Apparatus for rapid mixing of media and method

Abstract

The present invention relates to an apparatus, which can be part of a pre-treatment system in a plant for the production of fuels, e. g. bio-ethanol, derived from plant biomass, e. g. first generation crops, such as grain, sugarcane and corn or second generation crops such as lignocellulosic biomass. The invention relates to an apparatus for processing, such as fluffing and mixing, at least two media, such as a solid, e. g. biomass, and a fluid, e. g. steam, so as to rendering the first medium susceptible to efficient receiving of energy and/or mass which is provided by localized release of the second medium. Although the description of the present invention focuses on biomass, it is envisaged that the invention is generally applicable to control the mixing of at least two media by crossing their stream of while dispersing at least one of them.

Claims

1. An apparatus for processing at least two media by comminuting a first medium and mixing with a heated second medium, the apparatus comprising: i) a casing having at least one inlet for a first medium, wherein said first medium is a biomass in the form of pulp, ii) rotating means inside the casing, said rotating means generating mixing zones while being rotated, iii) at least one inlet for feeding a heated second medium to said mixing zones, iv) channels being located in said rotating means for dosing/injecting said heated second medium into said mixing zones v) at least one outlet for said first medium after being mixed with said heated second medium wherein said inlet for said first medium is adapted to advance the first medium towards the rotating means in a direction being parallel to or substantially parallel to a radius of the rotating means, and wherein said rotating means comprises protrusions adapted to comminute said first medium.

2. An apparatus as claimed in claim 1, wherein said apparatus further comprises a dewatering means upstream of and in fluid contact with at least one said inlet for a first medium.

3. An apparatus as claimed in claim 2, wherein said dewatering means is adapted to dewater and compact said first medium.

4. An apparatus as claimed in claims 2, wherein said dewatering means is a screw press.

5. An apparatus as claimed in claim 1, wherein said heated second medium is a heated gas.

6. An apparatus as claimed in claim 5, wherein said heated gas is steam.

7. An apparatus as claimed in claim 1, wherein said heated second medium is a chemical agent.

8. An apparatus as claimed in claim 7, wherein said chemical agent is sulfuric acid, sulfur dioxide, hydrochloric acid, nitric acid, phosphoric acid, maleic acid, oxalic acid, carbon dioxide, H3BW12O40, ozone, acetic acid, acetone, methanol, ethanol, phenols, ethylene glycol, tetrahydrofurfuryl alcohol, sodium hydroxide, calcium hydroxide, ammonia, water, methanesulfonic acid (MSA), nitrogen dioxide, or an oxidising agent.

9. An apparatus according to claim 1, wherein said channels are or comprise a number of channels at substantially mutually equidistant position.

10. An apparatus according to claim 1, wherein the rotating means comprises a series of alternating stacked circular spacers and circular discs, said alternating spacers and discs forming a substantially cylindrical body, wherein said discs comprise protrusions located on an outer edge, and wherein each subsequent disk (n+1) is rotated by a constant distance relative to a respective preceding disc (n), thereby off-setting the protrusions on each said subsequent disk (n+1) relative to each said preceding disc (n) such that the net arrangement of said protrusions is the formation of well-defined spiralling furrows (802) traversing the rotating means in a longitudinal direction.

11. An apparatus according to claim 1, wherein the rotating means is adapted to drive said first medium across said rotating means in a longitudinal direction from at least one said inlet for the first medium to at least one said outlet for said first medium.

12. An apparatus according to claim 1, wherein the biomass is contacted with one or more additional processing media in a first retention zone.

13. An apparatus according to claim 12, wherein the additional processing media is/are a heated gas and/or a chemical agent.

14. An apparatus according to claim 13, wherein the heated gas is steam, or the chemical agent is sulfuric acid, sulfur dioxide, hydrochloric acid, nitric acid, phosphoric acid, maleic acid, oxalic acid, carbon dioxide, H3BW12O40, ozone, acetic acid, acetone, methanol, ethanol, phenols, ethylene glycol, tetrahydrofurfuryl alcohol, sodium hydroxide, calcium hydroxide, ammonia, water, methanestilfonic acid (MSA), nitrogen dioxide, or an oxidising agent.

15. A system for producing bio-products from bio-mass material, the system comprising: i) a pre-processing subsystem for collecting, transporting, reducing to pulp, comminuting and delivering the material to a processing apparatus, ii) an apparatus according to claim 1, iii) a reactor chamber for changing chemical and/or physical structure, of said material.

16. A system according to claim 15, wherein the bio-products produced from the bio-mass material comprises bio-ethanol.

17. A method for processing at least two media, said method comprising: comminuting a first medium in a mixing zone of a processing apparatus and at the same time dosing/injecting a heated second medium into said mixing zone, said processing apparatus comprising: i) a casing having at least one inlet for receiving a first medium, wherein said first medium is a biomass in the form of pulp, ii) rotating means inside the casing, wherein said rotating means comprises protrusions in and generates said mixing zones while being rotated, iii) at least one inlet for feeding said heated second medium to said mixing zones, iv) channels being located in said rotating means for dosing/injecting said heated second medium into said mixing zones, and v) at least one outlet for said first medium after being mixed with said heated second medium, said method comprising advancing said first medium through said inlet towards said rotating means in a direction being parallel to or substantially parallel to a radius of the rotating means, so that said rotating means protrusions comminute said first medium, and injecting said heated second medium into said mixing zone to effect a rapid heat exchange between the heated second medium and a comminuted first medium.

18. A method as claimed in claim 17, wherein before the introduction into the processing apparatus the first medium is dewatered and compacted in a dewatering means such that said first medium enters the processing apparatus in the form of a compacted pulp.

19. A method as claimed in claim 18, wherein said first medium is dewatered and compacted by a screw feed.

20. A method as claimed in claim 18, wherein a dewatered first medium has a dry matter content of greater than 20%.

21. A method as claimed in claim 17, wherein said protrusions generate a turbulent flow in said mixing zones.

22. A method as claimed in claim 21, wherein said turbulent flow is in the form of a vortex.

23. A method as claimed in claim 17, wherein at least 75% of said comminuted first medium comprises particles having a diameter, or, in the case of a non-spherical particle, a largest dimension of less than 8 mm.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The apparatus according to the invention will now be described in more detail with regard to the accompanying figures. The figures show one way of implementing the present invention and is not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

(2) FIG. 1 shows a schematic representation of an axial cross sectional view of a device comprising the apparatus according to the invention including motor, gear and bearing located outside the apparatus.

(3) FIG. 2 shows a partial enlarged cross sectional view of the preferred embodiment of the apparatus according to the invention where 4 zones are identified on the basis of the dominating transport process, including a regular flow dominated zone, a turbulent flow dominated zone, a vortex dominated zone, a gravity dominated zone.

(4) FIG. 3 shows an axial cross sectional view of the preferred embodiment of the invention along the line I-I in FIG. 2.

(5) FIG. 4 shows a partial enlarged cross sectional view of the preferred embodiment along the line I-I in FIG. 2.

(6) FIGS. 5A-B show a schematic representation of a front view of a disc and a spacer element (FIG. 5A) and a prospective view (FIG. 5B) of the stacks of rotating disc and spacer elements in a specific embodiment of the invention.

(7) FIG. 6 shows a partial enlarged cross sectional view of a disc according to one of the embodiment of the invention.

(8) FIG. 7 shows a schematic representation of a cross sectional view of a preferred device comprising the apparatus according to the invention.

(9) FIG. 8A shows a schematic representation of a cross sectional view of a process initiator device II. FIG. 8B shows an alternative cross sectional view of the process initiator device II.

(10) FIG. 9A schematically shows the process of comminuting the biomass whilst simultaneously contacting said biomass with the second medium. FIG. 9B shows a preferred arrangement of the disks and spacers of the rotating means.

(11) FIG. 10 shows the correlation between particle size and heating time.

(12) FIG. 11 compares computer generated simulations of the apparatus of the invention (A, wheat straw, with forced convection; B, cubic wood chips with 0.4 cm dimensions, with forced convection) with simulations of a previously known analogous apparatus (C, cubic wood chips with 0.4 cm dimensions, no forced convection; D, cubic wood chips with 1 cm dimensions, no forced convection).

DETAILED DESCRIPTION OF AN EMBODIMENT

(13) Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms comprising or comprises do not exclude other possible elements or steps. Also, the mentioning of references such as a or an etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.

(14) FIG. 1 shows a schematic representation of an axial cross sectional view of a device 100 for processing two media, e. g. a solid, such as pulp and a liquid, such as water or a gas, such as steam. The device comprises a housing 101, such as a cylindrical vessel comprising the apparatus according to the invention, here referred as first reaction chamber 102 and a second reaction chamber 103. The two chambers are connected by means of a lid 104.

(15) The orientation of the device 100 is shown in FIG. 1 as perpendicular to action of gravity. In another embodiment the device can be oriented to be parallel to the action of gravity. In this latter case the influence of the action of gravity to the motion of the media is further enhanced.

(16) The device may be under pressure with the advantage of allowing the use of steam. However other gases or fluids may be used in the device under pressure. The device may also advantageously operate using super-heated steam. Super-heated steam is herein defined as steam at a temperature higher than its saturation temperature, i. e. boiling point. The saturation temperature is the temperature for a corresponding saturation pressure at which a liquid boils into its vapour phase. To increase the temperature of the steam higher than its saturated temperature at atmospheric pressure, the pressure in the device is raised to values higher than the atmospheric pressure. The steam is then described as super-heated by the number of temperature degrees through which it has been heated above saturation temperature.

(17) An external variable speed motor 108 including gear 106 and bearings 107 and rotating means 111 is also shown in FIG. 1.

(18) The first reaction chamber 102 comprises a casing 108, an inlet for the material to be processed 109, a series of rotating elements 110 and a lid 104. The first reaction chamber casing 108 has a conical shape with the apex towards the motor and the base towards the second chamber 103. The conical shape facilitates the flow of the processed materials, such as pulp, towards the second reaction chamber 103 by means of gravity. The base of the conical casing is the lid 104 of the first reaction chamber 102 which allows materials flow between the first and the second reaction chamber 103. The lid allows continuous feeding to the second reaction chamber 103 and provides a barrier to the backstream of reagents present into the second reaction chamber 103. The lid 104 therefore delimits the area of the first reaction chamber 102 and avoids mixture between the first reaction chamber environment and the emission from the following reaction processes which might occur in the second reaction chamber 103.

(19) The rotating elements 110, which are connected via a rotating means 111 to the variable speed motor 105 have the functions of i) providing comminution, dispersion and fluffing of the material introduced through inlet 109 and ii) exposing said material to a medium to allow rapid interaction, such as mixing/reacting, between the material and the medium. Such exposure can be carried at the time of the comminution, dispersion and fluffing or subsequently to the mechanical interaction between the material introduced and the rotating elements. The material during or after the mechanical interaction with the rotating elements may be exposed to one or more medium simultaneously or sequentially.

(20) The second reaction chamber allows 103 for further chemical or physical treatment of the material, such as pulp, for example oxidation induced by an oxidizing environment, e. g. by the presence of oxygen gas.

(21) The cross sectional view in FIG. 2 shows the apparatus according to the invention, i. e. the reaction chamber 102, corresponding to the first reaction chamber 102 of FIG. 1, comprising a casing 108, an inlet (not shown) for the material to be processed parallel o substantially parallel to a radius of the rotating means 111, a series of rotating elements 110 and a lid 104. The reaction chamber casing 108 has a conical shape with the apex directed towards the motor (not shown) and the base formed by the lid 104. The conical shape facilitates the flow of the materials, which in this embodiment will be referred as pulp, towards the lid 104 by means of gravity. The lid 104 allows flow of pulp out of the reactor chamber by mechanical opening 201.

(22) In the embodiment shown the rotating elements 110 are rotating discs fasten onto a rotating means, such as a drive shaft and being connected with a motor (not shown) located outside the casing 108.

(23) The rotating discs are designed in order to provide comminution, dispersion and fluffing of the pulp introduced and exposure of said material to a medium, i. e. gas or liquid, to produce a rapid interaction. The rotating discs are designed in order to optimize the medium release at the instant of comminution, dispersion and fluffing.

(24) The medium enters the reaction chamber 102 through inlet 202 and via conduit 203 is injected through outlet 204 into the reaction chamber.

(25) At the end 207 of the rotating means 111 functional elements may be added providing further functionality. In the embodiment shown, the elements 205 and 206 generate a vortex inducing mixture and transport of the pulp towards the lid 104. Alternatively a screw conveyer may be used and located at the end 207 of the rotating means.

(26) Close to the base of the reaction chamber 102 a temperature transmitter 208 is located allowing the control of the temperature of the pulp at the outlet 209. Optionally a gas outlet may be located along the side walls of the reaction chamber.

(27) In the reaction chamber 102 four zones can be identified based on the different dominating transport processes of the introduced material: a regular flow dominated zone 1, a turbulent flow dominated zone 2, a vortex dominated zone 3, a gravity dominated zone 4.

(28) In zone 1 the pulp is exposed to a mechanical treatment such as comminution, dispersion and fluffing provided by the rotating discs 110.

(29) In this zone 1 the transport of the pulp is induced by the mechanical treatment which the pulp is exposed to.

(30) Injection of the medium through the conduit 204 located in the rotating discs 110 is advantageous in this zone as injection is provided in a zone where intimate contact between freshly comminuted, dispersed and fluffed pulp and the medium is produced.

(31) In zone 2 the pulp comminuted, dispersed and fluffed at least partially, is further exposed to the contact with the medium released through the rotating discs 110 leading to further interaction between medium and pulp and the transport of the pulp mixed to the medium is dominated by turbulence flow regime. In zone 2 a different medium than the one previously introduced in zone 1 maybe further injected. This allows for sequential treatment of the pulp, for example the pulp may be treated with steam in zone 1 and with a chemical, such as oxygen peroxide, in the zone 2 leading to optimal oxidation.

(32) In this specific embodiment extra conduit located along the wall of the casing (not shown) are present to allow localized release of a medium.

(33) Sequential treatment of the pulp can be also obtained by release of different media between the initial part of the rotating discs 110 and the terminal part of the rotating discs 110. The initial part of the rotating discs 110 is defined as the part which is closer to the inlet for the material to be processed, while the terminal part is defined as the closer to the outlet 209 of the processed material.

(34) In the vortex dominated zone 3 the pulp introduced experiences a spinning, turbulent motion swirling rapidly around the axial direction of the rotating discs. The speed and rate of rotation are greatest at the centre, and decrease progressively with distance from the centre transporting the material towards the lid 104. In this zone the ratio between pulp and medium is in the order of 1:9.

(35) In the gravity dominated zone 4, the vortex influence into the motion of the pulp slowly decreases and the pulp moves by means of gravity towards the lid 104 and the reactor chamber opening 209. Here the head of the temperature probe 208 is in contact with the surface of the pulp which falls down onto it as the influence of the vortex motion decreases. The temperature probe 208 provides information about pulps temperature raise through the reaction chamber.

(36) FIG. 3 shows an axial cross sectional view of the preferred embodiment of the invention along the line I-I in FIG. 2. In FIG. 3 the connection between the rotating discs 110 and the drive shaft 111 is shown including a rotating structure 301, bearings 302 and a static support structure 303. The rotating discs 110 are connected together through bolts located in the bolt holes 304.

(37) The rotary velocity for the rotating disc may vary depending on the consistency, dry matter content, type, comminution, amount, particle size and distribution of the pulp and on the medium injected.

(38) The pulp is introduced through conduit 109 while the medium is introduced in the rotating discs through the axial inlet 305 and driven by the rotation of the discs 110 injected into the reaction chamber through tubular conduit 306 present into the disc structure.

(39) As a result of the rotor geometry the rotating discs, while rotating and therefore providing comminution, dispersion and fluffing of the pulp in small fibres, allow the injection of the medium into the pulp.

(40) Owing to the radial displacement effect, the comminution and the dispersion effect of the rotating discs an instantaneous inclusion of the injected medium in the pulp is achieved.

(41) In a preferred embodiment the medium is steam so that injection through the tubular conduits 306 in the rotating discs 110 and contact with the pulp lead to an almost instantaneous and effective heat transfer induced by the steam condensation. This allows an instantaneous temperature increase of the pulp avoiding denaturisation or burning. This fast temperature increase is mainly obtained combining the dispersion effect due to the rotating disc and the localized and immediate steam release through the tubular conduits present into the discs. In another embodiment the medium is a chemical reagent which is injected through the tubular conduits 306 while the pulp is comminuted, dispersed and fluffed by the rotating discs. This allows localized and immediate contact between the freshly dispersed and comminuted pulp and the chemical reagent causing a fast and efficient reaction between the two. Reaction time is therefore reduced since the chemical reagent is put in intimate contact with the pulp minimizing the diffusion time through the pulp.

(42) FIG. 4 shows in detail the structure of the rotating discs including the axial gas inlet 305, the tubular gas conduit 306 and the disc protrusions 401 of the rotating discs.

(43) Efficient mixing between the medium and the pulp may also be obtained thanks to turbulent flow. The discs protrusions 401 may be designed in order to provide turbulence to increase the reactivity between the pulp and the medium. A space, referred herein as a turbulence zone is formed between the periphery of the disc and the protrusions 401. This is where the most intense turbulence activity takes place. It should be understood, however that turbulence may occur, with less intensity in regions other than this space such as, e.g. in the regions 402 between the disc periphery and the sides walls of the reactor. Thus turbulence zone is used herein to refer to the region where the most intense turbulence takes place, and should not interpreted as turbulence cannot occur at some level in other regions of the reactor.

(44) FIGS. 5A-B show a schematic representation of a front view of a disc and a spacer element (FIG. 5A) and a prospective view (FIG. 5B) of the stacks of rotating disc and spacer elements in a specific embodiment of the invention.

(45) FIG. 5A shows a spacer 501 comprising a number of radially extending cut-outs 502. The cut-outs 502 of the spacer 501 initiating from the inner rim 503 towardsbut not to theouter rim 504. Similarly, the discs 505 comprising an equal number of radially extending cut-outs 506 initiating from a radial position 507 away from the inner rim 508 and to the outer rim 509 of the discs 505.

(46) In FIG. 5B spacers such as 501 and discs such as 505 are stacked alternating to a spacer a discs and so on. Furthermore, the spacers 501 and discs 505 are stacked so that the ends of the cut-outs 502 of the spacer 501 are located below the beginning of the cut-outs 506 of the discs 505. Thereby, channels are formed which extend from the inner rim 503 of the spacer 501 to the outer rim 509 of the discs 505. These channels are used to introduce one or more media in the sense disclosed above.

(47) In FIG. 5B aligning elements 510 are also shown.

(48) In some embodiments the number of bolts which link the stacked spacer and discs may be a prime number.

(49) FIG. 6 shows a partial enlarged cross sectional view of a disc according to one of the embodiment of the invention. Disc 601 comprises a number of radially extending cut-outs 602 initiating from a radial position 603 away from the inner rim 604 and to the outer rim 605 of the discs 601. When assembled for use discs such as 601 and spacer such as 501 in FIG. 5A are stacked alternating to a spacer a discs and so on similarly to FIG. 5B.

(50) Upon rotation of the stacked spacer/disc assembly, following arrow 606 the one or more media as disclosed above are introduced and through the channels shown in FIG. 4 reach the position 603. From 603 media are injected following arrow 607 into the apparatus while the pulp is comminuted, dispersed and fluffed by the rotating discs 601. This allows localized and immediate contact between the freshly comminuted pulp and the media causing a fast and efficient reaction between the pulp and media. In this embodiment the disc 601 is designed so as to provide a microjet effect from the radial position 603 to the outer rim 605.

(51) Furthermore the presence of a cutting edge 608 allows for a more efficient comminution of the pulp so that the pulp exposure to the media occurs on a freshly cut surface providing a fast and efficient intimate contact between the media and pulp. Reaction time is therefore reduced since the media is put in intimate contact with the pulp minimizing the diffusion time through the pulp.

(52) FIG. 7 shows a schematic representation of a cross sectional view of a preferred apparatus according to the invention. The apparatus preferably comprises three sections, labelled I, II and III (demarcated by dashed lines); IAn in-feed device IIA process initiator device IIIA second retention zone

(53) However, it should be understood that the process initiator device II may be used independently or in combination with either of the in-feed device I and/or the second retention zone III.

(54) The in-feed device comprises a housing 703 which further comprises an inlet 702, an outlet 706, and a transporting means 704 for transporting a first medium, such as biomass, from the inlet 702 to the outlet 706 (in the direction as shown by arrow B). Preferably, the in-feed device is positioned laterally and biomass material enters the housing 703 through the inlet 702 in the direction of gravity (as shown by arrow A).

(55) Preferably, the transporting means 704 is a screw conveyor driven by a motor 705. However, a pump, such as a centrifugal pump or a positive displacement pump, may be used to transport the biomass from the inlet 702 to the outlet 706.

(56) The outlet 706 through which the biomass exits the in-feeding device is preferably upstream of and in fluid contact with an inlet 707 of the process initiator device.

(57) Preferably, the outlet 706 is shaped such that the cross sectional area of the outlet 706 progressively decreases toward the inlet 707, and preferably still the outlet may be a frusto-conical shape (not shown). This has the effect of compacting the biomass as it traverses the outlet 706 from the in-feeding device I to the process initiator device II (in the direction as shown by arrow B), resulting in a compacted plug of biomass.

(58) In a preferred embodiment of the in-feeding device, the housing 703 and/or the transporting means 704 may be adapted to compact and/or dewater the biomass as said biomass traverses said housing from the inlet 702 to the outlet 706. Preferably, the housing 703 comprises at least one outlet 708 through which water/liquids can exit the housing. The biomass entering the in-feeding device is preferably in the form of a pulp comprising a dry matter content of between 7% and 15%, and the dewatering step preferably increases the dry matter content of the biomass/pulp by at least double, preferably by at least triple, and preferably by at least quadruple.

(59) The biomass exits the in-feed device I through the outlet 706, preferably as a compacted and dewatered plug, and passes into the inlet 707 of the process initiator device II.

(60) The process initiator device II comprises a housing 711 within which is located a rotating means 710, said housing also comprising an inlet 707 for receiving biomass and an outlet 714 to allow processed biomass to exit said housing.

(61) As mentioned above, the rotating means is preferably constituted by a plurality of alternating spacers and discs, wherein the discs are substantially circular with serrations on the outer edges, and wherein channels are located between said spacers and said discs, as shown in FIGS. 5 and 6. The overall arrangement of discs and spacers produces a substantially cylindrical rotating means with protrusions on the outer edge.

(62) The protrusions of the rotating means are adapted to comminute the biomass material entering the housing 711 through inlet 707. Preferably, the protrusions are in the form of cutting blades, but may equally be any suitable shape or appendage which results in the biomass being comminuted (i.e. shredded, milled, ground, etc.). Preferably still, the rotating means may be rotated at 500 to 3000 rotations per minute (rpm). Rotating the rotating means at these speeds produces a protrusion tip velocity of 20-50 m/s, which is preferable in order to adequately comminute the biomass.

(63) At the same time as being comminuted, the biomass is contacted with a second medium. The the second medium may be a heated gas, such as steam, or may be a chemical agent, such as, but not limited to, those listed in Table 2 in liquid or vapour form, or an oxidising agent.

(64) TABLE-US-00001 TABLE 2 Chemical Formula Process pH Action Sulfuric acid H.sub.2SO.sub.4 DASE Acidic Breaks mainly bonds in hemicellulose. Sulfuric acid H.sub.2SO.sub.4 AH Acidic Breaks bonds in hemicellulose and minor cellulose. Sulfur dioxide SO.sub.2 DASE Acidic Breaks mainly bonds in hemicellulose. Hydrochloric acid HCl AH Acidic Breaks bonds in hemicellulose and minor cellulose. Nitric acid HNO.sub.3 DASE Acidic Breaks mainly bonds in hemicellulose. Phosphoric acid H.sub.3PO.sub.4 DASE Acidic Breaks mainly bonds in hemicellulose. Maleic acid HO.sub.2CCHCHCO.sub.2H DASE Acidic Breaks mainly bonds in hemicellulose. Oxalic acid H.sub.2C.sub.2O.sub.4 DASE Acidic Breaks mainly bonds in hemicellulose. Carbon dioxide CO.sub.2 SE Acidic Breaks mainly bonds in hemicellulose. Carbon dioxide CO.sub.2 scCO2 Acidic Modifies lignin. H3BW12O40 H.sub.3BW.sub.12O.sub.40 Heteropolyacids Acidic Cellulose dissolution. Ozone O.sub.3 Ozonolysis Neutral Removal of lignin. No toxic degradation products. Acetic acid CH.sub.3COOH DASE Acidic Breaks mainly bonds in hemicellulose, and some lignin. Acetic acid CH.sub.3COOH Organosolv Acidic Solubilizes lignin. Acetone CH.sub.3COCH.sub.3 Organosolv Acidic Solubilizes lignin. Methanol CH.sub.3OH Organosolv Acidic Solubilizes lignin. Ethanol CH.sub.3CH.sub.2OH Organosolv Acidic Solubilizes lignin. Phenols various Organosolv Acidic Solubilizes lignin. Ethylene glycol C.sub.2H.sub.6O.sub.2 Organosolv Acidic Solubilizes lignin. Tetrahydrofurfuryl C.sub.5H.sub.10O.sub.2 Organosolv Acidic Solubilizes lignin. alcohol Sodium hydroxide NaOH Alkali Alkaline Solubilizes lignin. Removes minor hemicellulose. Calcium hydroxide Ca(OH).sub.2 Alkali Alkaline Solubilizes lignin. Removes minor hemicellulose. Ammonia NH.sub.3 AFEX, ARP, alkali Alkaline Solubilizes lignin. Removes minor hemicellulose. Water H.sub.2O LHW Neutral Breaks mainly bonds in hemicellulose. Methanesulfonic CH3SO3H DASE/MSA Acidic Breaks mainly bonds in hemicellulose acid (MSA) Nitrogen Dioxide NO.sub.2 DASE Acidic Breaks mainly bonds in hemicellulose DASE: Dilute Acid, Steam Explosion AFEX: Ammonia Fibre Expansion AH: Acid Hydrolysis SE: Steam Explosion LHW: Liquid Hot Water ARP: Ammonia Recycling Process SC: Super Critical

(65) The second medium is introduced into the housing 711 through a manifold 714 which is connected to feed lines 713. This is further illustrated in FIGS. 8A and 8B.

(66) Feed lines 713 are connected to the axle/shaft 802 of the rotating means which is adapted to feed the second medium to the channels located between the discs and spacers. Dotted lines 804 schematically illustrate the pathway by which the second medium enters the housing 711.

(67) FIG. 9A shows a cross section schematic of the process of comminuting the biomass whilst simultaneously contacting said biomass with the second medium (in this instance, the second medium is illustrated by the curved arrow 906). Briefly, the biomass enters the housing (not shown in FIG. 9A) through the inlet (not shown) in a direction being parallel to or substantially parallel to a radius of the rotating means, and is brought into contact with the protrusions 910. The second medium is injected through a channel 907 and contacts the biomass in the comminuting region, specifically the recessed zone 908 between adjacent protrusions. In the instance the second medium is a heated gas, a rapid heat transfer occurs between the second medium and the biomass in said recessed zone 908. In the instance the second medium is a chemical agent, a chemical transformation at the surface of the comminuted biomass may occur, such as hydrolysis or oxidation.

(68) FIG. 9B shows a further preferred arrangement of the disks and spacers. The disks are arranged such that each subsequent disk (n+1) is rotated by a constant distance relative to a respective preceding disc (n). This has the effect of off-setting the protrusions on each said subsequent disk relative to each said preceding disc, such that the net effect of said arrangement of protrusions is the formation of well-defined spiralling furrows 902 traversing the rotating means in a longitudinal direction. This arrangement of spiralling furrows: reduces the total force acting on the cylindrical rotating means at any given time (i.e. reduces the impulse on the cylindrical rotating means) whilst said rotating means is comminuting the biomassthis has the effect of smoothing the cutting process (i.e. less erratic/bumpy cutting) and reduces the chance of mechanical failure of the apparatus; and aids in the formation of a fluid flow across the rotating means.

(69) As mentioned above, one of the major advantages of the present apparatus is rapid heating of the biomass. This is primarily achieved by contacting comminuted particles having sufficiently small dimensions with a heated second medium, preferably a heated gas. The rate of heat transfer is primarily dependent on the size of the particles of the comminuted biomass. FIG. 10 shows that reducing the particle size (i.e. increasing the overall surface area) of the biomass significantly reduces the time required to heat the biomass to the desired temperature (i.e. to the temperature of the heated second medium).

(70) Higher dry matter content also increases the rate of heat transfer from the heated second medium to the biomass (for example, see FIG. 11). However, the primary benefit of using a higher dry matter content (i.e. lower water content biomass) is the reduction in energy required to heat the biomass. For example, an increase of from 15% DMC to 30% DMC reduces the amount of energy required to heat 1 kg of wheat straw (specific heat capacity, Cp, 1.5 kJ/kg/K) to the temperature of heated steam from 2896 kJ to 1294 kJ (a reduction of 124%). This reduction in energy is largely due to the reduction in energy that is expended through heating the additional water (Cp 4.18 kJ/kg/K) that is present in the biomass prior to dewatering.

(71) As the rotating means rotates, the protrusions generate a turbulent fluid flow path across the rotating means (as, for example, is schematically illustrated in FIG. 8B by dashed line 904) which assists in both mixing the biomass with the second medium and transporting the biomass from the inlet 707 to the outlet 714. Preferably, the turbulent fluid flow transports the biomass across the rotating means at a rate such that the biomass remains in contact with the rotating means for less than 30 seconds, preferably less than 10 seconds, preferably less than 5 seconds and most preferably less than 3 seconds. The residence time may be controlled by altering the rotation speed of the rotating means, thereby altering the flow rate of the fluid.

(72) Combining the turbulent flow/high flow rate across the rotating means with the rapid heating of the biomass in the recessed zone(s) 908 generates a highly efficient and rapid heat transfer due to forced convection, which consequently produces an even temperature throughout the heated biomass (i.e. there is a minimal temperature gradient throughout the biomass). This rapid and even heating is a significant improvement over the prior art, and is illustrated by FIG. 11, which compares computer generated simulations (using PTC MathCad, see Appendix 1 for details) of the apparatus of the invention (A, wheat straw, with forced convection; B, cubic wood chips with 0.4 cm dimensions, with forced convection) with simulations of a standard batch reactor with steam injection (C, cubic wood chips with 0.4 cm dimensions, no forced convection; D, cubic wood chips with 1 cm dimensions, no forced convection). The forced convection effect, as provided by the apparatus of the invention, allows the wood chips (B) to be heated to a maximum temperature in under a minute, whereas without the forced convection effect (C) the biomass requires more than double the residence time to achieve the same level of heating.

(73) Reducing the contact time of the biomass with the rotating means and heating mechanism reduces the amount of energy required to heat the biomass and also reduces the likelihood of unwanted side reactions from occurring (such as unwanted chemical reactions or burning, both of which result from overheating).

(74) Once the biomass has been comminuted and contacted with the second medium, it passes into a first retention zone 715. In the first retention zone 715 the treated biomass may be contacted with at least one additional processing media that has been introduced into the first retention zone 715 by at least one inlet (not shown). The additional processing media may be a heated gas, such as steam, or may be a chemical agent, such as a chemical as listed in Table 2 (above) or an acid in liquid or vapour form, or an oxidising agent.

(75) Preferably, the biomass may pass through the first retention zone 715 by the action of gravity (in the direction shown by arrow C in FIG. 7). However, the first retention zone 715 may comprise transporting means, such as a pump, to actively transport the processed biomass across the retention zone 715 to the outlet 714.

(76) The biomass exits the process initiator device II via the outlet 714, which may be in fluid contact with a second retention zone III. The biomass exiting device II is at the desired temperature, which is distributed evenly throughout (i.e. isothermal distribution). Generally, the second retention zone III is where the processing of the biomass takes place (chemical alteration e.g. hydrolysis, oxidation, etc.).

(77) Preferably, the treated biomass is retained in the second retention zone for 2 minutes to 60 minutes, preferably 5 minutes to 30 minutes, and most preferably from 10 minutes to 15 minutes. It should be understood that different biomass materials (e.g. wheat straw, woodchips, herbaceous plant materials, etc.) will require different retention times.

(78) Preferably, the second retention zone III is adapted to minimise heat loss from the biomass to the surrounding environment (e.g. the housing is suitably insulated), such that the temperature of the biomass at the outlet 720 is within 5 C., preferably within 4 C., preferably within 3 C., preferably within 2 C., and most preferably within 1 C. of the temperature of the biomass at the outlet 714.

(79) Preferably, the second retention zone comprises transporting means for transporting the treated biomass from the process initiator device II to a reactor (as represented by arrow D). Preferably, the transporting means is a screw conveyor, however any suitable transporting means, such as a centrifugal pump or displacement pump, may be used.

(80) APPENDIX 1- PTC MathCad Simulations

(81) All materials can store heat. Therefore, when a temperature or heat flux change is imposed it takes some time to reach steady state. During this time, a transient analysis must be performed in order to determine temperatures and heat flows. For systems with negligible thermal resistance, a simplified analysis may be performed.

(82) The Biot number (Bi) is a dimensionless number, equal to the ratio of the internal thermal resistance (1/k) to the surface thermal resistance (1/h.Math.L). This number determines whether lumped parameter analysis is applicable and is calculated using equation:

(83) $\mathrm{Bi}=\frac{h.Math.L}{k}\begin{array}{c}\mathrm{where}L\mathrm{is}a\mathrm{characteristic}\mathrm{length}\\ \left(L=\mathrm{Volume}/\mathrm{Area}\right).\end{array}$
h=heat transfer coefficient (W/(m.sup.2.Math. C.)) and k=thermal conductivity (W/(m.Math. C.)).

(84) When Bi is small (<0.1), it can be assumed with reasonable accuracy that the body is isothermal, and lumped parameter analysis can be performed. If Bi<0.1, this implies that the heat conduction inside the body is much faster than the heat convection away from its surface, and temperature gradients are negligible inside of it. This can indicate the applicability of certain methods of solving transient heat transfer problems, such as a lumped-capacitance model of transient heat transfer (also called lumped system analysis).

(85) Thus, in this case, the computational model originates from an energy balance and an assumption that the temperature of the particle is homogenous (i.e. that Bi<0.1).

(86) $-C.Math.\mathrm{dT}=\left(T-T_e\right).Math.\frac{\mathrm{dt}}{R}$
T.sub.e=Temperature of the environment

(87) The thermal capacitance of the body (C) and surface resistance (R) is given by:

(88) $C:=c.Math..Math.V$$\mathrm{and}$$R:=\frac{1}{A.Math.h}$
C=the heat capacity of particle; p=density; V=volume; A=surface area; h=heat transfer coefficient.

(89) From this, the following expression can be obtained:

(90) ${}_i:=\exp \left(-\frac{t_i}{R.Math.C}\right)$

(91) Where the dimensionless time () is given by:

(92) $=\frac{T-T_e}{T_o-T_e}$

(93) From this the temperature (T) of the particle as a function of time (t) is obtained:

(94) $T\left(t\right)=\left(T_0-T_e\right){}^{\left(-\frac{t}{\mathrm{RC}}\right)}+T_e$

(95) An important part of the model is the heat transfer coefficient. The present invention utilises forced convection, whereas the previously known reactors use passive convection. According to Engineering Tool Box (http://www.engineeringtoolbox.com/) the heat transfer coefficient for forced convection is 20-200 W/m.sup.2/K and for free convection is 5-25 W/m.sup.2/K.

(96) In the above calculation 100 W/m.sup.2/K was used for forced convection and 20 W/m.sup.2/K was used for free convection.