RU2372433C2 - Disc refiner (versions), two refining elements for disc refiner (versions), combined plate of disc refiner and method of thermal mechanic refining of arboreal refuse wood - Google Patents

Abstract

FIELD: textile, cotton.

SUBSTANCE: intended to be used in pulp and paper industry. Offers the plate-shaped elements, the construction of plates and related thereto the installation for the thermal mechanic refining of the arboreal refuse wood where the grinded and partly grained refuse wood is delivered to the first refiner with rolling discs where each of the opposite discs has the knife and groove tracery of the internal wheel and knife and groove tracery of the peripheral wheel. Essentially, the refuse wood reaches its full grained condition within internal wheel and the grain is fibrillated within peripheral wheel. One version of the realisation are two opposite interacting refining element as the plates for refiner with flat discs where the knives and grooves of each of the internal wheels form the internal area of delivery whereafter there is a peripheral operation area. Knives and grooves of each of the peripheral wheels form the internal area of delivery whereafter there is a peripheral operation area, and the gap and/or space for the material flow passage formed during the installation of the plates one after another increases between internal operation area and peripheral operation area.

EFFECT: provides high-quality thermal mechanic arboreal mass at the low energy consumption.

46 cl, 32 dwg, 12 tbl

Description

The present invention relates to a method for manufacturing thermomechanical pulp from lignocellulosic raw materials, in particular from wood chips, and to equipment for its implementation.

Over the past decades, the quality of mechanical pulp obtained by thermomechanical pulping (TMVC) has been increased, but the increasing cost of energy used in these energy-intensive technologies leads to the need for efficient use of electricity while maintaining product quality. The principle underlying the further development of recent improvements in the direction of energy efficient use while maintaining quality is to determine the differences and to perform operations on special equipment such as axial separation of fiber and fiberization of wood chips other than fiber fibrillation for wood masses. The first steps mentioned are performed on the equipment intended for this, located upstream of the refiner, characterized by low energy consumption, which is consistent with the relatively low degree of processing and separation of the fiber, while the refiner, characterized by high energy consumption, is exempted from the energy-ineffective defibrization process , and this allows more efficient use of energy, directing it entirely to perform the function of fibrillation. This is necessary, since the fibrillation process requires even greater energy costs than the process of saponification of wood (also known as defibrization).

These improvements have indeed improved energy efficiency, especially in equipment where high-speed discs are used. However, with particular regard to equipment that did not use high-speed refiners, the long-term energy efficiency was somewhat obscured by the short-term need for more expensive or occupying large production facilities equipment located upstream of the primary refiner.

The objective of the invention is to create the design of a refiner plate, through which it is possible to produce high-quality thermomechanical pulp (TMDM) with lower energy consumption.

Basically, with the help of the invention, a significant increase in energy efficiency is achieved even where a high-speed refiner is not used in the equipment, since it reduces the volume and complexity of the necessary equipment located upstream of the refiner.

This problem is solved by creating devices according to paragraphs 1-44 of the claims and the method according to paragraphs 45-46 of the claims.

In a broad sense, the invention is directed to the creation of elements in the form of plates, the design of the plate and the corresponding installation for the thermomechanical refining of wood chips, in which the crushed and partially fiberized chips are fed into a primary refiner with rotating disks and in which each of the opposing disks contains a pattern of knives and grooves of the inner rings and the pattern of knives and grooves of the peripheral ring, and their design is such that by means of this they achieve substantially complete disintegration (defibration) of the chips in the inner ring, and the resulting fiber is fibrillated in the peripheral ring.

One embodiment is directed to the creation of a pair of opposing interacting refining elements in the form of plates intended for a refiner with flat disks for grinding and refining lignocellulosic material in a refining gap between two opposing refining disks rotating relative to each other, while the elements in the form of plates are intended to be arranged directly one before the other on opposing discs, the improvement being that both elements in the form of plates in complete with an inner ring including knives and grooves, and a peripheral ring including knives and grooves, the knives and grooves of each of the inner rings forming an inner supply region, followed by a peripheral working region, the knives and grooves of each of the peripheral rings forming an inner region supply, followed by a peripheral working area, and the gap and / or space for material flow, formed when the plates are installed in front of each other, increase between the inner working area and the periphery area of delivery.

Preferably, the working region of the inner ring is formed by a first pattern of alternating knives and grooves, and the feed region of the peripheral ring is formed by a second pattern of alternating knives and grooves. The first drawing of the working area of the inner ring contains relatively narrower grooves than the grooves of the second drawing of the peripheral ring supply region so that a gap is created in the geometry. Chipping is substantially completed in the working region of the inner ring by low-intensity refining; whereas fiber fibrillation is performed in the working region of the peripheral ring with a smaller gap between the plates and by means of a higher refining intensity.

The associated method preferably comprises the following steps: holding the chips in a steam environment to soften the chips; crushing by compression and dehydration of softened chips to a concentration greater than about 55%; dilution of crushed and dehydrated chips to a concentration in the range of about 30-55%; feeding the diluted crushed wood chips to a rotary disc refiner in which each of the opposing discs has a pattern of knives and grooves of the inner ring and a pattern of knives and grooves of the peripheral ring; chip dispersion (defibration) in the inner ring zone and fibrillation of the obtained fiber in the peripheral ring zone.

Compression grinding, dehydration and dilution can be carried out in one integrated equipment facility located directly upstream from the primary refiner, while the fiber is pulled and fibrillated with only one set of disks rotating relative to each other in the primary refiner.

It was shown that the use of a new simplified method of refining thermomechanical wood pulp, which combines the use of a grinding screw unloader with a support and fiberizing boards, can effectively improve the quality of thermomechanical wood pulp with comparable energy consumption in comparison with conventional methods of manufacturing thermomechanical wood pulp. Application of the method allows to improve the ratio: properties of wood pulp / energy consumption, at least when using the installation for the manufacture of thermomechanical wood pulp and the refining plant for the manufacture of thermomechanical wood pulp, which provide a short retention time at high pressure. Plants that provide short retention times at high pressures typically operate at overpressures in the range of 75-95 psi, either at standard or higher speeds of the refiner disk.

The defibration efficiency carried out by means of the inner ring increases at a higher pressure during refining. The degree of defibration increases further with increasing rotation speed of the refiner disk.

Thermomechanical pulp obtained using retaining peripheral rings has higher overall strength properties compared to pulp obtained using displacing peripheral rings. When using the latter configuration, less energy was required to achieve a given cage (degree of grinding) and to provide a lower content of fiber bundles.

The specific energy saving while ensuring the desired creep and when using the method proposed according to the invention in combination with the use of extruding peripheral rings was 15-32% in comparison with the control experiments on the production of thermomechanical pulp and experiments on the installation, which provide a short retention time at a higher pressure.

In most cases, the knives and grooves in the working area of the peripheral rings (in the fibrillation zone) should be smaller than in the working area of the inner rings (in the defibration zone). To make a mechanical pulp, the fiber must first be defibrated (i.e. separated from the wood structure) and then fibrillated (i.e. the fiber wall material must be separated). A key feature of this invention is that in the working area of the inner rings, defibration is mainly performed, and in the working area of the peripheral rings, fibrillation is mainly performed. An essential aspect of the novelty of the invention is to maximize the separation of these two processes in one machine and thereby achieve more efficient optimization of fiber length and pulp properties with efficient use of energy. Since defibration in the area of the inner rings is carried out by processing relatively coarsely ground chips, the pattern of knives and grooves in the associated working area cannot be very small. Otherwise, the crushed chips will not properly pass through the grooves of the inner rings and will not be distributed evenly. The defibrated material entering the peripheral ring supply region from the inner ring and distributed over the working region of the peripheral ring is relatively smaller than that which is in the inner supply ring and therefore the pattern of knives and grooves of the peripheral ring working region may be smaller than in the inner ring. Another advantage of the invention is that there is a more uniform distribution of the material (i.e., a more complete coating of the refiner plates with the fiber) both in the inner rings and in the peripheral rings as compared to conventional processes. Improved feed means greater feed stability, which helps reduce fluctuations when loading the refiner, which in turn helps to maintain a more uniform quality of the wood pulp.

For compatibility with conventional thermomechanical pulp plants, the combination boards of the present invention can be modified to allow steam to flow back despite a denser clearance in the working area of the inner board. Basically, at least one of the opposing plates may contain a channel for the return flow of steam for directing a certain amount of steam from the peripheral gap into the internal gap at the inner supply area or for supplying it even higher during the process, while bypassing the inner clearance at the inner work area.

An important advantage of the present invention is to minimize retention time at each functional stage of the entire process for producing thermomechanical pulp. This was possible because the particle size of the fibrous material was significantly reduced at each stage of the process so that at operating pressures the fiber can be heated and softened almost instantly to the desired level. The method can be considered as a process that includes three functional stages: (1) preparation of crushed chips; (2) defibration of crushed wood chips; and (3) fibrillating the defibrified material. The design of the equipment should be such as to ensure minimum retention time in the area from unloading from the soaking screw unloader with back-up in step (1) to the refiner inlet. The refiner feed device (for example, a tape feed device or a lateral feed device) acts almost instantly, providing the start of step (2) in the inner rings. The design of the inner rings should be such as to provide a retention time of the material at which it would pass without delay. The design of some inner rings may contain longer than others sections for effective defibration, but the net retention time is still less than if the release was carried out in a separate component. The defibrated material passes almost instantly to the peripheral ring where step (3) is performed. Here, the retention time is also small. The actual retention time in the peripheral ring is determined by the design of the slabs selected for reasons of optimizing pulp properties and energy consumption. The advantage of this very small retention (minimum) at each stage of the process (when the necessary softening of the fiber is achieved to maintain the strength properties of the wood pulp) is to ensure maximum optical properties. A key feature of these plates is that they contain an inner ring for defibration, and a peripheral ring for fibrillation, and a gap region between the rings, whereby a relaxation region is formed.

In the apparatus described in International Patent Application PCT / US2003 / 022057, in which the crushed wood chips were defibrated in a smaller fiberizing refiner before feeding the material into the primary primary fibrillator refiner, the pressures were much lower during the fiberizing (defibration) step. The retention time during pressure cracking was significantly longer in a completely separate refiner. It was desirable to maintain a lower temperature in order to maintain the brightness of the pulp, since the low refining intensity was weak. For this reason, high temperatures were not both necessary and desirable in a separate fiberizing refiner to maintain the strength of the wood pulp. In the present invention, fibrillation and fibrillation are performed in the same refiner housing under pressure. The refining intensity in the zone of dispersion (defibration) of the inner ring still remains low, and it is achieved at high pressure and short retention time. There is no negative effect on the brightness level despite the high pressure (temperature) due to such a short retention time. This phenomenon is similar to the effect of short retention time during preheating at high temperature, described in US patent No. 5776305.

When the present invention is carried out on a plant that provides short retention time and high pressure during refining, there is no need for a separate conveyor with preheating directly upstream of the refiner feed device, since the crushed chips quickly heat up during normal transport from the plug-damped auger unloader to the refiner. The excess ambient pressure in the area from the volume or expansion chamber to the rotating discs is equal to the excess working pressure in the refiner, for example 75-95 psi, and the "retention time" at the appropriate impregnation temperature during transportation in the area between the plug-damped screw auger unloader and the refiner is substantially less than 10 seconds, preferably within 2-5 seconds, which corresponds to the preferred retention time during pre-heating during refining using the installation, in which they provide short retention time and high pressure.

In a more general form, the advantage of the method in achieving the efficient use of energy in the production of high-quality thermomechanical pulp with minimum time periods at each stage of the method can be achieved in a wide range of refining plants and includes the additional advantage of minimizing the required components, production space and cost equipment for implementing the method. According to one aspect of the invention, double-ring geometry with a rupture region of refiner plates can be used in various types of flat plate plants without limitation, but vice versa, including refiners with unidirectional flat discs rotating in opposite directions and two-in-one refiners, and double disc refiners.

Figure 1 is a schematic view of a refiner installation for the production of thermomechanical pulp according to the present invention;

2A and 2B are schematic alternative embodiments of a soaking screw auger unloader with back-up with diluent feed means for use in the present invention;

FIG. 3 is a schematic view of a portion of a plate of a refiner disk, showing an inner fiberizing ring and a separate peripheral fibrillating ring; FIG.

Figa and 4B is a view of a pair of examples of internal razvonochnyh rings for the rotor and stator, respectively, containing inclined knives and grooves;

Figure 5 - the relative position of the pair of inner razvolokanie rings and a pair of peripheral fibrillating rings in the transition area;

6A and 6B are a view of another example of a pair of fiberizing rings containing substantially radially spaced knives and grooves;

Figa and 7B is a view of an example of a peripheral fibrillating ring (front and side views, respectively);

Figs, 7D and 7E are sections of knives and grooves in the peripheral, middle and inner zones, respectively;

Figa, 8B and 8C is a view of another example of a peripheral fibrillating ring (front view and sections, respectively);

Fig. 8D is a view of an example of a peripheral ring for a rotor disk containing curved feed knives (side and front views, respectively);

Fig. 8E is a view of an example of an opposing peripheral ring for a stator (side and front views, respectively) that is used with the peripheral ring shown in Fig. 8D;

Figure 9 is a schematic view of a slab that was used in laboratory studies to model and measure the performance of an internal fiberizing slab;

Figure 10 is a schematic view of a plate that was used in laboratory studies to model and measure the performance of a peripheral fibrillating plate;

11-18 are diagrams illustrating indicators of the properties of wood pulp obtained by performing various series of experiments in this study;

Fig. 19 is a view of an inner pair of rings for the rotor and stator, comprising a passage in the inner ring for the stator to direct the return flow of steam generated during refining;

Fig.20 is a view similar to that shown in Fig.19, which shows another variant embodiment of the direction of the return flow of steam through a channel in the disk carrying the inner ring for the stator;

Fig.21 is a view similar to that shown in Fig.19, which shows another variant embodiment of the direction of the return flow of steam through grooves on the surface of the working area of the inner ring;

Fig. 22 is a view similar to that shown in Fig. 4B, with the addition of grooves for reversing the flow of steam on the front side of the working area of the inner ring according to the embodiment shown in Fig. 21.

1 shows a refiner installation 10 for the production of thermomechanical pulp according to a preferred embodiment of the invention. In a standard plug-damped screw feeder 12, under atmospheric conditions, pre-steamed (softened) wood chips are supplied from source S at excess atmospheric pressure P ₁ = 0 and the pre-steamed wood chips are transported at excess pressure P ₂ = 0 to the steam pipe 14, where the chips are exposed saturated steam at a pressure of P ₃ . Depending on the design of the installation, the overpressure P ₃ can be in the range of atmospheric to about 15 psi or in the range of about 15-25 psi for retention times ranging from a few seconds to several minutes. The chips are fed into a screw discharger 16 soaking damped by a stopper 16 with a backwater.

The screw-stopping soaking-damped screw unloader 16 with a back-up contains an inlet part 18, which is under an overpressure P ₄ in the range of 5-25 psi for receiving steamed wood chips. Preferably, the overpressure at the inlet P _{4 of the} soaking screw unloader with back-up is the same as the pressure P ₃ in the steam pipe 14. The soaking screw unloader with back-up contains a working compartment 20 in which the chips are dehydrated and soaked under the influence of large mechanical compressing forces in a saturated steam medium, and an outlet part 22, where the soaked, dehydrated and pressed wood chips are discharged in the form of aged wood chips into the region or expansion chamber at a pressure P ₅ in which the aged wood chips expands. In the discharge part of the screw device there are nozzles or similar means for feeding the impregnating liquid and dilution water, where the dilution water penetrates into the expanding chips and together with the chips in the supply pipe 24 forms material for feeding into the refiner with a solid concentration in the range of about 30 -55%. In an alternative embodiment, especially in cases where impregnation is not required, but only dilution, the dilution can be carried out in the dilution chamber connected to the soaking screw unloader, but not necessarily made in one piece with it. In this context, soaking or grinding wood chips means that the axial separation of the fiber exceeds about 20%, but there is no fibrillation.

The primary refiner 26 for processing a high concentration of mass contains disks rotating relative to each other, in a housing 28 in which pressure P _{5 is} maintained, with a working plate on each disk, and the working plates located in opposite coaxial positions, thereby forming a space passing substantially radially outward from the inner edge of the disks to the peripheral edge of the disks. Each plate contains in radial direction an inner ring and a peripheral ring, with each ring having a pattern of alternating protrusions and grooves. The inner ring pattern contains protrusions and grooves of a relatively larger size, and the peripheral ring pattern contains protrusions and grooves of a relatively smaller size. Using the refiner feeding device 30, for example a tape feeding device, the feed material is received from the dilution zone associated with the soaking screw unloader with back-up (directly or via an intermediate reserve container), and the material is fed under pressure P ₅ into the space between the disks essentially at the inner the edges of the discs. As described in more detail below, with the help of the inner ring, the dispersion (defibration) of the chip material is completed, and fiber is fibrillated using the peripheral ring.

The installation can be integrated in a conventional installation for the production of thermomechanical pulp or in an installation in which they provide a short retention time at high pressure. This range of conditions for the implementation of the method or operation of the components can be presented in the form of the following Table:

Table
The range of operating conditions of the installation in accordance with the scope of the invention Component Conditions Range Preferred range Overpressure P1 (chip source S), psi 0 0 Pressure P2 (at the outlet of the plug-damped screw feeder 12), psi 0-30 0-30 Overpressure P2 (in the steam pipe 14), psi 0-30 0-30 Retention time in the steam pipe 14, sec 10-180 10-40 Overpressure P4 (at the inlet of the soaking auger unloader 16 with back pressure), psi 0-30 0-30 Processing time in a soaking auger unloader 16 with backup, sec <15 <15 Overpressure P5 (in expansion chamber 22, refiner feeder 30 and housing 28), psi 30-95 75-95 Swelling time in expansion chamber 22, refiner feeding device 30 and housing 28, sec <10 <10

FIGS. 2A and 2B schematically illustrate a soaking auger discharger 16 with a support with a diluent injection device suitable for use in the present invention. According to the embodiment of FIG. 2A, wood chips 32 are shown in the central dewatering portion of the working compartment 20, where the diameters of the perforated tubular wall 34, the rotated coaxial shaft 36 and the turns of the screw 38 are constant. A plug 40 of wood chips is formed in the part for forming a plug in the working compartment, immediately following the part in which dehydration is carried out, where the wall is not perforated and the screw shaft does not contain turns, but the shaft diameter increases significantly, resulting in a narrowed cross-section of the passage for flow and, thus, high back pressure, due to which the process of squeezing the liquid out of the chips through the drainage holes made in the wall of the central part is improved. The flow restriction and the soaking effect can be further enhanced or adjusted by using a tubular restriction insert (not shown) inserted into the non-perforated wall, or rigid rods or similar means (not shown) protruding from the wall into the compressed material in the cork. The cork is tightly compressed by mechanical pressure, usually

constituting 1000-3000 psi or more. Most, if not all, soaking occurs in a cork. The chips are substantially completely milled and partially defibrated, with the proportion of defibrated fiber exceeding about 20%, usually reaching 30% or more.

At the end of the plug, the discharge portion of the soaking screw auger unloader has a larger cross-sectional area formed between the outwardly expanding wall 42 and the opposing conical surface 44 of the drain valve 46. The position of the drain valve 46 can be axially adjusted from a closed position sealed in a conical recess 48 at the end of the shaft 36 of the soaking auger unloader with support to the maximum open position. In this way, it is possible to adjust the flow cross-sectional area in zone 50 or the expansion volume, while maintaining a soft seal in zone 52 by means of chip material between the valve opposing the outer edge of the expanding wall, which can be adjusted in response to the pressure transient between the nozzle 24 for feeding and soaking auger unloader 16 with a backup.

High pressure impregnating liquid is supplied to expansion zone 50 either through a plurality of pressure hoses 54 and nozzles connected to them (as shown in the drawing), or by means of a circular ring under pressure. Dehydrated wood entering the expansion zone 50 quickly absorbs the impregnating liquid and expands, contributing to the formation of a weakly compacted zone at the end of the expansion zone.

FIG. 2B shows an alternative embodiment in which impregnation in the expansion zone 50 is provided by making fluid flow openings 56 in the face of the conical drain valve and in which liquid can be supplied through pressure hoses through the drain valve shaft 58.

The supply pipe 24 is preferably a vertical gravity-acting pipe designed to guide and mix the diluted chips from the soaking screw unloader 16 with support to the refiner supply device 30. However, it should be borne in mind that the pressure P ₅ in the supply pipe 24 is the same pressure as in the supply device 30 and in the refiner housing 28. A slight rise or drop in pressure may be desirable between the refiner feeder 30 and the refiner housing 28, which is usually observed in practice in the manufacture of thermomechanical pulp, despite the fact that overpressure in this entire area after the soaking auger unloader with support to the refiner body is usually significantly exceeds 30 psi, usually above 45 psi, which is much higher than the steam pressure P ₄ at the inlet of the soaking auger unloader with back-up. However, the plug 40 is so mechanically compressed that even with an overpressure in the nozzle reaching 95 psi or more, the compressed plug expands rapidly in the expansion zone due to the expansion of pores in the fibers in an uncompressed state. Therefore, it can be considered that the supply pipe can function as an expansion chamber and contribute to the efficiency of the expansion volume. Specialists in this field can easily change the design and relationships of the expansion zone and the supply pipe so that expansion and dilution take place mainly in the expansion chamber intended for this, connected to the soaking screw unloader with a back-up, but not completed in one piece.

As an example, but not limitation, the concentration in the zone of the tube for the formation of cork is usually in the range of 58-65%, and in the expansion zone with impregnation and dilution means in the range of about 30-55%. In addition, the goal is to achieve the optimal concentration for refining, usually in the range of about 35-55%, when fed into the feed device for input between the plates of the refiner.

Figure 3 schematically shows parts of a refiner disk plate 100, which shows the inner fiberizing ring 102 and the peripheral fibrillating ring 104. Each ring can be a separate plate element attached to the disk, or the rings can be made integrally on a common basis, attached to the disk. Each ring contains an inner feeding region 106, 108 and a peripheral working region 110, 112. The working (defibration) region of the inner ring is formed by the first pattern of alternating knives 114 and grooves 116, and the peripheral ring supply region is formed by a second pattern of alternating knives 118 and grooves 120. C By means of very large knives 122 and grooves 124, pre-shredded wood chips are directed into the defibration region 110 of significantly narrower knives and grooves in the inner ring feeding region 106. The fiberized material is then mixed and traverses the transition annular space 126, where it extends into the peripheral ring feed region 108. Basically, the first pattern of the inner ring work area 110 comprises relatively narrower grooves than the grooves of the second pattern of the peripheral ring supply region 108. The working (fibrillating) area 112 of the peripheral ring has a pattern of knives 128 and grooves 130, in which the grooves 130 are already grooves 116 of the working area 110 of the inner ring.

Larger knives and grooves of the supply area 106 of the inner ring of one disk can be superimposed on the supply area of the opposite disk that does not contain knives and grooves, since the shape of the path of the feed stream is such that it makes it easy to direct the feed material from the tape feed device to the working area 110 of the opposite inner drives. Thus, each inner ring 102 has a peripheral fibrous region 110 with a pattern of alternating knives and grooves 114, 116, but the associated inner region 106 does not necessarily contain a pattern of knives and grooves. The peripheral region 112 of the fibrillating ring 104 may comprise a plurality of radially ordered zones, for example 132, 134, and / or a plurality of different but transverse regions, well known as “refining zones” in refiners for producing thermomechanical pulp, for example 136, 138 The peripheral ring 104 (see Figure 3) contains an inner area 108 of the supply of alternating knives and grooves, and the working area 112 contains the first pattern of alternating knives and grooves 128, 130, having the form of repeating in the transverse The direction trapezoids in zone 132, and another pattern of alternating bars and grooves 140, 142 having a repetitive form in the transverse direction trapezoids in zone 134, which extends to the outer edge of plate 144.

The annular space 126 between the inner and peripheral rings 102, 104 may be completely free or, as shown in FIG. 3, some of the knives, for example, the knives of the peripheral ring supply region 146, may extend into the annular space. The annular space 126 limits the dimensions of the inner and peripheral rings in the radial direction, and the width of the inner ring 102 in the radial direction is less than the width of the peripheral ring 104 in the radial direction, preferably less than about 35% of the total radius of the plate from the inner edge 148 of the inner ring 102 to the outer edge 144 the peripheral ring 104. In addition, the width of the feed region 106 of the inner ring 102 in the radial direction is greater than the width of the working region 110 of the inner ring in the radial direction while the width of the feed region 108 of the peripheral ring 104 in the radial direction is less than the width of the working region 112.

The crushed and partially pulverized wood chips are fed into the inner feeding region 106, where there is no significant additional pulping, and the material is fed into the working region 110, where essentially all the material is pulled by means of a low-intensity action of knives and grooves 114, 116, which are efficient in terms of energy utilization. Such slabs can be used as replaceable slabs in refiners, which may not contain a soaking unloader associated with them with back-up. If a soaking auger unloader with back-up is used, the combination of full grinding and partial raking, together with strong heating upstream of the refiner, allows the plate designer to minimize radial width and minimize energy use in the inner ring working area 110 to complete the raking process. The pattern of the knives and grooves 114, 116 and the width of the working area 110 can be changed to control the intensity and retention time. Even with a lower than ideal grinding level higher along the process and partially pulled, the slab designer can increase the width of the inner working zone 110 in the radial direction and choose a pattern that would allow the material to be held to some extent to ensure improved development, at the same time still achieving a satisfactory degree of fibrillation in the reduced high-intensity peripheral ring 112 and overall energy savings to obtain the desired quality of the primary woody ma pisses.

The combination plate shown in FIG. 3 is just one example of its embodiment. 4 and 6 show other possible variants of the areas of the inner rings. Figure 4A shows one inner ring 150A, and Figure 4B shows the opposite inner ring 150B. Figure 5 schematically shows the relative position of the opposing inner rings 150A and 150B with parts of the peripheral rings 152A and 152B associated with them as they are installed in the refiner. The feed gap 154 between the inner rings is preferably curved to change the direction of the feed material entering the disk aperture from the axial conveying direction to the radial direction of the working gap 156 between the inner rings. Preferably, the feeder knives (very large knives) are separated from each other at a distance greater than the size of the material in the feed mass. For example, the smallest of the three sizes determining the size of the chips (chip thickness) is usually 3-5 mm. This condition is chosen in order to exclude a hard blow, as a result of which fiber damage in the wood matrix would occur. In most examples, the minimum clearance 154 during operation should be 5 mm. The only function of larger feeder knives is to provide the peripheral part of the inner ring with an adequate distribution of the supplied mass, and they should not have a processing effect on the chips. The knives of the feeder are located on the inner ring of the rotor, and their presence on the inner ring of the stator is not necessary.

It should be borne in mind that the geometry of a conventional plate used in a flat disk refiner has a radius extending from the inner to the outer edges of the plate. Two flat plates form an opposing pair after they are installed in the refiner, each having a working face that includes a relief structure (for example, contains knives, grooves, recesses), which when viewed in the direction perpendicular to the axis, as shown in FIG. 5 form a radially extending refining gap between the plates. The gap has a profile that changes in the direction from the inner edge to the outer edge of the plates. The gap, as well as the gap profile, is limited by the size between the upper surfaces of the opposing protruding structures (knives) and directly affects the size of the area for the passage of the material flow when it is passed in the radial direction between the plates. In any position in the radial direction, the total area for the passage of flow includes the cross-sectional area of any recesses or grooves between the knives. The total change in the area of the passage for the flow, including the gap between the plates of ordinary flat disks, can be expressed as dA / dr <0 over the entire radial distance R _{i of the} inner edge to R _{0 of the} outer edge of the plate.

According to the present invention, the rate of change of the area for the passage of flow can be expressed by the following expressions:

dA / dr <0 on the segment from R _i to R _a ,

dA / dr> 0 on the segment from R _a to R _b ,

dA / dr <0 on the segment from R _b to R ₀ ,

where R _i <R _a <R _b <R ₀ .

The increase in area in the range between R _a and R _b can be understood as a gap or relaxation volume between or at the transition from internal to peripheral rings at the supply region of the peripheral ring. Material that has been defibrated in the working region of the inner ring enters the relaxation volume, where it is mixed and distributed under the influence of feed knives and grooves in the peripheral ring feed region.

The gap profile (see FIG. 5) comprises a conveying inner feed portion 154, followed by a gap 156 of the inner work area, preferably converging toward the inner minimum gap, which can extend radially in the form of a substantially constant gap. After converging by 10-30% at a distance of up to 1 inch, the gap in the working area reaches a minimum in the range of about 1.5-3.0 mm, and preferably about 2.0 mm. The width of the groove in this working area is less than about 4.0 mm, and preferably not more than about 3.0 mm. The orientation of the groove preferably contributes to forcing out the material as it unfolds. This is followed by an intermittent transition section 160, after which there is a sharp increase in the gap to a size exceeding 4.0 mm associated with the supply area of the peripheral ring. This gap can converge in the feed area, and after it comes the peripheral working section, which converges in the radial direction to the minimum peripheral fibrillating gap in the range of 0.5-1.0 mm. The gap has a radially straight middle line extending from the entrance to the inner work area to the output of the peripheral work area.

The inner clearance feed portion includes a large facial structure containing a large pattern of feed knives and grooves, while the inner work portion contains a relatively smaller razor-free pattern of knives and grooves. The transition section in which the effect of tearing or relaxation is achieved may include another large feeder pattern containing knives and grooves, while the peripheral working section contains a relatively smaller, fibrillating pattern of knives and grooves. In many embodiments, the grooves in the working area of the inner ring should be smaller than the grooves in the feed region of the outer ring. The grooves in the working area of the inner ring should be larger than the grooves in the working area of the peripheral ring. Basically, the intensity of the impact that the material experiences in the working area of the inner ring is less than the intensity that the material experiences in the working area of the peripheral ring.

It should be borne in mind that the area for the passage of flow increases in the transition zone and can be achieved by combining changes in the width of the gap and grooves. If the clearance increase is large, then the peripheral ring feed area is not necessarily larger than the working area of the inner ring. An increase in the area for flow passage for the relaxation of the material dA / dr> 0 occurs immediately after the minimum gap width of the fiberizing region (where area A is also minimal in the fiberizing region). An increase in the area of relaxation can be achieved by any one or more methods, including: (a) the implementation of opposite smooth annular recesses in both plates located radially between the inner and peripheral rings; (b) making a smooth annular recess in one plate and opposing large and / or beveled approaches of some knives of the peripheral feeder on the opposite plate (see Fig. 8D and E); (c) performing an annular configuration on each of the opposing plates and approaches of some knives of the peripheral feeder (see Figure 7); (d) not the execution of a ring configuration, but the execution of large feeder knives with or without bevels or small feeder knives with a feed bevel on all feeder knives.

In the embodiment shown in FIG. 4, the knives and grooves on the inner ring are arranged at an angle to the radius, thereby preventing the formation of a free-flow configuration in the inner ring and helping to increase the retention time if it is rotated to the left, or to accelerate the flow if it is rotated to the right. In the embodiment shown in FIG. 6, the inner rings 162A and 162B are essentially oriented in the radial direction, which does not enhance, but does not contribute to the suppression of centrifugal flows.

As shown in FIGS. 3 and 5, the knives at the inlet of the defibration region, for example, the peripheral region of the inner rings, contain a long bevel 164 or have a gradually descending wedge-shaped shape. Basically, the entrance to the fiberizing gap 156 between the inner rings is radially directed or close to the radial direction (there is no significant scatter in the transition). It also helps to prevent strong impacts on wood chips. The slope of the bevel should, as a rule, be a difference of 5 mm in height at a distance of 15-50 mm in the radial direction. The resulting slope is 1: 5-1: 10, but slopes of 1: 3-1: 15 with a height difference of 3-10 mm are also acceptable. With this shape of the wedge, there is a low intensity of “peeling” of wood chips, as opposed to a high intensity of impacts of conventional breaking knives operating with a small gap. The working gap 156 in the working area of the inner plate can be narrowed outwardly to a distance of 3 inches or more. If the bevel 164 is in shape in the lower range of the angle (for example, 1: 3), then a large taper gap 156 should be used, for example corresponding to a ratio of at least 1:40. This will make it easier to feed into a tighter gap. The peripheral part of the inner ring is preferably ground to a cone within about 2 ° depending on the application. The use of large cones and large working clearances reduces the amount of work performed by the inner rings. The design of the peripheral region of the inner ring should be such as to minimize impact on the feed material and maximize fiber length, while at the same time properly separating the fibers.

The width of the groove in the fiberizing region 110 should be less than wood particles, and preferably should approximately correspond to the minimum working clearance in the fiberizing region. Normally, no groove should be wider than 4 mm. This is ensured by the conditions under which the wood particles are more likely to be processed in the gap than are wedged between the knives and subjected to impacts of the knives of the opposite disc.

In the fibrous inner region 110, the chips are pulverized to fibers and bundles of fibers before they pass through the annular space 126 and enter the peripheral ring 104 at the transition section 160. This ring can strongly resemble the known design of a refiner plate for processing high-mass pulps. When the fibers are mostly separated, they are not subjected to high-intensity impacts. It is understood, when considering FIGS. 3 and 5, that if the raw chip could enter the peripheral ring feed area 108, then it would be subjected to high-impact shocks when it jammed between two large knives 118, 120. If the chip is correct split in the fibrous inner rings 102, then no large particles remain, so that they cannot be subjected to this type of exposure.

The inlet of the peripheral region of the inner ring contains a radial or near-radial junction (i.e., the arc has a substantially constant radius, as shown in front view). Large fluctuations in the radial direction of the beginning of the grinding surface usually lead to losses in the length of the fiber, if particles larger than the size of the gap are pumped into the gap at high speed. With a long bevel at the beginning of the region (the longer, the better), the particle sizes of the incoming material gradually decrease until they become small enough (size reduction) to pass into the gap formed by the working surfaces (not shown in Figure 5) . To increase the effectiveness of the action and / or increase the amount of energy used by the internal plates, partitions can be provided that are flush with the knives or below the level of the knives.

The separation of functions between the inner and peripheral rings can also be carried out using the so-called "conical disk", which contains a flat initial refining zone, followed by a conical refining zone in the same refiner. In this case, the fiberizing rings proposed according to the invention could be replaced by a flat refining zone, followed by conventional refining with a “main plate” in the conical part. Typically, the conical part in such refiners is performed with a cone angle of 30 ° or 45 °, for example, it is placed at an angle of 15 ° or 22.5 ° to the cylindrical surface. An example of such a conical disk refiner is described in US Pat. No. 4,283,016, issued August 11, 1981. Thus, the term "disk" in this context also means a "conical disk", and the term "substantially radially" includes, in general , the concept of "clearance in a conical refiner, directed outward, but made conical". The term "flat disk" is used in cases where the disk and / or plate are essentially flat over the entire working surface, as shown in the accompanying drawings.

Figures 7 and 8 show two embodiments of a peripheral fibrillating ring. These rings can be either high-intensity or very low-intensity. In order to illustrate the concept, FIG. 7 shows a ring whose pattern is a typical example of a high intensity peripheral ring 166 with one direction of knives and grooves. On Fig presents a bidirectional structure 182 with a very low intensity. Various other knife and groove configurations may be used, for example having a variable pitch (see, for example, US Pat. No. 5,893,525).

The unidirectional ring 166 has a larger pattern of knives and grooves and contains a front feed region 172, which reduces the retention time and energy absorption capacity in this area, forcing most of the energy to be spent in the peripheral part of the ring, which, in turn, increases the intensity of work performed here, and thus the ring can operate with a narrower gap. The working area of the peripheral ring contains two zones 168, 170, and in the outer zone 168 the grooves are narrower than in the previous zone 170. Some or all of the grooves, for example 176, in zone 168 may be through channels that are slightly inclined at an angle to the actual the radial direction of the ring, while other grooves, for example 180, in another zone 170 may contain partitions 174, 178, made flush with the knives or below the level of the knives. Basically, the peripheral disk 166 is similar to the peripheral disk 112 shown in FIG. 3.

In another example shown in FIG. 8, there is a figure 182 in which the grooves are directed substantially radially along the entire length with a variable pitch and which has no centrifugal feed angle. The feeding area 190 is very short, and in the working area 188 the grooves can be the same or variable width or, like grooves 184 and 186, alternating or variable depth. This design allows for a longer time to hold the processed material in the plates and, in combination with a large number of knife passages, allows for a low energy transfer rate, so that a larger gap between the plates can be set.

In an embodiment of the peripheral ring, the inner feed region of the peripheral ring is designed to prevent backflow of fiber from the peripheral ring into the inner ring. FIG. 8D shows a peripheral ring 192 for a rotor disk with a feed region 194 containing curved feed knives 195. The opposite stator ring 196 (see FIG. 8E) does not contain knives in the inner feed region 198 against rounded knives, and therefore, opposed curved feed knives 195 located on the peripheral ring 192 can be arranged in this region. This solution further provides complete separation stages of fibrillation and fibrillation in the inner and peripheral rings, respectively.

As shown in the drawings, the curved (injecting) feed knives 195 may optionally have a different design in the feed region of the rotor and / or stator ring (for example, they may be pyramidal and opposing radial knives) to facilitate the distribution of material coming from the curved knives in work area. Thus, the surface of the rotor feed region 194 in the radial direction can be fully or partially occupied by the protruding curved knives 195, and the surface of the stator feed region 198 in the radial direction can be a completely flat or partially occupied distribution structure. Curved knives 195 of the rotor ring protrude in the supply region 194 by an amount greater than the height of the knives in the working area, but due to the flat design of the opposing surface in the stator ring feed area 198, this large height can be accepted.

Basically, the pattern of knives and grooves over the entire working area of the inner ring has a first average, preferably uniform, density, and the pattern of knives and grooves over the entire supply area of the peripheral ring has a second average, preferably uniform, but lower density.

As shown by studies conducted in a pilot installation, on which the effective diameter of the primary refiner disk was 36 inches, the application of the invention made it possible to achieve significant advantages, which will be described in more detail below. The invention is particularly applicable to large-sized refiners in which disc diameters are in the range of about 45-60 inches or more.

The combination of fiberizing inner rings and highly efficient peripheral rings is thus an important component of the proposed method. The optimization of this method was carried out by using a single-disc refiner with Andritz model 36-1СР back-up in two stages, at first only internal plates were used, and at the second stage only peripheral plates were used. As internal plates, special three-zone refiner plates of the Durametal model D14B002 were used, in which half of the outer intermediate zone and the entire peripheral zone were sanded (see Fig. 9). The inner half of the intermediate zone was used to disperse shredded wood chips. As the peripheral plate used unidirectional refiner plate model 36604 of the company "Durametal" as for feeding (pushing), and to limit the flow (retention) during refining (see Figure 10).

Three configurations of refining devices were used, in which internal plates were installed to simulate the following process variants:

1. TMDMA (TMPA) [(i) retention time of 2-3 seconds; overpressure 85 psi (586 kPa); rotation speed 1800 min ^-1 ]; ii) A1 is indicated in the tables.

2. TMDMV (TMRV) [(i) retention time of 2-3 seconds; overpressure 85 psi (586 kPa); rotation speed 2300 min ^-1 ]; ii) A2 is indicated in the tables.

3. TMDM (TMP) [(i) the duration of retention of 2-3 seconds; overpressure 50 psi (344.7 kPa); rotation speed 1800 min ^-1 ]; iii) A3 is indicated in the tables.

i) Retention in the area from the screw unloader with support to the refiner inlet.

ii) Pressure in the steam pipe 5 psi, retention time 30 sec.

iii) Pressure in the steam pipe 20 psi, retention time 180 sec.

To represent the combination of grinding on a soaking auger unloader with back-up and fiberizing internal plates, the f - icon located in front of the unit designation was used. Thus, the nomenclature of equipment used to carry out the above processes was as follows:

1) f -TMPA

2) f- TMRV

3) f- TMP.

The fibrous material ( f ) was then refined using peripheral refining plates at similar corresponding pressure and rotational speed parameters of the refiner disk, i.e.

1) f -TMPA with peripheral plates: overpressure 85 psi, rotational speed 1800 min ^-1 ;

2) f- ТМРВ with peripheral plates: overpressure 85 psi, rotation speed 2300 min ^-1 ;

3) f- TMP with peripheral plates: overpressure 50 psi, rotational speed 1800 min ^-1 .

Most of the specific energy was expended during the operation of the peripheral refiner plates. The tests were carried out with different directions of rotation of the refiner plates (with pushing and holding) and the applied power was determined during operation of the peripheral plates.

Each primary refined pulp sample was then refined in an Andritz 401 secondary atmospheric refiner at three levels of applied specific energy.

Control samples of thermomechanical pulp were also produced without grinding wood chips in a soaking unloader with backwater. These control runs were carried out with reduced performance of the internal slabs from 24.1 metric tons of absolutely dry product (MTASP) to 9.4 MTASP. As a result of this, the blockage plug from the chips in the soaking screw unloader with back-up was effectively reduced. During control runs using internal plates, the plates were moved away so that the reduction in size was achieved only due to the action of the cutter knives, i.e. without an effective refining action with the help of raffiner knives in the wake after broken knives. After processing the internal chips, the chips were then refined in the refiner model 36-1СР using peripheral plates. The primary refined pulp was then refined in an Andritz 401 refiner at several levels of specific energy consumption.

Table A presents the nomenclature of equipment used in each of the refining options conducted in this study. Appropriate sample identification is also provided.

Table a Nomenclature * of equipment Sample Identification Primary processing using internal slabs Peripheral primary processing Secondary processing f-TMPA: 1800 min ^-1 ; retention slickness 485 ml A1 A4 A7, A8, A9 f-TMPA: 1800 min ^-1 ; pushing out; 663 ml A1 A5 A10, A11, A12 f-TMPA: 1800 min ^-1 ; pushing out; 661 ml A1 A6 A13, A14, A15 f-TMPA: 1800 min ^-1 ; pushing out; 460 ml A1 A16 A22, A23, A24 f-TMPA: 1800 min ^-1 ; pushing out; shortness of 640 ml; (2.8% NaHSO ₃ ) A1 A17 A25, A26, A27 f-TMPA: 1800 min ^-1 ; retention dryness 588 ml A1 A18 A28, A29, A30 f-TMPD: 2300 min ^-1 ; pushing out; 617 ml A2 A19 A31, A32, A33 f-TMPD: 2300 min ^-1 ; pushing out; sagasti 538 ml; (3.1% NaHSO ₃ ) A2 A20 A34, A35, A36 f-TMP: 1800 min ^-1 ; pushing out; slickness 597 ml A3 A21 A37, A38, A39 f-TMP: 1800 min ^-1 ; retention 524 ml A3 A41 A46, A47, A48 TMP: 1800 min ^-1 ; retention 664 ml A3-1 A44 A54, A55, A56, A57, A58 TMP **: 1800 min ^-1 ; retention creepiness 775 ml A3-1 A43 A49, A50, A51, A52, A53 * Nomenclature = process, speed of the primary refiner (1800 min ^-1 or 2300 min ^-1 ); peripheral plate configuration (push or hold mode), cage (degree of grinding) after primary refining.
** Poor results: the freeness after initial refining was too great.

In the series of tests performed on the refiner using primary peripheral plates in the holding mode, a larger gap was established between the plates and a higher content of long fibers was obtained than in the corresponding series performed using peripheral plates in the ejection mode. This made it possible to conduct a series of refining tests in the holding mode to lower levels of primary hardening while maintaining the content of long fibers in the wood pulp.

11-18 are diagrams of the properties of wood pulp obtained in most series of refining experiments performed in this study. Two series performed at very low primary creep (<500 ml) were excluded from the results array due to blockage.

11: diagram of the dependence of creep on the specific energy consumption.

When performing control experiments to obtain thermomechanical wood pulp, the highest specific energy consumption was observed to achieve a given hardening. When carrying out a series of experiments on the f- TMP installation, the following highest levels of specific energy consumption were observed, then the results obtained on the f- TMPA installation were followed. The series developed at the f- ТМРВ installation showed the lowest levels of specific energy consumption to achieve a given shortness.

Table B compares the specific energy consumption in each of the series of refining experiments with 150 ml sagacity. The results are obtained by linear interpolation.

Table B
Specific Energy Consumption at 150 ° C Specific energy consumption, kWh / metric ton (MT) f-TMPA: 1800 min ^-1 ; pushing out; 661 ml 1889 f-TMPA: 1800 min ^-1 ; retention dryness 588 ml 1975 f-TMPD: 2300 min ^-1 ; pushing out; 617 ml 1626 f-TMP: 1800 min ^-1 ; pushing out; slickness 597 ml 2060 f-TMP: 1800 min ^-1 ; retention 524 ml 2175 TMP: 1800 min ^-1 ; retention 664 ml 2411 f-TMPA: 1800 min ^-1 ; pushing out; shortness of 640 ml; (2.8% NaHSO ₃ ) 2111 * f-TMPD: 2300 min ^-1 ; pushing out; sagasti 538 ml; (3.1% NaHSO ₃ ) 1411 * * By extrapolation

When carrying out a series of experiments on the f- ТМРВ installation (2300 min ^-1 ; pushing out; a combination of dispersion, ТМРВ and high-intensity boards) there was a decrease in energy consumption by 32% compared to the control series for the production of thermomechanical wood pulp at 150 ml dryness. When the series of experiments on the f -TMRA (1800 min ^-1; retention) and f -TMRA (1800 min ^-1; eject) there was a decrease of energy consumption by 18% and 22% respectively in comparison with control series production of thermomechanical pulp with a creep of 150 ml. When carrying out a series of experiments on the f- TMP (retention) and f- TMP (ejection) installation, there was a decrease in energy consumption by 10% and 15%, respectively, in comparison with the control series of thermomechanical pulp production with 150 ml sagging. The results indicate that the reconstruction / replacement of a screw auger unloader and refiner slabs can lead to significant savings in capital investment in existing lines for the production of thermomechanical pulp.

12: a diagram of the dependence of the strength index on the specific energy consumption.

The wood pulp obtained at the f- ТМРВ installation (ejection) had the highest strength index for a given specific energy consumption, then the series obtained at the installation followed, then the series obtained at the f- ТМРА installation, and then the series obtained at installing f- tmp. Control samples of thermomechanical pulp had the lowest strength indices at a given specific energy consumption.

The addition of approximately 3% sodium hydrosulfite solution (NaHSO ₃ ) to the product discharged from the screw unloader with back-up led to an increase in the strength index compared to the corresponding series in which no chemical treatment was used.

A strength index of 52.5 Nm / g was achieved in the series developed at the f- ТМРВ installation (2300 min ^-1 ; ejection; 3.1% NaHSO ₃ ; 1754 kWh / metric ton of absolutely dry product (MTASP).

Fig: diagram of the dependence of the strength index on the sadness (chemical treatment was not performed).

Two groups of strength indices were observed. The lower group represents a series of experiments performed using ejector peripheral plates. The upper group represents a series of experiments performed using retaining peripheral plates. The average increase in strength index using holding plates was approximately 10%. It should be noted that in these studies, tests on the f- ТМРВ installation (retention) were not carried out due to the shortening of the fiber in the fibrous material A3.

The addition of an approximately 3% hydrosulfite solution in a series of experiments conducted on f- TMPA (ejection) and f- TMPV (ejection) plants increased the strength indices to the same or higher level as in the production of wood pulp with retention.

Table C compares the properties of refined wood pulp at 150 ml. The regression equations used in the interpolation are shown in FIG. 13.

Table C
Strength Index 150% Strength Index, Nm / g f-TMPA: 1800 min ^-1 ; pushing out; 661 ml 43.8 f-TMPA: 1800 min ^-1 ; retention dryness 588 ml 47.7 f-TMPD: 2300 min ^-1 ; pushing out; 617 ml 42,4 f-TMP: 1800 min ^-1 ; pushing out; slickness 597 ml 43.5 f-TMP: 1800 min ^-1 ; retention 524 ml 48.1 TMP: 1800 min ^-1 ; retention 664 ml 48,2 f-TMPA: 1800 min ^-1 ; pushing out; shortness of 640 ml; (2.8% NaHSO ₃ ) 47.0 * f-TMPD: 2300 min ^-1 ; pushing out; sagasti 538 ml; (3.1% NaHSO ₃ ) 47.9 * * By extrapolation

Fig: diagram of the dependence of the index of resistance to tear resistance from creep.

In a series of refining experiments performed using retaining peripheral plates, the highest tear resistance index and long fiber content were achieved.

Table D compares the tear resistance indices of materials obtained in a series of refining experiments at 150 ml sagacity. Tear resistance index values were obtained using linear interpolation.

Table D
Tear Resistance Index at 150% Tear resistance index, mN · m ² / g f-TMPA: 1800 min ^-1 ; pushing out; 661 ml 9.0 f-TMPA: 1800 min ^-1 ; retention dryness 588 ml 9.9 f-TMPD: 2300 min ^-1 ; pushing out; 617 ml 8.7 f-TMP: 1800 min ^-1 ; pushing out; slickness 597 ml 8.6 f-TMP: 1800 min ^-1 ; retention 524 ml 9.3 TMP: 1800 min ^-1 ; retention 664 ml 9.1 f-TMPA: 1800 min ^-1 ; pushing out; shortness of 640 ml; (2.8% NaHSO ₃ ) * 9.7 f-TMPD: 2300 min ^-1 ; pushing out; sagasti 538 ml; (3.1% NaHSO ₃ ) * 8.8 * By extrapolation

The wood pulp obtained on the installation f- TMPA (retention), had the highest value of the index of resistance to tear. The wood pulp obtained with the f- ТМРА (ejection) and f- ТМРВ (ejection) plants had comparable properties by the tear resistance index.

15: a diagram of the dependence of the index of resistance to breakthrough from flickering.

In a series of experiments conducted at facilities f -TMRA (1800 min ^-1; retention) and f -TMP (1800 min ^-1; retention) with a peripheral retaining plates, pulp had the highest index of resistance break at a given freeness. In a series of experiments carried out with the ejector plates at the peripheral installations f -TMRA (1800 min ^-1, ejection), f -TMP (1800 min ^-1; ejection) and f -TMRV (2300 min ^-1, ejection), woodpulp possessed lower breakout resistance indices for a given sadness.

The addition of approximately 3% hydrosulfite solution led to an increase in the index of resistance to breakthrough of wood pulp produced using push-out peripheral plates to the same level as in the series where chemical treatment developed using holding-off peripheral plates was not applied.

Table E compares the results of breakthrough resistance tests, interpolated relative to the freeness of 150 ml.

Table E
150 mL Breakthrough Resistance Index Breakthrough resistance index, kPa · m ² / g f-TMPA: 1800 min ^-1 ; pushing out; 661 ml 2,51 f-TMPA: 1800 min ^-1 ; retention dryness 588 ml 2.85 f-TMPD: 2300 min ^-1 ; pushing out; 617 ml 2,30 f-TMP: 1800 min ^-1 ; pushing out; slickness 597 ml 2,38 f-TMP: 1800 min ^-1 ; retention 524 ml 2.76 TMP: 1800 min ^-1 ; retention 664 ml 2.45 f-TMPA: 1800 min ^-1 ; pushing out; shortness of 640 ml; (2.8% NaHSO ₃ ) * 2.98 f-TMPD: 2300 min ^-1 ; pushing out; sagasti 538 ml; (3.1% NaHSO ₃ ) * 2.67 * By extrapolation

16: a diagram of the dependence of the content of bundles of fibers from sagasti.

Control samples of thermomechanical pulp had the highest levels of fiber bundles. Samples developed using ejector peripheral plates had lower fiber bundle levels than the corresponding samples developed using retention peripheral plates. It has been clearly shown that pre-treatment of type f helps to reduce the content of fiber bundles.

Table F compares the levels of fiber bundles in each series of refining samples interpolated to 150 ml sagacity.

Table F
Fiber bundle content at 150 ml creep The content of fiber bundles,% f-TMPA: 1800 min ^-1 ; pushing out; 661 ml 0.70 f-TMPA: 1800 min ^-1 ; retention dryness 588 ml 1.35 f-TMPD: 2300 min ^-1 ; pushing out; 617 ml 0.31 f-TMP: 1800 min ^-1 ; pushing out; slickness 597 ml 0.37 f-TMP: 1800 min ^-1 ; retention 524 ml 1,61 TMP: 1800 min ^-1 ; retention 664 ml 2.63 f-TMPA: 1800 min ^-1 ; pushing out; shortness of 640 ml; (2.8% NaHSO ₃ ) * 0.59 f-TMPD: 2300 min ^-1 ; pushing out; sagasti 538 ml; (3.1% NaHSO ₃ ) * 0.18 * By extrapolation

In a series of samples developed at the f- ТМРВ (pushing) plant with and without hydrosulfite, wood pulp had the lowest levels of fiber bundles. The addition of hydrosulfite led to a decrease in the content of fiber bundles.

17: diagram of the dependence of the coefficient of dispersion from the flicker.

In a series of specimens developed on a refiner using push-out peripheral plates, wood pulp had the highest levels of dispersion coefficient.

Table G shows the scatter coefficients for each series of samples at 150 ml sagacity.

Table g
The dependence of the spread coefficient on the freeness Spread coefficient, m ² / kg f-TMPA: 1800 min ^-1 ; pushing out; 661 ml 57.1 f-TMPA: 1800 min ^-1 ; retention dryness 588 ml 55.1 f-TMPD: 2300 min ^-1 ; pushing out; 617 ml 56.8 f-TMP: 1800 min ^-1 ; pushing out; slickness 597 ml 56.3 f-TMP: 1800 min ^-1 ; retention 524 ml 53.6 TMP: 1800 min ^-1 ; retention 664 ml 54,4 f-TMPA: 1800 min ^-1 ; pushing out; shortness of 640 ml; (2.8% NaHSO ₃ ) * 55.9 f-TMPD: 2300 min ^-1 ; pushing out; sagasti 538 ml; (3.1% NaHSO ₃ ) * 53.8 * By extrapolation

The addition of approximately 3% hydrosulfite solution resulted in a reduction in the spread coefficient by approximately 1-3 m ² / kg.

Fig: diagram of the dependence of the degree of whiteness on the creep.

In all series of experiments f, wood pulp had a higher degree of whiteness than control samples of thermomechanical wood pulp.

Table H compares the degree of brightness of the pulp in each series of samples interpolated relative to the freeness of 150 ml.

Table H
ISO brightness at 150 ml ISO brightness f-TMPA: 1800 min ^-1 ; pushing out; 661 ml 52.0 f-TMPA: 1800 min ^-1 ; retention dryness 588 ml 51.3 f-TMPD: 2300 min ^-1 ; pushing out; 617 ml 52.8 f-TMP: 1800 min ^-1 ; pushing out; slickness 597 ml 49.4 f-TMP: 1800 min ^-1 ; retention 524 ml 48.9 TMP: 1800 min ^-1 ; retention 664 ml 47.3 f-TMPA: 1800 min ^-1 ; pushing out; shortness of 640 ml; (2.8% NaHSO ₃ ) * 56.5 f-TMPD: 2300 min ^-1 ; pushing out; sagasti 538 ml; (3.1% NaHSO ₃ ) * 59.1 * By extrapolation

In a series of experiments conducted on the f- TMP unit, wood pulp had approximately 2% higher brightness than control samples of thermomechanical wood pulp. The higher degree of extraction of wood extracts, achieved by processing on a screw unloader with back-up with stronger compression during pre-treatment of type f , most likely contributed to the increase in brightness.

In a series of experiments conducted on the f- ТМРВ installation, wood pulp had the highest degree of whiteness (52.8), followed by samples developed on the f- ТМРА installation ( 51.7 on average), and then on f - TMP (average 49.2)

The addition of 3% hydrosulfite led to a significant increase in the degree of whiteness, up to 59.1 in the series of samples developed at the f- ТМРВ installation (ejection).

Table I compares the properties of the fibrous material after processing the internal plates. As mentioned above, three variants of fiberizing technologies were investigated: A1, A2, A3, to simulate the configurations of f- ТМРА, f- ТМРВ and f- ТMP. In each of these options, the crushed chips obtained after the screw unloader with support were passed through the inner rings.

Table I
The properties of the fibrous material after processing in the inner plates Material obtained at the fiberizing unit (f-) Process Pressure psi Performance, MTASP Specific energy consumption, kWh / MTASP The content of fiber bundles,% Sieve +28,% A1 TMPA 85 23.3 152 66.5 75,4 A2 Tmrv 85 23.3 122 35.6 79,4 A3 TMP fifty 24.1 243 88.7 82,4

Studies show that process conditions have a major impact on defibration efficiency during refining in the inner zone. Ground chips refined at a higher pressure (A1, A2) contain significantly fewer fiber bundles (which corresponds to a larger amount of defibrated fiber) compared to refining at a typical pressure (50 psi) with a thermomechanical method for producing wood pulp. The energy requirement for defibration was also lower at high pressure. The highest level of defibration was achieved when high pressure and high speed (A2) were combined.

Material A2 ( f- ТМРВ) had the highest fiber separation, followed by material A1 ( f- ТМРВ). Material A3 ( f- TMP) was clearly the coarsest of the fibrous samples.

It was noted that the orientation of the knives was not a significant factor in refining in the inner zone, since the inner plates were bidirectional.

The energy consumption for defibration decreased with increasing pressure. The energy loss was very significant when defibration was carried out under normal conditions. For example, to produce a fiber-coated material at an overpressure of 50 psi with the same fiber bundle content as for refining at an overpressure of 85 psi, an additional specific energy consumption would be significantly higher than 100 kW h / MTASP.

To produce these samples, wood chips from white Canadian spruce wood from a piece were used. Wisconsin. Material identification, solids content and bulk density of spruce wood chips are presented in Table II.

At first, several runs were carried out on a refiner model 36-1СР under pressure with variable speed, using a plate with a pattern of model D14В002, in which the peripheral zone and half of the intermediate zone were ground. This was done in order to simulate the inner rings of large single-plate refiners. The first version of material A1 was obtained with preliminary exposure in a steam medium for 30 seconds in a steam pipe at a pressure of 0.4 bar (the pressure in the refiner body was 5.87 bar); machine speed was 1800 min ^-1 . When developing material A2, the speed of the machine was increased to 2300 min ^-1 . The production of material A3 was carried out with preliminary exposure in a steam medium for 180 seconds in a steam pipe at a pressure of 1.38 bar (pressure in the refiner body was 3.45 bar); machine speed was 1800 min ^-1 . The production of material A3-1 was also carried out under conditions similar to the conditions for the production of material A3, except that the productivity was reduced from 24.1 MTASP to 9.4 MTASP in order to prevent crushing of wood chips before it is fed to the refiner. The gap between the slabs for this sample was also increased to exclude any effective effect from the intermediate zone of the knives, so that the chips were processed only with broken knives. Analysis of the quality of sample A1-1 was not possible, since wood chips treated only with cutting knives were not obtained in a loose form; therefore, it was not possible to conduct a fiber bundle analysis or a Bauer analysis.

Each of these materials (wood pulp) was used to generate additional series of samples. Six series were performed on material A1. Peripheral plates (Durametal model 36604) were installed in a Model 36-1CP refiner to simulate a peripheral refining zone. All six primary runs through the peripheral zone were performed on the 36-1СР model at a pressure in the refiner body of 5.87 bar and at a disk speed of 1800 min ^-1 . These passes were performed on a TMPA installation. Sodium hydrosulfite solution was added to material A17, performing a chemical reaction, in an amount of 2.8% NaHSO ₃ (calculated on absolutely dry wood substance). Three secondary runs through the refiner were performed using the material of each series.

Two series of runs were performed using material A2. Both runs through the peripheral zone of model 36-1СР, which were performed (A19 and A20), were carried out at a pressure in the refiner body of 5.87 bar and at a machine speed of 2300 min ^-1 . These runs were performed on an RTS installation. Sodium hydrosulfite solution (3.1% NaHSO ₃ ) was added to material A20. Again, three secondary runs through the refiner were performed using each batch material.

Several series of runs were also performed using A3 material, each at a pressure in the refiner body of 3.45 bar and at a machine speed of 1800 min ^-1 . Three secondary runs through the refiner were performed using the material of each series. These runs were performed on a TMP installation. Many of the runs on the Model 36-1CP secondary refiner were performed in the reverse mode shown in Table IV.

Two control series of TMP runs were performed (A43 and A44) using chips A3-1, which was subjected to processing only broken knives during refining in the inner zone. Both materials A43 and A44 were refined under pressure in a vapor medium of 3.45 bar and at a machine speed of 1800 min ^-1 . Then, several runs were carried out through the refiner under atmospheric conditions using these wood pulp samples to reduce creep to a comparable level, as in the previous series of experiments.

All samples of wood pulp were tested according to the TAPPI standard (Technical Association of the Paper Industry (USA)) and in accordance with the Andritz Inc. Business Regulations in cases where they were applicable. Tests included: determination of creep (grinding degree) on a Canadian device, determination of fiber bundle content according to the Pulmac standard (0.10 mm sieve); Bauer classification optical fiber length determination; determination of physical and optical properties. This information is shown in Table III.

As described above with reference to FIGS. 3, 4 and 5, the refiner plates were mounted coaxially in opposite positions, thereby defining a refiner clearance that extends substantially radially outward from the inner radius of the discs to the outer radius of the discs. The refiner clearance includes a peripheral gap 158 between opposing peripheral rings, for example 152A and 152B, and an inner clearance 156 between opposing inner rings, for example 150A and 150B. For perfect dispersion of the crushed chip material, the working area 110 of one inner ring should be close to the working area 110 of the opposite inner ring. This gap is in the range of 1.5-30 mm, and ideally is about 2 mm. However, the tight gap between the inner rings of the working area, which contains a sufficiently small pattern of knives and grooves to achieve the desired effect of razvolneniya, can block the movement of steam flow back to the tape device 30 feed and any pre-heater located upstream of the process (see Fig. .one). In some known plants for the production of thermomechanical pulp, the steam backflow generated during fibrillation is used to maintain the elevated pressure in the refiner pre-heater and belt feeder. According to the present invention, steam is generated in the peripheral gap 158 between the working areas 112 of the peripheral rings. For compatibility with known installations such as a thermomechanical pulp manufacturing plant, the combination boards of the present invention can be modified to allow steam to flow back despite a denser clearance in the working area of the inner board.

Basically, at least one of the opposing plates may contain a channel for the return flow of steam for directing a certain amount of steam from the peripheral gap to the internal gap at the inner supply region 154 or to a place located even further upstream, but at the same time bypassing internal clearance 156 near the internal work area.

One solution, shown in FIG. 19, is to open the back side 202 of the inner plates 204 on the stator 200, which allows the pair 210 to pass upstream into the channel 206 in the process direction, behind the inner ring workspace 208. This steam bypass will not adversely affect the retention time of the fiber in the inner rings (the retention time in the inner rings should be kept short in order to avoid too much fiber accumulation, which increases friction losses and, consequently, increases energy consumption). It is common practice to form each refiner plate from a plurality, for example of ten segments, or elements, of a disc, which (each) are bolted to the disc. According to the present invention, the inner ring may consist of a set of segments of the inner ring, and the peripheral ring may be made of another set of segments of the peripheral ring. Some or all segments of the inner ring may contain a through channel or groove 206 (in the inter-surface area with the disk) for passing steam bypassing the working area of the corresponding segment, with an input 212 located in the gap 126 of the refiner further in the radial direction from the working area of the inner ring.

As shown in FIG. 20, an embodiment comprises a passage 214 formed in the disk itself, preferably in the stator. This solution can be especially effective if the plate is formed of a separate inner ring and a separate peripheral ring attached to the disk so that an annular space 126 is formed between the rings. The input 212 into the bypass channels for steam can be located in the disk in this ring space. Such a steam path through the refiner disk may, in an alternative embodiment, be formed by providing one or a plurality of holes in the disk aligned with corresponding holes in the plates, somewhere in the radial direction outside the inner working area 208. The holes must be connected to the feed side of the refiner by the pipeline, and the supply can be made to one or more points located somewhere near the discharge zone of the screw feeder that is plugged by the plug (or the stuffing box to the feed system), and the input - near the middle in the radial direction of the refiner plates.

Another solution, shown in Fig.21 and 22, contains a channel 216 for steam, located at the surface of the working area 208 of the inner ring, preferably on the stator. This channel is formed for the sole purpose of allowing steam to pass back into the supply system instead of being trapped between the inner and peripheral rings. Such a channel for extraction is performed diagonally or obliquely directed relative to the pattern of knives and grooves in the working area of the inner ring either on the rotor or on the stator, or on both bevels 164 of the knives of the working area, or to the feed gap 154. The steam bypass has an inlet 218 near the annular space 126 between the inner and peripheral rings. The location of the channel on the stator provides the path of least resistance for the passage of steam. The rotor, even if there is a channel, would have a tendency to pump steam forward, and when the channel is executed in the stator, steam can pass in the opposite direction. As in the embodiment described above, steam can be directed from the radially outer end in the working region 208, which is usually located in the space between the inner and peripheral rings, by means of a surface bypass channel. The grooves are made in a direction opposite to the direction of rotation, so that the feed material is not pumped into the grooves of the stator inner ring, allowing untreated chips to pass through these grooves. In the embodiment shown in the drawings, the angle of the grooves is selected so that all incoming wood chips are forced to pass through the refiner gap and reach the peripheral refining region. The side bypass channel 216 for steam in a side view is simply a groove in the plate pattern, passing at an angle of about 20-30 ° to the horizontal direction to the knives directed to the outer edge of the ring, and with a minimum inclination to the knives protruding to the inner edge (diameter) . This geometry contributes to the forced movement of wood chips back into the gap under the influence of mechanical forces when material enters these grooves for the removal of steam. The grooves for the vapor may be deeper than the surrounding pattern (in this case, they have the same depth), and the channel may be straight (as in this case) or curved.

Although experiments have been conducted in the past using grooves for steam of various shapes and even grooves passing through the backside of segments, they have been designed to facilitate the passage of steam forward rather than backward. The author does not know the work on the modification of refiner plates to increase the steam back flow, i.e. in the opposite direction, upstream of the process.

Claims (46)

1. Disk refiner for refining wood chips, containing flat rotating disks relative to each other, each of which contains a working plate mounted on it, and the working plates are mounted coaxially one opposite the other so that between them was formed a gap of the refiner, passing essentially radially direction from the inner edge of the disks to the outer edge of the disks and forming a space for the flow of chips to be refined, characterized in that each plate contains an inner radially and a fibrous ring and a radially peripheral fibrillating ring, each ring containing an inner feed region and a peripheral work region, wherein the inner ring work region is formed by a first pattern of alternating knives and grooves, and the peripheral ring feed region is formed by a second pattern of alternating knives and grooves, wherein said flow space increases directly from the inner work area to the peripheral feed area. 2. The refiner according to claim 1, characterized in that the refiner gap comprises a peripheral gap formed by opposing peripheral rings and an internal gap formed by opposing inner rings, wherein
a refiner is a refiner for producing thermomechanical pulp, in the peripheral gap of which steam is generated between the working areas of the peripheral rings; and
at least one of the opposite plates contains a channel for the return flow of steam for directing a certain amount of the said steam from the peripheral gap to the internal gap near the inner supply region or higher in the process, bypassing the inner gap at the inner working region. 3. The refiner according to claim 2, characterized in that the channel for the return steam stream contains a passage through the stove, the outlet of which is below the inner working area of the stove. 4. The refiner according to claim 2, characterized in that one of the plates is installed on the stator disk, and the channel for the reverse flow contains a passage through the stator disk. 5. The refiner according to claim 2, characterized in that the channel for the return steam stream is made in the form of a groove extending over the surface of the working area of the inner ring and diagonally directed relative to the knives and grooves of the above-mentioned pattern of knives and grooves. 6. The refiner according to claim 2, characterized in that it contains an annular space between the inner ring and the peripheral ring. 7. The refiner according to claim 6, characterized in that the channel for the return steam stream has an inlet located near the annular space between the inner and peripheral rings. 8. The refiner according to claim 1, characterized in that the inner and peripheral rings are separate components attached to a common refiner disk. 9. The refiner according to claim 1, characterized in that the inner and peripheral rings are made in one piece on a common basis. 10. The refiner according to claim 1, characterized in that
each plate has a common radius extending to the outer edge of the peripheral ring, each ring has a corresponding width in the radial direction; and
the width in the radial direction of the inner ring is less than the width in the radial direction of the peripheral ring. 11. The refiner of claim 10, wherein the width in the radial direction of the inner ring is less than about 35% of the length of said total radius. 12. The refiner according to claim 10, characterized in that
the width in the radial direction of the feed region of the inner ring is greater than the width in the radial direction of the working region of the inner ring; and
the width in the radial direction of the feed region of the peripheral ring is less than the width in the radial direction of the working region of the peripheral ring. 13. The refiner of claim 10, characterized in that
the pattern of knives and grooves in the working area of the peripheral ring contains at least two zones, one of said zones bordering the peripheral ring feed region, and the other of said zones bordering the outer edge of said peripheral ring; and
the pattern of knives and grooves of said one zone is less dense than the pattern of knives and grooves of said other zone. 14. The refiner according to item 13, wherein the pattern of knives and grooves throughout the working area of the inner ring has the same density. 15. The refiner according to claim 1, characterized in that the grooves along the entire working area of the inner ring are already grooves in the peripheral ring supply area. 16. The refiner according to claim 1, characterized in that
disks rotating relative to each other comprise a rotor disk and an opposite stator disk;
the peripheral ring of the rotor contains curved knives for feeding in the feed area; and
the feed region of the peripheral ring on the stator comprises a substantially flat portion defining a recess for accommodating curved feed knives. 17. The refiner according to claim 1, characterized in that
the refiner clearance includes an internal feed gap between opposing inner feed areas; internal working clearance between opposing internal working areas; a peripheral clearance for feeding between opposing peripheral areas of supply and a peripheral working gap between opposing peripheral working areas; and
the internal working clearance is at a minimum size just before moving to a larger peripheral feed clearance. 18. The refiner according to 17, characterized in that
the width in the radial direction of the feed region of the inner ring is greater than the width in the radial direction of the working region of the inner ring; and
the width in the radial direction of the feed region of the peripheral ring is less than the width in the radial direction of the working region of the peripheral ring. 19. Disk refiner for processing lignocellulosic material, having a pair of opposite rotating relative to each other disks containing plate refiner, including
a first plate having inner and outer radii and a working face containing a pattern of a towering and embossed structure, which when viewed in a direction perpendicular to the axis of rotation, has a varying profile in the radial direction;
a second plate having inner and outer radii and a working face containing a pattern of an elevated and embossed structure, which when viewed in a direction perpendicular to the axis of rotation, has a varying profile in the radial direction, said second plate being opposed in the axial direction and distant from of the first plate, whereby a refiner gap is formed extending in the radial direction, said gap, when viewed in a direction perpendicular to the axis of rotation, has a variable profile from the inner to the outer radius of the plates, while
the radially inner feed portion converges radially outward to the inner working portion;
the inner working part extends in the radial direction with a minimum clearance in the range of about 1.5-3.0 mm to the transition part;
the transition part has a sharp increase in the gap of more than about 4.0 mm in the direction of the peripheral working part; and
the peripheral working part converges in the radial direction to the peripheral minimum clearance, which is in the range of about 0.5-1.0 mm. 20. The disk refiner according to claim 19, in which
the front side of at least one of the plates in the gap in the region of the inner supply portion comprises a large pattern of feed knives and grooves;
the front side of the plates at the gap in the area of the inner working part contains a small defibrating pattern of knives and grooves;
the front side of at least one of the plates at the transitional part of the gap contains a large feeding pattern of knives and grooves; and
the front side of the plates at the peripheral working part of the gap contains a small fibrillating pattern of knives and grooves. 21. The disk refiner according to claim 20, wherein the grooves of the defibrating pattern in the region where the internal working clearance is minimal, are already grooves of the large feeding pattern at the transition portion of the gap. 22. Disk refiner for processing lignocellulosic material, having a pair of opposing disks rotating relative to each other, containing corresponding refining plates, including
a first plate having inner and outer radii R _i and R ₀ and a working front side containing a pattern of towering and embossed structures;
a second plate having inner and outer radii R _i and R ₀ and a working front side containing a pattern of towering and embossed structures;
whereby the radially projecting region A for the flow of lignocellulosic material extends from the inner radius R _i to the outer radius R ₀ so that
dA / dr <0 on the segment from R _i to R _a ,
dA / dr> 0 on the segment from R _a to R _b ,
dA / dr <0 on the segment from R _b to R ₀ ,
where R _i <R _a <R _b <R ₀ . 23. The disk refiner according to claim 22, wherein the plate diameter is at least 36 inches, the value A is partially determined by the radially extending gap between the opposing plates, and dA / dr with a radius directly outside of R _a is determined by a combination of said clearance and the transition from a relatively small pattern of knives and grooves on each of the opposite plates on R _a to a large pattern of knives, grooves or recesses directly outside of R _a . 24. A pair of opposing interacting refining elements in the form of plates intended for a refiner with flat disks for grinding and refining lignocellulosic material in a refining gap between two opposite rotating refining disks, in which the elements in the form of plates are designed for their direct location in front of each other on opposite refining disks, characterized in that both elements in the form of plates are made with an inner ring including a knife and both grooves and a peripheral ring including knives and grooves, the knives and grooves on each of the inner rings forming an inner supply region, followed by a peripheral working region, the knives and grooves on each peripheral ring forming an inner feeding region, followed by a peripheral working area, and the gap formed when installing one plate opposite the other, increases between the inner working area and the peripheral supply area. 25. A pair of refining elements according to paragraph 24, wherein the grooves in the inner working region are already grooves in the peripheral feed region. 26. A pair of refining elements according to paragraph 24, wherein the gap is increased near the annular space between the inner and peripheral rings. 27. A pair of opposing interacting refining elements in the form of plates intended for a refiner with flat disks for grinding and refining lignocellulosic material in a refining gap between two opposite rotating refining disks, in which the elements in the form of plates are designed for their direct location in front of each other on opposite refining disks and thus form a radially extending path for the passage of material flow from characterized by the fact that both elements in the form of plates are made by a ring that includes knives and grooves, and a peripheral ring that includes knives and grooves, and the knives and grooves on each of the inner rings form an internal supply region, followed by a peripheral working area, and the knives and grooves on each peripheral ring form an internal supply area, followed by a peripheral working area, and the flow area of the radial flow path formed as a result of the installation of plates opposite one another, increase aetsya between the inner work area and the peripheral area of feed. 28. A pair of refining elements according to claim 27, wherein the grooves of the inner working area are already grooves of the peripheral feed region. 29. A pair of refining elements according to item 27, wherein the gap is increased at the annular space between the inner and peripheral rings. 30. A combination plate attached to a flat disk of a refiner with rotating discs, containing
an inner ring provided with an inner feeding region formed by a first large pattern of knives and grooves and a peripheral working region formed by a first small pattern of knives and grooves;
a peripheral ring provided with an inner region formed by a second large pattern of knives and grooves, and a peripheral working region formed by a second small pattern of knives and grooves; moreover
the grooves of the second large pattern of knives and grooves are already grooves of the first large pattern of knives and grooves, and the grooves of the second small pattern of knives and grooves are already grooves of the first small pattern of knives and grooves. 31. The combination plate according to claim 30, comprising an annular space between the inner and peripheral rings. 32. The combination plate of claim 31, wherein some, but not all, the blades of the peripheral ring feed region extend into said annular space. 33. The combination plate of claim 30, wherein the inner and peripheral rings are separate components. 34. The combination plate according to claim 33, wherein the inner and peripheral rings are attached to a common disk. 35. The combination plate according to claim 30, in which the inner and peripheral rings are made in one piece on a common basis. 36. The combination stove according to claim 30,
having a common radius extending to the outer edge of the peripheral ring, each ring has a corresponding width in the radial direction; and
the width in the radial direction of the inner ring is less than the width in the radial direction of the peripheral ring. 37. The combination plate of claim 36, wherein the radial width of the inner ring is less than about 35% of the length of said total radius. 38. The combination stove according to clause 36, in which
the width in the radial direction of the feed region of the inner ring is greater than the width in the radial direction of the working region of the inner ring; and
the width in the radial direction of the feed region of the peripheral ring is less than the width in the radial direction of the working region of the peripheral ring. 39. The combination stove of claim 38, wherein
the pattern of knives and grooves of the working area of the peripheral ring contains at least two zones, one of said zones bordering on the peripheral ring feed region, and the other of said zones bordering the outer edge of said peripheral ring; and
the pattern of knives and grooves of said one zone is less dense than the pattern of knives and grooves of said other zone. 40. The combination plate according to claim 39, wherein the pattern of knives and grooves has a uniform density throughout the working area of the inner ring. 41. The combination stove according to clause 36, in which
the pattern of knives and grooves of the working area of the peripheral ring contains at least two zones, one of said zones bordering on the peripheral ring feed region, and the other of said zones bordering the outer edge of said peripheral ring; and
the pattern of knives and grooves of said one zone is less dense than the pattern of knives and grooves of said other zone. 42. The combination cooker of claim 30, wherein the large pattern of the knives and grooves of the inner peripheral ring feed region comprises a plurality of curved knives. 43. The combination plate according to claim 42, wherein the knives of the feed region and the working region of the peripheral ring have respective heights, and the curved knives of the feed region have a height greater than the height of the knives of the work region. 44. The combination plate according to claim 30, wherein the peripheral ring feed region has a larger pattern than the working region of the inner ring. 45. Method for thermomechanical refining of wood chips at elevated temperature and pressure, at which
withstand chips in a steam environment to soften it;
soaked and partially pulp softened wood chips in a compression device;
chopped and partially defibrated wood chips are fed at elevated pressure to a primary refiner with rotating disks, in which
each of the opposing discs has a pattern of knives and grooves of the inner ring and a pattern of knives and grooves of the peripheral ring;
each ring contains an inner feed region and a peripheral work region;
essentially completing chip dispersal in the working region of the inner ring;
fibrillate the fibers in the working area of the peripheral ring at which steam is generated;
maintain the increased pressure during said supply by directing a portion of said generated steam around the working region of the inner ring. 46. The method according to item 45, in which the rings are formed in plates attached to the disks, and when the part of the steam is directed, steam is passed through a channel made in the plate at a radius located inside the peripheral working area of the peripheral ring.

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