Clean coal flotation dehydration system and flotation dehydration process

Abstract

The invention provides a clean coal flotation dehydration system and a flotation dehydration process, and relates to the technical field of flotation coal washing. The clean coal flotation dehydration system comprises a flotation device and a dehydration device, wherein the flotation device is provided with a first input pipe; a medicament storage device is communicated; the centrifugal dehydrator is provided with a second input pipe, and the second input pipe can input flotation froth clean coal produced by the flotation device; the medicament heat supply unit is communicated with the centrifugal dehydrator, and the medicament heat supply unit can input and output centrifugate; the medicament heat supply unit is communicated with the water jacket layer of the medicament storage device and can output and input circulating water; wherein the agent heat supply unit is provided with a heat exchanger, and the heat exchanger can perform heat exchange between centrifugate and circulating water, so that a water jacket layer of the agent storage device can heat a floating chemical agent in the agent storage device through the circulating water; the solubility and dispersity of the chemical reagent for flotation can be improved, and the production efficiency and the energy utilization rate are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of flotation coal washing, in particular to a clean coal flotation dehydration system and a flotation dehydration process. Background Art

[0002] Coal washing, also known as coal preparation, primarily separates impurities from raw coal based on the density differences between the coal and impurities such as gangue. Coal washing is an essential process before coking. Coal is divided into raw coal and clean coal, with clean coal typically being the product of the coal washing process. Raw coal is generally used as a fuel and energy source, while clean coal is typically used in coking. It undergoes industrial processes such as water washing to remove sulfur and impurities to meet coking standards.

[0003] Flotation is a core step in the coal washing process, primarily used for separating fine and micro-particles. Clean coal flotation dewatering is a crucial step in coal flotation processing, aiming to reduce the moisture content of the clean coal through dehydration, thereby improving product quality and economic benefits. Common flotation dewatering processes include high-pressure pressing and air-through filter press dewatering, two-stage flotation clean coal dewatering, vibrating arc screen + coal slime centrifuge recovery of coarse clean coal, and centrifugal filtration dewatering of fine flotation clean coal hydrophobic agglomerates. However, in low-temperature environments, the solubility and dispersibility of flotation chemicals decrease. This is particularly true in regions such as Xinjiang, where diurnal temperature fluctuations are significant and winter minimum temperatures are low. The properties of flotation chemicals used in factories are significantly affected, reducing flotation efficiency. Conventional technologies can preheat the reagents using a heating device, but installing heating and insulation equipment inevitably results in additional energy consumption and increases factory operating costs. Summary of the Invention

[0004] The present invention aims to solve the problem in the prior art that the solubility and dispersibility of chemical reagents used for flotation in a low-temperature environment will decrease, thereby affecting the efficiency of the flotation operation. The present invention provides a clean coal flotation dehydration system and flotation dehydration process that can improve the solubility and dispersibility of chemical reagents used for flotation with poor solubility at low temperatures, thereby improving production efficiency and energy utilization and reducing waste.

[0005] The technical solution adopted in the present invention is:

[0006] A clean coal flotation dehydration system, comprising:

[0007] A flotation device having at least a first input pipe; and the flotation device is connected to a reagent storage device;

[0008] a centrifugal dehydrator having at least a second input pipe, the second input pipe being capable of inputting the flotation foamed clean coal produced by the flotation device; and

[0009] a medicine heating unit connected to the centrifugal dehydrator, capable of inputting and outputting centrifugal liquid; and connected to the water jacket layer of the medicine storage device, capable of outputting and inputting circulating water;

[0010] The medicine heating unit is provided with a heat exchanger, which can perform heat exchange between the centrifuge liquid and circulating water, so that the water jacket layer of the medicine storage device can heat the flotation chemical reagent in the medicine storage device through the circulating water.

[0011] Furthermore, it also includes:

[0012] The vibrating separation screen is used to screen the wet coal slime produced by water washing and sorting, output the coarse coal slime on the screen to the centrifugal dehydrator for coarse blending, and output the fine coal slime water under the screen to the flotation device for flotation operation.

[0013] Furthermore, it also includes:

[0014] A filter press is used to filter the coal slime water output by the flotation device and the centrifugal liquid output by the centrifugal dehydrator; the filter press has at least a third input pipe and a third output pipe; the third input pipe is connected to the flotation device and the reagent heating unit.

[0015] Furthermore, a ventilation pipe is provided on one side of the third output pipe; a control valve and a bypass branch are provided on the third input pipe; a bypass valve is provided on the bypass branch; and the ventilation pipe can allow back-blowing air to be introduced to back-blown the filter plates inside the filter press.

[0016] Furthermore, the heat exchanger is a plate heat exchanger; the plate heat exchanger is provided with a first input port, a second input port, a first output port and a second output port; the first input port is connected to the centrifugal dehydrator, the first output port is used to discharge the centrifugal liquid after heat exchange, and the second output port is connected to the water jacket layer of the medicine storage device; the medicine heating unit has at least a first circulating water pump; the input end of the first circulating water pump is connected to the water jacket layer of the medicine storage device, and the output end of the first circulating water pump is connected to the second input port.

[0017] Furthermore, the reagent heating unit also has at least a temperature control mechanism, which includes a PLC controller and a temperature sensor, and the temperature sensor is arranged at the second output port of the plate heat exchanger; the PLC controller is electrically connected to the temperature sensor and the first circulating water pump, and the temperature control mechanism can adjust the flow rate of the first circulating water pump by detecting the temperature of the circulating water at the second output port, thereby adjusting the temperature of the flotation chemical reagent in the reagent storage device.

[0018] Furthermore, a three-way valve is provided on the connecting pipeline between the second output port of the plate heat exchanger and the medicine storage device, and the branch pipe of the three-way valve is connected to the heating system; and the three-way valve is electrically connected to the temperature control mechanism, and the temperature control mechanism can detect the temperature of the circulating water at the second output port through the temperature sensor, and adjust the flow distribution on both sides of the three-way valve.

[0019] Furthermore, a filter is provided on the connecting pipeline between the centrifugal dehydrator and the plate heat exchanger.

[0020] A clean coal flotation dehydration process, using the clean coal flotation dehydration system described above, comprises the following steps:

[0021] S10. The wet coal slime produced by washing and sorting is added to the flotation device; and the reagent storage device is added to the flotation device for flotation chemical reagents, the flotation device flotates the wet coal slime, and produces flotation foam clean coal and coal slime water;

[0022] S20. The flotation foam clean coal is added to the centrifugal dehydrator, which dehydrates the flotation foam clean coal to obtain a clean coal slime product and discharges the centrifuge liquid;

[0023] S30. The centrifuge solution is passed into the reagent heating unit to heat the circulating water, and the reagent heating unit passes the circulating water into the reagent storage device to heat the flotation chemical reagent;

[0024] S40. The centrifugal liquid and coal slime water after heat exchange are recycled to the water washing and sorting process for recycling.

[0025] Further,

[0026] Wherein, the S10 comprises: adding the wet coal slime produced by water washing and sorting to the vibrating separation screen for screening, outputting coarse clean coal slime on the screen, and outputting fine clean coal slime water under the screen to the flotation device; and the reagent storage device adds flotation chemical reagents into the flotation device, and the flotation device floats the fine clean coal slime water to produce flotation foam clean coal and coal slime water;

[0027] The S20 includes: adding the flotation foam clean coal to the centrifugal dehydrator, and adding the coarse clean coal slime output from the vibrating separation screen to blend; the centrifugal dehydrator dehydrates the flotation foam clean coal and the coarse clean coal slime together to obtain a clean coal slime product, and discharges the centrifugal liquid.

[0028] The beneficial effects of the present invention are:

[0029] 1. The flotation dewatering system of the present invention relies on installing a reagent heating unit in a clean coal dewatering system composed mainly of a flotation device and a centrifugal dewatering machine. The reagent heating unit recovers waste heat from the centrifugal liquid produced by the centrifugal dewatering machine to heat circulating water. The circulating water is then passed into a reagent storage device for storing flotation chemical reagents in the flotation device to preheat the flotation chemical reagents. This enhances the solubility and dispersibility of the flotation chemical reagents and their interaction with mineral particles, improves flotation efficiency, and realizes the recovery of waste heat in the centrifugal liquid, thereby reducing energy waste and overall system energy consumption. This solves the problem in the prior art that the solubility and dispersibility of flotation chemical reagents decrease in low temperature environments, thereby affecting flotation efficiency.

[0030] 2. The flotation dehydration process of the present invention relies on the flotation dehydration system used therein to set a reagent heating unit in the clean coal dehydration system mainly composed of a flotation device and a centrifugal dehydrator. The reagent heating unit is used to recover the waste heat in the centrifuge produced by the centrifugal dehydrator to heat circulating water, which is then passed into a reagent storage device for storing flotation chemical reagents in the flotation device to preheat the flotation chemical reagents, thereby enhancing the solubility and dispersibility of the flotation chemical reagents and their interaction with mineral particles, improving the flotation efficiency, and realizing the recovery and utilization of waste heat in the centrifuge, reducing energy waste, and reducing the overall energy consumption of the system. This solves the problem in the prior art that the solubility and dispersibility of the flotation chemical reagents in a low temperature environment will be reduced, affecting the flotation operation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0032] Figure 1 Schematic diagram of the structure of the flotation dehydration system of Example 1 of the present invention;

[0033] Figure 2 Schematic diagram of a centrifugal dehydrator according to an embodiment of the present invention;

[0034] Figure 3 is a three-dimensional schematic diagram of a plate heat exchanger according to an embodiment of the present invention;

[0035] Figure 4 is a three-dimensional schematic diagram of a medicine storage device according to an embodiment of the present invention;

[0036] Figure 5 Schematic diagram of the structure of the flotation dehydration system of Example 2 of the present invention;

[0037] Figure 6 This is a structural diagram of a flotation dehydration system according to Example 3 of the present invention;

[0038] Figure 7 This is a flow chart of the flotation dehydration process of Example 4 of the present invention.

[0039] Reference numerals: 100 - vibrating separation screen;

[0040] 200 - flotation device, 210 - first input pipe, 220 - dosing pipe, 222 - third circulating water pump;

[0041] 300 - centrifugal dehydrator, 310 - centrifuge body, 312 - second input pipe, 314 - first output pipe, 316 - second output pipe, 320 - driving mechanism, 330 - mounting base;

[0042] 400 - filter press, 410 - third input pipe, 412 - control valve, 414 - second circulating water pump, 420 - third output pipe, 430 - ventilation pipe, 440 - bypass branch pipe, 442 - bypass valve;

[0043] 500 - pharmaceutical heating unit, 510 - filter, 520 - plate heat exchanger, 521 - fixed pressure plate, 522 - first input port, 523 - second input port, 524 - first output port, 525 - second output port, 526 - support rod, 527 - slide rail, 528 - movable pressure plate, 529 - plate, 530 - first circulating water pump, 531 - input port, 532 - output port, 540 - three-way valve;

[0044] 600-medicine storage device, 601-first medicine inlet, 602-second medicine inlet, 603-water inlet, 604-medicine outlet, 610-water jacket inlet, 620-water jacket outlet, 630-stirring mechanism;

[0045] 700-Heating system;

[0046] 800-secondary flotation equipment, 810-fourth input pipe, 820-reagent addition pipe. DETAILED DESCRIPTION

[0047] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0048] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention.

[0049] The embodiments of the invention are described in detail below with reference to the accompanying drawings.

[0050] Example 1

[0051] Existing flotation chemicals have reduced solubility and dispersibility at low temperatures. In existing technologies, flotation chemicals can be preheated using a heating device, but this inevitably results in additional energy consumption and increases plant operating costs.

[0052] To address the aforementioned issues in the prior art, a comprehensive study of clean coal dehydration systems revealed that the centrifugal fluid within the centrifugal equipment can maintain a relatively high temperature in a low-temperature environment, generating utilizable waste heat. Therefore, this embodiment provides a clean coal flotation dehydration system. This system is used to dehydrate wet clean coal slime after impurities have been separated during the washing process, yielding a clean coal product with a lower moisture content. This system can improve the solubility and dispersibility of flotation chemicals with poor solubility at low temperatures, thereby increasing production efficiency and energy utilization, and reducing waste. (See [the text] for more information.) Figures 1-4 The clean coal flotation dehydration system mainly includes: a vibrating separation screen 100, a flotation device 200, a centrifugal dehydrator 300, a filter press 400 and a reagent heating unit 500, etc.

[0053] The vibrating separation screen 100 is a vibrating curved screen used to screen the wet coal slime produced by water washing and sorting. The coarse coal slime is output from the screen to the centrifugal dewatering machine 300 for blending, and the fine coal slime water is output from the screen to the flotation device 200 for flotation. The vibrating separation screen 100 primarily consists of a feed box, a screen box, a screen mesh, and a vibrating mechanism. The vibrating separation screen 100 uses the vibration force provided by the vibrating mechanism to drive the screen surface to vibrate, evenly distributing the material on the screen surface. The screen bars cut the coal slime water, separating it. Under the action of vibration, the material gradually passes through the screen holes according to particle size, forming multiple graded products. In this embodiment, the curved design of the screen surface helps reduce adhesion and clogging, allowing the material to pass freely through the screen holes. At the same time, the vibrating separation screen 100 can effectively reduce the water content of the coarse clean coal slime by separating the coarse clean coal slime from the fine clean coal slime water and only input the fine clean coal slime water into the flotation device 200 for the flotation process, so that the final clean coal product has a lower water content, thereby reducing transportation costs and improving the quality of the clean coal product.

[0054] The flotation device 200 is used to flotate fine coal slurry and output frothy clean coal and coal slurry. The flotation cell of the flotation device 200 is equipped with a motor, a reducer, and an agitator shaft. The flotation cell is internally equipped with a stirring impeller and a bubble scraper. Furthermore, the sidewalls of the flotation device 200 are provided with a first inlet pipe 210 and a dosing pipe 220, which communicate with the interior of the flotation cell. The first inlet pipe 210 is used to add the fine coal slurry separated by the vibrating separation screen 100, allowing the fine coal slurry to enter the flotation cell for flotation. The dosing pipe 220 is used to add flotation chemicals such as collectors, foaming agents, and defoamers required for the flotation operation.

[0055] The centrifugal dehydrator 300 is used to receive the coarse clean coal slime from the vibrating separation screen 100 and the flotation foam clean coal from the flotation device 200, perform dehydration, output the clean coal slime product, and discharge the centrifuge liquid through the pipeline. Figure 1 、 Figure 2As shown in FIG, the centrifugal dehydrator 300 primarily comprises a centrifuge body 310, a drive mechanism 320, and other components. The centrifuge body 310 is generally cylindrical in shape, with a second inlet pipe 312 at one end for admitting coarse clean coal slime and flotation foamed clean coal. A first outlet pipe 314 and a second outlet pipe 316 are disposed on the sidewalls of the cylinder. Mounting blocks 330 are located at both ends of the centrifuge body 310, and a drive mechanism 320 is located at the bottom of the mounting block 330 at one end. The drive mechanism 320 comprises a motor and a reducer. Furthermore, a rotating shaft and a rotor, both in transmission connection with the drive mechanism 320, are located within the internal chamber of the centrifuge body 310. The rotor is driven to rotate by the drive mechanism 320, generating a strong centrifugal force through high-speed rotation, which separates particles or liquids of different densities from the liquid. The separated centrifuge liquid is discharged through the first outlet pipe 314, while the separated dehydrated clean coal slime is discharged through the second outlet pipe 316.

[0056] The filter press 400 is used to filter the coal slurry output from the flotation device 200 and the centrifuge output from the centrifugal dehydrator 300, recovering the remaining clean coal. The filter press 400 primarily comprises two support frames; a third input pipe 410 is provided on one support frame for inputting the coal slurry and centrifuge; a sliding track is provided between the two support frames, on which a number of filter plates and filter frames are slidably mounted; a hydraulic cylinder is provided on one support frame, and a pressure plate is provided on the telescopic end of the hydraulic cylinder. The pressure plate can drive the filter plates and filter frames to compress or expand, filtering the mixture within the filter chamber. The filtrate produced by the filtration is discharged through a third output pipe 420 at the bottom of the filter press 400. The filter cake produced by the filtration remains in the filter chamber and is removed after the filtration is completed.

[0057] In addition, in this embodiment, a reagent heating unit 500 is also provided. The reagent heating unit 500 is provided between the first output pipe 314 of the centrifuge 300 and the third input pipe 410 of the filter press 400, and is used to recover the waste heat in the centrifuge. The waste heat of the centrifuge is the result of the combined action of multiple factors such as mechanical friction and chemical reaction during the clean coal dehydration process. During the high-speed rotation of the centrifuge, the friction between the rotor and the material will generate heat, which will be transferred to the centrifuge to increase its temperature. The centrifuge may contain chemical substances, which may react chemically during the dehydration process to release heat. The reagent heating unit 500 mainly includes a plate heat exchanger 520, a first circulating water pump 530, a reagent storage device 600 and a temperature control mechanism. Figure 1 、 Figure 3As shown in FIG, the fixed pressing plate 521 of the plate heat exchanger 520 is provided with a first input port 522, a second input port 523, a first output port 524, and a second output port 525. The first input port 522 is connected to the first output pipe 314 of the centrifuge 300, and the first output port 524 is connected to the third input pipe 410 of the filter press 400. The first input port 522 and the first output port 524 are used to input and discharge the high-temperature centrifuge liquid. The second input port 523 is connected to the output end 532 of the first circulating water pump 530, and the second output port 525 is connected to the drug storage device 600. The second input port 523 and the second output port 525 are used to input and discharge circulating water. The circulating water exchanges heat with the centrifuge liquid in the plate heat exchanger 520 to increase its temperature. Meanwhile, the first circulating water pump 530 has an input end 531 and an output end 532. The input end 531 is connected to the reagent storage device 600, and the output end 532 is connected to the second input port 523 of the plate heat exchanger 520. The first circulating water pump 530 is used to drive circulating water to circulate between the plate heat exchanger 520 and the reagent storage device 600, thereby heating the reagent storage device 600. Furthermore, the reagent storage device 600 is generally cylindrical in shape and hollow inside. It is provided with a first reagent inlet 601 and a reagent outlet 604. The first reagent inlet 601 is used to add flotation chemical reagents for storage. The reagent outlet 604 is connected to the dosing pipe 220 of the flotation device 200 for adding the required chemical reagents during the flotation process. The sidewalls of the reagent storage device 600 are provided with a water jacket. The exterior of the sidewalls includes a water jacket inlet 610, which communicates with the second output port 525 of the plate heat exchanger 520, and a water jacket outlet 620, which communicates with the input port 531 of the first circulating water pump 530. Both the water jacket inlet 610 and the water jacket outlet 620 communicate with the interior of the water jacket, thereby heating the flotation chemical reagents stored within the reagent storage device 600. Furthermore, a temperature control mechanism (not shown) includes a PLC controller, a temperature sensor, and a flow meter. The PLC controller, the temperature sensor, the flow meter and the first circulating water pump 530 are all electrically connected. The temperature sensor is arranged at the second output port 525 of the plate heat exchanger 520. By detecting the temperature of the circulating water at the second output port 525, the flow rate of the first circulating water pump 530 is adjusted, thereby continuously preheating the flotation chemical reagents stored in the reagent storage device 600, keeping the temperature of the flotation chemical reagents stable and meeting the requirements, improving the solubility and dispersibility of the flotation chemical reagents, making them more evenly dispersed in water, thereby enhancing the interaction between the flotation chemical reagents and mineral particles and improving the flotation effect; and reducing the viscosity of the flotation chemical reagents and increasing their diffusion rate in water, thereby enhancing the interaction between the flotation chemical reagents and mineral particles and improving the flotation efficiency. Especially in a low temperature environment, this preheating method can significantly improve the flotation efficiency.

[0058] A specific working method of this embodiment is:

[0059] First, the wet coal slime produced by water washing and sorting is added to the vibrating separation screen 100 for screening, and the coarse clean coal slime on the screen is output to the centrifugal dehydrator 300 for blending, and the fine clean coal slime water under the screen is output to the flotation device 200; then, the reagent storage device 600 adds flotation chemical reagents into the flotation device 200, and the flotation device 200 floats the fine clean coal slime water to produce flotation foam clean coal and coal slime water; then, the flotation foam clean coal is also added to the centrifugal dehydrator 300, and the centrifugal dehydrator 300 floats the flotation foam clean coal. The foamed clean coal and coarse clean coal slime are dehydrated together to obtain a clean coal slime product, and the centrifuge liquid is discharged. Then, the centrifuge liquid is passed into the reagent heating unit 500 to heat the circulating water, and the reagent heating unit 500 passes the circulating water into the reagent storage device 600 to heat the flotation chemical reagent to improve the flotation efficiency. In addition, the centrifuge liquid and the coal slime water after heat exchange are passed into the filter press 400 for filtration. The obtained filtrate is recovered by the bucket elevator to the water washing and sorting process for further recycling, and the obtained filter cake is collected.

[0060] In this embodiment, the clean coal flotation dewatering system is configured by providing a reagent heating unit 500 in the clean coal separation and dewatering system mainly composed of a flotation device 200 and a centrifugal dewatering machine 300. The reagent heating unit 500 is used to recover waste heat from the centrifuge produced by the centrifugal dewatering machine 300 to heat circulating water. The circulating water is then passed into a reagent storage device 600 for storing flotation chemical reagents in the flotation device 200 to preheat the flotation chemical reagents. This enhances the solubility and dispersibility of the flotation chemical reagents and their interaction with mineral particles, thereby improving flotation efficiency. It also achieves the recovery of waste heat in the centrifuge, reduces energy waste, and lowers the overall energy consumption of the system. This solves the problem in the prior art that the solubility and dispersibility of flotation chemical reagents decrease in a low-temperature environment, thereby affecting the efficiency of the flotation operation.

[0061] At the same time, in this embodiment, by providing a vibrating separation screen 100, the coarse clean coal slime and the fine clean coal slime water are treated separately, thereby improving the flotation effect of the flotation device 200; and by providing a filter press 400, the clean coal in the centrifuge liquid and the coal slime water is recovered, thereby improving the clean coal recovery rate and reducing the waste of raw materials.

[0062] Specifically, in this embodiment, the particle size of the coarse coal slime separated by the vibrating separation screen 100 for blending is greater than 0.045 mm, and the particle size of the coal slime in the separated fine coal slime water is less than 0.045 mm. In one or more other embodiments, the particle size limit of the coal slime in the coarse coal slime and the fine coal slime water can be between 0.035 mm and 0.055 mm.

[0063] Specifically, the flotation device 200 in this embodiment is further provided with a tail coal filtering assembly (not shown in the figure). Since the unfloated gangue and impurities remain in the ore slurry, the tail coal filtering assembly first filters out the gangue and impurities and discharges them as tail coal. The coal slurry water obtained after filtration is then transported to the filter press 400 for filtration.

[0064] Specifically, the centrifugal dehydrator 300 in this embodiment has a drum speed of 1800-2200 rpm, a differential speed ratio of 1:25, a centrifugal intensity of 320±20, a solids recovery rate of ≥92%, and is equipped with a tungsten carbide screw propeller as its rotor. Preferably, the coarse clean coal slime on the screen and the flotation foam clean coal in this embodiment are blended in a ratio of 1:1.5 to 1:3. When the coarse clean coal slime and flotation foam clean coal are blended in a ratio of 1:2, the optimal dehydrated particle size composition is achieved within the centrifugal dehydrator 300.

[0065] Specifically, a ventilation pipe 430 is provided on the side of the third output pipe 420 of the filter press 400 in this embodiment, and a control valve 412 and a bypass branch pipe 440 are provided on the third input pipe 410 of the filter press 400. The bypass branch pipe 440 is also provided with a bypass valve 442. Therefore, when the filter press 400 is not feeding, backwash air can be introduced into the ventilation pipe 430. By closing the control valve 412 and opening the bypass valve 442, clean coal or impurities that are clogged between the filter plates of the filter press 400 are discharged through the bypass branch pipe 440. This prevents leakage and backflow caused by blockage, which could affect the operating efficiency of the filter press 400, thereby saving energy consumption and reducing the moisture content of the filter cake.

[0066] Specifically, the reagent heating unit 500 in this embodiment further includes a filter 510, which is disposed in the connecting pipe between the first output pipe 314 of the centrifugal dehydrator 300 and the first input port 522 of the plate heat exchanger 520. The filter 510 is used to filter solid particles remaining in the centrifuge liquid, thereby preventing solid particles from entering the interior of the plate heat exchanger 520 and causing internal damage to the plate heat exchanger 520. Furthermore, the filter 510 in this embodiment is a self-cleaning filter with a filtration accuracy of 100-200 μm and is equipped with a pressure-differential trigger backwash mechanism. When the inlet and outlet pressure differential exceeds 0.5 bar, backwashing is automatically initiated to discharge solid particles remaining within the filter. At the same time, the plate heat exchanger 520 has a wide flow channel plate structure. A support rod 526 is provided on the other end of the plate heat exchanger 520 opposite to the fixed pressure plate 521. Two slide rails 527 are provided between the fixed pressure plate 521 and the support rod 526. A movable pressure plate 528 is slidably provided on the slide rails. Hot and cold flow channels and a plurality of plates 529 are provided between the fixed pressure plate 521 and the movable pressure plate 528. The plates 529 are used for sufficient contact heat exchange between the centrifuge liquid and the circulating water. The material of the plate 529 is 316L stainless steel or titanium alloy. The heat exchange area of a single plate is 0.5~1.0 m², and the total heat transfer coefficient is 2500~3500 W / m²·℃.

[0067] Specifically, in this embodiment, in addition to the first circulating water pump 530, a second circulating water pump 414 is provided on the connecting line between the third input pipe 410 of the filter press 400 and the first output port 524 of the plate heat exchanger 520 for supplying liquid; and a third circulating water pump 222 is provided on the connecting line between the reagent outlet 604 of the reagent storage device 600 and the dosing pipe 220 of the flotation device 200 for supplying liquid.

[0068] Specifically, the water jacket of the reagent storage device 600 in this embodiment includes a stainless steel coil heat exchanger with a heat exchange area of 20-30 m². Furthermore, the reagent storage device 600 is equipped with a stirring mechanism 630, which primarily comprises a stirring motor and a reducer located above and outside the reagent storage device 600, as well as a stirring shaft and stirring blades located within the device. The stirring mechanism 630 is used to uniformly mix the flotation chemicals stored within the device 600 and improve the temperature uniformity of the stored flotation chemicals, thereby resolving the issue of poor fluidity and difficulty discharging local flotation chemicals at low temperatures. Furthermore, in addition to the first reagent inlet 601, the top of the reagent storage device 600 also features a second reagent inlet 602 and a water inlet 603, allowing for the simultaneous addition of multiple reagents, such as collectors and frothers, and the adjustment of concentration by adding water. Preferably, the outer wall of the medicine storage device 600 may be coated with a nano-aerogel insulation layer to achieve a heat loss rate of ≤3% / 24h. Baffles may also be provided inside the medicine storage device 600 to enhance heat exchange.

[0069] Example 2

[0070] In the above embodiment, although the problem of reduced solubility and dispersibility of chemical reagents used for flotation in a low-temperature environment, which affects the efficiency of the flotation operation, is solved by recovering the waste heat of the centrifuge 300, in some cases the recovery and utilization of the waste heat of the centrifuge cannot be fully satisfied, and the problem of energy waste still exists. In order to further improve the performance in terms of energy utilization on the basis of the first embodiment, a second embodiment is provided below.

[0071] See also Figure 5 The second embodiment is essentially identical to the first embodiment in structure and function with respect to the vibrating separation screen 100, flotation device 200, centrifuge 300, filter press 400, and reagent storage device 600. The primary difference between the second embodiment and the first is that the second embodiment also connects the reagent heating unit 500 to the production workshop's heating system 700, thereby fully utilizing the waste heat of the centrifuge liquid and improving energy efficiency.

[0072] Specifically, in this embodiment, a three-way valve 540 is installed in the connecting pipe between the second output port 525 of the plate heat exchanger 520 and the water jacket inlet 610 of the reagent storage device 600. A branch pipe from the three-way valve 540 connects to the floor heating network of the production workshop's heating system 700 to supplement heat. Furthermore, in this embodiment, the three-way valve 540 is an electrically controlled valve and is electrically connected to the temperature control mechanism of the clean coal flotation dehydration system. The temperature sensor of the temperature control system detects the temperature of the circulating water at the second output port 525 of the plate heat exchanger 520 and adjusts the flow distribution between the two sides. In operation, when the temperature of the circulating water at the second output port 525 is below 40°C, heat is preferentially distributed to the reagent storage device 600. When the temperature of the circulating water at the second output port 525 is above 45°C, excess heat is diverted to the production workshop's heating system 700.

[0073] In this embodiment, the clean coal flotation dehydration system is connected to the heating system 700 of the production workshop by disposing a three-way valve 540 between the plate heat exchanger 520 and the reagent storage device 600. The three-way valve 540 is adjusted by the temperature control mechanism of the clean coal flotation dehydration system. This solves the problem of not being able to fully recover and utilize the waste heat of the centrifuge liquid in the above-mentioned embodiment, and still causing energy waste.

[0074] Example 3

[0075] Based on the above embodiment, a variation is proposed, and a third embodiment is provided below.

[0076] See also Figure 6 The third embodiment is substantially identical to the first embodiment in structure and function with respect to the vibrating separation screen 100, flotation device 200, centrifugal dehydrator 300, reagent heating unit 500, and reagent storage device 600. The primary difference between the third embodiment and the first embodiment is that the third embodiment does not include the filter press 400, but does include a secondary flotation device 800.

[0077] like Figure 6As shown in FIG, the secondary flotation device 800 replaces the filter press 400 to recover clean coal from the centrifuge and coal slurry after heat exchange. The upper portion of the flotation cell of the secondary flotation device 800 is equipped with a motor, a reducer, and an agitator shaft; the interior of the flotation cell is equipped with a stirring impeller and a bubble scraper; and the sidewalls of the secondary flotation device 800 are provided with a fourth input pipe 810 and a reagent addition pipe 820, which communicate with the interior of the flotation cell. The fourth input pipe 810 is connected to the first output port 524 of the plate heat exchanger 520 and is used to receive the centrifuge after heat exchange. It can also be used to add coal slurry from the flotation device 200, thereby performing secondary flotation to recover clean coal. The reagent addition pipe 820 is connected to the reagent outlet 604 of the reagent storage device 600 and is used to add flotation chemicals such as collectors, frothers, and defoamers required for the flotation operation. In addition, the secondary flotation equipment 800 floats out secondary flotation foam clean coal and lower supernatant, wherein the secondary flotation foam clean coal is returned to the second input pipe 312 of the centrifugal dehydrator 300 for centrifugal dehydration again; the lower supernatant is recovered by the bucket elevator to the water washing and sorting process for further recycling.

[0078] In this embodiment, a secondary flotation device 800 is used to recover clean coal. Compared with the method of using a filter press 400 to recover clean coal in the first embodiment, the method of this embodiment can reduce equipment investment and eliminate the need for filter cake recovery, thereby reducing process complexity. The advantage of the method in the first embodiment is that the use of the filter press 400 can reduce the moisture content of the recovered clean coal and improve the quality of the clean coal product.

[0079] Example 4

[0080] On the basis of the above embodiments, a clean coal flotation dehydration process is further proposed, which is operated using the clean coal flotation dehydration system in the above embodiments. A fourth embodiment is provided below.

[0081] See also Figure 1 、 Figure 7 The clean coal flotation dehydration process in the fourth embodiment mainly includes the following steps:

[0082] S10. The wet coal slime produced by the water washing and sorting is fed to a vibrating separation screen 100 for screening. The coarse clean coal slime is discharged from the upper portion of the screen, and the fine clean coal slime water is discharged from the lower portion of the screen to the flotation device 200. The reagent storage device 600 then adds flotation chemicals to the flotation device 200. The flotation device 200 then flots the fine clean coal slime water, producing flotation foamed clean coal and coal slime water. In one or more alternative embodiments, the wet coal slime produced by the water washing and sorting may be fed directly to the flotation device 200 for flotation without screening by the vibrating separation screen 100.

[0083] S20. The flotation foamed clean coal is added to the centrifugal dehydrator 300, and the coarse clean coal slime output from the vibrating separation screen 100 is blended with the coarse coal. The centrifugal dehydrator 300 dehydrates the flotation foamed clean coal and the coarse clean coal slime together to obtain a clean coal slime product, and the centrifuge is discharged. In one or more alternative embodiments, when the vibrating separation screen 100 is not provided for screening, the flotation foamed clean coal can be directly added to the centrifugal dehydrator 300 without blending with the coarse coal.

[0084] S30. The centrifuge liquid is passed into the reagent heating unit 500 to heat the circulating water, and the reagent heating unit 500 passes the circulating water into the reagent storage device 600 to heat the flotation chemical reagent; thereby improving the solubility and dispersibility of the flotation chemical reagent and improving the flotation efficiency;

[0085] S40. The centrifuge liquid and the coal slurry water after heat exchange are passed through the filter press 400 for pressure filtration. The obtained filtrate is recycled to the water washing and sorting process through a bucket elevator for further recycling, and the obtained filter cake is collected. In one or more other embodiments, the centrifuge liquid and the coal slurry water after heat exchange can be directly recycled to the water washing and sorting process for further recycling without using the filter press 400 for pressure filtration. The advantage of this method is that it saves equipment investment and energy consumption, but the corresponding clean coal recovery rate will be reduced. Alternatively, referring to the third embodiment, a secondary flotation device 800 can be set to replace the filter press 400 to recover the clean coal in the centrifuge liquid and coal slurry water after heat exchange, and then the lower clear night can be recycled to the water washing and sorting process for further recycling.

[0086] In this embodiment, the clean coal flotation dewatering process uses a clean coal flotation dewatering system in which a reagent heating unit 500 is provided in the clean coal dewatering system mainly composed of a flotation device 200 and a centrifugal dewatering machine 300. The reagent heating unit 500 is used to recover waste heat from the centrifuge produced by the centrifugal dewatering machine 300 to heat circulating water. The circulating water is then passed into a reagent storage device 600 for storing flotation chemical reagents in the flotation device 200 to preheat the flotation chemical reagents, thereby enhancing the solubility and dispersibility of the flotation chemical reagents and their interaction with mineral particles, improving flotation efficiency, and realizing the recovery of waste heat in the centrifuge, thereby reducing energy waste and lowering the overall energy consumption of the system. This solves the problem in the prior art that the solubility and dispersibility of flotation chemical reagents are reduced in a low temperature environment, thereby affecting the flotation operation efficiency.

[0087] Specifically, in step S10 of this embodiment, the particle size of the coarse clean coal slime separated by the vibrating separation screen 100 for blending is greater than 0.045 mm, and the particle size of the coal slime in the separated fine clean coal slime water is less than 0.045 mm. In one or more other embodiments, the particle size limit of the coal slime in the coarse clean coal slime and the fine clean coal slime water can be between 0.035 mm and 0.055 mm. Furthermore, a filter assembly can be provided within the flotation device 200 to filter out the gangue and impurities remaining in the slurry before outputting the coal slime water.

[0088] Specifically, in S20 of this embodiment, the coarse clean coal slime on the screen and the flotation foam clean coal are mixed in a ratio of 1:1.5 to 1:3 to form an optimal dehydrated particle size composition in the centrifugal dehydrator 300.

[0089] Specifically, in S30 of this embodiment, the filter 510 may be used to filter and remove solid particles remaining in the centrifuge liquid to prevent the solid particles from entering the plate heat exchanger 520 and causing damage to the plate heat exchanger 520. In addition, a temperature control mechanism may be provided to detect the temperature of the circulating water at the second output port 525, and the flow rate of the first circulating water pump 530 may be adjusted in real time according to the temperature detection structure, thereby continuously preheating the flotation chemical reagent stored in the reagent storage device 600, maintaining the temperature of the flotation chemical reagent to meet the requirements, improving the solubility and dispersibility of the flotation chemical reagent, and making it more evenly dispersed in water, thereby enhancing the interaction between the flotation chemical reagent and the mineral particles and improving the flotation effect; and reducing the viscosity of the flotation chemical reagent and increasing its diffusion rate in water, thereby enhancing the interaction between the flotation chemical reagent and the mineral particles and improving the flotation efficiency.

[0090] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A clean coal flotation dehydration system, characterized in that: Include: A flotation device (200) having at least a first input pipe (210); and the flotation device (200) is connected to a reagent storage device (600); The centrifugal dehydrator (300) has at least a second input pipe (312), and the second input pipe (312) is capable of inputting the flotation foam clean coal produced by the flotation device (200); and A medicine heating unit (500) is connected to the centrifugal dehydrator (300), and the medicine heating unit (500) is capable of inputting and outputting centrifugal liquid; and the medicine heating unit (500) is connected to the water jacket layer of the medicine storage device (600), and the medicine heating unit (500) is capable of outputting and inputting circulating water; The reagent heating unit (500) is provided with a heat exchanger capable of exchanging heat between the centrifuge liquid and circulating water, so that the water jacket layer of the reagent storage device (600) can heat the flotation chemical reagent in the reagent storage device (600) through the circulating water.

2. The clean coal flotation dehydration system according to claim 1, characterized in that: Also includes: The vibrating separation screen (100) is used to screen the wet coal slime produced by water washing and sorting, outputting the coarse coal slime on the screen to the centrifugal dehydrator (300) for coarse blending, and outputting the fine coal slime water under the screen to the flotation device (200) for flotation operation.

3. The clean coal flotation dehydration system according to claim 1, characterized in that: Also includes: The filter press (400) is used for filtering the coal slurry output from the flotation device (200) and the centrifugal liquid output from the centrifugal dehydrator (300); the filter press (400) has at least a third input pipe (410) and a third output pipe (420); the third input pipe (410) is in communication with the flotation device (200) and the reagent heating unit (500).

4. The clean coal flotation dehydration system according to claim 3, characterized in that: A ventilation pipe (430) is provided on one side of the third output pipe (420); a control valve (412) and a bypass branch pipe (440) are provided on the third input pipe (410); a bypass valve (442) is provided on the bypass branch pipe (440); and the ventilation pipe (430) is capable of introducing backwash air to backwash the filter plates inside the filter press (400).

5. The clean coal flotation dehydration system according to claim 1, characterized in that: The heat exchanger is a plate-type heat exchanger (520); the plate-type heat exchanger (520) is provided with a first input port (522), a second input port (523), a first output port (524), and a second output port (525); the first input port (522) is communicated with the centrifugal dehydrator (300), the first output port (524) is used to discharge the centrifugal liquid after heat exchange, and the second output port (525) is communicated with the water jacket layer of the medicine storage device (600); the medicine heating unit (500) has at least a first circulating water pump (530); the input end of the first circulating water pump (530) is communicated with the water jacket layer of the medicine storage device (600), and the output end of the first circulating water pump (530) is communicated with the second input port (523).

6. The clean coal flotation dehydration system according to claim 5, characterized in that: The medicine heating unit (500) further comprises at least a temperature control mechanism, the temperature control mechanism comprising a PLC controller and a temperature sensor, the temperature sensor being arranged at the second output port (525) of the plate heat exchanger (520); the PLC controller being electrically connected to the temperature sensor and the first circulating water pump (530), and the temperature control mechanism being capable of adjusting the flow rate of the first circulating water pump (530) by detecting the temperature of the circulating water at the second output port (525), thereby regulating the temperature of the flotation chemical reagent in the medicine storage device (600).

7. The clean coal flotation dehydration system according to claim 6, characterized in that: A three-way valve (540) is provided on the connecting pipeline between the second output port (525) of the plate heat exchanger (520) and the medicine storage device (600), and a branch pipe of the three-way valve (540) is connected to the heating system (700); and the three-way valve (540) is electrically connected to the temperature control mechanism, and the temperature control mechanism can detect the temperature of the circulating water at the second output port (525) through the temperature sensor, and adjust the flow distribution on both sides of the three-way valve (540).

8. The clean coal flotation dehydration system according to claim 5, characterized in that: A filter (510) is provided on the communication pipeline between the centrifugal dehydrator (300) and the plate heat exchanger (520).

9. A clean coal flotation dehydration process, characterized in that: Using the clean coal flotation dehydration system according to any one of claims 1 to 8, the clean coal flotation dehydration process comprises the following steps: S10. adding the wet coal slime produced by water washing and sorting to the flotation device (200); and the reagent storage device (600) adding flotation chemical reagents into the flotation device (200), and the flotation device (200) flotating the wet coal slime to produce flotation foam clean coal and coal slime water; S20. adding the flotation foam clean coal to the centrifugal dehydrator (300), wherein the centrifugal dehydrator (300) dehydrates the flotation foam clean coal to obtain a clean coal slime product, and discharges the centrifuge liquid; S30. The centrifuge liquid is passed into the reagent heating unit (500) to heat the circulating water, and the reagent heating unit (500) passes the circulating water into the reagent storage device (600) to heat the flotation chemical reagent; S40. The centrifugal liquid and coal slime water after heat exchange are recycled to the water washing and sorting process for recycling.

10. The clean coal flotation dehydration process according to claim 9, characterized in that: Using the clean coal flotation dehydration system as claimed in claim 2; Wherein, the S10 comprises: adding the wet coal slime produced by water washing and sorting to the vibrating separation screen (100) for screening, outputting coarse clean coal slime on the screen, and outputting fine clean coal slime water under the screen to the flotation device (200); and the reagent storage device (600) adding flotation chemical reagents into the flotation device (200), and the flotation device (200) flotating the fine clean coal slime water to produce flotation foam clean coal and coal slime water; The S20 comprises: adding the flotation foam clean coal to the centrifugal dehydrator (300), and adding the coarse clean coal slime outputted from the vibrating separation screen (100) to perform coarse blending; the centrifugal dehydrator (300) dehydrates the flotation foam clean coal and the coarse clean coal slime together to obtain a clean coal slime product, and discharges the centrifugal liquid.

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