FIBRE PROCESSING APPARATUS AND AN ASSOCIATED METHOD

Description

The invention to which this application relates is a fibre processing apparatus for fibre structure modification, in particular, cellulose and ligno-cellulose fibres, and an associated method of modifying said fibres.

The process of modification involves subjecting cellulose and ligno-cellulose fibres to a range of shearing and compression forces. During this process the cell walls of the fibres are restructured, resulting in a microscopically hair-like appearance of the fibre surfaces and/or dependent on source fibre type, a gel-like state. This helps to increase the relative bonded area between fibres, additionally to increase the surface smoothness of a fibre mass. Various techniques are known which are used in the modification of such fibres, be they cellulosic or synthetic. Mechanical processing of the fibres involves subjecting fibres to mechanical components which may cut, grind or otherwise process the fibres through an processor. Compression-based fibre modification applies forces to the fibrous material which act on the network of fibres in the material to separate individual fibres from the network and further modify these fibres. The separation of individual fibres and repeated compression of the fibrous mass results in the modification (restructuring) of the fibrous material. Processing by the use of compression tends to result in more internal modification of the fibres compared with mechanical processing. Further, mechanical fibre modification is known to be heterogeneous whereas compression modification seems to result in a more homogenous treatment of the fibre.

Microfluidization is a method used for production of micro and nanoscale size materials. It is commonly used in pharmaceutical industry to make liposomal products, emulsion and in food industry to produce dairy products. Microfluidizers are also widely used to produce nanofibrillated cellulose (NFC). A microfluidizer uses a pump to create high pressure to disintegrate fibres using shear forces. Fibre suspension is fed into the inlet and then forced through a Y-type or Z-type narrow channel under high pressure. This results in acceleration of the suspension that creates high shear rate and eventually breaks up the fibres. It was reported that increasing the pressure and number of cycles through the microfluidizer or decreasing the size of the chamber increases the degree of modification. High-pressure homogenization is the most widely used method for both small- and large-scale NFC production due to its high efficiency, simplicity and lower cost compared to other alternatives. It involves passing the cellulose fiber-water suspension through a very narrow channel under high pressure. The delamination of fibres is advanced by extremely high shearing forces, high velocity, rapid pressure drops and frictional forces. The degree of cellulose modification depends on the applied pressure and extent of homogenization cycles. NFC produced by high-pressure homogenization have broad fibril diameter distribution, fibril length and high surface area.

There are two main disadvantages of this high-pressure homogenization. First, due to small nozzle pore size clogging is a problem. Thus, it is essential to decrease the fibre size through various pre-treatments before passing it through the system. In addition, the process is energy intensive and therefore scaling up the homogenization process is challenging. One main advantage of microfluidization over high-pressure homogenization is that it is less prone to clogging as it functions at a constant shear rate. In addition, this method provides better reproducibility due to fixed geometry.

Compression therefore, in some circumstances may be utilized as a “pre-treatment” step to further fibre modification, wherein the fibrous material is exposed to pressurization for prolonged periods of around one hour, before being subjected to mechanical work. In some instances, the two approaches may be employed simultaneously, for example in thermo-mechanical pulp (TMP), which uses heated steam pressure and mechanical work simultaneously.

It is therefore an aim of the present invention to provide an improved processing apparatus for the modification of fibre structures, which overcomes the aforementioned problems associated with the prior art.

It is a further aim of the present invention to provide an improved method of modifying fibres, which overcomes the aforementioned problems associated with the prior art.

According to a first aspect of the invention there is provided fibre processing apparatus for the modification fibrous material, said apparatus including:

• • at least one housing body, the housing having an inlet and an outlet through which fibrous material may flow along a flow path, in use;
  • the housing body comprising a plurality of fibre modification sections sequentially arranged along the flow path;
  • one or more rotatable shaft members provided within the housing body and provided to extend along the flow path from a first end in a first modification section to a second, opposing end in a final modification section;
  • wherein a first plurality of said modification sections includes compression and/or pressure-based modification means, and a second plurality of said modification sections includes mechanical modification means.

Typically, said apparatus is configured to permit modification of fibrous material in a linear manner, in use. That is to say, the fibre modification sections are arranged linearly and sequentially.

In some embodiments, the apparatus may include second or further housing bodies, through which fibrous material may be permitted to flow along a flow path thereof.

Preferably, said first and second pluralities of fibre modification sections are arranged in an alternating manner along the flow path. That is to say, if the first modification section provided comprises compression and/or pressure-based modification means, the second, subsequent and adjacent section may employ mechanical modification means, and the following section will once more comprise compression and/or pressure-based modification means. Such an arrangement may be repeated as is required. In other embodiments of the invention, one or more sections comprising compression and/or pressure-based modification means may be provided sequentially, followed by one or more sections comprising mechanical modification means, with such an arrangement repeated as is required. Further typically, the number of mechanical and/or compression/pressure-based modification sections in each sequence may be varied as is required. Thus, in the embodiments of the present invention, the apparatus provides alternating arrangements between sections comprising compression and/or pressure-based modification means and sections comprising mechanical modification means.

In one embodiment, the first fibre modification section is provided to be a compression and/or pressure-based modification section, and a second subsequent section is provided to comprise mechanical modification means. Typically, such a configuration of sections is repeated one or more further times along the flow path and the housing body.

Typically, said compression and/or pressure-based fibre modification sections comprise fluid pressure modification means. Preferably, said fluid is liquid. More preferably, said liquid is water.

Preferably, at least two rotatable shaft members are provided. Typically, the apparatus is provided in the form of a lineal processor.

In one embodiment, a plurality of mechanical fibre modification components is provided on the one or more shaft members. Typically, said mechanical modification components are provided on the one or more shaft members only within the mechanical modification sections.

In one embodiment, each compression fibre modification section includes a fluid inlet means and fluid outlet means. Typically, said compression modification sections are arranged to create a build-up of fluid pressure within each respective section, which serves to act upon and modify the fibrous material, in use. In some embodiments, said fibrous material may comprise a moisture content sufficiently high such that no fluid inflow is required in the first compression section. Typically, therefore, in some embodiments, in a first compression section, fluid inlet means may or may not be provided.

In one embodiment, said compression fibre modification sections are arranged to impart a fluid pressure of up to 350 bar. In some embodiments, said compression fibre modification sections may be arranged to impart a fluid pressure of up to 700 bar. Typically, as fibrous material is introduced into the compression fibre modification sections, the sections are arranged to impart an initial pressure of 0-70 bar.

In some embodiments, said fluid introduced into said compression fibre modification sections may be water. Typically, the water may be additionally treated with or include further chemicals or additives to aid in the fibre modification process.

Typically, said water is arranged to be introduced into said compression fibre modification sections at a temperature between 1° C. and 100° C. In some embodiments, the water may be arranged to be heated up to approximately 374° C. under a pressure of approximately 217 bar.

Typically, the arrangement and sequencing of the sections of the apparatus serve to enable the build-up of back-pressure in the compression fibre modification sections.

In one embodiment, the fluid injected into the compression fibre modification sections is arranged to exit said sections through fluid outlet means. Typically, fluid exiting through said outlet means may subsequently be recycled or reused in or with the apparatus.

In some embodiments, at least one water jet-cutting section may be provided. Typically, said section is located prior to the first compression fibre modification and mechanical fibre modification sections. Typically, said water jet-cutting section is provided to act as a fibre reducing means.

The present invention therefore provides separate and sequential compression and mechanical fibre modification stages, wherein said stages are alternately repeated one or more times. In some preferred embodiments, at least three compression fibre modification sections and three mechanical fibre modification sections are provided in an alternating arrangement in the apparatus.

In one embodiment, each compression fibre modification section may be arranged to modify and/or pressurize the fibrous material for a predetermined period of time, in use. In some embodiments, said predetermined period of time may be provided as “high-speed”, in a period of between 5-30 seconds; “standard” in a period of between 30-60 seconds; or “extended” in a period of 60-180 seconds. Pressurizing the fibrous material for shorter time periods of between 5-30 seconds, 30-60 seconds, or 60-180 seconds is achieved alongside the provision of increased flow rates of the material through the sections according to the desired time period, and particularly increased in comparison to pressurization techniques employed in pre-treatment steps in the prior art, which subjects the fibrous material to periods of pressure of around an hour.

Typically, the apparatus is arranged to have a target flow rate per hour of wet material with a solid content, at a low range of between 5%-20%; at a standard range of between 20%-30%; at a high range of between 30%-40%; and/or at an extra high range of between 40%-70%, which depends on the diameter of the fibre processor apparatus. Typically, wet material with solid content in the high an extra high ranges may be further wetted via the injection of fluid in the compressing fibre modification section or sections. Preferably, said target flow rates are approximately as follows:

• • 60 mm diameter fibre processing apparatus: approximately 1.5 tons/hour;
  • 70 mm diameter fibre processing apparatus: approximately 2.5 tons/hour;
  • 80 mm diameter fibre processing apparatus: approximately 4 tons/hour;
  • 90 mm diameter fibre processing apparatus: approximately 6 tons/hour;
  • 100 mm diameter fibre processing apparatus: approximately 8 tons/hour.

In one embodiment, the apparatus may include one or more further inlet means. Typically, said further inlet means are provided located with at least one of the fibre modification sections.

In some embodiments, said one or more further inlet means may be provided located in with a section intermediate two fibre modification sections.

Preferably, said one or more further inlet means are arranged to permit the input of additional material into the apparatus and thus mix with the fibrous material, in use.

Typically, said one or more further inlet means are provided to permit the introduction of additional material such as any or any combination of fibres, minerals, pigments and/or chemicals to the fibrous material, in use.

The introduction of such materials may be done so incrementally and such materials are added in order to improve the final product characteristics, depending on what is required of the final processed product. Typically, such incremental introduction may be affected through a single further inlet means, or in other embodiments over two or more further inlet means located along the apparatus, as required.

Typically, at least two rotatable shaft members are provided and, within the mechanical fibre modification sections, selected mechanical components are provided on each of said rotatable shaft members.

Preferably, two rotatable shaft members are provided in the processing apparatus. In some embodiments, said rotatable shaft members are arranged to be co-rotating. In other embodiments, said rotatable shaft members may be arranged to be counter-rotating. Typically, the fibre modification components on each rotatable shaft are provided to be complementary and intermeshing.

In some embodiments, various types of fibre modification components may be provided on the one or more rotatable shaft members within each mechanical fibre modification section and/or from section to section.

Typically, the mechanical fibre modification components may be variable and/or replaceable depending on the desired fibre morphology.

Preferably, said compression fibre modification section form at least 50% of the fibre modification sections along the flow path of the apparatus. Typically, at least 50% of the fibre modification/processing periods to which the fibrous material is subjected is fluid pressure modification. Typically, said fluid pressure is liquid pressure.

In one embodiment, said compression fibre modification sections comprise: a pressure build-up stage; a filter stage; and a back-pressure stage. Typically, said fluid inlet means are located at the build-up stage. Preferably, pressure is provided to be highest in the back-pressure stage and lowest in the pressure build-up stage.

In one embodiment, one or more filter and/or degassing sections may be provided, each located intermediate a compression fibre modification section and a mechanical fibre modification section. Typically, said filter and/or degassing sections may be located downstream of a compression fibre modification section and upstream of a mechanical fibre modification section. That is to say, in some embodiments, after passing through the mechanical fibre modification section, the fibrous material may move immediately into a further compression fibre modification section, and only through a filter and/or degassing section after passing through a compression fibre modification section.

The present invention is therefore advantageous in that the repeated, alternating, sequential steps of compression and mechanical fibre modification of the fibrous material results in less fibre width reduction and overall, less physical damage to the fibres. The apparatus also encourages more homogeneous fibre modification and internal fibre modification. Further, in combining the two modification techniques, the mechanical fibre modification components of the rotatable shaft members suffer far less wear as compared to traditional mechanical fibre modification apparatus, or systems wherein the fibrous material is merely pre-treated under pressure, and then subjected to mechanical modification.

In one embodiment, the mechanical fibre modification components are located on and along the one or more rotatable shaft members across the mechanical fibre modification sections. Typically, said mechanical fibre modification components are located to substantially abut a wall or partition separating the compression fibre modification section from the mechanical fibre modification section. The closely arranged manner of the mechanical fibre modification components with respect to each other and also to the wall/partition between sections aids in the build-up of back-pressure in the compression fibre modification sections.

In one embodiment, a plurality of bearing members is arranged to provide mechanical engagement between the housing body and the one or more rotatable shaft members, or components provided thereon. Typically, the plurality of bearing members is provided located within the housing body and arranged to engage the one or more rotatable shaft members, or components provided thereon.

In preferred embodiments, the bearing members are provided as cassette bearing members. Typically, one or more pluralities of cassette bearing members are provided to be located about the one or more rotatable shaft members and/or one or more components provided thereon, at one or more points along a length of the one or more shafts. Preferably, where at least two rotatable shaft members are provided, bearing members are provided engaged with each rotatable shaft member and/or components provided thereon at equivalent points along the lengths of said shafts.

Typically, one or more annular recesses or channels may be formed in the interior walls of the housing body, arranged to receive at least a portion of said cassette bearing members.

Typically, said cassette bearing members are located intermediate first and second opposing ends of the one or more rotatable shaft members within the housing body. Further typically, said bearing members are provided to support the one or more rotatable shaft members at one or more points along the length thereof.

In conventional fibre processing apparatus, the shafts are supported at each of the opposing ends only. This can lead to bowing of the shaft assemblies towards the centre under the combination of its own weight and the weight of the mechanical fibre processing components provided thereon. In the present apparatus, this problem is alleviated by the provision of one or more pluralities of cassette bearing members, located at one or more points along the length of the one or more rotatable shaft members.

Consequently, the one or more rotatable shaft members may therefore be held and retained more accurately in position along the processing channel of the apparatus, keeping the same straight and preventing the occurrence of any bowing. This, in turn, prevents or at least substantially reduces the formation of gaps between the mechanical fibre modification components on the rotatable shaft members and between the components and the abutting wall or partition, thereby improving and aiding the build-up of back-pressure in the compression fibre modification sections and improving the overall fibre modification process. Further, by providing the cassette bearing members at specific and strategic points within the housing to support the one or more rotatable shaft members, this serves to increase the longevity of the rotatable shaft members and mechanical fibre modification components provided thereon, reducing wear and tear over time to them.

In another aspect of the present invention, there is provided a method of modifying fibrous material, the method including the steps of:

• • introducing a fibrous material for modification into an inlet of an apparatus as described above;
  • the fibrous material entering a first compression and/or pressure-based fibre modification section and being subjected to compression and/or pressure-based fibre modification;
  • the fibrous material exiting the first compression and/or pressure-based fibre modification section and subsequently entering a mechanical fibre modification section and being subjected to mechanical fibre modification;
  • wherein the fibrous material passes sequentially through one or more further alternating arrangements of compression and/or pressure-based fibre modification sections and mechanical fibre modification sections, subsequently exiting the apparatus through an outlet.

In some embodiments, the apparatus may include second or further housing bodies, through which fibrous material may be permitted to flow along a flow path thereof.

In some embodiments of the invention, one or more sections comprising compression and/or pressure-based modification means may be provided sequentially, followed by one or more sections comprising mechanical modification means, with such an arrangement repeated as is required. Further typically, the number of mechanical and/or compression/pressure-based modification sections in each sequence may be varied as is required.

Typically, the fibrous material passes through sequential fibre modification sections of the apparatus alternating between compression and/or pressure-based fibre modification means, and mechanical fibre modification means.

In a preferred embodiment, at least three compression and/or pressure-based fibre modification sections are provided alternating with at least three mechanical fibre modification sections.

Typically, said compression and/or pressure-based fibre modification sections employ liquid pressure fibre modification. Typically, said liquid is water.

In one embodiment, said compression fibre modification sections impart a fluid pressure of up to 350 bar. In some embodiments, said compression fibre modification sections may impart a fluid pressure of up to 700 bar. Typically, as fibrous material is introduced into the compression fibre modification sections, the sections impart an initial pressure of 0-70 bar.

In some embodiments, the fibrous material may be subjected to at least one water jet-cutting section. Typically, said section is located prior to the first compression fibre modification and mechanical fibre modification sections. Typically, said water jet-cutting section acts as a fibre reducing means.

In some embodiments, said fluid introduced into said compression fibre modification sections may be water. Typically, the water may be additionally treated with or include further chemicals or additives to aid in the fibre modification process.

Typically, said water is introduced into said compression fibre modification sections at a temperature between 1° C. and 100° C. In some embodiments, the water may heated up to approximately 374° C. under a pressure of approximately 217 bar.

In one embodiment, each compression fibre modification section modifies and/or pressurizes the fibrous material for a predetermined period of time. Typically, said predetermined period of time is between 5-300 seconds.

In one embodiment, said compression fibre modification sections comprise: a pressure build-up stage; a filter stage; and a back-pressure stage and typically, pressure is provided to be highest in the back-pressure stage and lowest in the outlet stage.

Typically, said fibrous material has a dry content in the region of 20%-25% prior to introduction into the apparatus. Preferably, the dry content of the modified/processed fibrous material is in the region of 40%-50%. By increasing the dry content to these levels, this makes any subsequent processing and use of the fibrous material more efficient.

Typically, the method includes having a target flow rate per hour of wet material with a solid content, at a low range of between 5%-20%; at a standard range of between 20%-30%; at a high range of between 30%-40%; and/or at an extra high range of between 40%-70%, which depends on the diameter of the fibre processor apparatus. Typically, wet material with solid content in the high an extra high ranges may be further wetted via the injection of fluid in the compressing fibre modification section or sections. Preferably, said target flow rates are approximately as follows:

• • 60 mm diameter fibre processing apparatus: approximately 1.5 tons/hour;
  • 70 mm diameter fibre processing apparatus: approximately 2.5 tons/hour;
  • 80 mm diameter fibre processing apparatus: approximately 4 tons/hour;
  • 90 mm diameter fibre processing apparatus: approximately 6 tons/hour;
  • 100 mm diameter fibre processing apparatus: approximately 8 tons/hour.

In one embodiment, the apparatus may include one or more further inlet means which permits the input of additional material into the apparatus and thus mix with the fibrous material.

Typically, said further inlet means are provided located with at least one of the fibre modification sections.

In some embodiments, said one or more further inlet means may be provided located in with a section intermediate two fibre modification sections.

Typically, the additional material introduced may be in the form of any or any combination of fibres, minerals, pigments and/or chemicals to the fibrous material.

Typically, the introduction of such materials is done so incrementally and such materials are added in order to improve the final product characteristics, depending on what is required of the final processed product. Typically, such incremental introduction may be affected through a single further inlet means, or in other embodiments over two or more further inlet means located along the apparatus, as required.

In one embodiment, the modified/processed fibrous material has a Schopper-Riegler (SR) value of between 10-15%.

According to another aspect of the invention there is provided fibre processing apparatus for the modification fibrous material, said apparatus including:

• • at least one housing body, the housing having an inlet and an outlet through which fibrous material may flow along a flow path, in use;
  • one or more rotatable shaft members provided within the housing body and provided to extend along the flow path from a first end to a second, opposing end;
  • wherein a plurality of bearing members is arranged to provide mechanical engagement between the housing body and the one or more rotatable shaft members, or components provided thereon.

In preferred embodiments, the bearing members are provided as cassette bearing members. Typically, one or more pluralities of cassette bearing members are provided to be located about the one or more rotatable shaft members and/or one or more components provided thereon, at one or more points along a length of the one or more shafts. Preferably, where at least two rotatable shaft members are provided, bearing members are provided engaged with each rotatable shaft member and/or components provided thereon at equivalent points along the lengths of said shafts.

In other embodiments, the plurality of bearing members is provided located within the housing body and arranged to engage the one or more rotatable shaft members, or components provided thereon.

Typically, said cassette bearing members are located intermediate first and second opposing ends of the one or more rotatable shaft members within the housing body. Further typically, said cassette bearing members are provided to support the one or more rotatable shaft members at one or more points along the length thereof.

In one embodiment, the housing body comprises a plurality of fibre modification sections sequentially arranged along the flow path. Typically, the one or more rotatable shaft members provided within the housing body are provided to extend along the flow path from a first end in a first modification section to a second, opposing end in a final modification section.

Typically, a first plurality of said modification sections includes compression and/or pressure-based modification means, and a second plurality of said modification sections includes mechanical modification means.

Embodiments of the present invention will now be described with reference to the accompanying figures, wherein:

FIG. 1 illustrates a schematic of a fibre processing apparatus for modifying fibrous material, in accordance with an embodiment of the present invention;

FIG. 2 illustrates a schematic of a number of fibre modification sections within a housing body of a fibre processing apparatus for modifying fibrous material, in accordance with an embodiment of the present invention;

FIGS. 3a-b illustrate the provision of a plurality of cassette bearing members within a housing body of a fibre processing apparatus for modifying fibrous material, in accordance with an embodiment of the present invention; and

FIGS. 4a-b illustrate views of a section of a rotatable shaft assembly with mechanical components provided thereon in a housing body of a fibre processing apparatus, in accordance with an embodiment of the present invention.

Referring now to the figures, and firstly to FIG. 1, there is shown a fibre processing apparatus 1 provided to process and modify fibrous material that is required to be processed for subsequent use. The apparatus includes a housing body 3 wherein at a first end thereof there is provided an inlet 5 for introducing the fibrous material to the apparatus 1. The material travels along a flow path through the apparatus 1 and at the opposing end of the housing 3, there is provided an outlet 7 through which the processed fibrous material exits the apparatus 1. Extending along the flow path within the housing 3 there are provided one or more rotatable shaft assemblies which serve to mechanically act upon and modify the fibrous material at certain points within the housing 3. In preferred embodiments, two shafts are provided in the form of a linear fibre processor. The housing 3 comprises a number of distinct fibre modification sections provided sequentially along its length. The fibre modification sections are provided in two distinct forms: a first plurality of the sections 9 include compression or pressure-based fibre modification means. Typically, these sections 9 apply liquid pressure fibre modification/processing to the fibrous material as it passes through those sections. A second plurality of the sections 11 include mechanical fibre modification means. Within the mechanical fibre modification sections 11 the shaft assemblies are provided with a series of mechanical fibre modification components thereon, which serve to physically act upon and process the fibrous material as it passes through those sections.

As mentioned above, the sections 9, 11 are arranged sequentially along the length of the housing 3, but also, they are provided in an alternating arrangement. That is to say, for example, in a first embodiment shown in FIG. 1, after the material is fed in through the inlet port 5, it first undergoes liquid pressure fibre modification through the pressure fibre modification section 9, and subsequently flows into the mechanical fibre modification section 11 wherein it undergoes mechanical fibre modification. This process may then be repeated one or more times as the material flows into a second pressure fibre modification section, a second mechanical fibre modification section and so on as is required or provided by the specific apparatus 1. Importantly, though, it is the sequential, alternating flow from liquid pressure fibre modification to mechanical fibre modification etc., which ultimately provides for a greatly improved fibre modification process of the material. In some embodiments, they may be provided, for example, one, two or more consecutive pressure fibre modification sections 9 followed by one, two or more mechanical fibre modification sections 11, which sequence, or a variation thereof, is subsequently repeated. In such embodiments, the alternating arrangement remains, however, greater emphasis is preferably placed on the pressure fibre modification sections 9 of the apparatus 1.

The pressure fibre modification sections 9 each include a liquid inlet port 13 and in preferred embodiments the liquid input is water. In some embodiments, the water may be additionally treated with or include further chemicals or additives to aid in the fibre modification process. Further, there may be provided a water/mineral mix, and such variations will depend ultimately on the fibrous material which is being processed in the apparatus 1 and the specific requirements thereof. The water pressure is allowed to build up in each section and the water-fibrous material mixture is filtered as it passes through. Back-pressure pressure builds up towards the exit point of the pressure fibre modification section 9 which further acts upon and processes the fibrous material before it ultimately exits into the mechanical fibre modification section. The water/filtrate exits the pressure fibre modification sections 9 through a liquid outlet port 15 and can subsequently be recycled and/or re-used as required. FIG. 2 illustrates a further schematic of the housing 3, wherein the pressure fibre modification sections 9 are shown to be further broken down into a pressure build-up stage 17; a filter stage 19; and a back-pressure stage 21, the inlet port 13 feeding into the build-up stage 17. Pressure is provided to be highest in the back-pressure stage 21 and lowest in the pressure build-up stage 17. Pressures will vary in pressure fibre modification section 9 from low at the start/inlet, emerging back into filter area, up to very high as compaction takes place when the fibre enters the back-pressure stage 21. Each of the pressure fibre modification sections 9 are provided to act upon/pressurize the fibrous material for a predetermined period of time, typically, 30-60 seconds. That is to say, the flow rate of the material through the apparatus 1 is such that it will pass through the pressure fibre modification sections in around 30-60 seconds, before moving on to mechanical modification, and on again to further rounds of pressure fibre modification. In pressurizing the fibrous material for short period in this manner, this differs substantially from pressurization techniques employed in pre-treatment steps in the prior art, which subjects the fibrous material to a single period of pressure of around an hour. In practice, the energy requirements for the pressure to backpressure fibre modification are generally regulated to be maintained within commercially acceptable levels. In instances where the pressure may approach to high a level, in some embodiments of the invention, the pressure fibre modification sections 9 may include one or more slots therein, which may be utilised to reduce the pressure and thus energy consumption at a particular time.

In some embodiments of the invention (not shown), the apparatus 1 may include one or more further inlets, which may be provided either as direct inlets into one or more of the fibre modification sections, or into one or more further sections each located intermediate two fibre modification sections. Such inlets may be provided to permit the injection of additional material into the apparatus and subsequently mix with the fibrous material therein while it is being processed. The additional material may be in the form of any or any combination of fibres, minerals, pigments and/or chemicals, which are added so as to improve the final product characteristics, depending on what is desired for a particular composition. The materials may be added incrementally, either through a single further inlet, or in other embodiments, over two or more further inlet means located along the apparatus 1, as required.

As mentioned above, in preferred embodiments, the apparatus 1 comprises a dual-shaft fibre processing apparatus along which are positioned a series of fibre modification components. These are present along the shaft assemblies through the mechanical fibre modification sections 11 but, in some embodiments of the invention, absent through the pressure fibre modification sections 9. In other embodiments of the invention, it is also possible to provide one or more of the pressure fibre modification sections 9 to have “mixed characteristics”, that is to say, one or more components may be provided on the shaft or shafts within at least one of the pressure fibre modification sections 9, which serve to provide physical/mechanical fibre modification simultaneously with the application of pressure, and modification in that manner. Depending on the requirements of the apparatus 1 and the material to be processed, the dual-shaft assembly may comprise co-rotating shaft members or counter-rotating shaft members. The components positioned on a first shaft are provided to be complementary and intermesh with components positioned on the second shaft. The components themselves may be provided in various forms and shapes so as to act upon the fibrous material in differing manners to optimize the fibre modification process. The mechanical fibre modification components are located along the dual-shaft assembly within the fibre modification section 11 to closely abut one another and abut the walls or partitions separating the mechanical and pressure fibre modification sections. This closely arranged manner of the components with respect to each other and also to the wall/partition between sections aids in the build-up of back-pressure in the pressure fibre modification sections 9 and therefore optimize the pressure fibre modification stages in the process. The apparatus 1 comprises a combination of sequentially and alternately arranged mechanical and pressure fibre modification sections, and in preferred embodiments of the invention, the pressure fibre modification sections 9 form at least 50% of those sections such that throughout the fibre modification process the fibrous material undergoes, at least 50% of that process involves liquid pressure fibre modification.

The present invention is therefore particularly advantageous in that the repeated, alternating, sequential steps of pressure and mechanical fibre modification of the fibrous material results in less fibre width reduction and overall, less physical damage to the fibres. The apparatus 1 of the invention also encourages more homogeneous fibre modification and internal fibre modification. Further, in combining the two fibre modification techniques, the mechanical components of the shaft assemblies suffer far less wear as compared to traditional mechanical fibre modification apparatus, or systems wherein the fibrous material is merely pre-treated under pressure, and then subjected to mechanical modification.

Another feature of the present invention is the provision of one or more series of bearings 23 arranged to provide mechanical engagement between the housing 3 and the one or more rotatable shafts, or components provided thereon. The bearings 23 in some embodiments can be located within the housing 3 and around the channel 25 through which the one or more shaft members and associated components extend. This is shown in more detail in FIGS. 3a-b. FIG. 3a shows the location of, in this embodiment, a fibre processing channel 25 within the housing 3 through which two shaft members may extend, and an example of one shaft member component 27 in position within that channel 25 and which contacts a series of cassette bearings 23 located around the wall 29 of the channel 25. The bearings 23 are located as a group extending around the channel wall 29 and engaging the shaft member component 27 at a position intermediate the first and second opposing ends of the shaft member. In some embodiments two or more groupings of bearings 23 may be provided at two or more points along the length of the shaft member within the housing 3. In some embodiments of the invention, the bearings 23 are located with the one or more shafts, or components 27 provided thereon, and are arranged to engage interior walls 29 of the housing 3. One or more annular recesses or channels (not shown) may be formed in the interior walls of the housing 3, arranged to receive the outer or radially distal portion or edge of a component 27 provided on the shafts therein, and which includes a series of bearings 23 provided thereon. The component or components which include the bearings 23 are provided to be enlarged with respect to other components to extend into the recess or channel in the interior walls of the housing 3.

The provision of such series of bearings 23 serves to support the shaft members in position and prevent any undesirable bowing of the shaft assembly. For example, in conventional shaft assemblies, the shafts are supported at each of the opposing ends only. This can lead to bowing of the shafts towards their centre under the combination of their own weight and the weight of the mechanical components provided thereon. This problem is alleviated in the present invention by the provision of one or more groupings of the bearings 23 described above.

FIG. 4 illustrates a further embodiment of the invention wherein, in this example a dual-shaft fibre processing apparatus is shown, the shafts 31 include at least two distinct types of component provided thereon: the first components 33 have varying forms/formations thereon/shapes and are used to act upon and process the fibrous material passing through the apparatus 1; the second component type 35 is provided with a smooth exterior face and these are positioned to engage the cassette bearings 23 (not shown in FIG. 4) located at equivalent points in the channel wall 29. Consequently, the shafts provided in the housing 3 can therefore be held and retained far more accurately in position along the processing channel 25 of the apparatus 1 keeping the same straight and preventing the occurrence of any bowing. This, in turn, prevents or at least substantially reduces the formation of gaps 37 between the components 33 on the shafts 31 and between the components and the abutting wall or partition between sections 9, 11, thereby improving and aiding the build-up of back-pressure in the pressure fibre modification sections 9, and improving the overall fibre modification process. The provision of the bearings 23 also further serves to increase the longevity of the shafts and components, reducing wear and tear over time to them.

In instances where one or more of the pressure fibre modification sections 9 are provided as having “mixed characteristics”, one or more sets of components 35′ may be provided on the shaft or shafts within at least one of the pressure fibre modification sections 9. These may be provided in differing forms and/or arrangements from those components 33 located throughout the mechanical fibre modification sections 11. In particular, the form and arrangement of the components 33′ in the pressure fibre modification sections 9 may be tailored according to which part of that section 9 in which they are located as their particular requirements and purpose may differ somewhat between, for example, those provided in the build-up stage 17 and those provided in the back-pressure stage 21, where pressure is at its highest and thus the components 33′ in that stage may be required to be more tightly packed to aid in the increase in back-pressure. Further, within the mechanical fibre modification sections 11, in some embodiments of the invention, it may also be possible to form two or more distinct stages within those sections, wherein the components 33 may be varied in form, arrangement, density and/or the like, in order to achieve a variation in mechanical fibre modification processes on the fibrous material.

In some further embodiments of the present invention, while not shown in the present figures, the apparatus 1 may further include one or more filter and/or degassing sections, located intermediate the pressure fibre modification sections 9 and the mechanical fibre modification sections 11. In some embodiments, such filter and/or degassing sections may be located downstream of a pressure fibre modification section 9 upstream of a mechanical fibre modification section 11. That is to say, in some embodiments, after passing through the mechanical fibre modification section 11, the fibrous material may move immediately into a further pressure fibre modification section 9, and only through a filter and/or degassing section after passing through a pressure fibre modification section 9.

As it is fed into the apparatus 1, the fibrous material to be modified and processed typically has a dry content in the region of 20%-25% for silage/soaked/washed/sludge; 26-40% for shive/stalks; 40-55% for straws/grasses/beets/industrially produced cellulose; 56-75% for stems/beets; and 75%-99% for all pre-dried cellulose-ligno cellulose fibres including stems/beets. For fibrous material having a dry content in the region of 20%-25% (silage/soaked/washed/sludge) prior to processing, after processing through the apparatus 1 of the present invention, the dry content of that material will now be in the region of 40%-50%—by increasing the dry content to these levels, this makes any subsequent processing and use of the fibrous material more efficient. Further, this modified and processed fibrous material (silage/soaked/washed/sludge) will have a Schopper-Riegler (SR) value of between 30°-40°, and more preferably, of between 33°-38°. Further macro-micro modification of “flexible/robust” ligno-cellulose and standard cellulose fibres can result in SR values of up to 86°. SR ranges of processed material, depending on the make-up of that material, are provided below:

• • De-inking sludge: 6-30°
  • Standard Soft/Hardwood cellulose: 12°-86°
  • Straws/Shiv/Stalks: (preferred) 10-25°, 26°-40°, 41°-55°
  • Grasses: (preferred) 10-30°, 31-45°
  • Stems/Beets: (18-25°, 26°40° 41°-55°, 41°-55°, 55-70°, 70-86°).

The fibre lengths in the final compositions are generally distributed in a skewed bell curve, with the compositions comprising, by weight:

• • (a) 15% to 25% fibres of a length weighted average fibre length of 0.001 mm to 0.2 mm;
  • (b) 40% to 60% (preferably 45% to 55%) fibres of a length weighted average fibre length of 0.2 mm to 0.5 mm;
  • (c) 8% to 35% (preferably 20% to 30%) fibres of a length weighted average fibre length of 0.5 mm to 1.2; and
  • (d) less than 3% (preferably less than 1%) fibres of a length weighted average fibre length of 1.2 mm to 2.0 mm.

Thus, the composition consists of a significant amount of fines (fibre length <0.2 mm) mixed with short length fibres (fibre length of 0.2-1.2 mm). Additionally, the compositions may have a high degree of modification indicated by a high Water Retention Value (WRV) of 600-2000%, preferably, 700-1300%.

The apparatus 1 further includes a control panel 39 with a user interface provided thereon, enabling a user to control the various parameters of the apparatus 1 such as the flow rate, pressure range in the pressure fibre modification sections 9, direction and rate of rotation of the shaft assembly or assemblies and the like, ensuring an optimally modified material at the end of the process.

A further key advantage for this apparatus 1 relates to silica or other abrasive mineral containing ligno-cellulosic fibres. Wear on the shaft assemblies and components for mechanical processing will be avoided due simply to less contact with components in the present invention as these are substituted by the pressure fibre modification sections 9.

Table 1 below on the following pages serves to illustrate, in a non-limiting manner, the various properties and parameters of an apparatus 1 in accordance with the present invention, and its associated sections and stages. By way of example, three fibrous material types have been described, although the skilled person will appreciate further types, as discussed above, are clearly possible to be fed through the apparatus 1.

TABLE 1
properties and parameters of an apparatus 1 and its associated sections and stages, in accordance with an embodiment of the present invention.

PROCESS	Starter	Pressure	Pressure	Pressure		Mechanical	Mechanical	Mechanical
POSITION	Material/	modification	modification	modification	Filter/	modification	modification	modification
PARAM-	Extruder	section 9,	section 9,	section 9,	Degassing	section 11,	section 11,	section 11,
ETERS	Feed Zone	stage 17	stage 19	stage 21	Sections.	stage A	stage B	stage C
Material Type/s	1. Agricultural/	1. Agricultural/	1. Agricultural/	1. Agricultural/	1. Agricultural/	1. Agricultural/	1. Agricultural/	1. Agricultural/
	Wild	Wild	Wild	Wild	Wild	Wild	Wild	Wild
	Lignocellulose	Lignocellulose	Lignocellulose	Lignocellulose	Lignocellulose	Lignocellulose	Lignocellulose	Lignocellulose
	Fibres	Fibres	Fibres	Fibres	Fibres	Fibres	Fibres	Fibres
	2. Industrially	2. Industrially	2. Industrially	2. Industrially	2. Industrially	2. Industrially	2. Industrially	2. Industrially
	Produced	Produced	Produced	Produced	Produced	Produced	Produced	Produced
	Cellulose	Cellulose	Cellulose	Cellulose	Cellulose	Cellulose	Cellulose	Cellulose
	3. Recycled	3. Recycled	3. Recycled	3. Recycled	3. Recycled	3. Recycled	3. Recycled	3. Recycled
	cellulose/	cellulose/	cellulose/	cellulose/	cellulose/	cellulose/	cellulose/	cellulose/
	lignocellulose	lignocellulose	lignocellulose	lignocellulose	lignocellulose	lignocellulose	lignocellulose	lignocellulose
	fibres	fibres	fibres	fibres	fibres	fibres	fibres	fibres
Fibre	1-100	1-100	1-100	1-100	1-100	1-100	1-100	1-100
Throughput	100-500	100-500	100-500	100-500	100-500	100-500	100-500	100-500
(Wet)	500-1000	500-1000	500-1000	500-1000	500-1000	500-1000	500-1000	500-1000
KG per hour	1000-2000	1000-2000	1000-2000	1000-2000	1000-2000	1000-2000	1000-2000	1000-2000
	2000-5000	2000-5000	2000-5000	2000-5000	2000-5000	2000-5000	2000-5000	2000-5000
	5000-10000	5000-10000	5000-10000	5000-10000	5000-10000	5000-10000	5000-10000	5000-10000
	10000-20000	10000-20000	10000-20000	10000-20000	10000-20000	10000-20000	10000-20000	10000-20000
Screw RPM	50-1500	50-1500	50-1500	50-1500	50-1500	50-1500	50-1500	50-1500
range

Screw/	40-50	mm	40-50	mm	40-50	mm	40-50	mm	40-50	mm	40-50	mm	40-50	mm	40-50	mm
Components	50-60	mm	50-60	mm	50-60	mm	50-60	mm	50-60	mm	50-60	mm	50-60	mm	50-60	mm
diameter	60-70	mm	60-70	mm	60-70	mm	60-70	mm	60-70	mm	60-70	mm	60-70	mm	60-70	mm
	70-80	mm	70-80	mm	70-80	mm	70-80	mm	70-80	mm	70-80	mm	70-80	mm	70-80	mm
	80-90	mm	80-90	mm	80-90	mm	80-90	mm	80-90	mm	80-90	mm	80-90	mm	80-90	mm
	90-100	mm	90-100	mm	90-100	mm	90-100	mm	90-100	mm	90-100	mm	90-100	mm	90-100	mm
	100-110	mm	100-110	mm	100-110	mm	100-110	mm	100-110	mm	100-110	mm	100-110	mm	100-110	mm
	110-120	mm	110-120	mm	110-120	mm	110-120	mm	110-120	mm	110-120	mm	110-120	mm	110-120	mm

Solid Content	1-99%	1-99%	1-99%	1-99%	1-99%	1-99%	1-99%	1-99%
Housing	1-100	1-100
Pressure/s		100-250
(Bar)
Fluid/Steam		1-10
input pressure		10-50
(Bar)		50-100
		100-250
		250-500
		500-1000
		1000-3000
Barrel	1-20	1-20	1-20	1-20	1-20	1-20	1-20	1-20
Temperature	20-35	20-35	20-35	20-35	20-35	20-35	20-35	20-35
(° C.)	35-50	35-50	35-50	35-50	35-50	35-50	35-50	35-50
	50-75	50-75	50-75	50-75	50-75	50-75	50-75	50-75
	75-100	75-100	75-100	75-100	75-100	75-100	75-100	75-100
	100-150	100-150	100-150	100-150	100-150	100-150	100-150	100-150
	150-250	150-250	150-250	150-250	150-250	150-250	150-250	150-250
	250-500	250-500	250-500	250-500	250-500	250-500	250-500	250-500
Material (Wet)	1-20	1-20	1-20	1-20	1-20	1-20	1-20	1-20
Temperature	20-35	20-35	20-35	20-35	20-35	20-35	20-35	20-35
(° C.)	35-50	35-50	35-50	35-50	35-50	35-50	35-50	35-50
	50-75	50-75	50-75	50-75	50-75	50-75	50-75	50-75
	75-100	75-100	75-100	75-100	75-100	75-100	75-100	75-100
	100-150	100-150	100-150	100-150	100-150	100-150	100-150	100-150
	150-250	150-250	150-250	150-250	150-250	150-250	150-250	150-250
	250-500	250-500	250-500	250-500	250-500	250-500	250-500	250-500
Water Feed		1-20	1-20	1-20
Temperature		20-100	20-100	20-100
(° C.)		100-200	100-200	100-200
		200-500	200-500	200-500
Ratio of Fluid		1:1-1:5	1:1-1:5	1:1-1:5
Feed to		1:5-1:10	1:5-1:10	1:5-1:10
Kilograms Wet		1:10-1:50	1:10-1:50	1:10-1:50
Fibre per hour		1:50-1:100	1:50-1:100	1:50-1:100
Water Flow		1-3	1-3	1-3
rate for		3-10	3-10	3-10
Pressure and		10-50	10-50	10-50
Cutting		50-100	50-100	50-100
Purposes		100-250	100-250	100-250
(Litres Per		250-500	250-500	250-500
Minute)		500-1000	500-1000	500-1000
Exit Fluid/		0-1	0-1	0-1	0-1
Steam quantity/		1-3	1-3	1-3	1-3
(Litres		3-10	3-10	3-10	3-10
per minute)		10-50	10-50	10-50	10-50
		50-100	50-100	50-100	50-100
Exit Fluid					Clean
properties					Nano fibre
					Micro fibre
					Macro fibre
					MM size fibre
					Protein Lignin
					BioChemical
					Sand/Earth
					derivatives
					Agro Crop/
					other Cellulse/
					Ligno
					cellulose fibre
					transportable
					chemicals
Fibre path &		Fibre internal	Fibre internal	Fibre internal	Material	Fibre external	Fibre external	Fibre external
properties		and external	and external	and external	transport	modification	modification	modification
		modification	modification	modification	through to	Level 1	Level 2	Level 3
		Level 1	Level 2	Level 3	back pressure
					zone
					Returned fibre
					bound/surface
					water +
					Pumped water
Component/s	Bearing-	Bearing-	Bearing-	Bearing-	Transport	Bearing-	Bearing-	Bearing-
Role	Stability	Stability	Stability	Stability	Ease of	Stability	Stability	Stability
	Transport/	Open	Open	Open	material
	Open Vertical	Transport-	Transport-	Transport-	forward flow +	Fibre	Fibre	Fibre
	Mass forward	Relaxation-	Relaxation-	Relaxation-	allow back	Engineering-	Engineering-	Engineering-
	transport of	water	water	water	pressured	Contact	Contact	Contact
	gravity/force	absorption	absorption	absorption	extract to exit	Modification	Modification	Modification
	fed Fibre/	Transport-	Transport-	Transport-		Standard	Standard	Standard
	Materials into	Forwarding/	Forwarding/	Forwarding/		Transport-	Transport-	Transport-
	first main	Pressure	Pressure	Pressure		Fibre forward	Fibre forward	Fibre forward
	extruder	building	building	building		movement	movement	movement
	housings	Flow	Flow	Flow		Modified	Modified	Modified
		inhibitors-	inhibitors-	inhibitors-		Transport-	Transport-	Transport-
		Dam effect +	Dam effect +	Dam effect +		Fibre dwell	Fibre dwell	Fibre dwell
		fibre opening +	fibre opening +	fibre opening +		time	time	time
		fibre to fibre	fibre to fibre	fibre to fibre		prolongation	prolongation	prolongation
		modification	modification	modification
Degassing					0-1
(Litres per					1-10
minute)					10-50
					50-100
Zone dwell	0-1	0-1	0-1	0-1	0-1	0-1	0-1	0-1
time-	1-2	1-2	1-2	1-2	1-2	1-2	1-2	1-2
(Minutes)	2-5	2-5	2-5	2-5	2-5	2-5	2-5	2-5
Relative to		5-10	5-10	5-10		5-10	5-10	5-10
screw RPM		10-30	10-30	10-30		10-30	10-30	10-30