Slurry impurity separation system

Abstract

The present invention relates to a slurry impurity separation system, comprising: a slurry preparation tower, which is provided with a plurality of stirrers along its circumference; a slurry inlet pipe, located at the upper part of the slurry preparation tower, used to transport the crushed slurry solution to the slurry preparation tower; a slurry outlet pipe, one end of which is located at a predetermined height below the liquid level of the slurry solution, and the other end is located at the lower part of the slurry preparation tower, used to collect the slurry; wherein the predetermined height is h, the liquid level of the slurry solution is H, and h / H=0.6-0.8. The slurry impurity separation system can separate slurry with excellent dispersibility from impurity waste flocculated due to electrostatic adsorption.

Description

Technical Field

[0001] The invention relates to the technical field of waste paper processing, and in particular to a pulp impurity separation system. Background Art

[0002] The world's pulp and papermaking technology is developing in the direction of reducing pollution, saving energy and water resources, and making full use of waste paper fibers. Among them, the production of corrugated paper using waste paper as raw material is the production project chosen by most paper mills.

[0003] In the process of recycling waste paper, it is necessary to remove the residues in the waste paper, such as dust, particles, plastic film and other non-plant fiber impurities. However, there will always be some residual impurities entering the pulp preparation and storage tower along with the waste paper shredding. In the pulp preparation and storage tower, the waste paper pulp after hydraulic shredding becomes fiber. The fiber itself carries a small amount of negative charge. Due to the polarization of water molecules, the negative charge on the fiber surface generates electrostatic effect, which causes the fibers to flocculate due to electrostatic adsorption, and it is not easy to break up, which affects the quality of paper products. Summary of the invention

[0004] The object of the present invention is to provide a slurry impurity separation system, which can separate slurry with excellent dispersibility from impurity wastes flocculated due to electrostatic adsorption.

[0005] To this end, the present invention proposes a slurry impurity separation system, comprising: a slurry preparation tower, which is provided with a plurality of agitators along its circumference; a slurry inlet pipe, which is located at the upper part of the slurry preparation tower and is used to transport the crushed slurry solution to the slurry preparation tower; a slurry outlet pipe, which has one end located at a predetermined height below the liquid level of the slurry solution and the other end located at the lower part of the slurry preparation tower and is used to collect the slurry; wherein the predetermined height is h, the liquid level of the slurry solution is H, and h / H=0.6~0.8.

[0006] According to one aspect of an embodiment of the present invention, the slurry outlet pipe includes a first pipe portion and a second pipe portion arranged at a predetermined angle, and a corrugated pipe connecting the first pipe portion and the second pipe portion, the first pipe portion is arranged to be tapered from top to bottom, and the first pipe portion is also provided with a plurality of sieve holes along its circumference, and the second pipe portion extends outward from the lower part of the slurry preparation tower and is connected to the slurry pump.

[0007] According to one aspect of the embodiments of the present invention, a baffle is disposed in the first pipe portion of the slurry outlet pipe, and the baffle extends radially from the wall portion of the first pipe portion and forms a rotating channel that spirally descends toward the second pipe portion.

[0008] According to one aspect of an embodiment of the present invention, the slurry impurity separation system also includes a lifting mechanism located at the top of the slurry preparation tower, the lifting mechanism includes a traction rope, the traction rope is connected to the first pipe portion of the slurry outlet pipe, and is used to drive the slurry outlet pipe to move up and down as the liquid level of the slurry solution changes.

[0009] According to one aspect of an embodiment of the present invention, the slurry impurity separation system also includes a liquid level sensor and a controller. The liquid level sensor is located at a predetermined position of the slurry preparation tower and is used to sense the liquid level of the slurry solution. The controller is electrically connected to the liquid level sensor and the lifting mechanism, respectively.

[0010] According to one aspect of the embodiment of the present invention, a plurality of sampling interfaces are arranged on the outer peripheral surface of the slurry preparation tower at intervals along the height direction of the slurry preparation tower.

[0011] According to one aspect of the embodiment of the present invention, a liquid level window is further provided on the outer peripheral surface of the slurry preparation tower, and the liquid level window is provided adjacent to the plurality of sampling interfaces.

[0012] According to one aspect of the embodiments of the present invention, the portion of the second pipe portion of the slurry outlet pipe extending to the outside of the slurry preparation tower is arranged in a curved structure.

[0013] According to one aspect of an embodiment of the present invention, a slow flow device is provided at one end of the discharge port of the slurry inlet pipe in the slurry preparation tower. The slow flow device is a tubular structure, and the bottom of the slow flow device is opposite to the discharge port and is spaced apart.

[0014] According to one aspect of the embodiment of the present invention, a conical flow guide and a plurality of slag discharge ports are also provided at the bottom of the flow slowing device.

[0015] According to one aspect of the embodiment of the present invention, the bottom of the stock preparation tower is provided with an inclined surface and a waste material port corresponding to the inclined surface, and a plurality of conical structures are provided on the inclined surface.

[0016] The present invention provides a pulp impurity separation system, which extracts pulp at a predetermined height of the liquid surface of the pulp solution in a pulp preparation tower, and can separate waste impurities flocculated by electrostatic adsorption in the pulp solution from the pulp with excellent dispersibility to be taken, which is beneficial to improving the uniformity of the pulp and improving the quality of paper products. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The features, advantages and technical effects of the exemplary embodiments of the present invention will be described below with reference to the accompanying drawings. In the accompanying drawings, the same components are marked with the same reference numerals. The accompanying drawings are not drawn to scale.

[0018] Figure 1 A schematic structural diagram of a slurry impurity separation system provided according to an embodiment of the present invention is shown;

[0019] Figure 2 Show Figure 1 A schematic diagram of the top view of the slurry impurity separation system shown;

[0020] Figure 3 Show Figure 1 A partial structural schematic diagram of a slurry outlet pipe of a slurry impurity separation system shown;

[0021] Figure 4 Show Figure 1 A schematic diagram of the partial structure of the slurry inlet pipe of the slurry impurity separation system is shown.

[0022] Description of reference numerals:

[0023] 1-slurry preparation tower; 11-sampling interface; 12-liquid level window; 13-inclined surface; 131-conical structure; 14-waste port; 15-agitator;

[0024] 2-slurry inlet pipe; 21-discharge port; 22-slow flow device; 312-sieve hole; 221-conical flow guide; 222-slag discharge port;

[0025] 3-slurry outlet pipe; 31-first pipe portion; 311-blocking piece; 32-second pipe portion;

[0026] 4-lifting mechanism; 41-traction rope;

[0027] 5-Liquid level sensor. DETAILED DESCRIPTION

[0028] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In the detailed description below, many specific details are proposed in order to provide a comprehensive understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by illustrating examples of the present invention. In the drawings and the following description, at least part of the known structures and technologies are not shown in order to avoid unnecessary ambiguity of the present invention; and, for clarity, the size of some structures may be exaggerated. In addition, the features, structures or characteristics described below may be combined in one or more embodiments in any suitable manner.

[0029] The directional words appearing in the following description are all directions shown in the figure, and do not limit the specific structure of the slurry impurity separation system of the present invention. In the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0030] In the process of recycling waste paper, after removing the residues in the waste paper such as dust, particles, plastic film and other non-plant fibers, the waste paper needs to be hydraulically crushed. The crushed pulp enters the pulp preparation tower for storage. In the prior art, the pulp inlet and the pulp outlet are mostly set at the bottom of the pulp preparation tower. The pulp entering the pulp preparation tower from the pulp inlet contains a plurality of fibers. The fibers themselves carry a small amount of negative charge. Due to the polarization of water molecules, the negative charge on the surface of the fibers produces electrostatic effect, which causes the fibers and the fibers and the fine impurities to flocculate due to electrostatic adsorption and deposit to the bottom. The flocculated pulp is difficult to break up because the fibers and impurities are entangled with each other, and cannot be transported to the subsequent process for papermaking.

[0031] The inventors have found in production practice that if the pulp is transported from a high position in a pulp preparation tower and the pulp is extracted from a high position, a pulp with regular fiber arrangement and excellent dispersion performance can be obtained. These pulps are not easy to flocculate and are easy to break up. If these high-quality pulps are used for papermaking, the quality of paper products can be greatly improved. To this end, an embodiment of the present invention provides a pulp impurity separation system. The specific structure of the pulp impurity separation system is described in detail below in conjunction with the accompanying drawings.

[0032] Figure 1 A schematic structural diagram of a slurry impurity separation system according to an embodiment of the present invention is shown. Figure 2 Show Figure 1 The top view structural schematic diagram of the slurry impurity separation system is shown.

[0033] Please also read Figure 1 and Figure 2 An embodiment of the present invention provides a slurry impurity separation system, comprising: a slurry preparation tower 1, a slurry inlet pipe 2 and a slurry outlet pipe 3.

[0034] The stock preparation tower 1 is provided with a plurality of stirrers 15 along its circumference. The stirrers 15 have a relatively low rotation speed and are mainly used to stir and break up the fibers in the slurry to prevent the fibers from flocculating due to electrostatic adsorption.

[0035] The slurry inlet pipe 2 is located at the upper part of the slurry preparation tower 1 and is used to transport the crushed slurry solution to the slurry preparation tower 1 .

[0036] One end of the slurry discharge pipe 3 is located at a predetermined height below the liquid surface of the slurry solution, and the other end is located at the lower part of the slurry preparation tower 1 for collecting slurry.

[0037] The predetermined height is h, the liquid level of the slurry solution is H, and h / H=0.6-0.8.

[0038] One end of the pulp inlet pipe 2 is connected to the crushing system in the previous process, and the other end extends into the pulp preparation tower 1, and is released from the upper part of the pulp preparation tower 1 at a certain flow rate to be transported to the pulp preparation tower 1. The crushed pulp contains fibers of different lengths, which are suspended in the pulp solution.

[0039] One end of the slurry discharge pipe 3 is located at a predetermined height below the liquid level of the slurry solution, and the predetermined height h is located at 0.6 to 0.8 of the total height H of the slurry preparation tower 1. The other end is located at the lower part of the slurry preparation tower 1, and is used to introduce the collected slurry into the next process.

[0040] It is inevitable that some fine impurities will be mixed in the slurry. The fibers in the slurry themselves carry a small amount of negative charge. When these impurities move downward under their own gravity, the negative charge on the fiber surface generates electrostatic effect, causing the impurities and fibers, as well as the fibers and fibers, to gradually flocculate due to electrostatic adsorption and quickly settle to the bottom.

[0041] Since the slurry outlet pipe 3 is close to the liquid surface of the slurry solution, a part of the slurry that has just been dispersed before the slurry flocculates due to the electrostatic adsorption of the fibers can be introduced into the slurry outlet pipe 3 first. The impurities in this part of the slurry automatically sink under the action of its own gravity and are easily dispersed without flocculation, and become high-quality slurry to be transported to the next process.

[0042] A pulp impurity separation system provided in an embodiment of the present invention can extract pulp at a predetermined height h of the liquid surface of the pulp solution in the pulp preparation tower 1, thereby separating waste impurities flocculated by electrostatic adsorption in the pulp solution from the pulp with excellent dispersibility to be extracted, which is beneficial to improving the uniformity of the pulp and improving the quality of paper products.

[0043] Figure 3 Show Figure 1 A schematic diagram of the partial structure of the slurry outlet pipe of the slurry impurity separation system is shown.

[0044] Please read again Figure 1 and Figure 3 The pulp outlet pipe 3 includes a first pipe portion 31 and a second pipe portion 32 which are arranged at a predetermined angle, and a corrugated pipe 33 connecting the first pipe portion 31 and the second pipe portion 32. The first pipe portion 31 is arranged to be gradually reduced from top to bottom, and the first pipe portion 31 is also provided with a plurality of sieve holes 312 along its circumference. The second pipe portion 32 extends outward from the lower part of the pulp preparation tower 1 and is connected to a pulp pump (not shown in the figure).

[0045] Optionally, the predetermined angle between the first tube portion 31 and the second tube portion 32 may be 90°. The first tube portion 31 is tapered from top to bottom and presents a conical tubular structure, which facilitates the introduction of the slurry into the slurry outlet pipe 3. The first tube portion 31 is also provided with a plurality of sieve holes 312 along its circumference, and the plurality of sieve holes 312 can quickly filter out the water in the slurry, filter out the fibers in the slurry, and increase the density of the slurry.

[0046] Optionally, the first pipe part 31 and the second pipe part 32 are made of metal or pipes with greater rigidity, and the corrugated pipe 33 is a retractable plastic part. Since the first pipe part 31 and the second pipe part 32 are arranged at a predetermined angle, the slurry introduced from the first pipe part 31 needs to be reversed and then sucked out from the second pipe part 32, and the corrugated pipe 33 can buffer the slurry at the reversal point to prevent the slurry from being blocked.

[0047] In some embodiments, a baffle 311 is disposed in the first tube portion 31 of the slurry outlet pipe 3 . The baffle 311 extends radially from the wall of the first tube portion 31 and forms a spirally descending rotating channel toward the second tube portion 32 .

[0048] Since the second pipe part 32 is connected to the pulp pump, the pulp slurry with a certain concentration entering the pulp outlet pipe 3 can enter the pulp outlet pipe 3 from the thicker end of the first pipe part 31 at a certain flow rate under the action of negative pressure. Due to the pressure, the pulp slurry enters the stepped spiral baffle 311, so that a closed vortex appears in the part of the slurry flowing therethrough. There is a certain speed difference between the closed vortex and the main pulp flow flowing in the middle, and a strong mass and energy exchange occurs between the main pulp flow and the closed vortex, thereby generating a strong turbulence. There is a large velocity gradient between the turbulences, which generates shear force, breaks the floccules in the slurry, and the slurry dispersed by shear is not easy to flocculate in the process of flowing in the spiral descending channel, thereby improving the uniformity of the slurry.

[0049] As the pulp inlet pipe 2 continuously introduces the crushed pulp into the pulp preparation tower 1, the liquid level of the pulp solution gradually rises. In order to keep the end of the pulp outlet pipe 3 at a predetermined distance from the liquid level, the height of the pulp outlet pipe 3 needs to be adjusted at any time.

[0050] In some embodiments, the slurry impurity separation system also includes a lifting mechanism 4 located at the top of the slurry preparation tower 1, and the lifting mechanism 4 includes a traction rope 41, which is connected to the first pipe portion 31 of the slurry outlet pipe 3 and is used to drive the slurry outlet pipe 3 to move up and down as the liquid level of the slurry solution changes.

[0051] Optionally, the lifting mechanism 4 may be a winch, which drives the pulp outlet pipe 3 to move up and down through a pulley block and a traction rope 41 wound around the pulley block. Since a retractable corrugated tube 33 is provided between the first tube portion 31 and the second tube portion 32, a suitable deformation amount can be reserved for the up and down movement of the first tube portion 31.

[0052] In some embodiments, in order to accurately control the up and down movement of the slurry outlet pipe 3, the slurry impurity separation system also includes a liquid level sensor 5 and a controller. The liquid level sensor 5 is located at a predetermined position of the slurry preparation tower 1 and is used to sense the liquid level of the slurry solution. The controller is electrically connected to the liquid level sensor 5 and the lifting mechanism 4 respectively.

[0053] The liquid level sensor 5 is a pressure sensor for measuring the liquid level. Based on the principle that the static pressure of the measured liquid is proportional to the height of the liquid, an isolated diffused silicon sensitive element or a ceramic capacitor pressure sensitive sensor is used to convert the static pressure into an electrical signal, which is then converted into a standard electrical signal after temperature compensation and linear correction, so that the liquid level of the slurry solution can be sensed.

[0054] The controller can receive the standard electrical signal sent by the liquid level sensor 5 and convert the standard electrical signal into the liquid level height, and control the movement of the lifting mechanism 4 according to the liquid level height so that the first pipe part 31 of the slurry outlet pipe 3 connected to the lifting mechanism 4 is located at a set height, which is convenient for extracting high-quality slurry.

[0055] In some embodiments, a plurality of sampling interfaces 11 are arranged at intervals on the outer peripheral surface of the stock preparation tower 1 along its own height direction. Through the plurality of sampling interfaces 11, slurry samples at corresponding heights can be respectively extracted, and the slurry samples are placed in a storage container. The slurry samples in the storage container are scanned by an image acquisition device to collect a slurry flocculation image of the slurry sample and obtain a streak index corresponding to the slurry flocculation image. The streak index is used to describe the uniformity of the slurry sample. By detecting parameters such as the fiber content, impurity content, and whether flocculation occurs in the slurry solution at each liquid level, the uniformity of the slurry can be quantitatively controlled.

[0056] In some embodiments, a liquid level window 12 is further provided on the outer circumference of the stock preparation tower 1, and the liquid level window 12 is provided adjacent to the plurality of sampling interfaces 11. The liquid level window 12 facilitates the operator to observe the liquid level in the stock preparation tower 1 from outside the stock preparation tower 1, and facilitates controlling the amount of slurry fed into the slurry inlet pipe 2.

[0057] In some embodiments, the second pipe portion 32 of the slurry outlet pipe 3 extending to the outside of the slurry preparation tower 1 is arranged in a curved structure. Figure 1 As shown, the second pipe portion 32 of the slurry outlet pipe 3 extending to the outside of the slurry preparation tower 1 is arranged in a U-shaped curve to further buffer the flow rate of the slurry and prevent the slurry from being quickly sucked out by the slurry pump and flocculating.

[0058] Figure 4 Show Figure 1 A schematic diagram of the partial structure of the slurry inlet pipe of the slurry impurity separation system is shown.

[0059] See also Figure 4 The slurry inlet pipe 2 is located at one end of the discharge port 21 in the slurry preparation tower 1 and is also provided with a slow flow device 22. The slow flow device 22 is a tubular structure, and the bottom of the slow flow device 22 is opposite to the discharge port 21 and is arranged at an interval.

[0060] The bottom of the slow flow device 22 is opposite to the discharge port 21 and is spaced apart to form a flow guide channel. The slurry introduced from the slurry inlet pipe 2 passes through the flow guide channel along the Figure 4 Enter the slow flow device 22 in the direction indicated by the arrow in the middle, and from the top of the slow flow device 22 along Figure 4 The liquid flows out to the stock preparation tower 1 in the direction indicated by the middle arrow.

[0061] Since the slurry inlet pipe 2 is located at the upper part of the slurry preparation tower 1, the slurry introduced from the slurry inlet pipe 2 has a certain spraying pressure and spraying amount. The slow flow device 22 can buffer the pressure and flow rate of the slurry, reduce the surface tension of the slurry and the collision chance of the slurry fibers, reduce the flocculation between the fibers, and make the fibers less likely to entangle.

[0062] In some embodiments, the bottom of the slow flow device 22 is also provided with a conical guide 221 and a plurality of slag discharge ports 222. The conical guide 221 is used to disperse the slurry, prevent the slurry from being blocked in the diversion channel, and reduce the slurry spraying pressure. Optionally, the longitudinal section inclination angle θ of the conical guide 221 is 30°, so that the slurry spraying pressure is not too large to wash away the conical guide 221, nor too small to cause blockage. The slag discharge port 222 is used to discharge impurities deposited in the process of dispersing the slurry to prevent impurities from blocking the diversion channel.

[0063] See again Figure 1 In some embodiments, the bottom of the slurry preparation tower 1 is provided with an inclined surface 13 and a waste port 14 corresponding to the inclined surface 13, and a plurality of conical structures 131 are provided on the inclined surface 13. The conical structures 131 are used to break up the slurry deposited at the bottom, reduce the size of the flocculated slurry blocks as much as possible, and prevent the waste port 14 from being blocked. The waste port 14 is used to discharge the flocculated waste impurities in the slurry solution, which can be discharged into the stirring device for rapid secondary crushing. After crushing, it can enter the slurry preparation tower 1 again through the slurry inlet 2 to improve the utilization rate of the slurry.

[0064] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A slurry impurity separation system, characterized in that: include: A slurry preparation tower (1) is provided with a plurality of stirrers (15) along its circumference; A slurry inlet pipe (2), located at the upper part of the slurry preparation tower (1), used for conveying the slurry solution after the crushing to the slurry preparation tower (1); A slurry outlet pipe (3), one end of which is located at a predetermined height below the liquid surface of the slurry solution, and the other end of which is located at the lower part of the slurry preparation tower (1), for collecting slurry; a slurry inlet pipe (2) is also provided with a slow flow device (22) at one end of the discharge port (21) in the slurry preparation tower (1), the slow flow device (22) being a tubular structure, the bottom of the slow flow device (22) being opposite to the discharge port (21) and being arranged at a distance; Wherein, the predetermined height is h, the liquid level of the slurry solution is H, and h / H=0.6-0.8; The pulp outlet pipe (3) comprises a first pipe portion (31) and a second pipe portion (32) arranged at a predetermined angle, and a corrugated pipe (33) connecting the first pipe portion (31) and the second pipe portion (32); the first pipe portion (31) is arranged to be gradually tapered from top to bottom, and the first pipe portion (31) is also provided with a plurality of sieve holes (312) along its circumference; the second pipe portion (32) extends outward from the lower part of the pulp preparation tower (1) and is connected to a pulp pump.

2. The slurry impurity separation system according to claim 1, characterized in that: A baffle (311) is arranged inside the first pipe portion (31) of the slurry outlet pipe (3); the baffle (311) extends radially from the wall portion of the first pipe portion (31) and forms a spirally descending rotating channel toward the second pipe portion (32).

3. The slurry impurity separation system according to claim 1, characterized in that: The slurry impurity separation system also includes a lifting mechanism (4) located at the top of the slurry preparation tower (1), and the lifting mechanism (4) includes a traction rope (41). The traction rope (41) is connected to the first pipe portion (31) of the slurry outlet pipe (3) and is used to drive the slurry outlet pipe (3) to move up and down as the liquid level of the slurry solution changes.

4. The slurry impurity separation system according to claim 3, characterized in that: The slurry impurity separation system further comprises a liquid level sensor (5) and a controller. The liquid level sensor (5) is located at a predetermined position of the slurry preparation tower (1) and is used to sense the liquid level height of the slurry solution. The controller is electrically connected to the liquid level sensor (5) and the lifting mechanism (4), respectively.

5. The slurry impurity separation system according to claim 3, characterized in that: A plurality of sampling interfaces (11) are arranged at intervals on the outer peripheral surface of the slurry preparation tower (1) along its height direction.

6. The slurry impurity separation system according to claim 5, characterized in that: A liquid level window (12) is also provided on the outer peripheral surface of the slurry preparation tower (1), and the liquid level window (12) is arranged adjacent to the plurality of sampling interfaces (11).

7. The slurry impurity separation system according to claim 1, characterized in that: The portion of the second pipe portion (32) of the slurry outlet pipe (3) extending to the outside of the slurry preparation tower (1) is arranged in a curved structure.

8. The slurry impurity separation system according to claim 1, characterized in that: The bottom of the flow slowing device (22) is also provided with a conical flow guide (221) and a plurality of slag discharge ports (222).

9. The slurry impurity separation system according to claim 1, characterized in that: The bottom of the stock preparation tower (1) is provided with an inclined surface (13) and a waste material port (14) corresponding to the inclined surface (13), and a plurality of conical structures (131) are provided on the inclined surface (13).

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