Method, system and equipment for predicting underflow concentration of coal slime thickener

Abstract

The invention discloses a method, system and equipment for predicting the underflow concentration of a coal slime thickener, and relates to the technical field of coal slime water treatment.The method comprises the steps that historical feeding data and chemical adding data of the thickener are obtained; calculating the total flow of settled coal slime settled to the bottom at the current moment and the amount of suspended coal slime accumulated in the thickener; calculating the total flow of the currently settled and bottomed coal slime according to the total flow of settled coal slime settled to the bottom of the thickener at the current moment and the accumulated amount of suspended coal slime; calculating the underflow sludge discharge flow according to the on-off state of the underflow pump of the thickener and the historical average underflow sludge discharge concentration; according to the current sludge storage total amount, the current total flow of the settled and bottomed coal slime and the underflow sludge discharge flow, the total mass of the settled sludge at the bottom of the thickener is calculated; predicting the concentration of the underflow coal slime according to the total mass of the sludge at the bottom of the thickener; the method can predict the concentration of the underflow of the thickener, and can be used for controlling the discharge of the underflow without frequently starting and stopping the underflow thickener through a heuristic method.

Description

Technical Field

[0001] The invention relates to the technical field of coal slime water treatment, and in particular to a method, system and equipment for predicting underflow concentration of a coal slime concentrator. Background Art

[0002] The most commonly used processes for treating coal slime water in coal preparation plants are concentration and filtration. In the concentration stage, low-concentration coal slime water is flocculated and settled by adding chemicals, so that the solid coal slime is enriched and settled to the bottom, and discharged as underflow into the subsequent filtration stage. At the same time, clarified water overflows from the top and is used as circulating water for upstream sorting processes.

[0003] In order to further improve production efficiency and make the filtration equipment work in the best working condition, it is necessary to provide a feed concentration suitable for the filtration equipment. Usually, if the concentration is too high, the filter cake formed by the filtration equipment will be thick, the filtration time will be long, and the moisture content will be high; if the concentration is too low, it will be difficult to form a filter cake, the filtration system will leak air, and the pressure cannot be maintained, which will also cause the filter cake moisture content to exceed the standard. Therefore, it is necessary to control the discharge timing of the underflow of the concentrator to maintain the underflow concentration within an appropriate range.

[0004] The current mainstream method is through trial and error, that is, after starting the discharge, the underflow concentration is tested according to the concentration meter installed on the underflow pipe. If it meets the requirements, the discharge is continued until the concentration is lower than the required concentration. If it does not meet the requirements, the discharge is stopped and another attempt is made after waiting for a period of time.

[0005] However, this method requires the discharged underflow to be returned to the concentration system, and the underflow pump must be started and stopped repeatedly, which has an adverse effect on the service life of the equipment and the stability of the system. Summary of the invention

[0006] In view of the disadvantage that the existing technology requires repeated starting and stopping of the underflow pump to predict the underflow concentration of the concentrator, which has an adverse effect on the service life of the equipment and the stability of the system, the present invention proposes a method, system and equipment for predicting the underflow concentration of the coal slime concentrator, which predicts the current underflow concentration according to the feed concentration, flow rate, dosing conditions and underflow discharge conditions of the concentrating system, thereby solving the problems existing in the prior art.

[0007] A method for predicting underflow concentration of a coal slime thickener comprises the following steps:

[0008] Obtaining historical feed data and dosing data of the concentrator; the dosing data includes the actual value and set value of the dosing amount, and the feed data includes the flow rate of the concentrator feed and the percentage of particles of different particle sizes in the feed to the total solids;

[0009] According to the historical feed data and dosing data of the concentrator, the total mass of the bottom sludge of the concentrator at the current moment is obtained; according to the total mass of the bottom sludge of the concentrator at the current moment, the underflow concentration is predicted;

[0010] The method of obtaining the total mass of the bottom sludge of the concentrator at the current moment according to the historical feed data and dosing data of the concentrator specifically includes the following steps:

[0011] According to the historical feed data and dosing data of the concentrator, the amount of coal slime settled to the bottom in the form of monomers and the amount of coal slime settled to the bottom in the form of flocs are obtained respectively, and the total settled coal slime flow rate settled to the bottom of the concentrator at the current moment is determined; the amount of coal slime settled to the bottom in the form of monomers is determined by the flow rate of the concentrator feed and the percentage of particles of the particle size grade in the feed to the total solids; the amount of coal slime settled to the bottom in the form of flocs is determined by the ratio of the actual value of the dosing amount to the set value;

[0012] According to the accumulated amount of monomeric coal slime that cannot settle in the concentrator without adding chemicals at the current moment and the flow rate of monomeric coal slime that cannot settle after starting to add chemicals and enters the settled coal slime after flocculation, the accumulated amount of suspended coal slime in the concentrator at the current moment is obtained;

[0013] The total mass of the sludge at the bottom of the concentrator is obtained according to the total settled coal slime flow rate settling to the bottom of the concentrator at the current moment, the accumulated suspended coal slime amount and the mud discharge flow rate of the underflow pump.

[0014] Further, the amount of coal slime settled to the bottom in the form of monomers is expressed as:

[0015]

[0016] in, Indicates the current time backward t x The flow rate of the concentrator feed in seconds, in m 3 / h;t x W represents the settling time required for the coal slime particles or flocs with particle size x to settle to the bottom in the thickener; sed,x It indicates the flow rate of coal slime monomer particles or flocs with particle size x at the current moment, which settles to the bottom, in kg / h; Indicates the current time backward t x The percentage of particles of size class x in the total solids in the feed to the concentrator at 1 second; Indicates the current time backward t x The actual value of the dosage at seconds, in L / min; Indicates the current time backward t x The dosage setting value at 1 second, in L / min;

[0017] The amount of coal slime settled to the bottom in the form of flocs is expressed as:

[0018]

[0019] Among them, W sed,0 It indicates the flow rate of coal sludge that the floccules settle to the bottom at the current moment, in kg / h; It indicates the feed flow rate of the concentrator at t0 seconds backward from the current moment; t0 indicates the time required for the coal sludge flocs to settle to the bottom; It indicates the actual value of the dosage at t0 seconds after the current moment, in L / min. It indicates the setting value of the dosage at t0 seconds backward from the current moment, in L / min.

[0020] Furthermore, the total settled coal slime flow rate settled to the bottom of the concentrator at the current moment is calculated as follows:

[0021]

[0022] Among them, W sed It indicates the total coal slime flow rate that can settle coal slime particles and flocs to the bottom at the current moment, in kg / h.

[0023] Furthermore, the flow rate M of the monomeric coal slime that cannot settle after the initial addition of the drug and enters the settling coal slime after flocculation is RSS It is expressed as:

[0024]

[0025] Among them, t a Indicates the current dosing operation time of the concentrator, in seconds; It indicates the amount of suspended coal slime that settles from the concentrator per second after adding chemicals; M TSS,N It indicates the accumulated suspended fine mud amount in the concentrator when the dosing starts, in kg.

[0026] Furthermore, the cumulative amount of monomeric coal slime that cannot settle when no chemical is added to the concentrator at the current moment also includes the cumulative amount of suspended coal slime with a particle size of 2 to 3 after the concentrator stops adding chemical, wherein the cumulative amount of monomeric coal slime that cannot settle when no chemical is added M TSS It is expressed as:

[0027]

[0028] Among them, M RSS,Y Indicates the amount of suspended fine mud remaining in the concentrator when dosing is stopped, in kg; W in,0 Indicates the flow rate of the concentrator feed at the current moment; C in,0 Indicates the solid concentration of the concentrator feed at the current moment, in g / L; p x,0 It indicates the percentage of particles with particle size x in the concentrator feed at the current moment in the total solid matter; Δt indicates the time step, in seconds.

[0029] Furthermore, the total mass M of the mud at the bottom of the thickener is obtained according to the total settled coal slime flow rate, the accumulated suspended coal slime amount and the mud discharge flow rate of the underflow pump at the current moment. bot , which is expressed as:

[0030]

[0031] Among them, M bot,-1 Indicates the total mass of the sediment at the bottom of the thickener in the last second, C bot Indicates the historical average sludge concentration of the thickener underflow, in g / L; K indicates the on / off status of the underflow pump, with on being 1 and off being 0; W bot Indicates the sludge discharge flow rate of the thickener underflow pump, in m 3 / h,W seds It indicates the total flow rate of coal slime that has settled to the bottom of the concentrator at the current moment, in kg / s.

[0032] Furthermore, the total flow rate of coal slime settled to the bottom of the concentrator at the current moment and the accumulated amount of suspended coal slime are used to obtain the total flow rate of coal slime settled to the bottom of the concentrator at the current moment W: seds , expressed as:

[0033] W seds =(W sed +M TSS ) / 3600,

[0034] Among them, W sed It indicates the total coal slime flow rate of settleable coal slime particles and flocs settling to the bottom at the current moment, in kg / h.

[0035] Furthermore, the bottom flow concentration is predicted based on the total mass of the bottom sludge of the concentrator at the current moment, and the bottom flow predicted concentration C′ bot It is expressed as:

[0036]

[0037] Among them, M bot,av Indicates the historical average of the total amount of sediment at the bottom of the thickener; C bot,av It indicates the historical average concentration of the thickener bottom flow sludge, in g / L.

[0038] The present invention also includes a coal slime thickener underflow concentration prediction system, comprising:

[0039] A data acquisition module is used to acquire historical feed data and dosing data of the concentrator; the dosing data includes the actual value and set value of the dosing amount, and the feed data includes the flow rate of the concentrator feed and the percentage of particles of different particle sizes in the feed to the total solids;

[0040] The prediction module is used to obtain the total mass of the bottom sludge of the concentrator at the current moment according to the historical feed data and dosing data of the concentrator; and to predict the underflow concentration according to the total mass of the bottom sludge of the concentrator at the current moment;

[0041] Wherein, the total mass of the bottom sludge of the concentrator at the current moment is obtained according to the historical feed data and dosing data of the concentrator, including:

[0042] The total settled coal slime flow calculation unit is used to obtain the amount of coal slime settled to the bottom in the form of monomers and the amount of coal slime settled to the bottom in the form of flocs according to the historical feeding data and dosing data of the concentrator, and determine the total settled coal slime flow settled to the bottom of the concentrator at the current moment; the amount of coal slime settled to the bottom in the form of monomers is determined by the flow rate of the concentrator feed and the percentage of particles of the particle size grade in the feed to the total solids; the amount of coal slime settled to the bottom in the form of flocs is determined by the ratio of the actual value of the dosing amount to the set value;

[0043] The cumulative suspended coal slime amount calculation unit is used to obtain the cumulative amount of suspended coal slime in the concentrator at the current moment according to the cumulative amount of monomer coal slime that cannot settle when no chemical is added in the concentrator at the current moment and the flow rate of monomer coal slime that cannot settle after the start of chemical addition and enters the settled coal slime after flocculation;

[0044] The total mass calculation unit of the sludge is used to obtain the total mass of the sludge at the bottom of the concentrator according to the total settled coal sludge flow rate settled to the bottom of the concentrator at the current moment, the accumulated suspended coal sludge amount and the mud discharge flow rate of the underflow pump.

[0045] The present invention also includes a computer device for predicting the underflow concentration of a coal slime thickener, comprising: a memory, a processor, and a computer program stored in the memory, wherein the processor implements the steps of the method for predicting the underflow concentration of a coal slime thickener when executing the computer program.

[0046] The present invention provides a method, system and device for predicting underflow concentration of a coal slime thickener, which has the following features:

[0047] Beneficial effects:

[0048] The present invention obtains the amount of coal slime settled to the bottom in the form of monomers and the amount of coal slime settled to the bottom in the form of flocs according to the feed concentration and the dosing conditions of the concentrator system, and calculates the amount of suspended coal slime accumulated in the concentrator according to the accumulated amount of monomer coal slime that cannot be settled when no drug is added in the current concentrator and the flow rate of the monomer coal slime that cannot be settled after the start of dosing and enters the settled coal slime after flocculation, and predicts the current underflow concentration through the obtained underflow discharge conditions, which is used to control the underflow discharge time; the method can be used to predict the underflow concentration of the concentrator, and can be used to control the underflow discharge without frequently starting and stopping the underflow concentrator through a trial and error method. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a schematic diagram of the process flow for predicting the underflow concentration of a coal slime thickener in an embodiment of the present invention;

[0050] Figure 2 It is a calculation framework diagram of the underflow concentration prediction process of the coal slime concentrator in an embodiment of the present invention. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present invention will be described clearly and completely 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, rather than all the embodiments.

[0052] The present invention proposes a method for predicting the underflow concentration of a coal slime thickener, which can predict the current underflow concentration according to the feed concentration, flow rate, dosing conditions and underflow discharge conditions of the thickening system, and is used to control the underflow discharge time; when the method is put into use, the underflow concentration prediction module of the thickener and the bottom sludge inventory calculation module of the thickener operate independently of each other, and the variable values ​​are transmitted and shared in real time; the following simplified assumptions are made:

[0053] (1) Coal sludge with a particle size of 1 (<45 microns) will flow out of the system with overflow water without adding chemicals and will not be counted when no chemicals are added;

[0054] (2) The sedimentation time of coal slime with particle size of 2-3 (45-125 microns) should be more than 40 minutes, and the non-settling coal slime monomer should be included when no chemical is added;

[0055] (3) Coal slime with a particle size of 3-6 (>125 microns) can be regarded as settleable coal slime.

[0056] like Figure 1 , Figure 2 As shown, Figure 2 ①, ②, and ③ are the same connecting line; the method specifically comprises the following steps:

[0057] S1. Calculate the current sludge inventory at the bottom of the thickener, once every Δt, where the value range of Δt is 10 to 30 seconds. The purpose is to reduce the frequency of access to the database while ensuring that the data error is not large.

[0058] S1.1. Read the historical feed and dosing data to calculate the instantaneous feed flow rate of the settleable coal slime monomers or flocculants currently settled to the bottom when they enter the coal slime thickener.

[0059] The settleable coal slime includes settleable coal slime monomer and floccules. Whether floccules are formed when feeding and the proportion of coal slime formed floccules are determined by the ratio of the actual dosage and the set dosage. Sure.

[0060] For a single particle of size x, the current amount of coal slime sinking to the bottom is the amount of coal slime particles of this size that have not been flocculated into flocs, and its flow rate is the current moment t x (The time required for the monomer with particle size x to settle to the bottom of the concentrator) seconds. The total amount of x-particle size slime in the feed minus the part that is flocculated into floccules is expressed as:

[0061]

[0062] in, Indicates the current time backward t x The flow rate of the concentrator feed in seconds, in m 3 / h;t x W represents the settling time required for the coal slime particles or flocs with particle size x to settle to the bottom in the thickener; sed,x It indicates the flow rate of coal slime monomer particles or flocs with particle size x at the current moment, which settles to the bottom, in kg / h; Indicates the current time backward t x The percentage of particles of size class x in the feed to the concentrator in the total solids at 1 second; Indicates the current time backward t x The actual value of the dosage per second, in L / min; Indicates the current time backward t x The dosage setting value at 1 second, the unit is L / min.

[0063] For flocs, the amount of coal slime that settles to the bottom in the form of flocs is expressed as:

[0064]

[0065] Among them, W sed,0 It indicates the flow rate of coal sludge that the floccules settle to the bottom at the current moment, in kg / h; It indicates the feed flow rate of the concentrator at t0 seconds backward from the current moment; t0 indicates the time required for the coal sludge flocs to settle to the bottom; It indicates the actual value of the dosage at t0 seconds after the current moment, in L / min; It indicates the setting value of the dosage at t0 seconds backward from the current moment, in L / min.

[0066] The total settling slime flow at the current moment is the sum of the two:

[0067]

[0068] Among them, W sedIt indicates the total coal slime flow rate of settleable coal slime particles and flocs settling to the bottom at the current moment, in kg / h.

[0069] S1.2. Calculate the impact of the suspended coal slime accumulated in the thickening system (mainly the monomeric coal slime that cannot settle without adding chemicals, which is suspended and accumulated in the thickening system without adding chemicals during feeding, but will settle to the bottom after the thickening system is started and added) on the bottom flow sludge flow.

[0070] When the system stops adding drugs (changes from adding drugs to not adding drugs), the system enters the state of suspended coal slime accumulation and starts to run without adding drugs; the accumulated suspended mud volume is the accumulated volume of particle size 2-3 (45-125 microns) after starting without adding drugs, which is expressed as:

[0071]

[0072] Among them, M TSS Indicates the amount of suspended fine mud accumulated in the concentrator, kg; M RSS,Y Indicates the amount of suspended fine mud remaining in the concentrator when dosing is stopped, kg; W in,0 Indicates the flow rate of the concentrator feed at the current moment; C in,0 Indicates the solid concentration of the concentrator feed at the current moment, g / L; p x,0 It indicates the percentage of particles with size x in the concentrator feed at the current moment in the total solid matter; Δt indicates the time step, s.

[0073] When the system starts to add drugs (from no drug addition to drug addition), the system enters the state of emptying the accumulated mud volume, and the drug addition operation timing starts. According to experience, the accumulated mud volume in the system can be emptied after adding drugs for 1 hour. Therefore, the flow rate from suspended coal mud to settled coal mud after adding drugs is M TSS / 3600. The amount of suspended coal slime remaining in the system at a certain time point within 1 hour is expressed as:

[0074]

[0075] Among them, t a Indicates the current dosing operation time of the concentrator, in seconds; It indicates the amount of suspended coal slime that settles from the concentrator per second after adding chemicals; M TSS,N It indicates the accumulated suspended fine mud amount in the concentrator when the dosing starts, in kg.

[0076] Total coal slime flow rate that settles to the bottom at the current moment:

[0077] W seds =(W sed +N TSS ) / 3600.

[0078] Among them, W sedsIt indicates the total flow rate of coal slime that has settled to the bottom at the current moment, in kg / s; W sed It indicates the total coal slime flow rate of settleable coal slime particles and flocs settling to the bottom at the current moment, in kg / h.

[0079] S2. Prediction of underflow slime concentration.

[0080] S2.1. Calculate the total mass of mud at the bottom of the thickener, which is the current total mud storage + the current total flow of coal mud that has settled to the bottom - the bottom flow mud discharge flow It is expressed as:

[0081]

[0082] Among them, M bot,-1 Indicates the total mass of the bottom sediment in the system in the last second, C bot Indicates the historical average sludge concentration of the thickener underflow, g / L; K indicates the on / off status of the underflow pump, 1 for on and 0 for off; W bot Indicates the sludge discharge flow rate of the thickener underflow pump, m 3 / h.

[0083] S2.2. Calculate the predicted underflow concentration:

[0084]

[0085] Among them, M bot,av Indicates the historical average of the total amount of sediment at the bottom of the thickener; C bot,av It indicates the historical average concentration of the thickener bottom flow sludge, in g / L.

[0086] In the present invention, the variable p x Refers to the proportion of particles of each size class in the feed of the concentrator, which is detected by the online particle size analyzer and stored in the historical database and read when needed; in the case of little fluctuation in coal quality or no online particle size detector is installed, offline test data can be used instead, which does not change with time; C in,t , The variables are detected by online instruments and stored in the historical database, and read when needed.

[0087] It has been calculated that particles of all sizes in the concentrator feed with a diameter greater than 74 microns are in the transition zone when they are freely settling. The transition zone settling formula can be used to calculate their free settling speed:

[0088]

[0089] The natural settling speed of each particle size fraction in the thickening tank:

[0090]

[0091] Among them, t x After the first calculation, it is used as a constant; u x Indicates the sedimentation velocity of coal slime particles or flocs of particle size x (=0-6) in the concentrator, m / s; u t,x represents the final free settling velocity of coal slime particles or flocs of particle size x (=0-6), m / s; D represents the concentrator diameter, m; H represents the average height of the concentrator tank, m; ρ s Indicates the average density of coal slime particles, kg / m 3 ;d x It represents the average diameter of coal slime particles or flocs of particle size grade x (=0~6), taking the arithmetic mean of the upper and lower limits of the particle size range. When x=0, the floc particle size d0=0.001, m.

[0092] Based on the same inventive concept, the present invention also includes a coal slime thickener underflow concentration prediction system, comprising:

[0093] The data acquisition module is used to obtain the historical feed data and dosing data of the concentrator; the dosing data includes the actual value and set value of the dosing amount; the feed data includes the flow rate of the concentrator feed and the percentage of particles of different particle sizes in the feed to the total solid matter.

[0094] The prediction module is used to obtain the total mass of the bottom sludge of the concentrator at the current moment according to the historical feed data and dosing data of the concentrator; and predict the underflow concentration according to the total mass of the bottom sludge of the concentrator at the current moment.

[0095] Among them, according to the historical feed data and dosing data of the concentrator, the total mass of the bottom sludge of the concentrator at the current moment is obtained, including:

[0096] The total settled coal slime flow calculation unit is used to obtain the amount of coal slime settled to the bottom in the form of monomers and the amount of coal slime settled to the bottom in the form of flocs according to the historical feeding data and dosing data of the concentrator, and determine the total settled coal slime flow settled to the bottom of the concentrator at the current moment; the amount of coal slime settled to the bottom in the form of monomers is determined by the flow rate of the concentrator feed and the percentage of particles of the particle size grade in the feed to the total solids; the amount of coal slime settled to the bottom in the form of flocs is determined by the ratio of the actual value of the dosing amount to the set value.

[0097] The cumulative suspended coal slime amount calculation unit is used to obtain the cumulative amount of suspended coal slime in the concentrator at the current moment according to the cumulative amount of monomer coal slime that cannot settle when no chemical is added in the concentrator at the current moment and the flow rate of monomer coal slime that cannot settle after the start of chemical addition and enters the settled coal slime after flocculation.

[0098] The total mass calculation unit of the sludge is used to obtain the total mass of the sludge at the bottom of the concentrator according to the total settled coal sludge flow rate settled to the bottom of the concentrator at the current moment, the accumulated suspended coal sludge amount and the mud discharge flow rate of the underflow pump.

[0099] The present invention also includes a computer device for predicting the underflow concentration of a coal slime thickener, including: a memory, a processor, and a computer program stored in the memory. When the processor executes the computer program, the steps of the method for predicting the underflow concentration of a coal slime thickener are implemented.

[0100] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for predicting underflow concentration of a coal slime thickener, characterized in that: The following steps are involved: Obtaining historical feed data and dosing data of the concentrator; the dosing data includes the actual value and set value of the dosing amount, and the feed data includes the flow rate of the concentrator feed and the percentage of particles of different particle sizes in the feed to the total solids; According to the historical feed data and dosing data of the concentrator, the total mass of the bottom sludge of the concentrator at the current moment is obtained; according to the total mass of the bottom sludge of the concentrator at the current moment, the underflow concentration is predicted; The method of obtaining the total mass of the bottom sludge of the concentrator at the current moment according to the historical feed data and dosing data of the concentrator specifically includes the following steps: According to the historical feed data and dosing data of the concentrator, the amount of coal slime settled to the bottom in the form of monomers and the amount of coal slime settled to the bottom in the form of flocs are obtained respectively, and the total settled coal slime flow rate settled to the bottom of the concentrator at the current moment is determined; the amount of coal slime settled to the bottom in the form of monomers is determined by the flow rate of the concentrator feed and the percentage of particles of the particle size grade in the feed to the total solids; the amount of coal slime settled to the bottom in the form of flocs is determined by the ratio of the actual value of the dosing amount to the set value; According to the accumulated amount of monomeric coal slime that cannot settle in the concentrator without adding chemicals at the current moment and the flow rate of monomeric coal slime that cannot settle after starting to add chemicals and enters the settled coal slime after flocculation, the accumulated amount of suspended coal slime in the concentrator at the current moment is obtained; The total mass of the sludge at the bottom of the concentrator is obtained according to the total settled coal slime flow rate settling to the bottom of the concentrator at the current moment, the accumulated suspended coal slime amount and the mud discharge flow rate of the underflow pump.

2. A method for predicting underflow concentration of a coal slime thickener according to claim 1, characterized in that: The amount of coal slime that settles to the bottom in the form of monomers is expressed as: in, Indicates the current time backward t x The flow rate of the concentrator feed in seconds, in m 3 / h;t x W represents the settling time required for the coal slime particles or flocs with particle size x to settle to the bottom in the thickener; sed,x It indicates the flow rate of coal slime monomer particles or flocs with particle size x at the current moment, which settles to the bottom, in kg / h; Indicates the current time backward t x The percentage of particles of size class x in the total solids in the feed to the concentrator at 1 second; Indicates the current time backward t x The actual value of the dosage at seconds, in L / min; Indicates the current time backward t x The setting value of the dosage at 1 second, in L / min; The amount of coal slime settled to the bottom in the form of flocs is expressed as: Among them, W sed,0 It indicates the flow rate of coal sludge that the floccules settle to the bottom at the current moment, in kg / h; It indicates the feed flow rate of the concentrator at t0 seconds backward from the current moment; t0 indicates the time required for the coal sludge flocs to settle to the bottom; It indicates the actual value of the dosage at t0 seconds after the current moment, in L / min. It indicates the setting value of the dosage at t0 seconds backward from the current moment, in L / min.

3. A method for predicting underflow concentration of a coal slime thickener according to claim 2, characterized in that: The total sedimentation slime flow rate that settles to the bottom of the concentrator at the current moment is calculated as follows: Among them, W sed It indicates the total coal slime flow rate that can settle coal slime particles and flocs to the bottom at the current moment, in kg / h.

4. A method for predicting underflow concentration of a coal slime thickener according to claim 3, characterized in that: The flow rate M of the monomeric coal slime that cannot settle after the initial addition of the drug and then enters the settling coal slime after flocculation RSS It is expressed as: Among them, t a Indicates the current dosing operation time of the concentrator, in seconds; It indicates the amount of suspended coal slime that settles from the concentrator per second after adding chemicals; M TSS,N It indicates the accumulated suspended fine mud amount in the concentrator when the dosing starts, in kg.

5. A method for predicting underflow concentration of a coal slime thickener according to claim 4, characterized in that: The cumulative amount of monomeric coal slime that cannot settle when no drug is added to the concentrator at the current moment also includes the cumulative amount of suspended coal slime with a particle size of 2 to 3 after the drug addition is stopped in the concentrator, wherein the cumulative amount of monomeric coal slime that cannot settle when no drug is added M TSS It is expressed as: Among them, M RSS,Y Indicates the amount of suspended fine mud remaining in the concentrator when dosing is stopped, in kg; W in,0 Indicates the flow rate of the concentrator feed at the current moment; C in,0 Indicates the solid concentration of the concentrator feed at the current moment, in g / L; p x,0 It indicates the percentage of particles with particle size x in the concentrator feed at the current moment in the total solid matter; Δt indicates the time step, in seconds.

6. A method for predicting underflow concentration of a coal slime thickener according to claim 5, characterized in that: The total mass M of the mud at the bottom of the concentrator is obtained according to the total settled coal mud flow rate, the accumulated suspended coal mud volume and the mud discharge flow rate of the underflow pump at the current moment. bot , which is expressed as: Among them, M bot,-1 Indicates the total mass of the sediment at the bottom of the thickener in the last second, C bot It indicates the historical average sludge concentration of the thickener underflow, in g / L; K indicates the start / stop status of the underflow pump; W bot Indicates the sludge discharge flow rate of the thickener underflow pump, in m 3 / h,W seds It indicates the total flow rate of coal slime that has settled to the bottom of the concentrator at the current moment, in kg / s.

7. A method for predicting underflow concentration of a coal slime thickener according to claim 6, characterized in that: The total flow rate of coal slime settled to the bottom of the concentrator at the current moment and the accumulated amount of suspended coal slime are used to obtain the total flow rate W of coal slime settled to the bottom of the concentrator at the current moment. seds , expressed as: W seds =(W sed +M TSS ) / 3600, Among them, W sed It indicates the total coal slime flow rate of settleable coal slime particles and flocs settling to the bottom at the current moment, in kg / h.

8. A method for predicting underflow concentration of a coal slime thickener according to claim 7, characterized in that: The bottom flow concentration is predicted based on the total mass of the bottom sludge of the concentrator at the current moment, and the predicted bottom flow concentration C′ bot It is expressed as: Among them, M bot,av Indicates the historical average of the total amount of sediment at the bottom of the thickener; C bot,av It indicates the historical average concentration of the thickener bottom flow sludge, in g / L.

9. A coal slime thickener underflow concentration prediction system, characterized in that: include: A data acquisition module is used to acquire historical feed data and dosing data of the concentrator; the dosing data includes the actual value and set value of the dosing amount, and the feed data includes the flow rate of the concentrator feed and the percentage of particles of different particle sizes in the feed to the total solids; The prediction module is used to obtain the total mass of the bottom sludge of the concentrator at the current moment according to the historical feed data and dosing data of the concentrator; and to predict the underflow concentration according to the total mass of the bottom sludge of the concentrator at the current moment; Wherein, the total mass of the bottom sludge of the concentrator at the current moment is obtained according to the historical feed data and dosing data of the concentrator, including: The total settled coal slime flow calculation unit is used to obtain the amount of coal slime settled to the bottom in the form of monomers and the amount of coal slime settled to the bottom in the form of flocs according to the historical feeding data and dosing data of the concentrator, and determine the total settled coal slime flow settled to the bottom of the concentrator at the current moment; the amount of coal slime settled to the bottom in the form of monomers is determined by the flow rate of the concentrator feed and the percentage of particles of the particle size grade in the feed to the total solids; the amount of coal slime settled to the bottom in the form of flocs is determined by the ratio of the actual value of the dosing amount to the set value; The cumulative suspended coal slime amount calculation unit is used to obtain the cumulative amount of suspended coal slime in the concentrator at the current moment according to the cumulative amount of monomer coal slime that cannot settle when no chemical is added in the concentrator at the current moment and the flow rate of monomer coal slime that cannot settle after the start of chemical addition and enters the settled coal slime after flocculation; The total mass calculation unit of the sludge is used to obtain the total mass of the sludge at the bottom of the concentrator according to the total settled coal sludge flow rate settled to the bottom of the concentrator at the current moment, the accumulated suspended coal sludge amount and the mud discharge flow rate of the underflow pump.

10. A computer device for predicting underflow concentration of a coal slime thickener, characterized in that: include: A memory, a processor and a computer program stored in the memory, wherein the processor implements the steps of the method for predicting the underflow concentration of a coal slime thickener according to any one of claims 1 to 8 when executing the computer program.

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