CN115746948B

CN115746948B - Palm kernel direct leaching system and leaching process

Info

Publication number: CN115746948B
Application number: CN202211280190.8A
Authority: CN
Inventors: 徐斌; 荣臻; 尹越峰; 梁椿松
Original assignee: Myande Group Co Ltd
Current assignee: Myande Group Co Ltd
Priority date: 2022-10-19
Filing date: 2022-10-19
Publication date: 2024-02-06
Anticipated expiration: 2042-10-19
Also published as: CN115746948A

Abstract

The invention discloses a palm kernel direct leaching system and a leaching process.A palm kernel temporary storage bin outlet is connected with an inlet of a crusher, an outlet of the crusher is connected with an inlet of a embryo rolling machine, an outlet of the embryo rolling machine is connected with an inlet of a quantitative auger through a conveying mechanism, an outlet of the quantitative auger is connected with a temporary storage hopper inlet of a cascade tunnel type leacher, a thick mixing outlet of the leacher is connected with an inlet of a cyclone separation device through a thick mixing pump I, a top outlet of the cyclone separation device is connected with an inlet of a thick mixing tank, a lower outlet of the thick mixing tank is connected with a thick extract inlet of an extract evaporation recovery system through a thick mixing tank pump II, and a recycling solvent outlet of the extract evaporation recovery system is connected with a new dissolution spray pipe of the leacher through a fresh solvent pump. The solid materials are fished out from the last-stage soaking tank and then sequentially fall into the previous-stage soaking tank for gradual extraction, the liquid level is lowered from the first stage to the rear in a gradient manner, the low-concentration extraction liquid penetrates through the filtering grid plate and the wet meal and flows into the next-stage soaking tank, and the extraction efficiency is high.

Description

Palm kernel direct leaching system and leaching process

Technical Field

The invention relates to an extraction process, in particular to a palm kernel direct leaching system, and also relates to a palm kernel direct leaching process, belonging to the technical field of kernel extraction.

Background

Oil palm is the most efficient oil-producing plant in the world. In malaysia, at present, at most about 5 tons of grease can be produced per hectare of oil palm, and the grease produced per hectare of oil palm is 5 times higher than that of peanuts with the same area and 9 times higher than that of soybeans. The average yield per hectare of mature oil palm plantation was 4.5 tons of crude palm oil per year. The palm oil, the residual fiber residue and the kernel can be obtained after the oil palm fruit cluster is squeezed. The kernel and shell can be separated after the kernel is peeled off. The palm kernel is milky white globular, has a particle size of 8-10mm, and contains about 50% of oil.

The traditional oil preparation process of the palm kernels is generally as follows: crushing, rolling, steaming and frying and squeezing. Wherein, because the palm kernel has high oil content, the hearth pressure can not be too high when the squeezer squeezes, two times of squeezing are needed, and the first time of squeezing only squeezes the palm kernel embryo sheet with about 50% of oil into a pre-squeezed cake with 16-18% of oil by the squeezer, and the pre-squeezed cake is finally squeezed by the squeezer with higher hearth pressure to separate out residual oil, thus obtaining the squeezed palm kernel cake with 5-8% of oil. The mechanical energy consumed in the pressing process is high, so that the electricity consumption is high, and the equipment wear is high. The processing capacity of a single press is only 50TPD, and for a common palm kernel pressing factory with 1000TPD, at least more than 40 presses are required to continuously operate for 24 hours together to finish the pre-pressing and the secondary pressing, and a plurality of other presses are also required. The inspection is continuously carried out in workshops with diffuse dust and steam fumigation winding, and a certain oil press with reduced performance is disassembled from time to time, and spare parts such as a pressing cage, a pressing screw and the like are replaced. Thus, palm kernel press plants must be equipped with service, maintenance teams and maintain a large pool of spare parts. The resulting palm kernel cake generally has 7-8% residual oil (minimum 5% by deep pressing, but poor economy). This is a great difference from the leaching process where the residue is generally controlled below 1.0%. Considering the physical characteristics of the palm kernel, the residual oil is difficult to reduce to the conventional level.

If the residual oil of the leached meal is controlled within 1.5 percent, the yield of grease can be increased by 55 to 65kg per ton of palm kernel, and the average gain is increased by 600 yuan per ton of raw material according to 10 yuan/kg. The high value oil return of a conventional palm kernel oil plant of 1000TPD is increased by 60 ten thousand yuan/day. Of course, the yield of low-value palm kernel meal is reduced by about 6%, the selling price of the palm kernel meal is about 1000 yuan per ton, and the weight loss of the meal is about 60 yuan per ton. According to the simple calculation, the leaching oil extraction is adopted, the income is increased by 540 yuan per ton, and the direct income can be increased by 54 ten thousand yuan per day for a 1000TPD factory. The comprehensive benefit is slightly higher than 60 ten thousand yuan, which is a great improvement. Meanwhile, the leaching technology has little equipment abrasion, low operation cost, high automation degree and large capacity scale, and can further reduce the production cost. This is a tremendous advancement.

The traditional process has low production efficiency, high labor intensity and severe working environment, oil extraction is incomplete and high consumption is achieved, and breakthrough needs to be made in the processing technology and equipment. The key to realizing good economy and production efficiency of extracting oil from palm kernel is the breakthrough in the processing technology, and the development of a palm kernel leacher is the key.

The existing common annular leacher, box chain leacher and horizontal rotation leacher have good adaptability to common bulk materials such as common oil embryo sheets, puffing materials and mechanically pressed cakes, and the production scale can be extremely large, and the consumption index can be extremely low. The various leachers mainly utilize the better permeability of the material bed and the flow channel formed by the gaps among the material particles, and realize the main mass transfer process by using a solvent circulating leaching mode. A unit volume of oil material bed is generally provided with 10% -30% of gaps according to the granularity and the particle structure, and mixed oil or fresh solvent flows in a flow channel to repeatedly wash and soak oil particles so as to realize mass transfer. During leaching, the circulating amount of the extraction liquid is about 10 times of the mass ratio of the solid materials, so that the leaching and soaking are sufficient. When the oil blank sheet is formed poorly and the powder degree is too high, the phenomenon that the permeability of the material bed is poor or the material bed is completely impermeable can occur, so that the residual oil in the leached meal is high. The causes are as follows: more powder plugs the permeate channels, resulting in fewer permeate channels or complete plugging, reducing or terminating the mass transfer process efficiency.

If the permeability of the conventional oil is poor, the impermeability can be basically eliminated by adjusting the indexes such as the temperature, the moisture, the granularity, the thickness and the like of the oil in the pretreatment stage and adjusting the granularity and the moisture content of the immersed cake blank to meet the immersing conditions. The key points are as follows: the wall breaking of the oil cells is realized as much as possible, the oil cells are rolled into a sheet shape, meanwhile, the powder degree of the immersed material is controlled, the powder is prevented from fully or locally blocking the permeable flow passage, and the material bed formed by stacking the materials is ensured to have an intact permeable flow passage, so that the continuous leaching process is realized.

The components of the palm kernel: 50% of fat, 24% of protein, 10% of moisture, 9% of lignin, 5% of cellulose and 2% of ash. Because of the low cellulose content, the green sheet after rolling is not formed and has extremely high powder degree. Since the pressing process is insensitive to the powder content of the material, but is a fatal big nuisance to conventional leaching.

In conclusion, the extraction of palm kernel oil by adopting a leaching method tends to be great, but a key core device palm kernel leacher cannot be broken through in engineering design, and the development and the income of the market segment are severely restricted.

The Chinese patent with publication number CN 104474735B discloses a continuous extraction device and process. The device comprises an extraction tank with a closed main body, wherein N groups of chain scraper devices are obliquely arranged in the extraction tank, each group of chain scraper devices respectively comprises an upper shaft and a lower shaft, the upper shafts and the lower shafts which are in the same group and at the same end are in transmission connection through a single circle of chain, and scrapers are uniformly fixed on the chains; each group of chain scraper devices are mutually independent and respectively rotate in a closed loop. An extraction material inlet and a solvent inlet are arranged at different positions on the upper part of the extraction tank, and an extraction liquid outlet and an extraction material outlet are respectively arranged at two ends of the extraction tank.

The extraction device has the following problems: 1. most of the solid materials are in laminar flow contact with the extraction liquid, so that the solid materials and the extraction liquid are insufficiently mixed;

2. the extract automatically flows through the fall, the light phase is positioned at the upper part of the liquid layer, and short circuit is easily generated in new solution;

3. the solid material has no obvious draining process, more concentrated extraction liquid is mixed in the climbing material pushed by the scraper, so that the concentration of the solvent at the low concentration side is increased, the extraction power is reduced, and the extraction efficiency is reduced;

4. the extraction path is seemingly longer, but the utilization rate of the upper layer screen surface of each group of leaching units is very low;

5. a plurality of speed reducers are required to drive, and at least a feeding speed reducer, a main driving speed reducer and a discharging speed reducer are usually arranged, wherein the main driving speed reducer provides power for a plurality of groups of chain scraper devices in the middle;

6. the output rotation speeds of the three speed reducers are different, so that in order to prevent blockage caused by too much feeding or too slow discharging, the rotation speed of the speed reducer at the discharging end is higher, the rotation speed of the speed reducer at the feeding end is lower, and the rotation speed of the main driving speed reducer is positioned between the feeding and the discharging, and the speed regulation control is needed respectively;

7. each extraction unit is provided with a group of single-circle chains, namely, each circle of chain belt has a group of driving shafts and guide shafts which rotate respectively, the dynamic seals are more, the bearing seats are all external, and the sealing difficulty and the leakage risk are increased; the extraction solvent is typically hexane, methanol (or ethanol), diethyl ether, acetone, and other inflammable, explosive or even toxic organic matters, and leakage leads to explosion risk and increases the running cost.

Disclosure of Invention

The primary aim of the invention is to overcome the problems in the prior art and provide a palm kernel direct leaching system, which adopts a cascade tunnel type leacher to extract palm kernel embryo pieces, solid materials and extract liquid can realize full countercurrent long flow contact, strengthen mass transfer process, and the solvent cannot be short-circuited, so that the extraction efficiency is high.

In order to solve the technical problems, the palm kernel direct leaching system comprises a palm kernel temporary storage bin, wherein an outlet of the palm kernel temporary storage bin is connected with an inlet of a crusher, an outlet of the crusher is connected with an inlet of a embryo rolling machine, an outlet of the embryo rolling machine is connected with an inlet of a quantitative auger through a conveying mechanism, an outlet of the quantitative auger is connected with a temporary storage bucket inlet of a cascade tunnel type leacher, a thick mixing outlet of the cascade tunnel type leacher is connected with an inlet of a cyclone separation device through a thick mixing extraction pump I, a top outlet of the cyclone separation device is connected with an inlet of a thick mixing tank, a lower outlet of the thick mixing tank is connected with a thick extract inlet of an extract evaporation recovery system through a thick mixing tank extraction pump II, and a recycling solvent outlet of the extract evaporation recovery system is connected with a new dissolution spray pipe of the cascade tunnel type leacher through a fresh solvent pump.

As an improvement of the invention, a wet dreg outlet of the cascade tunnel type leacher is connected with a lower end inlet of a wet dreg bent scraper, an upper end outlet of the wet dreg bent scraper is connected with a feeding port of a vertical type steam-off machine, a discharging port of the vertical type steam-off machine is connected with a lower end inlet of a dry dreg scraper, an upper end outlet of the dry dreg scraper is connected with an inlet of a classifying screen, a palm kernel finished dreg outlet is arranged under the classifying screen, and a screen upper outlet of the classifying screen is connected with an inlet of the crusher.

As a further improvement of the invention, the rear end of the box body of the cascade tunnel type leacher is a feeding end, and the wet meal outlet is positioned at the front end of the box body; the box body inner cavity is provided with a plurality of levels of soaking units from front to back in sequence, each level of soaking units respectively comprises a soaking tank, a lower shaft and an upper shaft, each lower shaft is respectively positioned at the bottom of the same level of soaking tank, each level of upper shaft is respectively positioned above the previous level of soaking tank, the first level of upper shaft is positioned above a wet meal outlet, a conveying chain is S-shaped and sequentially and alternately bypasses conveying chain wheels of each level of lower shaft and upper shaft, the conveying chain wheel of the first level of upper shaft bypasses the conveying chain wheel of the first level of upper shaft and then bypasses the conveying chain wheel of the last level of lower shaft again through a guide sliding rail at the feeding side to form a closed loop, and scraping plates are uniformly arranged along the circumference of the conveying chain.

As a further improvement of the invention, a first-stage soaking tank is close to the wet meal outlet, a concentrated mixed reflux port is arranged above a final-stage soaking tank, and the cyclone separation device and the bottom outlet of the concentrated mixed tank are connected with the concentrated mixed reflux port; each stage of soaking tank respectively comprises a wallboard, an arc bottom and an inclined bottom plate which are connected into a whole in sequence, the lower shaft of the stage is immersed in the arc bottom of the soaking tank of the stage, the upper end of the inclined bottom plate extends towards the rear side of the upper shaft of the stage, and the upper end of the wallboard is connected below the inclined bottom plate of the soaking tank of the subsequent stage.

As a further improvement of the invention, the upper parts of the inclined bottom plates of each stage except the first stage are respectively provided with a filtering grid plate, and the lower edge heights of the filtering grid plates are gradually reduced from front to back and are higher than the tops of the wallboards; the soaking units of each level are also respectively provided with baffle plates, each baffle plate is a solid plate parallel to the inclined bottom plates of each level, the upper ends of the baffle plates are higher than the liquid level, and the lower ends of the baffle plates are inserted into the lower part of the soaking tank; the baffle plates of each stage and the lower end face of the inclined bottom plate of the subsequent stage form a downlink tunnel of materials, and the baffle plates of each stage and the upper end face of the inclined bottom plate of the previous stage form an uplink tunnel of materials; the scraping plate descends along the baffle plate and ascends along the inclined bottom plate.

As a further improvement of the invention, the baffle plate of the present stage extends from the front side of the upper shaft of the subsequent stage to the top of the lower shaft of the present stage; the plane of the lower shaft axis of the present stage and the plane of the upper shaft axis of the present stage are intersected with the inclined bottom plate of the present stage and the baffle plate at an acute angle; the upper end of the inclined bottom plate is higher than the horizontal plane where the axis of the upper shaft is located, and the upper end of the baffle plate is close to the horizontal plane where the axis of the upper shaft is located.

As a further improvement of the invention, the new solution spray pipe is sprayed at the middle section of the inclined bottom plate of the first-stage soaking tank; the liquid level of the former stage soaking tank is higher than that of the latter stage soaking tank, the thick mixing outlet is positioned on the rear wall of the last stage soaking tank, a baffle plate penetrating into the liquid level is arranged at the front side of the thick mixing outlet, and a thick mixing sedimentation zone is formed between the baffle plate and the rear wall of the last stage soaking tank.

As a further improvement of the invention, the bottom of the temporary storage hopper is in butt joint with a solid material inlet at the rear part of the top wall of the box body, and the solid material inlet is positioned above the final baffle plate; the front of the solid material feed inlet is provided with a semi-fluid material feed inlet, the lower part of the semi-fluid material feed inlet is provided with a feed platform, and the feed platform is positioned above the last-stage upper shaft.

As a further improvement of the invention, a certain upper shaft is used as a main driving shaft, and the main driving shaft is driven by a speed reducer; the rest part or all of the upper shafts are used as auxiliary driving shafts, and the auxiliary driving shafts are synchronously driven by the main driving shafts; the auxiliary driving chain wheel is arranged at the shaft end of the auxiliary driving shaft through the expansion sleeve.

The invention also aims to overcome the problems in the prior art and provide a palm kernel direct leaching process, wherein a cascade tunnel type leacher is adopted to extract palm kernel embryo pieces, solid materials and extract liquid can realize full countercurrent long-flow contact, the mass transfer process is strengthened, the solvent cannot be short-circuited, and the extraction efficiency is high.

In order to solve the technical problems, the invention relates to a palm kernel direct leaching process, which adopts the cascade tunnel type leacher according to any one of claims 1 to 9, wherein the palm kernel is firstly crushed into 8-10 pieces by a crusher, then rolled into embryo pieces with the thickness of 0.25-0.35MM, then falls into a final soaking tank of the cascade tunnel type leacher, is mixed with extract with the solute concentration of 30-40%, is fished out from the final soaking tank, then falls into a previous soaking tank for gradual extraction, finally falls into a first soaking tank, is mixed with fresh extract with the solute concentration of 0.5-1%, is drained, is screened after evaporation of solvent, and is crushed by returning particles on a screen with the thickness of more than 2MM into the crusher, and is drained as a finished product with the concentration of less than 2 MM; and (3) carrying out solid-liquid separation on the concentrated mixture discharged from the final-stage soaking tank, returning the solid phase to the final-stage soaking tank, enabling the liquid phase to enter an extraction liquid evaporation recovery system for evaporation to obtain palm kernel crude oil and fresh solvent, and returning the fresh solvent to the first-stage soaking tank for cyclic extraction.

Preferably, in the extraction process, a conveying chain drives a scraper to descend along a tunnel above a certain level of baffle plate, palm kernel embryo sheets or wet meal are pushed downwards to be immersed into a current level immersion tank, the scraper bypasses a lower shaft of the current level and ascends along the tunnel below the baffle plate, the wet meal is fished out, ascends along an inclined bottom plate of the current level immersion tank and is drained, and then the wet meal falls to the upper part of a next level of baffle plate from the upper end of the inclined bottom plate or after turning over the upper shaft of the current level; the liquid level descends from the first stage soaking tank to the back echelon, under the action of the inter-stage liquid level difference, the high-level extract liquid at the low concentration side penetrates through the filter grid plate on the inclined bottom plate and the wet pulp on the filter grid plate, flows into the later stage soaking tank, realizes the preliminary washing of the wet pulp and the replacement of the concentrated extract liquid in the wet pulp, and then the wet pulp goes into the draining section.

Compared with the prior art, the invention has the following beneficial effects: 1. the solvent and the wet meal are always guaranteed to be soaked and contacted in countercurrent in a tunnel formed by the inclined bottom plate and the baffle plate, the forced mass transfer process is carried out, and high extraction power is always kept;

2. after the new solution enters the first-stage soaking tank, the new solution automatically overflows backward step by utilizing the liquid level difference, flows in a zigzag way through the baffle plates, has long effective working path, fully contacts with materials for mass transfer in each extraction unit, and does not generate a short circuit phenomenon along the surface flow;

3. the material undergoes the steps of immersing, solid-liquid mixing, fishing out, washing, draining and the like in each extraction unit, and the solid material finally enters a first-stage soaking tank, is fully mixed with fresh solvent, is fished out by a scraper and drained out of the machine;

4. the solid material after each level of extraction has an obvious draining section on the inclined bottom plate, and concentrated extract liquid in the solid material is fully drained before the solid material enters the next level of soaking, so that concentration gradient is easy to form in each level of soaking tanks, and the extract liquid has larger extraction power; the baffling channel is added to each level of extraction liquid, the flow of the liquid is more orderly and reasonable, the extraction principle is fully matched, the extraction efficiency can be improved by more than 20%, and the dominant extraction process aiming at powdery or semi-fluid solid materials can be formed;

5. The conveying chains of the extraction units which are mutually independent are integrated into a group of built-in conveying chains, solid materials move along with the conveying chains through multi-axis guiding turning, reliable transmission can be realized by using a single speed reducer for the whole machine, the structure is simple, the blocking risk is small, the control is convenient, and the fault points are few; meanwhile, the manufacturing cost and the maintenance cost are reduced, and the reliability of the equipment is improved;

6. even if the external transmission chain has abnormal working conditions, the internal transmission chain can still reliably run, thereby avoiding causing fault emergency stop and improving the reliability and safety of the equipment;

7. aiming at the dangerous environment of the inflammable and explosive organic solvent in the extraction equipment, the sealing difficulty and leakage risk are reduced, and the production environment is improved;

8. a large number of mixed oil circulating pumps, complicated pipelines and control systems are omitted, the use is simple and convenient, and the operation cost is low. The equipment has simple internal structure, high strength, strong adaptability to materials, simple and convenient operation and use and low maintenance requirement, and is suitable for being used in underdeveloped areas or crude environments;

9. the leacher meets the skid-mounted use requirement, has compact external dimension, strictly controls the length, width and height of equipment, can be transported by common vehicles, has convenient road transportation and strong maneuverability, and meets the requirement of mobile operations such as petroleum drilling waste and the like.

Drawings

The invention will now be described in further detail with reference to the drawings and the detailed description, which are provided for reference and illustration only and are not intended to limit the invention.

FIG. 1 is a flow chart of the palm kernel direct leaching system of the present invention;

FIG. 2 is a front view of a cascade tunnel type extractor of the present invention;

FIG. 3 is a top view of FIG. 2;

FIG. 4 is a cross-sectional view of the palm kernel direct leaching system of the present invention;

FIG. 5 is a perspective view of the palm kernel direct leaching system of the present invention;

FIG. 6 is an enlarged perspective view of a soaking tank according to the present invention;

FIG. 7 is a perspective view of a drive mechanism according to the present invention;

FIG. 8 is a cross-sectional view of an auxiliary drive sprocket of the present invention;

FIG. 9 is a perspective view of a stall warning mechanism of the present invention;

FIG. 10 is a front view of the lower shaft of the present invention;

FIG. 11 is a left side view of FIG. 10;

FIG. 12 is a perspective view of the lower shaft of the present invention;

FIG. 13 is a cross-sectional view of FIG. 12;

FIG. 14 is a front view of the feed adjustment gate of the present invention;

FIG. 15 is a top view of FIG. 14;

FIG. 16 is an enlarged view of the driver end of FIG. 15;

FIG. 17 is a perspective view of FIG. 14;

in the figure: E1. temporary storage bin of palm kernel; E2. a crusher; E3. a blank rolling machine; E4. a first horizontal scraper; E5. a hoist; E6. a horizontal scraping plate II; E7. a workshop bin; E8. quantitative auger; E9. a cascade tunnel leacher; E10. a first pump for pumping out the concentrated mixture; E11. a cyclone separation device; E12. a dense mixing tank; E13. pumping out the second pump from the thick mixing tank; E14. an extract evaporation recovery system; e14a. concentrated extract inlet; e14b recycled solvent outlet; e14c. palm kernel crude oil outlet; E15. a fresh solvent pump; E16. a wet dreg bending scraper; E17. vertical steam-off machine; E18. a dry dreg scraper; E19. classifying screen; e19a. exit of palm kernel meal; E20. a tail gas condenser;

1. A case; 1a, a solid material inlet; 1b, a semi-fluid material feed inlet; 1c, a feeding platform; 1d, a wet dreg outlet; 1e, an overflow port of the box body; 1f, a free gas interface; 1g, an access door; 1h, horizontal support rail; 1j, a feeding side guiding sliding rail; 1k, guiding a sliding rail on the discharging side; 1m, a temporary storage hopper; 1n, a thick mixed reflux port;

2. a feed regulating gate; 2a, a hand wheel; 2b, a worm and gear driver; 2b1, a stop arm; 2c, a transmission shaft; 2c1, locking the nut; 2d, a transmission shaft bearing seat; 2d1, supporting lugs of a bearing seat of the transmission shaft; 2d2, capping; 2d3, bearing bushes; 2d4, a transmission shaft sealing ring; 2e, a transmission sleeve; 2f, actively swinging the plate; 2g, arc flashboard; 2h, rib plates; 2h1, evacuating the notch; 2j, a driven swing plate; 2k, a driven shaft; 2m, a driven end bearing seat; 2n, gate flange sealing plates; 2n1, a sealing plate positioning boss; 2p, a gate sealing plate sealing gasket;

3. a soaking tank; 3a, wallboard; 3b, arc bottom; 3c, an inclined bottom plate; 3d, filtering grid plates; 3e, a dense mixing outlet; 4. a baffle plate; 5. a striker plate; 6. a dense mixing sedimentation zone;

7. a lower shaft; 7a, a lower shaft conveying chain wheel; 7b, a left-handed bushing; 7b1, left-handed threads; 7c, a right-handed bushing; 7c1, right-handed threads; 7d, sliding bearings; 7d1. A plain bearing outer flange; 7e, a lower shaft bearing seat; 7e1, an outer flange of a lower shaft bearing seat; 7e2, a lower shaft bearing seat screw; 7f, sealing the lower shaft flange; 7g, a blank cap; 7g1, a cover inner convex ring; 7g2, a cover screw; 7g3, a blank cap sealing gasket; 7h, a lower shaft bearing seat sealing gasket; 7j, a lower shaft flange gasket;

8. An upper shaft; 8a, an upper shaft conveying chain wheel; 8-1, a main driving shaft; 8-1a, a large chain wheel; 8-1b, a main driving chain wheel; 8-2, an auxiliary driving shaft; 8-2a, sensing piece; 8-2b, a proximity switch; 8-3, a discharging shaft;

9. an auxiliary driving chain wheel; 9a, expanding the sleeve on the inner conical surface; 9b, an outer conical surface expansion sleeve; 9c, expanding the screw; 10. a speed reducer; 11. a speed reducer transmission chain; 12. an auxiliary transmission chain; 13. a conveyor chain; 13a, scraping plate; 14. an evacuation tube; 15. a new solution spray pipe.

Detailed Description

In the following description of the present invention, the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are merely for convenience in describing the present invention and simplifying the description, and do not mean that the device must have a specific orientation. Herein, "back" near the solids feed inlet and "front" near the wet meal outlet.

The invention is further described with reference to the following detailed drawings in order to make the technical means, the creation characteristics, the achievement of the purpose and the effect of the implementation of the invention easy to understand.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

As shown in fig. 1, the palm kernel direct leaching system comprises a palm kernel temporary storage bin E1, wherein an outlet of the palm kernel temporary storage bin E1 is connected with an inlet of a crusher E2, an outlet of the crusher E2 is connected with an inlet of a blank rolling machine E3, an outlet of the blank rolling machine E3 is connected with an inlet of a horizontal scraper E4, an outlet of the horizontal scraper E4 is connected with an inlet of a lower end of a lifting machine E5, an outlet of an upper end of the lifting machine E5 is connected with an inlet of a horizontal scraper E6, an outlet of the horizontal scraper E6 is connected with an inlet of a workshop bin E7, a bottom outlet of the workshop bin E7 is connected with an inlet of a quantitative auger E8, an outlet of the quantitative auger E8 is connected with an inlet of a temporary storage hopper 1m of a step tunnel type extractor E9, a rich mixed outlet of the step tunnel type extractor E9 is connected with an inlet of a cyclone separation device E11 through a rich pump E10, a top outlet of the cyclone separation device E11 is connected with an inlet of a mixing tank E12, a top exhaust of the mixing tank E12 is connected with a condenser E20, a bottom outlet of the mixing tank E12 is connected with a new solvent extraction system E14a of a spray pump E14b of a new solvent extraction system of a leaching system E14, and a new solvent extraction system E14b is recovered through a spray pump 14b of a new solvent extraction system E14.

The wet pulp outlet of the cascade tunnel type leacher E9 is connected with the inlet at the lower end of a wet pulp bent scraper E16, the outlet at the upper end of the wet pulp bent scraper E16 is connected with the inlet of a vertical evaporator-separator E17, the outlet of the vertical evaporator-separator E17 is connected with the inlet at the lower end of a dry pulp scraper E18, the outlet at the upper end of the dry pulp scraper E18 is connected with the inlet of a classifying screen E19, a palm kernel finished product pulp outlet E19a is arranged below the classifying screen E19, and the outlet on the classifying screen E19 is connected with the inlet of a crusher E2.

Discharging palm kernels with the water content lower than 10% from the palm kernel temporary storage bin E1, and then crushing the palm kernels into 8-10 pieces by a crusher E2, wherein the particle size is 2.5-5mm; then the mixture enters a embryo rolling machine E3 to roll into palm kernel embryo sheets with the thickness of 0.25-0.35mm, the palm kernel embryo sheets are sent into the inlet of the lower end of a lifting machine E5 by a first horizontal scraping plate E4, the lifting machine E5 lifts the palm kernel embryo sheets to a high position, and then the palm kernel embryo sheets are sent into a workshop bin E7 by a second horizontal scraping plate E6 for temporary storage. After being discharged from a workshop bin E7, the materials are sent into a temporary storage hopper 1m by a quantitative auger E8 and then enter a final-stage soaking tank of a step tunnel type leacher E9 to be mixed with extract with the solute concentration of 30-40%, the materials are fished out from the final-stage soaking tank and then sequentially fall into a previous-stage soaking tank to be extracted step by step, finally fall into the first-stage soaking tank to be mixed with fresh extract with the solute concentration of 0.5-1%, wet meal is discharged after draining, and the dry-basis oil content is within 2.5%.

The wet meal after extraction and draining is sent out by a wet meal bent scraper E16 and lifted to a high position, then enters a vertical evaporator E17 to evaporate solvent, and mixed steam of the evaporated solvent and water enters an extract evaporation recovery system E14 to recover heat and the solvent, and the water is removed.

The dried meal discharged from the bottom of the vertical type steam-stripping machine E17 is sent into a classifying screen E19 by a dried meal scraper E18, the finished product meal with the undersize of less than 2mm is sieved and separated by wind power through a 25-mesh sieve, the finished product meal with the undersize of less than 2mm is discharged from a palm kernel finished product meal outlet E19a, the over-2 mm on-screen particles are returned into a crusher E2 to be crushed, and the repeated crushing content accounts for about 5 percent of the total amount of the finished product meal.

The concentrated mixture discharged from the final soaking tank is pumped out by a concentrated mixture pumping pump E10, is sent into a cyclone separation device E11 for centrifugal separation, solid-liquid separation is realized through two-stage cyclone, the solid phase enters a concentrated mixture reflux port 1n and returns to the final soaking tank, the liquid phase enters a concentrated mixture tank E12 for temporary storage, and sediment is discharged from the bottom of the concentrated mixture tank E12 at regular intervals and also enters the concentrated mixture reflux port 1 n. And pumping the concentrated extract discharged from a liquid outlet at the lower part of the concentrated mixing tank out of the second pump E13 of the concentrated mixing tank, feeding the concentrated extract into a concentrated extract inlet E14a of an extract evaporation recovery system E14, evaporating to obtain palm kernel crude oil and fresh solvent, and discharging the palm kernel crude oil from a palm kernel crude oil outlet E14 c. Fresh solvent is discharged from a recycled solvent outlet E14b, is pumped back to a fresh solvent spray pipe by a fresh solvent pump E15 through a metering pump for spraying, and is returned to the first-stage soaking tank for circulating extraction.

As shown in fig. 2 to 7, the cascade tunnel type leacher E9 comprises a box body 1, wherein the rear end of the box body 1 is a feeding end, the front end of the box body 1 is provided with a wet dreg outlet 1d with a downward opening, the interior of the box body 1 is a solvent environment, and all the positions of connecting surfaces, flanges and the like meet the airtight requirement. The outer shell is provided with an integral flange joint surface, so that the rigidity of the shell is enhanced, the manufacturing precision is improved, and the sealing and airtight functions are improved. The inner cavity of the box body is provided with a plurality of stages of soaking units from front to back, the first stage of soaking unit is close to the wet dreg outlet 1d, and the last stage of soaking unit is positioned at the rear end of the box body.

Each stage of soaking unit respectively comprises a soaking tank 3, a baffle plate 4, a lower shaft 7 and an upper shaft 8, wherein the soaking tank 3 comprises a wallboard 3a, an arc-shaped bottom 3b and an inclined bottom plate 3c which are sequentially connected into a whole, the arc-shaped bottom 3b accommodates the lower shaft 7 of the stage, the upper shaft 8 of the stage is respectively positioned above the soaking tank of the previous stage, and the upper shaft of the first stage is positioned above the wet meal outlet 1 d. The upper end of the inclined bottom plate 3c extends to the rear side of the upper shaft 8 of the current stage, and the upper end of the wall plate 3a is connected below the inclined bottom plate 3c of the soaking tank of the subsequent stage.

The two ends of each stage of lower shaft 7 positioned in the soaking tank are respectively provided with a lower shaft conveying chain wheel 7a, and the arc-shaped bottom 3b is matched with the bottom shape of the lower shaft conveying chain wheel 7a, so that the lower shaft conveying chain wheel 7a can freely rotate in the arc-shaped bottom 3b of the soaking tank.

The two ends of each stage of upper shaft 8 in the box body 1 are respectively provided with an upper shaft conveying chain wheel 8a, the same conveying chain 13 sequentially and alternately bypasses each stage of lower shaft conveying chain wheels 7a and the upper shaft conveying chain wheels 8a in an S shape, after bypassing the first stage of upper shaft conveying chain wheels 8a, the upper shaft passes through a horizontal empty load section and bypasses the last stage of lower shaft conveying chain wheels 7a again through a feeding side guide sliding rail 1j to form a closed loop, and scraping plates are uniformly arranged along the circumference of the conveying chain 13.

The feeding side guide slide rail 1j is positioned at the front side of the solid material feed port 1a and above the rear side of the last stage upper shaft. The final lower shaft is located at the rear side of the solid material feed opening 1a and below the conveying chain 13.

A horizontal supporting rail 1h is arranged between the feeding side guiding sliding rail 1j and the discharging shaft and is supported below the conveying chain 13 of the horizontal no-load section.

Because the first-stage upper shaft is higher as the discharging shaft 8-3, the discharging side guide slide rail 1k is arranged below the rear side of the discharging shaft 8-3 and is supported below the conveying chain 13.

The inclined bottom plate 3c is parallel to a tangent line between the front side of the lower shaft conveying sprocket 7a of the present stage and the rear side of the upper shaft conveying sprocket 8a of the present stage, and the lower edge of the scraper descends against the baffle plate 4 and ascends against the inclined bottom plate 3 c.

The conveying chain 13 goes upward along a tangent line between the front side of the lower shaft conveying sprocket of the present stage and the rear side of the upper shaft conveying sprocket 8a of the present stage, and goes downward along a tangent line between the front side of the upper shaft conveying sprocket 8a of the present stage and the rear side of the lower shaft conveying sprocket of the previous stage. The plane of the lower shaft axis of the stage and the plane of the upper shaft axis of the stage are intersected with the inclined bottom plate of the stage and the baffle plate 4 at an acute angle.

Taking six-stage extraction as an example, a first-stage soaking tank is close to the wet dreg outlet 1d, a sixth-stage soaking tank is far away from the wet dreg outlet 1d, a first-stage lower shaft is positioned at the bottom of the first-stage soaking tank, a second-stage lower shaft is positioned at the bottom of the second-stage soaking tank, and the like, and a sixth-stage lower shaft is positioned at the bottom of the sixth-stage soaking tank.

The upper shaft of the sixth stage is positioned at a position above and in front of the soaking tank of the fifth stage, the upper shaft of the fifth stage is positioned at a position above and in front of the soaking tank of the fourth stage, and the like, the upper shaft of the second stage is positioned at a position above and in front of the soaking tank of the first stage, and the heights of the upper shafts of the second to sixth stages are the same. The first stage upper shaft is used as a discharging shaft 8-3, the axial height of which is higher than that of the second to sixth stage upper shafts, and is positioned above the wet meal outlet 1 d.

The conveying chain 13 turns to the upward and around the conveying chain wheel of the sixth-stage lower shaft from the upper slope, turns to the upward and around the conveying chain wheel of the sixth-stage upper shaft, turns to the downward and around the conveying chain wheel of the fifth-stage lower shaft, turns to the upward and around the conveying chain wheel of the fifth-stage upper shaft again, pushes away in this way, turns to the downward and around the conveying chain wheel of the first-stage lower shaft after around the conveying chain wheel of the second-stage upper shaft, turns to the upward again, turns to the upward through the discharging side guide slide rail 1k, enters into the conveying chain wheel of the first-stage upper shaft, namely the discharging shaft 8-3, turns to the rear through the discharging shaft conveying chain wheel, enters into the empty horizontal section to advance to the feeding side, turns to the rear through the feeding side guide slide rail 1j, and turns to the conveying chain wheel which bypasses the sixth-stage lower shaft downwards to form a closed loop.

The conveying chains 13 on two sides of the inner cavity of the box body 1 are all whole chains to form a group, two ends of the scraping plate 13a are respectively fixed on corresponding chain links of the conveying chains 13, the scraping plate 13a is uniformly arranged along the circumference of the conveying chains 13, and the scraping plate 13a pushes materials to advance along with the rotation of the conveying chains 13.

As shown in fig. 7, since each stage of soaking units shares a set of conveying chains 13, there is no speed difference along the circumference of the conveying chains 13, and the risk of blockage is greatly reduced. The device adopts a single speed reducer 10 for driving, and a control system is greatly simplified.

In order to reduce the stress of the conveying chain 13 in the box body, reduce abrasion and improve reliability, an external serial transmission chain is adopted for transmission. Namely, the speed reducer 10 transmits torque to the main driving shaft 8-1, and the main driving shaft 8-1 is transmitted to the auxiliary driving shaft 8-2 through the auxiliary transmission chain 12, so that the conveying chain 13 in the box body is always in a very small load state, and very high reliability is realized.

Example 1

The speed reducer 10 is installed at the feeding end of the top of the box body, an upper shaft near the feeding end, for example, a sixth-stage upper shaft is used as a main driving shaft 8-1, and an upper shaft located in the middle and an upper shaft near the discharging end are used as auxiliary driving shafts 8-2.

The shaft end of the main driving shaft 8-1 is provided with a large chain wheel 8-1a and a main driving chain wheel 8-1b, the shaft end of the auxiliary driving shaft 8-2 is provided with an auxiliary driving chain wheel 9, the output chain wheel of the speed reducer 10 is connected with the large chain wheel 8-1a of the main driving shaft 8-1 through a speed reducer transmission chain 11, and the main driving chain wheel 8-1b of the main driving shaft 8-1 is connected with the auxiliary driving chain wheel 9 on the auxiliary driving shaft 8-2 through an auxiliary transmission chain 12.

The speed reducer 10 drives a large chain wheel 8-1a on the main driving shaft 8-1 through a speed reducer transmission chain 11, and transmits torque to the main driving shaft 8-1 while realizing speed reduction, and the main driving chain wheel 8-1b drives the auxiliary driving chain wheel 9 and the auxiliary driving shaft 8-2 to rotate through an auxiliary transmission chain 12. For example, the sixth-stage upper shaft drives the fourth-stage upper shaft to rotate through the auxiliary transmission chain 12, and the fourth-stage upper shaft drives the second-stage upper shaft to rotate through the auxiliary transmission chain 12.

Example two

The speed reducer is arranged at the discharge end of the top of the box body, an upper shaft close to the discharge end, such as a second-stage upper shaft, is used as a main driving shaft, and an upper shaft positioned in the middle and an upper shaft close to the feed end are used as auxiliary driving shafts 8-2.

The speed reducer drives a second-stage upper shaft serving as a main driving shaft to rotate, the second-stage upper shaft drives a fourth-stage upper shaft to rotate through an auxiliary transmission chain, and the fourth-stage upper shaft drives a sixth-stage upper shaft to rotate through the auxiliary transmission chain.

Example III

The speed reducer is installed at the middle position of the top of the box body, an upper shaft close to the middle extraction unit, such as a fourth-stage upper shaft, is used as a main driving shaft, and an upper shaft close to the feeding end and an upper shaft close to the discharging end are used as auxiliary driving shafts 8-2.

The speed reducer drives the fourth-stage upper shaft to rotate, the fourth-stage upper shaft forwards drives the second-stage upper shaft to rotate through the auxiliary transmission chain, and meanwhile, the sixth-stage upper shaft is backwards driven to rotate through the auxiliary transmission chain.

The baffle plates 4 are solid plates and are inserted in each soaking tank, are parallel to each inclined bottom plate 3c, the upper ends of the baffle plates are higher than the liquid level, the lower ends of the baffle plates are inserted into the lower parts of the soaking tanks, the extraction liquid at the front parts of the soaking tanks is forced to bypass the lower edges of the baffle plates 4, and can reach the rear parts of the soaking tanks after fully contacting and exchanging with materials, so that the flow path length of the extraction liquid is prolonged. The upper layer low concentration extract is prevented from flowing backwards directly, the effective working path is long, and the short circuit phenomenon is avoided.

The baffle plates 4 at each stage have another function, and form a downlink tunnel of the material with the lower end face of the inclined bottom plate at the later stage, and form an uplink tunnel of the material with the upper end face of the inclined bottom plate at the previous stage. Ensuring that the solvent solute is in countercurrent contact in a tunnel formed by the inclined bottom plate of the soaking tank and the baffle plate 4, and the tortuous tunnel limits the movement path of solid materials and extraction liquid, increases the frequency, path and duration of countercurrent contact of the solute and the solvent, and strengthens the mass transfer process of extraction. The cascade tunnel countercurrent soaking forms the dominant extraction process for powdery or semi-fluid solid materials.

Two feed inlets are arranged at the rear part of the top wall of the box body, a solid material feed inlet 1a is arranged at the rear side and is positioned above the final baffle plate, and the box body can be used for feeding solid materials. The solid material feed inlet 1a is equipped with temporary storage bucket 1m, utilizes temporary storage bucket 1m accumulative material to realize in the container with the atmosphere isolation, prevents that volatile solvent from escaping in the container and leading to harm or loss.

The feeding adjusting gate 2 is arranged at the rear upper part of the final baffle plate, and the distance between the gate height control and the final baffle plate can be adjusted, so that the feeding amount is controlled, and the tunnel siltation and blockage caused by out-of-control feeding is prevented. The shallow material layer is generally adopted for soaking and extraction, and the height of the material layer is controlled to be 100-400mm according to the properties of the material.

The other feed inlet is a semi-fluid material feed inlet 1b, which is positioned at the front side of the solid material feed inlet 1a, and aims at semi-fluid materials with strong fluidity, such as thick paste and semi-slurry materials. A feeding platform 1c is arranged below the semi-fluid material feeding port 1b, and the feeding platform 1c is positioned above the last-stage upper shaft and can bear materials with strong fluidity.

The continuous extraction generally adopts six-stage extraction, solid raw materials fall into a sixth-stage soaking tank through a solid material feed inlet 1a, are pushed by a scraper to descend along a baffle plate of the sixth stage to contact with concentrated mixed oil in the sixth-stage soaking tank, solid materials fall into an arc-shaped bottom 3b of the sixth-stage soaking tank from the bottom of the baffle plate, are fished up and pushed by a chain scraper device, ascend along an inclined bottom plate of the sixth stage and are separated from a liquid level, the solid materials are drained, free mixed oil in the solid materials is discharged, then fall into a baffle plate of the fifth stage from the inclined bottom plate of the sixth stage, are pushed by the scraper to descend along the baffle plate of the fifth stage to contact with the concentrated mixed oil in the fifth-stage soaking tank, and the like, so that continuous extraction is carried out. The number of stages can be increased appropriately for materials that are difficult to extract.

The inclined bottom plate 3c is higher and longer, is close to the upper shaft, is obviously higher than the liquid surface, and is higher than the inclined plate section of the liquid surface for draining wet meal, so that the thick mixing content in the wet meal is reduced, the concentration gradient of each stage of soaking tank is obvious, and each stage of extraction has larger extraction power.

The inclined bottom plate 3c of each stage of soaking tank is provided with an obvious draining section, so that concentrated extract liquid in the solid material is fully drained before the solid material enters the next stage of soaking, concentration gradient is easily formed in each stage of soaking tank, and the extract liquid has larger extraction power.

The upper end of the inclined bottom plate 3c can be higher than the horizontal plane of the upper shaft axis so that the box body has higher liquid level, has longer upward extraction stroke along the inclined bottom plate 3c, and has longer downward extraction stroke along the baffle plate 4 after falling onto the baffle plate of the previous stage from the top of the inclined bottom plate 3 c.

The baffle plate of the present stage extends from the front side of the upper shaft of the subsequent stage to the top of the lower shaft 7 of the present stage, the upper end of the baffle plate 4 can approach the horizontal plane where the axis of the upper shaft is located, and a small amount of materials which pass over the upper shaft chain wheel can also be received by the baffle plate 4 and enter the downlink tunnel for extraction.

The upper parts of the inclined bottom plates 3c of each stage except the first stage are respectively provided with a filtering grid plate 3d, and the filtering grid plates 3d are of a structure with narrow upper part and wide lower part, so that blockage is avoided. The lower edge of the filtering grid plate of the previous stage is higher than the lower edge of the filtering grid plate of the next stage in sequence, the position of the filtering grid plate of the new dissolution side is highest, the filtering grid plate of the dense mixing side is gradually lowered, and the lower edge of the filtering grid plate 3d of each stage is higher than the top of the wallboard 3a of the soaking tank of the previous stage.

Under the action of the inter-stage liquid level difference, the high-position extraction liquid at the low concentration side penetrates through the filtering grid plate 3d and simultaneously penetrates through the solid material on the filtering grid plate 3d, so that the primary washing of the solid material and the replacement of the concentrated extraction liquid in the solid material are realized, and the original concentration balance in the solid material is broken, thereby being beneficial to establishing new mass transfer balance when entering the next stage of soaking.

The solid materials can be drained quickly at the upper part of each stage of filter grid plate 3 d. The filter grid 3d may extend to the top of the inclined bottom plate 3c, and may be arranged in sections or integrally in the width direction of the inclined bottom plate 3 c.

The inclined bottom plate of the first-stage soaking tank is not provided with a filtering grid plate, but the height is higher, so that the material is drained thoroughly before discharging.

The first stage soaking tank is close to the wet dreg outlet, a thick mixing reflux port 1n is arranged above the last stage soaking tank, and the bottom outlets of the cyclone separation device E11 and the thick mixing tank E12 are connected with the thick mixing reflux port 1 n.

The new solution spray pipe 15 is arranged above the first-stage soaking tank, the nozzle of the new solution spray pipe 15 can be aligned to the junction of the wet meal of the first-stage soaking tank and the liquid level, and the wet meal separated from the first-stage soaking tank is washed again by using the new solution and enters the final draining section. The new solution spraying pipe 15 can be arranged at the top of the box body and above the conveying chain 13 in the empty horizontal section, and the sprayed new solution can clean the conveying chain 13 and the scraping plate thereof and enter the next cycle.

Taking six-stage extraction as an example, fresh solvent is sprayed into a material ascending tunnel of a first-stage soaking tank, after mass transfer is fully mixed with solid phase to be discharged, the new solvent reversely flows downwards, enters the material descending tunnel of the first stage from the lower edge of a first-stage baffle plate and the bottom of the first-stage soaking tank, flows upwards along the material descending tunnel formed by the first-stage baffle plate and a second-stage inclined bottom plate, penetrates or permeates solid materials at a filtering grid plate section of the second-stage inclined bottom plate, enters the second-stage soaking tank, and finally flows into a sixth-stage soaking tank.

The inclined bottom plates of the soaking tanks are uniformly provided with filtering grid plates 3d, and gravity flow is realized by utilizing liquid level difference. The fresh solvent and the solid phase are in countercurrent contact, the fresh solvent is injected continuously on the fresh solvent side, the liquid level is at a high level, and the concentrated solvent side is at a low level due to the fact that the set liquid level is at a low level, so that obvious liquid level difference is formed in the equipment, and the liquid continuously permeates and flows from the high level to the low level. The side wall of the first-stage soaking tank is provided with a tank overflow port 1e for controlling the highest liquid level so as to ensure safety.

The rear wall of the final-stage soaking tank is provided with a thick mixing outlet 3e, the front side of the thick mixing outlet 3e is provided with a baffle plate 5 penetrating into the liquid surface, the thick mixing outlet 3e is separated from the descending materials, a thick mixing sedimentation zone 6 is formed between the baffle plate 5 and the rear wall of the final-stage soaking tank, and after powder sedimentation, thick dissolution is discharged. The solute concentration of the extract liquid of the final soaking tank is 30-40%, the average concentration is 35%, the concentration of the extract liquid of the fifth stage is about 25%, the concentration of the extract liquid of the fourth stage is about 16%, the concentration of the extract liquid of the third stage is about 8%, the concentration of the extract liquid of the second stage is about 3%, and the concentration of the extract liquid of the first stage is about 0.5-1%. Because the oil content of the palm kernel is high, the leaching stage number is not limited to six when the palm kernel is directly leached, and more than eight stages of leaching and draining are more likely to be selected.

Each stage of extraction process of the material comprises the following steps: immersing, mixing solid and liquid, fishing out, and draining. The highest concentration of solute in the new solid material is contacted with the concentrated solution with the highest concentration, so that the extraction power is higher; the solute concentration in the discharged solid material is the lowest and the new solution with the lowest concentration is in contact, the solid material still has higher extraction power, the solid material is finally fully mixed with the fresh solvent in the first-stage soaking tank, and then the solid material is fished up by a scraper and drained, and is discharged from the wet meal outlet 1 d.

The top of the box is also provided with a free gas port 1f and an access door 1g. Each is connected with an exhaust gas condenser E20 through a pipeline by a gas interface 1 f.

The lowest part of the arc-shaped bottom 3b of each soaking tank is respectively provided with an emptying port, and each emptying port is connected into the emptying pipe 14, so that the emptying is convenient for overhauling or replacing batches.

As shown in fig. 8, because of the phase difference between the internal conveying sprocket and the external auxiliary driving sprocket 9 on the auxiliary driving shaft 8-2, when the conveying sprocket is properly tensioned, the phases of the auxiliary driving sprocket 9 and the matched sprocket need to be randomly adjusted so as to meet the meshing requirement of the external auxiliary transmission chain. An expansion sleeve is arranged in the central hole of the auxiliary drive sprocket 9, specifically an inner conical expansion sleeve 9a is abutted against the step in the central hole, an outer conical expansion sleeve 9b is inserted into and matched with the inner conical expansion sleeve 9a, the outer conical expansion sleeve 9b is sleeved on the corresponding auxiliary drive shaft 8-2, a plurality of expansion screws 9c are uniformly distributed on the outer end face of the outer conical expansion sleeve 9b, and the inner end head of each expansion screw 9c is screwed into a screw hole of the inner conical expansion sleeve 9 a.

The expansion screw 9c is loosened, and the phase angle can be adjusted at will according to the requirement; after the adjustment is in place, the expansion screws 9c can be tightened to tighten the expansion sleeve. The structure can effectively transmit torque and is convenient to assemble and disassemble.

The device can still continuously run even if the special working condition that the expansion sleeve of the external auxiliary drive sprocket wheel 9 slips occurs. The load traction is changed from an external drive chain to an internal conveyor chain 13. Short-term operation is free of problems, fault emergency stop is avoided, and reliability and safety of equipment are improved. The long-term operation can increase the abrasion of the built-in conveying chain 13, and the maintenance is preferably performed as soon as possible by utilizing the production gap.

As shown in FIG. 9, the auxiliary driving shaft 8-2 is provided with a stall warning mechanism, and the stall warning mechanism can take various forms, for example, a sensing piece 8-2a is arranged at the shaft end of the auxiliary driving shaft 8-2, a plurality of signal teeth are uniformly arranged on the circumference of the sensing piece 8-2a, and a proximity switch 8-2b or an encoder detects the rotating speed of the sensing piece 8-2a and provides the rotating speed to a control system. When the expansion sleeve just slips, the auxiliary driving shaft 8-2 can instantaneously stall, a stall alarm mechanism sends out an alarm signal, and the control system sends out an alarm signal to inform an operator of working conditions, so that the maintenance and the repair are convenient.

As shown in fig. 10 to 13, the lower shaft 7 comprises an immersed section in the immersion tank and shaft heads at two ends, the two ends of the immersed section are respectively provided with a finished large-diameter section, the circumference of the large-diameter section is respectively sleeved with a lower shaft conveying chain wheel 7a, the inner hole of the lower shaft conveying chain wheel 7a is fixed on the large-diameter section through a flat key, a flange of the lower shaft conveying chain wheel 7a is screwed with a set screw to be abutted against the flat key, the immersed sections of the two lower shaft conveying chain wheels 7a and the lower shaft 7 are immersed in a solvent, and the immersed sections are positioned in the immersion tank and close to two side walls and are used for driving a chain, and a scraper uniformly fixed on the chain turns around the axis of the lower shaft 7 and drives materials at the bottom of the immersion tank to go upward.

The two shaft heads respectively penetrate through the side wall of the soaking tank, a left-hand bushing 7b is sleeved on the left-hand shaft head, and left-hand threads 7b1 are arranged on the periphery of the left-hand bushing 7 b; a right-hand bushing 7c is sleeved on the right-hand spindle, right-hand threads 7c1 are arranged on the periphery of the right-hand bushing 7c, and the left-hand bushing and the right-hand bushing are matched for use; the inner ends of the left-hand bushing 7b and the right-hand bushing 7c respectively abut against shoulders of the root of the stub shaft.

The left-handed bush 7b and the right-handed bush 7c are in interference fit with the corresponding shaft heads, and the outer walls of the left-handed bush 7b and the right-handed bush 7c are respectively in clearance fit with the inner holes of the corresponding sliding bearings 7 d.

The rotation speed of the lower shaft 7 is extremely low, usually in the range of 0.1-0.5rpm, the left-handed bushing 7b and the right-handed bushing 7c can be made of martensitic stainless steel, the sliding bearing 7d can be made of spheroidal graphite cast iron and other materials, and a loose matching relationship is adopted. Because the lower shaft 7 is lightly loaded and has extremely slow rotating speed, the sliding bearing 7d also meets the service life requirement under the condition of no lubrication;

when the lower shaft 7 rotates, the left-handed threads 7b1 are discharged to the right, namely, are discharged into a soaking tank where the immersed section is positioned; the right-hand threads 7c1 are discharged to the left and also to the soaking tank in which the submerged section is located. The left-handed threads 7b1 and the right-handed threads 7c1 are trapezoidal threads, and the trapezoidal threads at the two ends continuously push the entering powder outwards, so that the powder is prevented from being deposited on the inner wall of the sliding bearing 7d, and friction force is increased or locking is prevented.

The outer walls of the two sliding bearings 7d are respectively embedded in the corresponding lower shaft bearing seats 7e, the outer peripheries of the root parts of the sliding bearings 7d are respectively provided with a sliding bearing outer flange 7d1, and the sliding bearing outer flanges 7d1 are respectively embedded in inner ring grooves of the corresponding lower shaft bearing seats 7e, so that the axial positioning of the sliding bearings 7d and the lower shaft bearing seats 7e is realized.

The outer ports of the two lower shaft bearing seats 7e are respectively covered with a blank cap 7g, the inner end surfaces of the blank caps 7g are respectively provided with a blank cap inner convex ring 7g1, and the blank cap inner convex rings 7g1 are respectively embedded into the outer ports of the corresponding lower shaft bearing seats 7e, so that the automatic centering of the blank caps 7g and the lower shaft bearing seats 7e is facilitated, and the sealing performance is improved; a gap is reserved between the inner convex ring 7g1 of the cover and the outer end surface of the lining.

The outer port of the lower shaft bearing seat 7e is uniformly provided with a plurality of screw holes for fixing, the outer circumference of the blank cap 7g is uniformly provided with a plurality of blank cap fixing holes, a blank cap sealing gasket 7g3 is respectively arranged between the outer port of the lower shaft bearing seat 7e and the outer circumference of the blank cap 7g, each blank cap screw 7g2 respectively penetrates through the blank cap fixing holes and the through holes on the blank cap sealing gasket 7g3 to be screwed into the corresponding screw holes of the lower shaft bearing seat 7e, and the blank cap 7g is fixed on the lower shaft bearing seat 7e and mutually seals the two.

The root parts of the two lower shaft bearing seats 7e are respectively inserted into the central holes of the corresponding lower shaft flange sealing discs 7f, so that the accurate central positioning of the two lower shaft bearing seats is realized. The outer periphery of the lower shaft bearing seat 7e, which is close to the root, is respectively provided with a lower shaft bearing seat outer flange 7e1, and a lower shaft bearing seat sealing gasket 7h is arranged between the opposite end surfaces of the lower shaft bearing seat outer flange 7e1 and the lower shaft flange sealing disc 7 f. The outer end face of the lower shaft flange sealing disc 7f and the corresponding part of the outer flange 7e1 of the lower shaft bearing seat are provided with a lower shaft flange sealing disc center outer sinking groove, and half thickness of the lower shaft bearing seat sealing gasket 7h is embedded in the lower shaft flange sealing disc center outer sinking groove so as to quickly and accurately realize positioning.

A plurality of lower shaft bearing seat fixing holes are uniformly distributed on the lower shaft bearing seat outer flange 7e1, and each lower shaft bearing seat screw 7e2 respectively penetrates through the lower shaft bearing seat fixing hole and a through hole on the lower shaft bearing seat sealing gasket 7h to be screwed into a corresponding screw hole of the lower shaft flange sealing disc 7f, so that the lower shaft bearing seat 7e is fixedly connected to the lower shaft flange sealing disc 7f and mutually sealed.

The outer edges of the inner end surfaces of the two lower shaft flange sealing plates 7f are respectively provided with a lower shaft flange sealing plate inner ring groove, and lower shaft flange sealing gaskets 7j are respectively embedded in the lower shaft flange sealing plate inner ring grooves, so that the lower shaft flange sealing gaskets 7j are conveniently sleeved on the lower shaft flange sealing plates 7f in advance and automatically ensure centering, and the lower shaft flange sealing gaskets 7j are respectively pressed on the outer walls of the soaking grooves to realize sealing.

The periphery of the two lower shaft flange sealing plates 7f are uniformly provided with a plurality of lower shaft flange sealing plate fixing holes, and each lower shaft flange sealing plate screw penetrates through the corresponding lower shaft flange sealing plate fixing hole and the corresponding through hole on the lower shaft flange sealing plate gasket 7j and is screwed into the screw hole on the side wall of the soaking tank, so that the lower shaft flange sealing plates are fixed on the side wall of the soaking tank in a sealing manner.

During installation, the lower shaft flange sealing plates 7f can be fixed, and then the lower shaft 7 can be installed. When the lower shaft 7 is installed, the left-handed bushing 7b and the right-handed bushing 7c can be preheated and sleeved on two shaft heads of the lower shaft 7, and the left-handed bushing and the right-handed bushing are automatically held tightly after being cooled to realize interference fit; then, the lower shaft conveying chain wheels 7a are arranged at the two ends of the immersed section of the lower shaft 7, the lower shaft 7 is integrally hoisted and placed into the inner cavity of the soaking tank, and the two ends of the lower shaft 7 extend out of the central hole of the lower shaft flange sealing disc.

When the shaft end is installed, firstly, the sliding bearing 7d is embedded in the lower shaft bearing seat 7e, the lower shaft bearing seat sealing gasket 7h is embedded in the outer sinking groove of the center of the lower shaft flange sealing disc, then the sliding bearing 7d is sleeved on the corresponding bushing, the sliding bearing is pushed inwards until the inner end of the lower shaft bearing seat 7e is inserted into the center hole of the lower shaft flange sealing disc, then, each lower shaft bearing seat screw 7e2 is screwed in, and the lower shaft bearing seat 7e is fixed on the lower shaft flange sealing disc 7 f; finally, the blank cap seal 7g3 and the blank cap 7g are installed.

After long-time operation, the left-handed bushing 7b, the right-handed bushing 7c, the sliding bearing 7d or the lower shaft conveying sprocket 7a can be replaced, the lower shaft 7 and other parts do not need to be replaced, spare part loss is low, and the sequence during disassembly is opposite to that during installation.

As shown in fig. 14 to 17, the feed adjusting gate 2 includes a worm gear driver 2b, a drive shaft 2c, a drive shaft bearing housing 2d, a drive sleeve 2e, a driving swing plate 2f, an arc shutter plate 2g, a driven swing plate 2j, a driven shaft 2k, and a driven end bearing housing 2m, a worm is driven by a worm in the worm gear driver 2b to rotate, a hand wheel 2a is mounted at the drive end of the worm shaft, and the drive shaft 2c is fixed at the center of the worm gear. The middle section of the transmission shaft 2c is supported in the center of the gate flange sealing plate 2n in a sealing way through a transmission shaft bearing seat 2 d.

The shell of the worm gear driver 2b is fixedly connected with a rotation stopping arm 2b1, the outer wall of a transmission shaft bearing seat 2d is welded with a transmission shaft bearing seat supporting lug 2d1, the outer end head of the rotation stopping arm 2b1 is fixedly connected with the transmission shaft bearing seat supporting lug 2d1 through a rotation stopping bolt, a spacer bush is sleeved on the periphery of the middle section of the rotation stopping bolt, the spacer bush is supported between the opposite end surfaces of the rotation stopping arm 2b1 and the transmission shaft bearing seat supporting lug 2d1, and after nuts of the rotation stopping bolt are screwed, the worm gear driver 2b, the transmission shaft bearing seat 2d and a gate flange sealing plate 2n are relatively fixed.

The two ports of the transmission shaft bearing seat 2d are respectively fixed with a gland 2d2, the outer end of the gland 2d2 is provided with a gland flange, the gland flange is fixed on the port of the transmission shaft bearing seat 2d through gland screws, and gland gaskets are respectively arranged between the gland flange and the port of the transmission shaft bearing seat 2d to ensure the port to be sealed.

The centers of the two pressing covers 2d2 are respectively provided with a pressing cover center sleeve, the two pressing cover center sleeves are inserted into the inner cavity of the transmission shaft bearing seat 2d in the opposite direction, the inner cavities of the pressing cover center sleeves are respectively provided with a bearing bush 2d3, the bearing bushes 2d3 are copper-based solid lubrication bearings and are respectively sleeved on the transmission shaft 2c, the maximum diameter section of the transmission shaft 2c is arranged between the two bearing bushes 2d3, and the maximum diameter section is positioned in the middle of the inner cavity of the transmission shaft bearing seat 2 d. An inner step is arranged in the gland center hole, and the two bearing bushes 2d3 respectively lean against the inner side of the step in the gland center hole.

The transmission shaft sealing rings 2d4 are embedded in the outer ports of the two pressing covers 2d2 respectively, the transmission shaft sealing rings 2d4 are skeleton oil seals, at least two transmission shaft sealing rings are arranged at each end, the sealing reliability is guaranteed, and the skeleton oil seal which is close to the inside is abutted against the outer side of the step in the center hole of the pressing cover.

The middle part of the transmission shaft bearing seat 2d is welded in the central hole of the gate flange sealing plate 2n, the gate flange sealing plate 2n is circular, a plurality of flange bolt holes are uniformly distributed on the periphery, and each screw penetrates through the flange bolt hole to fix the gate flange sealing plate 2n on a side wall plate of the leacher. The inner end face of the gate flange sealing plate 2n is provided with a sealing plate positioning boss 2n1, the sealing plate positioning boss 2n1 is embedded into the mounting hole of the leachable wallboard, so that the rapid centering of the gate flange sealing plate 2n and the mounting hole is conveniently realized, and a gate sealing plate sealing gasket 2p is arranged between the flange edge of the gate flange sealing plate 2n and the leachable wallboard to realize sealing.

The inner end of the transmission shaft 2c is provided with a conical section and a threaded section, the conical section is sleeved with a transmission sleeve 2e, an inner conical hole of the transmission sleeve 2e is matched with the conical section of the transmission shaft 2c, the threaded section of the transmission shaft 2c is screwed with a locking nut 2c1, the outer side of the locking nut 2c1 is screwed with a nut cap, the locking nut 2c1 is tightly pressed on the end face of the transmission sleeve 2e through a gasket, and the transmission sleeve 2e is fixed on the transmission shaft 2 c.

The outer Zhou Gulian of the transmission sleeve 2e is provided with two driving swing plates 2f which can be parallel to each other, and the free ends of the two driving swing plates 2f are fixedly connected with one end of the arc-shaped flashboard 2 g. The active swinging plate 2f is a sector-shaped arc plate, and the outer edge of the arc can be welded with the inner arc surface of the arc flashboard 2 g.

The other end of the arc-shaped flashboard 2g is fixedly connected with a driven swinging plate 2j, the driven swinging plate 2j is also a sector-shaped arc plate, two parallel arc plates can be arranged, and the arc-shaped outer edge of the driven swinging plate can be welded with the intrados of the arc-shaped flashboard 2 g. The driven shafts 2k are inserted into the center holes of the two driven swing plates 2j, the arc-shaped flashboard 2g is coaxial with the transmission shaft 2c and the driven shafts 2k, the driven shafts 2k are supported in driven end bearing seats 2m, and the driven end bearing seats 2m are fixed on the inner side of the wall plate on the other side of the leacher.

The inner cambered surface of the arc-shaped flashboard 2g is welded with a rib plate 2h, and the rib plate 2h is positioned between the driving swing plate 2f and the driven swing plate 2 j. The rib plate 2h is of a trapezoid cross section, the top edge of the outer protrusion is outwards, the upper edge and the lower edge are welded with the inner cambered surface of the arc-shaped flashboard 2g, and a plurality of emptying gaps 2h1 are uniformly formed in the lower edge, so that accumulation in the rib plate 2h is prevented.

The radius of the sealing plate positioning boss 2n1 is larger than the turning radius of the arc-shaped flashboard 2g, so that the adjusting gate is convenient to install or detach from the mounting hole on one side of the leacher.

In the operation process of the leacher, when the feeding amount is required to be regulated, the hand wheel 2a can be directly rotated to regulate without any disassembly, the hand wheel 2a rotates for a circle, the worm wheel drives the transmission shaft 2c to rotate a phase angle of one tooth, the transmission shaft 2c drives the arc-shaped flashboard 2g to rotate by the same phase angle through the transmission sleeve 2e and the driving swing plate 2f, and the lower edge of the arc-shaped flashboard 2g cuts into or withdraws from the feeding channel more so as to regulate the feeding amount. The outer wall of the worm gear driver 2b is provided with a dial for indicating the opening degree of the arc flashboard 2g, so that the precise control is facilitated.

In the adjusting process, the driven shaft 2k related to sealing only needs to rotate, does not need to axially move, the rotating angle of each time of adjustment is very small, is usually not more than 45 degrees, does not need to continuously rotate for a plurality of weeks, and the framework oil seal is not easy to wear, and is very long in service life, reliable in sealing and high in safety.

The foregoing description of the preferred embodiments of the present invention illustrates and describes the basic principles and main features of the present invention and the advantages of the present invention, and is not meant to limit the scope of the present invention, as it should be understood by those skilled in the art that the present invention is not limited to the above-described embodiments. In addition to the embodiments described above, other embodiments of the invention are possible without departing from the spirit and scope of the invention. The invention also has various changes and improvements, and all technical schemes formed by adopting equivalent substitution or equivalent transformation fall within the protection scope of the invention. The scope of the invention is defined by the appended claims and equivalents thereof. The technical features of the present invention that are not described may be implemented by or using the prior art, and are not described herein.

Claims

1. The utility model provides a palm kernel direct leaching system, includes palm kernel temporary storage bin, its characterized in that, palm kernel temporary storage bin's export links to each other with the entry of breaker, the export of breaker links to each other with the entry of embryo rolling machine, the export of embryo rolling machine links to each other with the entry of quantitative auger through conveying mechanism, the export of quantitative auger links to each other with the temporary storage bucket entry of step tunnel type leacher, the thick mixed export of step tunnel type leacher links to each other with cyclone separation device's entry through thick mixed pump I, cyclone separation device's top export links to each other with the entry of thick mixed jar, thick mixed jar's lower part export links to each other with extract evaporation recovery system's thick extract entry through thick mixed jar pump II, extract evaporation recovery system's retrieval and reuse solvent export links to each other with step tunnel type leacher's new-soluble shower through fresh solvent pump;

the rear end of the box body of the cascade tunnel type leacher is a feeding end, and a wet dreg outlet is positioned at the front end of the box body; the box body inner cavity is sequentially provided with a plurality of stages of soaking units from front to back, each stage of soaking units respectively comprises a soaking tank, a lower shaft and an upper shaft, each lower shaft is respectively positioned at the bottom of the corresponding stage of soaking tank, each stage of upper shaft is respectively positioned above the previous stage of soaking tank, the first stage of upper shaft is positioned above a wet meal outlet, a conveying chain is S-shaped and sequentially and alternately bypasses conveying chain wheels of each stage of lower shaft and upper shaft, the conveying chain wheel of the first stage of upper shaft bypasses the conveying chain wheel of the last stage of lower shaft again to form a closed loop through a guide sliding rail at the feeding side, and scraping plates are uniformly arranged along the circumference of the conveying chain;

Each stage of soaking tank respectively comprises a wallboard, an arc bottom and an inclined bottom plate which are connected into a whole in sequence, the lower shaft of the stage is immersed in the arc bottom of the soaking tank of the stage, the upper end of the inclined bottom plate extends towards the rear side of the upper shaft of the stage, and the upper end of the wallboard is connected below the inclined bottom plate of the soaking tank of the subsequent stage.

2. The palm kernel direct leaching system of claim 1, wherein: the wet dreg outlet of the step tunnel type leacher is connected with the inlet at the lower end of the wet dreg bent scraper, the outlet at the upper end of the wet dreg bent scraper is connected with the feeding port of the vertical type steam-off machine, the discharging port of the vertical type steam-off machine is connected with the inlet at the lower end of the dry dreg scraper, the outlet at the upper end of the dry dreg scraper is connected with the inlet of the classifying screen, the outlet at the lower end of the classifying screen is provided with the outlet of the palm kernel finished dreg, and the outlet at the upper end of the classifying screen is connected with the inlet of the crusher.

3. The palm kernel direct leaching system of claim 1, wherein: the first stage soaking tank is close to the wet dreg outlet, a dense mixing reflux port is arranged above the last stage soaking tank, and the bottom outlets of the cyclone separation device and the dense mixing tank are connected with the dense mixing reflux port.

4. A palm kernel direct leaching system according to claim 3, wherein: the upper parts of the inclined bottom plates of all levels except the first level are respectively provided with a filtering grid plate, and the lower edge heights of the filtering grid plates are gradually reduced from front to back and are higher than the tops of the wallboards;

The soaking units of each level are also respectively provided with baffle plates, each baffle plate is a solid plate parallel to the inclined bottom plates of each level, the upper ends of the baffle plates are higher than the liquid level, and the lower ends of the baffle plates are inserted into the lower part of the soaking tank;

the baffle plates of each stage and the lower end face of the inclined bottom plate of the subsequent stage form a downlink tunnel of materials, and the baffle plates of each stage and the upper end face of the inclined bottom plate of the previous stage form an uplink tunnel of materials; the scraping plate descends along the baffle plate and ascends along the inclined bottom plate.

5. The direct palm kernel leaching system of claim 4, wherein: the baffle plate of the present stage extends from the front side of the upper shaft of the following stage to the top of the lower shaft of the present stage; the plane of the lower shaft axis of the present stage and the plane of the upper shaft axis of the present stage are intersected with the inclined bottom plate of the present stage and the baffle plate at an acute angle; the upper end of the inclined bottom plate is higher than the horizontal plane where the axis of the upper shaft is located, and the upper end of the baffle plate is close to the horizontal plane where the axis of the upper shaft is located.

6. The palm kernel direct leaching system of claim 1, wherein: the new solution spray pipe is sprayed to the middle section of the inclined bottom plate of the first-stage soaking tank; the liquid level of the former stage soaking tank is higher than that of the latter stage soaking tank, the thick mixing outlet is positioned on the rear wall of the last stage soaking tank, a baffle plate penetrating into the liquid level is arranged at the front side of the thick mixing outlet, and a thick mixing sedimentation zone is formed between the baffle plate and the rear wall of the last stage soaking tank.

7. The direct palm kernel leaching system of claim 4, wherein: the bottom of the temporary storage hopper is in butt joint with a solid material inlet at the rear part of the top wall of the box body, and the solid material inlet is positioned above the final baffle plate; the front of the solid material feed inlet is provided with a semi-fluid material feed inlet, the lower part of the semi-fluid material feed inlet is provided with a feed platform, and the feed platform is positioned above the last-stage upper shaft.

8. The palm kernel direct leaching system of claim 1, wherein: a certain upper shaft is used as a main driving shaft, and the main driving shaft is driven by a speed reducer; the rest part or all of the upper shafts are used as auxiliary driving shafts, and the auxiliary driving shafts are synchronously driven by the main driving shafts; the auxiliary driving chain wheel is arranged at the shaft end of the auxiliary driving shaft through the expansion sleeve.

9. The direct leaching process of palm kernel adopts the cascade tunnel type leacher according to any one of claims 1 to 8, and is characterized in that the palm kernel is crushed into 8-10 pieces by a crusher, rolled into embryo pieces with the thickness of 0.25-0.35MM, then falls into a final soaking tank of the cascade tunnel type leacher, is mixed with extract with the solute concentration of 30-40%, is fished out from the final soaking tank, then falls into a previous soaking tank in sequence for gradual extraction, finally falls into a first soaking tank, is mixed with fresh extract with the solute concentration of 0.5-1%, is drained, is sieved after solvent is evaporated, and the above-2 MM-sieve particles return to the crusher for crushing, and the below-2 MM-sieve finished product meal is drained; and (3) carrying out solid-liquid separation on the concentrated mixture discharged from the final-stage soaking tank, returning the solid phase to the final-stage soaking tank, enabling the liquid phase to enter an extraction liquid evaporation recovery system for evaporation to obtain palm kernel crude oil and fresh solvent, and returning the fresh solvent to the first-stage soaking tank for cyclic extraction.

10. The palm kernel direct leaching process of claim 9, wherein: in the extraction process, a conveying chain drives a scraper to descend along a tunnel above a certain level of baffle plate, palm kernel embryo sheets or wet meal are pushed downwards to be immersed into a current level soaking tank, the scraper bypasses a lower shaft of the current level and ascends along the tunnel below the baffle plate, the wet meal is fished out, ascends along an inclined bottom plate of the current level soaking tank and is drained, and then the wet meal falls to the upper part of a next level of baffle plate from the upper end of the inclined bottom plate or after turning over the upper shaft of the current level;

the liquid level descends from the first stage soaking tank to the back echelon, under the action of the inter-stage liquid level difference, the high-level extract liquid at the low concentration side penetrates through the filter grid plate on the inclined bottom plate and the wet pulp on the filter grid plate, flows into the later stage soaking tank, realizes the preliminary washing of the wet pulp and the replacement of the concentrated extract liquid in the wet pulp, and then the wet pulp goes into the draining section.