Regenerated kraft paper and production device thereof

Abstract

The invention belongs to the technical field of sewage treatment, and particularly relates to regenerated kraft paper and a production device thereof.The regenerated kraft paper comprises a three-layer composite forming paper machine, a collecting pipeline is installed at the bottom of the three-layer composite forming paper machine, one end of the collecting pipeline is connected with a sewage pump, and the drainage end of the sewage pump is connected with a sewage conveying pipe; a settling tank is arranged on one side of the three-layer composite forming paper machine, bubble stones are installed in a flocculation cylinder, gas is guided into the bubble stones along an aeration pipe, a large number of bubbles are generated in sewage, the bubbles are used for impacting the sewage to promote combination of the sewage and a flocculating agent, and it is prevented that flocs are easily scattered in the mixing process in a traditional stirring mode, so that the mixing efficiency is improved. Then the sewage mixed with the flocculating agent is slowly guided into the water body stored in the settling tank along the buffer pipe and the buffer cover, the static water body in the settling tank enables the sewage to be quickly calm under the action of buffer and viscous resistance, the situation that the impurity flocculation effect is affected by water body flowing is avoided, and the flocculation efficiency of tiny impurities in the sewage is greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a recycled kraft paper and its production apparatus. Background Technology

[0002] Recycled kraft paper is made primarily from recycled pulp derived from recycled waste paper, with recycled pulp typically accounting for over 80% of its production. By replacing virgin wood pulp, this product reduces forest resource consumption; however, its environmental benefits require comprehensive evaluation in conjunction with pollution control levels during production. Compared to 100% wood pulp kraft paper, its physical properties, such as burst strength and folding endurance, are relatively weaker, making it suitable for packaging applications such as cartons and tote bags where high strength is not required.

[0003] The production of recycled kraft paper generates a large amount of wastewater. To avoid environmental pollution, wastewater typically requires treatment through filtration, flocculation, and sedimentation before discharge. Existing treatment equipment adds flocculant to the flocculation tank and then uses an agitator to stir the water, ensuring even distribution and improving flocculation efficiency. However, during stirring, the agitator may break up pre-flocculated flocs. Furthermore, when the agitator stops, the stirred wastewater retains some fluidity due to inertia. This fluidity prevents the wastewater from settling quickly, requiring a settling period before flocculation begins. The fluidity of the wastewater hinders floc aggregation, negatively impacting the flocculation of small impurities. Summary of the Invention

[0004] The purpose of this invention is to provide a simple and rationally designed recycled kraft paper and its production apparatus in order to solve the above-mentioned problems.

[0005] The present invention achieves the above objectives through the following technical solutions: A recycled kraft paper production apparatus includes a three-layer composite forming paper machine. A collection pipe is installed at the bottom of the three-layer composite forming paper machine, with a sewage pump connected to one end of the collection pipe. A sewage conveying pipe is connected to the drainage end of the sewage pump. A sedimentation tank is installed on one side of the three-layer composite forming paper machine. A filter structure is installed on the top of the sedimentation tank via a support base. The bottom end of the filter structure is connected to the inside of the sedimentation tank via a manifold. A drive component for rotating the filter structure is installed at one end of the support base. A conveying component for discharging filter residue is installed on the filter structure. An air extraction device is connected to one end of the conveying component, and an exhaust pipe is connected to the other end of the conveying component. A flocculation cylinder is installed inside the sedimentation tank. The top of the flocculation cylinder is fixedly connected to the bottom end of the manifold via a connecting pipe. A flocculant addition component is installed around the top of the flocculation cylinder. Air bubbles are fixedly installed on the bottom wall of the inner cavity of the flocculation cylinder, and an aeration pipe is connected to the air bubbles. The bottom end of the exhaust pipe is fixedly connected to the aeration pipe. The bottom of the flocculation cylinder is connected to a buffer tube with a spiral structure. A buffer cover is fitted on the outside of the buffer tube. The top of the buffer cover is fixedly connected to the outer wall of the buffer tube. An overflow pipe is installed on the side wall of the sedimentation tank between the bottom of the buffer tube and the bottom of the buffer cover.

[0006] As a further optimization of the present invention, the bottom of the sedimentation tank has a funnel-shaped structure, a support leg is fixedly installed on the bottom side wall of the sedimentation tank, a drain pipe is connected to the bottom of the sedimentation tank, a valve is installed at the connection between the drain pipe and the sedimentation tank, and a flow stabilizing ring is fixedly connected to the inner wall of the sedimentation tank above the drain pipe.

[0007] As a further optimization of the present invention, the filtration structure includes a sewage tank fixedly installed on the top of the support base. A sealing end cap is fixedly connected to one end of the sewage tank. A centrifuge cylinder is installed inside the sewage tank. A filter hole is opened on the side wall of the centrifuge cylinder. One end of the centrifuge cylinder is rotatably and sealed inside the sealing end cap. A water inlet hole is opened at the other end of the centrifuge cylinder. A first flow guide shroud is rotatably sleeved on the centrifuge cylinder around the water inlet hole. A water inlet pipe is connected to the first flow guide shroud. The top end of the water inlet pipe penetrates the top wall of the sewage tank and is fixedly connected to the sewage tank. The end of the sewage conveying pipe away from the sewage pump is connected to the water inlet pipe. A manifold is installed on the bottom wall of the middle section of the sewage tank.

[0008] As a further optimization of the present invention, a transmission pipe is fixedly connected to the end of the centrifuge tube away from the first guide shroud. The transmission pipe passes through the end side wall of the sewage tank and is rotatably connected to the sewage tank. The drive assembly includes a motor fixedly connected to the support base. An upper pulley and a lower pulley are respectively installed on the end of the transmission pipe located outside the sewage tank and the middle section of the motor output end. The upper pulley and the lower pulley are connected by a belt ring.

[0009] As a further optimization of the present invention, the material conveying assembly includes an air duct installed inside the centrifuge cylinder and coaxially arranged with the centrifuge cylinder. One end of the air duct passes through a sealing end cap and is fixedly connected to the sealing end cap. A spiral plate is fixedly connected to the outer surface of the air duct. An exhaust chamber communicating with the inside of the air duct is opened in the spiral plate. A slag discharge pipe is fixedly connected to the sealing end cap below the air duct. The exhaust pipe is installed on the end of the air duct near the slag discharge pipe.

[0010] As a further optimization of the present invention, the air extraction device includes an air collection hood sleeved on the output end of the motor, the bottom of the air collection hood being fixedly connected to a support base, a fan blade being fixedly connected to a section of the motor output end located inside the air collection hood, and an air delivery pipe being connected to the top of the air collection hood, with the top end of the air delivery pipe being rotatably connected to a transmission pipe.

[0011] As a further optimization of the present invention, the flocculant addition component includes a second guide shroud fixedly sleeved on the periphery of the top of the flocculation cylinder. The second guide shroud is equipped with a plurality of nozzles that communicate with the inside of the flocculation cylinder. The plurality of nozzles are distributed in a ring at equal intervals. A flocculant addition pipe is connected to one side of the outer wall of the second guide shroud. The end of the flocculant addition pipe away from the second guide shroud passes through the side wall of the sedimentation tank and is fixedly connected to the sedimentation tank.

[0012] As a further optimization of the present invention, a ladder is vertically installed on the outer wall of the sedimentation tank, a protective frame is fixedly connected to the outer side of the top of the ladder, and a maintenance walkway fixedly connected to the protective frame is provided on the top of the sedimentation tank.

[0013] A type of recycled kraft paper comprises, from top to bottom, a surface layer, a core layer, and a bottom layer, wherein the surface layer, core layer, and bottom layer are integrally formed into a single structure through a wet papermaking process; the pulp of the surface layer consists of 30%–50% wood pulp and 50%–70% domestic waste OCC medium fiber pulp, the pulp of the core layer consists of 40%–50% domestic waste OCC long fiber pulp, 40%–50% domestic waste OCC short fiber pulp, and %–% recycled waste pulp, and the pulp of the bottom layer consists of 40%–50% domestic waste OCC long fiber pulp, 40%–50% domestic waste OCC short fiber pulp, and 10%–20% recycled waste pulp; the wood pulp is one or more mixtures of unbleached softwood pulp, unbleached eucalyptus pulp, and roll substitute wood pulp, and the weight of the recycled kraft paper is 95–210 g / m².

[0014] The beneficial effects of this invention are as follows: 1. By installing air stones inside the flocculation cylinder and introducing gas into the air stones through the aeration pipe, a large number of air bubbles are generated in the wastewater. These air bubbles impact the wastewater, promoting the combination of wastewater and flocculant. This prevents the flocs from being easily dispersed during the mixing process in traditional stirring methods. Then, the wastewater mixed with flocculant is slowly introduced into the water stored in the sedimentation tank through the buffer pipe and buffer cover. The still water in the sedimentation tank quickly calms the wastewater under the action of buffering and viscous resistance, avoiding the impact of water flow on the flocculation effect of impurities, and greatly improving the flocculation efficiency of small impurities in the wastewater.

[0015] 2. The centrifuge drum driven by the motor generates centrifugal force, which dehydrates large particles of impurities retained in the centrifuge drum, reducing their mass. At the same time, since one end of the air duct with spiral plates installed on the periphery is fixed to the wastewater tank through a sealed end cap, when the centrifuge drum rotates, the spiral plates can work with the air duct to discharge the dehydrated large particles of impurities through the slag discharge pipe, which is conducive to the collection and treatment of large particles of impurities.

[0016] 3. While the motor drives the centrifuge drum to rotate, it can also drive the fan blades to rotate at high speed in the air collection hood and generate flowing air. Before being delivered to the air stone, the flowing air passes through the inside of the air duct. The spiral plate has an exhaust chamber that communicates with the inner cavity of the air duct, so that the air flows in a spiral after entering the air duct. The spiral flow of air impacts the spiral plate, causing the spiral plate to vibrate and shake off large particles of impurities attached to the spiral plate, greatly reducing the residue of large particles of impurities in the centrifuge drum. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of one side of the overall structure of the present invention; Figure 2 This is a schematic diagram of the other side of the overall structure of the present invention; Figure 3 This is the present invention. Figure 2 A schematic diagram of the cross-sectional structure; Figure 4 This is a schematic diagram of the connection structure of the sewage tank, support base, and manifold of the present invention; Figure 5 This is a schematic diagram of the installation position of the centrifuge tube of the present invention; Figure 6 This is a schematic diagram of the transmission structure between the centrifuge cylinder and the motor of the present invention; Figure 7 This is a schematic diagram of the connection structure of the air duct, spiral plate and sealing end cap of the present invention; Figure 8 This is a schematic diagram of the internal structure of the sedimentation tank of the present invention; Figure 9 This is a schematic diagram showing the connection between the flocculant addition pipe, aeration pipe, buffer cover, and flocculation cylinder of the present invention. Figure 10 This is a schematic diagram of the installation position of the bubble stone of the present invention; Figure 11 This is a schematic diagram showing the positions of the top layer, core layer, and bottom layer of the present invention.

[0018] In the diagram: 001, Three-layer composite papermaking machine; 002, Collection pipe; 003, Sewage pump; 004, Sewage conveying pipe; 101, Sedimentation tank; 102, Support leg; 103, Sewage discharge pipe; 104, Valve; 105, Flow stabilizer ring; 201, Support base; 202, Sewage tank; 203, Sealing end cap; 204, Centrifuge cylinder; 205, Filter hole; 206, Water inlet; 207, First guide shroud; 208, Water inlet pipe; 209, Manifold; 301, Transmission pipe; 302, Motor; 303, Upper pulley; 304, Lower pulley; 305, Leather... 401. Air duct; 402. Spiral plate; 403. Slag discharge pipe; 501. Gas collection hood; 502. Fan blade; 503. Gas transmission pipeline; 504. Exhaust chamber; 505. Exhaust pipe; 601. Flocculation cylinder; 602. Connecting pipe; 603. Second guide hood; 604. Nozzle; 605. Flocculant addition pipe; 606. Air stone; 607. Aeration pipe; 701. Buffer pipe; 702. Buffer cover; 703. Overflow pipe; 801. Ladder; 802. Protective frame; 803. Maintenance walkway; 901. Surface layer; 902. Core layer; 903. Bottom layer. Detailed Implementation

[0019] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0020] Examples, such as Figures 1-3 As shown, a recycled kraft paper production device includes a three-layer composite forming paper machine 001 (the three-layer composite forming paper machine 001 is prior art and will not be described in detail here). The bottom of the three-layer composite forming paper machine 001 is equipped with a collection pipe 002 for collecting sewage. The inner diameter of the collection pipe 002 gradually decreases from one end to the other. The end of the collection pipe 002 with the smaller inner diameter is connected to a sewage pump 003. The drain end of the sewage pump 003 is connected to a sewage conveying pipe 004. When the sewage pump 003 is started, the sewage collected in the collection pipe 002 can be pumped along the sewage conveying pipe 004.

[0021] A sedimentation tank 101 is provided on one side of the three-layer composite forming paper machine 001. The bottom of the sedimentation tank 101 has a funnel-shaped structure. Support legs 102 are fixedly installed on the bottom side wall of the sedimentation tank 101. A sewage pipe 103 is connected to the bottom of the sedimentation tank 101. A valve 104 is installed at the connection between the sewage pipe 103 and the sedimentation tank 101. The sedimentation tank 101 is used to settle the sediment in the sewage. When a large amount of sediment accumulates at the bottom of the sedimentation tank 101, the valve 104 can be opened to discharge the sediment through the sewage pipe 103. A flow stabilizing ring 105 is fixedly connected to the inner wall of the sedimentation tank 101 above the sewage pipe 103. The height of the outer ring of the upper surface of the flow stabilizing ring 105 gradually decreases from the height of the inner ring to form a downward inclined surface, so that the sediment can slide down the inclined surface into the sedimentation tank 101 below the flow stabilizing ring 105 for storage. At the same time, the flow stabilizing ring 105 can stabilize the water flow at the bottom of the sedimentation tank 101 and avoid the sediment from being disturbed by the water flow and being stirred up again.

[0022] like Figures 1-2 and Figures 5-6 As shown, a support base 201 is fixedly installed on the top of the sedimentation tank 101. A wastewater tank 202 is fixedly connected to the support base 201. A sealing end cap 203 is fixedly connected to one end of the wastewater tank 202. A centrifuge cylinder 204 is installed inside the wastewater tank 202. A filter hole 205 is opened on the side wall of the centrifuge cylinder 204. Large particulate impurities in the wastewater are initially filtered through the filter hole 205. One end of the centrifuge cylinder 204 is rotatably sealed and installed inside the sealing end cap 203. A water inlet hole 206 is opened at the other end of the centrifuge cylinder 204. A first guide hood 207 is rotatably sleeved on the centrifuge cylinder 204 around the water inlet hole 206. The inner cavity of the first guide hood 207 is connected to the inside of the centrifuge cylinder 204 through the water inlet hole 206. A water inlet pipe 208 is connected to the first guide hood 207. The top of pipe 208 penetrates the top wall of sewage tank 202 and extends to the outside of sewage tank 202. The first guide hood 207 is fixedly connected to sewage tank 202 through water inlet pipe 208. The end of sewage conveying pipe 004 away from sewage pump 003 is connected to water inlet pipe 208. Sewage generated during the production of recycled kraft paper can be introduced into centrifuge cylinder 204 for filtration along water inlet pipe 208 and first guide hood 207. The filtered sewage falls into sewage tank 202 through filter hole 205, while large particulate impurities are retained in centrifuge cylinder 204. A manifold 209 is installed on the bottom wall of the middle section of sewage tank 202. The bottom end of manifold 209 penetrates support base 201 and extends into sedimentation tank 101 to introduce the pre-filtered sewage into sedimentation tank 101 for secondary treatment.

[0023] like Figures 4-6As shown, a transmission pipe 301 is fixedly connected to one end of the centrifuge cylinder 204 near the first guide shroud 207. The transmission pipe 301 passes through the end side wall of the sewage tank 202 and is rotatably connected to the sewage tank 202, allowing the centrifuge cylinder 204 to rotate inside the sewage tank 202. A motor 302 is fixedly installed on one end of the support base 201 near the transmission pipe 301. An upper pulley 303 and a lower pulley 304 are respectively installed on the end of the transmission pipe 301 outside the sewage tank 202 and the middle section of the output end of the motor 302. The upper pulley 303 and the lower pulley 304 are connected by a belt ring 305. When the motor 302 is started, the centrifuge cylinder 204 fixedly connected to the transmission pipe 301 can be driven to rotate by the motor 302 in conjunction with the belt ring 305, the lower pulley 304 and the upper pulley 303. Under the action of centrifugal force, large particulate impurities retained in the centrifuge cylinder 204 are dehydrated, which facilitates the subsequent treatment of large particulate impurities.

[0024] like Figures 5-7 As shown, a duct 401 is installed inside the centrifuge cylinder 204. The duct 401 is coaxially arranged with the centrifuge cylinder 204, and one end of the duct 401 passes through the sealing end cover 203 and is fixedly connected to the sealing end cover 203. A spiral plate 402 is fixedly connected to the outer surface of the duct 401. A slag discharge pipe 403 is fixedly connected to the sealing end cover 203 below the duct 401. The duct 401 is fixedly connected to the sewage tank 202 through the sealing end cover 203. When the centrifuge cylinder 204 rotates inside the sewage tank 202, the spiral plate 402 installed on the duct 401 rotates relative to the centrifuge cylinder 204. The spiral plate 402 can be used in conjunction with the duct 401 to transport large particulate impurities retained in the centrifuge cylinder 204 towards the slag discharge pipe 403. Finally, the large particulate impurities are discharged from the centrifuge cylinder 204 through the slag discharge pipe 403, which facilitates the collection and treatment of large particulate impurities.

[0025] like Figures 4-6As shown, a sealed gas collecting hood 501 is rotatably fitted onto the output end of the motor 302. The bottom of the gas collecting hood 501 is fixedly connected to the support base 201. A fan blade 502 is fixedly connected to a section of the motor 302 output end located inside the gas collecting hood 501. An air supply pipe 503 is connected to the top of the gas collecting hood 501. The top end of the air supply pipe 503 is rotatably connected to the transmission pipe 301. An exhaust pipe 505 is installed on the end of the air duct 401 near the slag discharge pipe 403. When the motor 302, in conjunction with the belt ring 305, drives the centrifuge cylinder 204 to rotate, it will drive the fan blade 502 to rotate synchronously. During the rotation of the fan blade 502, it can draw external air into the air collection hood 501 and transport the gas to the air duct 401 along the air delivery pipe 503 and the transmission pipe 301. The spiral plate 402 has an exhaust chamber 504 that communicates with the air duct 401. After the flowing air enters the air duct 401, it flows spirally along the exhaust chamber 504 and is finally discharged through the exhaust pipe 505. During the spiral flow of the air, it will hit the inner wall of the spiral plate 402, causing the spiral plate 402 to vibrate. Using this vibration, a small amount of large particles of impurities attached to the spiral plate 402 can be shaken off.

[0026] like Figures 8-10 As shown, a flocculation cylinder 601 is installed inside the sedimentation tank 101. The top of the flocculation cylinder 601 is fixedly connected to the bottom of the manifold 209 through a connecting pipe 602. Wastewater that has undergone preliminary filtration can enter the flocculation cylinder 601 along the connecting pipe 602. A second guide hood 603 is fixedly sleeved around the top of the flocculation cylinder 601. Multiple nozzles 604 connected to the inside of the flocculation cylinder 601 are installed on the second guide hood 603. The multiple nozzles 604 are distributed in a ring at equal intervals. A flocculant addition pipe 605 is connected to one side of the outer wall of the second guide hood 603. The end of the flocculant addition pipe 605 away from the second guide hood 603 passes through the side wall of the sedimentation tank 101 and is fixedly connected to the sedimentation tank 101. Flocculant can be added into the flocculation cylinder 601 by an external flocculant addition device in conjunction with the flocculant addition pipe 605 and the nozzles 604. The flocculant combines with the tiny impurities in the wastewater to form flocs, thereby achieving flocculation of the tiny impurities in the wastewater.

[0027] like Figure 2 and Figure 9As shown, an air stone 606 is fixedly installed on the bottom wall of the inner cavity of the flocculation cylinder 601. An aeration pipe 607 is connected to the air stone 606. The bottom end of the exhaust pipe 505 is fixedly connected to the aeration pipe 607. The air discharged from the air duct 401 can be transported to the air stone 606 through the exhaust pipe 505 along the aeration pipe 607. A large number of bubbles are generated by the air stone 606. The movement and impact of these bubbles cause turbulence in the wastewater containing flocculant in the flocculation cylinder 601, which accelerates the binding efficiency of the flocculant and the tiny impurities in the wastewater. At the same time, it can prevent the problem that the flocs formed by the initial flocculation of tiny impurities and flocculant are easily broken by the impact of the stirring device when the wastewater is stirred by the traditional stirring structure, which is inconvenient for users.

[0028] A spiral-shaped buffer pipe 701 is connected to the bottom of the flocculation cylinder 601. A safety valve is installed at the connection between the buffer pipe 701 and the flocculation cylinder 601. A buffer cover 702 is fitted over the outside of the buffer pipe 701, and the top of the buffer cover 702 is fixedly connected to the outer wall of the buffer pipe 701. When the water level in the flocculation cylinder 601 reaches a set height (i.e., the water pressure at the bottom of the flocculation cylinder 601 reaches a set value), the safety valve opens. At this time, the wastewater in the flocculation cylinder 601 will spiral down through the buffer pipe 701 to the inner wall of the buffer cover 702 and flow downwards along the inner wall of the buffer cover 702. Because an overflow pipe 703 is installed on the side wall of the sedimentation tank 101 between the bottom end of the buffer pipe 701 and the bottom end of the buffer cover 702, the water level in the sedimentation tank 101 is always below the overflow pipe 703. When the flowing sewage falls into the static water body in the sedimentation tank 101, it will quickly calm down due to the buffering and viscous resistance of the static water body in the sedimentation tank 101. This avoids the problem that in traditional stirring methods, after stirring stops, the sewage will still have a long period of fluidity due to inertia, making it difficult for flocs to combine and affecting the flocculation effect of small impurities in the sewage.

[0029] like Figure 1 and Figure 2 As shown, a ladder 801 is vertically installed on the outer wall of the sedimentation tank 101. A protective frame 802 is fixedly connected to the outer side of the top of the ladder 801. A maintenance walkway 803 is provided on the top of the sedimentation tank 101 and is fixedly connected to the protective frame 802, so that users can climb to the top of the sedimentation tank 101 via the ladder 801 to maintain the equipment installed on the top of the sedimentation tank 101.

[0030] like Figure 11As shown, a type of recycled kraft paper comprises, from top to bottom, a surface layer 901, a core layer 902, and a bottom layer 903. The surface layer 901, core layer 902, and bottom layer 903 are integrally formed into a single structure through a wet papermaking process. The pulp of the surface layer 901 consists of 30%–50% wood pulp and 50%–70% domestic waste OCC medium fiber pulp. The pulp of the core layer 902 consists of 40%–50% domestic waste OCC long fiber pulp, 40%–50% domestic waste OCC short fiber pulp, and 10%–20% recycled waste pulp. The pulp of the bottom layer 903 consists of 40%–50% domestic waste OCC long fiber pulp, 40%–50% domestic waste OCC short fiber pulp, and 10%–20% recycled waste pulp. The wood pulp is one or more mixtures of unbleached softwood pulp, unbleached eucalyptus pulp, and roll substitute wood pulp. The weight of the recycled kraft paper is 95–210 g / m².

[0031] It should be noted that, in the use of this type of recycled kraft paper and its production device, firstly, surface layer 901 slurry, core layer 902 slurry and bottom layer slurry 903 slurry are prepared according to the slurry ratio. Then, the prepared slurry is fed into the three-layer composite forming paper machine 001 through a three-layer flow. The three-layer composite forming paper machine 001 precisely controls the jet speed to spray the surface layer 901 slurry, core layer 902 slurry and bottom layer 903 onto the three-layer forming wire to form surface layer 901, core layer 902 and bottom layer 903 respectively. Next, the formed surface layer 901, core layer 902 and bottom layer 903 are precisely composited, and after pressing and dewatering, drying, surface coating and leveling, recycled kraft paper can be obtained. Wastewater generated during the production process and during the pressing process falls into the collection pipe 002 and, under the action of gravity, converges at the end of the collection pipe 002 where the wastewater pump 003 is installed. At this time, the wastewater pump 003 is turned on, and in conjunction with the wastewater conveying pipe 004, the wastewater is introduced into the centrifuge cylinder 204 along the inlet pipe 208 and the first guide shroud 207. The filter holes 205 on the centrifuge cylinder 204 are used to initially filter large particulate impurities in the wastewater. At the same time, the motor 302 is started. The motor 302, in conjunction with the belt ring 305, the lower belt pulley 304 and the upper belt pulley 303, drives the centrifuge cylinder 204, which is fixedly connected to the transmission pipe 301, to rotate. Under the action of centrifugal force, the large particulate impurities retained in the centrifuge cylinder 204 are dehydrated, reducing the weight of the large particulate impurities, which is convenient for subsequent processing of the large particulate impurities. Because a duct 401 is installed inside the centrifuge cylinder 204, one end of which is fixedly connected to the sewage tank 202 via a sealing end cap 203, and a spiral plate 402 is fixedly connected to the outer surface of the duct 401, when the centrifuge cylinder 204 rotates inside the sewage tank 202, the spiral plate 402 installed on the duct 401 rotates relative to the centrifuge cylinder 204. The spiral plate 402, in conjunction with the duct 401, can be used to transport large particulate impurities retained in the centrifuge cylinder 204 toward the slag discharge pipe 403. Finally, the large particulate impurities are discharged from the centrifuge cylinder 204 through the slag discharge pipe 403, which facilitates the discharge and collection of large particulate impurities retained in the centrifuge cylinder 204.

[0032] A fan blade 502 is fixedly connected to the output end of the motor 302. A gas collection hood 501 is sleeved around the fan blade 502. When the motor 302 drives the centrifuge cylinder 204 to rotate in conjunction with the belt ring 305, it will drive the fan blade 502 to rotate synchronously. During the rotation of the fan blade 502, it can draw external air into the gas collection hood 501 and transport the gas along the gas delivery pipe 503 and the transmission pipe 301 to the air duct 401. The spiral plate 402 has an exhaust chamber 504 that communicates with the air duct 401. After the flowing air enters the air duct 401, it flows spirally along the exhaust chamber 504 and is finally discharged through the exhaust pipe 505. During the spiral flow of the air, it will hit the inner wall of the spiral plate 402, causing the spiral plate 402 to vibrate. Using this vibration, a small amount of large particles of impurities attached to the spiral plate 402 can be shaken off, reducing the residue of large particles of impurities in the centrifuge cylinder 204.

[0033] The wastewater, after preliminary filtration through filter holes 205, is introduced into the flocculation cylinder 601 through the manifold 209 and connecting pipe 602. An air stone 606 is installed at the bottom of the flocculation cylinder 601. The bottom end of the exhaust pipe 505 is connected to the inside of the air stone 606 through the aeration pipe 607, which introduces the air discharged from the air duct 401 into the air stone 606. A large number of bubbles are generated by the air stone 606, and the movement and impact of these bubbles cause turbulence in the wastewater containing flocculant in the flocculation cylinder 601. This accelerates the binding efficiency of the flocculant and the tiny impurities in the wastewater. At the same time, it can prevent the problem of the flocs formed by the initial flocculation of tiny impurities and flocculant in the traditional method of stirring the wastewater, which is easily broken by the impact of the stirring device, making it inconvenient for users.

[0034] Wastewater thoroughly mixed with flocculant is discharged through buffer pipe 701. Buffer pipe 701 has a spiral structure, which allows the wastewater mixed with flocculant to slowly fall down along the inner wall of buffer cover 702. When the flowing wastewater falls into the still water in sedimentation tank 101, it will quickly calm down due to the buffering and viscous resistance of the still water in sedimentation tank 101. This avoids the problem that after the stirring stops, the wastewater will still have a long period of fluidity due to inertia, making it difficult for flocs to combine and affecting the flocculation effect of small impurities in the wastewater.

[0035] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A recycled kraft paper production apparatus, comprising a three-layer composite forming paper machine (001), wherein a collection pipe (002) is installed at the bottom of the three-layer composite forming paper machine (001), one end of the collection pipe (002) is connected to a sewage pump (003), the drainage end of the sewage pump (003) is connected to a sewage conveying pipe (004), a sedimentation tank (101) is provided on one side of the three-layer composite forming paper machine (001), a filter structure is installed on the top of the sedimentation tank (101) through a support base (201), and the bottom end of the filter structure is connected to the sedimentation tank (101) through a manifold (209), characterized in that: A drive assembly for driving the filter structure to rotate is installed at one end of the support base (201). A material conveying assembly for discharging filter residue is installed on the filter structure. An air extraction device is connected to one end of the material conveying assembly, and an exhaust pipe (505) is connected to the other end of the material conveying assembly. A flocculation cylinder (601) is installed inside the sedimentation tank (101). The top of the flocculation cylinder (601) is fixedly connected to the bottom end of the manifold (209) through a connecting pipe (602). A flocculant addition assembly is installed around the top of the flocculation cylinder (601). An air stone (606) is fixedly installed on the bottom wall of the inner cavity of the flocculation cylinder (601). An aeration pipe (607) is connected to the air stone (606). The bottom end of the exhaust pipe (505) is fixedly connected to the aeration pipe (607). The bottom end of the flocculation tube (601) is connected to a buffer tube (701) with a spiral structure. A buffer cover (702) is fitted on the outside of the buffer tube (701). The top of the buffer cover (702) is fixedly connected to the outer wall of the buffer tube (701). An overflow pipe (703) is installed on the side wall of the sedimentation tank (101) between the bottom end of the buffer tube (701) and the bottom end of the buffer cover (702).

2. The recycled kraft paper production apparatus according to claim 1, characterized in that: The bottom of the sedimentation tank (101) is funnel-shaped. Support legs (102) are fixedly installed on the bottom side wall of the sedimentation tank (101). A drain pipe (103) is connected to the bottom of the sedimentation tank (101). A valve (104) is installed at the connection between the drain pipe (103) and the sedimentation tank (101). A flow stabilizing ring (105) is fixedly connected to the inner wall of the sedimentation tank (101) above the drain pipe (103).

3. The recycled kraft paper production apparatus according to claim 1, characterized in that: The filtration structure includes a wastewater tank (202) fixedly installed on the top of the support base (201). A sealing end cap (203) is fixedly connected to one end of the wastewater tank (202). A centrifuge cylinder (204) is installed inside the wastewater tank (202). Filter holes (205) are opened on the side wall of the centrifuge cylinder (204). One end of the centrifuge cylinder (204) is rotatably and sealingly installed inside the sealing end cap (203). A water inlet hole (206) is opened at the other end of the centrifuge cylinder (204). A first guide shroud (207) is rotatably mounted on the centrifuge cylinder (204) around the hole (206). An inlet pipe (208) is connected to the first guide shroud (207). The top end of the inlet pipe (208) penetrates the top wall of the sewage tank (202) and is fixedly connected to the sewage tank (202). The end of the sewage conveying pipe (004) away from the sewage pump (003) is connected to the inlet pipe (208). The manifold (209) is installed on the bottom wall of the middle section of the sewage tank (202).

4. The recycled kraft paper production apparatus according to claim 3, characterized in that: The centrifuge tube (204) is fixedly connected to a transmission pipe (301) at the end away from the first guide shroud (207). The transmission pipe (301) passes through the end side wall of the sewage tank (202) and is rotatably connected to the sewage tank (202). The drive assembly includes a motor (302) fixedly connected to the support base (201). An upper pulley (303) and a lower pulley (304) are respectively installed on the end of the transmission pipe (301) located outside the sewage tank (202) and the middle section of the output end of the motor (302). The upper pulley (303) and the lower pulley (304) are connected by a belt ring (305).

5. The recycled kraft paper production apparatus according to claim 4, characterized in that: The material conveying assembly includes an air duct (401) installed inside the centrifuge cylinder (204) and coaxially arranged with the centrifuge cylinder (204). One end of the air duct (401) passes through the sealing end cap (203) and is fixedly connected to the sealing end cap (203). A spiral plate (402) is fixedly connected to the outer surface of the air duct (401). An exhaust chamber (504) communicating with the air duct (401) is opened in the spiral plate (402). A slag discharge pipe (403) is fixedly connected to the sealing end cap (203) below the air duct (401). An exhaust pipe (505) is installed on the end of the air duct (401) near the slag discharge pipe (403).

6. The apparatus for producing recycled kraft paper according to claim 4, characterized in that: The air extraction device includes an air collection hood (501) sleeved on the output end of the motor (302). The bottom of the air collection hood (501) is fixedly connected to the support base (201). A fan blade (502) is fixedly connected to a section of the output end of the motor (302) located inside the air collection hood (501). An air supply pipe (503) is connected to the top of the air collection hood (501). The top end of the air supply pipe (503) is rotatably connected to the transmission pipe (301).

7. The apparatus for producing recycled kraft paper according to claim 1, characterized in that: The flocculant addition assembly includes a second guide shroud (603) fixedly sleeved on the periphery of the top of the flocculation cylinder (601). Multiple nozzles (604) communicating with the inside of the flocculation cylinder (601) are installed on the second guide shroud (603). The multiple nozzles (604) are distributed equidistantly in a ring. A flocculant addition pipe (605) is connected to the outer wall of one side of the second guide shroud (603). The end of the flocculant addition pipe (605) away from the second guide shroud (603) passes through the side wall of the sedimentation tank (101) and is fixedly connected to the sedimentation tank (101).

8. The apparatus for producing recycled kraft paper according to claim 1, characterized in that: A ladder (801) is vertically installed on the outer wall of the sedimentation tank (101), and a protective frame (802) is fixedly connected to the outer side of the top of the ladder (801). A maintenance walkway (803) is fixedly connected to the protective frame (802) on the top of the sedimentation tank (101).

9. A type of recycled kraft paper, characterized in that, From top to bottom, it includes a surface layer (901), a core layer (902), and a bottom layer (903). The surface layer (901), core layer (902), and bottom layer (903) are compositely formed into an integral structure through a wet papermaking process. The pulp of the surface layer (901) consists of 30%–50% wood pulp and 50%–70% domestic waste OCC medium fiber pulp. The pulp of the core layer (902) consists of 40%–50% domestic waste OCC long fiber pulp and 40%… The pulp of the bottom layer (903) consists of 40%–50% domestic waste OCC short fiber pulp, 40%–50% domestic waste OCC short fiber pulp and 10%–20% recycled waste pulp; the wood pulp is one or more of unbleached softwood pulp, unbleached eucalyptus pulp and roll substitute wood pulp; and the weight of the recycled kraft paper is 95–210 g / m².

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