Preferably, pressure is used in the filtration. In one embodiment, liquid is separated by a pressure difference, such as by means of vacuum or overpressure. In one embodiment, the solid- liquid separation stage comprises a washing in which a displacement washing of the lignocellulose material is carried out with small amount clean water in order to remove majority of sugars, inhibitors and other soluble compounds from the solid lignocellulose material and to provide high recovery of soluble compounds. Preferably, ratio of washing water to solid is below 6, preferably below 3 and more preferably below 1.5. In one embodi ^¬ ment, the solid-liquid separation stage comprises the filtration and washing. In one embodiment, the filtra ^¬ tion and washing is carried out in a static chamber, preferably in a non-moving chamber. In one embodiment, the filtration and washing is carried out in one device under pressure without mixing between the filtration and washing. Preferably, said separation device com ^¬ prising the filtration and washing is in the vertical or horizontal plane, not in the inclined plane. High concentration and recovery of soluble material in the liquid phase can be achieved with small amount of clean water, and a solid fraction without soluble compounds can be achieved.

In one embodiment, the separation stage com ^¬ prises the extraction, liquid separation and washing. In one embodiment, the soluble carbohydrate containing fraction and/or the washing filtrate are separated from lignocellulose material by means of pressure filtration. In one embodiment, the apparatus comprises at least one pressure filtration device as the solid-liquid separation device. In one embodiment, the solid-liquid separation stage comprises one pres ^¬ sure filtration device. In one embodiment, the solid- liquid separation stage comprises more than one pres- sure filtration device. In a preferred embodiment, the washing in the pressure filtration device is based on a displacement of liquid. In one embodiment, the pressure filtration comprises a pumping step, pressing, washing step, pressing and removal of a cake. In the pumping step, the solid cake is formed and pressed. Preferably, in the pumping step, a chamber of the pressure filtra ^¬ tion device is filled, and pre-pressing is made. In one embodiment, air blow is made after the pumping step or after the first pressing step to further remove liquid from the cake. Preferably, the soluble carbohydrate containing fraction is separated in connection with the pumping step. In the washing step, washing water is pressed through the cake and the cake is pressed and preferably dewatered. In the washing step, the liquid of the cake can be displaced by water. In one embodi ^¬ ment, air blow is made in the washing step to further remove liquid from the cake. The washing filtrate is separated by pressing in connection with the washing step. The dewatered solid cake is removed from the pressure filtrate device. Preferably, the dewatered solid cake forms a solid fraction. An advantage of the pressure filtration is that all separation steps can be carried out by one device.

In different separation stages the separation can be carried out by means of similar or different separation methods or separation devices. In one embodiment, an amount of the washing filtrate is optimized by adjusting washing water ratio. In one embodiment, the ratio of the washing water to solid composition is 1:1 - 6:1, preferably, 1:1 - 5:1, more preferable 1:1 - 4:1, most preferable 1:1 - 3:1, in the washing. Preferably, the water balance is opti ^¬ mized in the method of the present invention.

In one embodiment, at least a part of the washing filtrate and/or soluble carbohydrate containing fraction is recirculated to the lignocellulose material before the separation stage. In one embodiment, at least a part of the washing filtrate and/or soluble carbohydrate containing fraction is recirculated to the lignocellulose material before the desired separation step of the separation stage, e.g. before the first separation step or between two separation steps. In one embodiment, at least a part of the washing filtrate and/or soluble carbohydrate containing fraction is re ^¬ circulated back to the lignocellulose material which is fed in the same separation stage. In one embodiment, at least a part of the washing filtrate and/or soluble carbohydrate containing fraction is recirculated to the lignocellulose material which is fed to the next sepa ^¬ ration stage or next separation step of the separation stage. In one embodiment, at least a part of the wash ^¬ ing filtrate and/or soluble carbohydrate containing fraction is recirculated by supplying into a blow tank, into entry side of solid-liquid separation device, into entry side of feeding device or into first step of the solid-liquid separation device, e.g. into first step of the pressure filtration device. In one embodiment, at least a part of the washing filtrate and/or soluble carbohydrate containing fraction is recirculated back to a desired separation step, e.g. segment, of the sep- aration device. In one embodiment, at least a part of the washing filtrate and/or soluble carbohydrate con- taining fraction is recirculated back to a previous separation step, e.g. segment, of the separation de ^¬ vice. In one embodiment, at least a part of the washing filtrate and/or soluble carbohydrate containing frac- tion is recirculated back to a previous separation step, e.g. segment, from each separation step in the separation device. In one embodiment, at least a part of the washing filtrate and/or soluble carbohydrate containing fraction is recirculated continuously. In one embodiment, at least a part of the washing filtrate and/or soluble carbohydrate containing fraction is re ^¬ circulated in each separation step of the separation stage or in each separation stage. An amount of washing water can be decreased by means of the recirculation.

In one embodiment, the washing filtrate is re ^¬ circulated, preferably totally, to the lignocellulose material. In one embodiment, 80 - 100 w-% of the wash ^¬ ing filtrate is recirculated to the lignocellulose ma ^¬ terial. In one embodiment, the washing filtrate con- tains washing water and carbohydrates, such as galac ^¬ tose, glucose, mannose, arabinose, xylose, glucuronic acid and galacturonic acid. Further, the washing fil ^¬ trate may contain soluble lignin.

In one embodiment, at least a part of the sol- uble carbohydrate containing fraction is recirculated to lignocellulose material. In one embodiment below 80 w-%, in one embodiment below 50 w-%, in one embodiment below 30 w-%, and in one embodiment below 20 w-%, of the soluble carbohydrate containing fraction of all liquid with soluble carbohydrates and other compounds is recirculated to the lignocellulose material.

In one embodiment, recirculation rate of the soluble carbohydrate containing fraction without the washing filtrate can be 0 - 95 %, more preferably 60 - 90 %, in one step process. When the washing filtrate is also used as dilution water recirculation rate of the soluble carbohydrate containing fraction can be 0 - 90 %, more preferably 35 - 80 %, in one step process.

In one embodiment, at least a part of the sol ^¬ uble carbohydrate containing fraction is recirculated to lignocellulose material. In one embodiment, the washing filtrate is recirculated to lignocellulose ma ^¬ terial. In one embodiment, a mixture of the washing filtrate and soluble carbohydrate containing fraction is recirculated to the lignocellulose material. In one embodiment, the washing filtrate and soluble carbohy ^¬ drate containing fraction is mixed to form a mixture, and the mixture is recirculated to the lignocellulose material .

Preferably, the feed concentration of the lig- nocellulose material is optimized by recirculation com ^¬ position.

In one embodiment, the sugar concentrate of the soluble carbohydrate containing fraction is opti ^¬ mized. Preferably, the soluble carbohydrate containing fraction contains soluble C5 carbohydrates. Total car ^¬ bohydrate content can be measured with HPLC after acid hydrolysis according to standard SCAN-CM 71:09. Mono- meric carbohydrate content can be measured with HPLC from liquid fraction directly without acid hydrolysis. The soluble carbohydrate containing fraction may con ^¬ tain also C6 carbohydrates, preferably below 20 w-%. Preferably, the soluble carbohydrate containing frac ^¬ tion can contain other monosaccharides, disaccharides , oligosaccharides and/or polysaccharides. In one embodi- ment, the soluble carbohydrate containing fraction con ^¬ tains galactose, glucose, mannose, arabinose, xylose, glucuronic acid and galacturonic acid. In one embodi ^¬ ment, the soluble carbohydrate containing fraction com ^¬ prises soluble C5 carbohydrates, such as C ₅ Hi ₀ O ₅ or C5(H ₂ 0) _n , and other carbohydrates and some other com ^¬ pounds. In one embodiment, the soluble carbohydrate concentrate of the soluble carbohydrate containing fraction is over 50 g/1, preferably over 70 g/1, more preferable over 100 g/1 after the solid-liquid separa ^¬ tion. In one embodiment, the soluble carbohydrate con- centrate of the soluble carbohydrate containing frac ^¬ tion is below 250 g/1, in one embodiment below 200 g/1, in one embodiment below 150 g/1 after the solid-liquid separation. In one embodiment, the soluble carbohydrate concentrate of the soluble carbohydrate containing fraction is between 15 to 280 g/1, preferably 30 to 200 g/1, more preferable 50 to 165 g/1 after the solid- liquid separation. Preferably, the soluble carbohydrate containing fraction is in the form of solution. In one embodiment, water soluble matter is between 20 to 425 g/1, preferably 45 to 303 g/1, more preferable 75 to 250 g/1 after the solid-liquid separation. Water solu ^¬ ble matter can be determined by means of a method de ^¬ scribed later as "gravimetric washing method".

Preferably, at least a part of the soluble carbohydrate containing fraction is supplied out from the separation stage. The soluble carbohydrate contain ^¬ ing fraction can be supplied out after any desired step of the separation stage. In one embodiment, the soluble carbohydrate containing fraction is supplied out after the first step of the separation stage.

In one embodiment a soluble carbohydrate con ^¬ taining fraction (10) with high concentration can be formed. The soluble carbohydrate containing fraction is formed from lignocellulose material (3) which has been formed by treating plant based raw material (1), where ^¬ in the soluble carbohydrate containing fraction has been formed by separating the soluble carbohydrate con ^¬ taining fraction (10) and/or a washing filtrate (12) from solid lignocellulose material (3) in one or more separation stage (4,6) and by recirculating at least a part of the soluble carbohydrate containing fraction and/or washing filtrate to the lignocellulose material for increasing concentration of the soluble carbohydrate containing fraction. The soluble carbohydrate containing fraction may be used as component in manu- facturing a final product.

In one embodiment, a part of the soluble car ^¬ bohydrate containing fraction (14) is separated from the lignocelluloses material (3) in connection with the pretreatment step (2,5) in which the lignocellulose ma- terial is formed and/or treated. The soluble carbohy ^¬ drate containing fraction (14) may be separated by means of a similar separation method or device as used in the separation stage (4,6) or by means of other suitable separation method or device.

In one embodiment, two soluble carbohydrate containing fractions (10,14) with high concentration can be formed with high soluble compound recovery. Two soluble carbohydrate containing fractions are formed from lignocellulose material (3) which is formed by treating plant based raw material (1) in two or more steps. The first soluble carbohydrate containing frac ^¬ tion (14) is formed by separating a part of soluble compounds between the first and the last pretreatment steps (2,5) and the second soluble carbohydrate con- taining fraction (10) is formed by separating most of the soluble compounds after the last pretreatment step. Preferably, the second soluble carbohydrate containing fraction (10) is separated in the separation stage (4) so that the soluble carbohydrate containing fraction and/or a washing filtrate is separated from solid lig ^¬ nocellulose material and at least a part of the soluble carbohydrate containing fraction and/or washing filtrate is recirculated to the lignocellulose material for increasing concentration of the soluble carbohy- drate containing fraction. The soluble carbohydrate containing fractions (14) and (10) may be combined or used separately as component in manufacturing a final product. The combined or separate soluble carbohydrate containing fractions can be concentrated for further use .

In one embodiment, two soluble carbohydrate containing fractions (10,14) with high concentration can be formed with high soluble compound recovery. Two soluble carbohydrate containing fractions are formed from lignocellulose material (3) which is formed by treating plant based raw material (1) in two or more steps. The first soluble carbohydrate containing frac ^¬ tion (14) is formed so that liquid-solid ratio (w/w) of the lignocellulose material is below 5:1, preferably below 4:1, more preferably below 3:1 and most prefera- bly below 2:1 before separating a part of soluble com ^¬ pounds between the first and the last pretreatment steps (2,5). The second soluble carbohydrate containing fraction (10) is formed by separating most of the solu ^¬ ble compounds after the last pretreatment step. Prefer- ably, the second soluble carbohydrate containing frac ^¬ tion (10) is separated in the separation stage (4) so that the soluble carbohydrate containing fraction and/or a washing filtrate is separated from solid lig ^¬ nocellulose material and at least a part of the soluble carbohydrate containing fraction and/or washing filtrate is recirculated to the lignocellulose material for increasing concentration of the soluble carbohydrate containing fraction. Fresh washing water amount is less than 4:1 ( liquid : solid (w/w)), preferably less than 3:1, more preferably less than 2:1, the most pref ^¬ erably close to 1:1. The efficiency of removing soluble carbohydrate containing fraction from solid need to be high and it need to be higher than 60%, preferably more than 70%, more preferably more than 80%, the most pref- erable more than 90%. The soluble carbohydrate contain ^¬ ing fractions (10 and (14) may be combined or used sep- arately as component in manufacturing a final product. The combined or separate soluble carbohydrate contain ^¬ ing fractions can be concentrated for further use.

In one embodiment, a soluble carbohydrate con- taining fraction (10) with high concentration can be formed with high soluble compound recovery. The soluble carbohydrate containing fraction is formed from ligno- cellulose material (3) which is formed by treating plant based raw material (1) in one or more steps. The soluble carbohydrate containing fraction is formed by separating most of the soluble compounds after the last pretreatment step (2,5) so that the soluble carbohy ^¬ drate containing fraction and/or a washing filtrate is separated from solid lignocellulose material and at least a part of the soluble carbohydrate containing fraction and/or washing filtrate is recirculated to the lignocellulose material for increasing concentration of the soluble carbohydrate containing fraction. The solu ^¬ ble carbohydrate containing fraction may be used as component in manufacturing a final product. The soluble carbohydrate containing fractions can be concentrated for further use.

In one embodiment, a soluble carbohydrate con ^¬ taining fraction (10) with high concentration can be formed with high soluble compound recovery. The soluble carbohydrate containing fraction is formed from ligno ^¬ cellulose material (3) which is formed by treating plant based raw material (1) in one or more steps. The soluble carbohydrate containing fraction is formed by separating most of the soluble compounds after the the last pretreatment step (2,5) so that the soluble carbo ^¬ hydrate containing fraction and/or a washing filtrate is separated from solid lignocellulose material and at least a part of the soluble carbohydrate containing fraction and/or washing filtrate is recirculated to the lignocellulose material for increasing concentration of the soluble carbohydrate containing fraction. Fresh washing water amount is less than 4:1 (liq ^¬ uid : solid (w/w) ) , preferably less than 3:1, more prefer ^¬ ably less than 2:1, the most preferably close to 1:1. The efficiency of removing soluble carbohydrate con ^¬ taining fraction from solid need to be high and it need to be higher than 70%, preferably more than 80 ~6 , more preferably more than 90%, the most preferable more than 95%. The soluble carbohydrate containing fraction may be used as component in manufacturing a final product. The soluble carbohydrate containing fractions can be concentrated for further use.

In one embodiment, the soluble carbohydrate containing fraction is recovered. In one embodiment, the soluble carbohydrate containing fraction is sup ^¬ plied to a further processing. In one embodiment, the monomerization of the soluble carbohydrate containing fraction is made before the further processing. In one embodiment, the soluble carbohydrate containing frac- tion is supplied to a fermentation process. In one em ^¬ bodiment, the soluble carbohydrate containing fraction is used as a source material in fermentation. In one em ^¬ bodiment, the soluble carbohydrate containing fraction is supplied to a hydrolysis process. In one embodiment, the soluble carbohydrate containing fraction is used as a source material in hydrolysis, such as by acid hydroly ^¬ sis, enzymatic hydrolysis or the like. In one embodiment, the soluble carbohydrate containing fraction is sup ^¬ plied to a catalytic treatment process. In one embodi- ment, the soluble carbohydrate containing fraction is used as a source material in the catalytic process. The soluble carbohydrate containing fraction may be sup ^¬ plied directly to a fermentation, hydrolysis, catalytic treatment process or other suitable process, or alter- natively via a suitable treatment step or an additional step, e.g. additional concentration step or purifica- tion step, to a fermentation, hydrolysis, catalytic treatment process or other suitable process.

In one embodiment, at least a part of the washing filtrate is supplied to another process or pro- cess step. In one embodiment, the washing filtrate is used as a dilution water in the other process, e.g. in the pretreatment process. In one embodiment, the washing filtrate is used as a washing water in the other process.

Solids (11) are supplied out from the solid- liquid separation stage (4,6) . In one embodiment, a solid fraction comprising solids is supplied out from the solid-liquid separation stage. In one embodiment, the solid fraction comprising solids (11) is formed from lignocellulose material (3) which has been formed by treating plant based raw material (1) so that the solid fraction has been formed by separating a soluble carbo ^¬ hydrate containing fraction (10) and/or a washing filtrate (12) from solid lignocellulose material by means of at least one solid-liquid separation stage (4,6) and by recirculating at least a part of the soluble carbo ^¬ hydrate containing fraction and/or the washing filtrate to the lignocellulose material (3), and the solids (11) has been recovered from the separation stage. In one embodiment, the solids comprises C6 carbohydrates, such as (C ₆ Hi ₂ 0 ₆ or (C ₆ (H ₂ 0) _n )/ other solid carbohydrates and lignin, and some other compounds, such as some residual soluble material. In one embodiment, the solid fraction is in the form of a cake. In one embodiment, dry matter content of the cake is 40 - 80 % by weight, preferably 45 - 70 % by weight, more preferably 50 - 60 % by weight, after the solid-liquid separation stage. In one embodiment, dry matter content of the cake is 7 - 70 % by weight, preferably 15 - 45 % by weight, more prefer ^¬ ably 25 - 35 % by weight, after the solid-liquid sepa- ration stage. In one embodiment, the solid fraction con ^¬ tains soluble compounds below 15 %, preferably below 6 %, more preferably below 3 % by weight, after the solid- liquid separation stage. In one embodiment, water soluble matter is determined by a gravimetric washing method. The determination by the gravimetric washing method may be done as following: dry matter content (DM%) of raw material, e.g. the solid and soluble fraction, is measured at 60 °C, the amount of solids remaining after heating the sample at 60 °C to constant weight is measured and dry matter content is calculated based on wet and dry weights. For washing about 10 g bone dry of the wet mate ^¬ rial under investigation is taken, weighted (exact weighed amount) and mixed with hot water (50°C) in a ves ^¬ sel so that total amount is 200 g, the mixture is mixed 20 s (Bamix Mono freehand food blender, ^X C blade, speed 1 (7000 rpm) ) , the mixture is soaked with soaking time 5 min, the mixture is mixed 10 s (Bamix Mono freehand food blender, C blade, speed 1 (7000 rpm) ) , mass of a dry filter paper is measured, the mixture is filtered by means of Buchner (dia.125 mm) and the filter paper, an inward relief valve is closed when a cake is matt (dry) in whole, a filtrate is taken and the blender and vessel is washed with the filtrate and the filtrate is filtered again through the cake, the cake is washed three times with hot water, a 100 g, so that suction effect is main- tained the whole time and washing water (100 g) is added when the cake is matt (dry) in whole, a foil dish is weighed, the cake with the filter paper is dried in the foil dish, the dried cake (60°C) with the filter paper is weighed in the foil dish and mass of the filter paper and foil dish is subtracted from mass of the dried cake, fil ^¬ ter paper and foil dish, and then soluble matter free solid, i.e. water insoluble solids (WIS) of wet material under investigation, can be determined. Water insoluble solids, WIS%, can be calculated: WIS% = (weight of washed and dried material, e.g. the cake)/ (weight of the wet slurry for washing, e.g. the raw material). Water soluble matter, WS%, of dry matter can be calculated: WS% = (dry matter (DM%) of the original slurry, e.g. the raw material) -(water insoluble solids, WIS%) . In one embodiment, with high soluble material content (25 - 50 % of total dry matter soluble) of raw material, the solid fraction contains soluble compounds below 15 %, preferably below 9 %, more preferably below 5 % by weight, after the solid- liquid separation stage, measured by gravimetric washing method. In one embodiment, with lower soluble material content (below 25 % of total dry matter soluble) of raw material, the solid fraction contains soluble compounds below 9 %, preferably below 6 %, more preferably below 3 % by weight, after the solid-liquid separation stage, measured by gravimetric washing method.

Particle size of the solid particles can be defined, e.g. by an optical measurement device, such as Metso FS5, or by a laser diffraction method, such as Coulter LS230. In one embodiment, particle size of the solid particles can be defined based on ISO 16065-N or TAPPI T271. Fibre length of the solid particles can be defined based on ISO 16065-N, when fibres are defined as material longer than 0.2 mm. Fibre length of the solid particles can be defined based on TAPPI T271, when fibre length is 0.01 to 7.60 mm. In connection with Metso FS5, Lc means contour length, i.e. center- line fiber length, which is fiber length measured from the fibers center line from one end to another. Length- weighted Lc(l) means length-weighted fiber length which is average fiber length measured from a fiber distribu- tion weighted according to the TAPPI T271 standards. Weight-weighted Lc (w) means weight-weighted fiber length which is likewise average fiber length measured from a fiber distribution weighted according to the TAPPI T271 standards. Arithmetic Lc (n) means arithmetic mean which is calculated from the population distribu ^¬ tion of fibers. In this result average length is calcu- lated from the length distribution. Fl(l)% means length weighted distribution % (width > 10 ym, length < 0.2 mm) . Fiber width is measured as integral value from the middle of the fiber to account for tapered ends.

In one embodiment, length-weighted particle length Lc(l) is below [(0.4) x (corresponding unrefined sulphate pulp fibre length)], preferably below [(0.3) x (corresponding unrefined sulphate pulp fibre length) ] , more preferable below [(0.2) x (corresponding unrefined sulphate pulp fibre length) ] , most preferable below [(0.1) x (corresponding unrefined sulphate pulp fibre length) ] .

In one embodiment, fine particle width (frac ^¬ tion 0 - 0.2 mm) is below [(0.7) x (corresponding unre- fined sulphate pulp fibre length) ] , preferably below [(0.6) x (corresponding unrefined sulphate pulp fibre length)], more preferable below [(0.5) x (corresponding unrefined sulphate pulp fibre length) ] , most preferable below [(0.4) x (corresponding unrefined sulphate pulp fi- bre length) ] .

In one embodiment, the solid fraction comprises fine solid particles which are fiber-like or indefinable particles with longest dimension shorter than 0.2 mm measured with optical Metso FS5 (fraction Fl (1) of length weighted Lc(l) measurements and calculations). In one em ^¬ bodiment, the solid fraction of hardwood comprises par ^¬ ticles with longest dimension shorter than 0.2 mm over 70 % (Fl (1) >70 %) , preferably over 80 %, more preferably over 90 % and most preferably ονθ- 98 "6 by weight, de- fined by Metso FS5. In one embodiment, the solid frac ^¬ tion of softwood comprises particles with longest dimen ^¬ sion shorter than 0.2 mm over 50 % (Fl (1) >50 %) , preferably over 60 %, more preferably over 70 % and most preferably over 80 % by weight, defined by Metso FS5.

In one embodiment, the solid fraction compris ^¬ es fine solid particles which are fiber-like or indefin- able particles. The length weighted length Lc(l) of solid fraction is measured based TAPPI T271 standard includes all the particles detected and filling the requirements of measurement. TAPPI T271 defines fiber length of ma- terial to have longest dimension from 0.01 to 7.60 mm.

In one embodiment, the solid fraction compris ^¬ es fine solid particles which are fiber-like or indefin ^¬ able particles. The length weighted length Lc(l) of solid fraction is measured with Metso FS5. The length weighted Lc(l) -value is 40 % or less of the length of correspond ^¬ ing unrefined sulphate pulp fibre length, preferably 30 % or less, more preferably 20 % or less, most preferably 10 % or less. And the width of the fine particle fraction of length weighted particles (Lc (1) fraction 0 - 0.2 mm) is 70 % or less of width of the corresponding sulphate pulp fibre, preferably 60 % or less, more preferably 50 % or less, the most preferably 40 % or less.

In one embodiment, the solid fraction of hard ^¬ wood comprises fine solid particles which are fiber- like or indefinable particles. The length weighted length Lc(l) of solid fraction is measured with Metso FS5. The length weighted Lc (1) fractions over 0.2 mm fibre length is 50 % or less, preferably 35 % or less, more preferably 20 % or less, most preferably 5 % or less.

In one embodiment, the solid fraction of soft ^¬ wood comprises fine solid particles which are fiber ^¬ like or indefinable particles. The length weighted length Lc(l) of solid fraction is measured with Metso FS5. The length weighted Lc (1) fractions over 0.2 mm fibre length is 60 % or less, preferably 45 % or less, more preferably 30 % or less, most preferably 15 % or less.

In one embodiment, a solid fraction comprising solids (11) is supplied out from the solid-liquid sepa ^¬ ration stage (4,6,) . In one embodiment, the solid frac- tion is supplied out after the latest solid-liquid sep ^¬ aration stage. In one embodiment, at least a part of the solid fraction is supplied out between two separa ^¬ tion stages or between two separation steps.

In one embodiment, the solid fraction is sup ^¬ plied to a hydrolysis which may be selected from the group consisting of acid hydrolysis, enzymatic hydroly ^¬ sis, supercritical hydrolysis and/or subcritical hy ^¬ drolysis and their combinations, or to a manufacture of a composite material or a combustion process or other suitable process or their combinations. The solid frac- tion may be supplied directly to a hydrolysis, manufac ^¬ ture of a composite material, combustion process or other suitable process, or alternatively via a suitable treatment step or an additional step, e.g. additional concentration step or purification step, to a hydroly- sis, manufacture of a composite material, combustion process or other suitable process.

The method according to the present invention provides the soluble carbohydrate containing fraction and solid fraction with high concentration and with good quality. The solid fraction has very high concen ^¬ tration of lignin and glucan and its hydrated products. Further, the solid fraction has very high purity. In the present invention water balance can be optimized. Then the soluble carbohydrate content can be increased in the soluble carbohydrate containing fraction. The present invention demonstrates improved sugar recovery. Further, the present invention minimizes waste water, and decreases post-treating costs of the soluble carbohy ^¬ drate containing fraction. High concentration is achieved with low energy consumption.

The present invention provides an industrially applicable, simple and affordable way of making the soluble carbohydrate containing fraction with high concentration. The method according to the present inven- tion is easy and simple to realize as a production pro ^¬ cess. The method according to the present invention is suitable for use in the manufacture of the different sugar based fractions and final products from different starting materials. EXAMPLES

The invention is described in more detail by the following examples with reference to accompanying drawings . Example 1

In this example a soluble carbohydrate con ^¬ taining fraction is produced according to a process of Fig.1.

The lignocellulose material (3) is formed from plant based raw material (1) by means of pre-treatment (2) . The lignocellulose material (3) is fed into a sol ^¬ id-liquid separation stage (4) comprising a pressure filtration device. A soluble carbohydrate containing fraction (10) containing C5 sugars is separated from the lignocellulose material in the pumping and pressing step of the pressure filtration. A washing filtrate (12) is separated from the lignocellulose material (3) in the washing step of the pressure filtration. The washing filtrate (12) and at least a part of the solu- ble carbohydrate containing fraction (10) are recircu ^¬ lated to the lignocellulose material before the pres ^¬ sure filtration device. A solid cake (11) containing e.g. solids, solid carbohydrates, lignin and some solu ^¬ ble sugar, oligomer and polymer residual is removed from the pressure filtration device.

Example 2

In this example a soluble carbohydrate con ^¬ taining fraction is produced according to a process of Fig.2. The lignocellulose material (3) is formed from plant based raw material (1) by means of pre-treatment (2) . The lignocellulose material (3) is fed into a sol ^¬ id-liquid separation stage (4) comprising a pressure filtration device. A soluble carbohydrate containing fraction (10) containing C5 sugars is separated from the lignocellulose material in the pumping and pressing step of the pressure filtration. A washing filtrate (12) is separated from the lignocellulose material (3) in the washing step of the pressure filtration. The washing filtrate (12) is recirculated to the lignocel ^¬ lulose material before the pressure filtration device. The soluble carbohydrate containing fraction (10) in ^¬ cluding C5 sugars is removed from the pressure filtra- tion device. A solid cake (11) containing e.g. solids, solid carbohydrates, lignin and some soluble sugar, ol ^¬ igomer and polymer residual is removed from the pres ^¬ sure filtration device. Example 3

In this example a soluble carbohydrate con ^¬ taining fraction is produced according to a process of Fig.3.

The lignocellulose material (3) is formed from plant based raw material (1) by means of pre-treatment (2) . The lignocellulose material (3) is fed into a sol ^¬ id-liquid separation stage (4) comprising a pressure filtration device. A soluble carbohydrate containing fraction (10) containing C5 sugars is separated from the lignocellulose material in the pumping and pressing step of the pressure filtration. A washing filtrate (12) is separated from the lignocellulose material in the washing step of the pressure filtration. The wash ^¬ ing filtrate (12) may be recirculated to the pre- treatment (2) of the lignocellulose material. Alterna ^¬ tively, the washing filtrate (12) is removed from the pressure filtration device and recirculated to other process. At least a part of the soluble carbohydrate containing fraction (10) is recirculated to the ligno ^¬ cellulose material before the pressure filtration de- vice. A solid cake (11) containing e.g. solids, solid carbohydrates, lignin and some soluble sugar, oligomer and polymer residual is removed from the pressure fil ^¬ tration device.

Example 4

In this example a soluble carbohydrate con ^¬ taining fraction is produced according to a process of Fig. 4.

The lignocellulose material (3) is formed from plant based raw material (1) by means of pre-treatment (2) . The lignocellulose material (3) is fed into a sol ^¬ id-liquid separation stage (4) comprising a filtration device. A soluble carbohydrate containing fraction (10) containing C5 sugars is separated from the lignocellu ^¬ lose material in the filtration. At least a part of the soluble carbohydrate containing fraction (10) is recir ^¬ culated to the lignocellulose material before the fil ^¬ tration device. A solid cake (11) containing e.g. sol ^¬ ids, solid carbohydrates, lignin and some soluble sug ^¬ ar, oligomer and polymer residual is removed from the filtration device.

Example 5

In this example a soluble carbohydrate con- taining fraction is produced according to a two-step process of Fig.5.

The lignocellulose material (3) is formed from plant based raw material (1) by means of pre-treatment (2), e.g. by milling. The lignocellulose material (3) is fed into the first solid-liquid separation stage (4) comprising a pressure filtration device. A soluble car bohydrate containing fraction (10) containing C5 sugars is separated from the lignocellulose material in the pumping and pressing step of the pressure filtration. A washing filtrate (12) is separated from the lignocellu- lose material (3) in the washing step of the pressure filtration. The washing filtrate (12) and at least a part of the soluble carbohydrate containing fraction (10) are recirculated to the lignocellulose material before the first pressure filtration device. A part of the soluble carbohydrate containing fraction (10) may be removed from the process before the second separa ^¬ tion step.

In the second step the lignocellulose material (3) is treated by means of treatment stage (5), e.g. by physical, chemical or physic-chemical treatment such as by microwave or ultrasound treatment, or by steam ex ^¬ plosion. The lignocellulose material is fed into the second solid-liquid separation stage (6) comprising a pressure filtration device. A soluble carbohydrate con- taining fraction (10) containing C5 sugars is separated from the lignocellulose material in the pumping and pressing step of the pressure filtration. A washing filtrate (12) is separated from the lignocellulose ma ^¬ terial in the washing step of the pressure filtration. The washing filtrate (12) and at least a part of the soluble carbohydrate containing fraction (10) are re ^¬ circulated to the lignocellulose material before the first and/or second pressure filtration device. At least a part of the soluble carbohydrate containing fraction (10) is removed from the process.

A solid cake (11) containing e.g. solids, sol ^¬ id carbohydrates, lignin and some soluble sugar, oligo ^¬ mer and polymer residual is removed from the pressure filtration device. Example 6

In this example a soluble carbohydrate con ^¬ taining fraction is produced according to a two-step process of Fig.6.

The lignocellulose material (3) is formed from plant based raw material (1) by means of pre-treatment

(2) , e.g. by milling. The lignocellulose material (3) is fed into the first solid-liquid separation stage (4) comprising a pressure filtration device. A soluble carbohydrate containing fraction (10) containing C5 sugars is separated from the lignocellulose material in the pumping and pressing step of the pressure filtration. A washing filtrate (12) is separated from the lignocellu ^¬ lose material (3) in the washing step of the pressure filtration. The washing filtrate (12) and at least a part of the soluble carbohydrate containing fraction (10) are recirculated to the lignocellulose material before the second separation device. A part of the sol ^¬ uble carbohydrate containing fraction (10) may be re- moved from the process before the second separation step .

In the second step the lignocellulose material

(3) is treated by means of treatment stage (5), e.g. by physical, chemical or physic-chemical treatment such as by microwave or ultrasound treatment, or by steam ex ^¬ plosion. The lignocellulose material is fed into the second solid-liquid separation stage (6) comprising a pressure filtration device. A soluble carbohydrate con ^¬ taining fraction (10) containing C5 sugars is separated from the lignocellulose material in the pumping and pressing step of the pressure filtration. A washing filtrate (12) is separated from the lignocellulose ma ^¬ terial in the washing step of the pressure filtration. The washing filtrate (12) and at least a part of the soluble carbohydrate containing fraction (10) are re ^¬ circulated to the lignocellulose material before the second pressure filtration device. At least a part of the soluble carbohydrate containing fraction (10) is removed from the process.

A solid cake (11) containing e.g. solids, sol- id carbohydrates, lignin and some soluble sugar, oligo ^¬ mer and polymer residual is removed from the pressure filtration device.

Example 7

In this example a soluble carbohydrate con ^¬ taining fraction is produced according to a process of Fig.7.

The lignocellulose material (3) is formed from plant based raw material (1) by means of the first pre- treatment (2), e.g. by hydrolysis. After the pre- treatment a part of the soluble carbohydrates (14) is separated (13) in connection with the first pre- treatment step (2) . The lignocellulose material (3) is fed into the second pre-treatment step (5) in which the lignocelluloses material is treated, e.g. by steam ex ^¬ plosion. After that the lignocellulose material (3) is fed into a solid-liquid separation stage (4) comprising a pressure filtration device. A soluble carbohydrate containing fraction (10) containing C5 sugars is sepa- rated from the lignocellulose material in the pumping and pressing step of the pressure filtration. A washing filtrate (12) is separated from the lignocellulose ma ^¬ terial (3) in the washing step of the pressure filtra ^¬ tion. The washing filtrate (12) and at least a part of the soluble carbohydrate containing fraction (10) are recirculated to the lignocellulose material before the pressure filtration device. A solid cake (11) contain ^¬ ing e.g. solids, solid carbohydrates, lignin and some soluble sugar, oligomer and polymer residual is removed from the pressure filtration device. At least a part of the soluble carbohydrate containing fractions (10,14) is removed from the process.

Example 8

In this example a soluble carbohydrate con ^¬ taining fraction is produced.

Birch wood chips were pretreated in one-step autohydrolysis and steam explosion process to dissolve hemicellulose . The formed pretreated lignocellulose ma- terial was mixed with hot water and stirred for few hours. Then solid-liquid separation was done with Ou- totec Larox FP 0.3 two way pressure filter as described in the table 1. Filtration area was 0.27 m ² . To simulate the increase of concentration the soluble carbohydrate containing filtrate (10) of first pressing was used as a dilution water of next round, and again after second filtration the soluble carbohydrate containing filtrate of pressing was used in dilution of third filtration. Finally 5 filtration rounds were done. Filtration con- ditions are shown in Table 1.

Table 1

Washing with filter press

Target dry matter content of pre ^¬ o

O 12 treated lignocellulose material for

filter press

Dry matter content of pretreated raw o

0 65 material

Temperature of pretreated lignocel ^¬ °C 45-60 lulose material for filter press

Feeding and first press

Feeding time min 3-6

Pressure in feeding bar 3-5

Pressing pressure bar 5-6

Pressing time min 2 Washing conditions

Wash water temperature °C 40-60

Pressing pressure bar 10

Pressing time min 2

Air blowing

Blowing time min 1

Air flow 1/min 150-250

Total carbohydrate content was measured based on SCAN-CM 71 standard: acid hydrolysis and HPLC was used. As seen in figure 8, the carbohydrate content is increasing very well in line with simulated concentra ^¬ tion curve.

Simulation of the example was done with as ^¬ sumption of 15.7 % dissolving carbohydrate content of the pretreated lignocellulose material, which was also measured value of the lignocellulose material in exam ^¬ ple 8. As seen in figure 9, the concentration of the soluble carbohydrate containing filtrate coming out of the process will reach level of 104 g/1 in continuous process .

Example 9

In this example a soluble carbohydrate con ^¬ taining fraction is produced.

Birch wood chips were pretreated in one-step autohydrolysis and steam explosion process to dissolve hemicellulose . The formed lignocellulose material was mixed with hot water and stirred for few hours. Then solid-liquid separation was done with Outotec Larox FP 0.3 two way pressure filter as described in the table 1. Filtration area was 0.27 m ² . Amount of washing water was 2:1 (water:water insoluble solids).

To simulate the increase of concentration when all the washing filtrate (12) of the process and some soluble carbohydrate containing filtrate (10) of first pressing was calculated to use as dilution water of next round, and again after second filtration the washing filtrate and some soluble carbohydrate containing filtrate of pressing was used in dilution of third fil- tration. In this case about 77 % of dilution liquid was soluble carbohydrate containing filtrate. Recirculated soluble carbohydrate containing fraction was 70 % of all liquid with soluble compounds. Washing efficiency was assumed to be 90 %. Finally more than 70 iteration rounds were done. Simulation of the example was done with assumption of 15.7 % dissolving carbohydrate content of the pretreated lignocellulose material, which was also measured value of the lignocellulose material in example 8. As seen in figure 10, the concentration of soluble carbohydrate containing filtrate coming out of the process will reach level of 102 g/1 in continu ^¬ ous process.

Example 10

In this example a liquid and solid fraction is produced .

Birch wood chips were pretreated in two-step dilute acid steam explosion process to dissolve hemi- cellulose and to create soluble carbohydrate containing fraction. Portion of this soluble carbohydrate contain ^¬ ing fraction is removed before rapid pressure release of lignocellulose material in the steam explosion. The formed lignocellulose material was mixed with hot water and stirred for a while. Then solid-liquid separation was done with Outotec Larox PF 0.1 pressure filter as described in the Table 2. Filtration area was 0.1 m ² . Amount of washing water was 1:1 (water: dry matter in the cake) and 3:1. Results are shown in Table 3. Water soluble matter of dry matter is measured with gravimet- ric washing method. Table 2

Table 3

Pressure Lignocel ^¬ Only Pressing Pressing filtration lulose pressing + wash+ washwith PF 0.1 material ing 1 : 1 ing 3 : 1

Dry matter, 18.6

o

0

Water insol ^¬ 15.1 47.3 47.6 49.1 uble solids,

o

0

Water solu ^¬ 18.4 5.4 3.2 2.3 ble matter of dry mat ^¬ ter, %

Example 11

In this example a liquid and solid fraction is produced .

Birch wood chips were pretreated in two-step dilute acid steam explosion process to dissolve hemi- cellulose. The formed lignocellulose material was mixed with hot water and stirred for a while. Then solid- liquid separation was done with vacuum filtration fil- ter as described in the Table 4 (Vacuum filtration in laboratory) . Filtration area was 0.1 m ² . Amount of washing water varied from 0 to 8.6 (water: dry matter in the cake) .

Table 4

Vacuum filtration with Test Test Test Test Buchner 1 2 3 4

Dry matter content of o

0 19 19 19 19 pretreated lignocellu ^¬ lose material for vacuum

filter

Water insoluble solids o

0 15 15 15 15 of slurry

Temperature of slurry °C 50 60 60 60

Fed slurry ml 500 500 500 500

Vacuum mbar 0.6 0.6 0.6 0.6

Drying time s 60 10 10 10

Temperature of washing °C 60 60 60 water

Amount of washing water 1 250 500 750

Washing liquid/solid 0 2.7 5.7 8.6

Drying time min 0 60 60 60

Air flow 1/min 35 35 35 35 Cake wet thickness mm 24 26 28 26

Dry matter of cake o

0 32.9 31.4 30.4 30.8

Water soluble matter of o

0 18.4 9.2 5.9 3.2 dry matter

Example 12

In this example a concentrated liquid and pu- rified solid fraction is produced, based on example 10.

Birch wood chips were pretreated in two-step dilute acid steam explosion process to dissolve hemi- cellulose. The formed lignocellulose material was mixed with hot water and stirred for a while. Then solid- liquid separation was done with Outotec Larox PF 0.1 pressure filter as described in the Table 2. Filtration area was 0.1 m ² . Amount of washing water was 1:1 (wa ^¬ ter :water insoluble solids in the cake) and 3:1. Dry matter of original pretreated biomass was 65 %, dry matter in the first filtration was 16 %, and water insoluble solid content was 13 %. Water insoluble solid content was kept constant in filter press while dry matter of slurry was increased due to increased soluble material in slurry. Dry matter of washed cake was about 50 %. Composition of the solid fraction, which is further washed in laboratory like in gravimetric washing method to remove all water soluble material, is pre ^¬ sented in Table 5. The solid fraction was washed with water in order to remove residue soluble compounds, and after that the properties were determined.

To simulate the increase of concentration when all the washing filtrate (12) of the process and some soluble carbohydrate containing filtrate (10) of first pressing was calculated to use as dilution water of next round, and again after second filtration the washing filtrate and some soluble carbohydrate containing filtrate of pressing was used in dilution of third fil- tration. In 1:1 washing case about 83 % of dilution liquid was soluble carbohydrate containing filtrate and in 3:1 cssG 48 % of dilution liquid was soluble carbo ^¬ hydrate containing filtrate. Washing efficiency was calculated to be 83 % (1:1) and 88 % (3:1). Finally more than 70 iteration rounds were done. Simulation of the example was done with measured soluble matter con ^¬ tent of 18.4 % of the pretreated lignocellulose materi ^¬ al. The concentration of soluble matter containing fil- trate coming out of the process will reach level of 135 g/1 in continuous process with 1:1 washing and 99 g/1 with 3:1 washing.

Table 5

Property Uni Method Test Test t 1 2

Acid-insoluble lignin, T-222 33.4 34.0 gra .

Acid-soluble lignin, UV T-UM 250 1.5 1.5 205

Arabinose, acid hydroly ^¬ mg/ SCAN- 0.0 0.0 sis, HPAE-PAD g CM71

Rhamnose, acid hydroly ^¬ mg/ SCAN- 0.0 0.0 sis, HPAE-PAD g CM71

Galactose, acid hydroly ^¬ mg/ SCAN- 0.0 0.0 sis, HPAE-PAD g CM71

Glucose, acid hydroly ^¬ mg/ SCAN- 599.3 642.7 sis, HPAE-PAD g CM71

Xylose, acid hydroly ^¬ mg/ SCAN- 25.8 26.1 sis, HPAE-PAD g CM71

Mannose, acid hydroly ^¬ mg/ SCAN- 0.0 0.0 sis, HPAE-PAD g CM71

Carbohyrates , acid hy ^¬ mg/ SCAN- 625.1 668.7 drolysis , HPAE-PAD, total g CM71

FS5 Length weighted fi ^¬ mm Deter0.310 0.405 ber length Lc (1) ISO mined by Metso

FS5

based on

ISO

16065-N

or TAPPI

T271

FS5 Fiber width ym 23.8 19.1

FS5 Fines o

O 99.5 99.1

FS5 Fines (Flakes) o

O 95.0 93.5

FS5 Fines (Fibrils) o

0 0.0 0.0

Population based parti ^¬ mm 0.018 0.018 cle length Lc (n)

Length weighted particle mm 0.026 0.029 length Lc ( 1 )

Weight weighted particle mm 0.061 0.111 length Lc (w)

FS5 Fiber fractions 0- o

0 99.5 99.0

0.2 mm

FS5 Fiber fractions 0.2- o

0 0.4 0.8

0.6 mm

FS5 Fiber fractions 0.6- o

0 0.0 0.1

1.2 mm

FS5 Fiber fractions 1.2- o

0 0.0 0.0

2.0 mm

FS5 Fiber fractions 2.0- o

0 0.0 0.0

3.2 mm

FS5 Fiber fractions 3.2- o

0 0.0 0.0

7.6 mm

Particle width of frac ^¬ ym 4.3 4.4 tion 0-0.2 mm

Particle width of frac ^¬ ym 25.0 19.0 tion 0.2-0.6 mm

Particle width of frac ^¬ ym 11.7 15.5 tion 0.6-1.2 mm

Particle width of frac- ym 13.0 46.4 tion 1.2-2.0 mm

Particle with of frac ^¬ ym

tion 2.0-3.2 mm

Particle width of frac ^¬ ym

tion 3.2-7.6 mm

FS5 Mass fractions 0-0.2 o

0 88.7 87.0 mm

FS5 Mass fractions 0.2- o

0 11.2 11.1 0.6 mm

FS5 Mass fractions 0.6- o

0 0.2 0.8 1.2 mm

FS5 Mass fractions 1.2- o

0 0.0 1.2 2.0 mm

FS5 Mass fractions 2.0- o

0 0.0 0.0 3.2 mm

FS5 Mass fractions 3.2- o

0 0.0 0.0 7.6 mm

FS5 Number of pictures pes 639 644 (avg of 3)

FS5 Number of particles pes 11707 10662 (avg of 3) 6 1

Example 13

In this example a soluble carbohydrate frac ^¬ tion and solid fraction are produced.

Eucalyptus wood chips were pretreated in one- step autohydrolysis and steam explosion process with two different process conditions to dissolve hemicellu- lose. The formed pretreated lignocellulose materials were washed with hot water in laboratory to remove most of the water soluble compounds. These remaining, water soluble compound free solids were measured with two different particle size analyzer. The results of Metso FS5 and Coulter LS230 are presented in table 6 'two wa ^¬ ter insoluble solids of pretreated eucalyptus based lignocellulose materials' . Table 6

Unit Material Material 1 2

FS5 Length weighted fiber mm 0.332 0.462 length Lc (1) ISO

FS5 Fiber width ym 16.2 21.8

FS5 Fines o

0 98.6 86.8

FS5 Fines (Flakes) o

0 94.6 66.9

FS5 Fines (Fibrils) o

0 0.0 0.0

Population based particle mm 0.018 0.026 length Lc (n)

Length weighted particle length mm 0.031 0.099 Lc(l)

Weight weighted particle length mm 0.099 0.383 Lc (w)

FS5 Fiber fractions 0-0.2 mm o

0 98.6 86.8

FS5 Fiber fractions 0.2-0.6 mm o

0 1.3 9.6

FS5 Fiber fractions 0.6-1.2 mm o

0 0.1 3.6

FS5 Fiber fractions 1.2-2.0 mm o

0 0.0 0.0

FS5 Fiber fractions 2.0-3.2 mm o

0 0.0 0.0

FS5 Fiber fractions 3.2-7.6 mm o

0 0.0 0.0

Particle width of fraction 0- ym 5.9 7.9 0.2 mm

Particle width of fraction 0.2- ym 16.3 21.1 0.6 mm

Particle width of fraction 0.6- ym 15.4 23.6 1.2 mm

Particle width of fraction 1.2- ym

2.0 mm

Particle with of fraction 2.0- ym

3.2 mm

Particle width of fraction 3.2- ym

7.6 mm

FS5 Mass fractions 0-0.2 mm o

0 94.2 52.7 FS5 Mass fractions 0.2-0.6 mm o

O 5.7 32.3

FS5 Mass fractions 0.6-1.2 mm o

O 0.2 15.0

FS5 Mass fractions 1.2-2.0 mm o

0 0.0 0.0

FS5 Mass fractions 2.0-3.2 mm o

0 0.0 0.0

FS5 Mass fractions 3.2-7.6 mm o

0 0.0 0.0

Coulter LS Particle size Mean ym 36.5 54.8

Coulter LS Particle size Median ym 29.9 40.8

Coulter LS Particle size Mode ym 72.9 116.3

Coulter LS Particle size <50 ym o

0 70.6 57.0

Coulter LS Particle size <25 ym o

0 43.4 32.6

Coulter LS Particle size <10 ym o

0 19.2 11.6

Coulter LS Particle size <5 ym o

0 10.5 6.5

Coulter LS Particle size <2 ym o

0 4.3 2.8

Coulter LS Particle size <1 ym o

0 1.9 1.1

Coulter LS Particle size <0.5 o

0 0.8 0.3 ym

Coulter LS Particle size <0.3 o

0 0.4 0.1 ym

The method according to the present invention is suitable in different embodiments to be used for producing the most different kinds of sugar based_frac- tions from different raw materials.

The invention is not limited merely to the ex ^¬ ample referred to above; instead many variations are possible within the scope of the inventive idea defined by the claims.