Intelligent regulation and control method and regulation and control system for concentrating, settling and compacting area of rake thickener

Abstract

The invention provides an intelligent regulation and control method for a concentrating and settling dense area of a rake thickener. The method comprises the following steps: obtaining a corresponding maximum thickness value of the dense area when a thickener rake frame in the dense area normally works; obtaining a linear relation between the thickness of the dense area and the corresponding underflow concentration of the dense area through limited times of tests, obtaining the underflow concentration value of the dense area corresponding to the maximum thickness value of the dense area in the non-raking state of the dense area, and recording the concentration value as C set; detecting the real-time concentration value of the dense area in real time through a concentration detection unit, and recording the real-time concentration value as C detection; according to the difference value between the C < measured > and the C < set >, the frequency of the variable frequency pump is regulated and controlled online, and the real-time underflow discharging speed is regulated and controlled, so that the thickness value of the dense area in the thickener is kept below the maximum thickness value of the dense area without pressing the rake. The invention further provides a system based on the method, the problem of rake pressing cannot be generated, and meanwhile the labor cost and the time cost are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of mineral processing and ore dressing, and in particular to an intelligent control method and control system for a thickening, settling and compacting zone of a rake-type thickener. Background Art

[0002] In the process of wet coal sorting, the (tail) coal slime in the coal slime particles and the washing water are settled and the solid-liquid separated through a concentrator. At this time, three layers will appear in the concentrator: the clarification zone, the effective sedimentation zone and the compaction zone. In the clarification zone, recyclable circulating water (concentrator clarification overflow) is finally obtained, and in the compaction zone, coal slime containing a certain amount of water (concentrator underflow) is finally obtained.

[0003] In order to ensure that the circulating water overflowing from the concentrator can reach a low concentration, flocculants and coagulants are usually added to the feed end of the concentrator. The purpose is to make the coal slime quickly settle to the dense area at the bottom of the concentrator, so that the concentration in the clarification area above the concentrator can be as low as possible to meet the requirements for the recycling of circulating water.

[0004] When the amount of coal slime generated during underground mining or tunneling is large, the amount of coal slime in the system will also increase accordingly. In order to ensure that the overflow circulating water concentration meets the requirements, the coal preparation plant usually increases the amount of flocculants and coagulants so that the overflow water meets the circulating concentration requirements. At this time, a large amount of coal slime will settle in the concentrator, which will cause the coal slime in the bottom flow dense zone of the concentrator to accumulate and increase over a certain period of time. However, since the external discharge output flow of the concentrator is fixed, when the coal slime in the bottom flow dense zone of the concentrator increases to a certain extent, the coal slime in the dense zone will produce too much resistance, which will make the rake frame of the bottom scraper of the concentrator unable to move and work normally, commonly known as a rake pressure accident. Figure 3 As shown, at this time, the only thing that can be done is to empty the thickening tank and inspect the rake frame, which will incur a lot of manpower and time costs. If there is no spare equipment, it will cause the entire plant to shut down and even restrict underground production, causing huge economic losses to the coal mine. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an intelligent control method and control system for the thickening, settling and compacting zone of a rake-type thickener. By real-time monitoring of the underflow of the thickener, the discharge volume of the underflow of the thickener is controlled in real time according to the difference between the concentration value of the underflow of the thickener and the pressure borne by the rake frame of the thickener, and the problem of rake pressure will not occur. At the same time, the labor cost and time cost are also reduced, and continuous production can be achieved without stopping, thus avoiding the economic losses caused by stopping.

[0006] In order to solve the above technical problems, the first technical solution provided by the present invention is to provide an intelligent control method for the concentration sedimentation and compaction zone of a rake thickener, which is used to control the thickness of the compaction zone in the rake thickener so that the rake frame in the thickener can work normally. The bottom of the rake thickener is provided with a variable frequency pump for underflow discharge. The control method comprises the following steps:

[0007] Obtain the maximum value of the compacted area thickness corresponding to the normal operation of the thickener rake in the compacted area;

[0008] The linear relationship between the thickness of the dense zone and the corresponding underflow concentration of the dense zone is obtained through a finite number of tests, and the underflow concentration value of the dense zone corresponding to the maximum value of the thickness of the dense zone without rake pressure in the dense zone is obtained, and this concentration value is defined as the set value of the underflow concentration of the dense zone, denoted as C 设 ;

[0009] The real-time concentration value of the dense zone is detected by the concentration detection unit in real time, and the real-time concentration value is defined as the measured value of the bottom flow concentration of the dense zone, denoted as C 测 ;

[0010] According to C 测 With C 设 The difference between the two is used to adjust the frequency of the variable frequency pump online to adjust the real-time underflow discharge speed so that the thickness of the dense zone in the concentrator is maintained below the maximum thickness of the dense zone without rake pressure.

[0011] Preferably, the linear relationship between the thickness of the dense zone and the bottom flow concentration of the dense zone is thickness=K×concentration+B, wherein K is ±3.5 and B is ±20.

[0012] Preferably, when C 测 With C 设 When the difference is greater than +30%, the frequency of the variable frequency pump increases by 20%; when C 测 With C 设 When the difference is 0~+30%, the frequency of the variable frequency pump increases by 10%; when C 测 With C 设 When the difference is 0~-30%, the frequency of the variable frequency pump is reduced by 10%; when C 测 With C 设 When the difference is less than -30%, the frequency of the variable frequency pump is reduced by 20%.

[0013] Preferably, the variable frequency of the variable frequency pump is 30 Hz to 50 Hz.

[0014] Preferably, the variable frequency pump realizes real-time control of the frequency of the variable frequency pump through a PLC control unit.

[0015] The second technical solution provided by the present invention is to provide a control system for an intelligent control method of a thickening, settling and compacting zone of a rake thickener, comprising:

[0016] A thickener is used to settle the coal slime under the action of the added reagent, and to separate the coal slime water fed into the thickener into a clarification zone, an effective settling zone and a compacting zone from top to bottom. A rake is provided at the compacting zone of the thickener, and a conveying pipe is provided at the bottom of the thickener;

[0017] A variable frequency pump connected to the output end of the delivery pipe is used to discharge the settled coal slime in the dense zone of the concentrator to reduce the thickness of the dense zone of the concentrator;

[0018] The concentration detection unit is installed on the delivery pipe between the concentrator and the variable frequency pump, and is used to detect the concentration of the coal slime flowing out of the compaction area;

[0019] The variable frequency pump control unit is connected to the variable frequency pump and is used to control the frequency of the variable frequency pump.

[0020] Preferably, the variable frequency pump control unit is a PLC control unit.

[0021] Preferably, an overflow weir is provided on the top of the concentrator to discharge water from the clarification zone in the concentrator into the circulation pool.

[0022] Preferably, the variable frequency pump is connected to the filter press workshop through a pipeline.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention obtains the density concentration value of the dense area corresponding to the maximum density thickness of the dense area when the thickener rake frame in the dense area works normally, which is C 设 , then compare C 设 The difference between the real-time concentration value of the dense area detected by the concentration detection unit and the real-time online adjustment of the frequency of the variable frequency pump is used to maintain the thickness value of the dense area in the concentrator below the maximum thickness of the dense area without rake pressure, thereby adjusting the discharge volume of the bottom flow of the concentrator in real time without causing rake pressure problems, while also reducing labor costs and time costs, enabling continuous production without stopping, and avoiding economic losses caused by stopping.

[0025] 2. The present invention can ensure that when the amount of raw coal slime fluctuates, the amount of coal slime deposited in the concentrator can be accurately grasped through real-time detection and monitoring of the underflow concentration. When the amount of coal slime increases, the frequency of the variable frequency pump can be increased in time to timely reduce the height of the underflow dense zone of the concentrator, ensure the height stability of the dense zone of the concentrator, and then achieve the stability of the functional space height of each part of the concentrator, so that the height of the sedimentation zone and the clarification zone is also relatively stable, and the sedimentation effect of the concentrator is guaranteed. The purpose of reducing the pressure load of the rake frame is to avoid the coal slime rake pressure accident caused by the high thickness of the dense zone, reduce the occurrence of accidents of the concentrator, reduce the loss of coal mines and coal preparation plants, and improve economic benefits. When the amount of coal slime decreases, the frequency of the variable frequency pump can be reduced to reduce the underflow discharge, so that the concentrator is in a stable working state, avoid the dense zone is too low to cause the variable frequency pump to pump water, and affect the stability of the flow field in the sedimentation zone, so as to ensure the sedimentation effect of the concentrator. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A structural schematic diagram of an intelligent control system for a concentrating, settling and compacting zone of a rake-type concentrator of the present invention.

[0028] Figure 2 As the amount of coal slime increases, the amount of flocculant and coagulant added to the concentrator increases, resulting in changes in the clarification area, effective sedimentation area and compaction area in the concentrator.

[0029] Figure 3 The invention discloses a control system for the thickening, settling and compacting zone of a rake thickener in the prior art.

[0030] Reference numerals

[0031] 1. Concentrator, 2. Delivery pipe, 3. Variable frequency pump, 4. Concentration detection unit, 5. Variable frequency pump control unit, 6. Fixed flow pump, 7. Clarification zone, 8. Effective sedimentation zone, 9. Densification zone. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned purposes, features and advantages of the embodiments of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention. All other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The inventors discovered that due to the fixed external output flow rate of the concentrator, when the coal slime in the dense zone of the bottom flow of the concentrator increases to a certain extent, the coal slime in the dense zone will produce too much resistance, making it impossible for the rake frame that scrapes the material at the bottom of the concentrator to move and work normally, commonly known as a rake pressure accident. At this time, the rake frame can only be emptied from the concentrator tank for inspection, which will incur a lot of manpower and time costs. If there is no spare equipment, it will cause the entire plant to shut down and even restrict underground production, causing huge economic losses to the coal mine.

[0034] In view of this, the present invention provides an intelligent control method and control method for the thickening, settling and compacting zone of a rake-type thickener. By real-time monitoring of the underflow of the thickener, the discharge volume of the underflow of the thickener is controlled in real time according to the difference between the concentration value of the underflow of the thickener and the pressure borne by the rake frame of the thickener. The problem of rake pressure will not occur, and the labor cost and time cost are also reduced. Continuous production can be achieved without stopping the machine, thus avoiding the economic losses caused by stopping the machine.

[0035] like Figure 1 As shown, the present invention provides an intelligent control method for the concentration sedimentation and compaction zone of a rake thickener, which is used to control the thickness of the compaction zone in the rake thickener so that the rake frame in the thickener works normally. The bottom of the rake thickener is provided with a variable frequency pump for underflow discharge. The control method comprises the following steps:

[0036] Obtain the maximum value of the compacted area thickness corresponding to the normal operation of the thickener rake in the compacted area;

[0037] The linear relationship between the thickness of the dense zone and the corresponding underflow concentration of the dense zone is obtained through a finite number of tests, and the underflow concentration value of the dense zone corresponding to the maximum value of the thickness of the dense zone without rake pressure in the dense zone is obtained, and this concentration value is defined as the set value of the underflow concentration of the dense zone, denoted as C 设 ;

[0038] The real-time concentration value of the dense zone is detected by the concentration detection unit in real time, and the real-time concentration value is defined as the measured value of the bottom flow concentration of the dense zone, denoted as C 测 ;

[0039] According to C 测 With C 设 The difference between the two is used to adjust the frequency of the variable frequency pump online to adjust the real-time underflow discharge speed so that the thickness of the dense zone in the concentrator is maintained below the maximum thickness of the dense zone without rake pressure.

[0040] Specifically, the linear relationship between the thickness of the dense area and the bottom flow concentration of the dense area is thickness=K×concentration+B, wherein K is ±3.5 and B is ±20.

[0041] Specifically, when C 测 With C 设When the difference is greater than +30%, the frequency of the variable frequency pump increases by 20%; when C 测 With C 设 When the difference is 0~+30%, the frequency of the variable frequency pump increases by 10%; when C 测 With C 设 When the difference is 0~-30%, the frequency of the variable frequency pump is reduced by 10%; when C 测 With C 设 When the difference is less than -30%, the frequency of the variable frequency pump is reduced by 20%.

[0042] Specifically, the variable frequency of the variable frequency pump is 30 Hz to 50 Hz.

[0043] Specifically, the frequency conversion pump realizes real-time control of the frequency of the frequency conversion pump through the PLC control unit. The PLC control unit can realize accurate automatic control of the frequency conversion pump 3, so that the discharge volume of the concentrator underflow can be adjusted in real time, so that there will be no rake pressure problem in the concentrator.

[0044] A control system for an intelligent control method for a thickening, settling and compacting zone of a rake thickener comprises: a thickener 1, a variable frequency pump 3, a concentration detection unit 4 and a variable frequency pump control unit 5, wherein:

[0045] The thickener 1 is used to settle the coal slime under the action of the added reagent, and separate the coal slime water fed into the thickener 1 into a clarification zone 7, an effective settling zone 8 and a compacting zone 9 from top to bottom. A rake is provided at the compacting zone 9 of the thickener 1, and a conveying pipe 2 is provided at the bottom of the thickener 1;

[0046] The variable frequency pump 3 is connected to the output end of the delivery pipe 2 and is used to discharge the settled coal slime in the dense zone 9 of the thickener 1 so as to reduce the thickness of the dense zone 9 of the thickener 1;

[0047] The concentration detection unit 4 is arranged on the delivery pipe 2 between the concentrator 1 and the variable frequency pump 3, and is used to detect the concentration of the coal slime flowing out of the dense area; the concentration detection unit 4 here is a concentration meter, and the specific model is purchased according to actual needs.

[0048] The variable frequency pump control unit 5 is connected to the variable frequency pump 3 and is used to control the frequency of the variable frequency pump 3 .

[0049] When in use, the model of the variable frequency pump 3 and the variable frequency pump control unit 5 need to be reasonably selected according to the size of the concentrator 1 so that the concentrator 1 matches the variable frequency pump 3 and the variable frequency pump control unit 5 .

[0050] Specifically, the variable frequency pump control unit 5 is a PLC control unit.

[0051] Specifically, an overflow weir is provided on the top of the concentrator 1 to discharge the water in the clarification area of ​​the concentrator 1 into the circulation pool.

[0052] Specifically, the variable frequency pump 3 is connected to the filter press workshop through a pipeline to reuse the discharged coal slime.

[0053] Working principle:

[0054] When a large amount of coal slime is generated during underground mining or excavation, the amount of coal slime in the system increases. In order to ensure that the overflow circulating water concentration meets the requirements, the coal preparation plant usually increases the amount of flocculants and coagulants to make the overflow water meet the circulating concentration requirements. When the coal slime water (a mixture of coal and water) enters the concentrator, under the action of flocculants and coagulants, the coal slime settles from top to bottom. Under the action of coagulants and flocculants, there is almost no coal slime on the upper part of the concentrator, only water with extremely low concentration forms a clearing area 7 and eventually becomes overflow, which is discharged into the circulating water pool through the top overflow weir. Most of the sedimentation of coal slime occurs in the middle area of ​​the concentrator, which is called the effective sedimentation area 8. After the coal slime particles settle to the bottom, they continue to accumulate to form a dense area 9, and finally the rake is driven by the rake frame to scrape to the center, and the variable frequency pump is discharged to the filter press workshop for deep dehydration.

[0055] However, since the variable frequency pump of the concentrator usually adopts a fixed flow pump, such as Figure 3 As shown in the figure, when a large amount of coal slime settles, the coal slime in the dense area of ​​the bottom flow will accumulate and increase in a certain period of time. At this time, when the dosage of flocculants and coagulants increases to a certain extent, the coal slime in the dense area will produce too much resistance, which will make the rake frame of the bottom scraper of the thickener unable to move and work normally, commonly known as the rake pressure accident. Figure 2-Figure 3 As shown, the reasons for the above problems are:

[0056] (1) Coal preparation plants rarely use means to monitor the underflow status; (2) Even if the concentrator is equipped with a rake pressure measurement device, there is no way to solve this problem when continuous production cannot be stopped, and hidden dangers still exist; (3) The underflow discharge uses a fixed-flow pump, and there is no feedback response to the underflow status; (4) Currently, most of the treatment in coal preparation plants is done by manual operation, and the coal slurry lacks the ability to adapt intelligently in real time online.

[0057] In order to solve the above problems, the present invention improves the existing control system and control method. Figure 1 Provided is an intelligent control method for the concentration sedimentation and compaction zone of a rake thickener, which is used to control the thickness of the compaction zone in the rake thickener so that the rake frame in the thickener can work normally. The bottom of the rake thickener is provided with a variable frequency pump for underflow discharge. The control method comprises the following steps:

[0058] Obtaining the maximum value of the thickness of the compacting zone 9 corresponding to the normal operation of the thickener rake in the compacting zone;

[0059] The linear relationship between the thickness of the dense area 9 and the corresponding underflow concentration of the dense area 9 is obtained through a limited number of tests. The linear formula is: thickness = 3.5 × concentration + 20. The underflow concentration value of the dense area 9 corresponding to the maximum thickness of the dense area 9 without raking is obtained, and this concentration value is defined as the set value of the underflow concentration of the dense area 9, recorded as C 设 ;

[0060] The real-time concentration value of the dense zone is detected by the concentration detection unit in real time, and the real-time concentration value is defined as the measured value of the bottom flow concentration of the dense zone, denoted as C 测 ;

[0061] According to C 测 With C 设 The difference between the two is used to achieve real-time control of the frequency of the variable frequency pump 3 through the PLC control unit, which is used to adjust the underflow discharge speed in real time online so that the thickness of the dense area 9 in the thickener is maintained below the maximum thickness of the dense area 9. In this way, the discharge volume of the underflow of the thickener 1 can be adjusted in real time, and the rake pressure problem will not occur. At the same time, the labor cost and time cost are also reduced, and continuous production can be achieved without stopping, thus avoiding the economic losses caused by stopping.

[0062] When C 测 With C 设 When the difference is greater than +30%, the frequency of variable frequency pump 3 increases by 20%; when C 测 With C 设 When the difference is 0~+30%, the frequency of variable frequency pump 3 increases by 10%; when C 测 With C 设 When the difference is 0~-30%, the frequency of variable frequency pump 3 is reduced by 10%; when C 测 With C 设 When the difference is less than -30%, the frequency of variable frequency pump 3 is reduced by 20%.

[0063] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for intelligently controlling the concentration, settling and compacting zone of a rake thickener, characterized in that: The method is used to control the thickness of the compacted area in the rake thickener so that the rake frame in the thickener works normally. The bottom of the rake thickener is provided with a variable frequency pump for underflow discharge. The control method includes the following steps: Obtain the maximum value of the compacted area thickness corresponding to the normal operation of the thickener rake in the compacted area; The linear relationship between the thickness of the dense zone and the corresponding underflow concentration of the dense zone is obtained through a finite number of tests, and the underflow concentration value of the dense zone corresponding to the maximum value of the thickness of the dense zone without rake pressure in the dense zone is obtained, and this concentration value is defined as the set value of the underflow concentration of the dense zone, denoted as C 设 ; The real-time concentration value of the dense zone is detected by the concentration detection unit in real time, and the real-time concentration value is defined as the measured value of the bottom flow concentration of the dense zone, denoted as C 测 ; According to C 测 With C 设 The difference between the two is used to adjust the frequency of the variable frequency pump online to adjust the real-time underflow discharge speed so that the thickness of the dense zone in the concentrator is maintained below the maximum thickness of the dense zone without rake pressure.

2. The method for intelligently controlling the concentration, settling and compacting zone of a rake thickener according to claim 1, characterized in that: The linear relationship between the thickness of the dense zone and the bottom flow concentration of the dense zone is thickness=K×concentration+B, where K is ±3.5 and B is ±20.

3. The method for intelligently controlling the concentration, settling and compacting zone of a rake thickener according to claim 1, characterized in that: When C 测 With C 设 When the difference is greater than +30%, the frequency of the variable frequency pump increases by 20%; when C 测 With C 设 When the difference is 0~+30%, the frequency of the variable frequency pump increases by 10%; when C 测 With C 设 When the difference is 0~-30%, the frequency of the variable frequency pump is reduced by 10%; when C 测 With C 设 When the difference is less than -30%, the frequency of the variable frequency pump is reduced by 20%.

4. The method for intelligently controlling the concentration, settling and compacting zone of a rake thickener according to claim 1, characterized in that: The variable frequency of the variable frequency pump is 30 Hz to 50 Hz.

5. The method for intelligently controlling the concentration, settling and compacting zone of a rake thickener according to claim 1, characterized in that: The variable frequency pump realizes real-time control of the frequency of the variable frequency pump through a PLC control unit.

6. A control system for an intelligent control method for a thickening, settling and compacting zone of a rake thickener according to any one of claims 1 to 5, characterized in that: include: The concentrator (1) is used to settle the coal slime under the action of the added reagent, and to separate the coal slime water fed into the concentrator (1) into a clarification zone (7), an effective settling zone (8) and a compacting zone (9) from top to bottom. A rake is provided at the compacting zone (9) of the concentrator (1), and a conveying pipe (2) is provided at the bottom of the concentrator (1); A variable frequency pump (3) is connected to the output end of the delivery pipe (2) and is used to discharge the settled coal slime in the dense zone of the thickener (1) so as to reduce the thickness of the dense zone (9) of the thickener (1); A concentration detection unit (4) is provided on the delivery pipe (2) between the concentrator (1) and the variable frequency pump (3) and is used to detect the concentration of the coal slime flowing out of the compacting area (9); The variable frequency pump control unit (5) is connected to the variable frequency pump (3) and is used to control the frequency of the variable frequency pump (3).

7. The control system of the intelligent control method for the thickening, settling and compacting zone of a rake thickener according to claim 6, characterized in that: The variable frequency pump control unit (5) is a PLC control unit.

8. The control system of the intelligent control method for the thickening, settling and compacting zone of a rake thickener according to claim 6, characterized in that: An overflow weir is provided on the top of the concentrator (1) for discharging water in the clarification zone of the concentrator (1) into a circulation pool.

9. The control system of the intelligent control method for the thickening, settling and compacting zone of a rake thickener according to claim 6, characterized in that: The variable frequency pump (3) is connected to the filter press workshop through a pipeline.

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