Paper pulp mechanical supercharging preparation system and preparation method thereof

Abstract

The invention discloses a paper pulp mechanical supercharging preparation system and a preparation method thereof.The system comprises a pulper, a cooking device, a washing device, a screening device, a bleaching device and a concentration device, the pulper, the cooking device, a pulp filter press, the washing device, the screening device, the bleaching device and the concentration device are sequentially connected and installed, and the washing device is composed of three-stage to five-stage washing machines; the system further comprises a slurry filter press; and the slurry filter press is connected and mounted at the rear end of the cooking device or the front end of any stage of washing machine in the first three stages of washing devices. According to the system and the preparation method thereof, the pulp yield of paper pulp pulping, the wood raw material conversion rate, the environmental protection property and the quality and value of the paper pulp are improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of pulp preparation and production, in particular to a pulp mechanical pressurization preparation system and a preparation method. BACKGROUND

[0002] In general, industrial preparation of pulp using wood chips as raw material by chemical pulp process needs to go through main processes such as crushing, liquor cooking, washing, screening, bleaching, and concentration. If a chemi-mechanical pulp process is used, there is an additional refining process after the liquor cooking process and before the washing process.

[0003] The above two pulp preparation processes each have advantages and disadvantages. The advantage of the chemical pulp process is that the pulp fiber length is long, the paper strength is high, and it is suitable for processing high-grade paper products. The disadvantage is that the pulp yield is only 40% to 50% because it relies entirely on liquor soaking to decompose and dissolve lignin to separate fibers, and the liquor consumption is large, the recovery is difficult, and the environmental protection is a big problem. The advantage of the chemi-mechanical pulp process is that the pulp yield can reach 80% to 90%, the liquor consumption is relatively small, the recovery is relatively easy, and the environmental protection is relatively better. The disadvantage is that the energy consumption is high because of the mechanical refining process, the fiber is severely damaged, the fiber length is short, the paper strength is low, and it is suitable for processing low-grade paper products.

[0004] If the pulp material after cooking in the chemical pulp process can be added with a certain process before washing, most of the liquor in the pulp material can be separated out to improve the liquor recovery efficiency, reduce the washing water consumption, and improve the washing efficiency, thereby improving the environmental protection of the process, and at the same time, the lignin structure between the fibers is damaged as much as possible without shearing the fibers, the fibers are more easily and more purely separated out through washing and screening, and the pulp yield of the process is improved. If the pulp material after cooking in the chemi-mechanical pulp process is also added with such a process before refining, most of the liquor in the pulp material can be separated out, and the hardness of the pulp material can be reduced, thereby reducing the difficulty and time of refining, reducing the energy consumption of the process, reducing the damage to the fiber length, improving the quality of the produced pulp, reducing the washing water consumption, and improving the washing efficiency, thereby further improving the environmental protection of the process.

[0005] According to statistics and public data, China's annual pulp production is close to 90 million tons. Therefore, by combining the existing chemical pulp and chemi-mechanical pulp processes and adding a certain process to achieve the above process efficiency, a huge cost reduction and quality improvement space can be created for the pulp and paper industry, and a great contribution can be made to the energy saving and carbon reduction of the social economy, the green and low-carbon transformation, and the better realization of the "double carbon" goal. SUMMARY

[0006] The paper pulp mechanical pressurization preparation system and the preparation method can improve the pulp yield, wood raw material conversion rate, environmental protection, and the quality and value of the paper pulp.

[0007] The paper pulp mechanical pressurization preparation system comprises a pulper, a cooking device, a washing device, a screening device, a bleaching device, and a concentration device.

[0008] As an optional embodiment of the paper pulp mechanical pressurization preparation system, the paper pulp mechanical pressurization preparation system further comprises a blow tank, and the pulp press filter is connected and installed at the rear end of the cooking device or the blow tank and the front end of the first three washing devices of the washing device.

[0009] As an optional embodiment of the paper pulp mechanical pressurization preparation system, the paper pulp mechanical pressurization preparation system further comprises a pulper, and the pulp press filter is connected and installed at the rear end of the cooking device or the blow tank and the front end of the first three washing devices of the washing device.

[0010] As an optional embodiment of the paper pulp mechanical pressurization preparation system, the paper pulp mechanical pressurization preparation system further comprises a pulper, and the pulp press filter is connected and installed at the rear end of the cooking device or the blow tank and the front end of the first three washing devices of the washing device.

[0011] As an optional embodiment of the paper pulp mechanical pressurization preparation system, the pulp press filter comprises a filter frame, a pulp distribution device, filter cloth, a filter cloth traction device, a pulp press filter plate, and a pulp hydraulic device.

[0012] As an optional embodiment of the paper pulp mechanical pressurization preparation system, the paper pulp mechanical pressurization preparation system further comprises a pulp sheet breaking device, which is connected and installed at the rear end of the pulp press filter and the front end of the washing device.

[0013] As an optional embodiment of the present invention, the aforementioned mechanical pressurized pulp preparation system further includes a pulp sheet crushing device; the pulp sheet crushing device is connected and installed at the rear end of the pulp filter press, the washing device or the front end of the refiner.

[0014] As an optional embodiment of the present invention, the aforementioned mechanical pressurized pulp preparation system further includes a solid-liquid pre-separation device; the solid-liquid pre-separation device is connected and installed at the rear end of the cooking device and the front end of the slurry filter press.

[0015] As an optional embodiment of the present invention, the aforementioned pulp mechanical pressurization preparation system also includes a solid-liquid pre-separation device; the solid-liquid pre-separation device is connected and installed at the rear end of the cooking device or the spraying bin and the front end of the slurry filter press.

[0016] As an optional embodiment of the present invention, the pulp sheet crushing device in the aforementioned pulp mechanical pressurization preparation system includes a double-roller shredder and / or a double-screw conveyor, a chain crusher or a blade / hammer crusher, and a paddle mixer.

[0017] As an optional embodiment of the present invention, the solid-liquid pre-separation device in the aforementioned mechanical pressurized pulp preparation system is a belt separator or a spiral screen separator.

[0018] The present invention discloses a method for preparing a pulp mechanical supercharging preparation system, which comprises the following steps:

[0019] S1 Preparation: Prepare wood chips that have been free of debris, mud, and other impurities or have completed storage, fermentation, and balanced moisture.

[0020] S2 starts the system: respectively starts the pulper, the cooking device, and / or the spray bin, the pulp filter press, and / or the refiner, the washing device, the screening device, the bleaching device, and the concentrating device, and puts the system into a startup standby state.

[0021] S3 Wood chip crushing: The wood chips prepared in S1 are put into the pulper to be crushed into a particle size of 5 to 20 mm.

[0022] S4 Cooking: The wood chips crushed by the pulper in S3 are put into the cooking device and mixed with chemical liquid to react at a preset temperature and pressure.

[0023] S5 pulp filter pressing and black liquor recovery: the pulp after the cooking reaction in S4 is delivered into the pulp filter press to run filter pressing, the pulp filter press uniformly lays, clamps and directly draws the pulp to the filter pressing area to conduct filter pressing at a pressure of 1-15 MPa, part of the black liquor is discharged from the pulp filter press under pressure and flows into the black liquor recovery tank through the pipeline, and the pulp is filtered into pulp pieces with a dryness of 30%-70%.

[0024] S6 washing and black liquor recovery: the pulp pieces with a dryness of 30%-70% after the filter pressing of the pulp in S5 are delivered into the washing device to conduct three to five stage washing to improve the purity of the pulp and further recover the black liquor in the pulp.

[0025] S7 screening and purification: the pulp after the washing in S6 is delivered into the screening device to remove the uncooked fiber bundles and impurities and improve the cleanliness of the pulp.

[0026] S8 bleaching: the pulp after the screening and purification in S7 is delivered into the bleaching device to conduct bleaching treatment by using chemicals to improve the whiteness.

[0027] S9 concentration: the pulp after the bleaching in S8 is delivered into the concentration device to be concentrated to a dryness of about 3% to form wet pulp suitable for pipeline transportation.

[0028] As an optional embodiment of the present application, in the aforementioned pulp mechanical supercharging preparation method, in S5, the pulp filter pressing and chemical liquor recovery: the pulp after the cooking reaction in S4 is delivered into the pulp laying device of the pulp filter press, the pulp laying device and the filter cloth drawing device are started to run, the pulp laying device uniformly lays and clamps the pulp on the filter cloth and directly draws the pulp to the pulp hydraulic device below and between the pulp filter plates to conduct filter pressing at a pressure of 1-15 MPa, part of the black liquor is discharged from both sides of the pulp filter plate through the filter cloth under the pressure of the pulp hydraulic device and flows into the black liquor recovery tank through the pipeline, and the pulp is filtered into pulp pieces with a dryness of 30%-70%.

[0029] As an optional embodiment of the present application, in the aforementioned pulp mechanical supercharging preparation method, in S5, the pulp is first sprayed into the spraying bin from the cooking device and then delivered into the pulp filter press for filter pressing;

[0030] In S5, the net length of time for the filter pressing of the pulp between the pulp filter plates at a pressure of 1-15 MPa is 10-300 seconds;

[0031] In S6, the pulp pieces with a dryness of 30%-70% are broken and scattered by the pulp piece breaking device before being delivered into the washing device for washing;

[0032] The pulp pieces with a dryness of 30% to 70% in S6 are conveyed into the washing device for washing, and then are conveyed into the refiner for refining after being broken and scattered by the pulp piece breaking device;

[0033] S5 and S6 are exchanged in sequence, and the pulp after cooking is washed by the first, second or third washing machine of the washing device before being subjected to pressure filtration;

[0034] S5 and S6 are exchanged in sequence, and the pulp after cooking is washed by the first, second or third washing machine of the washing device before being subjected to pressure filtration;

[0035] The pulp pieces with a dryness of 30% to 70% in S6 are conveyed into the washing device for washing, and then are conveyed into the refiner for refining after being broken and scattered by the pulp piece breaking device.

[0036] Compared with the prior art, the paper pulp mechanical pressurization preparation system and the preparation method have obvious advantages and beneficial effects. Through the above technical scheme, the paper pulp mechanical pressurization preparation system and the preparation method have at least one of the following advantages and beneficial effects:

[0037] Firstly, the wood pulp yield of the chemical pulp process can be improved;

[0038] Secondly, the pulp refining difficulty, refining time and energy consumption of the chemical mechanical pulp process can be effectively reduced;

[0039] Thirdly, one to two stages of washing can be reduced, the recovery efficiency of black liquor can be greatly improved, the pulp washing water and washing time can be reduced, and the environmental protection of the pulp and paper industry can be improved;

[0040] Fourthly, the separation of fibers and lignin and other impurities is more beneficial, the fiber splitting rate is higher, the fiber bundle is greatly reduced, and the fiber quality is improved, which is beneficial to improve the folding endurance and strength of the paper;

[0041] Fifthly, the conversion rate of papermaking raw materials such as wood is greatly improved, the consumption of resources such as trees is reduced, the comprehensive production cost is greatly reduced, the energy saving and carbon reduction, cost reduction, quality improvement and efficiency improvement of the pulp and paper industry can be effectively promoted, and the production green transformation and upgrading are better to help the realization of the social "double carbon" goal.

[0042] The above description is only a summary of the technical scheme of the present application, in order to more clearly understand the technical means of the present application, and can be implemented according to the content of the specification, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the following preferred embodiments are described in detail, and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 is a schematic view of the structure of embodiment one of the present application.

[0044] Figure 2is the main view schematic diagram of the structure of embodiment two of the present application.

[0045] Figure 3 is the main view schematic diagram of the structure of embodiment three of the present application.

[0046] Figure 4 is the main view schematic diagram of the structure of embodiment four of the present application.

[0047] Figure 5 is the main view schematic diagram of the structure of embodiment five of the present application.

[0048] Figure 6 is the main view schematic diagram of the structure of embodiment six of the present application.

[0049] BRIEF DESCRIPTION OF DRAWINGS

[0050] 1: Pulper 2: Digester

[0051] 3: Blow tank 4: Solid-liquid pre-separation device

[0052] 41: Belt separator 42: Spiral screen separator

[0053] 5: Pulp press 51: Press frame

[0054] 52: Pulp distribution device 53: Filter cloth

[0055] 54: Filter cloth traction device 55: Pulp press plate

[0056] 56: Pulp hydraulic device 6: Pulp sheet breaking device

[0057] 61: Double pair-roller shredder 62: Double screw conveyor

[0058] 63: Chain crusher 64: Blade / hammer crusher

[0059] 65: Paddle mixer 7: Refiner

[0060] 8: Washing device 81: First-stage washing machine

[0061] 82: Second-stage washing machine 83: Third-stage washing machine

[0062] 84: Fourth-stage washing machine 85: Fifth-stage washing machine

[0063] 9: Screening device 10: Bleaching device

[0064] 11: Concentration device DETAILED DESCRIPTION

[0065] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following, in combination with the accompanying drawings and preferred embodiments, describes in detail the specific implementation method, structure, characteristics and effects of the pulp mechanical boosting preparation system and preparation method proposed in the present invention.

[0066] Example 1:

[0067] See also Figure 1 As shown, the mechanical pressurized pulp preparation system of the first embodiment of the present invention is mainly composed of a pulper 1, a cooking device 2, a pulp filter press 5, a washing device 8, a screening device 9, a bleaching device 10 and a concentrating device 11, wherein the pulper 1, the cooking device 2, the pulp filter press 5, the washing device 8, the screening device 9, the bleaching device 10 and the concentrating device 11 are connected and installed in sequence; the washing device 8 consists of three-stage washing machines; the pulp filter press 5 is connected and installed at the rear end of the cooking device 2 and the front end of the first-stage washing machine 81 of the washing device 8.

[0068] The slurry filter press 5 primarily consists of a filter press frame 51, a slurry distribution device 52, a filter cloth 53, a filter cloth traction device 54, slurry filter press plates 55, and a slurry hydraulic device 56. The slurry distribution device 52, the filter cloth traction device 54, and the slurry hydraulic device 56 are connected and mounted on the filter press frame 51. The slurry filter press plates 55 are mounted on the slurry hydraulic device 56. The filter cloth is wrapped around and movably connected to the filter cloth traction device 54, passing between the slurry filter press plates 55. There are ten slurry filter press plates 55, with the upper and lower plates vertically connected and mounted between the lower base and the slider of the slurry hydraulic device 56. In actual application, the number of slurry filter press plates 55 can be increased or decreased according to the required filtration efficiency.

[0069] Example 2:

[0070] See also Figure 2 As shown, the mechanical pressurized pulp preparation system of the second embodiment of the present invention is similar to that of the first embodiment, with the only difference being:

[0071] In order to further improve the production buffering capacity and continuity of the system, the spraying bin 3 is additionally installed at the rear end of the cooking device 2. After the slurry is cooked in the cooking device 2, it is quickly sprayed into the spraying bin 3, and then evenly transported from the spraying bin 3 to the slurry filter press 5 at the rear end for filtration.

[0072] If the pulp discharged from the cooking device 2 has a low solid content, in order to further improve the processing capacity of the mechanical pressure preparation system of the pulp, a solid-liquid pre-separation device 4 is added; the solid-liquid pre-separation device 4 is a belt separator 41 or a spiral screen separator 42, which is connected and installed at the rear end of the blow tank 3 and the front end of the pulp filter 5; the pulp with a low solid content is discharged into the pulp filter 5 after being pre-separated by the belt separator 41 or the spiral screen separator 42 to improve the solid content and then filtered to further separate the black liquor in the pulp and simultaneously crush the lignin structure between fibers.

[0073] The pulp filter 5 is connected and installed between the second-stage washing machine 82 and the third-stage washing machine 83 of the washing device 8.

[0074] In order to further facilitate the increase of the contact area of the pulp and the washing water and improve the washing efficiency, a pulp piece crushing device 6 is added; the pulp piece crushing device 6 is connected and installed at the rear end of the pulp filter 5 and the front end of the washing device 8. The pulp piece crushing device 6 is composed of a double-pair roller shredder 61, or / and a double-spiral conveyor 62, and a chain crusher 63, which are connected and installed in sequence; the pulp piece filtered by the pulp filter 5 is conveyed into the double-pair roller shredder 61 to be shredded into small pieces, and then conveyed into the chain crusher 63 through the double-spiral conveyor 62 to be crushed and scattered, and then conveyed into the washing device 8 at the rear end for washing.

[0075] Example Three

[0076] Please refer to Figure 3 The pulp mechanical pressure preparation system of the third embodiment of the present application is similar to that of the first embodiment, and the difference is only that:

[0077] In the chemical pulp process, the pulp needs to be ground, and a grinding machine 7 is added; the grinding machine 7 is connected and installed at the rear end of the pulp filter 5 and the front end of the washing device 8. In the production of pulp, after the pulp completes the chemical liquid cooking reaction in the cooking device 2 and the solid-liquid separation by the pulp filter 5, the pulp is ground and refined by the grinding machine 7 and then conveyed into the washing device 8 for washing.

[0078] The pulp piece crushing device 6 is composed of the double-spiral conveyor 62 and the blade / hammer crusher 64.

[0079] Example Four

[0080] Please refer to Figure 4 The pulp mechanical pressure preparation system of the fourth embodiment of the present application is similar to that of the second embodiment, and the difference is only that:

[0081] The slurry sheet breaking device 6 is composed of the double screw conveyor 62 and the paddle mixer 65.

[0082] Embodiment five:

[0083] Referring to Figure 5 The pulp mechanical supercharging preparation system of embodiment five of the present application is similar to that of embodiment one, with the only difference being that:

[0084] In order to further improve the slurry solid-liquid separation processing capacity, the slurry hydraulic device 56 of the slurry filter press 5 is installed in series through two sets of filter cloth 53.

[0085] Embodiment six:

[0086] Referring to Figure 6 The pulp mechanical supercharging preparation system of embodiment six of the present application is similar to that of embodiment one, with the only difference being that:

[0087] In order to further improve the slurry solid-liquid separation processing capacity and avoid the loss of pulp fiber length due to the bending of the slurry plate during the solid-liquid separation process, the slurry hydraulic device 56 of the slurry filter press 5 is installed in series through three sets of filter cloth 53, and the slurry filter plate 55 in the three sets of slurry hydraulic device 56 is installed in two blocks, respectively, and the slurry distribution device 52 and the filter cloth traction device 54 are correspondingly installed in two sets of upper and lower parallel connection.

[0088] The preparation method of the pulp mechanical supercharging preparation system of the present application comprises the following steps:

[0089] S1: Prepare wood chips for removing impurities such as debris, sand, etc., or for storing and fermenting, and balancing moisture.

[0090] S2: Start the system: start the pulper 1, the cooking device 2, or / and the spray bin 3, the slurry filter press 5, or / and the grinding machine 7, the washing device 8, the screening device 9, the bleaching device 10, and the concentration device 11, respectively, so that the system is in a standby state.

[0091] S3: Wood chip breaking: put the wood chips prepared in S1 into the pulper 1 to break and refine to a particle size of 5-20mm.

[0092] S4: Cooking: put the broken wood chips after the pulper 1 in S3 into the cooking device 2 to mix with chemical liquid, and react under pre-set high temperature and high pressure.

[0093] S5 slurry filter pressing and black liquor recovery: the slurry after the cooking reaction in S4 is delivered to the slurry distributing device 52 of the slurry filter press 5, the slurry distributing device 52 and the filter cloth traction device 54 are started to operate, the slurry distributing device 52 uniformly lays the slurry on the filter cloth 53 and directly delivers the slurry to the slurry hydraulic device 56 and between the slurry filter plates 55 under the action of 1-15 MPa superhigh pressure for filter pressing, part of the black liquor is discharged from both sides of the slurry filter plates 55 under the action of the pressure of the slurry hydraulic device 56 and flows into the black liquor recovery tank through the pipeline, and the slurry is filter pressed into slurry pieces with a dryness of 30%-70%.

[0094] S6 washing and black liquor recovery: the slurry pieces with a dryness of 30%-70% after the filter pressing of the slurry filter press 5 in S5 are delivered to the washing device 8 for three to five stage washing to improve the purity of the slurry and further recover the black liquor in the slurry.

[0095] S7 screening and purification: the slurry after the washing in S6 is delivered to the screening device 9 to remove the unsteamed fiber bundles and impurities and improve the cleanliness of the slurry.

[0096] S8 bleaching: the slurry after the screening and purification in S7 is delivered to the bleaching device 10 for bleaching treatment by using reagents to improve the whiteness.

[0097] S9 concentration: the slurry after the bleaching in S8 is delivered to the concentration device 11 for concentration to a dryness of about 3% to form wet pulp suitable for pipeline delivery.

[0098] In one specific embodiment of the preparation method of the pulp mechanical supercharging preparation system of the application, wood chips are used as the pulp preparation raw material and a chemical pulp preparation process is adopted, and the specific steps of the preparation method are as follows:

[0099] S1 material preparation: wood chips after the removal of impurities such as debris and sand or after the completion of storage fermentation and moisture balance are prepared for use.

[0100] S2 system start: the pulper 1, the cooking device 2, the slurry filter press 5, the washing device 8, the screening device 9, the bleaching device 10 and the concentration device 11 are started respectively, so that the system is in a start standby state.

[0101] S3 wood chip crushing: the wood chips prepared in S1 are put into the pulper 1 for crushing and refining to a particle size of 10 mm.

[0102] S4 cooking: the crushed wood chips after the pulping of the pulper 1 in S3 are put into the cooking device 2 to mix with NaOH and Na2S liquor, and are cooked at a high temperature of 160-170 ℃ and a high pressure of 8 bar for 2 hours.

[0103] S5 pulp pressure filtration and black liquor recovery: the pulp in S4 after the completion of the cooking reaction is delivered to the pulp distribution device 52 of the pulp pressure filter 5, the pulp distribution device 52 and the filter cloth traction device 54 are started, the pulp distribution device 52 uniformly lays the pulp 30mm thick, sandwiched between the upper and lower filter cloths 53, and directly delivered to the pulp hydraulic device 56 between the pulp pressure filter plates 55 by the filter cloth traction device 54, and then gradually increased from 1MPa to 15MPa, with a net time of 60 seconds, during which part of the black liquor is discharged from both sides of the pulp pressure filter plates 55 through the filter cloth 53 under the pressure of the pulp hydraulic device 56 and flows into the black liquor recovery tank through the pipeline, and the pulp is pressure filtered into a pulp sheet with a dryness of 70%.

[0104] S6 washing and black liquor recovery: the pulp sheet with a dryness of 70% after pressure filtration in the pulp pressure filter 5 in S5 is delivered to the pulp sheet crushing device 6 for crushing and scattering, and then the loose pulp is sequentially delivered to the first-stage washing machine 81, the second-stage washing machine 82, and the third-stage washing machine 83 of the washing device 8 for three-stage washing, to remove residual liquor and dissolved lignin, improve the purity of the pulp, and further recover the black liquor in the pulp.

[0105] S7 screening and purification: the pulp after three-stage washing in S6 is delivered to the screening device 9 to remove undecomposed wood chips, coarse fiber bundles and impurities, so that the uniformity and cleanliness of the pulp meet the index requirements.

[0106] S8 bleaching: the pulp after screening and purification in S7 is delivered to the bleaching device 10 for bleaching treatment with chlorine dioxide, so that the whiteness meets the set requirements.

[0107] S9 concentration: the pulp after bleaching in S8 is delivered to the concentration device 11 for vacuum dewatering and concentration to a dryness of 3%, forming wet pulp suitable for pipeline transportation.

[0108] In the second specific embodiment of the preparation method of the pulp mechanical supercharging preparation system of the application, wood chips are used as the pulp preparation raw material, and chemical mechanical pulp preparation process is adopted, and the preparation method is similar to the previous embodiment, and the difference is only that:

[0109] In S3, the wood chip breaker 1 breaks and refines the wood chips to a particle size of 5mm.

[0110] In S4, the broken wood chips with a particle size of 5mm after breaking in the wood chip breaker 1 are put into the cooking device 2 and mixed with NaOH and Na2S liquor, and then soaked at normal pressure and a temperature interval of 90-100℃ for 10 minutes.

[0111] The slurry that has completed the cooking reaction in S5 is transported to the slurry filter press 5 for filtration at a pressure of 6 MPa and a net time of 10 seconds. The slurry is filtered into slurry sheets with a dryness of 30%.

[0112] The pulp sheet with a dryness of 30% in S6 is first transported to the pulping machine 7 for refining, and then the ground pulp is transported to the first-stage washing machine 81, the second-stage washing machine 82, the third-stage washing machine 83 and the fourth-stage washing machine 84 of the washing device 8 in sequence for four-stage washing to remove residual black liquor.

[0113] The pulp that has been screened and purified in S8 is transported to the bleaching device 10 for bleaching with hydrogen peroxide.

[0114] In a third specific embodiment of the method for preparing a mechanical pressurized pulp preparation system of the present invention, wood chips are used as pulping raw materials and a chemical pulping process is adopted. The preparation method is similar to the previous embodiment, with the only difference being that:

[0115] In S5, the slurry is first sprayed from the cooking device 2 to the spraying bin 3 and then transported from the spraying bin 3 to the slurry filter press 5 for filtration;

[0116] The slurry that has completed the cooking reaction in S5 is transported to the slurry filter press 5 for filtration at a pressure of 5 MPa and a net time of 300 seconds. The slurry is filtered into slurry sheets with a dryness of 60%.

[0117] The pulp pieces with a dryness of 60% in S6 are transported to the blade / hammer crusher 64 for crushing and breaking up, and washing water is added simultaneously.

[0118] In a fourth specific embodiment of the method for preparing a mechanical pressurized pulp preparation system of the present invention, wood chips are used as pulping raw materials and a chemical pulping process is adopted. The preparation method is similar to the previous embodiment, with the only difference being that:

[0119] S5 and S6 are performed in an interchangeable order, that is, the slurry after being cooked in the cooking device 2 is first washed by the first-stage washing machine 81 of the washing device 8 and then conveyed to the slurry filter press 5 for filtration at a pressure of 8 MPa and a net time of 60 seconds. After the slurry is filtered into slurry sheets with a dryness of 50%, it is sequentially conveyed to the second-stage washing machine 82, the third-stage washing machine 83, the fourth-stage washing machine 84 and the fifth-stage washing machine 85 of the washing device 8 to complete the entire washing process and meet the requirements of the residual index of the drug.

[0120] The above merely describes preferred embodiments of the present application, and is not intended to limit the present application in any form. Although the present application has been disclosed with the preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the technical solution of the present application, can make some changes or modifications to the above disclosed technical content to obtain equivalent embodiments with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the technical solution of the present application, shall still fall within the scope of the technical solution of the present application.

Claims

1. A mechanical pressurized pulp preparation system, comprising a pulper (1), a cooking device (2), a washing device (8), a screening device (9), a bleaching device (10), and a concentrating device (11), wherein the pulper, the cooking device, the washing device, the screening device, the bleaching device, and the concentrating device are sequentially connected and installed, and the washing device is composed of three to five stages of washing machines, characterized in that: It also includes a slurry filter press (5); the slurry filter press is connected and installed at the rear end of the cooking device or the front end of any one of the first three stages of the washing device.

2. The mechanical pressurized pulp preparation system according to claim 1, characterized in that: It also includes a spraying bin (3), and the slurry filter press is connected and installed at the rear end of the cooking device or the spraying bin and the front end of any one of the first three stages of the washing device.

3. The mechanical pressurized pulp preparation system according to claim 1, characterized in that: It also includes a pulping machine (7), and the pulp filter press is connected and installed at the rear end of the cooking device, the pulping machine, or the front end of any one of the first three stages of the washing machine of the washing device.

4. The mechanical pressurized pulp preparation system according to claim 1, characterized in that: It also includes a spraying bin (3) and a pulping machine (7), wherein the pulp filter press is connected and installed at the rear end of the cooking device or the spraying bin, the front end of the pulping machine or any one of the first three stages of the washing device.

5. The mechanical pressurized pulp preparation system according to any one of claims 1 to 4, characterized in that: The slurry filter press (5) comprises a filter press frame (51), a slurry distributing device (52), a filter cloth (53), a filter cloth traction device (54), a slurry filter press plate (55), and a slurry hydraulic device (56), wherein the slurry distributing device, the filter cloth traction device, and the slurry hydraulic device are connected and installed on the filter press frame, the slurry filter press plate is installed on the slurry hydraulic device, and the filter cloth is wound around and movably connected to the filter cloth traction device and passes through between the slurry filter press plates.

6. The mechanical pressurized pulp preparation system according to claim 1 or 2, characterized in that: It also includes a pulp sheet crushing device (6); the pulp sheet crushing device is connected and installed at the rear end of the pulp filter press and the front end of the washing device.

7. The mechanical pressurized pulp preparation system according to claim 3 or 4, characterized in that: It also includes a pulp sheet crushing device (6); the pulp sheet crushing device is connected and installed at the rear end of the pulp filter press, the washing device or the front end of the pulping machine (7).

8. The mechanical pressurized pulp preparation system according to claim 1 or 3, characterized in that: It also includes a solid-liquid pre-separation device (4); the solid-liquid pre-separation device is connected and installed at the rear end of the cooking device (2) and the front end of the slurry filter press (5).

9. The mechanical pressurized pulp preparation system according to claim 2 or 4, characterized in that: It also includes a solid-liquid pre-separation device (4); the solid-liquid pre-separation device is connected and installed at the rear end of the cooking device (2) or the spraying bin (3) and the front end of the slurry filter press (5).

10. The mechanical pressurized pulp preparation system according to claim 6 or 7, characterized in that: The pulp sheet crushing device (6) includes a double roller shredder (61) or / and a double screw conveyor (62), a chain crusher (63) or a blade / hammer crusher (64), and a paddle mixer (65).

11. The mechanical pressurized pulp preparation system according to claim 8 or 9, characterized in that: The solid-liquid pre-separation device (4) is a belt separator (41) or a spiral screen separator (42).

12. A method for preparing a pulp mechanical pressurization preparation system according to any one of claims 1 to 11, characterized in that: It includes the following steps: S1 Preparation: Prepare wood chips that have been freed of debris, sand and other impurities or have completed storage, fermentation and balanced moisture; S2 starts the system: respectively starts the pulper (1), the cooking device (2), or / and the spray bin, the pulp filter press (5), or / and the refiner, the washing device (8), the screening device (9), the bleaching device (10), and the concentrating device (11), and puts the system into a startup standby state; S3 wood chip crushing: the wood chips prepared in S1 are put into the pulper (1) to be crushed to a particle size of 5 to 20 mm; S4 cooking: the wood chips crushed by the pulper in S3 are put into the cooking device and mixed with the chemical liquid to react at a preset temperature and pressure; S5 slurry filtration and liquid recovery: The slurry that has completed the cooking reaction in S4 is transported to the slurry filter press (5) for filtration. The slurry filter press (5) evenly spreads and clamps the slurry and directly pulls and transports it to the filtration area for filtration at a pressure of 1 to 15 MPa. Part of the black liquor is discharged from the slurry filter press (5) under pressure and flows into the black liquor recovery tank through a pipeline. The slurry is filtered into a slurry sheet with a dryness of 30% to 70%. S6 washing and waste liquid recovery: the slurry sheets with a dryness of 30% to 70% after filtering by the slurry filter press (5) in S5 are transported to the washing device (8) for three to five stages of reverse washing to improve the purity of the slurry and further recover the black liquor in the slurry; S7 screening and purification: the pulp washed in S6 is transported to the screening device (9) to remove undigested fiber bundles and impurities, thereby improving the cleanliness of the pulp; S8 bleaching: the pulp that has been screened and purified in S7 is transported to the bleaching device (10) for bleaching with chemicals to improve whiteness; S9 concentration: The pulp bleached in S8 is transported to the concentration device (11) to be concentrated to a dryness of about 3%, thereby forming wet pulp suitable for pipeline transportation.

13. The method for preparing a pulp mechanical pressurization preparation system according to claim 12, further characterized by: Slurry filtration and liquid recovery in S5: The slurry that has completed the cooking reaction in S4 is transported to the slurry distribution device (52) of the slurry filter press (5), and the slurry distribution device (52) and the filter cloth traction device (54) are started and operated. The slurry distribution device (52) evenly spreads and clamps the slurry on the filter cloth (53) and directly traction-transports the slurry to the bottom of the slurry hydraulic device (56) and between the slurry filter press plates (55) through the filter cloth traction device (54) for filtration at a pressure of 1 to 15 MPa. Part of the black liquor passes through the filter cloth (53) under the pressure of the slurry hydraulic device (56) and is discharged from both sides of the slurry filter press plates (55) and flows into the black liquor recovery tank through the pipeline. The slurry is filtered into slurry sheets with a dryness of 30% to 70%.

14. The method for preparing a pulp mechanical pressurization preparation system according to claim 13, further characterized by: In S5, the slurry is first sprayed from the cooking device (2) to the spraying bin (3) and then transported from the spraying bin (3) to the slurry filter press (5) for filtration; In S5, the slurry is filtered between the slurry filter press plates (55) at a pressure of 1 to 15 MPa for a net time of 10 to 300 seconds; Slurry flakes with a dryness of 30% to 70% in S6 are transported to the washing device (8) for washing and then crushed and dispersed by the slurry flake crushing device; Slurry sheets with a dryness of 30% to 70% in S6 are transported to the washing device (8) for washing, broken up by the pulp sheet breaking device (6), and then transported to the refiner (7) for refining; S5 and S6 are performed in an interchangeable order, and the slurry after cooking is first washed by the first, second or third stage washing machine of the washing device (8) and then filtered; The pulp flakes with a dryness of 30% to 70% in S6 are transported to the pulp flake crushing device (6) for crushing and breaking up, or / and transported to the pulping machine (7) for pulping and simultaneously adding washing water.

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