Mixing device for paper pulp

Abstract

The application provides a mixing device for papermaking pulp, which comprises a pulp container, a shunt pipeline and a plurality of nozzles. The pulp container is internally provided with a containing space for containing papermaking pulp and medicine. The shunt pipeline is arranged at least partially around the pulp container and is connected with a medicine feeding pipeline. The shunt pipeline is provided with a plurality of branch pipes, and the end of each branch pipe is provided with a nozzle. The nozzle is fixedly arranged on the outer sidewall of the pulp container. The discharge port of each nozzle is in communication with the containing space of the pulp container and is used for spraying medicine into the containing space of the pulp container. The mixing device for papermaking pulp provided by the application adopts a multi-nozzle cooperative spraying scheme arranged in a ring shape, greatly increases the two-phase contact area, and promotes micro-mixing through the kinetic energy of the spraying flow, so that rapid and uniform dispersion is achieved.

Description

Technical Field

[0001] This application relates to the technical field of papermaking equipment, specifically to a mixing device for papermaking pulp. Background Technology

[0002] In the pulp preparation process of the chemimechanical pulping field, the uniform mixing of chemicals (hydrogen peroxide, sodium hydroxide, chelating agents, stabilizers, etc.) with solid materials (such as pulp) is a key step to ensure product quality, reaction efficiency and process stability.

[0003] Currently, the widely used hybrid methods mainly include: (1) Direct pipeline injection method: The chemicals are directly pumped into the mixing tank or main pipeline through a single pipeline and mixed by fluid turbulence. This method is simple, but the mixing effect is weak and problems such as local overconcentration and uneven dispersion of chemicals are easy to occur, resulting in incomplete reaction, unstable effect and increased chemical consumption.

[0004] (2) Mechanical stirring method: A mechanical stirrer is installed in the mixing tank, and the mixing is forced by the rotation of the blades. This method improves the mixing effect, but it has problems such as complex equipment structure, high energy consumption, easy wear of stirring parts, high maintenance cost, and easy to generate stirring dead zone or shear damage to material structure for high viscosity slurry.

[0005] (3) Static mixer method: Static mixing elements are installed in the pipeline to divide and recombine the fluid. This method has no moving parts, but it still has disadvantages such as insufficient mixing intensity, easy clogging, and large pressure drop. Therefore, developing a mixing device with simple structure, high mixing efficiency and uniformity, strong adaptability and reliable operation has important industrial application value. Utility Model Content

[0006] This application provides a mixing device for papermaking pulp. The mixing device includes a pulp container, a distribution pipe, and multiple nozzles. The pulp container has an internal receiving space for containing papermaking pulp and chemicals. The distribution pipe is arranged at least partially around the pulp container and is connected to a chemical dosing pipe. The distribution pipe has multiple branch pipes, and each branch pipe has a nozzle at its end. The nozzles are fixed to the outer wall of the pulp container, and the outlet of each nozzle is connected to the receiving space of the pulp container for spraying chemicals into the receiving space of the pulp container.

[0007] In some alternative embodiments, the slurry container includes a bottom wall, a top wall, and a side wall connecting the bottom wall and the top wall, with the plurality of nozzles respectively fixed to at least one of the side wall and the top wall.

[0008] In some alternative embodiments, a plurality of the nozzles are respectively fixed to the sidewall of the slurry container and arranged circumferentially along the sidewall.

[0009] In some alternative embodiments, the plurality of nozzles are positioned at the same height on the sidewall of the slurry container.

[0010] In some alternative embodiments, the plurality of nozzles are positioned at a height of one-half or more of the overall height of the slurry container on the sidewall of the slurry container.

[0011] In some alternative embodiments, the plurality of nozzles are positioned at a height of two-thirds of the overall height of the slurry container on the sidewall of the slurry container.

[0012] In some alternative embodiments, the dosing line is equipped with a control valve.

[0013] In some alternative embodiments, the nozzle is connected to the branch pipe via a ball joint or threaded sleeve, thereby allowing the nozzle to adjust the spray angle.

[0014] In some alternative embodiments, the nozzle sprays at a horizontal or downward angle.

[0015] In some alternative embodiments, the nozzle is selected from any one or more of a spiral nozzle, a fan nozzle, or a solid cone nozzle, and the nozzle material includes stainless steel, ceramic, or engineering plastic.

[0016] The paper pulp mixing device provided in this application adopts a multi-nozzle coordinated injection scheme arranged in a ring. Each nozzle is an independent atomizing or injection unit. Chemicals are uniformly distributed to each nozzle through a distributor and a ring pipe, and then simultaneously injected into the pulp at a certain pressure and angle. This design instantly forms multiple uniformly distributed chemical addition points in the mixing area, greatly increasing the contact area between the two phases, and promoting micro-mixing through the kinetic energy of the jet flow, thereby achieving rapid and uniform dispersion. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a partial structural schematic diagram of an embodiment of the pulp system of this application; Figure 2This is a top view schematic diagram of an embodiment of the paper pulp mixing apparatus of this application; Figure 3 yes Figure 2 A side view of the mixing device in the embodiment; Figure 4 This is a top view schematic diagram of another embodiment of the paper pulp mixing apparatus of this application; Figure 5 yes Figure 4 A side view of the mixing device in the embodiment. Detailed Implementation

[0019] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are for illustrative purposes only and do not limit the scope of the application. Similarly, the following embodiments are only some, not all, embodiments of the present application, and all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present application.

[0020] The terms "first," "second," and "third" used in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movement of components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly. The terms "comprising" and "having," and any variations thereof, in the embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to these processes, methods, products, or devices.

[0021] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] Please see Figure 1 , Figure 1 This is a partial structural diagram of an embodiment of the pulp system of this application. The pulp system 10a may include, but is not limited to, the following structures: a mixing device 10, a mixer 20, a first conveying device 30, a chemical reagent 40, a second conveying device 50, and a bleaching tower 60. The pulp is first mixed in the mixer 20, and then conveyed to the mixing device 10 via the first conveying device 30. A chemical reagent 40 (including hydrogen peroxide, sodium hydroxide, chelating agents, stabilizers, etc., not specifically limited here) is added to the mixing device 10. The chemical reagent 40 is mixed in the pulp container 10 (the detailed structure of which will be described later) (300 in the figure indicates a nozzle, and 3000 indicates an aerosol-like chemical reagent sprayed from the nozzle). Then, it is conveyed to the bleaching tower 60 for storage using the second conveying device 50. In this embodiment, the main modification is to the pulp mixing device 10.

[0023] Please refer to the following: Figure 2 and Figure 3 , Figure 2 This is a top view schematic diagram of an embodiment of the paper pulp mixing apparatus of this application. Figure 3 yes Figure 2 The side view of the mixing device in the embodiment shows that the mixing device 10 includes a slurry container 100, a diversion pipe 200, and multiple nozzles 300. The slurry container 100 has a receiving space 1000 for holding papermaking slurry and chemicals. The diversion pipe 200 is at least partially arranged around the slurry container 100 and is connected to a dosing pipe 400. The dosing pipe 400 is used to connect to external dosing equipment (such as a dosing pump or chemical storage device) and allow chemicals to flow in. The dosing pipe 400 is equipped with a control valve 410 for controlling the opening and closing of the chemical solution and the flow rate of the chemical solution.

[0024] The distribution pipe 200 has multiple branch pipes 210, each with a nozzle 300 at its end. One end of the main inlet pipe (dosing pipe 400) connects to an external chemical delivery pipeline; the other end connects to the distribution pipe 200, which can be a ring structure and horizontally arranged to evenly distribute incoming chemicals to each branch pipe 210. The diameter of the distribution pipe 200 needs to be calculated to ensure that the fluid pressure loss reaching each nozzle 300 is basically consistent, thereby achieving equal flow rate distribution, which is crucial for achieving uniform mixing.

[0025] The nozzle is fixed to the outer wall of the slurry container 100, which can be achieved by bonding, welding, or detachable sealing connection. The outlet of each nozzle 300 is connected to the receiving space 1000 of the slurry container 100 and is used to spray the medicine into the receiving space 1000 of the slurry container 100.

[0026] Optionally, the slurry container 100 in this embodiment includes a bottom wall 110, a top wall 120, and a side wall 130 connecting the bottom wall 110 and the top wall 120. The slurry container 100 is generally a columnar structure, such as a cylinder or a cuboid. A plurality of nozzles 300 are respectively fixed to at least one of the side wall 130 and the top wall 120.

[0027] Optionally, in this embodiment, multiple nozzles 300 (not limited to the eight shown in the figure, but may be other numbers) are fixed to the side wall 130 and arranged around the circumference of the side wall 130. The multiple nozzles are positioned at the same height on the side wall 130 of the slurry container 100. This design structure is intended to allow the liquid sprayed from the multiple nozzles 300 to collide with each other (forming a cross-jet flow field), resulting in more uniform mixing.

[0028] Optionally, in this embodiment, the multiple nozzles 300 are positioned at a height H1 on the side wall 130 of the pulp container 100 within a range of one-half or more of the overall height H of the pulp container 100. Specifically, the multiple nozzles can be positioned at a height H1 on the side wall 130 of the pulp container 100 at approximately two-thirds of the overall height H of the pulp container 100. This height design does not affect the inflow of pulp from the top, while the bottom height (two-thirds of the height H) allows for more mixing space and falling time for the sprayed liquid.

[0029] Optionally, in this embodiment, the nozzle 300 and the branch pipe 210 are connected by a ball joint or a threaded sleeve (not shown in the figure), thereby making the nozzle 300 adjustable in spray angle, allowing the spray angle to be adjusted within a certain range (e.g., 0-45° tilt angle), which enhances the adaptability of the device. The rotating connection structure between the nozzle 300 and the branch pipe 210 via a ball joint or a threaded sleeve (not shown in the figure) is within the understanding of those skilled in the art and will not be described in detail here.

[0030] Optionally, in this embodiment, the spray angle of nozzle 300 is horizontal or diagonally downward. This ensures that the sprayed liquid can collide and cross each other, while avoiding upward spraying to prevent it from affecting the wallpaper paste on the ceiling. Figure 2 The number 121 indicates the pulp inlet.

[0031] The nozzle 300 is selected from one or more of the following: a spiral nozzle, a fan nozzle, or a solid cone nozzle (all nozzles are conventional structures and can be purchased commercially). The material of the nozzle 300 is selected according to the properties of the chemical. Specifically, the material of the nozzle 300 can include stainless steel, ceramic, or engineering plastics to ensure corrosion resistance and wear resistance. The internal structure design of the nozzle 300 ensures that a uniform and stable liquid film or droplet group can be formed when the liquid is sprayed out.

[0032] During operation, the chemical solution is pumped into the main inlet pipe (dosing line 400) of the mixing device 10 in this embodiment, evenly distributed to the branch lines 200, and finally sprayed simultaneously from multiple circumferentially distributed nozzles 300. The sprayed chemicals form multiple fine jets (or atomized droplets, depending on the nozzle type and pressure). These jets enter the slurry bulk from different directions, generating strong shear and turbulence at the jet boundary layer, which promotes thorough mixing of the chemicals with the surrounding slurry in a very short time and distance. By selecting nozzles with different spray angles, adjusting the spray pressure, or adjusting the installation angle, the flow field morphology can be optimized to adapt to slurries with different viscosities, densities, and flow rates, achieving the best mixing effect while avoiding excessive shear damage to the slurry.

[0033] The paper pulp mixing device provided in this application adopts a multi-nozzle coordinated injection scheme arranged in a ring. Each nozzle is an independent atomizing or injection unit. Chemicals are uniformly distributed to each nozzle through a distributor and a ring pipe, and then simultaneously injected into the pulp at a certain pressure and angle. This design instantly forms multiple uniformly distributed chemical addition points in the mixing area, greatly increasing the contact area between the two phases, and promoting micro-mixing through the kinetic energy of the jet flow, thereby achieving rapid and uniform dispersion.

[0034] Please refer to the following: Figure 4 and Figure 5 , Figure 4 This is a top view schematic diagram of another embodiment of the paper pulp mixing apparatus of this application. Figure 5 yes Figure 4 The side view of the mixing device in this embodiment differs from the previous embodiment in that the mixing device in this embodiment also has a diversion pipe 200 and a nozzle 300 on the top wall 120 of the slurry container 100, which can make more drug spray points and mix more evenly.

[0035] The pulp mixing device in this application embodiment can be directly welded or flanged and installed on the top cover, side wall or pipe of the existing pulp container. It requires almost no large-scale modification of the existing equipment, is easy to install, and has strong applicability.

[0036] In a specific practical application example (for low-viscosity slurries): During the mixing of the slurry and chemicals, six fan-shaped stainless steel nozzles were used. A 50mm diameter branch line 200 was used, and the nozzles 300 were mounted on the upper-middle side wall of the slurry container 100 (or only the nozzles on the side wall were activated). The nozzles 300 were horizontally mounted, and the operating pressure was 0.3 MPa. Results showed that mixing time was reduced by 40%, and chemical usage was reduced by 5%.

[0037] In another specific practical application (for high-viscosity slurries): During the mixing of the slurry and chemicals, eight fan-shaped stainless steel nozzles were used, with a 50mm diameter branch line 200. The nozzles 300 were mounted on top of the slurry container 100 (or simply the nozzles on the top wall were activated), and were installed vertically downwards. The operating pressure was 0.6 MPa. Results showed that mixing time was reduced by 30%, and chemical usage was reduced by 11%.

[0038] Compared with the prior art, the pulp mixing device in the embodiments of this application has the following significant advantages and beneficial effects: 1. Significantly improved mixing efficiency and uniformity: The multi-nozzle annular arrangement creates a uniform chemical dosing surface in space, completely avoiding the problem of localized concentration unevenness caused by single-point dosing. The strong turbulence generated by the jet stream enables rapid mixing of chemicals and slurry at the microscale, reducing mixing time by 30%-50% compared to traditional methods, and improving mixing uniformity (measured by the coefficient of variation of concentration, CV) by more than 40%.

[0039] 2. Stable mixing quality and high product consistency: Uniform mixing ensures the sufficiency and consistency of chemical reactions or physical processes, improves the quality stability of the final product, reduces batch-to-batch differences and quality fluctuations caused by uneven mixing, reduces dust in chemimechanical pulping by 10%, and significantly reduces color difference.

[0040] 3. Reduced energy consumption and operating costs: This device relies on fluid pressure energy for mixing, eliminating the need for additional mechanical stirring power, resulting in significantly lower energy consumption compared to mechanical stirring methods. Furthermore, the absence of moving parts avoids mechanical wear and the maintenance costs associated with regularly replacing stirrers, seals, etc., leading to a longer service life.

[0041] 4. High operational flexibility and wide adaptability: By simply adjusting the injection pressure, angle or changing the nozzle type, it can flexibly adapt to the mixing requirements of materials with different viscosities, densities and throughput. One set of equipment can meet a variety of working conditions and has strong versatility.

[0042] 5. Prevent clogging and scaling: Proper nozzle selection and jet kinetic energy help keep the nozzle itself and the mixing area clean, reducing the risk of chemical deposits and scaling on the equipment surface and lowering maintenance frequency.

[0043] 6. Simple structure, easy implementation and promotion: The device has a simple structure, mainly composed of standard pipe fittings and nozzles. The manufacturing process is mature and the cost is low. It is easy to install and is particularly suitable for technical transformation of existing equipment with poor mixing effect. It is easy to promote and apply in the industry.

[0044] 7. Environmentally Friendly: Efficient mixing reduces ineffective chemical consumption and waste, while avoiding adverse reactions or byproduct formation that may result from uneven mixing. Hydrogen peroxide consumption is reduced by 5% when producing 70% ISO whiteness social cardboard slurry; and by 11% when producing 77% ISO whiteness food cardboard slurry.

[0045] The paper pulp mixing device in this application aims to overcome the aforementioned defects of the prior art and solve the technical problems of uneven mixing of chemicals and pulp, low efficiency, easy equipment damage, or unstable operation. The main objectives of this application include: (1) Provide a mixing device with high mixing efficiency and good uniformity to avoid excessively high or low local concentrations of chemicals; (2) Provide a mixing device with simple structure, no moving parts, low wear resistance and low maintenance cost; (3) Provide a mixing device that is widely adaptable and can be adjusted by parameters to be suitable for materials with different viscosities and flow rates; (4) Provide a hybrid tool that is easy to manufacture, easy to install, and can be widely used in the transformation of existing production lines or the construction of new equipment.

[0046] The above description is only a part of the embodiments of this application and does not limit the scope of protection of this application. Any equivalent device or equivalent process transformation made based on the content of this application specification and drawings, or direct or indirect application in other related technical fields, are similarly included in the patent protection scope of this application.

Claims

1. A mixing device for papermaking pulp, characterized in that, The mixing device includes a pulp container, a distribution pipe, and multiple nozzles. The pulp container has an internal space for holding paper pulp and chemicals. The distribution pipe is arranged at least partially around the pulp container and is connected to a chemical dosing pipe. The distribution pipe has multiple branches, each with a nozzle at its end. The nozzles are fixed to the outer wall of the pulp container, and the outlet of each nozzle is connected to the storage space of the pulp container for spraying chemicals into the storage space of the pulp container.

2. The mixing device according to claim 1, characterized in that, The slurry container includes a bottom wall, a top wall, and a side wall connecting the bottom wall and the top wall, with the plurality of nozzles respectively fixed at at least one of the side wall and the top wall.

3. The mixing device according to claim 2, characterized in that, The plurality of nozzles are respectively fixed to the side wall of the slurry container and arranged circumferentially along the side wall.

4. The mixing apparatus according to claim 3, characterized in that, The multiple nozzles are positioned at the same height on the side wall of the slurry container.

5. The mixing apparatus according to claim 4, characterized in that, The nozzles are positioned at a height of one-half or more of the overall height of the slurry container on the side wall of the slurry container.

6. The mixing apparatus according to claim 4, characterized in that, The nozzles are positioned at a height of two-thirds of the overall height of the slurry container on the side wall of the slurry container.

7. The mixing apparatus according to claim 1, characterized in that, The dosing pipeline is equipped with a control valve.

8. The mixing apparatus according to claim 1, characterized in that, The nozzle is connected to the branch pipe via a ball joint or a threaded sleeve, thereby allowing the nozzle to adjust the spray angle.

9. The mixing apparatus according to claim 8, characterized in that, The nozzle's spray angle is horizontal or downward.

10. The mixing apparatus according to claim 1, characterized in that, The nozzle is selected from any one or more of spiral nozzles, fan nozzles or solid cone nozzles, and the material of the nozzle includes stainless steel, ceramic or engineering plastic.

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