Pulp dipping and squeezing system

Abstract

The utility model discloses a pulp dipping and squeezing system which comprises a dipping liquid metering tank, a dipping barrel and a diaphragm type filter press which are sequentially communicated, a water inlet of the diaphragm type filter press is further communicated with a water tank, and a high-pressure water pump is arranged on a water inlet pipeline of the water tank and the diaphragm type filter press. The liquid discharging end of the diaphragm type filter press is communicated with a liquid pressing tank, and the outlet end of the liquid pressing tank is communicated with the steeping liquid metering tank. According to the utility model, the diaphragm type filter press is used, and the filter cloth is used for replacing the filtering effect of meshes of a mesh compression roller type press, so that the problem of wet materials after the meshes are blocked is completely eliminated, the slurry porridge can be recycled by only filling a pipeline between the slurry porridge pump and the diaphragm type filter press, the consumption of raw materials is reduced, the waste can be avoided, and the production cost is reduced. Therefore, the method is also suitable for batch-type small-batch production with fewer raw materials.

Description

TECHNICAL FIELD

[0001] The utility model relates to viscose fibre preparation technical field, especially a pulp dip squeezing system. BACKGROUND

[0002] In viscose fibre production, pulp is formed by alkali immersion. The pulp squeezing equipment mainly adopts mesh hole squeezing roller. The structure of mesh hole squeezing roller is shown in the figure Figure 1 , which mainly includes pulp tank 200, frame 100, front squeezing roller 300, rear squeezing roller 400, front scraper 500, rear scraper 600, front shower 700, rear shower 800, exhaust hood 900 and transmission part. Squeezing is completed by two front and rear squeezing rollers. The squeezing roller is mesh hole type, and the width is generally about 1800mm. The two squeezing rollers rotate synchronously and reversely. The squeezing roller is supported by double-row centripetal roller bearing. The roller surface is stainless steel hole plate with a hole diameter of about 1mm. The roller interior is hollow roller with several reinforcing ribs. Multiple holes are arranged on both sides of the roller to facilitate the backflow of the squeezing alkali. Gaskets are arranged between the squeezing roller bearing seats and between the pressing plate and the bearing to adjust the distance between the squeezing rollers to 0-24mm. Adjustable plastic scrapers are arranged above the squeezing roller to peel off the fiber layer. The front squeezing roller 300 is provided with the front scraper 500 on one side. The rear scraper 600 is arranged between the front squeezing roller 300 and the rear squeezing roller 400. The pulp tank side plate below the squeezing roller and both ends of the squeezing roller are provided with sealing rubber strips and hollow rubber rings. The hollow rubber rings are sealed by compressed air to form a closed space between the two squeezing rollers and the pulp tank 200 below. Thus, two spaces are formed from the pulp entrance 1000 below and the alkali backflow area on both sides of the squeezing roller, which do not interfere with each other. A row of nozzles is arranged horizontally on the circumferential surface of the front and rear squeezing rollers, which are the front shower 700 and the rear shower 800 respectively. The surface of the squeezing roller is washed with alkali to ensure the smoothness of the mesh hole.

[0003] The working process is as follows: the alkali cellulose pulp enters the pulp tank 200 from the pulp entrance 1000 below at a constant pressure. After the pulp tank is filled, the pulp is squeezed into the squeezing roller. The two squeezing rollers drive the pulp to pass between them, and the pulp is fully compressed. The squeezed alkali enters the roller interior through the stainless steel mesh hole on the roller surface and flows out from both ends of the roller. The squeezed alkali cellulose is squeezed upwards and scraped off by the rear scraper 600 on the front squeezing roller 300 and rotates with it. Then, the squeezed alkali cellulose is scraped up by the front scraper 500 and discharged along the discharge chute. The bearing seat position of the squeezing roller is provided with a pressure sensor to feed back the pressure signal between the two squeezing rollers to the pulp pump and the squeezing roller. The speed of the pulp pump or the squeezing roller is adjusted to ensure the constant pressure between the two squeezing rollers.

[0004] With the progress of viscose fiber production technology, and the industry gradually to green low-carbon transformation development, the production capacity of the press put forward higher requirements, the traditional mesh press roll type press has gradually unable to meet the demand of technology update. On the one hand, from the point of view of reducing production cost, hope that the degree of alkali fiber press higher, because can improve the recovery rate of alkali, reduce the alkali consumption of immersion process. On the other hand, the traditional mesh press roll type press needs to be matched with high power press roll motor and pulp pump motor, the energy consumption is high, need to seek new more energy efficient way of pressing. In addition, the traditional mesh press roll type press also exposed the following shortcomings in the process of use:

[0005] Shortcomings: 1. mesh type press roll because of the small diameter of the mesh, easy to be blocked by alkali cellulose, impurities. Sometimes in the press out of the alkali cellulose can see the wet patch or block, this is due to the mesh of alkali cellulose moisture can not be excluded through the mesh, just formed wet patch. Even if the press roll both sides have shower nozzle, in the actual production process, the effect of shower cleaning is not ideal, still need to use high pressure flushing pump for flushing. In addition, the nozzle is easy to be blocked by alkali scale, need to use special tools to dredge, and often dredging operation will damage the nozzle channel, lead to alkali column rather than scattered spray, cleaning effect is greatly reduced.

[0006] 2. pulp tank pressure has a great influence on the moisture content of the press after alkali fiber, before the pulp into the two press rolls between the press, first need to fill the pulp tank under the press roll, to ensure enough and stable press roll into the pulp pressure, to ensure the degree of alkali fiber press qualified. Because the mesh press roll type press pulp tank volume is large, in the equipment start and stop stage, the pulp tank filled with a lot of pulp, so a lot of pulp without press loss, so the mesh press roll type press is not suitable for alkali cellulose intermittent small batch press production process.

[0007] 3. the pulp treatment capacity of mesh press roll type press, can be adjusted by adjusting the distance between the front and rear press roll, but must be in the case of parking repair, the equipment is disassembled to adjust the press roll spacing, the operation is very inconvenient.

[0008] 4. the traditional mesh press roll type press roll pressure is limited to 1.0 bar, so the press out of the alkali fiber content of methyl cellulose also has an upper limit. The purpose is to avoid the high pressure of pulp tank, lead to the damage of the sealing element of pulp tank, cause the pulp splash accident. Its pressure sensor and pulp pump interlock, pressure rises to the upper limit of the set, the pulp pump is automatically stopped.

[0009] 5. At the same pulp concentration, the fluctuation of the pressing pressure causes the instability of the alkali cellulose after pressing (low pressing pressure makes low methylene and high alkali, high pressing pressure makes high methylene and low alkali), which makes the instability of the cellulose polymerization degree after aging, directly causes the instability of the viscose viscosity, and affects the quality of the viscose. The pressing pressure can be adjusted through feedback, but the adjustment process has hysteresis, and the pressure fluctuation cannot be completely eliminated.

[0010] 6. The change of the pulp concentration has a great influence on the pressing effect. The low pulp concentration will cause the fast pulp flow speed between the two pressing rollers, low pressing pressure, and the over-wet alkali cellulose after pressing. The high pulp concentration will cause the pressing difficulty, the increase of the pressing machine power and the pulp tank pressure, and easily cause the equipment damage. Specifically, when the pulp concentration is too low, in one case, the material will be directly sprayed from the two pressing rollers, and cannot be pressed; in another case, the pulp consistency ensures that the material will not be sprayed from the rollers, but the leakage of the pulp will be caused from the sealing of the pressing roller, if not found in time, the leakage pulp will block the pressing liquid return pipeline, causing the pressing machine to not run normally, and the leakage pulp will produce waste glue once entering the aging and yellowing system with the alkali cellulose. When the pulp concentration is too high and the pressure is not adjusted in time, the alkali cellulose after pressing is easily squeezed between the two pressing rollers of the pressing machine, causing the material blocking and the shutdown of the pressing machine.

[0011] 7. In actual production, the pressing roller net skin is easy to be damaged and fall off, and the iron fragments falling off will enter the subsequent section with the alkali, especially enter the yellowing machine, which is easy to cause the explosion accident, and has an adverse effect on the safety production. Practical new type content

[0012] In view of the above problems, the purpose of the present application is to provide a pulp impregnation and pressing system to solve the problems of the easy clogging of the mesh hole of the existing mesh hole pressing machine, the waste of the pulp, the high energy consumption, and the influence of the change of the pulp concentration on the pressing effect.

[0013] The present application is realized as follows:

[0014] A pulp impregnation and pressing system, comprising a dipping liquid metering tank, a dipping barrel and a diaphragm filter press which are sequentially and communicatively connected, the water inlet of the diaphragm filter press is further communicatively connected with a water tank, a high-pressure water pump is arranged on the water inlet pipeline of the diaphragm filter press, the liquid discharge end of the diaphragm filter press is communicatively connected with a liquid pressing tank, and the outlet end of the liquid pressing tank is communicatively connected with the dipping liquid metering tank.

[0015] Further, the air compressor is further included, the diaphragm filter press is provided with a first air inlet, a second air inlet, a first air outlet and a second air outlet, the air compressor is connected with the first air inlet and the second air inlet through a first air pipe and a second air pipe respectively, the first air outlet is connected with the immersion barrel through a third air pipe, the second air outlet is connected with the liquid pressure tank through a fourth air pipe, and control valves are arranged on the connecting pipes of the first air pipe, the second air pipe, the third air pipe and the fourth air pipe.

[0016] Further, the immersion barrel is connected with the diaphragm filter press through a first liquid pipe, and a slurry pump is arranged on the first liquid pipe.

[0017] Further, an electric contact pressure gauge is arranged on the first liquid pipe, and the electric contact pressure gauge is electrically connected with the slurry pump.

[0018] Further, the liquid pressure tank is connected with the immersion liquid measuring tank through a second liquid pipe, a liquid pressure pump and an accumulated flow meter are arranged on the second liquid pipe, and the liquid pressure pump is electrically connected with the accumulated flow meter.

[0019] Further, the immersion liquid measuring tank is provided with a first liquid inlet for adding dilute lye and a second liquid inlet for adding concentrated lye, a first motor is fixedly arranged on the top of the immersion liquid measuring tank, a first stirring paddle is fixedly arranged at the output end of the first motor, and the first stirring paddle penetrates through the top of the immersion liquid measuring tank and extends into the interior thereof.

[0020] Further, a heating circulating machine is further arranged outside the immersion liquid measuring tank.

[0021] Further, a first feeding port for adding slurry is arranged on the immersion barrel, a second motor is fixedly arranged on the top of the immersion barrel, a second stirring paddle is fixedly connected to the output end of the second motor, and the second stirring paddle penetrates through the top of the immersion barrel and extends into the interior thereof.

[0022] The slurry immersion and pressing system has the advantages that:

[0023] 1. The slurry immersion and pressing system uses the diaphragm filter press, the filter cloth is used for filtering instead of the filtering effect of the mesh hole press roller type pressing machine, the alkali fiber humidity after pressing is uniform, the filter cloth is convenient to replace and clean, and the problem of wet material caused by the mesh hole press roller type pressing machine is completely eliminated.

[0024] 2. Compared with the mesh hole press roller type pressing machine which needs to fill the slurry tank for pressure filling, the slurry immersion and pressing system only needs to fill the pipe between the slurry immersion barrel and the diaphragm filter press with slurry, the slurry can be recycled through back blowing, the raw material consumption is reduced, waste can be avoided, and therefore, the system is suitable for intermittent small-batch production with less raw material.

[0025] 3. The pulp processing capacity can be adjusted by increasing or decreasing the number of filter plates, which is very convenient.

[0026] 4. The diaphragm filter press is used for pulp pressing, the pressing degree of pulp with different concentrations can be controlled by adjusting the feeding amount of the press, the pressing time and the pressure of the high-pressure water for secondary pressing, the control mode is simple and convenient, and the disadvantages of the traditional mesh hole press roller press, such as difficult adjustment of the pressing roller gap, narrow range of suitable pulp concentration and low pressing degree, are overcome.

[0027] 5. The pulp with too low or too high concentration can be normally pressed, and the disadvantages of the mesh hole press roller press, such as easy material blockage of high-concentration pulp and easy leakage of low-concentration pulp, are overcome.

[0028] 6. The pressing degree of the diaphragm filter press is obviously improved compared with that of the traditional mesh hole press roller, which is beneficial to reducing the consumption of impregnation alkali and power consumption, and the alkali content in the pressed alkali fiber is less, so that the consumption of raw material carbon disulfide in the subsequent yellowing reaction can be reduced, the byproduct is reduced, the raw material cost is reduced, and the viscose quality is improved. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a structural view of the mesh hole press roller press of the prior art;

[0030] Figure 2 It is a process flow chart of the utility model;

[0031] Figure 3 It is a schematic view of the filter plate of the diaphragm filter press of the utility model;

[0032] Figure 4 It is a power consumption comparison chart of two pressing modes under different feeding pulp concentration conditions of the utility model;

[0033] Figure 5 It is a power consumption comparison chart of two pressing modes under different discharging alkali fiber content conditions of the utility model.

[0034] Explanation of the reference signs:

[0035] 1. Impregnation liquid metering tank; 101, first liquid inlet; 102, second liquid inlet; 103, third liquid inlet; 104, first motor; 105, first stirring paddle; 106, glass tube liquid level meter; 107, heating circulating machine; 108, jacket;

[0036] 2. Impregnation barrel; 201, first feeding port; 202, second motor; 203, second stirring paddle;

[0037] 3, diaphragm filter press; 300, filter plate; 3001, feed small channel; 301, first air inlet; 302, second air inlet; 303, first air outlet; 304, second air outlet; 305, first air pipe; 3051, second valve; 306, second air pipe; 3061, third valve; 307, third air pipe; 3071, first valve; 308, fourth air pipe; 3081, fourth valve; 309, fifth air pipe;

[0038] 4, water tank; 5, high-pressure water pump; 6, liquid pressure tank; 7, second liquid pipe; 701, liquid pressure pump; 702, cumulative flow meter; 8, first liquid pipe; 801, pulp pump; 802, electric contact pressure gauge; 9, water inlet pipe; 10, pressure relief pipe; 11, air compressor; 12, hydraulic station; 13, electrical control box;

[0039] Prior art: 100, rack; 200, pulp tank; 300, front press roller; 400, rear press roller; 500, front scraper; 600, rear scraper; 700, front shower; 800, rear shower; 900, exhaust hood; 1000, pulp inlet. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. In the following description, a large number of specific details are set forth in order to give a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0041] As Figure 2 shown is a pulp impregnation and press system, comprising an impregnation liquid metering tank 1, an impregnation barrel 2 and a diaphragm filter press 3 which are sequentially and communicatively arranged, the water inlet of the diaphragm filter press 3 is further communicatively provided with a water tank 4, the water tank 4 is provided with a high-pressure water pump 5 on the water inlet pipe 9 of the diaphragm filter press 3, the liquid outlet end of the diaphragm filter press 3 is communicatively provided with a liquid pressure tank 6, and the outlet end of the liquid pressure tank 6 is in communication with the impregnation liquid metering tank 1.

[0042] In this embodiment, the impregnation liquid measuring tank 1 is arranged above the impregnation barrel 2, and the outlet of the impregnation liquid measuring tank 1 is communicated with the top of the impregnation barrel 2. The material of the impregnation liquid measuring tank 1 is 304 stainless steel, and the impregnation liquid measuring tank 1 is respectively provided with a first liquid inlet 101 for adding dilute lye and a second liquid inlet 102 for adding concentrated lye. The first liquid inlet 101 and the second liquid inlet 102 are respectively communicated with a dilute lye storage tank and a concentrated lye storage tank (not shown in the figure) through pipelines. The second liquid inlet 102 can be provided as a hand hole, and the concentrated lye can be manually added into the impregnation liquid measuring tank 1 through the second liquid inlet 102. The top of the impregnation liquid measuring tank 1 is also provided with a third liquid inlet 103 for adding press liquid, and the press liquid tank 6 is communicated with the impregnation liquid measuring tank 1 through a second liquid pipeline 7. The inlet end of the second liquid pipeline 7 is communicated with the outlet of the press liquid tank 6, and the outlet end of the second liquid pipeline 7 is communicated with the third liquid inlet 103 of the impregnation liquid measuring tank 1, so as to transport the filtered press liquid into the impregnation liquid measuring tank 1 and avoid energy waste. The second liquid pipeline 7 is provided with a press liquid pump 701 and an accumulated flow meter 702, and the press liquid pump 701 is electrically connected with the accumulated flow meter 702. The inlet of the press liquid pump 701 is connected with the outlet of the press liquid tank 6, and the outlet of the press liquid pump 701 is connected with the impregnation liquid measuring tank 1. The accumulated flow meter 702 is interlocked with the press liquid pump 701, and the cumulative delivery amount of the press liquid can be set. When the total amount of the press liquid delivered by the press liquid pump 701 reaches the set value, the press liquid pump 701 automatically stops.

[0043] The top of the impregnation liquid measuring tank 1 is fixedly provided with a first motor 104, and the output end of the first motor 104 is fixedly provided with a first stirring paddle 105. The first stirring paddle 105 penetrates through the top of the impregnation liquid measuring tank 1 and extends into the interior thereof, and the first stirring paddle 105 is used for fully stirring and mixing the solution in the impregnation liquid measuring tank 1. The impregnation liquid measuring tank 1 is also provided with a glass tube liquid level meter 106, and the volume of the added dilute lye, concentrated lye and press liquid can be measured by observing the liquid level of the glass tube liquid level meter 106. The outside of the impregnation liquid measuring tank 1 is also provided with a heating circulating machine 107, and the outer wall of the impregnation liquid measuring tank 1 is fixedly provided with a jacket 108. The jacket 108 and the impregnation liquid measuring tank 1 are heated by the heating circulating machine 107 with water or heat conducting oil as medium.

[0044] In this embodiment, the material of the impregnation barrel 2 is 304 stainless steel, and the impregnation barrel 2 is provided with a first feeding port 201 for adding pulp. The first feeding port 201 can be provided as a hand hole, and the pulp can be manually added through the first feeding port 201. The top of the impregnation barrel 2 is fixedly provided with a second motor 202, and the output end of the second motor 202 is fixedly connected with a second stirring paddle 203. The second stirring paddle 203 penetrates through the top of the impregnation barrel 2 and extends into the interior thereof, and the second stirring paddle 203 is used for fully stirring and mixing the pulp and the impregnation liquid in the impregnation barrel 2 and forming pulp porridge.

[0045] The impregnation barrel 2 is connected with the diaphragm filter press 3 through a first liquid pipeline 8, and a slurry pump 801 is arranged on the first liquid pipeline 8. An electric contact pressure gauge 802 is further arranged on the first liquid pipeline 8, and the electric contact pressure gauge 802 is arranged close to the liquid inlet of the diaphragm filter press 3, and the electric contact pressure gauge 802 is electrically connected with the slurry pump 801. The slurry pump 801 is a common three-vane cam rotor pump, and the material is 316 stainless steel. The slurry pump 801 can be variable frequency speed regulation, and the slurry pump 801 is overpressure interlocked with the electric contact pressure gauge 802 of the liquid inlet of the diaphragm filter press 3, and the overpressure value can be set to protect the diaphragm filter press 3. When the filtration starts, the slurry is pushed into each filter chamber of the diaphragm filter press 3 by the slurry pump 801, and the pressure generated by the slurry pump 801 is used for solid-liquid separation.

[0046] In the embodiment, the diaphragm filter press 3 can adopt a mature product sold on the market, and the product model is not limited. The diaphragm filter press 3 includes a rack, a hydraulic station 12, a filter system and an electrical control box 13. The rack is a basic component of the filter press, mainly composed of a girder, a compression plate, a thrust plate, a filter plate, a diaphragm filter plate, filter cloth, a hydraulic system and the like. The filter system includes a plurality of filter plates, filter cloth and pressing diaphragm plates, the filter plate is covered by the filter cloth, and the filter plate and the filter cloth are arranged alternately. The filtered material enters each filter chamber from the feed hole, and the solid particles are intercepted in the filter chamber because the particle size is larger than the pore size of the filter cloth, and the filtrate is discharged from the liquid outlet hole below the filter plate. The structure of the filter plate 300 is shown in Figure 3 The hydraulic station 12 includes a motor, an oil pump, an overflow valve, a pressure gauge, an oil circuit, a compression plate and an oil tank. The electrical control box 13 is the control center of the diaphragm filter press 3, which controls the whole diaphragm filter press 3 by controlling the hydraulic station 12. The working principle of the diaphragm filter press 3 mainly includes feeding and pre-pressing, filtering, pressing, flushing, liquid removal and diaphragm extrusion. The structure and working principle of the diaphragm filter press 3 are all prior art, and will not be described here.

[0047] The water inlet of the diaphragm filter press 3 is further connected with a water tank 4, and a high-pressure water pump 5 and a control valve (not marked in the figure) are arranged on the water inlet pipeline 9 of the diaphragm filter press 3. By introducing high-pressure water into the filter assembly of the diaphragm filter press 3, the filter cake is further pressed to reduce the water content. Preferably, the water tank 4 and the water inlet pipeline 9 are further connected with a pressure relief pipeline 10, and the pressure relief pipeline 10 is also provided with a control valve. The pressure relief pipeline 10 is arranged to release the water pressure in the diaphragm chamber of the diaphragm filter press 3.

[0048] The liquid discharge end of the diaphragm filter press 3 is communicated with a liquid pressing tank 6, and the outlet end of the liquid pressing tank 6 is communicated with the immersion liquid metering tank 1.

[0049] The pulp impregnation and pressing system also comprises an air compressor 11, and the diaphragm filter press 3 is provided with a first air inlet 301, a second air inlet 302, a first air outlet 303 and a second air outlet 304. The first air inlet 301 is communicated with the liquid inlet thereof, and the second air inlet 302 is communicated with the liquid discharge port thereof. The first air tube 305 and the third air tube 307 are communicated through a fifth air tube 309, and the fifth air tube 309 is located at the end of the air compressor 11 away from the liquid inlet.

[0050] The air compressor 11 is started, and then compressed air is introduced into the diaphragm filter press 3 for back blowing. Specifically, the first valve 3071 and the second valve 3051 are opened, and the compressed air blows back the pulp in the liquid inlet channel of the diaphragm filter press 3 through the first air tube 305, the liquid inlet channel of the diaphragm filter press 3, the fifth air tube 309 and the third air tube 307 in sequence.

[0051] The working process of the pulp impregnation and pressing system comprises the following steps:

[0052] S1, in the impregnation liquid metering tank 1 is equipped with impregnation liquid, namely with dilute lye, press liquid and concentrated lye mixed in the appropriate proportion, in this embodiment, in the impregnation liquid metering tank 1 is mixed with 200L of impregnation liquid with sodium hydroxide concentration of 230g / L, for pulp impregnation. Specifically, it is divided into the following two cases:

[0053] A, before the first start (with dilute lye and concentrated lye to prepare impregnation liquid)

[0054] According to the concentration of dilute lye, concentrated lye, the amount of dilute lye and concentrated lye required to prepare a tank of impregnation liquid is calculated.

[0055] The amount of dilute lye and concentrated lye is calculated according to the following formula:

[0056] 210*N (amount of dilute lye) + 432*Y (amount of concentrated lye) = 230*(N+Y)

[0057] N+Y=200L (impregnation liquid amount)

[0058] N=182L, Y=18L is calculated

[0059] Add dilute lye and concentrated lye to the impregnation liquid metering tank 1, close the dilute lye inlet manual valve after feeding, start the first stirring paddle 105 to stir, open the heating circulating machine 107, and heat the impregnation liquid to not less than 50℃, so that the pulp reacts with the alkali in the impregnation liquid during the impregnation process to generate alkali fiber, and then adjust the heating circulating machine 107 setting temperature for heat preservation.

[0060] B, normal operation (use press liquid, concentrated lye, dilute lye to prepare impregnation liquid)

[0061] According to the concentration of press liquid and the amount of press liquid, the amount of concentrated lye and dilute lye required is calculated. When the concentration of impregnation liquid changes, the amount of dilute lye and concentrated lye is adjusted accordingly.

[0062] The amount of dilute lye and concentrated lye is calculated according to the following formula:

[0063] c (press liquid concentration) *X (press liquid amount) + 210*N (dilute lye amount) + 432*Y (concentrated lye amount) = 230*(N+Y)

[0064] X+N+Y=200L (impregnation liquid amount)

[0065] The volume value of the pressurized liquid is set on the cumulative flow meter 702, the pressurized liquid pump 701 is started to deliver the pressurized liquid to the impregnation liquid metering tank 1 until the cumulative amount reaches the set value, the pressurized liquid pump 701 is automatically stopped, and the pump outlet hand valve is closed. The dilute lye and the concentrated lye are added to the impregnation liquid metering tank 1, after the addition is completed, the dilute lye inlet hand valve is closed, the stirring is started, the heating circulator 107 is opened, the impregnation liquid is heated to not less than 50℃, and then the heating circulator 107 is adjusted to set the temperature for heat preservation.

[0066] S2, the exhaust valve of the impregnation barrel 2 and the charging port communicated with the impregnation liquid metering tank 1 are opened, the prepared impregnation liquid is all fed into the impregnation barrel 2, and the pulp is added to the impregnation barrel 2, the weighed pulp can be manually poured into the impregnation barrel 2 through the first inlet 201, and the absolute dry weight of the pulp is 10 kg. The first inlet 201 can be provided as a hand hole to facilitate manual addition of the pulp. In order to improve the reaction performance of the pulp, 0.03%-0.2% V388 additive is manually added to the impregnation barrel 2. The mixing state of the materials in the impregnation barrel 2 is observed, the first inlet 201 is closed after normal, the second motor 202 is started, the second motor 202 rotates to drive the second stirring paddle 203 to rotate, and the second stirring paddle 203 is used to mix and stir the pulp and the impregnation liquid in the impregnation barrel 2 to form pulp porridge. The stirring reaction is 30-40 minutes, the temperature of the impregnation liquid is about 50-55℃, the volume of the impregnation liquid and the weight of the pulp are calculated according to 1 kg of absolute dry pulp corresponding to 20 L of impregnation liquid.

[0067] S3, the pulp porridge pump 801 is started to deliver the pulp porridge in the impregnation barrel 2 to the diaphragm filter press 3 for primary pressing, the excess lye is pressed out, and the pressurized liquid flows into the pressurized liquid tank 6. During the primary pressing, the pulp inlet pressure is less than or equal to 0.8 Mpa.

[0068] S4, after the pulp inlet is completed, the pulp porridge pump 801 is closed, the valves on the first air pipe line 305 and the third air pipe line 307 are opened, the air compressor 11 is started, the compressed air passes through the first air pipe line 305, the liquid inlet channel of the diaphragm filter press 3, the fifth air pipe line 309 and the third air pipe line 307 in sequence, and the pulp porridge in the liquid inlet channel of the diaphragm filter press 3 is backblown to the impregnation barrel 2. Then the valve on the third air pipe line 307 is closed, the compressed air passes through the first air inlet 301, the first air outlet 303 and the material inlet small channel 3001 in sequence to blow the pulp porridge in the material inlet small channel 3001 of the filter plate 300 of the diaphragm filter press 3 into the filter cake, and the pressurized liquid flows into the pressurized liquid tank 6.

[0069] S5, the air compressor 11 is closed, the valve on the first air pipe line 305 is closed, the high-pressure water pump 5 is started, and the high-pressure water is injected into the diaphragm filter press 3 for secondary pressing, the pressure of the secondary pressing is 0.5 MPa-2.0 MPa, and the pressurized liquid flows into the pressurized liquid tank 6.

[0070] S6, after the second squeezing is completed, i.e. when the flow of squeezed filtrate is extremely small, the control valve on the water inlet pipeline 9 is closed, the control valve on the pressure relief pipeline 10 is opened, the water pressure in the diaphragm chamber of the diaphragm filter press 3 is relieved, the valve on the second air pipeline 306 is opened, the control valve on the connecting pipeline between the second air pipeline 306 and the fourth air pipeline 308 is closed, i.e. the third valve 3061 is opened and the fourth valve 3081 is closed, and the air compressor 11 is started, so that compressed air passes through the second air inlet 302 and the second air outlet 304 in sequence and blows the residual filtrate in the discharge pipeline of the diaphragm filter press 3 into the liquid press tank 6.

[0071] S7, the air compressor 11 is closed, the hydraulic station 12 is controlled to act so as to loosen the pressing plate, and the squeezed alkali fiber filter cake is discharged from the filter chamber of the diaphragm filter press 3. The indexes of the squeezed alkali cellulose product are as follows: the content of the first kind of cellulose is 30%-35%, and the content of caustic soda is 13.5%-14.5%.

[0072] In view of the use effects of the traditional mesh hole press roller type press and the diaphragm filter press 3 of the embodiment, the following experiments are conducted. In the embodiment, the power consumptions of the two types of presses are compared. The power consumption of the traditional mesh hole press roller type press includes the power consumptions of the pulp pump 801 and the press roller, and the power consumption of the diaphragm filter press includes the power consumptions of the pulp pump 801 and the high-pressure water pump 5. Because the working principles of the two types of presses are different, the pressure data of the two types of presses only serve as auxiliary explanations, and the two types of pressing processes cannot be judged by comparison of the data.

[0073] Embodiment 1

[0074] Under different pulp concentrations, the squeezing pressure is adjusted so that the content of the first kind of cellulose in the squeezed alkali fiber reaches 30%, and the power consumptions of the two types of presses are compared. The specific experimental data are shown in Table 1.

[0075] Table 1: Squeezing power of the two types of presses when the content of the first kind of cellulose is 30% and the pulp concentration is different

[0076] Pulp consistency 3.0％ 3.5％ 4.0％ 4.5％ 5.0％ 5.5％ 6.0％ 6.5％ 7.0％ 7.5％ 8.0％ Mesh press power consumption (kWh / ton of alkali fiber) / 25.45 20.48 17.65 15.37 14.66 13.46 12.93 12.54 12.06 11.77 Diaphragm filter press power consumption (kWh / ton of alkali fiber) 9.87 8.96 8.03 7.24 6.51 6.23 6.03 5.72 5.59 5.48 5.37 Mesh press pressure (bar) Spray 0.62 0.59 0.57 0.56 0.56 0.55 0.53 0.52 0.52 0.51 Diaphragm filter press pressure (bar) 0.73 0.73 0.73 0.73 0.73 0.73 0.73 0.73 0.73 0.73 0.73

[0077] When the pulp concentration is less than or equal to 3.0%, the material of the mesh hole press roller type press is directly sprayed out from between the two press rollers and cannot be squeezed, but the diaphragm filter press of the embodiment can be used for squeezing. As shown in Table 1, under different pulp concentrations, the power consumption of the diaphragm filter press is far lower than that of the mesh hole press roller type press.

[0078] Embodiment 2

[0079] Under the condition of different pulp concentration, by adjusting the pressing pressure, the content of methyl cellulose in the alkali fiber pressed out is 35%, and the power consumption of the two pressing modes is compared. The specific experimental data is shown in Table 2.

[0080] Table 2 Pressing power of two pressing modes when the content of methyl cellulose is 35% under different pulp concentrations

[0081]

[0082]

[0083] When the pulp concentration is less than or equal to 3.5%, the material of the mesh hole press roller type press machine is directly sprayed out from between the two pressing rollers and cannot be pressed, but the utility model can be pressed. As shown in Table 3, under the condition of different pulp concentrations, the power consumption of the diaphragm type filter press is much lower than that of the mesh hole press roller type press machine.

[0084] Figure 4 The figure is a comparison of the power consumption of the mesh hole press roller type press machine and the diaphragm type filter press under the condition of different feeding pulp concentrations (pulp concentration) in Example 1 and Example 2. In the figure, the mesh roller press machine is a traditional mesh hole press roller type press machine, and the plate block press machine is the diaphragm type filter press in the utility model. From the figure, it can be seen that under the condition of different pulp concentrations, the power consumption of the diaphragm type filter press is much lower than that of the mesh hole press roller type press machine. Figure 4

[0085] Example 3

[0086] Using pulp raw material with a concentration of 5%, by adjusting the pressing pressure, alkali fiber with different methyl cellulose contents is obtained, and the power consumption of the two pressing modes is compared. The specific experimental data is shown in Table 3.

[0087] Table 3 Pressing power of two pressing modes when the pulp concentration is 5% and the alkali fiber with different methyl cellulose contents is obtained

[0088] MFC content 30.0％ 31.0％ 32.0％ 33.0％ 34.0％ 35.0％ 36.0％ 37.0％ 38.0％ 39.0％ 40.0％ Mesh press power consumption (kWh / ton of alkali fiber) 15.37 17.97 19.51 20.23 21.66 22.91 24.29 / / / / Diaphragm filter press power consumption (kWh / ton of alkali fiber) 6.51 7.11 7.82 8.70 10.50 11.80 12.26 13.70 15.35 18.05 20.48 Mesh press pressure (bar) 0.56 0.59 0.63 0.68 0.74 0.81 0.90 Overpressure Overpressure Overpressure Overpressure Diaphragm filter press pressure (bar) 0.73 0.79 0.87 0.96 1.06 1.17 1.30 1.45 1.63 1.85 2.08

[0089] As shown in Table 3, when the content of methyl cellulose is greater than 36%, the pressure of the mesh hole press roller type press machine has approached the upper limit, and it is impossible to obtain alkali fiber products with a content of methyl cellulose of more than 37% by increasing the pressing pressure, while the diaphragm type filter press can continue to press to obtain alkali fiber products with a higher content of methyl cellulose. Moreover, within the range of the content of methyl cellulose in this embodiment, under the condition of obtaining alkali fiber products with the same content of methyl cellulose, the power consumption of the diaphragm type filter press is much lower than that of the mesh hole press roller type press machine.

[0090] Example 4

[0091] ​Using slurry raw material with a concentration of 8%, different alkali fibers with different content of methyl fiber were obtained by adjusting the pressing pressure, and the power consumption of the two pressing methods was compared. The specific experimental data is shown in Table 4.

[0092] Table 4 Pressing power of different alkali fibers with different content of methyl fiber obtained by two pressing methods when the slurry concentration is 8%

[0093] MFC content 30.0％ 31.0％ 32.0％ 33.0％ 34.0％ 35.0％ 36.0％ 37.0％ 38.0％ 39.0％ 40.0％ Mesh press power consumption (kWh / ton of alkali fiber) 11.77 12.35 13.02 14.63 15.40 16.88 18.13 20.64 / / / Diaphragm filter press power consumption (kWh / ton of alkali fiber) 5.37 6.38 7.56 8.42 9.63 10.64 11.79 12.96 14.32 15.97 17.84 Mesh press pressure (bar) 0.51 0.53 0.56 0.60 0.66 0.75 0.84 0.94 Overpressure Overpressure Overpressure Diaphragm filter press pressure (bar) 0.73 0.79 0.87 0.96 1.06 1.17 1.30 1.45 1.63 1.85 2.08

[0094] As can be seen from Table 4, when the content of methyl fiber is greater than 37%, the pressure of the mesh screen roller press has approached the upper limit, and it is impossible to obtain alkali fiber products with a content of methyl fiber of 37% or more by increasing the pressing pressure, while the alkali fiber products with a higher content of methyl fiber can be obtained by the present application. Moreover, within the range of the content of methyl fiber in the present embodiment, the power consumption of the diaphragm filter press is much lower than that of the mesh screen roller press under the condition of obtaining alkali fiber products with the same content of methyl fiber.

[0095] Figure 5 The power consumption comparison chart of the mesh screen roller press and the diaphragm filter press under different discharge methyl fiber content conditions in Example 3 and Example 4. Among them, the mesh screen roller press in the chart is the traditional mesh screen roller press, and the plate block press is the diaphragm filter press in the present application. From Figure 5 It can be seen from the chart that under different discharge methyl fiber content conditions, the power consumption of the diaphragm filter press is much lower than that of the mesh screen roller press.

[0096] The power consumption of the diaphragm filter press is lower than that of the mesh screen roller press because the latter needs to continuously consume electric energy to overcome the frictional resistance of the alkali fiber passing between the two rotating press rollers while the slurry pump is continuously feeding, while the former only needs to provide static pressure during pressing after the slurry pump feeds, and does not produce the above power consumption.

[0097] From the comparison of the above four groups of examples, it can be seen that the power consumption of the diaphragm filter press is much lower than that of the mesh screen roller press, the allowable concentration range of the slurry raw material used is wider, and the content of methyl fiber in the alkali fiber product is higher. Therefore, the pressing efficiency of the present application is higher, and the pressing effect is better.

[0098] Although the present application discloses the preferred embodiments to achieve the above-mentioned purposes, it is not intended to limit the structural features of the present application. Any person skilled in the art should know that any easy-to-think change or modification is possible under the technical spirit of the present application, and all are covered by the patent application range of the present application.

Claims

1. A pulp impregnation press system, characterized by The device comprises an impregnation liquid metering tank (1), an impregnation barrel (2) and a diaphragm filter press (3) connected in sequence, a water tank (4) is also connected to the water inlet of the diaphragm filter press (3), a high-pressure water pump (5) is arranged on the water inlet pipeline (9) of the diaphragm filter press (3), a pressure liquid tank (6) is connected to the liquid outlet end of the diaphragm filter press (3), and the outlet end of the pressure liquid tank (6) is connected to the impregnation liquid metering tank (1).

2. The pulp impregnation press system of claim 1, wherein, An air compressor (11) is further arranged, the diaphragm filter press (3) is provided with a first air inlet (301), a second air inlet (302), a first air outlet (303) and a second air outlet (304), the air compressor (11) is connected to the first air inlet (301) and the second air inlet (302) through a first air pipeline (305) and a second air pipeline (306) respectively, the first air outlet (303) is connected to the impregnation barrel (2) through a third air pipeline (307), the second air outlet (304) is connected to the pressure liquid tank (6) through a fourth air pipeline (308), and control valves are arranged on the connecting pipelines of the first air pipeline (305), the second air pipeline (306), the third air pipeline (307), the second air pipeline (306) and the fourth air pipeline (308).

3. The pulp impregnation press system of claim 1, wherein, The impregnation barrel (2) and the diaphragm filter press (3) are connected through a first liquid pipeline (8), and a slurry pump (801) is arranged on the first liquid pipeline (8).

4. The pulp impregnation press system of claim 3, wherein, An electric contact pressure gauge (802) is further arranged on the first liquid pipeline (8), and the electric contact pressure gauge (802) is electrically connected to the slurry pump (801).

5. The pulp impregnation press system of claim 1, wherein, The pressure liquid tank (6) and the impregnation liquid metering tank (1) are connected through a second liquid pipeline (7), a pressure liquid pump (701) and an accumulated flow meter (702) are arranged on the second liquid pipeline (7), and the pressure liquid pump (701) is electrically connected to the accumulated flow meter (702).

6. The pulp impregnation press system of claim 1, wherein, A first liquid inlet (101) for adding dilute lye and a second liquid inlet (102) for adding concentrated lye are arranged on the impregnation liquid metering tank (1) respectively, a first motor (104) is fixedly arranged on the top of the impregnation liquid metering tank (1), a first stirring paddle (105) is fixedly arranged on the output end of the first motor (104), and the first stirring paddle (105) penetrates through the top of the impregnation liquid metering tank (1) and extends into the interior thereof.

7. The pulp impregnation press system of claim 1, wherein, A heating circulation machine (107) is further arranged on the outside of the impregnation liquid metering tank (1).

8. The pulp impregnation press system of claim 1, wherein, A first feeding port (201) for adding pulp is arranged on the impregnation barrel (2), a second motor (202) is fixedly arranged on the top of the impregnation barrel (2), a second stirring paddle (203) is fixedly connected to the output end of the second motor (202), and the second stirring paddle (203) penetrates through the top of the impregnation barrel (2) and extends into the interior thereof.

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