CN114729506B

CN114729506B - Device and method for impregnating a material to be conveyed

Info

Publication number: CN114729506B
Application number: CN202080081223.9A
Authority: CN
Inventors: 迪特玛尔·乌尔姆
Original assignee: Andritz AG
Current assignee: Andritz AG
Priority date: 2019-11-25
Filing date: 2020-08-18
Publication date: 2023-09-19
Anticipated expiration: 2040-08-18
Also published as: CA3154512A1; WO2021104691A1; EP4065763C0; AT522964A4; EP4065763B1; CA3154512C; AT522964B1; EP4065763A1; CN114729506A

Abstract

The invention relates to a method for impregnating a material to be conveyed, wherein the material to be conveyed is fed by a compression screw conveyor (2), impregnated and compressed into a gas-and liquid-tight plug. The invention is characterized in that the degree of impregnation of the material to be conveyed is controlled by the relative positioning of the screw (6) and the stopper tube (8). The invention also relates to a device for carrying out the method and enabling optimal control of the impregnation of the fibre pulp.

Description

Device and method for impregnating a material to be conveyed

Technical Field

The invention relates to a method for impregnating a material to be conveyed, such as wood chips, wherein the material to be conveyed is conveyed by means of a compression screw conveyor, which receives the material to be conveyed in an inlet zone and a screw rotating about an axis of rotation in a housing conveys the material to be conveyed to a discharge zone and impregnates the material to be conveyed, the material to be conveyed being compressed between a plug tube and the screw into a gas-and liquid-tight plug, which forms a seal between the discharge zone and the compression screw conveyor. The invention also relates to a device for impregnating a material to be conveyed.

Background

Compression screw conveyors are used not only for dewatering the material to be conveyed by compression, but also for impregnating the material to be conveyed. In this case, impregnation means softening or defibrating the material to be conveyed, wherein the combination of conveying and compression in the compression screw conveyor results in delamination of the cell walls and mechanical defibration of the material to be conveyed, i.e. a reduction of the material to be conveyed into its fibrous component, while at the same time producing a correspondingly larger specific surface area of the material to be conveyed. The compression screw conveyor also allows for the use of a device in the compression screw conveyor and connected to the discharge zoneA pressure seal is made between (e.g. the reactor) as the material to be conveyed forms a gas-and liquid-tight plug between the inlet zone and the discharge zone. This is necessary because the connected equipment (e.g., reactor) is filled with a gaseous or liquid fluid containing the reactants, which must be isolated from the environment. The means connected to the discharge zone of the compression screw conveyor may be designed as a pressure vessel, for example, an atmospheric or pressurized reactor, digester (digger) or the like. Reactants are in particular chemicals in liquid fluids (e.g. solvents, aqueous solutions, ethanol or similar mixtures), where the term "chemical" may be a catalyst, such as an acid (e.g. H) ₂ SO ₄ Or acetic acid), a base (e.g., naOH), or the like. Typical uses are found in the pulp and paper industry, and are also commonly used in the processing of fibrous slurries, such as wood pulp, e.g., for the production of fiberboard, medium Density Fiberboard (MDF), and the like. An important field of application, therefore, is, in addition to the treatment of the material to be conveyed in digesters, impregnation of the material to be conveyed, in which case a compression screw conveyor can discharge air and liquid from the material to be conveyed and impregnate the material, wherein the impregnated material to be conveyed is fed from the compression screw conveyor to a reactor containing the reactants required for impregnation. Another use may be for the production of biofuels, for example bioethanol may be produced from biomass including cereal crops, corn or sugar beets.

Compression screw conveyors generally consist of a housing with a screw mounted rotatably about an axis of rotation, wherein the screw has at least partially a helical line and the material to be conveyed is increasingly compressed in a conical region between the housing and the screw. In the discharge zone of the compression screw conveyor, the screw is at least partially free of a spiral in order to form the plug. The housing may have openings in the screw region to allow dewatering and/or venting of the material to be conveyed by compression. Conventional compression screw conveyors can be constructed with cylindrical housings along with screws having a cylindrical outer profile, other housing shapes, such as those having a tapered outer profile, are also possible.

EP 2 817 449 B1 describes a system for treating wood-free plant material, wherein a compression screw conveyor for feeding sheet material into a boiler is used, which comprises a stopper tube having a constant inner diameter at the end of the compression screw conveyor. The purpose of EP 2 817 449 B1 is mainly to disclose a compression screw conveyor arrangement with optimized pressure sealing. This is achieved by the interaction of a compression screw conveyor and a forced feed screw.

DE 1 101 126B describes a method and apparatus for impregnating a raw material containing pulp, wherein the material is gradually compressed to expel air and liquid, and the material is in direct contact with the impregnating liquid as it expands. It was also determined that materials reduced to their fibrous components advantageously exhibit a greater surface area for subsequent applications of the impregnated materials.

EP 3 333 B1 describes a method and a device for impregnating biomass. The improved impregnation is mainly achieved by conveying the pre-compressed biomass to the compression screw conveyor by means of a pressure feed screw, since it is noted that pre-compressing a large volume of biomass containing hollow spaces results in a more strongly compressed plug. It was also determined that it is advantageous to determine the filling level of the reactor unit according to the speed of transporting the biomass in order to achieve a uniform impregnation of the biomass.

EP 0 493 B1 relates to a plug screw feeder for use in chip impregnation comprising a variable speed screw and a variable speed pressure feed screw, wherein the speeds of the screw and the pressure feed screw are used to obtain the desired degree of fiber displacement.

Disclosure of Invention

The object of the present invention is to provide an improved possibility for impregnating the material to be transported, in particular pulp. Another technical problem to be solved is to have a better and more uniform effect of the reactants on the impregnation of the pulp. Another technical problem to be solved is to achieve optimal dewatering or to compensate for the effects of uneven material to be conveyed, for example unevenly fed to a compression screw conveyor or having widely dispersed material properties, while achieving the desired impregnation. Another technical problem to be solved is to be able to continue to adjust the impregnation in case of wear of the screw or plug tube and to minimize the power consumption of the compression screw conveyor while maintaining the impregnation requirements.

According to the invention, this is achieved in that the degree of impregnation of the material to be conveyed is controlled by the relative positioning of the screw and the stopper tube. In the housing, a plug pipe (plug pipe) is arranged in the discharge zone of the compression screw conveyor and has at least partially an annular structure and/or at least partially a truncated cone structure. The screw extends into the plug tube, wherein the screw is mounted rotatable about a screw axis and has a region inside the plug tube without a helix to form a plug. The plug tube is usually exchangeable, because it can thus be easily exchanged if worn out, or because a different geometry can be formed by exchanging the plug tube. The area between the stopper tube and the screw is affected by the positioning of the screw relative to the stopper tube. Thus, the area between the stopper tube and the screw, in particular the gap at the end of the screw towards the stopper tube, may be narrowed or widened. The impregnation of the material to be conveyed increases due to the narrowing of the area or gap, while the impregnation of the material to be conveyed decreases due to the widening of the area or gap.

An advantageous embodiment of the invention is characterized in that the screw is moved in an axial direction along the axis of rotation in the housing to control the degree of impregnation. Here, the housing and the plug tube are stationary, while the screw is moved in the axial direction, resulting in a further narrowing or widening of the area between the plug tube and the screw, in particular the gap of the screw end towards the plug tube. The displacement of the screw can be achieved in that the bearing unit of the screw has a displaceable design, wherein the bearing unit accommodates the screw shaft and is arranged opposite the discharge zone. The screw is driven by a fixed drive, wherein a coupling is arranged between the bearing unit of the screw and the drive, which coupling absorbs the axial movement of the screw.

Another preferred embodiment of the invention is characterized in that the plug tube is moved axially along the rotation axis within the housing by 3 to control the degree of impregnation. Here, the housing and the screw are stationary, while the plug tube moves in the axial direction, resulting in a narrowing or widening of the area between the plug tube and the screw (in particular the gap of the screw end towards the plug).

An advantageous embodiment of the invention is characterized in that the material to be conveyed is conveyed from the discharge zone to the reactor, in which the material to be conveyed reacts with the reactants, and in that the reaction result in the reactor is influenced by controlling the degree of impregnation of the material to be conveyed. Controlling the degree of impregnation of the material to be conveyed means controlling the decomposition of the material to be conveyed and thus the controlled decomposition of the material to be conveyed into its fibrous components and implicitly controlling the specific surface area of the chopped material to be conveyed, which is important in chemical processes and also in absorption and adsorption processes. Only in the case of controlled impregnation, the optimum effect of the reactants in the reactor on the material to be conveyed and thus the optimum reaction result is possible. The concept of reaction results here includes, mainly and respectively, the extent of impregnation, the penetration of the reactants, the quality of the product and the yield, in relation to the material to be conveyed.

An advantageous embodiment of the invention is characterized in that the material to be conveyed is compressed between the inlet zone and the discharge zone between the housing and the region of the screw which at least partially comprises the spiral, wherein a plug is formed in the discharge zone between the plug tube and the non-spiral region of the screw. In the plug zone, the screw may have a region with a spiral in part, wherein the non-spiral region of the screw follows the spiral region of the screw in the conveying direction.

A further preferred embodiment of the invention is characterized in that the plug passes through an annular zone in the discharge zone, which consists of a region of the plug tube with a constant inner diameter and a region of the screw without a spiral with a constant outer diameter. In particular, a plug is formed in the annular region, wherein in this region the impregnation of the material to be conveyed has not yet been controlled. The plug is advantageously passed first through the annular zone to form a sealing plug and then through the calibration zone to regulate impregnation.

A similar advantageous embodiment of the invention is characterized in that the plug passes after the annular region in the discharge region through a calibration region, which is formed by a region of the plug tube with an inner diameter decreasing in the conveying direction and by a non-helical region of the screw with a constant or decreasing outer diameter, or by a region of the plug tube with an inner diameter constant or increasing in the conveying direction and by a non-helical region of the screw with an increasing outer diameter. If the calibration zone is formed by a region of the stopper tube having a constant inner diameter in the conveying direction and 4 by a helix-free region of the screw having an increased outer diameter, then a region having a diameter greater than the constant inner diameter of the stopper tube is adjacent to the stopper tube. Here, the area of the screw without the spiral with the increased outer diameter may be located inside the stopper tube or in an area with a diameter larger than the inner diameter of the stopper Guan Hengding, but positioning between these positions is of course also possible. Due to the relative positioning of the stopper tube and the screw, a certain distance is provided between the stopper tube and the screw in the calibration zone, in particular a certain gap is provided at the end of the screw facing the stopper tube. The calibration zone may be reduced or enlarged by the relative positioning of the stopper tube and the screw. The region of the stopper tube with the reduced inner diameter can be realized with a conical stopper tube, wherein the imaginary conical tip points towards the discharge zone. The area of the screw without spiral, having a constant diameter or a reduced outer diameter, is then conically formed, the imaginary cone tip pointing again towards the discharge zone. The distance from each other and the impregnation are also directly controlled by the movement between the conical surfaces located inside each other. The use of a tapered plug tube makes it possible to obtain a region of the plug tube with an increased inner diameter, with the notional cone tip pointing towards the inlet region. The helix-free region of the screw with increased outer diameter is then conically formed, the imaginary cone tip pointing again towards the inlet region. In this way, advantageously, thanks to the axial movement of the screw, the impregnation of the material to be conveyed can be increased by shrinking the calibration zone or can be reduced by enlarging the calibration zone.

The technical problem underlying the present invention is also to provide a compression screw conveyor for impregnating a material to be conveyed, such as wood chips.

An advantageous embodiment of the compression screw conveyor is characterized in that the screw can be moved in the axial direction along the rotation axis and relative to the housing, or the plug tube can be moved in the axial direction along the rotation axis and relative to the housing and the screw.

Furthermore, an annular region is advantageously formed between the plug tube and the screw, which comprises a region of constant inner diameter of the plug tube and a region of no spiral of constant outer diameter of the screw.

A similarly advantageous embodiment of the compression screw conveyor is characterized in that a calibration zone is formed between the stopper tube and the screw, wherein the calibration zone also comprises a region of the stopper tube having a decreasing inner diameter in the conveying direction and a non-helical region of the screw having a constant or decreasing outer diameter, or the calibration zone comprises a region of the stopper tube having a constant or increasing inner diameter in the conveying direction and a non-helical region of the screw having an increasing outer diameter. If the calibration zone is formed by a region of the stopper tube having a constant inner diameter in the conveying direction and a region of the screw having an increased outer diameter without a spiral, a region 5 whose diameter is greater than the constant inner diameter of the stopper tube is adjacent to the stopper tube. The reduced or increased area of the screw or stopper tube may be formed by a stopper tube or screw having a conical shape. According to these embodiments, the axial positioning of the screw relative to the stopper tube allows the size of the calibration zone to be reduced or increased.

Drawings

The invention will now be described by way of example with reference to the accompanying drawings.

Fig. 1 shows a compression screw conveyor for impregnation according to the prior art.

Fig. 2 shows an embodiment of a compression screw conveyor according to the invention, wherein the screw and the stopper tube are in a first relative position.

Fig. 3 shows an embodiment of the compression screw conveyor according to the invention, wherein the screw is in a second relative position with respect to the stopper tube.

Fig. 4 shows another embodiment of a compression screw conveyor according to the invention.

Detailed Description

Fig. 1 shows a compression screw conveyor for impregnation according to the prior art. The material to be conveyed is fed here via an inlet zone 3 to a compression screw conveyor 2 and to a reactor 1, not shown here, wherein the compression screw conveyor 2 has a housing 4, a screw 6 rotatable about a rotation axis 5, which has a spiral 9 at least in part, a discharge zone 7 and a plug tube 8. In the region of the stopper tube 8, the screw 6 has a region 10 without a spiral.

Fig. 2 and 3 show an embodiment of a compression screw conveyor according to the invention, wherein fig. 2 shows a first relative position of the screw and the stopper tube and fig. 3 shows a second relative position of the screw and the stopper tube. A screw 6 which is rotatable about a screw axis 5 and which has a spiral 9 at least in part is mounted in the housing 4. In the discharge zone 7, the screw 6 has a region 10 without a spiral in the stopper tube 8, the stopper tube 8 and the screw 10 without a spiral form an annular zone 11, and in the conveying direction of the material to be conveyed, a calibration zone 12 is arranged after the annular zone 11. Furthermore, the screw's helix-free region with increasing outer diameter 16 is designed to be conical, the imaginary cone tip pointing towards the inlet region and the stopper tube 8 having a constant inner diameter in the conveying direction. The calibration zone is formed by a region of constant inner diameter of the stopper tube and a region of no spiral 16 of increased outer diameter of the screw, wherein a region 15 of diameter greater than the inner diameter of the stopper Guan Hengding is adjacent the stopper tube. In fig. 2, the area 16 of the screw without spiral having an increased outer diameter is located in an area 15 of diameter greater than the inner diameter of the plug Guan Hengding, whereas in fig. 3 the area 16 of the screw without spiral 6 having an increased outer diameter is located in the plug tube 8. Advantageously in this way, thanks to the axial movement of the screw 6, the impregnation of the material to be conveyed can be increased by narrowing the calibrated zone 12 or can be reduced by increasing the calibrated zone. Fig. 2 shows a compression screw conveyor 2, in which the relative positioning of the screws 6 is farther in the conveying direction of the material to be conveyed, i.e. closer to the discharge zone 7. In contrast, fig. 3 shows a compression screw conveyor 2, in which the screw 6 is positioned relatively in the opposite direction to the conveying direction of the material to be conveyed, i.e. closer to the inlet zone 3. The calibration zone 1 in fig. 3 is thus smaller than in fig. 2, so that the positioning of the screw 6 in fig. 3 results in more impregnation of the material to be conveyed, and the positioning of the screw 6 in fig. 2 results in less impregnation of the material to be conveyed.

Fig. 4 shows another embodiment of a compression screw conveyor according to the invention, in which the screw 6 is rotatably mounted in the housing 4, and the screw 6 has at least partly a spiral 9. In the discharge zone 7, the screw 6 has a region 10 without a spiral inside the stopper tube 8, wherein the stopper tube 8 forms an annular region 11 with the region 10 without a spiral of the screw, and a calibration zone 12 is arranged after the annular region 11 in the conveying direction of the material to be conveyed. Furthermore, the screw's helix-free region 14 with an outer diameter decreasing in the conveying direction is designed as a cone, the imaginary cone tip pointing towards the discharge zone 7, and the plug tube 8 having its region 13 with an inner diameter decreasing. Here, arrow a indicates the possibility of relative positioning of the screw 6 with respect to the stopper tube 8, and arrow B indicates the possibility of relative positioning of the stopper tube 8 with respect to the screw 6.

Thus, the present invention provides a number of advantages: an effective means of controlling pulp impregnation and a better and more uniform effect of the reactants on the impregnated pulp. Similarly, optimized dewatering properties and simultaneously controlled impregnation are also possible. It is also possible to select a mode of operation in which the desired degree of impregnation can be set, while this mode has a minimum power consumption of the compression screw conveyor. In this way, wear of the compression screw conveyor, plug pipe etc. can be kept to a minimum, whereas in case the compression screw conveyor, plug pipe etc. has worn, the desired degree of impregnation can still be set. The service life can thus be extended, since worn parts can be replaced later. Likewise, the effect of non-uniform material to be conveyed can be compensated for, since, for example, the material is fed unevenly into the compression screw conveyor, with widely varying material properties or variable composition, wherein in each case the desired impregnation can be set. Furthermore, the solution according to the invention enables a fast start-up of the compression screw conveyor with low power consumption, while the impregnation can be controlled or set up quickly.

List of reference numerals

1. Reactor for producing a catalyst

2. Compression screw conveyor

3. Inlet zone

4. Shell body

5. Axis of rotation

6. Screw rod

7. Discharge zone

8. Plug tube

9. Spiral line

10. Non-helical region of screw

11. Annular region

12. Calibration zone

Area of 13-plug pipe with reduced inner diameter

Spiral-free region of a 14-screw with reduced outer diameter

15 having a diameter greater than the constant inner diameter of the stopper tube

Spiral-free region of a 16-screw with increased outer diameter

Claims

1. Compression screw conveyor for controlling impregnation of a material to be conveyed, comprising an inlet zone (3) for receiving the material to be conveyed, a screw (6) rotatable in a housing (4) about an axis of rotation (5) and a discharge zone (7), wherein in the discharge zone (7) the screw (6) is rotatably mounted within a stopper tube (8), characterized in that the screw (6) comprises at least partly a screw (9), wherein in the region of the stopper tube (8) the screw (6) is at least partly designed as a region (10) free of a screw, and the screw (6) and the stopper tube (8) are movable and positionable relative to each other, wherein a calibration zone (12) is formed between the stopper tube (8) and the screw (6), wherein the calibration zone (12) comprises a region (13) of a reduced inner diameter of the stopper tube and a region (14) of a screw free of a constant outer diameter or a region (16) of a screw free of a reduced outer diameter, or the calibration zone (12) comprises a region of a constant inner diameter of the stopper tube or an increased region of a screw free of an outer diameter.

2. The compression screw conveyor according to claim 1, characterized in that the material to be conveyed is wood chips.

3. A compression screw conveyor according to claim 1, characterized in that the screw (6) is movable in an axial direction along the rotation axis (5) and relative to the housing (4).

4. A compression screw conveyor according to claim 1, characterized in that the plug tube (8) is movable in axial direction along the rotation axis (5) and relative to the housing (4) and the screw (6).

5. A compression screw conveyor according to claim 1, characterized in that an annular zone (11) is formed between the plug tube (8) and the screw (6), wherein the annular zone (11) comprises a region of constant inner diameter of the plug tube (8) and a non-helical region (10) of constant outer diameter of the screw (6).

6. A compression screw conveyor according to claim 1, characterized in that the reduction of the calibration zone (12) or the increase of the calibration zone (12) can be achieved by the axial positioning of the screw (6) relative to the plug tube (8).

7. Method for impregnating a material to be conveyed, wherein the material to be conveyed is fed by a compression screw conveyor (2) according to any one of claims 1-5, which compression screw conveyor (2) receives the material to be conveyed in an inlet zone (3), a screw (6) rotating about an axis of rotation (5) within a housing (4) conveys the material to be conveyed to a discharge zone (7) and simultaneously impregnates it, wherein the material to be conveyed is compressed between a stopper tube (8) and the screw (6) into a gas-and liquid-tight plug, which plug forms a seal between the discharge zone (7) and the compression screw conveyor (2), characterized in that the degree of impregnation of the material to be conveyed is controlled by the relative positioning of the screw (6) and the stopper tube (8).

8. The method of claim 7, wherein the material to be conveyed is wood chips.

9. Method according to claim 7, characterized in that the screw (6) is moved axially along the rotation axis (5) within the housing (4) to control the degree of impregnation.

10. A method according to claim 7, characterized in that the plug tube (8) is moved axially along the rotation axis (5) within the housing (4) to control the degree of impregnation.

11. A method according to claim 7, characterized in that the material to be conveyed is fed from the discharge zone (7) into the reactor (1), the material to be conveyed reacts with the reactants in the reactor (1), and the reaction result in the reactor (1) is influenced by controlling the degree of impregnation of the material to be conveyed.

12. Method according to claim 7, characterized in that the material to be conveyed is compressed between the housing (4) and the screw (6) having at least partially a spiral (9), between the inlet zone (3) and the discharge zone (7), wherein the plug is formed in the discharge zone (7) between the plug tube (8) and the non-spiral region (10) of the screw (6).

13. Method according to claim 12, characterized in that the plug passes first through the annular zone (11) and then through the calibration zone (12).

14. Method according to claim 12, characterized in that the plug passes in the discharge zone (7) through an annular zone (11) formed by the zone of constant inner diameter of the plug tube (8) and the non-helical zone (10) of constant outer diameter of the screw (6).

15. Method according to claim 12, characterized in that the plug passes through a calibration zone (12) after the annular zone (11) in the discharge zone (7), wherein the calibration zone (12) is formed by a region (13) of the plug tube (8) with a reduced inner diameter and by a non-helical region of the screw with a constant outer diameter or by a non-helical region (14) of the screw with a reduced outer diameter, or the calibration zone (12) is formed by a region of the plug tube with a constant or increased inner diameter and by a non-helical region (16) of the screw with an increased outer diameter.

16. Method according to claim 13, characterized in that the impregnation is increased by narrowing the calibration zone (12) or is decreased by widening the calibration zone (12) due to the axial movement of the screw (6).