Chemical thermo-mechanical pulp system

Abstract

The invention provides a chemical thermo-mechanical pulp washing system which comprises a drum type vacuum pulp washer, the drum type vacuum pulp washer comprises a machine shell, a rotary drum is arranged in the machine shell, cells are evenly distributed on the rotary drum in the circumferential direction, the adjacent cells are separated through partition plates, corrugated filter plates are arranged in the cells, and filter screens are arranged on the outer sides of the corrugated filter plates. Pulling plates are axially arranged at the positions, corresponding to the partition plates, of the outer side of the filter screen, elastic moving parts in one-to-one correspondence with the pulling plates are arranged at the two ends of the rotary drum, the elastic moving parts move in the radial direction, the ends of the pulling plates are connected with the elastic moving parts, a jacking assembly is arranged on the machine shell on the pulp stripping side of the rotary drum, and the jacking assembly enables the pulling plates to move outwards in the radial direction through the elastic moving parts. According to the drum type vacuum pulp washer, through cooperation of the pulling plate, the elastic moving part and the jacking assembly, the bonding strength between a material layer and the filter screen is reduced, pulp residues on the surface of the filter screen are reduced, and the service life of the filter screen is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of papermaking, in particular to a chemical thermo-mechanical pulp system. BACKGROUND

[0002] The chemical thermo-mechanical pulp system combines chemical pretreatment and mechanical disintegration for pulping, mainly composed of the following parts: wood chip washing, impregnation, high-concentration refining, pre-bleaching washing, bleaching, post-bleaching washing, low-concentration refining, screening and pulp residue regrinding, etc. The washing process needs to use a washing machine, such as a drum vacuum washing machine.

[0003] The drum vacuum washing machine includes a machine shell and a rotating drum, which is divided into a vacuum washing area and a pulp stripping and exhaust area along the circumference. The pulp slurry is filtered and washed in the vacuum washing area to form a material layer on the surface of the rotating drum. The pulp stripping side of the rotating drum is provided with an air scraper to strip the material layer attached to the surface of the rotating drum and crush and transport it through a spiral conveyor. However, the following problems may exist during use: mainly through the air scraper for pulp stripping, the material layer is easily left on the surface of the filter screen, and the filter screen needs to be high-pressure washed subsequently. If there is a lot of residual pulp, the high-pressure washing effect is limited, the filter screen is easily clogged, and the service life is affected.

[0004] In addition, screening and pulp residue regrinding are mainly used to recover useful fibers remaining in the pulp residue. The existing equipment needs to be further improved in terms of pulp residue processing and conveying efficiency. SUMMARY

[0005] The present application provides a chemical thermo-mechanical pulp system. The drum vacuum washing machine reduces the bonding strength between the material layer and the filter screen through the cooperation of the pull plate, the elastic moving part and the jacking assembly, reduces the residual pulp on the surface of the filter screen, and prolongs the service life of the filter screen.

[0006] The technical scheme of the present application is as follows: a chemical thermo-mechanical pulp system includes a drum vacuum washing machine, the drum vacuum washing machine includes a machine shell, a rotating drum is arranged in the machine shell, the rotating drum is uniformly distributed with cells along the circumference, adjacent cells are separated by a partition plate, a corrugated filter plate is arranged in the cell, a filter screen is arranged on the outside of the corrugated filter plate, a pull plate is arranged on the outside of the filter screen corresponding to the position of the partition plate along the axial direction, elastic moving parts corresponding to the pull plates are arranged at both ends of the rotating drum, the elastic moving parts move along the radial direction, the end of the pull plate is connected with the elastic moving part, a jacking assembly is arranged on the machine shell of the pulp stripping side of the rotating drum, and the jacking assembly moves the pull plate radially outward through the elastic moving part.

[0007] Further, the stripping side of the rotary drum is provided with an air doctor, and the lifting assembly is located at the feeding side of the air doctor, the lifting assembly comprises a top block, the side of the top block away from the air doctor is a first inclined surface, and the other side is a vertical surface; the elastic moving part comprises an elastic telescopic rod, and the moving end of the elastic telescopic rod is connected with the pull plate, and the side of the moving end close to the first inclined surface is a second inclined surface; with the rotation of the rotary drum, the moving end moves radially outward along the first inclined surface through the second inclined surface.

[0008] Further, the stripping side of the rotary drum is provided with a conveying groove, the discharging end of the air doctor is located above the conveying groove, the conveying groove is provided with a conveying spiral shaft, the upper end of the conveying groove is provided with a cutting net capable of being lifted elastically, and the end of the conveying spiral shaft is provided with a step pulley, and the lower end of the cutting net is fixed with a fixed block matched with the step pulley.

[0009] Further, the upper side of the cutting net is provided with a spraying pipe, and the spraying pipe is provided with a downward spraying head.

[0010] Further, the wood chip washing and impregnating mechanism, the refining and bleaching mechanism, the pulp washing mechanism, the two-stage refining mechanism, the three-stage refining mechanism and the screening and pulp residue regrinding mechanism are sequentially connected.

[0011] Further, the screening and pulp residue regrinding mechanism comprises a shell, a rotating shaft is arranged in the shell in the axial direction, a grinding roller is fixed on the rotating shaft, feeding spiral blades are arranged on the rotating shaft at the feeding side of the grinding roller, discharging spiral blades are arranged on the rotating shaft at the discharging side, and the pitch of the discharging spiral blades is smaller than that of the feeding spiral blades; the outer side of the grinding roller is provided with a rotating screen cylinder, the rotating directions of the screen cylinder and the grinding roller are opposite or different; the outer wall of the screen cylinder is provided with spiral conveying blades, and spiral conveying grooves are arranged on the grinding roller, and the conveying directions of the spiral conveying grooves and the spiral conveying blades are opposite.

[0012] Further, one end of the shell is provided with a feeding port, the feeding port is communicated with the inner side of the screen cylinder, the other end of the shell is provided with a coarse pulp outlet, the coarse pulp outlet is communicated with the inner side of the screen cylinder, and the lower side of the shell close to the one end of the feeding port is provided with a fine pulp outlet.

[0013] The drum-type vacuum pulp washer has the following beneficial effects: The drum-type vacuum pulp washer has the following beneficial effects:

[0014] The drum type vacuum pulp washing machine of the present application cuts the peeled material layer through a cutting net first, then further crushes and conveys through a conveying spiral shaft, and at the same time, sprays diluent liquid through a spray pipe to flush the cutting net, so as to preliminarily stir and dilute the pulp while conveying the pulp, thereby shortening the subsequent pulp dilution process.

[0015] The screening and pulp residue regrinding mechanism of the present application cooperates the rotating grinding roller and the rotating screen cylinder, regrinds while screening along with the conveying of the pulp, and improves the screening and regrinding efficiency; is arranged obliquely relative to the shell, discharges the fine pulp by self weight, and conveys the fine pulp through the spiral conveying blade, which is beneficial to improve the discharge rate of the fine pulp. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0017] Figure 1 is a structural schematic view of the present application; Figure 2 is a structural schematic view of the drum type vacuum pulp washing machine of embodiment 1; Figure 3 is a structural schematic view of the drum type vacuum pulp washing machine of embodiment 1; Figure 1 is a partial enlarged view of B in the drum type vacuum pulp washing machine of embodiment 1; Figure 4 is a structural schematic view of the elastic telescopic rod; Figure 5 is a structural schematic view of the top block; Figure 6 is a structural schematic view of the drum type vacuum pulp washing machine of embodiment 2; Figure 7 is a structural schematic view of the drum type vacuum pulp washing machine of embodiment 2; Figure 6 is a partial enlarged view of B in the drum type vacuum pulp washing machine of embodiment 2; Figure 8 is a structural schematic view of the screening and pulp residue regrinding mechanism.

[0018] Wood chip washing and impregnation mechanism 1, pulping and bleaching mechanism 2, pulp washing mechanism 3, two-stage pulping mechanism 4, three-stage pulping mechanism 5, screening and pulp residue re-grinding mechanism 6, machine casing 8, drum 9, air scraper 10, compartment 11, partition 12, corrugated filter plate 13, filter screen 14, pull plate 16, elastic telescopic rod 17, top block 18, conveying trough 19, conveying screw shaft 20, guide rod 21, cutting screen 22, support spring 24, reducing wheel 25, fixing block 26, spray pipe 27, outer casing 28, first drive motor 29, rotating shaft 30, grinding roller 31, feed screw blade 32, discharge screw blade 33, screen cylinder 34, transmission gear ring 35, second drive motor 36, screw conveyor blade 37, screw conveyor trough 38, feed inlet 39, coarse pulp outlet 40, fine pulp outlet 41. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1 like Figure 1 As shown, a chemithermomechanical pulping system includes a wood chip washing and impregnation unit 1, a pulping and bleaching unit 2, a pulp washing unit 3, a second-stage pulping unit 4, a third-stage pulping unit 5, and a screening and pulp residue regrinding unit 6 connected in sequence. The wood chip washing and impregnation unit 1, the pulping and bleaching unit 2, the second-stage pulping unit 4, and the third-stage pulping unit 5 are all existing equipment.

[0021] like Figures 2-5 As shown, the washing mechanism 3 includes a drum vacuum washer, which includes a housing 8 and a rotating drum 9 inside the housing 8. The rotating drum 9 is driven to rotate by a motor and is divided into a vacuum washing zone and a stripping and exhaust zone. An air scraper 10 is fixed inside the housing 8 on the stripping side of the rotating drum 9.

[0022] The drum 9 has circumferentially distributed chambers 11, which are separated by partitions 12. Corrugated filter plates 13 are fixed inside the chambers 11. Filter screens 14 are wrapped around the outside of the corrugated filter plates 13. A pull plate 16 is placed axially on the outside of the filter screen 14 at the position corresponding to the partition 12. Both ends of the drum 9 are provided with elastic moving parts that correspond one-to-one with the pull plates 16. The elastic moving parts include elastic telescopic rods 17. The moving end of the elastic telescopic rod 17 moves radially and is connected to the pull plate 16. The other end is fixedly connected to the end of the drum 9.

[0023] A lifting assembly is provided on the casing 8 on the pulp-stripping side of the drum 9. The lifting assembly causes the pull plate 16 to move radially outward. The lifting assembly is located on the feeding side of the air scraper 10. The lifting assembly includes a top block 18. The side of the top block 18 away from the air scraper 10 is a first inclined surface, and the other side is a vertical surface. The moving end of the elastic telescopic rod 17 is a second inclined surface on the side close to the first inclined surface. As the drum 9 rotates, the second inclined surface moves radially outward along the first inclined surface, and the moving end drives the pull plate 16 to move radially outward.

[0024] The material layer attached to the drum 9 is moved to the stripping side. The lifting component drives the pull plate 16 to move radially outward through the elastic moving part. During the radial outward movement of the pull plate 16, the material layer and the filter screen 14 will be initially separated, reducing the bonding strength between the two. Because the moving distance is small, the material layer will not break. Because the bonding strength between the two is reduced, it is easier for the air scraper 10 to strip the slurry.

[0025] Example 2 This embodiment is basically the same as Embodiment 1, except that, as Figure 6 and 7 As shown, a conveying trough 19 is also fixed inside the casing 8 on the pulping side of the rotary drum 9. The discharge end of the air scraper 10 is located above the conveying trough 19. A motor-driven conveying spiral shaft 20 is installed inside the conveying trough 19. A guide rod 21 is fixed to the upper edge of the conveying trough 19. A cutting mesh 22 is installed at the upper end of the conveying trough 19. The cutting mesh 22 slides vertically along the guide rod 21. A support spring 24 is fitted on the guide rod 21 below the cutting mesh 22.

[0026] Both ends of the conveying screw shaft 20 are fixed with reducing wheels 25, and the lower end of the cutting mesh 22 is fixed with a fixing block 26 that cooperates with the reducing wheels 25. The reducing wheels 25 rotate synchronously with the conveying screw shaft 20. The material layer on the drum 9 enters the upper side of the cutting mesh 22 through the stripping scraper, and then the cutting mesh 22 cuts and falls into the conveying trough 19. It is then further conveyed and crushed by the conveying screw shaft 20. As the conveying screw shaft 20 rotates, when the longer end of the reducing wheel 25 rotates to the fixing block 26, it pushes the fixing block 26 and the cutting mesh 22 upward. This end moves away from the fixing block 26. Due to self-repositioning, the fixing block 26 and the cutting mesh 22 intermittently vibrate the cutting mesh 22, which facilitates the smooth discharge of the material layer on the cutting mesh 22.

[0027] A spray pipe 27 is fixed above the cutting mesh 22, and a downward-facing spray head is fixed on the spray pipe 27. Diluent is sprayed onto the cutting mesh 22 through the spray pipe 27 and the spray head, which washes the cutting mesh 22 and at the same time the diluent falls into the conveying tank 19. The conveying spiral shaft 20 can simultaneously stir and dilute the slurry while conveying it.

[0028] Example 3 This embodiment is basically the same as Embodiment 1 or 2, except that, as shown in Figure 8 The slurry residue regrinding mechanism 6 comprises a shell 28, a rotating shaft 30 driven by a first driving motor 29 is arranged axially in the shell 28. A grinding roller 31 is fixed on the rotating shaft 30, a feeding screw blade 32 is fixed on the rotating shaft 30 at the feeding side of the grinding roller 31, and a discharging screw blade 33 is fixed on the rotating shaft 30 at the discharging side of the grinding roller 31, the pitch of the discharging screw blade 33 is smaller than that of the feeding screw blade 32. The feeding screw blade 32 is used for feeding and conveying the slurry, the discharging screw blade 33 is used for conveying and discharging the thick pulp, the pitch of the discharging screw blade 33 is small, which slows down the conveying of the material and prolongs the regrinding time of the slurry in the grinding roller 31 and the screen cylinder 34.

[0029] A rotating screen cylinder 34 is arranged outside the grinding roller 31, one end of the screen cylinder 34 rotates through the shell 28 and is fixed with a transmission gear ring 35, the transmission gear ring 35 is engaged with a driving gear, the driving gear is connected with a second driving motor 36, the other end of the screen cylinder 34 rotates through the shell 1 at the same side. The second driving motor 36 drives the screen cylinder 34 to rotate through the driving gear and the transmission gear ring 35. The screen cylinder 34 rotates in the opposite direction or at a differential speed with the grinding roller 31, so as to facilitate the regrinding of the slurry residue between the grinding roller 31 and the screen.

[0030] The outer wall of the screen cylinder 34 is fixed with a spiral conveying blade 37, and a spiral conveying groove 38 is arranged on the grinding roller 31, the conveying directions of the spiral conveying groove 38 and the spiral conveying blade 37 are opposite. One end of the shell 28 is fixed with a feeding port 39, the feeding port 39 is communicated with the inner side of the screen cylinder 34, the other end of the shell 28 is fixed with a thick pulp outlet 40, the thick pulp outlet 40 is communicated with the inner side of the screen cylinder 34; the lower side of the shell 28 is fixed with a fine pulp outlet 41 near the one end of the feeding port 39. The spiral conveying blade 37 drives the fine pulp to move towards the fine pulp outlet 41 and is discharged through the fine pulp outlet 41.

[0031] The slurry enters the screen cylinder 34 through the feeding port 39, the feeding screw blade 32 drives the slurry to feed and convey, the fine pulp in the slurry penetrates into the shell 28 through the screen cylinder 34, and the remaining slurry residue enters between the grinding roller 31 and the screen cylinder 34 for regrinding, the spiral conveying groove 38 is used for conveying the slurry residue, the fine pulp formed after regrinding penetrates into the shell 28 through the screen cylinder 34, and the final remaining thick residue is conveyed through the discharging screw blade 33 and discharged through the thick pulp outlet 40; the fine pulp entering the shell 28 is discharged through the fine pulp outlet 41 by the spiral conveying blade 37 with the rotation of the screen cylinder 34.

[0032] The above only describes the preferred embodiments of the present application and is not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A chemithermomechanical pulping system, comprising a drum vacuum washer, the drum vacuum washer including a casing, a rotating drum disposed within the casing, and compartments evenly distributed circumferentially along the upper edge of the rotating drum, adjacent compartments being separated by partitions, corrugated filter plates disposed within the compartments, and filter screens disposed on the outer side of the corrugated filter plates, characterized in that: A pull plate is axially arranged on the outer side of the filter screen at the position corresponding to the partition plate. Both ends of the drum are provided with elastic moving parts that correspond one-to-one with the pull plate. The elastic moving parts move radially. The end of the pull plate is connected to the elastic moving part. A lifting assembly is provided on the casing on the pulping side of the drum. The lifting assembly moves the pull plate radially outward through the elastic moving part.

2. The chemithermomechanical pulping system according to claim 1, characterized in that: An air scraper is provided on the stripping side of the drum. The lifting assembly is located on the feeding side of the air scraper. The lifting assembly includes a top block, and the side of the top block away from the air scraper is a first inclined surface. The elastic moving part includes an elastic telescopic rod. The moving end of the elastic telescopic rod is connected to the pull plate. The side of the moving end near the first inclined surface is a second inclined surface. As the drum rotates, the moving end moves radially outward along the first inclined surface through the second inclined surface.

3. The chemithermomechanical pulping system according to claim 2, characterized in that: The drum is also equipped with a conveying trough on the stripping side. The discharge end of the air scraper is located above the conveying trough. A conveying screw shaft is installed inside the conveying trough. A flexible lifting cutting screen is installed at the upper end of the conveying trough. A different diameter wheel is installed at the end of the conveying screw shaft. A fixing block that cooperates with the different diameter wheel is fixed at the lower end of the cutting screen.

4. The chemithermomechanical pulping system according to claim 3, characterized in that: A spray pipe is installed above the cutting mesh, and a downward-facing spray head is installed on the spray pipe.

5. A chemithermomechanical pulping system according to any one of claims 1-4, characterized in that: It also includes a wood chip washing and impregnation mechanism, a pulping and bleaching mechanism, a pulp washing mechanism, a two-stage pulping mechanism, a three-stage pulping mechanism, and a screening and pulp residue re-grinding mechanism connected in sequence. The pulp washing mechanism includes the aforementioned drum vacuum pulp washing machine.

6. The chemithermomechanical pulping system according to claim 5, characterized in that: The screening and slurry regrinding mechanism includes an outer shell, inside which a rotating shaft is arranged axially. A grinding roller is fixed on the rotating shaft. A feeding spiral blade is arranged on the rotating shaft on the feed side of the grinding roller, and a discharge spiral blade is arranged on the rotating shaft on the discharge side. The pitch of the discharge spiral blade is smaller than that of the feeding spiral blade. A rotating screen cylinder is arranged on the outside of the grinding roller. The screen cylinder rotates in the opposite direction or at a differential speed to the grinding roller. A spiral conveying blade is arranged on the outer wall of the screen cylinder. A spiral conveying groove is arranged on the grinding roller. The conveying directions of the spiral conveying groove and the spiral conveying blade are opposite.

7. The chemithermomechanical pulping system according to claim 6, characterized in that: One end of the outer shell is provided with a feed inlet, which is connected to the inside of the screen cylinder. The other end of the outer shell is provided with a coarse pulp outlet, which is connected to the inside of the screen cylinder. The lower side of the outer shell, near the feed inlet, is provided with a fine pulp outlet.

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