WO2005085519A1 - Device and method for reducing vapour loss in a closed system - Google Patents

Abstract

The invention relates to a device comprising a container (20) which defines a closed area and through which a solid can be transported in a direction of transportation from an inlet (21a; 21b) to an outlet (22a; 22b). The container is divided into three sections (12, 13, 14) in the direction of transportation. An essentially solid vapour mixture (12) is contained in a first section, an essentially solid liquid vapour is contained in a second section (13) and an essentially solid vapour liquid is contained in an intermediate section (14). A device (27), which is used to guide an essentially non condensable gas into the closed container, is provided on at least one area of the container. The invention also relates to a corresponding method and to the use thereof in a device which is used to treat material, in particular to treat waste paper, repulping or shredding.

Description

 Device and method for reducing steam loss in a closed system

1. Field of the Invention

The present invention relates generally to an apparatus and method for reducing steam loss in a closed system. The device and the method of the present invention are used in particular in the field of the extraction of primary fiber materials (pulping), the processing of secondary fiber materials from waste paper, the material processing in general and the defibration for the production of chipboard. However, other process engineering uses are also conceivable.

2. Background of the Invention

The state of the art in relation to the present invention and the associated technical problem on which the present invention is based are explained on the basis of the processing of secondary fiber material from waste paper. However, the present invention is not limited to this application.

When processing secondary pulp from waste paper, a main task is to remove impurities and / or to upgrade the waste paper so that the secondary fiber is suitable for producing an end product within predetermined specifications. An appropriate degree of sterilization of the pulp before the final processing is necessary, in particular in the production of hygiene articles, such as toilet paper, facial tissues, etc. However, contamination cannot be completely ruled out even if stringent standards apply in relation to the waste paper brought in. Therefore, these contaminants must be handled within the process system before the pulp is further processed into paper. So put z. B. adhesives and coatings, but above all germs are conventional impurities in secondary fiber from waste paper. A main factor in the processing of secondary fiber from waste paper is therefore, among other things, disinfection.

For better understanding, a system for processing secondary fiber from waste paper is shown schematically in FIG. B. is described in DE-A-197 42 729. Only components for disinfection, fractionation or grinding and thinning of the fibrous material are shown in the system. However, it is obvious to the person skilled in the art that such systems can also contain other further components (for example for bleaching, for so-called "deinking", etc.). The system shown in FIG. 1 is a closed system with a material input 1 and a material output 2. In this case, the solid introduced into the system is a fibrous material which, for example, has a certain consistency of approx. 35% OTRO (oven-dry; DIN EN 20 638) and has a temperature of approx. 40 ° C. The fibrous material is introduced into a heating screw 3 via the material entry 1. To disinfect the fibrous material, the heating screw is supplied with live steam by means of a device for supplying live steam 4, so that an environment with a pressure of approximately 1.7 bar and a temperature of 105 to 115 ° C. is established in the heating screw. At these temperatures, the fiber material can be effectively sterilized, which is transported or conveyed in the heating screw and has an appropriate residence time in the screw of, for example, approximately 20 minutes. In such a printing system, the material is preferably introduced by means of a stuffing screw, so that the stuffing screw closes the printing system on the side of the material input. After staying in the Heating screw, during which the fibrous material is continuously conveyed, the fibrous material is discharged from the heating screw and introduced into a disperser 6 via a screw 5. After disinfection, disruptive contents remaining in the fibrous material are dispersed in the disperger 6 and divided into small pieces, so that the end product is not adversely affected by the remaining constituents. The fibrous material is then discharged from the disperser 6 and introduced into a discharge container 8 via a screw conveyor 7. A device for introducing dilution water 9 is used to introduce dilution water into the discharge container 8 in order to make the highly consistent fibrous material pumpable. The pumpable, medium-consistency fibrous material is then discharged from the discharge container 8 via a pump 10 and has a consistency of, for example, approximately 13% OTRO.

The fibrous material is thus conveyed in the conveying direction in the system from the material input 1 to the material output 2. This system is a closed pressure system, which is closed on the one hand by the stuffing screw (not shown) at the material feed and on the other hand by the pumpable fibrous material (essentially a liquid section) by the MC pump at the material discharge.

When the fibrous material is transported from the heating screw 3 to the discharge container 8, live steam, which was fed to the system via the device for supplying live steam 4, is carried along. In order to return steam from the heating screw again, a return line 11 is therefore arranged after the disperser 6 and is intended to return live steam, which emerges from the disperser with the fibrous material, back into the heating screw 3. Nevertheless, live steam is also carried into the discharge container 8 via the fibrous material. Three are thus formed in the discharge container 8 Sections. Essentially, a fiber-vapor mixture is fed to the discharge container 8, so that a fiber-vapor mixture is essentially present in a first section 12 in an upper region of the discharge container 8. As already mentioned, dilution water is supplied to the discharge container 8 via the device for supplying dilution water 9 in order to make the fibrous material pumpable, so that in a second section 13 of the discharge container 8 there is essentially a fibrous substance-liquid mixture. In addition, an intermediate section 14 is formed between the first section 12 and the second section 13, in which a mixing zone is formed from an essentially fiber-vapor-liquid mixture.

It was recognized by the inventor for the first time and with surprise that the vapor carried with the fibrous material into the discharge container 8 condenses on the surfaces of the liquid or the dilution water in the intermediate section 14 and the second section 13 of the discharge container 8. When steam is condensed, there is a sudden drop in pressure in the discharge container 8. As a result of the higher pressure in the heating screw, an increased steam flow is generated from the heating screw 3 into the discharge container 8, so that this steam is disinfected in the heating screw 3 is missing and must be tracked by the device for supplying live steam 4. As a result, there is an increased need for steam, the production of which is associated with considerable energy costs. Furthermore, the return of the steam through the steam return line 11 is reduced by the pressure drop and the associated tendency of the steam to flow into the discharge container 8, which further increases the additional steam requirement. 3. Description of the invention

The technical problem on which the present invention is based is therefore to provide a device and a method which makes it possible to reduce the loss of steam in closed systems and thereby to improve the energy balance of the overall system.

This technical problem is solved by a device according to claim 1 and a method according to claim 20.

Further advantageous embodiments and areas of application are set out in the subclaims.

The device of the present invention is characterized in that it has a container which defines an enclosed space and through which solid transport takes place in a conveying direction from an inlet to an outlet. The solid can be, for example, fiber, wood pulp, wood chips, etc. However, other solids are also conceivable. The container of the device according to the invention is divided in the conveying direction into three sections, of which essentially a solid-steam mixture in a first section, essentially a solid-liquid mixture in a second section and essentially an intermediate section Solid-steam-liquid mixture is present. The device of the present invention further comprises at least one location of the container means for introducing a substantially non-condensable gas into the closed space, whereby the condensation of the steam in the container is reduced and therefore the steam loss of a closed system with the device according to the invention is reduced can. The device for introducing a substantially non-condensable gas is advantageously arranged in the closed space in such a way that the gas can be introduced into the first section, ie the section with the solid-steam mixture. As a result, the non-condensable gas forms a kind of isolation barrier zone from the steam, which effectively reduces the steam condensation in the container. In addition, a kind of displacement body is formed by the gas, which forces the entrained steam back from the condensation surface. However, it is also conceivable to introduce the gas into the second section or the intermediate section.

According to an advantageous embodiment of the present invention, the device for introducing a substantially non-condensable gas into the closed space is designed such that the gas can be introduced into the closed space under pressure. This is particularly necessary when the device of the present invention is used in a pressure system so that this pressure has to be overcome in order to introduce the gas.

Air, inert gas, reactive gas or ozone is advantageously used as the non-condensable gas. The selection of the gas to be used is subject to various considerations, including taking into account the overall system in which the device according to the invention is used. If, for example, a system for processing secondary pulp from waste paper is used, which also includes a bleaching step, it must be taken into account that some gases, such as oxygen, could react with the bleach. This could affect the corresponding process. However, a gas that is reactive could also be used to cause chemical reactions that are useful and beneficial in the process, such as Carbon dioxide to reduce pulp pH. Another possibility is the use of inert gases such as argon, helium, krypton and other gases such as nitrogen. Another factor in the selection is the cost of the gas to be used, for example the production of ozone is comparatively expensive. However, it is essential that the gas is a so-called non-condensable gas.

According to one embodiment of the present invention, the inlet is arranged in such a way that it is connected to the first section, that is to say the section with the pulp / fiber mixture, and the outlet is arranged in such a way that it is connected to the second section, that is to say the section with the solid-liquid mixture. This ensures that the solids are transported in the conveying direction from the first section via the intermediate section to the second section.

Alternatively, however, the inlet could also be arranged in such a way that it is connected to the second section, that is to say the section with the solid-liquid mixture, the outlet being arranged in such a way that it is connected to the first section, that is to say the section with the solid-steam mixture. The solids transport would then take place in a reverse direction and thus in the conveying direction from the second section via the intermediate section to the first section.

The gas of the present invention is advantageously selected such that when the gas is introduced into the container, the condensation of the steam in the closed space, in particular in the intermediate section and the second section, is reduced. As a result, the loss of steam in a closed system can be reduced accordingly with the device according to the invention. The gas fed in can be expediently discharged from the outlet with the solid in the conveying direction, so that it does not remain in the device. In this case, the gas has to be tracked continuously. The gas can also be output elsewhere.

Furthermore, the present invention proposes a device for stock preparation, in particular for waste paper processing, which has a closed system with a heating screw and a discharge container, with a solid being transported in the conveying direction from the heating screw to the discharge container. According to the invention, the discharge container of this device is a device as described above.

According to an advantageous further development of the device for stock preparation, it also has a disperser, which is arranged downstream of the heating screw and arranged upstream of the discharge container in order to cause the pulp to be ground or fragmented, so that remaining constituents can be comminuted so that they can be separated into no longer have a negative impact on the end product.

According to one embodiment, a screw conveyor is arranged between the heating screw and the discharge container or the disperser and the discharge container.

This screw conveyor is, for example, a stuffing screw, but can alternatively also be an inexpensive, conventional screw conveyor which has the function of a valve which is only partially open.

In order to increase the temperature during sterilization, for example when processing secondary fiber from waste paper, the system is advantageously a printing system. In addition, the heating screw advantageously has a device for supplying live steam into the heating screw, for example in order to provide the temperatures which are necessary for disinfection.

Likewise, a device for supplying dilution water into the discharge container can be provided in order to form the second section and to make highly consistent fibrous material pumpable.

Alternatively, the present invention also proposes a device for digestion in a closed system with a refiner and a discharge container. The solids are transported in the conveying direction from the refiner to the discharge container, which according to the invention is a device as described at the beginning of the summary of the invention.

In order to be able to use steam carried along with the fibrous material that was separated from the fibrous material in the cyclone or to use its heat elsewhere in the system or in some other way, the device according to the invention can advantageously have a cyclone and a heat exchanger for digestion, the cyclone being connected downstream of the refiner and is arranged upstream of the discharge container and the heat exchanger is arranged downstream of the cyclone in another conveying branch.

According to one embodiment of the present invention, the cyclone is essentially connected directly to the discharge container.

In addition, the present invention proposes a device for defibration in a closed system. In the present case, fiberization is to be understood as a device in which wood chips (wood chips) are processed so that they For example, can be processed into chipboard. This device according to the present invention has a feed screw and a steam room. The feed screw is advantageously connected to the steam chamber and there is a transport of solids in the conveying direction from the feed screw to the steam room. The feed screw of the device for defibrating the present invention is a device as described at the beginning. As a result, in addition to reducing steam loss, a cost-intensive and energy-intensive stuffing screw as an entry screw can also be dispensed with in comparison with the prior art.

The feed screw of the fiberizing device advantageously has an inlet for solids mixed with liquid and a device for removing the liquid from the heating screw. As already mentioned, the feed screw is connected to the steam room and forms the pressure seal for the system at the material feed.

Furthermore, the present invention proposes a corresponding method with the following steps. First of all, a solids transport is generated in a conveying direction from an inlet to an outlet of a container, which defines an enclosed space and is divided into three sections in the conveying direction. The three sections correspond to the three sections of the container described at the beginning. In addition, an essentially non-condensable gas is introduced into the closed space at at least one point of the container.

The developments of the method according to the invention essentially correspond to the developments of the device according to the invention, which was described at the beginning. The method according to the invention, for example in a method, can be used for stock preparation, in particular for processing waste paper, for digestion or for defibration.

4. Brief description of the drawings

The present invention is described in more detail below with reference to the accompanying drawings, so that the advantages and the mode of operation of the present invention become clearer. In the drawings, the same or similar parts have the same reference numerals.

In the drawings:

Figure 1 is a schematic representation of a system for processing secondary fiber from waste paper according to the prior art;

Figure 2 is a schematic view of the device according to the invention;

Figure 3 is a schematic view of a system for processing secondary pulp from waste paper according to the present invention;

FIG. 4 shows a schematic view of a discharge container of the system for processing secondary fiber from waste paper from FIG. 3;

FIG. 5 shows a schematic view of a digestion system according to the present invention;

Figure 6 is a schematic view of a fiberization system in accordance with the present invention. 5. Detailed description of the invention

A device of the present invention is shown purely schematically in FIG.

The device has a container 20 which defines an enclosed space. In addition, an "inlet" 21a and 21b and an "outlet" 22a and 22b are provided. According to an exemplary embodiment, solids are introduced via inlet 21a, whereas solids are discharged via outlet 22a. This variant is shown by the solid arrows 23 and 24. Alternatively, the substance can also be introduced through the inlet 21b and the substance can be discharged via the outlet 22b. This variant is shown by the dashed arrows 25 and 26.

The closed space defined by the container 20 is divided into three sections 12 to 14, of which a solid-steam mixture is present in a first section 12 and a solid-liquid mixture is present in a second section 13. In an intermediate section 14 arranged between them, there is a kind of mixing zone from the two sections 12, 13, so that a solid-steam-liquid mixture is formed. These mixed states can also contain other components in small amounts, such as chemical residues or other contaminants. It will also be apparent to those skilled in the art that the boundaries between the sections are fluid and rather correspond to further areas and zones.

According to two alternative embodiments, the solids transport takes place on the one hand through the inlet 21a in the direction 23 in the order of the first section 12, the intermediate section 14 and the second section 13 from the outlet 22a in the direction 24. In an alternative embodiment, the solids transport follows exactly in the reverse direction, namely through the inlet 21b in the direction 25 in the order of the second section 13, via the intermediate section 14 and the first section 12 from the outlet 22b in the direction 26.

In addition, the device has a device for introducing a non-condensable gas 27 which, in the embodiment shown, which corresponds to the first embodiment variant with the inlet 21a and the outlet 22a, is connected to the first section 12. In addition, a device for introducing a liquid medium 28 is also provided, which is connected to the section 13 and can serve to form the sections. However, this device 28 is not absolutely necessary. Thus, as can be seen in the following (see description of FIG. 6), a substance can also be introduced in a solid-liquid mixture and steam can flow in through the outlet in order to form the sections. In this case, however, a device for discharging liquid would have to be provided. As already mentioned, the arrangement shown applies only to a solids transport in the direction of the arrows 23, 24. If the solids transport takes place in the opposite direction according to the arrows 25, 26, the device for introducing the non-condensable gas according to this exemplary embodiment would be with the section 12 arranged in connection.

By introducing a non-condensable gas into the container, a type of "insulation barrier layer" is built up, which vapor condensation of steam, which is carried along with the solid when the solid is introduced, ie introduced into the container, on the surface of the liquid medium both in the intermediate section 14 , as well as the second section 13 is reduced. This can effectively prevent the steam condensation from causing a sudden pressure drop in the container 20, which would cause undesired steam flow into the device of the present invention could result. Furthermore, steam loss through the condensation can be prevented effectively. Consequently, the steam loss in a closed system can be effectively reduced with this device.

In FIG. 3, the present invention is described purely by way of example using a system for processing secondary fiber material from waste paper and the advantages and mode of operation are explained in more detail.

The system shown in FIG. 3 essentially corresponds to the schematic system that was explained with reference to FIG. 1 in the introduction to the description. The system shown is a closed system, in which a solid input in the form of a fiber with a certain consistency, such as 35% OTRO, is introduced. This fibrous material is conveyed through several devices until it is finally introduced into a discharge container 8. Dilution water is fed to this discharge container 8 via a device 28 in order to make the fibrous material pumpable, so that a solids discharge or fibrous substance discharge, for example a medium-consistent fibrous substance with approx. 13% OTRO, can take place via a pump 10. The device for feeding in the dilution water 28 preferably comprises four feed lines for the dilution water, which are positioned tangentially on the application container 8, which has a substantially circular cross section. The feed lines are distributed over the edge or the circumference of the container and are each offset by an angle of approximately 90 °. Furthermore, they are positioned in a step-like shape in the axial direction of the container. In other words, the feed lines are connected to the container at different heights, which differ approximately in a range from 100 mm to 500 mm, in particular by 300 mm. With this arrangement, the in The floc-shaped, highly consistent fibrous material introduced into the container is forced into a rotation, so that in combination with the application and feeding of fibrous material from or into the container, a screw-like conveying movement of the fibrous material in the container is generated at least in the lower region of the container (section 13) , The system shown also has a heating screw 3, which is supplied with live steam to sterilize the fiber (secondary fiber from waste paper). The live steam used for the feed has, for example, a temperature of approximately 135 ° C. and a pressure of 3.5 bar. As a result, temperatures between 105 ° C. and 115 ° C. at a pressure between approximately 1.2-2 bar, in particular approximately 1.7 bar, are created in the heating screw, which are advantageous for disinfecting the fibrous material. The residence time of the fibrous material during sterilization is between approximately 10 to 30 minutes, in particular approximately 20 minutes, which is considered sufficient. The fibrous material is continuously conveyed in the heating screw 3 until it is discharged from the heating screw 3.

The heating screw 3 is connected via a screw 5 to a disperser 6, which serves to comminute and distribute remaining constituents in the fibrous material such as, for example, ink particles adhering to the fibers or distributed between the fibers, so that they have no negative effects on the end product , In addition, the disperger 6 is connected to the discharge container 8 via a screw conveyor 7, which according to a preferred embodiment has the function of a partially open valve. With essentially balanced pressure conditions before and after the disperger 6, which are necessary to enable the disperger 6 to operate reliably, a steam return line 11 is connected on the one hand downstream of the disperger and on the other hand connected to the heating screw 3, so that a Steam can be returned from a position downstream of the disperser to the heating screw.

As already mentioned at the beginning, with the fibrous material during transport in the conveying direction, steam which was fed into the heating screw 3 is carried from the heating screw via the screw 5 through the disperser 6 via the screw conveyor 7 into the discharge container 8. In addition, a high mechanical work is carried out on the fibrous material in the disperser 6. This high mechanical work is partially converted into heat by friction, which leads to further evaporation of the liquid content contained in the fiber. This additional steam generated by the frictional heat carried along is carried in addition to the steam from the heating screw with the fibrous material in the conveying direction, so that steam reaches the discharge container 8. A mixing zone is formed in the discharge container 8 by the supply of dilution water via the device 28, so that essentially three sections are formed in the discharge container 8. A fiber / steam mixture essentially forms in a first section 12, this first section 12 being arranged in the uppermost region of the discharge container 8 at which the solids are introduced into the discharge container 8. Another area is the area 13, in which essentially a fiber-liquid mixture is formed, which can be discharged from the discharge container 8 in the direction 2 by means of a medium consistency pump 10. A mixing zone is formed between the two sections 12 and 13, in which both fiber material and steam and liquid are present. In the present embodiment, the solid according to the invention is a fibrous material.

FIG. 4 shows the discharge container 8 of the system from FIG. 3 in an enlarged view and the three sections have been visualized schematically. By the Introducing dilution water into the discharge container 8 forms the three sections mentioned above. As can be seen from FIGS. 3 and 4, the device for supplying dilution water can be formed above or below the boundary between the intermediate section 14 and the section 13 of the solid-liquid mixture.

The surface of the section with the solid-liquid mixture and the surface of the liquid portions in the intermediate section 14 form in the discharge container 8 a "colder" condensation surface in comparison to the temperature of the supplied pulp and the steam. The vapor introduced into the discharge container 8 with the fibrous material would therefore tend to condense on this surface, so that a sudden pressure drop would occur in the discharge container 8 during the condensation. This pressure drop would lead to an increased steam flow from the heating screw 3 into the discharge container 8, so that the steam would escape from the heating screw 3, which in turn would have the consequence that new live steam 4 is introduced into the heating screw via the device for supplying live steam would. The generation of live steam, however, requires a large amount of energy, so that this effect would be disadvantageous and should be avoided.

According to the exemplary embodiment of the present invention, the discharge container 8 is assigned a device for introducing a non-condensable gas for this purpose, which is connected to the section 12 in the exemplary embodiment. Since the present system is a pressure system, the gas, for example air, is pressed against the pressure in the system. The non-condensable gas tends to flow to a cold surface. In the present case, the section 13 and the liquid components in the intermediate section 14 form the cold surface to which the non-condensable gas flows. This forms in the Discharge container 8 a kind of insulation barrier layer, which reduces the condensation of the steam in the discharge container 8 on the previously described condensation surface. As a result, the pressure drop in the discharge container 8 can be reduced or even excluded, so that the increased (compared to the prior art) steam flow from the heating screw 3 into the discharge container 8 is avoided. As a result, the live steam introduced into the heating screw 3 can be used more effectively for disinfection and less live steam has to be supplied via the device 4. Therefore, the energy requirement of the system according to the invention is significantly lower compared to a comparable system of the prior art. As a result, a significant amount of energy costs are saved.

In comparative experiments with respect to the system described in FIG. 3, the effects of reducing the steam loss in the discharge container 8 were examined and proven. The same system was operated on the one hand without introducing a non-condensable gas into the discharge container 8 and on the other hand with blowing or introducing the non-condensable gas.

The solids input 1 was made with a fibrous material which had a consistency of approx. 35% OTRO and was 12 tons per hour (t / h) in the comparative tests. In addition, the amount of dilution water fed to the discharge container 8 was 83.8 t / h with an approximate container volume of 3.275 m ³ (height of the container = 3275 mm, inside diameter of the container 1000 mm).

When operating the system without feeding a non-condensable gas into the discharge container 8, a steam quantity of approx. 5.2 t / h was necessary in order to achieve the corresponding conditions in the heating screw of approx. 1.7 bar and approx. 105 to 115 ° C to ensure and cause sufficient disinfection. In the comparative tests, the plant was operated in the same way, but air was additionally pressed into the discharge container 8 as a non-condensable gas. The amount of air in the comparative tests was approximately 0.042 t / h. This had the effect that the amount of steam required for the heating screw 3 in order to create the same conditions in the heating screw 3 and to bring about the same disinfection was reduced to only about 4.2 t / h. As a result, the amount of steam required was reduced by approx. 19% and thus the steam loss was reduced by 19%. This was also associated with a correspondingly reduced energy requirement and overall lower energy costs.

In addition, it was found that in the prior art plant, the temperature of the dispensed fiber was about 80 ° C, whereas the temperature of the dispensed fiber in a plant according to the present invention was between about 66 ° C and about 70 ° C. This also shows that the heat transfer between the steam and the pumpable pulp, i.e. H. generally the liquid, could be significantly reduced by the inventive design.

FIG. 5 shows another exemplary embodiment of a device for digestion according to the present invention. However, the representation is purely exemplary and the system could include additional components. So these plants are generally multi-stage, as is known to those skilled in the art. The system shown schematically represents a TMP or CTMP method for digestion. However, the present invention is not limited to such a method. Rather, any method of digestion can be used. The digestion system shown in FIG. 5 represents a closed system. In the system there is a material input 1 in the form of wood chips into an entry screw 34. In this screw 34, the wood chips are heated to 160 ° C., for example. The present system is also a pressure system that operates at between about 5 to about 8 bar. After the feed screw 2, the wood chips (solid) are introduced into a refiner 6. This refiner is driven by a motor M and generally requires a large amount of energy. In this step, the wood chips are crushed in the refiner 6 and cut into small pieces. In other words, the wood chips are broken down as completely as possible into individual fibers by the refiner work introduced in accordance with the process objective. Since this is a technical process that has an impact on efficiency, this is only possible to a certain extent. A part of the wood chips remains as a chip material (chips are fiber bundles), which is then treated in a subsequent process step with a similar workflow with the same basic objective (multi-stage). In addition, there are fiber fragments up to so-called flour as constituents of the wood pulp, which are actually undesirable and are excreted from the system if possible. The energy applied via the motor M is applied to the wood pulp in the refiner in the form of mechanical work. The frictional heat generated in this way evaporates the liquid content in the wood pulp or wood chips, so that the refiner leaves a mixture of steam and fibrous material.

The fibrous material with the steam is then conveyed further into a cyclone 29 in which the steam is to be separated from the fibrous material. The cyclone 29 is connected on the one hand to a further delivery line in its upper region, which is to discharge the steam via a heat exchanger 30, so that its heat can be reused or used in another process of the system. On the other hand, the cyclone 29 is connected to a discharge container 8.

In the prior art, the connection between the cyclone 29 and the discharge container 8 is preferably made via a stuffing screw, another conventional screw conveyor or similar systems. In these cases, the discharge container in the prior art is always designed to be open, so that steam which is fed into the container via the screw with the fiber material escapes and is lost. According to the exemplary advantageous embodiment of the present invention, however, the cyclone 29 is connected directly to the discharge container 8. As a result, the additional components such as the screw, stuffing screw or other devices between the cyclone and the discharge container can be saved, which leads to a considerable reduction in the cost of the overall system. The discharge container 8 is, however, designed to be closed. In addition, the connection between the cyclone and the order container could take place in a manner similar to that described in FIG. 3 via a screw conveyor, which has the mode of operation of a partially open valve. Alternatively, this could also be achieved by designing the opening between the cyclone and the discharge container.

Similar to the system described with reference to FIG. 3, the vapor entrained with the fibrous material would condense on the liquid surface in the intermediate section 14 and the section 13, which in turn would also lead to a pressure loss in the discharge container 8 with this device. This would cause an increased steam flow in the direction of the discharge container 8, so that a smaller amount of steam or its thermal energy could be used via the heat exchanger. Thus the steam would be lost in the present system. According to the invention, however, a device for introducing a non-condensable gas into the discharge container 8 is provided. As a result, similar to that described in relation to the system of FIG. 3, a type of insulation barrier layer is generated which reduces the steam condensation in the discharge container 8, so that the pressure in the discharge container 8 can be kept essentially constant. This prevents an increased flow of steam in the direction of the discharge container 8 and the steam in the system can be used effectively via the heat exchanger 30. This significantly improves the overall energy balance of the closed system and reduces the loss of steam due to condensation.

Finally, a further application example of the device of the present invention is shown in FIG. Thus, FIG. 6 shows a device for defibering, the end product after the defibering can be used for processing chipboard or pressed wood panels (MDF), for example.

Such devices have an entry screw 31 and a steam room 32. This system is also a closed system, in which the wood chips (wood chips, chips) in the steam room are defibrated at a pressure of approx. 10 to approx. 15 bar and a temperature of approx. 170 ° C before they are removed the steam room. Subsequently, these wood chips are ground in a refiner, for example, and blown out directly from them in order to be further processed. In order to achieve the prevailing environment in the steam room from approx. 10 to approx. 15 bar at a temperature of approx. 170 ° C., fresh steam is supplied to the steam room, specifically via a device 4. In order to place the pressure system opposite the material feed 1 of the feed screw 31 To complete, a stuffing screw has been provided in the prior art, which is a considerable one Size and has an enormous energy requirement in the order of 1000 KW.

The device according to the present invention, on the other hand, has a conventional feed screw, which is smaller than a stuffing screw and has a much lower energy requirement of the order of 200 KW. In order to complete the printing system with respect to the material input 1 in the device according to the invention, the wood chips are introduced via the material input 1 with a high liquid content, so that a section 13 is formed with a solid (wood chip) / liquid mixture which is similar to the system 3 forms the conclusion. The wood chips are subsequently conveyed from the feed screw 31 into the steam room 32. The feed screw 31 of the exemplary embodiment in FIG. 6 furthermore has a device 33 for removing the liquid introduced with the wood chips from the feed screw. Steam flows in from the steam room through the outlet of the feed screw. Thus, three sections 12 to 14 also form in the feed screw 31.

In a section 13 there will be essentially a solid-liquid mixture, whereas in a section 12 there will essentially be a solid-vapor mixture. Between these two sections, a mixing zone is also formed in an intermediate section 14, in which there is essentially a solid-vapor-liquid mixture. Consequently, even in such a system there would be the problem that the live steam introduced into the vapor space 32 would condense on the liquid surface in the feed screw 31. This would lead to a pressure drop in the feed screw 31, so that an increased steam flow from the steam space 32 into the feed screw would take place. However, this would result in increased steam loss and therefore increased Lead energy amount because more live steam 4 would have to be supplied.

According to the invention, however, the present device has a device for feeding a non-condensable gas into the feed screw 31. The non-condensable gas is preferably fed in in section 12 or section 14. The non-condensable gas forms a type of insulation barrier layer in the feed screw 31, which prevents the condensation of the vapor on the liquid surface in the feed screw 31 (in the sections 12, 14) is reduced so that the pressure in the feed screw 31 remains essentially constant. Consequently, an increased steam flow from the steam chamber 32 into the feed screw 31 is also reduced. As a result, the total amount of energy required to generate the live steam is reduced, which leads to an improved energy balance of the overall system. Furthermore, the connection between the feed screw 31 and the steam chamber 32 is designed, for example, in the form of a partially open valve in order to prevent the gas fed in from escaping into the steam chamber.

In addition, the device according to the invention is advantageous over the prior art because the system can be terminated via a conventional feed screw in the broadest sense and does not have to be via a stuffing screw. Since the energy requirement of a conventional feed screw is significantly lower than that of a stuffing screw, this also reduces the energy requirement of the overall system. In addition, both the size and the cost of the overall system are reduced by the device according to the invention.

The present invention has been explained in detail purely in principle and explained purely by way of example using three advantageous embodiments and areas of application. It is that However, one skilled in the art can see that the present invention can also be applied to other systems, for example in the chemical industry, for example in the production of catalysts, dispersions or plastics and in particular in process engineering, so that the present invention is not restricted to the application examples described, but is only defined by the accompanying claims.

Claims

claims 1. Device with a container (20) which defines a closed space and through which a solid transport takes place in a conveying direction from an inlet (21a; 21b) to an outlet (22a; 22b), the container being divided into three sections in the conveying direction (12, 13, 14) is divided, of which in a first section essentially a solid-steam mixture (12), in a second section (13) essentially a solid-liquid mixture and in an intermediate section ( 14) there is essentially a solid / vapor / liquid mixture, a device (27) for introducing a substantially non-condensable gas into the closed space is provided at at least one location on the container. 2. Device according to claim 1, wherein the device (27) for introducing a substantially non-condensable gas into the closed space is arranged such that the gas can be introduced into the first section. 3. Apparatus according to claim 1 or 2, wherein the device (27) for introducing a substantially non-condensable gas into the closed space is designed such that the gas can be introduced under pressure into the closed space. 4. Device according to one of claims 1 to 3, wherein the non-condensable gas is selected from the group consisting of air, inert gas, reactive gas and ozone. 5. Device according to one of claims 1 to 4, wherein the inlet (21a) is arranged such that it communicates with the first section (12) and in which the outlet (22a) is arranged such that it communicates with the is connected to the second section (13) so that the solids are transported in the conveying direction from the first section (12) via the intermediate section (14) to the second section (13). 6. Device according to one of claims 1 to 4, wherein the inlet (21b) is arranged such that it communicates with the second section (13) and in which the outlet (22b) is arranged such that it communicates with the is connected to the first section (12) so that the solids are transported in the conveying direction from the second section (13) via the intermediate section (14) into the first section (12). 7. Device according to one of the preceding claims, wherein the gas is selected such that when the gas is introduced into the container (20) condensation of the steam in the closed space, in particular in the intermediate section (14) and the second section (13 ) is reduced. 8. Device according to one of the preceding claims, wherein the gas fed in can be discharged with the solid in the conveying direction from the outlet (22a). 9.Device for stock preparation, in particular the processing of waste paper in a closed system with a heating screw (3) and a discharge container (8), solid transport in the conveying direction from the heating screw (3) to the discharge container (8), characterized in that the Discharge container is a device according to one of claims 1-3 and 5-6. 10. The device according to claim 9, further comprising a disperser (6) which is arranged downstream of the heating screw (3) and is arranged upstream of the discharge container (8). 11. The device according to claim 9 or 10, wherein a screw conveyor (7) is arranged between the heating screw (3) and the discharge container (8) or the disperser (6) and the discharge container (8). 12. The device according to claim 11, wherein the conveyor screw (7) is a stuffing screw. 13. The apparatus of claim 11, wherein the screw conveyor (7) has the action of a partially open valve. 14. Device according to one of claims 9 to 13, which is a printing system. 15. The device according to one of claims 9 to 14, further comprising a device (4) for supplying live steam into the heating screw (3). 16. The device according to one of claims 9 to 15, further comprising a device (28) for supplying dilution water into the discharge container (8) to form the second section (13). 17. Device for digestion in a closed system with a refiner (6) and a discharge container (8), solid transport in the conveying direction from the refiner (6) to the discharge container (8), characterized in that the discharge container (8) is a device according to any one of claims 1-5 and 7-8. 18. The apparatus of claim 17, further comprising a cyclone (29) and a heat exchanger (30), the cyclone downstream of the refiner (6) and the discharge container (8) arranged upstream and the heat exchanger (30) the cyclone (29 ) is arranged downstream in another conveyor branch. 19. The apparatus of claim 17 or 18, wherein the cyclone (29) is substantially directly connected to the discharge container (8). 20. Device for defibrating in a closed system with an entry screw (31) and a steam room (32), with a solid being transported in the conveying direction from the entry screw (31) to the steam room (32), characterized in that the entry screw (31) is a device according to one of claims 1, 2 and 4-6. 21. The apparatus of claim 20, wherein the feed screw (31) has an inlet (1) for liquid-mixed solid and a device (33) for removing the liquid from the heating screw, and in which the feed screw (31) with the steam space (32) communicates. 22. The method comprising the steps: generating a solid transport in a conveying direction from an inlet (21a; 21b) to an outlet (22a; 22b) of a container (20) which defines an enclosed space and is divided into three sections (12- 14) is divided, of which in a first section (12) essentially a solid-steam mixture, in a second section (13) essentially a solid-liquid mixture and in an intermediate section (14) in between There is essentially a solid-vapor-liquid mixture, and introducing a substantially non-condensable gas into the closed space at at least one location on the container. 23. The method of claim 22, wherein the substantially non-condensable gas is introduced into the first section. 24. The method of claim 22 or 23, wherein the substantially non-condensable gas is introduced under pressure into the closed space. 25. The method according to any one of claims 22 to 24, wherein the non-condensable gas is selected from the group consisting of air, inert gas, reactive gas and ozone. 26. The method according to any one of claims 22 to 25, wherein the solids transport in the conveying direction from the first section via the intermediate section is generated in the second section. 27. The method according to any one of claims 22 to 25, wherein the solid transport in the conveying direction is generated from the second section via the intermediate section into the first section. 28. The method according to any one of claims 22 to 27, wherein the gas is selected such that when the gas is introduced into the container, condensation of the steam in the closed space, in particular in the intermediate section and the second section, is reduced. 29. The method according to any one of claims 22 to 28, in which the gas fed in is discharged with the solid in the conveying direction from the outlet. 30. Use of the method according to one of claims 22 to 26 and 28 to 29 in a process for stock preparation, in particular for waste paper processing. 31. Use of a method according to one of claims 22 to 26 and 28 to 29 in a method for digestion. 32. Use of a method according to any one of claims 22 to 25 and 27 to 29 in a process for defibration.