Coal slime freeze thawing and residue removing device and method

Abstract

The invention discloses a coal slime freezing and thawing residue removing device and method. The device comprises a hollow tooth roller system, a freezing circulating system and a control system. The hollow tooth roller system comprises a rack, two symmetrical tooth rollers, a bearing seat, a hollow shaft and a high-frequency coil, the two tooth rollers are meshed with each other, a cavity is formed in each tooth roller, the hollow shaft is inserted into the bearing seat and the axis of the tooth roller so as to realize rotation of the tooth roller, the two ends of the hollow shaft are open, and the high-frequency coil is arranged close to the tooth roller; the refrigeration circulation system comprises refrigerant, a rotary joint, a liquid supply pipe and a refrigerator, one end of the liquid supply pipe is connected with the refrigerator, the other end of the liquid supply pipe is connected with the rotary joint, the rotary joint is inserted into the hollow shaft and communicated with the cavity, and the refrigerant flows in the refrigeration circulation system and the cavity; by means of the freezing and crushing technology, the problems of sticking, blocking, loss, pollution and the like in the coal slime sample preparation process are effectively solved, the sample preparation representativeness and accuracy are remarkably improved, and the coal slime sample preparation device has the advantages of being reasonable in operation cost, safe, easy and convenient to operate and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coal slime sampling, in particular to a coal slime freeze-thaw residual cleaning device and method. BACKGROUND

[0002] With the development of coal blending combustion technology, more and more power plants blend coal slime to improve economic benefits. Coal slime sampling is a key link in coal quality detection, and its accuracy directly affects trade settlement and production process adjustment. As a byproduct of coal washing and processing, coal slime has the characteristics of high moisture, high viscosity and high plasticity, and its sampling process faces great challenges.

[0003] The main reasons why coal slime is difficult to break are as follows: 1. Complexity of water form: the water content in coal slime is not only high, but also has complex form. Surface adsorbed water produces viscosity through intermolecular force; capillary water remains in micropores through surface tension; combined water forms hydrated ions with clay minerals. These different forms of water work together to make coal slime exhibit strong viscosity. 2. Strong inter-particle force: there are various forces between coal slime particles, including liquid bridge force, van der Waals force, electrostatic attraction and mechanical interlocking force, among which the liquid bridge force is the most important. For fine particles, this force is enough to cause strong agglomeration and easily form dough. 3. Special properties of clay minerals: the clay minerals such as montmorillonite contained in coal slime have a layered structure, and can adsorb a large number of water molecules between the layers, causing lattice expansion, further enhancing the viscosity and plasticity of coal slime.

[0004] This also leads to the following problems in the sampling process: 1. Sample representativeness is damaged: in the traditional breaking process, high-viscosity coal slime adheres to the surface of the breaking tooth roller, causing sample loss rate of 3-5%, seriously affecting the representativeness of sampling and the accuracy of analysis. Adhesion causes separation of sample components, and fine particles and high-ash materials are more likely to adhere, causing deviation of the final sample from the original sample. 2. Low cleaning efficiency: mechanical cleaning methods have dead angles, and the residual coal between the teeth is not completely cleaned, requiring frequent manual cleaning during shutdown, resulting in low sampling efficiency. Each cleaning requires shutdown for tens of minutes, seriously affecting the continuity of sampling. 3. Difficulty in maintaining moisture: mechanical friction generates heat, causing coal slime moisture loss (1.5-3.0%), changing the original characteristics of the sample and affecting the accuracy of moisture, volatile matter and other indicators. 4. Severe equipment wear: hard contact cleaning of the scraper and tooth roller causes rapid equipment wear, high maintenance cost and short service life. The average service life of the scraper is short and needs to be replaced frequently. 5. High energy consumption: mechanical cleaning requires additional power consumption, and the adhesion increases the breaking resistance and increases the load on the motor, resulting in more than 10% increase in comprehensive energy consumption.

[0005] A new double-toothed roll coal slime crusher is disclosed in Chinese Patent No. CN118179665A. The technology uses mechanical cleaning to solve the problem of residual coal between the teeth. Its technical features include a double-crushing roller structure, a plurality of crushing teeth arranged on the roller surface, a hydraulic-driven scraper system, adjustable scraper position, a spring support rod design, a reciprocating cleaning mechanism driven by a pneumatic cylinder, and the like. The working principle is as follows: the scraper position is adjusted by the hydraulic system, the scraper is inserted into the tooth gap, and the scraper is driven by the pneumatic cylinder to make reciprocating motion to scrape the residual coal between the teeth. The scraper is designed in sections and can be replaced individually according to the wear condition. Although this technology improves the cleaning effect between the teeth to some extent, it still belongs to passive mechanical cleaning and cannot fundamentally solve the problem of coal slime adhesion. At the same time, the structure is complex, the coordination requirement is high, and the reliability is difficult to guarantee. SUMMARY

[0006] The technical problem to be solved by the present application is to overcome the defects of poor sample representativeness, water loss, cross contamination and the like in the prior art, and to provide a coal slime freeze-thaw residual cleaning device and method.

[0007] The technical solution adopted by the present application to solve its technical problem is a coal slime freeze-thaw residual cleaning device and method, which comprises a hollow toothed roller system, a freezing circulation system and a control system.

[0008] The hollow toothed roller system comprises a rack, toothed rollers, bearing seats, hollow shafts and high-frequency coils. The toothed rollers are symmetrically arranged and meshed with each other. The two toothed rollers are installed in parallel in the rack and form a crushing cavity. The toothed rollers have a closed hollow structure and a cavity inside. The bearing seats are installed on both sides of the rack. The hollow shafts are inserted into the shaft centers of the bearing seats and the toothed rollers to realize the rotation of the toothed rollers. The hollow shafts are open at both ends. The high-frequency coils are arranged on the rack and close to the toothed rollers.

[0009] The freezing circulation system comprises cold coal, a rotary joint, a liquid supply pipe and a freezer. The freezer is independently arranged outside the rack. One end of the liquid supply pipe is connected to the freezer, and the other end is connected to the rotary joint. The rotary joint is inserted into the hollow shaft and communicates with the cavity of the toothed roller. The cold coal flows in the rotary joint, the liquid supply pipe, the freezer and the cavity.

[0010] The control system comprises a PLC controller and a temperature sensor. The temperature sensor is used to detect the temperature, and the PLC controller is used for mode switching and switching of the device.

[0011] Further, the material of the toothed roller is high-strength alloy steel with high thermal conductivity.

[0012] Further, the high-frequency coil is arranged at the rack away from the meshing position of the two toothed rollers.

[0013] Further, the rotary joint is provided with two and is inserted into the hollow shaft from both ends respectively, and the rotary joint has a connecting pipe which is communicated with the cavity of the tooth roll.

[0014] Further, the refrigeration cycle system further comprises a liquid return pipe, one of the rotary joints is connected to the liquid supply pipe, and the other rotary joint is connected to the liquid return pipe.

[0015] Further, the liquid return pipe and the liquid supply pipe are provided with stop valves and temperature sensors.

[0016] Further, the refrigerant is calcium chloride brine.

[0017] Further, the application further solves the technical problem, and a coal slime freeze-thaw residual cleaning device is provided.

[0018] S1, crushing and real-time anti-sticking;

[0019] S1.1, the coal slime is normally sent into the double-tooth roll crusher for crushing;

[0020] S1.2, the low-temperature refrigerant is continuously circulated in the hollow tooth roll;

[0021] S1.3, the temperature of the surface of the tooth roll is reduced, so that a thin layer of coal slime which is in contact with the surface of the tooth roll or just adheres to the surface is rapidly cooled below the freezing point;

[0022] S2, finishing and residual cleaning;

[0023] S2.1, the control system automatically switches the valve to stop the refrigerant from being supplied;

[0024] S2.2, the high-frequency coil is started, and the high-frequency coil acts on the tooth roll to instantaneously heat the roll teeth to 5-10℃.

[0025] Further, step S1 further comprises S1.4, the surface moisture of the coal slime is frozen, the adhesion is reduced, and the coal slime is crushed under the action of the two tooth rolls.

[0026] In summary, the application has the following beneficial technical effects:

[0027] The application discards the traditional mechanical scraping idea and proposes a crushing and freezing anti-sticking method and a finishing and self-cleaning heating method. The core is that in the crushing process, the coal slime adhered to the surface of the tooth roll is instantaneously frozen, so that the coal slime loses adhesion and changes from a plastic body to a brittle body, so that it is more easily detached under the subsequent washing and extrusion of the coal slime, and the adhesion is greatly reduced. In the finishing stage after the crushing operation is completed, the tooth roll is supplied with a heating medium, so that the frozen coal slime and the thin ice layer of the roll surface are rapidly melted, so that the coal slime is completely detached by using its weight and the centrifugal force of the roll, and the tooth roll is self-cleaned.

[0028] By the freezing crushing technique, the problems of sticking, loss and pollution in the coal slime sampling are effectively solved, the sampling representativeness and accuracy are significantly improved, and the operation cost is reasonable, the operation is safe and simple, and the device is especially suitable for the sampling treatment of high-moisture coal slime in the coal quality inspection, electric power, metallurgy and other industries. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 Fig. 1 is a schematic diagram of the overall structure of the rack of an embodiment of the coal slime freeze-thaw residual cleaning device;

[0030] Figure 2 Fig. 2 is a front view of the coal slime freeze-thaw residual cleaning device;

[0031] Figure 3 Fig. 3 is a partial structure schematic diagram of the coal slime freeze-thaw residual cleaning device.

[0032] BRIEF DESCRIPTION OF DRAWINGS

[0033] 1, rack; 101, crushing cavity; 2, tooth roller; 201, cavity; 3, bearing seat; 4, hollow shaft; 5, high-frequency coil; 6, belt pulley; 7, liquid supply pipe; 8, rotary joint; 801, connecting pipe; 9, stop valve; 10, liquid return pipe; 11, freezer; 12, control unit; 13, sticky coal residual coal. DETAILED DESCRIPTION

[0034] The application will be further described in detail below with reference to the drawings and embodiments.

[0035] Referring to Figure 1 , the embodiment includes a hollow tooth roller system, a freezing circulation system and a control system, wherein the hollow tooth roller system and the freezing circulation system are connected to each other, and the control system controls the hollow tooth roller system and the freezing circulation system.

[0036] Referring to Figure 2 and Figure 3 , specifically, the hollow tooth roller system is the main body for crushing, which includes a rack, a tooth roller, a bearing seat, a hollow shaft and a high-frequency coil. The rack is the main body for installation. The tooth roller, the bearing seat, the hollow shaft, the high-frequency coil and the belt pulley are all installed on the rack. The tooth roller is provided with two symmetrical tooth rollers which are engaged with each other. The two tooth rollers are located in the content of the rack and form a crushing cavity. The roller body of the tooth roller is a closed hollow structure and is a whole annular structure. An internal cavity is designed in the roller body. The bearing seat is arranged on the outer two sides of the rack and is flush with the tooth roller. The hollow shaft is directly inserted into the bearing shaft center of the bearing seat to realize the connection with the tooth roller. The hollow shaft is hollow in the inside and open at both ends, so that the freezing circulation system can be connected to the cavity of the tooth roller through the hollow shaft. The high-frequency coil is arranged on the rack and close to the tooth roller and is arranged at a position away from the engagement position of the two tooth rollers.

[0037] In addition, the material of the tooth roller is high-strength alloy steel with high thermal conductivity, so as to determine the heat exchange efficiency of the refrigeration cycle system and the tooth roller, and prevent refrigerant corrosion.

[0038] With reference to Figure 2 , the refrigeration cycle system is divided into two parts of refrigeration and pipeline, and specifically includes a cooling coil, a rotary joint, a liquid supply pipe, a liquid return pipe and a refrigerator, the refrigerator is arranged outside the rack independently, the liquid supply pipe and the liquid return pipe are both connected to the refrigerator at one end and connected to the rotary joint at the other end, the rotary joint is inserted into the hollow shaft and communicates with the cavity of the tooth roller, the rotary joint has a connecting pipe which communicates with the cavity of the tooth roller, and the cooling coil flows in the rotary joint, the liquid supply pipe, the refrigerator and the cavity.

[0039] With reference to Figure 2 , specifically, two rotary joints are arranged, one left and one right, which are inserted into the hollow shaft, one rotary joint is connected to the liquid supply pipe, and the other rotary joint is connected to the liquid return pipe, and the other ends of the liquid supply pipe and the liquid return pipe are both connected to the refrigerator, and the liquid supply pipe and the liquid return pipe are both provided with a stop valve. In addition, when the tooth roller rotates, the rotary joint also rotates synchronously with the tooth roller to avoid the pipeline from being knotted with each other or excessively rotating.

[0040] The control system includes a temperature sensor, a PLC controller and a man-machine interface, the temperature sensor is used for detecting temperature, the PLC controller is used for presetting program, controlling automatic switching of the crushing mode and the residual cleaning mode, and the man-machine interface is used for setting parameters (such as refrigerant temperature and cleaning period) and displaying the equipment state.

[0041] After the refrigerator injects the refrigerant into the cavity of the tooth roller, the cavity is gradually filled with the refrigerant, and under the rotation of the tooth roller, the refrigerant is distributed in the outer circle of the cavity under the action of centrifugal force, so as to cool the tooth roller.

[0042] The working principle of the coal slime freeze-thaw residual cleaning device is as follows: the high viscosity of coal slime is mainly caused by the complex colloid system formed by the internal capillary water, combined water and clay minerals. Through deep cooling treatment, the water in the coal slime rapidly crystallizes into ice, which physically destroys the key structure that maintains its viscosity: first, the growth of ice crystals breaks the liquid bridge connection between coal slime particles, eliminating the main source of adhesion; second, the volume of water expands when it freezes, causing small stress cracks in the coal slime, making it brittle from ductile, and fundamentally changing its mechanical properties. Finally, the frozen coal slime changes from a viscoplastic body to a brittle body, and its adhesion to the surface of the device is significantly reduced, so that it is easy to clean and fall off through crushing or slight external force.

[0043] A residual cleaning method of a coal slime freeze-thaw residual cleaning device, comprising the following steps:

[0044] Step S1, crushing and real-time anti-sticking;

[0045] S1.1, the slime is normally sent into the double-toothed roller crusher for crushing;

[0046] S1.2, in this process, the low-temperature refrigerant continuously circulates in the hollow toothed roller;

[0047] S1.3, the refrigerant quickly conducts heat away through the roller wall, the temperature of the toothed roller surface is reduced, and a thin layer of slime in contact with or just adhered to the toothed roller surface is quickly cooled below the freezing point;

[0048] S1.4, the surface moisture of the slime freezes, the adhesion is reduced, and the slime is crushed under the action of the two toothed rollers.

[0049] S2, finishing and residual cleaning;

[0050] S2.1, when the crushing operation is completed or needs to be cleaned, the adjusting control system is adjusted, and the device enters the finishing and residual cleaning stage;

[0051] S2.2, the control system automatically switches the valve to stop the refrigerant from being supplied;

[0052] S2.3, the high-frequency coil is started, and the high-frequency coil heats and acts on the toothed roller to instantaneously heat the roller teeth to 5-10℃.

[0053] In step S1, the anti-sticking mechanism of the slime is: 1, the surface moisture of the slime instantaneously freezes, destroying the adhesive network composed of liquid bridge force and surface tension inside the slime, so that the slime changes from a "viscoplastic" state to a "brittle" state; 2, the frozen slime slightly swells in volume, and the mechanical meshing action of the slime with the metal toothed roller surface is partially isolated by the ice crystal layer, and the adhesion is greatly reduced; 3, the adhered layer in the brittle state is more easily flaked or granulated under the subsequent extrusion and flushing of the material and the shearing action of the toothed rollers, thereby effectively inhibiting the accumulation of the adhered layer and realizing real-time anti-sticking in the crushing process.

[0054] In step S2, the mechanism of residual cleaning is: 1, heat is accurately transferred to the coal slime-toothed roller interface, so that the extremely thin ice layer there is rapidly melted into a micron-level water film, losing adhesion; 2, lubrication and flaking: the water film plays a good lubricating role, so that the adhesion of the frozen slime block to the roller surface is suddenly reduced; 3, self-weight and centrifugal force flaking: under the action of gravity and centrifugal force, the whole piece of frozen slime is automatically peeled off from the roller surface, realizing complete and efficient self-cleaning.

[0055] In addition, after the high-frequency coil is turned on, the refrigeration cycle system has been closed, but the refrigerant still flows in the pipeline. The refrigerant heated by the high-frequency coil has a reduced density and is pushed to the center by the centrifugal force, and flows back to the refrigeration unit from the liquid return pipe.

[0056] In the embodiment, the refrigerant is calcium chloride brine. In another embodiment, the refrigerant is an antifreeze solution such as ethylene glycol solution. Meanwhile, in addition to the high frequency coil heating, hot water, heat conducting oil or low pressure steam can also be used as the heat medium, and the above cooling pipeline system is used for heating. In addition to triggering according to the time period, the residual cleaning instruction can also be automatically triggered by monitoring the motor torque (the increase of the torque indicates that the adhesion is serious), which is more intelligent and energy-saving.

[0057] The above are preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. In the above, the same parts are indicated by the same reference numerals. It should be noted that the words "front", "back", "left", "right", "up" and "down" used in the following description refer to the directions in the drawings, and the words "inner" and "outer" refer to the directions towards or away from the geometric center of a specific part. Therefore, any equivalent changes made according to the structure, shape and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A coal slime freeze-thaw cleaning device, characterized in that, It comprises a hollow tooth roller system, a refrigeration circulation system and a control system. The hollow tooth roller system comprises a frame, tooth rollers, bearing seats, hollow shafts and high-frequency coils, the tooth rollers are symmetrically arranged and meshed with each other, the two tooth rollers are installed in parallel in the frame and form a crushing cavity, the tooth rollers are hollow and have cavities, the bearing seats are installed on both sides of the frame, the hollow shafts are inserted into the bearing seats and the shafts of the tooth rollers to realize the rotation of the tooth rollers, the hollow shafts are open at both ends, and the high-frequency coils are arranged on the frame and close to the tooth rollers. The refrigeration circulation system comprises cold coals, rotary joints, liquid supply pipes and refrigerators, the refrigerators are arranged outside independently of the frame, one end of the liquid supply pipe is connected to the refrigerator and the other end is connected to the rotary joint, the rotary joint is inserted into the hollow shaft and communicates with the cavities of the tooth rollers, and the cold coals flow in the rotary joint, the liquid supply pipe, the refrigerator and the cavities. The control system comprises a PLC controller and temperature sensors, the temperature sensors are used for detecting temperature, and the PLC controller is used for mode switching and switching of the device.

2. The coal slime freeze-thaw residual cleaning device according to claim 1, characterized in that, The tooth rollers are made of high-strength alloy steel with high thermal conductivity.

3. The coal slime freeze-thaw residual cleaning device according to claim 1, characterized in that, The high-frequency coils are arranged on the frame away from the meshing positions of the two tooth rollers.

4. The coal slime freeze-thaw residual cleaning device according to claim 1, characterized in that, The rotary joints are arranged in two and are inserted into the hollow shafts from both ends, and the rotary joints have connecting pipes which communicate with the cavities of the tooth rollers.

5. The coal slime freeze-thaw residual cleaning device according to claim 1, characterized in that, The refrigeration circulation system further comprises a liquid return pipe, one rotary joint is connected to the liquid supply pipe, and the other rotary joint is connected to the liquid return pipe.

6. The coal slime freeze-thaw residual cleaning device according to claim 5, characterized in that, Stop valves and temperature sensors are arranged on the liquid return pipe and the liquid supply pipe.

7. The coal slime freeze-thaw residual cleaning device according to claim 1, characterized in that, The refrigerant is calcium chloride brine.

8. A method for cleaning residues based on the device for cleaning residues according to any one of claims 1 to 7, characterized in that, It comprises the following steps: S1, crushing and real-time anti-sticking; S1.1, the coal slime is normally fed into the double-tooth roller crusher for crushing; S1.2, the low-temperature refrigerant continuously circulates in the hollow tooth roller; S1.3, the temperature of the surface of the tooth roller is reduced, so that a thin layer of coal slime in contact with or just adhered to the surface of the tooth roller is rapidly cooled below the freezing point; S2, finishing and residual cleaning; S2.1, the control system automatically switches the valve to stop the refrigerant from being supplied; S2.2, the high-frequency coil is started, and the high-frequency coil acts on the tooth roller to instantaneously heat the tooth to 5-10℃.

9. The method of claim 8, wherein the coal slime freeze-thaw residual cleaning device is characterized by, Step S1 further comprises S1.4, the surface moisture of the coal slime is frozen, the adhesion is reduced, and the coal slime is crushed under the action of the two tooth rollers.

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