Production equipment and method for extracting lignite wax from lignite

Abstract

The production equipment comprises an extractor, the extractor comprises an extraction tank, the extraction tank is divided into a plurality of extraction chambers, and drag chain groups are arranged in the extraction chambers respectively; the drag chain group comprises a first drag chain section, a soaking section and a second drag chain section; an isolation plate is arranged at the bottom of the extraction tank, the isolation plate is arranged below the drag chain group of each extraction chamber, and a through hole penetrating up and down is formed in the isolation plate; the bottom of the extraction tank is provided with a first storage tank and a second storage tank, the first storage tank and the second storage tank are arranged below the isolation plate, the first drag chain section is correspondingly provided with a first spraying device, and the first storage tank is correspondingly arranged below the first drag chain section; the second drag chain section is correspondingly provided with a second spraying device, the second spraying device is used for being communicated with the solvent inlet, the second storage tank is arranged below the second drag chain section, and the soaking section is soaked in the second storage tank; countercurrent contact between the extraction agent and lignite particles is achieved, and lignite wax in the lignite particles is fully extracted.

Description

Technical Field

[0001] This invention belongs to the field of lignite wax production technology, and particularly relates to a production equipment and method for extracting lignite wax from lignite. Background Technology

[0002] Lignite wax has a wide range of applications. In the daily chemical industry, it can be used to produce special cosmetics such as lipstick and hairspray. In the precision casting industry, it is used as a medium- and high-temperature wax mold to help improve the precision and surface finish of castings. In the processing of engineering plastics such as PVC, it acts as a lubricant and release agent to improve processing performance. In the electrical industry, it is used as an insulation material for wires and cables, providing waterproof, moisture-proof and insulating protection.

[0003] The main raw material for lignite wax is lignite. Global lignite resources are abundant, with geological reserves of approximately 4 trillion tons. In the late 19th century, German scientists and engineers (such as Franz Karl Rütgers) pioneered an industrial production process using continuous countercurrent extraction with benzene or toluene.

[0004] Lignite wax is not simply a "substitute," but rather a carrier of unique properties that are difficult for a range of synthetic waxes and most natural waxes to match. Its high melting point (80℃–90℃), high hardness, excellent moisture resistance, insulation and adhesion, as well as good gloss and emulsifying properties, make it an irreplaceable or preferred raw material in specific fields such as precision casting (lost-wax casting), coatings, carbon paper, cable insulation, lubricants, and cosmetics.

[0005] In the extraction process of lignite wax, the drag chain extractor is currently widely used as the core equipment. This extractor operates on a multi-stage solvent spraying principle: the coal seam to be extracted is continuously laid on a circulating drag chain, while the solvent is sprayed onto the coal seam surface in stages by an upper spray system. Under gravity, the solvent permeates and flows downwards through the coal seam, then flows into a solvent collection tank below, completing the first stage of contact extraction. However, this design has inherent limitations—the contact time between the coal and the solvent depends entirely on the time required for the solvent to pass through the coal seam under gravity. Due to the limited thickness of the coal seam and the relatively high solvent flow rate, the actual contact time between the two during each extraction stage is short, resulting in insufficient solvent extraction and low overall extraction efficiency. Therefore, extending the dynamic contact time between the coal and the solvent has become a key area for improvement in enhancing the extraction efficiency of lignite wax. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a production equipment and method for extracting lignite wax from lignite, so as to solve the technical problems of short contact time between solvent and coal seam and low overall extraction efficiency in the prior art.

[0007] To achieve the above objectives, the technical solution adopted by the production equipment for extracting lignite wax from lignite according to the present invention is as follows: A production equipment for extracting lignite wax from lignite, comprising: The extractor includes a feed inlet, a discharge outlet, a liquid outlet, and a solvent inlet. The feed inlet is used for lignite particles to enter the extractor for extraction. The extracted lignite residue is discharged from the discharge outlet, and the extract is discharged from the liquid outlet. A solvent remover is used to connect to the outlet of the extractor to dry and remove solvent from the extracted lignite slag. The solid-liquid separator includes an extractant inlet, a filter residue outlet, and a filtrate outlet. The extractant inlet is connected to the extractor's outlet. The separated coal powder is discharged from the filter residue outlet, and the filtrate is discharged from the filtrate outlet. An evaporator is used to connect to the filtrate outlet of a solid-liquid separator to increase the concentration of lignite wax and resin in the filtrate. A crystallizer, connected to an evaporator, is used to crystallize and precipitate lignite wax from the filtrate; A centrifuge, connected to a crystallizer, is used to separate the crystallized lignite wax from the resin solvent mixture; An evaporator is used to connect to a centrifuge to evaporate the solvent in a resin solvent mixture to obtain concentrated resin. The extractor includes an extraction tank, with the extension direction of the extraction tank defined as the front-to-back direction. Several partitions are fixed at intervals along the front-to-back direction in the extraction tank, and the partitions divide the extraction tank into several extraction chambers. Each extraction chamber is equipped with a drag chain assembly for dragging lignite. The cable chain assembly includes a first cable chain section, an immersion section, and a second cable chain section; the first cable chain section is connected to the feed inlet of the extractor, and the second cable chain section is connected to the discharge outlet of the extractor. The bottom of the extraction tank is equipped with a partition, which is located below the cable chain assembly of each extraction chamber. The partition has through holes running vertically through it. The bottom of the extraction tank is provided with a first storage tank and a second storage tank, which are located below the partition. The first drag chain segment is correspondingly provided with a first spray device, and the first storage tank is correspondingly located below the first drag chain segment, so as to collect the solvent sprayed by the first spray device and the extract after lignite extraction in the first drag chain segment. The second drag chain section is equipped with a second spraying device, which is used to communicate with the solvent inlet. The second storage tank is located below the second drag chain section to collect the extract after the second spraying device sprays the solvent and the lignite extract of the second drag chain section. The soaking section is soaked in the second storage tank, and the surface of the extract in the second storage tank is below the upper surface of the soaking section. The first spraying device is connected to the second storage tank, and the liquid outlet is connected to the first storage tank.

[0008] Beneficial Effects: The present invention provides a production equipment for extracting lignite wax from lignite, wherein the extractor includes an extraction tank, the interior of which is divided into multiple independent extraction chambers by several fixed partitions. Each extraction chamber is equipped with a cable chain assembly for dragging lignite particles. This cable chain assembly is sequentially divided into a first cable chain section, an immersion section, and a second cable chain section. The first cable chain section is equipped with a first spray device, the second cable chain section is equipped with a second spray device, and the immersion section is submerged in a second storage tank. During the extraction process, fresh extractant first enters the second spray device to spray and extract the lignite particles on the second cable chain section. At this time, soluble components (such as lignite wax) in the lignite particles are dissolved by the extractant, and the resulting extract is collected in the second storage tank. The extract in the second storage tank is not directly discharged but is used to soak the immersion section cable chain in the chamber. Since the lignite particles in the soaking section still contain a certain amount of wax, the extractant undergoes further contact extraction with them, further increasing the solute concentration. After the soaking section, the extractant in the second storage tank is pumped to the first spraying device. This device sprays and extracts the lignite particles on the first cable chain section. At this point, the lignite particles on the first cable chain section have the highest wax content, while the extractant used for spraying already contains a certain concentration of wax, but there is still a concentration gradient compared to the first cable chain section, thus continuing to effectively dissolve the lignite wax. The extractant flowing out of the first cable chain section after spraying has reached its highest wax concentration and is collected in the first storage tank as a raw material for subsequent concentration and purification. Through the above process, countercurrent contact between the extractant and the lignite particles is achieved: the fresh extractant preferentially contacts the lignite particles with lower wax content (close to the extraction endpoint), while the extractant with higher wax concentration contacts the fresh lignite particles with the highest wax content. It significantly improves the utilization efficiency of the extractant, while ensuring that the lignite wax in the lignite particles is fully extracted. Moreover, the simultaneous extraction in multiple independent extraction chambers increases the extraction efficiency of lignite wax.

[0009] Furthermore, the extraction tank includes a first extraction tank and a second extraction tank arranged at left and right intervals, a discharge bin is provided between the first extraction tank and the second extraction tank, a conveying structure is provided in the discharge bin, and the discharge port is connected to the discharge bin. The lignite slag extracted from the first and second extraction tanks is discharged into the discharge hopper and then discharged from the outlet via a conveying structure.

[0010] Beneficial effects: With the above structure, the first extraction tank and the second extraction tank share the same discharge bin. On the one hand, this significantly improves the space utilization rate inside the extractor, making the equipment layout more compact and reducing manufacturing and installation costs. On the other hand, the lignite slag discharged from the two extraction tanks is discharged through the conveying structure via a single discharge path, which simplifies the discharge system, effectively avoids the risk of uneven distribution or blockage, and reduces leakage points, making maintenance and subsequent process connections easier.

[0011] Furthermore, the cable chain assembly includes a connecting segment that connects the first cable chain segment and the second cable chain segment, wherein the first cable chain segment, the soaking segment, the second cable chain segment, and the connecting segment are connected end to end to form a closed loop.

[0012] Beneficial effects: The cable chain assembly consists of interconnected segments forming a closed loop, enabling continuous cyclic movement of the cable chain. Lignite particles are automatically and sequentially processed through the first spray extraction, soaking extraction, and second spray extraction processes under the cable chain's drive, without intermediate loading / unloading or interruptions, ensuring the continuity and stability of the extraction process.

[0013] Furthermore, the cross-section of the extraction tank is an inverted trapezoid, and the cable chain assembly is also arranged in an inverted trapezoidal shape. The first drag chain segment in the first extraction tank is an inclined segment that slopes downwards and from left to right, the soaking segment in the first extraction tank is horizontal, and the second drag chain segment in the first extraction tank is an inclined segment that slopes downwards and from right to left; the first drag chain segment in the second extraction tank is an inclined segment that slopes downwards and from right to left, the soaking segment in the second extraction tank is horizontal, and the second drag chain segment in the second extraction tank is an inclined segment that slopes downwards and from right to left.

[0014] Beneficial effects: Setting the first and second cable chain sections at an angle and the soaking section horizontally not only increases the length of the cable chain in the extraction chamber, thereby extending the extraction time of the lignite particles on the cable chain, but also makes the soaking section the bottom of the cable chain assembly, providing conditions for the lignite particles on the soaking section to be soaked in the extractant in the second storage tank, ensuring that the lignite wax in the lignite particles is fully extracted.

[0015] Furthermore, the solvent inlet is connected to the second spray device in the first extraction tank and the second spray device in the second extraction tank, respectively.

[0016] Beneficial effects: It facilitates the simultaneous supply of fresh solvent to the second spray device in the first extraction tank and the second spray device in the second extraction tank, and the structure is simple.

[0017] Furthermore, the first spray section in the first extraction tank is inclined from top to bottom and from left to right, and the second spray section in the first extraction tank is inclined from top to bottom and from right to left; the first spray section in the second extraction tank is inclined from top to bottom and from right to left, and the second spray section in the second extraction tank is inclined from top to bottom and from left to right.

[0018] Beneficial Effects: With the above structure, the first and second spray sections in the first and second extraction tanks are respectively arranged along the inclined direction of the corresponding drag chain sections; that is, the first spray section is inclined in the same direction as the first drag chain section, and the second spray section is inclined in the same direction as the second drag chain section. This design ensures that the spray direction is consistent with the movement direction of the lignite particles, guaranteeing that the solvent can be directly and uniformly sprayed onto the lignite particles in the drag chain section, improving the solvent adhesion efficiency and penetration depth. Simultaneously, the unidirectional inclination eliminates spray dead zones, allowing all lignite particles in the entire drag chain section to achieve sufficient contact, significantly improving extraction uniformity. Furthermore, the symmetrical arrangement of the spray sections in the two extraction tanks optimizes the internal space of the equipment and simplifies pipeline connections and support structures.

[0019] A method for extracting lignite wax from lignite includes the following steps: S1 – Crushing and Screening: Crushing and screening lignite; S2 - Drying: Drying the lignite; S3 - Continuous Extraction: Lignite particles are conveyed to the extractor, organic solvent is added from the solvent inlet, the organic solvent is used for countercurrent extraction in the extraction chamber, the extracted lignite residue is discharged from the outlet, and the extract is discharged from the liquid outlet. S4 ~ Coal Slag Desolventizing: The extracted lignite slag enters the desolventizing unit for drying and desolventizing, so as to evaporate and remove the solvent from the lignite slag; S5 - Solid-liquid separation: The extract enters the solid-liquid separator, filters the coal powder in the extract and discharges it from the filter residue outlet, and the filtrate is discharged from the filtrate outlet. S6 ~ Wax Concentration: The filtered extract is concentrated and crystallized to allow lignite wax to crystallize out of the extract, and the lignite wax is separated from the resin by a centrifuge. S7 ~ Resin Concentration: The resin solvent mixture from which lignite wax has been separated is evaporated to remove the solvent from the resin solvent mixture, thus obtaining concentrated resin.

[0020] Beneficial Effects: The extractor in the lignite wax extraction equipment of the present invention includes an extraction tank with several partitions fixed inside, dividing the extraction tank into multiple independent extraction chambers. Each extraction chamber is equipped with a cable chain assembly for dragging lignite particles. This cable chain assembly is sequentially divided into a first cable chain section, an immersion section, and a second cable chain section. The first cable chain section is equipped with a first spray device, and the second cable chain section is equipped with a second spray device. The immersion section is submerged in a second storage tank. During the extraction process, fresh extractant first enters the second spray device to spray and extract the lignite particles on the second cable chain section. At this time, soluble components (such as lignite wax) in the lignite particles are dissolved by the extractant, and the resulting extract is collected in the second storage tank. The extract in the second storage tank is not directly discharged but is used to soak the cable chain in the immersion section of the chamber. Since the lignite particles on the immersion section still contain a certain amount of wax, the extract undergoes further contact extraction with it, further increasing the solute concentration. After the immersion section, the extract in the second storage tank is pumped to the first spray device. This device performs spray extraction on lignite particles on the first cable carrier section. At this point, the lignite particles on the first cable carrier section have the highest wax content, while the extract used for spraying already contains a certain concentration of wax, but a concentration gradient still exists compared to the first cable carrier section, thus continuing to effectively dissolve the lignite wax. The extract flowing out of the first cable carrier section after spraying, at which point the wax concentration has reached its maximum, is collected in the first storage tank as raw material for subsequent concentration and purification. Through the above process, countercurrent contact between the extractant and the lignite particles is achieved: fresh extractant preferentially contacts lignite particles with lower wax content (close to the extraction endpoint), while extract with higher wax concentration contacts fresh lignite particles with the highest wax content. This significantly improves the utilization efficiency of the extractant, while ensuring that the lignite wax in the lignite particles is fully extracted. Moreover, simultaneous extraction in multiple independent extraction chambers increases the extraction efficiency of lignite wax.

[0021] Furthermore, in S7, the solvent evaporated from the resin solvent mixture is condensed and recovered, then enters the water separation system to separate the solvent and is stored in the solvent storage tank.

[0022] Beneficial Effects: In the S7 process, the solvent evaporated from the resin-solvent mixture is condensed and recovered, then enters a water separation system to separate moisture before being stored in a solvent storage tank for recycling. This design achieves closed-loop solvent recycling: on the one hand, it significantly reduces the consumption of fresh solvent, lowering raw material procurement and transportation costs; on the other hand, it avoids material loss and environmental pollution caused by direct emission of solvent-containing vapors, meeting clean production requirements. Simultaneously, the water separation system effectively removes moisture entrained in the recovered solvent, ensuring solvent purity and preventing moisture from adversely affecting subsequent extraction processes, thereby maintaining stable lignite wax extraction efficiency and product quality. Attached Figure Description

[0023] Figure 1 This is a cross-sectional schematic diagram of the extractor in a production equipment for extracting lignite wax from lignite according to the present invention; Figure 2 yes Figure 1 A schematic diagram of the structure of the first extraction tank, the discharge bin, and the second extraction tank of the intermediate extractor; Figure 3 yes Figure 1 A schematic diagram of the extraction chamber formed by the separator and partition plates in the middle extractor; Figure 4 This is a schematic diagram of the corresponding cable chain assembly in the extraction chamber of the first extraction tank; Figure 5 This is a structural diagram of the chain and slide of the cable chain assembly.

[0024] Reference numerals: 1-First extraction tank; 2-Second extraction tank; 3-Discharge bin; 4-Inlet; 5-Solvent inlet; 6-Outlet; 7-Isolation plate; 8-Drag chain assembly; 9-First spray section; 10-Second spray section; 11-First storage tank; 12-Second storage tank; 13-Conveyor belt; 14-Baffle plate; 15-Extraction chamber; 17-Through hole; 18-First drag chain section; 19-Soaking section; 20-Second drag chain section; 21-Connecting section; 22-U-shaped section; 23-Connecting rod; 24-Drag plate. Detailed Implementation

[0025] The following is a detailed description of a production equipment and method for extracting lignite wax from lignite according to the present invention, with reference to the accompanying drawings and specific embodiments: A production equipment for extracting lignite wax from lignite includes an extractor, a solvent remover, a solid-liquid separator, an evaporator, a crystallizer, a centrifuge, and an evaporator concentrator. The extractor includes an inlet 4, an outlet 6, a liquid outlet 6, and a solvent inlet 5. The inlet 4 is used for lignite particles to enter the extractor for extraction. The extracted lignite residue is discharged from the outlet 6, and the extract is discharged from the liquid outlet 6. The desolventizer is connected to the outlet of the extractor to dry and desolventize the extracted lignite residue. The solid-liquid separator includes an extract inlet, a filter residue outlet, and a filter liquid outlet. The extract inlet is connected to the liquid outlet 6 of the extractor. The separated coal powder is discharged from the filter residue outlet, and the filter liquid is discharged from the filter liquid outlet. The evaporator is connected to the filter liquid outlet of the solid-liquid separator to increase the concentration of lignite wax and resin in the filter liquid. The crystallizer is connected to the evaporator to crystallize the lignite wax in the filter liquid, making the extract liquid a mixture of lignite wax crystals and resin solvent. The centrifuge is connected to the crystallizer to separate the crystallized lignite wax from the resin solvent mixture. The evaporator concentrator is connected to the centrifuge to evaporate the solvent in the resin solvent mixture to obtain concentrated resin.

[0026] The extractor includes an extraction tank, defined as extending in a front-to-back direction. The extraction tank comprises a first extraction tank 1 and a second extraction tank 2 spaced apart on either side. A discharge chamber 3 is located between the first extraction tank 1 and the second extraction tank 2. A conveying structure is installed in the discharge chamber 3, and the discharge port is connected to the discharge chamber 3. In this embodiment, the conveying structure is a conveyor belt 13 that moves materials from front to back, with the end of the conveyor belt 13 connected to the discharge port. The discharge port is located on the rear side wall of the extractor.

[0027] Several partitions 14 are fixed at intervals along the front-to-back direction in the extraction tank, dividing the extraction tank into several extraction chambers 15. Each extraction chamber 15 is equipped with a drag chain assembly 8 for dragging lignite. The drag chain assembly 8 includes a first drag chain segment 18, a soaking segment, a second drag chain segment, and a connecting segment 21 connecting the first drag chain segment 18 and the second drag chain segment. The first drag chain segment, soaking segment, second drag chain segment, and connecting segment 21 are connected end-to-end to form a closed loop. The first drag chain segment 18 is connected to the feed inlet 4 of the extractor, and the second drag chain segment is connected to the discharge outlet of the extractor. In this embodiment, the top of the second drag chain segment is connected to the discharge bin 3. The lignite residue extracted by the first extraction tank 1 and the second extraction tank 2 is discharged into the discharge bin 3 and discharged from the discharge outlet through the conveying structure. In this embodiment, feed inlets 4 are respectively opened on the left and right sides of the extractor, and the feed inlets 4 are respectively set to correspond to the extraction chambers 15 of the first extraction tank 1 and the second extraction tank 2.

[0028] The cross-section of the extraction tank is an inverted trapezoid, wider at the top and narrower at the bottom, and the cable chain assembly 8 is also an inverted trapezoid, wider at the top and narrower at the bottom. The first cable chain segment 18 in the first extraction tank 1 is an inclined segment that slopes downwards and from left to right. The soaking segment 19 in the first extraction tank 1 is horizontally positioned. The second cable chain segment 20 in the first extraction tank 1 is an inclined segment that slopes downwards and from right to left. The cable chain assembly 8 in the first extraction tank rotates counterclockwise. The first cable chain segment in the second extraction tank 2 is an inclined segment that slopes downwards and from right to left. The soaking segment in the second extraction tank 2 is horizontally positioned. The second cable chain segment in the second extraction tank 2 is an inclined segment that slopes downwards and from right to left. The cable chain assembly in the second extraction tank rotates clockwise.

[0029] The cable chain assembly 8 includes two parallel chains spaced apart from each other. Each chain includes several hinged components, each component including a U-shaped segment 22 and a connecting rod 23 fixedly connected to the U-shaped segment 22. The connecting rod 23 extends into the U-shaped segment 22 of the adjacent component, and the connecting rod 23 and the U-shaped segment 22 are hingedly connected. The cable chain assembly 8 also includes a sprocket for chain engagement to achieve reversing. A drag plate 24 is fixedly provided between the two chains of the same cable chain assembly 8.

[0030] Solvent inlet 5 is located at the top of the extractor and is connected to the second spray device in the first extraction tank 1 and the second spray device in the second extraction tank 2, respectively, so as to deliver fresh solvent to the second spray device in the first extraction tank 1 and the second spray device in the first extraction tank 2 through solvent inlet 5.

[0031] The first spray section 9 in the first extraction tank 1 is inclined from top to bottom and from left to right, and the second spray section 10 in the first extraction tank 1 is inclined from top to bottom and from right to left. In this embodiment, multiple first spray sections 9 and second spray sections 10 in the first extraction tank 1 are spaced apart in the front-to-back direction. One end of the first spray section 9 is connected to the first conveying pipe, which is connected to the second storage tank 12. A conveying pump is installed on the section of the first conveying pipe located in the second storage tank 12 to pump the extract in the second storage tank 12 to the first spray section 9. The second spray section 10 is connected to the solvent inlet 5. The other end of the first spray section 9 is fixedly connected to the first fixed pipe. The first spray section in the second extraction tank 2 is inclined from top to bottom and from right to left, and the second spray section in the second extraction tank 2 is inclined from top to bottom and from left to right. In this embodiment, multiple first and second spray sections are spaced apart in the front-to-back direction in the second extraction tank 2. One end of each first spray section is connected to a second conveying pipe, which is connected to a second storage tank 12. A conveying pump is installed on the section of the second conveying pipe in the second storage tank 12 to pump the extractant from the second storage tank 12 to the first spray section. The other end of each first spray section is fixedly connected to a second fixed pipe. Both the first and second spray sections are equipped with multiple nozzles. The second spray section in the second extraction tank 2 is connected to the solvent inlet 5.

[0032] The first spray section and the second spray section in the first extraction tank 1 and the second extraction tank 2 are respectively set along the inclined direction of the corresponding drag chain section, that is, the first spray section is inclined in the same direction as the first drag chain section, and the second spray section is inclined in the same direction as the second drag chain section. This design ensures that the spray direction is consistent with the movement direction of the lignite particles, ensuring that the solvent can be sprayed directly and evenly onto the lignite particles in the drag chain section, thereby improving the solvent adhesion efficiency and penetration depth.

[0033] The bottom of the extraction tank is provided with a partition plate 7, which is located below the drag chain assembly 8 of each extraction chamber 15. The partition plate 7 has through holes 17 that run vertically through it, and the diameter of the through holes 17 is smaller than the particle size of the lignite. The bottom of the extraction tank is provided with a first storage tank 11 and a second storage tank 12. The partition plate 7 is located below the partition plate 14, and the partition plate 14 in the extraction tank is vertically fixed on the partition plate 7.

[0034] A first spray device is correspondingly provided on the first cable chain segment, and a first storage tank 11 is correspondingly provided below the first cable chain segment to collect the solvent sprayed by the first spray device and the extract after lignite extraction in the first cable chain segment. A second spray device is correspondingly provided on the second cable chain segment, and the second spray device is used to communicate with the solvent inlet 5. A second storage tank 12 is provided below the second cable chain segment to collect the solvent sprayed by the second spray device and the extract after lignite extraction in the second cable chain segment. The soaking section is immersed in the second storage tank 12, and the level of the extract in the second storage tank 12 is below the upper surface of the soaking section to prevent lignite particles from being extracted and floating between the chain plates of adjacent cable chain groups 8, which would affect the extraction. The first spray device and the second storage tank 12 are connected, and the liquid outlet 6 is connected to the first storage tank 11. In this embodiment, the liquid outlet 6 is opened at the bottom of the extractor, and the liquid outlet 6 of the first extraction tank 1 and the liquid outlet 6 of the second extraction tank 2 are connected to the liquid outlet pipe.

[0035] A method for extracting lignite wax from lignite includes the following steps: S1 - Crushing and Screening: The lignite is crushed and screened. The lignite mined from the mine is transported to the workshop for crushing and screening. The size of the screened lignite particles is 3mm-15mm. Coal powder smaller than 3mm is then granulated. S2 - Drying: The lignite particles are dried to a moisture content of about 20%, which improves the efficiency of lignite wax extraction. S3 - Continuous extraction: Lignite particles are conveyed to the extractor, organic solvent is added from solvent inlet 5, and organic solvent is used for countercurrent extraction in extraction chamber 15. The extracted lignite residue is discharged from the outlet, and the extract is discharged from the liquid outlet 6. During the extraction process, fresh extractant first enters the second spray device to extract lignite particles on the second cable chain section. At this time, soluble components (such as lignite wax) in the lignite particles are dissolved by the extractant, and the resulting extract is collected in the second storage tank 12. The extract in the second storage tank 12 is not directly discharged but is used to soak the cable chain in the soaking section of the chamber. Since the lignite particles in the soaking section still contain a certain amount of wax, the extract undergoes further contact extraction with it, further increasing the solute concentration. After the soaking section, the extract in the second storage tank 12 is pumped to the first spray device. This device performs spray extraction on the lignite particles on the first cable chain section. At this point, the lignite particles on the first drag chain section have the highest wax content, while the extract used for spraying already contains a certain concentration of wax, but there is still a concentration gradient compared to the first drag chain section, thus continuing to effectively dissolve the lignite wax; the extract flowing out of the first drag chain section after spraying has reached its highest wax concentration and is collected in the first storage tank 11 as a raw material for subsequent concentration and purification; in this embodiment, the organic solvent is butyl acetate; the extraction temperature is 80 ℃, the extractor operates at a speed of 4 hours per revolution of the drag chain group 8, and the organic solvent is subjected to countercurrent extraction; S4 – Coal Slag Desolventizing: The extracted lignite slag enters a desolventizing unit for drying and desolventizing to evaporate and remove the solvent from the lignite slag. In this embodiment, a horizontal ribbon dryer is selected as the desolventizing unit. The horizontal ribbon dryer is divided into two stages (low-temperature desolventizing cylinders A and B), using steam heating. The jacket steam pressure is 1.0 MPa, the drying time is 20 min, the first stage temperature is 135℃, and the second stage temperature is 135℃-140℃. The residual solvent in the dewaxed coal is less than 500 ppm. In this embodiment, the structure and desolventizing principle of the horizontal ribbon dryer are existing technologies and will not be described in detail here. S5 - Solid-liquid separation: The extract rich in lignite wax contains fine coal powder. The extract enters the solid-liquid separator, where the coal powder in the extract is filtered out and discharged from the filter residue outlet. The filtrate is discharged from the filtrate outlet, ensuring that the finished lignite wax and by-product resin are free of ash powder, thus improving product quality. In this embodiment, the structure and separation principle of the solid-liquid separator are existing technologies and will not be described in detail here. S6 – Wax Concentration: The filtered extract is concentrated and crystallized to precipitate lignite wax from the extract. A centrifuge is then used to separate the lignite wax from the resin. First, an evaporator is used to increase the concentration of lignite wax and resin from 7% to 10%, significantly reducing the number of crystallizers and the difficulty of separation. Then, using a crystallizer, the cooling curve and cooling time are controlled for 36 hours, allowing the lignite wax to crystallize at a low temperature of 10°C, achieving separation of the lignite wax and resin and ensuring that the resin content in the lignite wax is below 5%. Next, a centrifuge is used to separate the frozen mixed solvent solution, ensuring that the solvent content in the lignite wax is less than 35%. Furthermore, rinsing with fresh frozen solvent further ensures that the resin content in the lignite wax is below 5%. In this embodiment, the structure and operating principle of the evaporator, crystallizer, and centrifuge are existing technologies and will not be described in detail here.

[0036] S7 – Resin Concentration: The resin-solvent mixture from which lignite wax has been separated is evaporated using an evaporator to remove 99% of the solvent. Then, it is concentrated under normal pressure to obtain concentrated resin. Finally, it is concentrated under negative pressure (-0.095 MPa) at 145 °C for 2 hours to ensure the solvent content is less than 50 ppm. The resin is then sliced ​​into flakes using a slicer to ensure the quality of the by-product resin. In this embodiment, the structure and operating principle of the evaporator are existing technologies and will not be described in detail here.

[0037] In S7, the solvent evaporated from the resin-solvent mixture is condensed and recovered, then enters the water separation system to separate the solvent and is stored in the solvent storage tank. Fresh solvent in the solvent storage tank is heated to 80°C through a solvent heat exchanger before entering the extractor, thus achieving solvent recycling.

[0038] In the above embodiments, the extraction tank includes a first extraction tank and a second extraction tank arranged at an interval from left to right, and a discharge bin is provided between the first extraction tank and the second extraction tank; in other embodiments, the extraction tank may also include only the first extraction tank or the second extraction tank, in which case the discharge bin is located on one side of the first extraction tank and the second extraction tank.

[0039] In the above embodiments, the cable chain assembly includes a connecting section that connects the first cable chain segment and the second cable chain segment. The first cable chain segment, the soaking section, the second cable chain segment, and the connecting section are connected end to end to form a closed loop. In other embodiments, the connecting section may not be included. In this case, the first cable chain segment is an independent conveyor chain, the soaking section is an independent conveyor chain, and the second cable chain segment is an independent conveyor chain. Furthermore, the first cable chain segment conveys lignite particles to the soaking section, and the soaking section conveys lignite particles to the second cable chain segment.

[0040] In the above embodiments, the solvent inlet is connected to the second spray device in the first extraction tank and the second spray device in the second extraction tank, respectively. In other embodiments, the second spray device in the first extraction tank and the second spray device in the second extraction tank can be connected to the corresponding solvent inlet, respectively.

[0041] In the above embodiments, the first spray section in the first extraction tank is inclined from top to bottom and from left to right, and the second spray section in the first extraction tank is inclined from top to bottom and from right to left; the first spray section in the second extraction tank is inclined from top to bottom and from right to left, and the second spray section in the second extraction tank is inclined from top to bottom and from left to right; in other embodiments, the first spray section and the second spray section may also be horizontally arranged.

Claims

1. A production equipment for extracting lignite wax from lignite, characterized in that, include The extractor includes a feed inlet, a discharge outlet, a liquid outlet, and a solvent inlet. The feed inlet is used for lignite particles to enter the extractor for extraction. The extracted lignite residue is discharged from the discharge outlet, and the extract is discharged from the liquid outlet. A solvent remover is used to connect to the outlet of the extractor to dry and remove solvent from the extracted lignite slag. The solid-liquid separator includes an extractant inlet, a filter residue outlet, and a filtrate outlet. The extractant inlet is connected to the extractor's outlet. The separated coal powder is discharged from the filter residue outlet, and the filtrate is discharged from the filtrate outlet. An evaporator is used to connect to the filtrate outlet of a solid-liquid separator to increase the concentration of lignite wax and resin in the filtrate. A crystallizer, connected to an evaporator, is used to crystallize and precipitate lignite wax from the filtrate; A centrifuge, connected to a crystallizer, is used to separate the crystallized lignite wax from the resin solvent mixture; An evaporator is used to connect to a centrifuge to evaporate the solvent in a resin solvent mixture to obtain concentrated resin. The extractor includes an extraction tank, with the extension direction of the extraction tank defined as the front-to-back direction. Several partitions are fixed at intervals along the front-to-back direction in the extraction tank, and the partitions divide the extraction tank into several extraction chambers. Each extraction chamber is equipped with a drag chain assembly for dragging lignite. The cable chain assembly includes a first cable chain section, an immersion section, and a second cable chain section; the first cable chain section is connected to the feed inlet of the extractor, and the second cable chain section is connected to the discharge outlet of the extractor. The bottom of the extraction tank is equipped with a partition plate, which is located below the cable chain assembly of each extraction chamber. The partition plate has through holes running vertically through it. The bottom of the extraction tank is provided with a first storage tank and a second storage tank, which are located below the isolation plate. The first drag chain segment is correspondingly provided with a first spray device, and the first storage tank is correspondingly located below the first drag chain segment to collect the solvent sprayed by the first spray device and the extract after lignite extraction from the first drag chain segment. The second drag chain section is equipped with a second spraying device, which is used to communicate with the solvent inlet. The second storage tank is located below the second drag chain section to collect the extract after the second spraying device sprays the solvent and the lignite extract of the second drag chain section. The soaking section is soaked in the second storage tank, and the surface of the extract in the second storage tank is below the upper surface of the soaking section. The first spraying device is connected to the second storage tank, and the liquid outlet is connected to the first storage tank.

2. The production equipment for extracting lignite wax from lignite according to claim 1, characterized in that, The extraction tank includes a first extraction tank and a second extraction tank arranged at left and right intervals. A discharge hopper is provided between the first extraction tank and the second extraction tank. A conveying structure is provided in the discharge hopper. The discharge port is connected to the discharge hopper. The lignite slag extracted from the first and second extraction tanks is discharged into the discharge hopper and then discharged from the outlet via a conveying structure.

3. The production equipment for extracting lignite wax from lignite according to claim 2, characterized in that, The cable chain assembly includes a connecting section that connects the first cable chain segment and the second cable chain segment. The first cable chain segment, the soaking section, the second cable chain segment, and the connecting section are connected end to end to form a closed loop.

4. The production equipment for extracting lignite wax from lignite according to claim 3, characterized in that, The cross-section of the extraction tank is an inverted trapezoid, and the cable chain assembly is also arranged in an inverted trapezoidal shape. The first drag chain segment in the first extraction tank is an inclined segment that slopes downwards and from left to right, the soaking segment in the first extraction tank is horizontal, and the second drag chain segment in the first extraction tank is an inclined segment that slopes downwards and from right to left; the first drag chain segment in the second extraction tank is an inclined segment that slopes downwards and from right to left, the soaking segment in the second extraction tank is horizontal, and the second drag chain segment in the second extraction tank is an inclined segment that slopes downwards and from right to left.

5. The production equipment for extracting lignite wax from lignite according to claim 4, characterized in that, The solvent inlet is connected to the second spray device in the first extraction tank and the second spray device in the second extraction tank.

6. The production equipment for extracting lignite wax from lignite according to claim 5, characterized in that, The first spray section in the first extraction tank is inclined from top to bottom and from left to right, and the second spray section in the first extraction tank is inclined from top to bottom and from right to left; the first spray section in the second extraction tank is inclined from top to bottom and from right to left, and the second spray section in the second extraction tank is inclined from top to bottom and from left to right.

7. A production method for a production equipment for extracting lignite wax from lignite according to any one of claims 1-6, characterized in that, Includes the following steps: S1 – Crushing and Screening: Crushing and screening lignite; S2 - Drying: Drying the lignite; S3 - Continuous Extraction: Lignite particles are conveyed to the extractor, organic solvent is added from the solvent inlet, the organic solvent is used for countercurrent extraction in the extraction chamber, the extracted lignite residue is discharged from the outlet, and the extract is discharged from the liquid outlet. S4 ~ Coal Slag Desolventizing: The extracted lignite slag enters the desolventizing unit for drying and desolventizing, so as to evaporate and remove the solvent from the lignite slag; S5 - Solid-liquid separation: The extract enters the solid-liquid separator, filters the coal powder in the extract and discharges it from the filter residue outlet, and the filtrate is discharged from the filtrate outlet. S6 ~ Wax Concentration: The filtered extract is concentrated and crystallized to allow lignite wax to crystallize out of the extract, and the lignite wax is separated from the resin by a centrifuge. S7 ~ Resin Concentration: The resin solvent mixture from which lignite wax has been separated is evaporated to remove the solvent from the resin solvent mixture, thus obtaining concentrated resin.

8. A method for extracting lignite wax from lignite according to claim 7, characterized in that, In S7, the solvent evaporated from the resin solvent mixture is condensed and recovered, then enters the water separation system to separate the solvent and is stored in the solvent storage tank.

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