Fluidized bed wind resistance model and fluidized bed flow and temperature control method

Abstract

The invention discloses a fluidized bed wind resistance model and a fluidized bed flow control and temperature control method. The fluidized bed wind resistance model comprises a wind cabinet trunk module, a host branch module, a bypass branch module and a gas circuit trunk module, and mathematical model calculation formulas of all the modules are established. A bypass branch is newly added, a novel wind resistance model of the fluidized bed is reconstructed, equivalent calculation formulas of series and parallel circuits are introduced, a correlation calculation model of airflow, wind resistance and wind pressure is obtained, the correlation calculation model is embedded into a fluidized bed control program, detection data are fed back in cooperation with a first flow meter and a second flow meter, and after PID operation of a fluidized bed control system, the flow resistance and wind pressure of the fluidized bed are calculated. The opening degree of the bypass valve 1 and the opening degree of the trunk valve are adjusted and controlled online in real time, long-term stable control over the airflow flow and the temperature of powder in the fluidized bed main machine is achieved, the quality stability of fluidized bed material fluidized drying is greatly improved, the yield is increased, and the rework cost caused by unstable fluidized drying in the prior art is saved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fluidized bed technology, in particular to a fluidized bed air resistance model and a fluidized bed flow control and temperature control method. BACKGROUND

[0002] The fluidized bed is applied to the drying, granulation and coating processes of powders, and has functions such as filtering, dehumidifying, heating and dedusting of the externally introduced air flow. During the dynamic execution of these functions, the air resistance of each link in the fluidized bed system changes dynamically, and then the air flow rate and temperature fluctuate. Meanwhile, the particle size, sphericity and density of the processed powders also have great differences between the initial state and the state in the processing process, which changes the air resistance of the fluidized bed and superimposes the fluctuation of the air flow rate and temperature of the fluidized bed. In the fluidized bed process, the two changes affect the drying, granulation, coating and other process effects of the fluidized bed.

[0003] In the existing fluidized bed products, no effective solution has been formed around the above problems, and there are usually two working modes of the fluidized bed: (1) The fluidized bed adopts a series connection model of each module, and a constant fan working frequency is used in the whole working process. When the air resistance in the dedusting and filtering of the fluidized bed increases, the fan frequency is not feedback controlled, the air flow rate suddenly decreases, the powder in the fluidized bed collapses, and the temperature deviates from the target temperature of the bed layer.

[0004] (2) The fluidized bed adopts a series connection model of each module, and a variable frequency speed regulation is used for the fan in the whole working process. When the air resistance in the dedusting and filtering of the fluidized bed increases, the fluctuation change of the air flow rate is monitored by a flow sensor, and the rotation frequency of the fan is adjusted in real time. This adjustment has a certain effect on maintaining the stability of the bed layer height and temperature of the fluidized bed, but the fan is used as the source of the air flow, the path of the air flow through the air cabinet is long, the response time is long, the fluidization and temperature control of the powder in the main machine of the fluidized bed are delayed, and the fluidization and temperature control are still unstable in the short term.

[0005] The present application is to rebuild a new air resistance model of the fluidized bed, and to realize the long-term stable control of the flow rate and temperature of the powder in the main machine of the fluidized bed by the coordinated feedback control, so as to realize the process effect of the fluidized bed. SUMMARY

[0006] To solve the above-mentioned existing fluidized bed air resistance each module is a series model, the fan adopts frequency conversion speed regulation, when the fluidized bed dust removal air resistance increases, the flow sensor monitors the fluctuation change of air flow, can real-time control the rotation frequency of the fan, has certain effect on maintaining the fluidized bed bed height and temperature stability, but the fan is used as the air path source, the air flow passes through the path of the air cabinet, the response time is long, the fluidization of the powder in the fluidized bed main machine is kept and the temperature control is lagged, the problems of short-term fluidization and temperature control instability still exist, the application provides a fluidized bed air resistance model and a fluidized bed flow control and temperature control method, a bypass branch is added, a new type of fluidized bed air resistance model is reconstructed, and the first flow table and the second flow table are used to feed back detection information, the bypass valve 1 and the dry road valve opening degree are controlled after the PID operation of the fluidized bed control system, the long-term stable control of the air flow and the temperature of the powder in the fluidized bed main machine is realized, the quality stability of the fluidized bed material fluidization drying is greatly improved, the yield is improved, and the rework cost caused by the instability of the prior art fluidization drying is saved.

[0007] To achieve the above object, the application provides a fluidized bed air resistance model, which is a fluidized bed air flow circulation system based air resistance model, the fluidized bed air flow circulation system comprises a wind cabinet dry road module, a main machine branch module, an air path dry road module, a fan, an atmosphere or a pipeline circulation channel and a bypass branch, the bypass branch module is connected in parallel with the main machine branch module, the fluidized bed air resistance is composed of the wind cabinet dry road total air resistance, the main machine branch total air resistance, the bypass branch total air resistance and the air path dry road total air resistance, and the comprehensive mathematical model of the fluidized bed air resistance is: (1) In formula (1) R f is the wind cabinet dry road total air resistance, R g is the air path dry road total air resistance, R z is the main machine branch total air resistance, R p is the bypass branch total air resistance; The wind cabinet dry road module comprises primary filter air resistance, medium filter air resistance, dehumidifier air resistance, cold air valve air resistance, cold air channel air resistance, heating valve air resistance, heater air resistance, heating channel air resistance, primary filter air resistance, medium filter air resistance and dehumidifier air resistance are connected in series, cold air valve air resistance and cold air channel air resistance are connected in series, heating valve air resistance, heater air resistance and heating channel air resistance are connected in series, cold air valve air resistance and cold air channel air resistance are connected in parallel with heating valve air resistance, heater air resistance and heating channel air resistance to form a heating module air resistance, one end of the heating module air resistance is connected with the dehumidifier air resistance, and the other end is connected with the high-efficiency filter air resistance, and the comprehensive mathematical model of the wind cabinet dry road module is: (2) In formula (2), R f is the total air resistance of the air cabinet, R 11 is the air resistance of the primary filter, R 12 is the air resistance of the medium filter, R 01 is the air resistance of the dehumidifier, R 15 is the air resistance of the high-efficiency filter, R fd is the air resistance of the heating module, and the calculation formula of the air resistance of the heating module is: (3) In formula (3), R 13 is the air resistance of the cold air valve, R 02 is the air resistance of the cold air channel, R 14 is the air resistance of the heating valve, R 03 is the air resistance of the heater, and R 04 is the air resistance of the heating channel. The host branch module includes the air resistance of the inlet valve, the air resistance of the cross-section mutation of the host, the air resistance of the material, the air resistance of the fluidized bed chamber, and the air resistance of the dust removal module. The air resistance of the dust removal module includes the air resistance of the left dust removal module and the air resistance of the right dust removal module in parallel. The air resistance of the left dust removal module includes the air resistance of the left dust removal bag, the air resistance of the left dust valve, and the air resistance of the left cross-section mutation connected in series. The air resistance of the right dust removal module includes the air resistance of the right dust removal bag, the air resistance of the right dust valve, and the air resistance of the right cross-section mutation connected in series. The comprehensive mathematical model of the air resistance of the host branch module is: (4) In formula (4), R z is the total air resistance of the host branch, R 16 is the air resistance of the inlet valve, R 05 is the air resistance of the cross-section mutation of the host, R 17 is the air resistance of the material, R 06 is the air resistance of the fluidized bed chamber, and R zc is the air resistance of the dust removal module. In the fluidized production process, the left dust removal module and the right dust removal module have two working states: State 1: both the left dust valve and the right dust valve are opened, and the left dust removal module and the right dust removal module work at the same time. At this time, the calculation formula of the air resistance of the dust removal module is: (5a) State 2: one of the left dust valve and the right dust valve is opened and the other is closed. The corresponding dust removal module works when it is opened, and the corresponding dust removal module performs dust cleaning when it is closed. At this time, the calculation formula of the air resistance of the dust removal module is: (5b) or (5c) In formula (5a, 5b, 5c), Rzc R is the wind resistance of the left dust removal module zc1 R is the wind resistance of the left dust removal module zc2 R is the wind resistance of the right dust removal module 07 R is the wind resistance of the left cross-section mutation 08 R is the wind resistance of the right cross-section mutation 18 R is the wind resistance of the left dust removal bag 19 R is the wind resistance of the left dust removal valve 20 R is the wind resistance of the right dust removal bag 21 R is the wind resistance of the right dust removal valve The bypass branch module includes a bypass valve 1 wind resistance and a bypass valve 2 wind resistance connected in series, and a comprehensive mathematical model of the wind resistance of the bypass branch module is: (6); In formula (6), R p R is the total wind resistance of the bypass branch 22 R is the wind resistance of the bypass valve 1 and R 23 R is the wind resistance of the bypass valve 2; the gas path trunk module includes a trunk valve wind resistance and a pipeline wind resistance, and a comprehensive mathematical model of the wind resistance of the gas path trunk module is: (7).

[0008] In formula (7), R g R is the total wind resistance of the gas path trunk 24 R is the wind resistance of the trunk valve, R 09 R is the wind resistance of the pipeline; As a further improvement of the present technology, the fluidized bed gas circulation system further includes a first flow meter and a second flow meter, the first flow meter is connected in series to the gas cabinet trunk module for monitoring the trunk gas flow I1 of the gas circulation system, and the second flow meter is connected in series to the main machine branch module for monitoring the gas flow I2 of the main machine branch module.

[0009] As a further improvement of the present technology, the primary filter wind resistance, the medium filter wind resistance and the high filter wind resistance gradually increase with the increase of the dust blocking degree during the working process, a first differential pressure sensor is connected in parallel at the inlet and outlet of the primary filter wind resistance, a second differential pressure sensor is connected in parallel at the inlet and outlet of the medium filter wind resistance, and a third differential pressure sensor is connected in parallel at the inlet and outlet of the high filter wind resistance, each differential pressure sensor is used to monitor the pressure difference change before and after the corresponding filter wind resistance to determine the blocking condition of each filter, and the pressure difference change is very small in actual production process of the same batch, and the primary filter wind resistance, the medium filter wind resistance and the high filter wind resistance are all constant values; according to the monitoring condition of each differential pressure sensor, each filter is cleaned or replaced in time to ensure the smoothness of the primary filter, the medium filter and the high filter; The dehumidifier, the cold air channel and the heater, and the heating channel belong to fixed mechanical structures, and the influence on the air resistance is constant during the operation of the fluidized bed, that is, the air resistance of the dehumidifier, the air resistance of the cold air channel, the air resistance of the heater and the air resistance of the heating channel are all constant values; The valve opening degree of the cold air valve + the valve opening degree of the hot air valve = 90°, and the valve opening degrees of the cold air valve and the hot air valve are adjusted according to the initial state according to the fluidization temperature control requirements, and after the initial angle is adjusted, the valve opening degrees are not adjusted during the operation of the fluidized bed, that is, the air resistance of the cold air valve and the air resistance of the hot air valve are constant values during the operation of the fluidized bed. According to formula (1), it can be determined that the air cabinet dry road air resistance R f ≈ constant value.

[0010] As a further improvement of the present technology, the inlet valve opening degree is first set at the beginning of the operation, and after the setting, the structure does not change during the whole operation of the fluidized bed, and the air resistance does not change during the whole operation, that is, the air resistance of the inlet valve is a constant value during the same batch production process. The main machine cross section sudden change air resistance, the fluidized bed chamber air resistance, the left cross section sudden change air resistance and the right cross section sudden change air resistance do not change the air resistance during the whole operation because of the fixed structure, and the air resistance is constant, that is, the main machine cross section sudden change air resistance, the fluidized bed chamber air resistance, the left cross section sudden change air resistance and the right cross section sudden change air resistance are constant values during the production process. The material air resistance can be evaluated by the weight of the material, and as the fluidized bed works, the material air resistance changes in the following formula (8) during the drying process of the material, the solvent evaporation becomes lighter, the particle size increases during the granulation process, the film thickness of the coated pellets increases, and the material air resistance changes in the following formula (8): (8) In formula (8): Bed pressure difference, reflecting air resistance; Total mass of the material; Bed cross-sectional area; The fourth pressure difference sensor is installed on the upper and lower sides of the fluidized bed chamber to monitor the change degree of the material air resistance during the drying process of the material in the fluidized bed chamber. In the dust removal module air resistance, the dust removal left valve and the dust removal right valve present two states of full opening and full closing during the fluidization process, and the air resistance of the dust removal left valve or the air resistance of the dust removal right valve is a constant value when fully opened. During the production process of the fluidized bed, the dust removal module air resistance presents four change states: State 1: The dust removal left valve and the dust removal right valve are both opened, the dust adhered to the left dust removal cloth bag and the right dust removal cloth bag is slight, and the dust removal module air resistance is small; State 2: both the left dust removal valve and the right dust removal valve are opened, the left dust removal bag and the right dust removal bag have more dust adhered, the dust removal bag wind area is reduced, and the dust removal module wind resistance is medium at this time; State 3: the fluidized bed needs to be dedusted due to state 2, at this time, the left dust removal valve or the right dust removal valve is closed, the corresponding left dust removal bag or right dust removal bag is in the airflow occlusion state for ash removal, and the dust removal bag on the other side is in the airflow communication state, but the dust adhered to the dust removal bag on this side is still more, and the dust removal module wind resistance is the largest at this time; State 4: the fluidized bed completes the ash removal and dust removal of one side of the dust removal bag due to state 3, and opens the dust removal valve corresponding to the dust removal bag, closes the dust removal valve on the other side, and changes the ash removal and dust removal of the dust removal bag on the other side, at this time, it is also in the airflow communication state of one side of the dust removal bag, but the dust adhered to the dust removal bag has been removed, and the airway is normal, at this time, the dust removal module wind resistance is medium; The inlet and outlet ends of the left dust removal bag are connected in parallel with the fifth differential pressure sensor, and the inlet and outlet ends of the right dust removal bag are connected in parallel with the sixth differential pressure sensor, for monitoring the change degree of the left dust removal bag wind resistance and the right dust removal bag wind resistance during dust removal, respectively; In actual production, the change of the material wind resistance is very small relative to the change of the dust removal module wind resistance, so the change of the main machine branch total wind resistance R z changes synchronously with the dust removal module wind resistance changes of state 1, state 2, state 3 and state 4.

[0011] As a further improvement of the technology, the bypass valve 1 wind resistance changes with the valve opening size, and the bypass valve 1 valve opening size adjustment is based on the change of the first flowmeter and the second flowmeter and uses PID algorithm feedback adjustment to maintain the constant of the main machine branch flow I2 and the dry road flow I1; The bypass valve 2 is a redundant wind resistance controller, and the bypass valve 2 valve opening is in the full open state under normal working condition, and the bypass valve 2 wind resistance ≈ 0.

[0012] As a further improvement of the technology, the dry road valve wind resistance changes with the valve opening size, and the dry road valve valve opening size adjustment is based on the change of the first flowmeter and the second flowmeter and uses PID algorithm feedback adjustment to maintain the constant of the branch flow I2 and the dry road flow I1; The pipeline structure is fixed, and the wind resistance does not change during the whole fluidized working process, and the pipeline wind resistance is constant.

[0013] As a further improvement of the technology, the calculation formula of the dry road flow I1 is: (9) In formula (9), I1 is the airflow rate of the fluidized bed main circuit; U is the total pressure of the fluidized bed fan; and R is the air resistance of the fluidized bed. R f Total air resistance of the main airflow path of the blower unit; R g Total air resistance of the main gas path; R z Total air resistance of the main unit branch circuit; R p Total wind resistance of the bypass branch; From formula (9), it can be concluded that, under the condition that the total pressure U of the fan is constant, as the total wind resistance of the main unit branch increases... R z As the flow rate I1 of the fluidized bed trunk increases, the airflow rate I1 decreases, and with the increase of the total air resistance of the bypass branch... R p As the flow rate I1 of the fluidized bed trunk increases, the airflow rate I1 also decreases; with the increase of the total air resistance of the trunk airflow... R g As the flow rate decreases, the airflow rate I1 in the fluidized bed trunk increases.

[0014] As a further improvement to this technology, the formula for calculating the host branch flow I2 is as follows: (10) In formula (10), I2 is the airflow rate of the main branch; U is the total pressure of the fluidized bed fan; and R is the air resistance of the fluidized bed. R f Total air resistance of the main airflow path of the blower unit; R g Total air resistance of the main gas path; R z Total air resistance of the main unit branch circuit; R p The total wind resistance of the bypass branch road.

[0015] This invention also provides a fluidized bed flow and temperature control method, which is a fluidized bed flow and temperature control method based on the above-mentioned fluidized bed air resistance model, comprising the following steps: S1. Adjustment of valve opening of cold air valve and heating valve: Before the fluidized bed airflow circulation system starts working, adjust the valve opening of cold air valve and heating valve according to the characteristics of the material to be fluidized, while ensuring the required flow rate and temperature of the dry gas for material fluidization. The valve opening of cold air valve and heating valve determines the temperature value that the heater needs to add. In order to ensure that the heat transfer of the two airflows through the cold air channel and the heating channel is fully carried out, the flow rate of the airflow through the cold air channel and the heating channel should be kept similar. After the initial adjustment of the valve opening of cold air valve and heating valve, no further adjustment is required during the operation of the fluidized bed. S2. Heater Temperature Regulation: The airflows from the cold air channel and the hot air channel converge at their respective ends after passing through their respective channels. After converging, they enter the high-efficiency filter. Before entering the high-efficiency filter, the convergence of the cold and hot airflows achieves heat transfer between them. The combined temperature after the convergence is approximately equal to the target temperature required by the fluidized bed. Obviously, the heat from the airflow heated by the heater passing through the hot air channel needs to be comprehensively supplied to all airflow molecules in both the cold and hot air channels. This allows us to derive the principle of achieving the target temperature T. m The required temperature relationship for heating the airflow in the hot air channel is as follows: (11) In formula (11): Q is the heat of air heating in the hot air channel; C is the specific heat capacity of air; m2 is the mass of air heated in the hot air channel; T2 is the temperature rise of the hot air channel; T0 is the initial temperature of the hot air channel, which is the room temperature; m is the total mass of air heated in the cold air channel and the hot air channel. Therefore, in order to achieve the target temperature T m The required temperature for the gas to be heated in the hot air duct is: (12) Based on the density calculation formula ρ=m / v, we can derive: (13) In the formula, V is the total volume of the cold air passage and the hot air passage, V2 is the volume of the hot air passage, and T2 obtained from formula 13 is the initial set value of the heater temperature. S3. The first differential pressure sensor, the second differential pressure sensor, and the third differential pressure sensor are used to monitor the clogging of the pre-filter, the medium-efficiency filter, and the high-efficiency filter, respectively, to ensure that the pre-filter, the medium-efficiency filter, and the high-efficiency filter are all in a smooth state. The influence of each filter on the air resistance can be ignored. Therefore, according to formula (2), the total air resistance of the main air handling unit can be calculated. R f Determined as a constant value, with R f Based on this, during fluidized bed operation, let: R g = λ 1 R f ; R z = λ 2 R f ; R p = λ 3 R f ; λ1 , λ 2 , λ 3 Let the drag coefficients of the main road, the total drag coefficient of the main engine branch, and the drag coefficient of the bypass branch be respectively. Substituting these values ​​into formulas (9) and (10), we can obtain: (13) (14); S4. Determine the initial operating state of the fluidized bed. λ 1 , λ 2 and λ 3 Values: Under the initial operating conditions of the fluidized bed, differential pressure sensors are installed at both ends of the main air handling unit (BLU), main unit branch, bypass branch, and main gas path, respectively. The differential pressure Uf of the BLU main line, Uz of the main unit branch, Up of the bypass branch, and Ug of the main gas path are detected. The airflow rate I1 of the main line and I2 of the main unit branch are detected using the first and second flow meters. Based on R=U / I, the following values ​​can be calculated: R f , R z , R p and R g The value is then calculated. λ 1 , λ 2 , λ 3 The values ​​of these are denoted as constant values ​​a1, b1, and c1, respectively. S5. Determine the total air resistance of the main unit branch circuit. R z Total air resistance system of the main unit branch under four different states of air resistance of the dust removal module λ 2 Value: Under constant total fan pressure, and with the opening degrees of the cold air valve, hot air valve, bypass valve 1, bypass valve 2, and main valve remaining unchanged, the total air resistance of the main unit branch is... R z As the flow rate increases, the airflow rate in the main unit branch decreases. The airflow rate in the main unit branch under four different states can be detected by the second flow meter. The airflow rate change data fed back from the second flow meter and the initial operating state are then used to determine the airflow rate. λ 2 The value can be used to determine the total wind resistance of the main unit branch. R z Total air resistance system of main unit branch circuits in states 2, 3, and 4 λ 2The values ​​of b1, b2, b3, and b4 are denoted as constant values ​​respectively. S6. Solve for the drag coefficient of the bypass branch. λ 3 and the drag coefficient of the trunk road λ 1 Total air resistance of the main branch circuit R z Values ​​under state 2: The purpose of flow and temperature control is to keep the main airflow rate and the main unit branch airflow rate constant throughout the fluidization process, thereby ensuring the optimal fluidization effect of the material, i.e., I 11 =I 12 I 21 =I 22 I 11 I 12 I represents the main airflow rate in states 1 and 2, respectively. 21 I 22 These represent the airflow rates of the host branch in states 1 and 2, respectively. According to the calculation formula (13), substitute the constant values ​​a1, b1, and c1 obtained in step S2 into I. 11 The calculation formula is to substitute the constant value b2 obtained in step S3 into I. 12 The calculation formula can be obtained as follows: (15) According to the calculation formula (14), substitute the constant values ​​a1, b1, and c1 obtained in step S2 into I. 21 The calculation formula is to substitute the constant value b2 obtained in step S3 into I. 22 The calculation formula can be obtained as follows: (16) The solution for state 2 can be obtained from equations (15) and (16). λ 1 and λ 3 The values ​​of are denoted as constant values ​​a2 and c2; S7. Valve control in state 2: To maintain the original main airflow and main branch airflow in state 1 constant, the total air resistance of the main airflow in state 2 needs to be adjusted to a2 / a1 times the total air resistance of the main airflow in state 1, and the valve opening of the main airflow valve needs to be adjusted to a1 / a2 times the valve opening in state 1. At the same time, the total air resistance of the bypass branch in state 2 needs to be adjusted to c2 / c1 times the total air resistance of the bypass branch in state 1, and the valve opening of bypass valve 1 needs to be adjusted to c1 / c2 times the valve opening in state 1. S8. Solve for states 3 and 4 using the method in step S6. λ 1 and λ3 The value of state 3 λ 1 and λ 3 The values ​​are denoted as constant values ​​a3 and c3, respectively, for state 4. λ 1 and λ 3 The values ​​are denoted as constant values ​​a4 and c4 respectively; the opening of the main valve and the bypass valve 1 in state 3 and state 4 are adjusted respectively using the method in step S7 to achieve the purpose of keeping the main airflow and the main branch airflow constant. S9. Establish a fluidized bed wind resistance simulation model as described in any one of claims 1 to 8 in the fluidized bed control system, write a control program for the flow control and temperature control method of the fluidized bed wind resistance model, and embed formulas (1) to (16) into the control program to form PID calculation. The fluidized bed control system receives real-time detection data from the first flow meter and the second flow meter, performs PID calculation, and issues control commands to the bypass valve 1 and the main valve according to the calculation results to control the valve opening of the bypass valve 1 and the main valve to achieve online automatic real-time control.

[0016] As a further improvement to this technology, in step S1, based on the fact that the ratio of the frontal area of ​​the cold air valve to the heating valve commonly used in fluidized beds is 1:5, the influence of the valve opening of the cold air valve and the heating valve on the uniformity of the airflow velocity through the cold air channel and the hot air channel is expressed by the following formula: (17) In formula (11), y represents the uniformity of airflow velocity. The closer it is to 1, the better the uniformity, and vice versa. x1 is the opening degree of the cold air valve. x2 is the opening degree of the heating valve.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention reconstructs a new fluidized bed wind resistance model by adding a bypass branch, and uses the equivalent calculation formula of series and parallel circuits to obtain a correlation calculation model between airflow rate and wind resistance and wind pressure. This model is then embedded into the fluidized bed control program. In conjunction with the feedback detection data from the first and second flow meters, and after PID calculation by the fluidized bed control system, the opening of the bypass valve 1 and the main valve is adjusted online in real time. This achieves long-term stable control of the airflow rate and temperature of the powder in the fluidized bed host, greatly improving the quality stability of fluidized bed material drying, increasing the yield, and saving the rework costs caused by the instability of fluidized bed drying in the prior art.

[0018] 1. Existing fluidized bed series air resistance modules adjust the fluidized bed airflow and temperature changes due to increased air resistance from the dust removal module by regulating the fan rotation frequency. However, the airflow path through the air handling unit is relatively long, resulting in a long response time. This leads to lag in maintaining fluidization and temperature control of the powder inside the fluidized bed unit, and still results in short-term instability in fluidization and temperature control. This invention, by setting a bypass branch, can control and reduce the valve opening of the bypass valve 1 and the main valve when the air resistance of the main branch increases due to the dust removal module. This enables rapid adjustment of fluidized bed airflow and temperature, keeping them constant throughout the fluidization process and ensuring the quality stability of material fluidized drying. 2. This invention uses the equivalent calculation formulas of series and parallel circuits to derive mathematical operation models of wind resistance, airflow rate and wind pressure for each model. These mathematical operation models are then embedded into the fluidized bed control program. By using feedback information from the first and second flow meters, the control system performs PID calculations and uses the calculation results to adjust the opening of bypass valve 1 and main valve in real time, making the control of fluidized bed airflow rate and temperature more precise and faster. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the fluidized bed airflow circulation system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the opening degree of the cold and hot air valves, where θ is the rotation angle of the hot air valve. Figure 3 The graph shows the relationship between the opening degree of the cold and hot air valves and the total air-facing area of ​​the cold and hot air valves. In the graph, θ is the rotation angle of the hot air valve. Figure 4 a is a process trace diagram of the simulated airflow through the heating module (both the cold air valve and the hot air valve are open at 45°); Figure 4 b is a process trace diagram of the simulated airflow through the heating module (cold air valve opening 30°, hot air valve opening 60°); Figure 4 c is a process trace diagram of the airflow simulation flowing through the heating module (cold air valve opening 60°, hot air valve opening 30°); Figure 5 This is a diagram illustrating the wind resistance system control in an embodiment of the present invention. Figure 6 This is a graph showing the relationship between the drag coefficient of the main road and the drag coefficient of the bypass branch road as a function of the drag coefficient of the main engine branch road in an embodiment of the present invention.

[0020] In the diagram: 1. Main circuit module of the air handling unit, 101. Air resistance of the primary filter, 102. Air resistance of the medium-efficiency filter, 103. Air resistance of the dehumidifier, 104. Air resistance of the cold air valve, 105. Air resistance of the cold air passage, 106. Air resistance of the heating valve, 107. Air resistance of the heater, 108. Air resistance of the heating passage, 109. Air resistance of the high-efficiency filter, 110. First flow meter, 111. First differential pressure sensor, 112. Second differential pressure sensor, 113. Third differential pressure sensor; 2. Main circuit module of the main unit, 201. Air resistance of the inlet valve, 202. Air resistance of the main unit cross-section change, 203. Air resistance of the material, 204. 1. Fluidized bed chamber air resistance; 205. Left dust collector bag air resistance; 206. Dust collector left valve air resistance; 207. Left cross-section sudden change air resistance; 208. Right dust collector bag air resistance; 209. Dust collector right valve air resistance; 210. Right cross-section sudden change air resistance; 211. Second flow meter; 212. Fourth differential pressure sensor; 213. Fifth differential pressure sensor; 214. Sixth differential pressure sensor; 3. Bypass branch module; 301. Bypass valve 1 air resistance; 302. Bypass valve 2 air resistance; 4. Gas main circuit module; 401. Main circuit valve air resistance; 402. Pipeline air resistance; 5. Fan; 6. Atmospheric or pipeline circulation channel. Detailed Implementation

[0021] The technical solutions of 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.

[0022] like Figure 1 As shown, the fluidized bed air resistance model in this embodiment of the invention is an air resistance model based on a fluidized bed airflow circulation system. The fluidized bed airflow circulation system includes a main air handling unit module 1, a main unit branch module 2, a main airflow module 4, a fan 5, an atmospheric or pipeline circulation channel 6, and a bypass branch module 3. The bypass branch module 3 is connected in parallel with the main unit branch module 2. The fluidized bed air resistance consists of the total air resistance of the main air handling unit, the total air resistance of the main unit branch, the total air resistance of the bypass branch, and the total air resistance of the main airflow. The relationship between airflow rate, air pressure, and air resistance in the fluidized bed airflow path is similar to the relationship between current, voltage, and resistance in a series-parallel circuit. Using the equivalent calculation formula for series-parallel circuits, the comprehensive mathematical model of fluidized bed air resistance is obtained as follows: (1) In formula (1) R f The total air resistance of the main airflow path of the blower unit. R g The total air resistance of the main gas path. R z The total air resistance of the main unit branch circuit.R p Total wind resistance of the bypass branch; The main circuit module 1 of the air handling unit includes a primary filter with a resistance of 101, a medium-efficiency filter with a resistance of 102, a dehumidifier with a resistance of 103, a cold air valve with a resistance of 104, a cold air duct with a resistance of 105, a heating valve with a resistance of 106, a heater with a resistance of 107, a heating duct with a resistance of 108, and a high-efficiency filter with a resistance of 109. The primary filter with a resistance of 101, the medium-efficiency filter with a resistance of 102, and the dehumidifier with a resistance of 103 are connected in series. The cold air valve with a resistance of 104 and the cold air duct with a resistance of 109 are also connected in series. 05 are connected in series. The heating valve resistance 106, heater resistance 107, and heating channel resistance 108 are connected in series. The cold air valve resistance 104, cold air channel resistance 105, heating valve resistance 106, heater resistance 107, and heating channel resistance 108 are connected in parallel to form the heating module resistance. One end of this heating module resistance is connected to the dehumidifier resistance 103, and the other end is connected to the high-efficiency filter resistance 109. The comprehensive mathematical model of the resistance of the main circuit module 1 of the air handling unit is as follows: (2) In formula (2), R f For the total air resistance of the main air handling unit, R 11 For the primary filter, the air resistance is 101, R 12 For a medium-efficiency filter with a wind resistance of 102, R 01 The dehumidifier has a wind resistance of 103, R 15 For the high-efficiency filter, the air resistance is 109, R fd The air resistance of the heating module is calculated using the following formula: (3) In formula (3) R 13 The air resistance of the cold air valve is 104, R 02 For the cold air passage, the air resistance is 105, R 14 The air resistance of the heating valve is 106, R 03 The heater has a wind resistance of 107, R 04 The air resistance of the heating channel is 108. The main unit branch module 2 includes the air inlet valve resistance 201, the main unit cross-section abrupt change resistance 202, the material resistance 203, the fluidized bed chamber resistance 204, and the dust removal module resistance. The dust removal module resistance includes the parallel left dust removal module resistance and the right dust removal module resistance. The left dust removal module resistance includes the left dust collector bag resistance 205, the left dust collector valve resistance 206, and the left cross-section abrupt change resistance 207, which are connected in series. The right dust removal module resistance includes the right dust collector bag resistance 208, the right dust collector valve resistance 209, and the right cross-section abrupt change resistance 210, which are connected in series. The comprehensive mathematical model of the air resistance of the main unit branch module 2 is as follows: (4) In formula (4), R z R is the total air resistance of the main unit branch circuit.16 For the air inlet valve, the air resistance is 201, R 05 For the main unit's cross-section, the aerodynamic drag is 202, R 17 For material air resistance 203, R 06 For the fluidized bed chamber air resistance of 204, R zc The air resistance of the dust removal module; In fluidized bed production, the left and right dust removal modules operate in two cooperative states: State 1: Both the left and right dust collector valves are open, and the left and right dust collector modules operate simultaneously. The formula for calculating the air resistance of the dust collector modules at this time is: (5a) State 2: The left and right dust collector valves are open and closed, respectively. The open valve corresponds to the dust collector module in operation, while the closed valve is used for dust cleaning. The formula for calculating the air resistance of the dust collector module at this time is: (5b) or (5c) In formulas (5a, 5b, 5c), R zc For the dust removal module's air resistance, R zc1 For the air resistance of the left dust removal module, R zc2 For the right dust removal module's air resistance, R 07 The abrupt change in drag on the left cross section is 207, R 08 The drag coefficient for the right section is 210, R. 18 The air resistance of the left dust collector bag is 205, R 19 The air resistance of the left valve for dust removal is 206, R 20 The right dust collector bag has an air resistance of 208, R 21 The air resistance of the right valve for dust removal is 209. Bypass branch module 3 includes bypass valve 1 (air resistance 301) and bypass valve 2 (air resistance 302) connected in series. The comprehensive mathematical model of the air resistance of bypass branch module 3 is as follows: (6); In formula (6), R p To account for the total wind resistance of the bypass branch, R 22 For bypass valve 1 air resistance 301 and R 23 The bypass valve 2 has a resistance of 302; the main gas path module 4 includes a main valve resistance of 401 and a pipeline resistance of 402. The comprehensive mathematical model for the resistance of the main gas path module 4 is as follows: (7).

[0023] In formula (7), R g For the total air resistance of the main air circuit, R 24 For the main valve, the air resistance is 401, R 09 The pipeline air resistance is 402; The fluidized bed airflow circulation system also includes a first flow meter 110 and a second flow meter 211. The first flow meter 110 is connected in series to the main circuit module 1 of the air handling unit and is used to monitor the main airflow flow rate I1 of the airflow circulation system. The second flow meter 211 is connected in series to the main branch module and is used to monitor the airflow flow rate I2 of the main branch module 2.

[0024] Air handling unit main circuit module 1: Table 1. Component Symbols and Features of Air Handling Unit Main Circuit Module 1

[0025] The wind resistance changes of each of the above nine components during operation are as follows: The air resistance of the pre-filter 101, medium-efficiency filter 102, and high-efficiency filter 109 gradually increases with the degree of dust blockage during operation. A first differential pressure sensor 111 is connected in parallel at the inlet and outlet of the pre-filter air resistance 101; a second differential pressure sensor 112 is connected in parallel at the inlet and outlet of the medium-efficiency filter air resistance 102; and a third differential pressure sensor 113 is connected in parallel at the inlet and outlet of the high-efficiency filter air resistance 103. Each differential pressure sensor monitors the pressure difference before and after the corresponding filter air resistance to determine the blockage status of each filter. In actual operation, this pressure difference change is relatively slow, especially for a batch of materials. For drying, granulation, or coating processes, the processing time for a single batch generally does not exceed 3 hours. Within 3 hours, the change in air resistance is negligible. Therefore, during a single batch production process, the air resistance of the pre-filter (101), medium-efficiency filter (102), and high-efficiency filter (109) are approximately constant. If used for a long period, the differential pressure of each filter needs to be monitored. To avoid excessive blockage leading to high air resistance, reduced airflow, and increased energy consumption, the filters should be cleaned or replaced promptly based on the monitoring data of each differential pressure sensor to ensure that the pre-filter, medium-efficiency filter, and high-efficiency filter remain unobstructed. The dehumidifier, cold air duct, heater, and heating duct are fixed mechanical structures, and their influence on air resistance is constant during the fluidized bed operation. That is, the air resistance of the dehumidifier (103), the air resistance of the cold air duct (105), the air resistance of the heater, and the air resistance of the heating duct (108) are all constant values. The cold air valve and hot air valve are used to branch and distribute the airflow in the main circuit of the air handling unit. There are two branches, one through the cold air duct and the other through the heater and hot air duct. The opening of the cold air valve + the opening of the hot air valve = 90°.

[0026] like Figure 2As shown, the initial state is defined as the hot air valve being fully open. During the air handling unit temperature adjustment stage: the hot air valve is adjusted by θ, and the cold air valve is adjusted by 90°-θ. Let the air inlet height of the cold air valve be h1; the air inlet height of the hot air valve be h2; and the air inlet width be L. According to geometric relationships, we have: Total airflow area of ​​the cold air valve:

[0027] Hot air valve air passage area:

[0028] The total frontal area of ​​the cold and hot aisles is as follows: (18) Let L be 1.2 (m), h1 be 1 / 6 (m), and h2 be 5 / 6 (m), then we can obtain

[0029] like Figure 3 The figure shows the relationship between the total frontal area of ​​the cold and hot passages and the opening degree θ of the hot air valve. Obviously, although the above adjustment of the cold and hot air valves can change the frontal areas S1, S2 and their proportions of the cold and hot air passages, it cannot guarantee that the total frontal area S is constant. Therefore, adjusting the opening degree of the cold and hot air valves during fluidization will cause changes in the air resistance in the air path, affecting the airflow of the main path.

[0030] like Figure 4 As shown in a, 4b, and 4c, the velocity difference of airflow with the same velocity passing through three different openings of cold and hot air valves, cold air channels, heaters, and hot air channels was simulated simultaneously. The boundary conditions for the simulation analysis were: (1) a pressure difference of 50 Pa; (2) an initial velocity of 2 m / s before airflow in. The velocity results of the airflow at the outlet after passing through the cold air channel, heater, and hot air channel are shown in Table 2 below: Table 2 Results of the Influence of Hot and Cold Air Valve Opening on Airflow Velocity

[0031] As shown in Table 2, the opening degree of the cold and hot air valves directly affects the uniformity of airflow velocity. Through simulation analysis, it is found that a cold air valve opening degree of 60° and a hot air valve opening degree of 30° are effective in maintaining the uniformity of airflow velocity. The uniformity of velocity has a better effect on the convergence and heat transfer of the two airflows passing through the cold air channel and the hot air channel.

[0032] Therefore, given the required airflow rate of the material to be fluidized and dried, once the opening degrees of the cold and hot air valves are initially set, they should not be adjusted in real time during the fluidized bed operation. Otherwise, the air resistance will change, affecting the airflow rate in the main path. Therefore, this invention adjusts the opening degrees of the cold and hot air valves to an initial angle based on temperature control requirements, and then does not adjust them again during fluidized bed operation. That is, during fluidized bed operation, the air resistance 104 of the cold air valve and the air resistance 106 of the hot air valve are both constant values. Therefore, according to formula (1), the air resistance of the main air handling unit during the same batch of production can be determined. R f ≈ constant value.

[0033] Main unit branch module 2: Table 3. Symbols and Characteristics of Main Unit Branch Components

[0034] The wind resistance changes of each of the above 10 components during operation are as follows: The opening of the air inlet valve is set at the beginning of the operation, usually set to 90° fully open. After setting, it does not change during the entire fluidized bed operation. The structure at this point does not affect the air resistance throughout the operation, and the air resistance is constant. That is, the air resistance 201 of the air inlet valve is a constant value in the same batch of production. Since the structure of the main unit cross-section sudden change air resistance 202, fluidized bed chamber air resistance 204, left cross-section sudden change air resistance 207, and right cross-section sudden change air resistance 210 is fixed, the air resistance is not affected throughout the operation and remains constant. That is, the main unit cross-section sudden change air resistance 202, fluidized bed chamber air resistance 204, left cross-section sudden change air resistance 207, and right cross-section sudden change air resistance 210 are all constant values ​​during the production process. The material air resistance 203 can be evaluated by the weight of the material. As the fluidized bed works, the material becomes lighter due to solvent evaporation during drying, heavier due to particle growth during granulation, and heavier due to increased pellet film thickness during coating. The changes in material air resistance 203 are evaluated using the following formula (8): (8) In formula (8): - Bed pressure difference reflects air resistance; -Total mass of materials; - Bed cross-sectional area; A fourth differential pressure sensor 212 is installed on the upper and lower sides of the fluidized bed chamber to monitor the change in material air resistance 203 during the material drying process in the fluidized bed chamber. In the dust removal module's air resistance, the left and right dust removal valves are in two states during fluidization: fully open and fully closed. When fully open, the corresponding air resistance of the left dust removal valve (206) or the right dust removal valve (209) is a constant. During fluidized bed production, the dust removal module's air resistance exhibits four changing states: Status 1: Both the left and right dust removal valves are open, the dust adhering to the left and right dust removal bags is slight, and the dust removal module has low air resistance. State 2: Both the left and right dust removal valves are open. There is a lot of dust adhering to the left and right dust removal bags, and the air passage area of ​​the dust removal bags is reduced. At this time, the air resistance of the dust removal module is moderate. State 3: Due to the occurrence of State 2, the fluidized bed needs to be cleaned. At this time, the left or right dust removal valve is closed, and the corresponding left or right dust removal bag is in a closed airflow state for cleaning. The other side of the dust removal bag is in a connected airflow state, but there is still a lot of dust adhering to the dust removal bag on that side. At this time, the dust removal module has the greatest air resistance. State 4: Due to the occurrence of State 3, the fluidized bed has completed the cleaning and dust removal of one side of the dust collector bag, opened the dust collector valve corresponding to the dust collector bag, closed the dust collector valve on the other side, and switched to cleaning and dust removal of the other side of the dust collector bag. At this time, the airflow is still in the state of one side of the dust collector bag, but the dust adhering on the dust collector bag has been removed, and the airflow has returned to normal level. At this time, the wind resistance of the dust removal module is moderate. A fifth differential pressure sensor 213 is connected in parallel to the inlet and outlet of the left dust collector bag, and a sixth differential pressure sensor 214 is connected in parallel to the inlet and outlet of the right dust collector bag, which are used to monitor the changes in the air resistance 205 of the left dust collector bag and the air resistance 208 of the right dust collector bag during the dust removal process, respectively. In actual production, the change in material resistance 203 is very small compared to the change in dust removal module resistance. Therefore, the total resistance of the main unit branch is relatively small. R z The changes in the resistance of the dust removal module change synchronously with the changes in the air resistance of the dust removal module in states 1, 2, 3 and 4.

[0035] Bypass Module 3: Table 4. Symbols and characteristics of bypass branch components

[0036] The wind resistance changes of each of the two components during operation are as follows: The air resistance 301 of bypass valve 1 changes with the valve opening. The valve opening adjustment of bypass valve 1 is based on the changes of the first flow meter and the second flow meter and adopts PID algorithm feedback adjustment to maintain the constant flow rate I2 of the main branch and the constant flow rate I1 of the main branch. The feedback adjustment of the valve opening of bypass valve 1 has a particularly significant effect on the constant adjustment of I2 flow rate, but a relatively weak effect on the constant adjustment of I1 flow rate.

[0037] Bypass valve 2 is a redundant air resistance controller. Under normal operation, the valve opening of bypass valve 2 is fully open, and the air resistance of bypass valve 2 is approximately 302≈0.

[0038] Gas main circuit module 4: Table 5. Symbols and characteristics of components in the main gas circuit.

[0039] The wind resistance changes of each of the above two components during operation are as follows: The air resistance 401 of the main valve changes with the valve opening. The valve opening adjustment of the main valve is based on the changes of the first flow meter and the second flow meter and adopts PID algorithm feedback adjustment to maintain the constant flow of branch I2 and main flow I1. The feedback adjustment of the valve opening of the main valve has a particularly significant effect on the constant adjustment of I1 flow, but a relatively weak effect on the constant adjustment of I2 flow.

[0040] The pipeline structure is fixed, and the fluidization process does not affect the air resistance. The pipeline air resistance is constant at 402.

[0041] Flow control methods: I. For fluidized beds, the purpose of flow control is to maintain the material in the fluidized bed compartment of the main unit branch in a stable fluidized state at all times, and to eliminate the following phenomena: (1) Insufficient airflow velocity prevents material from fluidizing; (2) If the airflow velocity is too high and the material fluidization height is too high, dust removal blockage is very likely to occur; (3) During the dust removal stage, the airflow velocity drops sharply due to the rapid increase in wind resistance, resulting in bed collapse; (4) The change in fluidization height caused by the change in the specific gravity of the material due to the evaporation of the solvent during the drying, granulation and coating process.

[0042] II. Prerequisites for flow control: Through the construction of the above wind resistance model, the wind resistance of the fluidized bed system is expressed by mathematical formulas. During the entire operation of the fluidized bed, its wind resistance is dynamically changing. This dynamic change in wind resistance leads to changes in the airflow rate in the main and branch lines. These changes affect the fluidization velocity and temperature of the material inside the main unit. The purpose of flow control is to suppress these changes and maintain a continuous and stable fluidization and temperature state for the material. Flow control is mainly achieved through two aspects: the flow rate in the main line and the flow rate in the branch lines. First, it is necessary to determine the calculation methods for the flow rate in the main and branch lines. Before this, it is important to clarify that the total power supply for the fluidized bed is provided by the blower. The overall premise of flow control is based on the condition that the total pressure output by the blower is constant. The total pressure output by the blower consists of two parts: static pressure and dynamic pressure. According to Bernoulli's equation, the total pressure output by the blower is equal and constant whether it is connected to the external main unit or not. For the flow control measures of the fluidized bed, the operating speed of the blower is kept constant. Simultaneously, for a specific blower, its static pressure resistance is constant, while its dynamic pressure depends on the speed at which the blower operates. This determines the two states of the fan. According to Bernoulli's equation, the total pressure of a fan not connected to the main unit is equal to the total pressure of a fan connected to the main unit. The static pressure of the fan depends on its structural characteristics and remains constant. When not connected to the main unit, it can be understood as a single system, with the static pressure being the pressure difference between the fan inlet and outlet. When connected to the main unit, it can also be understood as a single system, with the static pressure being the pressure difference from the inlet of the main unit's air handling unit to the outlet of the fan after flowing through the main unit. The former system has a lower static pressure and a higher airflow velocity at the fan outlet, while the latter system has a higher static pressure and a lower airflow velocity at the fan outlet. The total pressure is the sum of the static pressure and the dynamic pressure (composed of velocity). Therefore, for a fan, its rotational speed determines its output total pressure level. The higher the fan speed, the higher the total pressure level supplied to the external system, the greater its ability to overcome the air resistance of the external main unit, and the higher the airflow velocity formed by the external main unit. When the external air resistance is constant, the airflow velocity formed by the external main unit is greater.

[0043] III. The formula for calculating the main road flow rate I1 is as follows: (9) In formula (9), I1 is the airflow rate of the fluidized bed main circuit; U is the total pressure of the fluidized bed fan; and R is the air resistance of the fluidized bed. R f Total air resistance of the main airflow path of the blower unit; R g Total air resistance of the main gas path; R z Total air resistance of the main unit branch circuit; R p Total wind resistance of the bypass branch; From formula (9), it can be concluded that, under the condition that the total pressure U of the fan is constant, as the total wind resistance of the main unit branch increases... Rz As the flow rate I1 of the fluidized bed trunk increases, the airflow rate I1 decreases, and with the increase of the total air resistance of the bypass branch... R p As the flow rate I1 of the fluidized bed trunk increases, the airflow rate I1 also decreases; with the increase of the total air resistance of the trunk airflow... R g As the flow rate decreases, the airflow rate I1 in the fluidized bed trunk increases.

[0044] IV. The formula for calculating the main branch flow rate I2 is as follows: (10) In formula (10), I2 is the airflow rate of the main branch; U is the total pressure of the fluidized bed fan; and R is the air resistance of the fluidized bed. R f Total air resistance of the main airflow path of the blower unit; R g Total air resistance of the main gas path; R z Total air resistance of the main unit branch circuit; R p The total wind resistance of the bypass branch road.

[0045] From formula (10), it can be concluded that under constant total fan pressure, as the total wind resistance of the main unit branch increases... R z As the airflow rate I2 of the main unit branch increases, the airflow rate of the bypass branch decreases, and the total air resistance of the bypass branch also increases. R p As the airflow rate I2 in the main branch increases, the airflow rate I2 in the main air path also increases; with the increase of the total air resistance in the main air path... R g As the flow rate decreases, the airflow rate I2 in the main branch increases.

[0046] Embodiment 2 of the present invention A fluidized bed flow and temperature control method, based on the above-mentioned fluidized bed air resistance model, includes the following steps: S1. Adjustment of valve opening for cold air valve and heating valve: Based on the fact that the ratio of the frontal area of ​​the cold air valve to the heating valve commonly used in fluidized beds is 1:5, the influence of the valve opening degree of the cold air valve and the heating valve on the uniformity of the airflow velocity through the cold air channel and the hot air channel can be expressed by the following formula: (17) In formula (17), y represents the uniformity of airflow velocity. The closer it is to 1, the better the uniformity, and vice versa. x1 is the opening degree of the cold air valve. x2 is the opening degree of the heating valve.

[0047] Before the fluidized bed airflow circulation system is put into operation, according to the characteristics of the material to be fluidized, under the condition of ensuring the flow rate and temperature of the dry gas required for material fluidization, the valve opening of the cold air valve and the heating valve should be adjusted according to the formula (17). The valve opening of the cold air valve and the heating valve determines the temperature value that the heater needs to add. In order to ensure that the heat transfer of the two airflows through the cold air channel and the heating channel is fully carried out, the flow rate of the airflow through the cold air channel and the heating channel should be kept similar. After the valve opening of the cold air valve and the heating valve is initially adjusted, it will not be adjusted during the operation of the fluidized bed. S2. Heater Temperature Regulation: The airflows from the cold air channel and the hot air channel converge at their respective ends after passing through their respective channels. After converging, they enter the high-efficiency filter. Before entering the high-efficiency filter, the convergence of the cold and hot airflows achieves heat transfer between them. The combined temperature after the convergence is approximately equal to the target temperature required by the fluidized bed. Obviously, the heat from the airflow heated by the heater passing through the hot air channel needs to be comprehensively supplied to all airflow molecules in both the cold and hot air channels. This allows us to derive the principle of achieving the target temperature T. m The required temperature relationship for heating the airflow in the hot air channel is as follows: (11) In formula (11): Q is the heat of air heating in the hot air channel; C is the specific heat capacity of air; m2 is the mass of air heated in the hot air channel; T2 is the temperature rise of the hot air channel; T0 is the initial temperature of the hot air channel, which is the room temperature; m is the total mass of air heated in the cold air channel and the hot air channel. Therefore, in order to achieve the target temperature T m The required temperature for the gas to be heated in the hot air duct is: (12) Based on the density calculation formula ρ=m / v, we can derive: (13) In the formula, V is the total volume of the cold air passage and the hot air passage, V2 is the volume of the hot air passage, and T2 obtained from formula (13) is the initial set value of the heater temperature; S3. The first differential pressure sensor 111, the second differential pressure sensor 112, and the third differential pressure sensor 113 are used to monitor the clogging of the pre-filter, the medium-efficiency filter, and the high-efficiency filter, respectively, to ensure that the pre-filter, the medium-efficiency filter, and the high-efficiency filter are all in a smooth state. The influence of each filter on the air resistance can be ignored. Therefore, according to formula (2), the total air resistance of the main air handling unit can be calculated. R f Determined as a constant value, with R f Based on this, during fluidized bed operation, let: R g= λ 1 R f ; R z = λ 2 R f ; R p = λ 3 R f ; λ 1 , λ 2 , λ 3 Let the drag coefficients of the main road, the total drag coefficient of the main engine branch, and the drag coefficient of the bypass branch be respectively. Substituting these values ​​into formulas (9) and (10), we can obtain: (13) (14); S4. Determine the initial operating state of the fluidized bed. λ 1 , λ 2 and λ 3 Values: Under the initial operating conditions of the fluidized bed, differential pressure sensors are installed at both ends of the main air handling unit (BLU), main unit branch, bypass branch, and main gas path, respectively. The differential pressure Uf of the BLU main line, Uz of the main unit branch, Up of the bypass branch, and Ug of the main gas path are detected. The airflow rate I1 of the main line and I2 of the main unit branch are detected using the first and second flow meters. Based on R=U / I, the following values ​​can be calculated: R f , R z , R p and R g The value is then calculated. λ 1 , λ 2 , λ 3 The values ​​of these are denoted as constant values ​​a1, b1, and c1, respectively. S5. Determine the total air resistance of the main unit branch circuit. R z Total air resistance system of the main unit branch under four different states of air resistance of the dust removal module λ 2Value: Under constant total fan pressure, and with the opening degrees of the cold air valve, hot air valve, bypass valve 1, bypass valve 2, and main valve remaining unchanged, the total air resistance of the main unit branch is... R z As the flow rate increases, the airflow rate I2 in the main unit branch decreases. The airflow rate in the main unit branch under four different states can be detected by the second flow meter 211. The airflow rate change data fed back by the second flow meter 211 and the initial operating state are used to determine the airflow rate. λ 2 The value can be used to determine the total wind resistance of the main unit branch. R z Total air resistance system of main unit branch circuits in states 2, 3, and 4 λ 2 The values ​​of b1, b2, b3, and b4 are denoted as constant values ​​respectively. S6. Solve for the drag coefficient of the bypass branch. λ 3 and the drag coefficient of the trunk road λ 1 Total air resistance of the main branch circuit R z Values ​​under state 2: The purpose of flow and temperature control is to keep the main airflow rate I1 and the main branch airflow rate I2 constant throughout the fluidization process, thereby ensuring the optimal fluidization effect of the material, i.e., I 11 =I 12 I 21 =I 22 I 11 I 12 I represents the main airflow rate in states 1 and 2, respectively. 21 I 22 These represent the airflow rates of the host branch in states 1 and 2, respectively. According to the calculation formula (13), substitute the constant values ​​a1, b1, and c1 obtained in step S2 into I. 11 The calculation formula is to substitute the constant value b2 obtained in step S3 into I. 12 The calculation formula can be obtained as follows: (15) According to the calculation formula (14), substitute the constant values ​​a1, b1, and c1 obtained in step S2 into I. 21 The calculation formula is to substitute the constant value b2 obtained in step S3 into I. 22 The calculation formula can be obtained as follows: (16) The solution for state 2 can be obtained from equations (15) and (16). λ 1 and λ 3 The values ​​of are denoted as constant values ​​a2 and c2; S7. Valve control in state 2: To maintain the original main airflow and main branch airflow in state 1 constant, the total air resistance of the main airflow in state 2 needs to be adjusted to a2 / a1 times the total air resistance of the main airflow in state 1, and the valve opening of the main airflow valve needs to be adjusted to a1 / a2 times the valve opening in state 1; at the same time, the total air resistance of the bypass branch in state 2 needs to be adjusted to c2 / c1 times the total air resistance of the bypass branch in state 1, and the valve opening of bypass valve 1 needs to be adjusted to c1 / c2 times the valve opening in state 1. S8. Solve for states 3 and 4 using the method in step S6. λ 1 and λ 3 The value of state 3 λ 1 and λ 3 The values ​​are denoted as constant values ​​a3 and c3, respectively, for state 4. λ 1 and λ 3 The values ​​are denoted as constant values ​​a4 and c4 respectively; the opening of the main valve and the bypass valve 1 in state 3 and state 4 are adjusted respectively using the method in step S7 to achieve the purpose of keeping the main airflow I1 and the main branch airflow I2 constant. S9. Establish the above-mentioned fluidized bed wind resistance simulation model in the fluidized bed control system, write the flow control and temperature control method control program of the fluidized bed wind resistance model, and embed formulas (1) to (16) into the control program to form PID calculation. The fluidized bed control system receives the real-time detection data of the first flow meter and the second flow meter, performs PID calculation, and issues control commands to the bypass valve 1 and the main valve according to the calculation results to control the valve opening of the bypass valve 1 and the main valve to achieve online automatic real-time control.

[0048] Next, we will analyze the fluidized bed flow control process using a practical case. Based on the four operating states of the fluidized bed, its air resistance is described by the drag coefficient. We will take the air resistance of the main air handling unit module 1 as an example. R f Based on the following table 6: Table 6. Drag coefficients under four operating conditions

[0049] (1) Taking state 1 as the initial state, its influence on airflow rate is as follows: Substituting the data from Table 6 into formula (13), we obtain the fluidized bed trunk airflow rate I. 11 for:

[0050] Substituting the data from Table 6 into formula (14), we obtain the airflow rate I of the main unit branch. 21 for:

[0051] (2) The airflow rate in state 2 is as follows: Fluidized bed trunk airflow rate I 12 for:

[0052] Main unit branch airflow rate I 22 for:

[0053] To maintain the main airflow rate and the main branch airflow rate in state 2 as equal to those in state 1, i.e.: I 11 =I 12 I 21 =I 22 The following two mathematical equations need to be solved:

[0054]

[0055] The solution yields the following: λ 1 =1 / 30, λ 3 =1 / 5 Based on the above analysis, it can be seen that in order to maintain the original airflow rate of state 1, the main road resistance needs to be reduced by (1 / 30) / 0.1 = 1 / 3 times, that is, the valve opening of the main road valve needs to be adjusted to 3 times that of state 1; at the same time, the bypass branch resistance needs to be increased by (1 / 5) / 0.1 = 2 times, that is, the valve opening of bypass valve 1 needs to be adjusted to 1 / 2 times that of state 1.

[0056] (3) The airflow rate in state 3 is as follows: Fluidized bed trunk airflow rate I 13 for:

[0057] Main unit branch airflow rate I 23 for:

[0058] To maintain the main airflow rate and the main branch airflow rate in state 3 as equal to those in state 1, i.e.: I 11 =I 13 I 21 =I 23 The following two mathematical equations need to be solved:

[0059]

[0060] The solution yields the following: λ 1 =0, λ 3 =1 / 4 Based on the above analysis, it can be seen that in order to maintain the original airflow rate of state 1, the main road resistance needs to be reduced to 0, that is, the main road valve needs to be opened to the fully open state; at the same time, the bypass branch resistance needs to be increased by (1 / 4) / 0.1 = 2.5 times, that is, the bypass valve 1 needs to be adjusted to 0.4 times that of state 1.

[0061] (4) The airflow rate in state 4 is the same as that in state 2, so it will not be elaborated further.

[0062] Based on the above analysis and calculations, the drag coefficients for the four states in Table 6 can be clearly defined, resulting in Table 7. Table 7. Drag coefficients under four operating conditions

[0063] The air resistance of the main circuit module 1 of the air handling unit R f Based on this, the air resistance of other modules varies with the air resistance of the main unit's branch circuits. R z Corresponding changes must occur to ensure the constant airflow rate in the main branch and the main unit branch, and their relationship is as follows: Figure 5 As shown. Clearly, given the initial wind resistance of the four main modules, the relationship between the main road wind resistance coefficient and the bypass branch wind resistance coefficient and the main engine branch wind resistance coefficient can be determined, derived as follows:

[0064] With the total wind resistance of the main unit branch circuit R z Increased, total air resistance in the main air circuit R g The total wind resistance of the bypass branch needs to be reduced. R p The increase is needed, and the increase is equal to the total wind resistance of the main unit branch circuit. R z Half of the increase, its trend is as follows Figure 6 As shown.

[0065] The above examples illustrate that to maintain a constant airflow rate between the main unit's branch circuits and the main circuit, the total air resistance of the main circuit of the air handling unit should be known in the initial state. R fUnder these conditions, the total wind resistance around the main unit branch circuit R z The air resistance of the bypass branch module and the main gas circuit module is adjusted in real time according to the changes in air resistance. The air resistance of the bypass branch module and the main gas circuit module is achieved by controlling the opening of the bypass valve 1 and the main gas circuit valve, respectively.

[0066] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make several improvements and substitutions without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A fluidized bed air resistance model, which is an air resistance model based on a fluidized bed airflow circulation system, wherein the fluidized bed airflow circulation system includes a main air handling unit module, a main unit branch module, an air path main module, a fan, and an atmospheric or pipeline circulation channel, characterized in that: The fluidized bed airflow circulation system also includes a bypass branch module, which is connected in parallel with the main unit branch module. The fluidized bed air resistance is composed of the total air resistance of the air handling unit main line, the total air resistance of the main unit branch line, the total air resistance of the bypass branch line, and the total air resistance of the main air path. The comprehensive mathematical model of the fluidized bed air resistance is as follows: （1） In formula (1) R f The total air resistance of the main airflow path of the blower unit. R g The total air resistance of the main gas path. R z The total air resistance of the main unit branch circuit. R p Total wind resistance of the bypass branch; The main circuit module of the air handling unit includes the air resistance of the pre-filter, medium-efficiency filter, dehumidifier, cold air valve, cold air duct, heating valve, heater, heating duct, and high-efficiency filter. The air resistances of the pre-filter, medium-efficiency filter, and dehumidifier are connected in series. The air resistances of the cold air valve and cold air duct are connected in series. The air resistances of the heating valve, heater, and heating duct are connected in series. The air resistances of the cold air valve and cold air duct are connected in parallel with those of the heating valve, heater, and heating duct to form the air resistance of the heating module. One end of the air resistance of the heating module is connected to the dehumidifier air resistance, and the other end is connected to the high-efficiency filter air resistance. The comprehensive mathematical model of the air resistance of the main circuit module of the air handling unit is as follows: （2） In formula (2), R f For the total air resistance of the main air handling unit, R 11 For the air resistance of the primary filter, R 12 For medium-efficiency filters, R 01 For the dehumidifier's air resistance, R 15 To reduce the air resistance of the high-efficiency filter, R fd The air resistance of the heating module is calculated using the following formula: （3） In formula (3) R 13 For the air resistance of the cold air valve, R 02 For the air resistance of the cold air passage, R 14 For the air resistance of the heating valve, R 03 For the heater air resistance, R 04 To reduce air resistance in the heating channel; The main unit branch module includes the air inlet valve resistance, the main unit cross-sectional change resistance, the material resistance, the fluidized bed chamber resistance, and the dust removal module resistance. The dust removal module resistance includes the parallel left dust removal module resistance and the right dust removal module resistance. The left dust removal module resistance includes the left dust collector bag resistance, the left dust collector valve resistance, and the left cross-sectional change resistance connected in series. The right dust removal module resistance includes the right dust collector bag resistance, the right dust collector valve resistance, and the right cross-sectional change resistance connected in series. The comprehensive mathematical model for the air resistance of the main unit branch module is as follows: （4） In formula (4), R z R is the total air resistance of the main unit branch circuit. 16 For the air intake valve air resistance, R 05 For the abrupt change in air resistance of the main unit cross section, R 17 For material air resistance, R 06 To reduce the air resistance of the fluidized bed compartment, R zc The air resistance of the dust removal module; In fluidized bed production, the left and right dust removal modules operate in two cooperative states: State 1: Both the left and right dust collector valves are open, and the left and right dust collector modules operate simultaneously. The formula for calculating the air resistance of the dust collector modules at this time is: （5a） State 2: The left and right dust collector valves are open and closed, respectively. The open valve corresponds to the dust collector module in operation, while the closed valve is used for dust cleaning. The formula for calculating the air resistance of the dust collector module at this time is: （5b） or (5c) In formulas (5a, 5b, 5c), R zc For the dust removal module's air resistance, R zc1 For the air resistance of the left dust removal module, R zc2 For the right dust removal module's air resistance, R 07 For the abrupt change in drag on the left cross section, R 08 For the abrupt change in drag on the right side, R 18 To reduce the air resistance of the left dust collector bag, R 19 To reduce the air resistance of the left valve for dust removal, R 20 To reduce the air resistance of the right dust collector bag, R 21 Dust removal right valve air resistance; The bypass branch module includes bypass valve 1 and bypass valve 2 connected in series. The comprehensive mathematical model of the bypass branch module's air resistance is as follows: （6）； In formula (6), R p To account for the total wind resistance of the bypass branch, R 22 For bypass valve 1 air resistance and R 23 For bypass valve 2 air resistance; The main gas path module includes the air resistance of the main gas path valve and the air resistance of the pipeline. The comprehensive mathematical model of the air resistance of the main gas path module is as follows: （7）； In formula (7), R g For the total air resistance of the main air circuit, R 24 For the air resistance of the main valve, R 09 For pipeline air resistance.

2. The fluidized bed air resistance model according to claim 1, characterized in that: The fluidized bed airflow circulation system also includes a first flow meter and a second flow meter. The first flow meter is connected in series to the main circuit module of the air handling unit and is used to monitor the main airflow flow rate I1 of the airflow circulation system. The second flow meter is connected in series to the main branch circuit module and is used to monitor the airflow flow rate I2 of the main branch circuit module.

3. The fluidized bed air resistance model according to claim 1, characterized in that: The air resistance of the pre-filter, medium-efficiency filter, and high-efficiency filter gradually increases with the degree of dust blockage during operation. A first differential pressure sensor is connected in parallel at the inlet and outlet of the pre-filter air resistance, a second differential pressure sensor is connected in parallel at the inlet and outlet of the medium-efficiency filter air resistance, and a third differential pressure sensor is connected in parallel at the inlet and outlet of the high-efficiency filter air resistance. Each differential pressure sensor is used to monitor the pressure difference before and after the corresponding filter air resistance to determine the blockage status of each filter. In actual production within the same batch, this pressure difference change is very small, and the air resistance of the pre-filter, medium-efficiency filter, and high-efficiency filter are all approximately constant. Based on the monitoring data of each differential pressure sensor, each filter is cleaned or replaced in a timely manner to ensure that the pre-filter, medium-efficiency filter, and high-efficiency filter are unobstructed. The dehumidifier, cold air duct, heater, and heating duct are fixed mechanical structures, and their influence on air resistance is constant during the fluidized bed operation. That is, the air resistance of the dehumidifier, cold air duct, heater, and heating duct are all constant values. The opening degree of the cold air valve + the opening degree of the hot air valve = 90°. The opening degree of the cold air valve and the hot air valve are initially adjusted to an initial angle according to the fluidization temperature control requirements. They are not adjusted during the fluidized bed operation. That is, the air resistance of the cold air valve and the air resistance of the hot air valve are both constant during the fluidized bed operation. According to formula (1), the air resistance of the main air handling unit in the same batch of production process can be determined. R f ≈ constant value.

4. The fluidized bed air resistance model according to claim 1, characterized in that: The opening degree of the air inlet valve is set at the beginning of the operation. After the setting, it does not change during the entire fluidized bed operation. The structure at this point does not affect the air resistance throughout the operation, and the air resistance is constant. That is, the air resistance of the air inlet valve is a constant value during the same batch of production. The sudden change in air resistance of the main unit cross section, the fluidized bed chamber air resistance, the sudden change in air resistance of the left section, and the sudden change in air resistance of the right section are all constant because the structure is fixed and does not affect the air resistance throughout the entire operation. That is, the sudden change in air resistance of the main unit cross section, the fluidized bed chamber air resistance, the sudden change in air resistance of the left section, and the sudden change in air resistance of the right section are all constant values ​​during the production process. Material air resistance can be evaluated by material weight. As the fluidized bed progresses, the material becomes lighter due to solvent evaporation during drying, heavier due to particle growth during granulation, and heavier due to increased pellet film thickness during coating. The changes in material air resistance are evaluated using the following formula (8): （8） In formula (8): - Bed pressure difference reflects air resistance; -Total mass of materials; - Bed cross-sectional area; A fourth differential pressure sensor is installed on the upper and lower sides of the fluidized bed chamber to monitor the change in material air resistance during the material drying process in the fluidized bed chamber. In the dust removal module's air resistance, the left and right dust removal valves are in two states during fluidization: fully open and fully closed. When fully open, the corresponding air resistance of either the left or right dust removal valve is a constant value. During fluidized bed production, the dust removal module's air resistance exhibits four changing states: Status 1: Both the left and right dust collector valves are open, the dust adhering to the left and right dust collector bags is slight, and the dust collector module has low air resistance. State 2: Both the left and right dust removal valves are open. There is a lot of dust adhering to the left and right dust removal bags, and the air passage area of ​​the dust removal bags is reduced. At this time, the air resistance of the dust removal module is moderate. State 3: Due to the occurrence of State 2, the fluidized bed needs to be cleaned. At this time, the left or right dust removal valve is closed, and the corresponding left or right dust removal bag is in a closed airflow state for cleaning. The other side of the dust removal bag is in a connected airflow state, but there is still a lot of dust adhering to the dust removal bag on that side. At this time, the dust removal module has the greatest air resistance. State 4: Due to the occurrence of State 3, the fluidized bed has completed the cleaning and dust removal of one side of the dust collector bag, opened the dust collector valve corresponding to the dust collector bag, closed the dust collector valve on the other side, and switched to cleaning and dust removal of the other side of the dust collector bag. At this time, the airflow is still in the state of one side of the dust collector bag, but the dust adhering on the dust collector bag has been removed, and the airflow has returned to normal level. At this time, the wind resistance of the dust removal module is moderate. A fifth differential pressure sensor is connected in parallel to the inlet and outlet of the left dust collector bag, and a sixth differential pressure sensor is connected in parallel to the inlet and outlet of the right dust collector bag, which are used to monitor the changes in the air resistance of the left and right dust collector bags during the dust removal process, respectively. In actual production, the change in material air resistance is very small compared to the change in dust removal module air resistance. Therefore, the total air resistance of the main unit branch is very small. R z The changes in the resistance of the dust removal module change synchronously with the changes in the air resistance of the dust removal module in states 1, 2, 3 and 4.

5. A fluidized bed air resistance model according to claim 1, characterized in that: The air resistance of the bypass valve 1 varies with the valve opening. The valve opening of the bypass valve 1 is adjusted by using a PID algorithm feedback adjustment based on the changes in the first flow meter and the second flow meter, in order to maintain the constant flow rate I2 of the main branch and the flow rate I1 of the main branch. Bypass valve 2 is a redundant air resistance controller. Under normal operation, the valve opening of bypass valve 2 is fully open, and the air resistance of bypass valve 2 is approximately 0.

6. The fluidized bed air resistance model according to claim 1, characterized in that: The air resistance of the main valve changes with the valve opening. The valve opening is adjusted by using a PID algorithm based on the changes in the first and second flow meters to maintain the branch flow rate I2 and the main flow rate I1 constant. The pipeline structure is fixed, and the fluidization process does not affect the air resistance, so the pipeline air resistance remains constant.

7. A fluidized bed air resistance model according to claim 1, characterized in that: The formula for calculating the main road flow rate I1 is: （9） In formula (9), I1 is the airflow rate of the fluidized bed main circuit; U is the total pressure of the fluidized bed fan; and R is the air resistance of the fluidized bed. R f Total air resistance of the main airflow path of the blower unit; R g Total air resistance of the main air circuit; R z Total air resistance of the main unit branch circuit; R p Total wind resistance of the bypass branch; From formula (9), it can be concluded that, under the condition that the total pressure U of the fan is constant, as the total wind resistance of the main unit branch increases... R z As the flow rate I1 of the fluidized bed trunk increases, the airflow rate I1 decreases, and with the increase of the total air resistance of the bypass branch... R p As the flow rate increases, the airflow rate I1 in the fluidized bed trunk also decreases; With the total air resistance of the main air circuit R g As the flow rate decreases, the airflow rate I1 in the fluidized bed trunk increases.

8. A fluidized bed air resistance model according to claim 1, characterized in that: The formula for calculating the host branch flow I2 is: （10） In formula (10), I2 is the airflow rate of the main branch; U is the total pressure of the fluidized bed fan; R f Total air resistance of the main airflow path of the blower unit; R g Total air resistance of the main air circuit; R z Total air resistance of the main unit branch circuit; R p The total wind resistance of the bypass branch road.

9. A fluidized bed flow and temperature control method, which is a fluidized bed flow and temperature control method based on the fluidized bed air resistance model according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Adjustment of valve opening of cold air valve and heating valve: Before the fluidized bed airflow circulation system starts working, adjust the valve opening of cold air valve and heating valve according to the characteristics of the material to be fluidized, while ensuring the required flow rate and temperature of the dry gas for material fluidization. The valve opening of cold air valve and heating valve determines the temperature value that the heater needs to add. In order to ensure that the heat transfer of the two airflows through the cold air channel and the heating channel is fully carried out, the flow rate of the airflow through the cold air channel and the heating channel should be kept similar. After the initial adjustment of the valve opening of cold air valve and heating valve, no further adjustment is required during the operation of the fluidized bed. S2. Heater Temperature Regulation: The airflows from the cold air channel and the hot air channel converge at their respective ends after passing through their respective channels. After converging, they enter the high-efficiency filter. Before entering the high-efficiency filter, the convergence of the cold and hot airflows achieves heat transfer between them. The combined temperature after the convergence is approximately equal to the target temperature required by the fluidized bed. Obviously, the heat from the airflow heated by the heater passing through the hot air channel needs to be comprehensively supplied to all airflow molecules in both the cold and hot air channels. This allows us to derive the principle of achieving the target temperature T. m The required temperature relationship for heating the airflow in the hot air channel is as follows: （11） In formula (11): Q is the heat of air heating in the hot air channel; C is the specific heat capacity of air; m2 is the mass of air heated in the hot air channel; T2 is the temperature rise of the hot air channel; T0 is the initial temperature of the hot air channel, which is the room temperature; m is the total mass of air heated in the cold air channel and the hot air channel. Therefore, in order to achieve the target temperature T m The required temperature for the gas to be heated in the hot air duct is: （12） Based on the density calculation formula ρ=m / v, we can derive: （13） In the formula, V is the total volume of the cold air passage and the hot air passage, V2 is the volume of the hot air passage, and T2 obtained from formula 13 is the initial set value of the heater temperature. S3. The first differential pressure sensor, the second differential pressure sensor, and the third differential pressure sensor are used to monitor the clogging of the pre-filter, the medium-efficiency filter, and the high-efficiency filter, respectively, to ensure that the pre-filter, the medium-efficiency filter, and the high-efficiency filter are all in a smooth state. The influence of each filter on the air resistance can be ignored. Therefore, according to formula (2), the total air resistance of the main air handling unit can be calculated. R f Determined as a constant value, with R f Based on this, during fluidized bed operation, let: R g =λ 1 R f ; R z =λ 2 R f ; R p =λ 3 R f ; λ 1 , λ 2 , λ 3 Let the drag coefficients of the main road, the total drag coefficient of the main engine branch, and the drag coefficient of the bypass branch be respectively. Substituting these values ​​into formulas (9) and (10), we can obtain: （13） （14）； S4. Determine the initial operating state of the fluidized bed. λ 1 , λ 2 and λ 3 Values: Under the initial operating conditions of the fluidized bed, differential pressure sensors are installed at both ends of the main air handling unit (BLU), main unit branch, bypass branch, and main gas path, respectively. The differential pressure Uf of the BLU main line, Uz of the main unit branch, Up of the bypass branch, and Ug of the main gas path are detected. The airflow rate I1 of the main line and I2 of the main unit branch are detected using the first and second flow meters. Based on R=U / I, the following values ​​can be calculated: R f , R z , R p and R g The value is then calculated. λ 1 , λ 2 , λ 3 The values ​​of these are denoted as constant values ​​a1, b1, and c1, respectively. S5. Determine the total air resistance of the main unit branch circuit. R z Total air resistance system of the main unit branch under four different states of air resistance of the dust removal module λ 2 Value: Under constant total fan pressure, and with the opening degrees of the cold air valve, hot air valve, bypass valve 1, bypass valve 2, and main valve remaining unchanged, the total air resistance of the main unit branch is... R z As the flow rate increases, the airflow rate in the main unit branch decreases. The airflow rate in the main unit branch under four different states can be detected by the second flow meter. The airflow rate change data fed back from the second flow meter and the initial operating state are then used to determine the airflow rate. λ 2 The value can be used to determine the total wind resistance of the main unit branch. R z Total air resistance system of main unit branch circuits in states 2, 3, and 4 λ 2 The values ​​of b1, b2, b3, and b4 are denoted as constant values ​​respectively. S6. Solve for the drag coefficient of the bypass branch. λ 3 and the drag coefficient of the trunk road λ 1 Total air resistance of the main branch circuit R z Values ​​under state 2: The purpose of flow and temperature control is to keep the main airflow rate and the main unit branch airflow rate constant throughout the fluidization process, thereby ensuring the optimal fluidization effect of the material, i.e., I 11 =I 12 I 21 =I 22 I 11 I 12 I represents the main airflow rate in states 1 and 2, respectively. 21 I 22 These represent the airflow rates of the host branch in states 1 and 2, respectively. According to the calculation formula (13), substitute the constant values ​​a1, b1, and c1 obtained in step S2 into I. 11 The calculation formula is to substitute the constant value b2 obtained in step S3 into I. 12 The calculation formula can be obtained as follows: (15) According to the calculation formula (14), substitute the constant values ​​a1, b1, and c1 obtained in step S2 into I. 21 The calculation formula is to substitute the constant value b2 obtained in step S3 into I. 22 The calculation formula can be obtained as follows: (16) The solution for state 2 can be obtained from equations (15) and (16). λ 1 and λ 3 The values ​​of are denoted as constant values ​​a2 and c2; S7. Valve control in state 2: To maintain the original main airflow and main branch airflow in state 1 constant, the total air resistance of the main circuit in state 2 needs to be adjusted to a2 / a1 times the total air resistance of the main circuit in state 1, and the valve opening of the main circuit valve needs to be adjusted to a1 / a2 times the valve opening in state 1; at the same time, the total air resistance of the bypass branch in state 2 needs to be adjusted to c2 / c1 times the total air resistance of the bypass branch in state 1, and the valve opening of bypass valve 1 needs to be adjusted to c1 / c2 times the valve opening in state 1. S8. Solve for states 3 and 4 using the method in step S6. λ 1 and λ 3 The value of state 3 λ 1 and λ 3 The values ​​are denoted as constant values ​​a3 and c3, respectively, for state 4. λ 1 and λ 3 The values ​​are denoted as constant values ​​a4 and c4, respectively. The opening of the main valve and the opening of the bypass valve 1 in states 3 and 4 are adjusted respectively using the method in step S7 to achieve the purpose of keeping the airflow of the main circuit and the airflow of the main unit branch constant. S9. Establish a fluidized bed wind resistance simulation model as described in any one of claims 1 to 8 in the fluidized bed control system, write a control program for the flow control and temperature control method of the fluidized bed wind resistance model, and embed formulas (1) to (16) into the control program to form PID calculation. The fluidized bed control system receives real-time detection data from the first flow meter and the second flow meter, performs PID calculation, and issues control commands to the bypass valve 1 and the main valve according to the calculation results to control the valve opening of the bypass valve 1 and the main valve to achieve online automatic real-time control.

10. The method for controlling flow and temperature in a fluidized bed air resistance model according to claim 9, characterized in that: In step S1, based on the common ratio of the frontal area of ​​the cold air valve to the heating valve in fluidized beds being 1:5, the influence of the valve opening of the cold air valve and the heating valve on the uniformity of the airflow velocity through the cold air channel and the hot air channel can be expressed by the following formula: （17） In formula (11), y represents the uniformity of airflow velocity. The closer it is to 1, the better the uniformity, and vice versa. x1 is the opening degree of the cold air valve. x2 is the opening degree of the heating valve.

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