A method and computer equipment for integrating a chemical dosing system and a filter press system in a coal preparation plant.

Abstract

This invention relates to the field of coal washing and processing technology, and discloses a method and computer equipment for integrating a chemical dosing system and a filter press system in a coal preparation plant. The method includes the following steps: the chemical dosing system calculates the target value of the flocculant based on the raw coal quantity and process parameters, and generates the real-time flocculant flow rate by combining turbidity feedback correction. Key parameters are introduced, and the filter press system monitors the concentration pressure, controls operation, and generates an operating sequence. During the low-pressure stage, a follow-up strategy is implemented, using the real-time flocculant flow rate and critical proportionality constant to calculate the target flow rate of the filter aid and adjust the frequency. During the non-low-pressure stage, a feedback strategy is implemented, collecting the effective filter press feeding time according to the operating sequence, comparing it with the standard time, and then performing reverse feedback adjustment to correct the filter aid pump frequency. This invention overcomes the impact of process lag by constructing a segmented closed-loop control logic across systems, achieving dynamic and precise control of the chemicals, improving filter press efficiency and reducing costs while ensuring concentration effects.

Description

Technical Field

[0001] This invention relates to the field of coal washing and processing technology, specifically to a method and computer equipment for integrating a chemical dosing system and a filter press system in a coal preparation plant. Background Technology

[0002] Coal slurry water treatment is a crucial step in the coal preparation plant's production process, primarily responsible for closed-loop circulation of wash water and coal slurry recovery. This process exhibits typical nonlinear and strongly coupled characteristics, involving a series of continuous operations such as concentration, sedimentation, and pressure filtration dewatering of the feed coal slurry water, resulting in a relatively long process flow. When influencing factors such as feed concentration, particle size distribution, or flow rate change, the system adjustment process often exhibits significant time lags and substantial inertia, posing challenges to the stable control of the coal slurry water treatment system.

[0003] In existing coal slurry water treatment processes, the dosing system is used to improve the settling and dewatering characteristics of coal slurry, while the filter press system is used to achieve final solid-liquid separation. With the development of intelligent technologies in the coal preparation industry, significant progress has been made in the independent control technologies for these two systems. For example, in the dosing stage, existing technologies typically employ a combination of feedforward and feedback strategies. Feedforward feeding is based on the raw coal throughput and the optimal chemical consumption determined in the laboratory, while the turbidity of the thickener overflow or the slurry layer thickness is used as feedback signals to adjust the flocculant dosage. In the filter press stage, existing technologies mostly employ automatic queuing control logic based on the bottom pressure of the thickener. The number of filter presses activated is determined by the pressure threshold, and automatic control of the filter press cycle and fault interlocking are achieved through filtrate flow meters or displacement sensors.

[0004] However, existing control models typically treat the dosing system and the filter press system as two independent control units, lacking deep integration at the system level. Current dosing control strategies primarily aim to ensure the overflow turbidity of the thickener meets requirements, with filter aids and flocculants usually added in fixed proportions or based solely on reagent formulations determined through laboratory static tests. This control approach fails to incorporate the actual operating efficiency of the downstream filter press (such as feeding time and filter cake moisture content) as effective feedback variables into the front-end dosing control logic. When the properties of the coal slurry fluctuate, the lack of a cross-system linkage feedback mechanism means that relying solely on turbidity feedback cannot perceive the impact of reagent ratios on subsequent dewatering performance, making it difficult for the system to simultaneously ensure sedimentation and filter press efficiency. Furthermore, existing control logic struggles to overcome interference caused by large process lags and lacks targeted, tiered control strategies for different operating conditions such as low and high pressure. This often results in excessive reagent addition or unnecessary extensions of the filter press cycle, limiting the improvement of unmanned operation levels and further reduction of operating costs in the coal slurry water treatment process of coal preparation plants. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method and computer equipment for integrating a chemical dosing system and a filter press system in a coal preparation plant. This solves the problem in existing technologies where the control logic of the chemical dosing and filter press processes is isolated from each other, making it impossible to use back-end filter press data to guide front-end chemical dosing, resulting in poor synergistic effects of the chemicals and difficulty in adapting to large lag fluctuations in operating conditions.

[0006] The first aspect of this invention provides a method for integrating a chemical dosing system and a filter press system in a coal preparation plant, comprising: The dosing system performs feedforward calculations based on real-time collected raw coal quantity and preset process parameters to obtain the target value of flocculant flow rate.

[0007] The dosing system performs dosing control based on the target flocculant flow rate and combines turbidity feedback to correct the output frequency, thereby generating the real-time flocculant flow rate.

[0008] The dosing system incorporates preset pressure thresholds, critical proportional constants, and standard filter press feeding times. The filter press system monitors the concentration pressure of the thickener, controls the filter press's operating status based on the concentration pressure, and generates an operating sequence.

[0009] The dosing system determines whether the current operating condition is a low-pressure stage or a non-low-pressure stage based on the comparison between the concentration pressure and the pressure threshold.

[0010] During the low-pressure phase, the dosing system executes a follow-up strategy based on a critical proportioning constant, using the real-time flow rate of the flocculant and the critical proportioning constant to calculate the target flow rate of the filter aid and adjust the pumping frequency of the filter aid metering pump.

[0011] During the non-low pressure phase, the dosing system implements a feedback strategy based on the effective filter press feeding time. It compares the effective filter press feeding time collected by the filter press system according to the operating sequence with the standard filter press feeding time and performs reverse feedback adjustment to correct the filter aid pump frequency.

[0012] Further, step S1 specifically includes: the dosing system controls the raw coal belt scale to collect the raw coal quantity, and calculates the hourly dry coal slime quantity in conjunction with the preset coal slime product ratio as a process parameter. The dosing system uses a reagent addition algorithm to calculate the target flocculant flow rate based on the hourly dry coal slime quantity, the optimal reagent consumption per ton of dry coal slime determined by coal slime water settling test data stored in the internal database as a process parameter, and the flocculant concentration, following the principle of solute conservation. The coal slime product ratio is a pre-set value based on the process design parameters of the coal preparation plant or statistical analysis of historical production data.

[0013] Further, step S2 specifically includes: the dosing system converts the target flocculant flow rate into a control command based on a preset flocculant flow frequency characteristic curve to adjust the output frequency of the flocculant metering pump. This preset flocculant flow frequency characteristic curve is pre-drawn and stored based on the mechanical characteristics of the flocculant metering pump and on-site calibration experiments. The dosing system uses a turbidity meter to monitor the turbidity of the overflow water from the thickener in real time. When the turbidity exceeds a preset turbidity threshold, the output frequency is gradually adjusted according to a preset flocculant adjustment step size until the turbidity decreases below the turbidity threshold.

[0014] After feedforward calculation and turbidity feedback correction stabilization, the flow rate corresponding to the current actual operating frequency of the flocculant metering pump is determined as the real-time flocculant flow rate. Among them, the turbidity threshold is a value preset according to the water quality process requirements of the coal preparation plant's circulating water; the preset flocculant adjustment step size is a frequency increment or decrement value preset according to the lag time and adjustment accuracy of the flocculant metering pump.

[0015] Furthermore, the specific sources for setting the parameters in step S3 include: the dosing system analyzing historical data on filter press feeding times under different concentration pressures, determining the physical inflection point where the filter press feeding time changes from a discrete, highly fluctuating state to a convergent, stable, low-value state as the pressure threshold value; the dosing system determining the dosage ratio point at which the filter aid changes from inhibiting coal slurry sedimentation to promoting or not affecting sedimentation based on synergistic sedimentation tests of filter aid and flocculant, setting this as the critical proportional constant; and the dosing system calculating the target value for the filter press cycle that balances filter press efficiency and economy based on the target production capacity and the upper limit of the ideal dewatering rate of coal slurry under the corresponding operating conditions, setting this as the standard filter press feeding time.

[0016] Further, step S4 specifically includes: the filter press system monitors the concentration pressure in real time using a pressure sensor. The filter press system compares the concentration pressure with a preset pressure range threshold to determine the specific pressure range in which the concentration pressure is located. Based on the preset mapping relationship between the pressure range and the number of operating units, it outputs an operation number command to drive the corresponding number of filter presses into operation. The filter press system records the start-up time of each filter press in operation in real time, and sorts all currently operating filter presses according to the order of their start-up times, generating a current equipment working list, which is defined as the operating sequence. The pressure range threshold is a preset value based on the equipment load capacity corresponding to different pressure ranges in the filter press automatic queuing control logic.

[0017] Further, step S5 specifically includes: the dosing system calculates the target flow rate of the filter aid using the filter aid flow rate formula, and determines the product of the real-time flow rate of the flocculant and the critical proportionality constant as the target flow rate of the filter aid. Based on a preset filter aid flow-frequency characteristic curve, the dosing system generates a physical control frequency corresponding to the target flow rate of the filter aid, and sends the physical control frequency to the variable frequency drive unit of the filter aid metering pump via command, directly adjusting the frequency of the filter aid pump. The preset filter aid flow-frequency characteristic curve is pre-drawn and stored based on the mechanical characteristics of the filter aid metering pump and on-site calibration experiments.

[0018] Furthermore, the acquisition of effective filter press feeding time in step S6 specifically includes: the filter press system calls the running sequence, skips the first-ranked filter press in the running sequence, and locks the second-ranked filter press as the current sampling object, so as to eliminate data deviations caused by pipeline residue or excessive concentration in the first filter press that is started. The filter press system collects the time span from the issuance of the start feeding command to the issuance of the end feeding command for the second-ranked filter press, defines it as the effective filter press feeding time, and transmits it to the dosing system.

[0019] Further, the reverse feedback adjustment in step S6 specifically includes: the dosing system uses the received effective filter press feeding time and standard filter press feeding time as input variables, and applies a frequency adjustment formula to obtain the adjustment direction of the filter aid pump frequency. If the result of the frequency adjustment formula corresponds to a decrease command, the dosing system gradually decreases the filter aid pump frequency according to a preset filter aid adjustment step size; if the result of the frequency adjustment formula corresponds to an increase command, the dosing system gradually increases the filter aid pump frequency according to a preset filter aid adjustment step size. The preset filter aid adjustment step size is a frequency increment or decrement value pre-set based on the adjustment accuracy of the filter aid metering pump.

[0020] Furthermore, the logical relationship defined by the frequency adjustment formula is as follows: when the effective filter press feeding time is not greater than the standard filter press feeding time, it is determined that the filter aid has been added in excess or the target has been met, and the change in the filter aid pump frequency is defined as a negative value, corresponding to the execution of a decrease command; when the effective filter press feeding time is greater than the standard filter press feeding time, it is determined that the filter aid has been added in insufficient quantity, and the change in the filter aid pump frequency is defined as a positive value, corresponding to the execution of an increase command.

[0021] Furthermore, step S6 also includes: after the dosing system performs an adjustment action on the filter aid pump frequency, it starts a hold timer. During the preset time period of the hold timer, the dosing system maintains the current frequency, ignores fluctuations in the filter press data, and waits for the adjusted chemical effect to be transmitted to the filter press. This continues until a new effective filter press feeding time is generated, at which point the next round of feedback adjustment is performed. The preset time period of the hold timer is set based on the material residence time calculated from the volume of the thickener and the underflow rate.

[0022] A second aspect of the present invention provides a computer device, including a processor, a communication interface, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements a method for integrating a coal preparation plant dosing system and a filter press system as described in the first aspect above.

[0023] This invention provides a method and computer equipment for integrating a chemical dosing system and a filter press system in a coal preparation plant. It offers the following advantages: 1. This invention achieves dynamic and precise control of the dosage of flocculants by establishing data interaction between the dosing system and the filter press system. It can calculate the flocculant demand in real time based on changes in raw coal quantity and quality, and correct the dosage of filter aid by using the reverse feedback mechanism of filter press feeding time. This solves the problem of excessive or insufficient dosage caused by traditional manual experience-based dosing. It not only reduces the unit consumption of flocculants and filter aids, but also shortens the single operation time of the filter press feed pump due to the improvement of filter press efficiency, thereby reducing power consumption and equipment spare parts wear, and effectively reducing the operating cost of coal preparation plants.

[0024] 2. This invention adopts a segmented fusion control strategy based on concentration pressure, which overcomes the problems of large lag and nonlinear coupling between the concentration and filtration stages. In the low-pressure stage, a following strategy is adopted to ensure the bottom line of operation and prevent control divergence. In the non-low-pressure stage, a reverse feedback strategy is adopted to ensure that the filter press operates in the optimal dewatering range. This graded control mechanism improves the concentration of the underflow and the solids yield, shortens the filter press feeding cycle, and improves the overall processing capacity of the system and the response speed to fluctuations in operating conditions.

[0025] 3. This invention achieves unmanned operation from chemical preparation to filter press dewatering by constructing a closed-loop automatic control logic for the entire process. It replaces traditional manual inspection and adjustment by automatically collecting and analyzing parameters such as turbidity, pressure and time, optimizes the allocation of personnel and reduces labor intensity. At the same time, the precise control of the standard filter press feeding time can stabilize the moisture content of the filter cake, reduce product quality fluctuations, and improve the intelligent level of coal preparation plant production management and the safety and reliability of the system. Attached Figure Description

[0026] Figure 1 This is a flowchart of a method for integrating a chemical dosing system and a filter press system in a coal preparation plant according to the present invention; Figure 2 This is a flowchart of the low-pressure stage system fusion control of the present invention; Figure 3 This is a flowchart of the system fusion control for the non-low pressure stage of the present invention. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Please see the appendix Figure 1 This invention provides a method for integrating a chemical dosing system and a filter press system in a coal preparation plant. This method relies on data interaction between the chemical dosing system and the filter press system.

[0029] The dosing system includes a raw coal belt scale, a dosing device, a flocculant metering pump, a filter aid metering pump, a turbidity meter installed at the overflow weir of the thickener, and an interface meter installed at the bottom of the thickener.

[0030] The filter press system includes a thickener, a pressure sensor installed at the bottom of the thickener, a filter press group consisting of multiple filter presses, a transfer pump, and buffer facilities.

[0031] The dosing system and the filter press system are connected via computer equipment to establish an industrial Ethernet or fieldbus communication connection, so as to realize the real-time transmission of data on concentration pressure and filter press feeding time and the issuance of instructions.

[0032] The computer device includes a processor, a communication interface, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements a method for integrating a coal preparation plant dosing system and a filter press system provided in this embodiment. The method specifically includes the following steps: Step S1: Perform basic data acquisition and flocculant target value calculation. The dosing system controls the raw coal belt scale to collect the raw coal quantity and reads the preset coal slime product ratio. The dosing system calculates the hourly dry coal slime quantity based on the raw coal quantity and coal slime product ratio. The dosing system calls the optimal flocculant consumption per ton of dry coal slime determined based on preset coal slime water settling test data from the database, and combines it with the preset reagent concentration, using a reagent addition algorithm to calculate the target flocculant flow rate.

[0033] Step S2: Execute closed-loop control of flocculant dosing. Based on a preset flow frequency characteristic curve, the dosing system converts the target flocculant flow rate obtained in step S1 into a control command, adjusting the output frequency of the flocculant metering pump. The dosing system uses a turbidity meter to monitor turbidity and an interface meter to monitor sludge thickness. When the turbidity exceeds the turbidity threshold, the dosing system adjusts the frequency of the flocculant metering pump according to a step size, thereby generating the real-time flocculant flow rate. This real-time flocculant flow rate serves as the baseline variable for subsequent filter aid control.

[0034] Step S3: Define and set key control parameters. A pressure threshold value is introduced for the dosing system. This value is derived from the analysis of filter press feeding time under different concentration pressures in historical data. The physical inflection point at which the filter press feeding time changes from a discrete, highly fluctuating state to a convergent, stable, low-value state is determined as the pressure threshold value.

[0035] The dosing system incorporates a critical proportionality constant. This value, determined based on coal slurry settling tests and viscosity and pressure filtration tests, sets the point at which the dosage ratio of the filter aid changes from inhibiting coal slurry settling to promoting or not affecting settling as the critical proportionality constant.

[0036] The dosing system incorporates a standard filter press feeding time. This value is calculated based on the target production capacity and the upper limit of the ideal dewatering rate of coal slime under this operating condition, and serves as the target value for the filter press cycle.

[0037] Step S4: Determine the operating status and working condition classification of the filter press. The filter press system uses pressure sensors to monitor the concentration pressure of the thickener. Based on the concentration pressure range, the filter press system controls the number of operating filter presses: shut down when the concentration pressure is less than 0.8 MPa; operate one filter press when the concentration pressure is greater than or equal to 0.8 MPa and less than 1.3 MPa; operate two filter presses when the concentration pressure is greater than or equal to 1.3 MPa and less than 2.0 MPa; and operate three filter presses when the concentration pressure is greater than or equal to 2.0 MPa.

[0038] The filter press system records the start-up time and current working status of each filter press in real time. Based on the order in which the filter presses are started, the system sorts the filter presses currently in operation, generates a list of equipment in operation at the current moment, and defines this list as the running sequence.

[0039] The dosing system acquires the real-time monitoring concentration pressure, compares it with the pressure threshold value set in step S3, determines the current operating condition stage, and triggers subsequent steps based on the current operating condition stage. If the concentration pressure is less than the pressure threshold value, it is determined to be a low-pressure stage; if the concentration pressure is greater than or equal to the pressure threshold value, it is determined to be a non-low-pressure stage.

[0040] Step S5: Execute the fusion control strategy for the low-pressure stage. When the current operating condition is determined to be a low-pressure stage, the dosing system executes a following strategy based on the critical proportionality constant. The dosing system obtains the real-time flocculant flow rate generated in step S2 and the critical proportionality constant set in step S3, and calculates the target flow rate of the filter aid using the filter aid flow rate formula.

[0041] The formula for filter aid flow rate is shown below: ; In the formula: Indicates the target flow rate of the filter aid; Indicates the real-time flow rate of the flocculant; This represents the critical proportionality constant.

[0042] The dosing system directly adjusts the frequency of the filter aid metering pump based on the flow frequency characteristic curve and the target flow rate of the filter aid, so as to achieve the proportional following of the filter aid to the flocculant.

[0043] Step S6: Execute the fusion control strategy for the non-low pressure stage. When the current operating condition is determined to be a non-low pressure stage, the system executes a feedback strategy based on the effective filter press feeding time. The filter press system locks the currently running second filter press according to the operating sequence determined in step S4, collects the filter press feeding time of this equipment, defines it as the effective filter press feeding time, and transmits it to the dosing system.

[0044] The dosing system compares the received effective filter press feeding time with the standard filter press feeding time set in step S3, and applies the frequency adjustment formula to perform reverse feedback adjustment of the filter aid metering pump frequency.

[0045] The frequency adjustment formula is as follows: ; In the formula: This indicates the change in the frequency of the filter aid pump; Indicates the effective filter press feeding time; Indicates the standard filter press feeding time; Indicates the direction of decrease; Indicates the direction of increase; Indicates logical relationships; This indicates the conditional judgment logic.

[0046] The specific adjustment process is as follows: if the effective filter press feeding time is less than the standard filter press feeding time, the dosing system gradually reduces the frequency of the filter aid pump according to the step size; if the effective filter press feeding time is greater than the standard filter press feeding time, the dosing system gradually increases the frequency of the filter aid pump according to the step size.

[0047] During step S1, which involves basic data acquisition and flocculant target value calculation, the dosing system establishes a data interaction link with on-site monitoring equipment to construct a feedforward control model. This process specifically includes the following sub-steps: Step S101: The dosing system acquires the raw coal quantity and calculates the hourly dry coal slime quantity. The dosing system establishes a communication connection with the raw coal belt scale and collects the raw coal quantity data transmitted by the belt scale in real time. The dosing system internally stores a preset coal slime product ratio, which is derived from the process design parameters of the coal preparation plant or statistical analysis of historical production data, representing the mass proportion of raw coal quantity converted into coal slime product. The dosing system multiplies the collected real-time raw coal quantity with the preset coal slime product ratio to calculate the hourly dry coal slime quantity under the current operating conditions. The specific working principle and signal transmission method of the raw coal belt scale are well-known technologies in this field and will not be described in detail here.

[0048] Step S102: The dosing system determines the optimal dosing consumption and concentration per ton of dry coal slime. The dosing system retrieves the dosing regime data stored in its internal database. This dosing regime data is based on coal slime water settling test data conducted according to GB / T 18712-2002 standard. By experimentally determining the settling effect under different coal quality characteristics, the optimal dosing consumption per ton of dry coal slime under corresponding operating conditions was determined. The optimal dosing consumption per ton of dry coal slime characterizes the pure dosage of dosing required to treat a unit mass of dry coal slime. Simultaneously, the dosing system reads the concentration of the prepared flocculant set in the flocculant preparation stage. This parameter reflects the mass fraction or volume concentration of the effective components in the flocculant solution.

[0049] Step S103: The dosing system calculates the target flocculant flow rate. The dosing system uses a dosing algorithm, taking the hourly dry coal slime quantity calculated in step S101, the optimal flocculant consumption per ton of dry coal slime determined in step S102, and the prepared flocculant concentration as input variables. The calculation logic follows the principle of solute conservation, meaning the required mass of pure flocculant equals the product of the flocculant solution flow rate and the prepared flocculant concentration. The dosing system calculates the flocculant solution flow rate required to meet the current coal slime treatment needs and marks this calculation result as the target flocculant flow rate. The target flow rate of this flocculant. This serves as the initial setting basis for the subsequent frequency conversion control of the flocculant metering pump.

[0050] During the execution of step S2, the flocculant dosing closed-loop control, the dosing system dynamically adjusts the flocculant dosage based on feedforward calculations and on-site feedback data. This includes the following sub-steps: Step S201: The dosing system executes feedforward control commands. The dosing system internally stores the flow frequency characteristic curve of the flocculant metering pump. This curve, pre-plotted and stored based on the pump's mechanical characteristics and on-site calibration experiments, characterizes the linear or nonlinear relationship between the pump's output frequency and the flocculant flow rate. The dosing system reads the target flocculant flow rate value obtained in step S1. The corresponding control frequency can be found or calculated based on the current frequency characteristic curve.

[0051] The dosing system sends the frequency command to the frequency converter of the flocculant metering pump via a PLC or DCS interface, driving the flocculant metering pump to operate at that frequency and complete the basic flocculant addition operation. The specific circuit implementation and signal transmission mechanism of the metering pump's frequency converter control are well-known technologies in this field and will not be elaborated upon here.

[0052] Step S202: The dosing system collects and provides feedback monitoring data. The dosing system establishes a communication connection with the turbidity meter installed at the overflow weir of the thickener to acquire real-time turbidity data of the overflow water. This data reflects the quality of the supernatant after thickening and settling. Simultaneously, the dosing system establishes a communication connection with the interface meter installed at the bottom of the thickener to acquire real-time data on the sludge layer thickness inside the thickener. This data reflects the material accumulation status at the bottom of the thickener.

[0053] Step S203: The dosing system executes a feedback adjustment strategy. The dosing system reads a preset turbidity threshold, which is a value pre-set based on the process requirements for circulating water quality in the coal preparation plant or the specific indicator requirements for overflow water in subsequent production stages. The dosing system compares the real-time turbidity collected in step S202 with the turbidity threshold. If the real-time turbidity is less than the turbidity threshold, it indicates that the current dosing amount meets the sedimentation requirements, and the dosing system maintains the output frequency determined in step S201 unchanged.

[0054] If the real-time turbidity is greater than the turbidity threshold, it indicates that the current flocculant dosage is insufficient to allow the coal slime particles to settle sufficiently. The dosing system will then gradually adjust the output frequency of the flocculant metering pump according to a preset step size until the real-time turbidity drops below the turbidity threshold. This step size is a preset frequency increment or decrement value based on the system's lag time and adjustment accuracy to avoid excessive system oscillations.

[0055] Step S204: The dosing system monitors the sludge layer thickness and outputs real-time flow data. The dosing system reads the preset sludge layer thickness threshold, which is a safety limit preset based on the rated mechanical load capacity of the thickener scraper and the effective volume of the thickener tank.

[0056] The dosing system compares the real-time mud layer thickness with a mud layer thickness threshold. If the mud layer thickness exceeds the threshold, the dosing system triggers an alarm signal, prompting operators or the upper control system to take mud removal measures to prevent rake accidents. After the above-mentioned feedforward control and feedback adjustment stabilize, the flow rate corresponding to the current actual operating frequency of the flocculant metering pump is determined as the real-time flocculant flow rate. The dosing system will monitor the real-time flow rate of the flocculant. The data is stored and transmitted to the subsequent low-pressure phase fusion control strategy as baseline input data for calculating the amount of filter aid used.

[0057] When defining and setting key control parameters in step S3, the dosing system determines the pressure threshold, critical proportional constant, and standard filter press feeding time based on statistical analysis of historical operating data, results of joint laboratory tests, and production capacity targets. This process specifically includes the following sub-steps: Step S301: Set the pressure threshold value for the dosing system. The dosing system retrieves and analyzes the correlation data between the concentration pressure, the concentration of the underflow, and the filter press feeding time from historical production data. Table 1 shows detailed data on the underflow concentration and filter press feeding time under different concentration tank pressures.

[0058] Table 1. Details of underflow concentration and filter press feeding time under different thickener pressures.

[0059] Based on the data in Table 1, logical judgment is made as follows: When the concentration pressure is less than 1.3 MPa, the concentration of the concentrated underflow is at a low level, and the corresponding filter press feeding time is extremely large and highly volatile, indicating that the system is in an unstable state during this stage. When the concentration pressure reaches or exceeds 1.3 MPa, the concentration of the concentrated underflow increases significantly, the filter press feeding time shortens to less than 3200 s and tends to converge. The dosing system identifies 1.3 MPa as the inflection point where the physical properties of the system's operating state change abruptly, and sets this value as the pressure threshold. .

[0060] Step S302: The dosing system sets the critical proportion constant. The dosing system retrieves the synergistic sedimentation test data of filter aid and flocculant stored in its internal database. This test aims to determine the specific impact of changes in the amount of filter aid added on the settling velocity of coal slurry water, in order to determine the optimal coupling point between the two agents.

[0061] The experimental method is as follows: First, based on the optimal flocculant consumption per ton of dry coal slime determined in step S102 according to the GB / T 18712-2002 standard, the optimal flocculant consumption value per ton without adding filter aid was determined. Under the experimental conditions of this embodiment, the optimal flocculant concentration per ton was determined to be 13.5. This concentration ensures a basic settling effect. To control for variables and solely examine the effect of the filter aid on the settling system, the amount of flocculant added was fixed at this optimal unit consumption value (i.e., fixed at 13.5). Subsequently, several identical coal slurry water samples of the same volume were taken. While maintaining a constant flocculant dosage, the amount of filter aid added was increased in a gradient, and the settling velocity of the coal slurry water under different filter aid dosages was recorded. Table 2 shows the experimental data of synergistic settling of coal slurry water under different filter aid dosages.

[0062] Table 2. Test data on synergistic settling of coal slurry water under different filter aid dosages

[0063] Analysis of the data in Table 2 shows that as the amount of filter aid increases, the settling velocity of the coal slurry water first decreases and then increases. When the amount of filter aid is between 0 and 150... In the intermediate range, filter aid molecules compete with flocculant molecules for adsorption sites or alter the surface charge of particles, resulting in a settling velocity lower than the baseline value (4.21 mm / s) without filter aid, exhibiting an inhibitory effect. As the filter aid dosage continues to increase to 200... When the settling velocity recovers and exceeds the baseline value, it indicates that the negative inhibitory effect of the filter aid has disappeared and it begins to show its effect of improving the structure of the flocs.

[0064] Select the data corresponding to this inflection point (i.e., filter aid dosage of 200). Flocculant dosage: 13.5 ) calculate the ratio of the two ( And set this ratio as the critical proportionality constant. This parameter is used to lock in the reagent ratio during the low-pressure stage to prevent the thickener from deteriorating due to blindly pursuing filtration efficiency.

[0065] Step S303: The dosing system sets the standard filter press feeding time. The dosing system retrieves experimental data on the correlation between reagent ratios and filter press efficiency stored in its internal database. This experiment aims to determine the impact of different filter aid addition amounts on the filter press feeding cycle during non-low pressure stages, in order to determine the ideal operating state of the system.

[0066] The experimental method is as follows: Under stable operating conditions where the concentration pressure is maintained above 1.3 MPa, the flocculant dosage is kept constant, and the filter aid dosage is gradually adjusted. The feeding time of the filter press (i.e., the time required from the start of feeding to the end of feeding) is recorded. Table 3 shows the test data of filter press feeding time under different filter aid adjustment amounts.

[0067] Table 3. Test data on filter press feeding time under different filter aid adjustment amounts

[0068] The dosing system analyzed the data in Table 3: With increasing filter aid dosage, the filter press feeding time significantly decreased, and the filter cake moisture content reduced. When the filter press feeding time shortened to approximately 2500 seconds, further increasing the filter aid dosage resulted in a gradual reduction in the feeding time (e.g., from 2500 seconds to 2485 seconds). At this point, the increase in reagent cost no longer yielded significant efficiency gains and could easily lead to excessive residual reagent in the filtrate.

[0069] Therefore, the dosing system determined 2500s as the balance point between filtration efficiency and economy, and set this value as the standard filtration loading time. This parameter serves as the control baseline during the non-low pressure phase, based on the actual effective filter press feeding time. Deviation When the system determines that the dosage of the added drug deviates from the optimal range, it triggers reverse feedback adjustment.

[0070] During step S4, which involves determining the operating status and classifying the working conditions of the filter press, the filter press system and the chemical dosing system work together to dynamically adjust the equipment load based on real-time monitored pressure data and determine the current control strategy branch. This process specifically includes the following sub-steps: Step S401: The filter press system performs coordinated control and sequence generation of the filter press group. The filter press system collects the concentration pressure in real time through a pressure sensor installed at the bottom of the thickener. The filter press system internally stores preset automatic queuing control logic for the filter presses. This logic establishes a mapping relationship between the concentration pressure range and the number of filter presses in operation. The filter press system will then use the real-time collected concentration pressure data... The pressure range threshold is compared with the preset pressure range threshold, and the corresponding number of operating units is output. Table 4 shows the pressure range threshold settings and the corresponding equipment scheduling logic.

[0071] Table 4. Comparison of Pressure Range Threshold Settings and Number of Operating Units

[0072] Note: The symbol “-” in Table 4 indicates that under the operating conditions of this pressure range, there is no need to set a specific upper limit threshold or there is no corresponding reference limit requirement for underflow concentration.

[0073] Based on the logic in Table 4, the corresponding number of filter presses are put into operation. Meanwhile, in order to accurately locate specific filter presses for data sampling in subsequent steps, the filter press system has established an equipment status tracking mechanism.

[0074] The filter press system records the start-up time and current operating status (including feeding, pressing, and unloading stages) of each filter press in operation in real time. Based on the order of start-up times, the system sorts all currently operating filter presses (e.g., the earliest started is listed first, the second earliest second), generating a current equipment operating list. This real-time, time-sorted equipment operating list is defined as the operating sequence. This operating sequence is dynamically updated as equipment starts and stops, ensuring that the system can uniquely locate the target equipment at any given time using a sequence index (e.g., "the second machine in the sequence").

[0075] Step S402: The dosing system performs a condition classification judgment. The dosing system acquires the real-time monitoring concentration pressure. And call the pressure threshold value set according to the physical inflection point in step S301. (In this embodiment, (Set to 1.3 MPa). The dosing system executes the numerical comparison logic: If concentration pressure Less than the pressure threshold This indicates that the concentration at the bottom of the thickener has not yet reached a stable high concentration range, and the subsequent feed time data of the filter press fluctuates and contains noise, making it unreliable as a feedback source. The dosing system determines that it is currently in a low-pressure stage and generates a low-pressure mode control signal, triggering the execution of the fusion control strategy in step S5.

[0076] If concentration pressure Greater than or equal to the pressure threshold value This indicates that the underflow properties of the thickener are stable, the filter press is operating in its high-efficiency range, and its operating data can accurately reflect the impact of the chemicals on dewatering performance. The dosing system determines that it is currently in a non-low-pressure stage and generates a non-low-pressure mode control signal, triggering the execution of the fusion control strategy in step S6.

[0077] See attached document Figure 2 When executing the low-pressure phase fusion control strategy in step S5, the dosing system executes a stoichiometric follow-up control mode, which specifically includes the following sub-steps: Step S501: The dosing system acquires input variables. When step S402 determines that the current operating condition is in the low-pressure stage, the dosing system blocks the feedback signal from the filter press system and instead executes open-loop proportional control. The dosing system retrieves the real-time flocculant flow rate generated in step S2 after closed-loop correction. Simultaneously, the dosing system invokes the critical proportion constant set in step S302. (In this embodiment, the value is 14.8).

[0078] Step S502: The dosing system calculates the target flow rate of the filter aid. The dosing system uses the filter aid flow rate formula to calculate the target flow rate of the flocculant based on the real-time flow rate. and critical proportionality constant The input is used to perform calculations to determine the target value of the filter aid flow rate required to maintain the best synergistic effect of the agents under the current operating conditions.

[0079] The formula for filter aid flow rate is shown below: ; In the formula: Indicates the target flow rate of the filter aid; Indicates the real-time flow rate of the flocculant; This represents the critical proportionality constant.

[0080] Through this calculation, the dosing system correlates and locks the amount of filter aid added with the amount of flocculant added, ensuring that the proportion of filter aid in the chemical system is not lower than the critical level that can inhibit sedimentation side effects and promote dehydration.

[0081] Step S503: The dosing system performs frequency adjustment of the filter aid metering pump. The dosing system internally stores the flow-frequency characteristic curve of the filter aid metering pump, which establishes the correspondence between the pump's output frequency and the agent flow rate. Based on this flow-frequency characteristic curve, the dosing system queries or calculates the target filter aid flow rate obtained in step S502. The corresponding physical control frequency. The dosing system sends this frequency command to the variable frequency drive unit of the filter aid metering pump, adjusting the pump frequency to make its output flow rate approach the target flow rate of the filter aid.

[0082] See attached document Figure 3 During the non-low pressure phase of the integrated control strategy in step S6, the dosing system uses the terminal operation data of the filter press system to perform reverse feedback adjustment on the amount of filter aid added, specifically including the following sub-steps: Step S601: The filter press system locks onto the valid sample equipment and collects the valid filter press feeding time. When step S402 determines that the current operating condition is not a low-pressure stage, the filter press system calls the running sequence generated in step S401. To eliminate data deviations caused by the first filter press being started due to residual low-concentration coal slurry water from the previous stage in the feed pipe, the filter press system skips the first-ranked equipment in the running sequence and locks onto the second-ranked filter press as the current sampling object.

[0083] The filter press system monitors the operating status of the second filter press in real time, recording the time span from the issuance of the start feeding command to the issuance of the end feeding command via a filtrate flow meter or an internal program timer. The filter press system defines this time span as the effective filter press feeding time. The data is then transmitted to the dosing system in real time via a communication protocol.

[0084] Step S602: The dosing system performs a reverse feedback calculation based on time deviation. The dosing system receives the effective filter press feeding time. And call the standard filter press feeding time set according to the production capacity target in step S303. The dosing system compares the two values ​​and uses a frequency adjustment formula to calculate the adjustment direction of the filter aid metering pump.

[0085] The frequency adjustment formula is as follows: ; In the formula: This indicates the change in the frequency of the filter aid pump; Indicates the effective filter press feeding time; Indicates the standard filter press feeding time; Indicates the direction of decrease; Indicates the direction of increase; Indicates logical relationships; This indicates conditional judgment logic.

[0086] Step S603: The dosing system performs step adjustment of the filter aid metering pump. The dosing system executes specific frequency conversion operations based on the calculation results of the frequency adjustment formula. If the effective filter press feeding time Less than the standard filter press feeding time This indicates that the current coal slime dewatering rate is faster than the preset ideal target. Based on the law of diminishing marginal returns of the reagents, the filter aid is currently in an over-addition state. The dosing system determines that the filter aid has been added excessively and gradually reduces the frequency of the filter aid metering pump according to the preset step size.

[0087] If the effective filter press feeding time Longer than standard filter press feeding time This indicates that the current coal slime dewatering is difficult and the feeding cycle is too long. The dosing system determines that the filter aid is not added enough and gradually increases the pump frequency of the filter aid metering pump according to the preset step size.

[0088] In addition, to address the process time lag between the dosing point and the filter press, the dosing system activates a hold timer after each frequency adjustment. The duration of this hold timer is set based on the material residence time calculated from the thickener volume and underflow rate. During the set time period, the dosing system maintains the current frequency, ignoring fluctuations in the filter press data, and waits for the adjusted chemical effect to be transmitted to the filter press, awaiting the new effective filter press feeding time. After generation, the next round of feedback adjustment will be carried out.

[0089] Based on the detailed description of the above embodiments, this invention provides a method for integrating a chemical dosing system and a filter press system in a coal preparation plant. By constructing a cross-system closed-loop control logic, this invention solves the problems of disconnection between the chemical dosing and filter press stages, delayed response, and rigid reagent ratios in traditional coal slurry water treatment processes.

[0090] The dosing system and the filter press system achieve real-time sensing of operating conditions and strategy switching through the concentration pressure. The dosing system uses pressure thresholds to divide the operating conditions into low-pressure and non-low-pressure stages. In the low-pressure stage, the dosing system uses a following mechanism established by the critical proportional constant to provide a baseline guarantee for safe system operation; in the non-low-pressure stage, the dosing system uses a reverse feedback mechanism established by the standard filter press feeding time to achieve precise dosing guided by the final dewatering efficiency.

[0091] This fusion method utilizes the effective filter press feeding time as a feedback source, overcoming the time lag caused by long processes, and enabling the reagent dosage to dynamically adapt to changes in coal quality and the actual operating needs of the filter press. Through this fusion, the dosing system can improve the operating efficiency of the filter press system and reduce unnecessary reagent consumption while ensuring the concentration and sedimentation effect.

Claims

1. A method for integrating a chemical dosing system and a filter press system in a coal preparation plant, characterized in that, Includes the following steps: S1. The dosing system performs feedforward calculations based on the real-time collected raw coal quantity and preset process parameters to calculate the target value of flocculant flow rate. S2. The dosing system performs dosing control based on the target value of the flocculant flow rate, and combines turbidity feedback to correct the output frequency, thereby generating the real-time flow rate of the flocculant. S3. The dosing system incorporates preset pressure threshold values, critical proportional constants, and standard filter press feeding times. S4. The filter press system monitors the filter press in real time and controls the operation status and generates the operation sequence based on the concentration pressure of the thickener. The dosing system compares the concentration pressure with the pressure threshold value. If the concentration pressure is less than the pressure threshold value, it is determined to be a low pressure stage; otherwise, it is determined to be a non-low pressure stage. S5. During the low-pressure phase, the dosing system executes a follow-up strategy based on the critical proportion constant, using the real-time flow rate of the flocculant and the critical proportion constant to calculate the target flow rate of the filter aid and adjust the filter aid pump frequency of the filter aid metering pump. S6. During the non-low pressure stage, the dosing system executes a feedback strategy based on the effective filter press feeding time, compares the effective filter press feeding time collected by the filter press system according to the operating sequence with the standard filter press feeding time, and performs reverse feedback adjustment to correct the frequency of the filter aid pump.

2. The method for integrating a chemical dosing system and a filter press system in a coal preparation plant according to claim 1, characterized in that, S1 specifically includes: The dosing system controls the raw coal belt scale to collect the amount of raw coal, and calculates the hourly dry coal slime amount by combining it with the proportion of coal slime product, which is the process parameter. The dosing system uses a dosing algorithm to calculate the target value of the flocculant flow rate based on the hourly dry coal slime quantity, the optimal dosing consumption per ton of dry coal slime determined by coal slime water settling test data stored in the internal database as the process parameters, and the dosing concentration of the flocculant, following the principle of solute conservation. The proportion of coal slime products is a pre-set value based on the process design parameters of the coal preparation plant or statistical analysis of historical production data.

3. The method for integrating a chemical dosing system and a filter press system in a coal preparation plant according to claim 1, characterized in that, S2 specifically includes: The dosing system converts the target value of the flocculant flow rate into a control command based on the preset flocculant flow frequency characteristic curve to adjust the output frequency of the flocculant metering pump; The dosing system uses a turbidity meter to monitor the turbidity of the overflow water from the thickener in real time. When the turbidity exceeds the preset turbidity threshold, the output frequency is gradually adjusted according to the preset flocculant adjustment step size until the turbidity is reduced to below the preset turbidity threshold. After the output frequency is adjusted, the flow rate corresponding to the current actual operating frequency of the flocculant metering pump is determined as the real-time flow rate of the flocculant. The preset flocculant flow frequency characteristic curve is pre-drawn and stored based on the mechanical characteristics of the flocculant metering pump and on-site calibration experiments. The turbidity threshold is a value pre-set based on the water quality process requirements of the coal preparation plant's circulating water. The preset flocculant adjustment step size is a frequency increment or decrement value pre-set based on the lag time and adjustment accuracy of the flocculant metering pump.

4. The method for integrating a chemical dosing system and a filter press system in a coal preparation plant according to claim 1, characterized in that, S3 specifically includes: The dosing system analyzes the filter press feeding time under different concentration pressures in historical data, and determines the physical inflection point when the filter press feeding time changes from a discrete high-fluctuation state to a convergent stable low-value state as the pressure boundary value. Based on the synergistic sedimentation test of filter aid and flocculant, the dosing system determines the dosage ratio point at which the filter aid changes from inhibiting coal slurry sedimentation to promoting or not affecting sedimentation, and sets it as the critical proportional constant. The dosing system calculates the target value of the filter press cycle, which takes into account both filter press efficiency and economy, based on the target production capacity and the upper limit of the ideal dewatering rate of coal slime under the corresponding operating conditions, and sets it as the standard filter press feeding time.

5. The method for integrating a chemical dosing system and a filter press system in a coal preparation plant according to claim 1, characterized in that, In step S4, the real-time monitoring and control of the filter press's operating status and the generation of the operating sequence based on the thickener's concentration pressure by the filter press system specifically includes: The filter press system uses a pressure sensor to monitor the concentration pressure in real time. The filter press system compares the concentration pressure with a preset pressure range threshold to determine the specific pressure range in which the concentration pressure is located. Based on the specific pressure range, the system outputs a number of operating commands to drive the corresponding number of filter presses into operation. The filter press system records the start-up time of each filter press in operation in real time, and sorts all the filter presses in operation according to the order of the start-up times to generate a device work list at the current time. The device work list is defined as the operation sequence. The pressure range threshold is a value preset based on the equipment load capacity corresponding to different pressure ranges in the automatic queuing control logic of the filter press.

6. The method for integrating a chemical dosing system and a filter press system in a coal preparation plant according to claim 1, characterized in that, S5 specifically includes: The dosing system uses the filter aid flow formula to calculate the target flow rate of the filter aid by multiplying the real-time flow rate of the flocculant by the critical proportional constant. The dosing system generates a physical control frequency corresponding to the target flow rate of the filter aid based on the preset filter aid flow frequency characteristic curve, and sends the physical control frequency to the variable frequency drive unit of the filter aid metering pump through an instruction to directly adjust the frequency of the filter aid pump; The preset filter aid flow frequency characteristic curve is pre-drawn and stored based on the mechanical characteristics of the filter aid metering pump and on-site calibration experiments.

7. The method for integrating a chemical dosing system and a filter press system in a coal preparation plant according to claim 1, characterized in that, In step S6, the effective filter press feeding time collected by the filter press system according to the operating sequence specifically includes: The filter press system calls the operation sequence. In the operation sequence, the filter press system skips the first filter press in the order and locks the second filter press in the order as the current sampling object, so as to eliminate the data deviation caused by pipeline residue or excessive concentration of the first filter press to be started. The filter press system collects the time span between the issuance of the start feeding command and the issuance of the end feeding command for the second-ranked filter press, defines it as the effective filter press feeding time, and transmits it to the dosing system.

8. The method for integrating a chemical dosing system and a filter press system in a coal preparation plant according to claim 1, characterized in that, In step S6, performing reverse feedback adjustment to correct the frequency of the filter aid pump specifically includes: The dosing system uses a frequency adjustment formula to compare the received effective filter press feeding time with the standard filter press feeding time; When the effective filter press feeding time is not greater than the standard filter press feeding time, it is determined that the filter aid has been added in excess or the target has been met, and the dosing system gradually reduces the frequency of the filter aid pump according to the preset filter aid adjustment step size. When the effective filter press feeding time is greater than the standard filter press feeding time, it is determined that the filter aid is insufficient, and the dosing system gradually increases the frequency of the filter aid pump according to the preset filter aid adjustment step size. The preset filter aid adjustment step size is a frequency increment or decrement value preset based on the adjustment accuracy of the filter aid metering pump.

9. A method for integrating a chemical dosing system and a filter press system in a coal preparation plant according to claim 1, characterized in that, S6 further includes: After performing an adjustment action on the frequency of the filter aid pump, the dosing system starts a hold timer; During the preset time period of the timer, the dosing system maintains the current frequency, ignores the fluctuation of the filter press data during the period, and waits for the effect of the adjusted agent to be transmitted to the filter press. After the new effective filter press feeding time is generated, the next round of feedback adjustment will be carried out. The preset time period is set based on the material residence time calculated from the volume of the thickener and the underflow rate.

10. A computer device, comprising a processor, a communication interface, a memory, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements a method for integrating a chemical dosing system and a filter press system in a coal preparation plant as described in any one of claims 1-9.

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