A spirulina powder granulation temperature monitoring control method

Abstract

The present application relates to the technical field of granulation production monitoring, and particularly relates to a spirulina powder granulation temperature monitoring control method. The present application synchronously collects torque, rotating speed, temperature and flow parameters, and fuses calculation of mechanical heat power and cooling power, so as to realize real-time adjustment of cooling medium flow, and maintain heat balance of the granulation process. The present application analyzes the cooperative relationship between torque change rate and temperature gradient, so as to realize accurate determination of the granulation completion end point, avoid misjudgment caused by dependence on fixed time or single temperature threshold, effectively prevent insufficient granule strength caused by premature end or overheating of the material caused by late end, and guarantee the quality of spirulina powder active ingredients and granule formation.

Description

Technical Field

[0001] This invention relates to the field of temperature control technology for granulation production monitoring, specifically to a method for monitoring and controlling the temperature during spirulina powder granulation. Background Technology

[0002] The typical production process for spirulina powder granulation mainly includes: raw material pretreatment and mixing, conditioning, granulation, drying, cooling, and screening and packaging. In the entire process chain, granulation is the core process, aiming to form granules from the conditioned material through the ring die holes using pressure rollers. During this process, intense friction generates heat between the material and the ring die and pressure rollers. Combined with the residual heat from the conditioning process, this leads to a rise in the material temperature, making it a passive and continuously heat-generating process.

[0003] As a heat-sensitive material, temperature control during the granulation process of spirulina powder is crucial. Excessive temperature can lead to the loss of highly active ingredients such as proteins and phycocyanin; insufficient temperature can result in loosely formed granules with insufficient strength.

[0004] However, current technologies for controlling granulation temperature mainly rely on preset adjustments to conditioning temperature and material moisture content parameters, as well as indirect and delayed heat dissipation by introducing cooling water into the granulator jacket. This method cannot quantify the dynamic changes in temperature within the granulation chamber, resulting in a delayed and ineffective cooling system response. It is difficult to achieve a dynamic balance between heat generation and dissipation, affecting the granulation quality of spirulina powder and the consistency of granulation quality between batches. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art by synchronously collecting mechanical and thermodynamic parameters of the granulation process and calculating mechanical heat power and cooling power in real time to obtain the target value of cooling medium flow rate, thereby achieving dynamic and precise temperature control; furthermore, by comprehensively considering torque change rate and temperature gradient, the endpoint of granulation is intelligently determined, and a programmed cooling process is adopted to ensure the forming quality and consistency of spirulina powder granulation.

[0006] The technical solution adopted by the present invention to solve its technical problem is: a method for monitoring and controlling the temperature of spirulina powder granulation, comprising the following steps: synchronously collecting the material temperature at key locations inside the granulation chamber, the torque and speed of the drive shaft of the main motor, and the inlet and outlet temperatures and flow rates of the jacket cooling medium.

[0007] By integrating the mechanical thermal power calculated from the drive shaft torque and speed, and the cooling power calculated from the inlet and outlet temperatures and flow rates of the cooling medium, the target value of the cooling flow rate is finally obtained; the cooling system is controlled to adjust the cooling medium flow rate in real time according to the target value of the cooling flow rate.

[0008] The system calculates the temperature gradient between the torque change rate and the material temperature at key locations. When the torque change rate and temperature gradient satisfy a preset functional relationship, a granulation completion signal is generated. Subsequently, the program cooling process is initiated, and the cooling system is controlled to perform subsequent cooling operations.

[0009] Record the moment when the torque change rate first falls below the baseline change rate, the maximum value of the temperature gradient, and the cumulative value of mechanical thermal power during the granulation process of each batch.

[0010] Before the start of the next batch of granulation, if the torque change rate of the current batch at a certain moment is greater than the average value of the historical batches at the same moment, the target value of cooling flow rate will be increased under the same mechanical thermal power conditions.

[0011] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention achieves real-time adjustment of the flow rate of the cooling medium by synchronously collecting torque, speed, temperature and flow parameters, and integrating and calculating mechanical heat power and cooling power, so as to maintain the thermal balance of the granulation process.

[0012] 2. This invention achieves accurate judgment of the granulation endpoint by analyzing the synergistic relationship between torque change rate and temperature gradient, avoiding misjudgment caused by relying on fixed time or a single temperature threshold, effectively preventing insufficient particle strength due to premature termination or overheating of materials due to premature termination; at the same time, it uses the trend of material temperature change as feedback to execute the program cooling process; thereby ensuring the quality of spirulina powder active ingredients and granule formation.

[0013] 3. This invention records key parameters for each batch and adjusts the cooling strategy based on historical data before granulation of subsequent batches, adapting to the differences in materials between different batches, thereby solving the problem of inconsistent molding quality between batches caused by material fluctuations and temperature fluctuations. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the control method of the present invention.

[0016] Figure 2 This is a schematic diagram of the process for obtaining the target value of cooling flow rate according to the present invention.

[0017] Figure 3 This is a schematic diagram of the process for generating the granulation completion signal according to the present invention.

[0018] Figure 4This is a schematic diagram of the process for increasing the target value of cooling flow rate under the same mechanical thermal power conditions according to the present invention. Detailed Implementation

[0019] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. Furthermore, it should be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale.

[0020] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification.

[0021] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0023] The following description, in conjunction with the accompanying drawings, details the specific scheme of the spirulina powder granulation temperature monitoring and control method provided by the present invention.

[0024] Please see Figure 1 The diagram illustrates a flowchart of a method for monitoring and controlling the temperature during spirulina powder granulation, provided by the present invention. The method specifically includes the following steps: Step S1: Establish key monitoring locations within the spirulina powder granulation equipment. These key locations include, but are not limited to, the near-wall area, the central area, and the outlet area of ​​the granulation chamber. Simultaneously collect data on the material temperature, the drive shaft torque and speed of the main motor, and the inlet and outlet temperatures and flow rates of the jacket cooling medium at these key locations within the granulation chamber.

[0025] The reason for simultaneously collecting the above parameters is that the temperature during the spirulina powder granulation process mainly comes from two sources: first, the heat generated by mechanical shearing and friction; and second, the heat removed by the cooling system. Considering both aspects allows for more precise temperature control during the spirulina powder granulation process, ensuring the quality of the spirulina powder granules.

[0026] The torque and speed of the main motor's drive shaft reflect the mechanical load and energy input during the granulation process, thus determining the heat generated by mechanical shearing and friction. The inlet and outlet temperatures and flow rates of the jacket cooling medium directly determine the system's heat removal capacity and efficiency.

[0027] In practice, temperature can be acquired using a high-temperature resistant and non-adhesive temperature sensor; torque and speed can be obtained through a torque meter and encoder installed on the main motor drive shaft; and the flow rate of the cooling medium can be measured by an electromagnetic flow meter.

[0028] Please see Figure 2 Step S2: Calculate the mechanical thermal power based on the drive shaft torque and speed, calculate the cooling power based on the inlet and outlet temperatures and flow rates of the cooling medium, and combine the mechanical thermal power and cooling power to obtain the target value of the cooling flow rate.

[0029] The first step is to calculate the mechanical thermal power. The specific calculation process is as follows: based on the rotational speed of the main motor drive shaft at the current moment, the corresponding angular velocity is obtained according to the angular velocity calculation formula.

[0030] Then, the torque and angular velocity of the main motor drive shaft at the current moment are multiplied together to obtain the instantaneous mechanical power value; subsequently, the instantaneous mechanical power value is multiplied by the efficiency coefficient to obtain the mechanical thermal power.

[0031] The efficiency coefficient is a dimensionless number between 0 and 1, which characterizes the proportion of mechanical energy of the drive shaft that is converted into thermal energy in the granulation chamber.

[0032] The efficiency coefficient can be determined through a comparison experiment between no-load and full-load conditions. Specifically, based on a constant-temperature laboratory environment, with no material in the granulation chamber, the cooling system is turned on to the reference flow rate, the main motor drive shaft is idled, and the speed and torque of the main motor drive shaft, as well as the inlet and outlet temperatures of the cooling medium are recorded.

[0033] With a standard batch of material added to the granulation chamber, and the main motor drive shaft speed and reference flow rate being the same as in the no-load test, record the main motor drive shaft torque and the inlet and outlet temperatures of the cooling medium.

[0034] Then, first calculate the difference between the fully loaded mechanical power and the unloaded mechanical power, and then calculate...

[0035] Calculate the difference between the cooling power under full load and the cooling power under no-load conditions. Then, calculate the ratio between the difference in cooling power and the difference in mechanical power to obtain the efficiency coefficient.

[0036] The second step is to calculate the cooling power. The specific calculation process is as follows: calculate the difference between the outlet temperature and the inlet temperature of the cooling medium in the jacket, which is taken as the temperature rise of the cooling medium.

[0037] The cooling power is calculated by multiplying the temperature rise and flow rate of the cooling medium with its specific heat capacity and density. This product represents the amount of heat removed by the cooling medium per unit time. The specific formula for calculating cooling power is as follows: .

[0038] in, Cooling medium volumetric flow rate It should be noted that the flow rate can be either volumetric flow rate or mass flow rate. When using volumetric flow rate, the density of the cooling medium must be considered; however, when using mass flow rate, the density of the cooling medium does not need to be considered. Those skilled in the art can choose according to the actual situation; in this invention, the cooling medium flow rate is selected as the volumetric flow rate of the cooling medium.

[0039] Density of the cooling medium This is the specific heat capacity of the cooling medium; if the cooling medium is water, then... , . Temperature rise of the cooling medium .

[0040] The third step is to obtain the target value of cooling flow rate. The specific process is as follows: first, set the mechanical thermal power to the target heat load that needs to be removed by the cooling system in the granulation chamber.

[0041] Then, based on the cooling power calculation formula and the law of conservation of energy, a heat balance equation is established, making the cooling capacity expression equal to the sum of the target heat load and other heat losses from the granulation chamber to the environment.

[0042] In this invention, the heat balance equation is as follows: .

[0043] in, This represents the theoretical cooling medium flow rate, i.e., the target cooling flow rate. The target heat load is the mechanical heat power.

[0044] Other heat losses include heat dissipation from the granulation chamber to the environment; for granulators with insulation layers but not absolute insulation, there will be a small amount of natural heat dissipation to the environment.

[0045] Considering, It is strongly correlated with the temperature of the granulation chamber, and the temperature of the granulation chamber is mainly determined by... Decide, The larger the particle size, the higher the temperature of the granulation chamber is typically required to maintain a stable material temperature, which in turn leads to a simultaneous increase in other heat losses to the environment. Therefore, this invention will... Set as with They are in a proportional relationship.

[0046] Furthermore, considering that, Too large a temperature will lead to overcooling, while too small a temperature will be insufficient to compensate for environmental heat dissipation, resulting in continuous temperature drift. Therefore, in this invention, by way of example, [the following is used] Set as 5%-10%; as a preferred option, it can be Set as 7%.

[0047] Finally, the heat balance equation is solved to obtain the theoretical cooling medium flow rate. And set it as the target value for cooling flow.

[0048] Please see Figure 3 Step S3: After calculating the target value of cooling flow rate, it needs to be converted into a precise control signal for the execution end of the cooling system, so as to control the cooling system to adjust the cooling medium flow rate in real time according to the target value of cooling flow rate.

[0049] Because the granulation process is dynamic, the viscosity and filling density of the material change, causing the mechanical thermal power to change in real time. Therefore, the required cooling amount, i.e., the target cooling flow rate, is not a fixed value, but an indicator that needs to be calculated and updated in real time. Thus, only after obtaining the target cooling flow rate can the cooling system be adjusted to achieve adaptive dynamic temperature control and ensure stable temperature in the granulation chamber.

[0050] The specific process is as follows: calculate the difference between the target value of cooling flow rate and the instantaneous flow rate of the cooling medium to obtain the real-time control deviation.

[0051] Input the real-time control deviation into a closed-loop controller that includes proportional control; for example... controller or The controller, in this invention, can be selected Controller. A closed-loop controller outputs a control electrical signal.

[0052] Then, the flow regulating valve is driven to adjust the valve opening according to the control electrical signal; for example, the flow rate is changed by adjusting the opening of the electric regulating valve to change the pipeline resistance.

[0053] The change in valve opening is positively correlated with the magnitude of real-time control deviation, meaning that the greater the real-time control deviation, the greater the change in valve opening.

[0054] It is important to note that in closed-loop control, the valve opening is usually not adjusted to the target value all at once, but rather continuously and gradually. The controller continuously drives the valve based on real-time calculated control signals, bringing the actual cooling medium flow rate closer to the target value.

[0055] Finally, the real-time control deviation is continuously reduced through closed-loop control until the instantaneous flow rate of the cooling medium falls within the set allowable error range of the target value of the cooling flow rate, thereby completing the real-time adjustment of the cooling medium flow rate.

[0056] The purpose of setting an allowable error range is to avoid frequent, high-frequency, small-amplitude valve movements near the target cooling flow rate, which could lead to valve wear.

[0057] Considering that if the allowable error range is set too narrowly, even small fluctuations in pipeline pressure or cooling medium temperature will cause the valve to continuously fine-tune, accelerating its wear; if the allowable error range is set too wide, the deviation in cooling medium flow rate may be too large, affecting the accuracy of cooling power calculated based on cooling medium flow rate, thereby disrupting the thermal balance.

[0058] Therefore, in this invention, the allowable error range is exemplarily defined as the target value of the cooling flow rate. - Between. For example, the target cooling flow rate is... Then the allowable error range can be set as follows: .

[0059] Step S4: Calculate the temperature gradient between the torque change rate and the material temperature at key locations. When the torque change rate and temperature gradient satisfy the preset functional relationship, generate a granulation completion signal, and then start the program cooling process to control the cooling system to perform subsequent cooling operations.

[0060] In addressing the fluctuations in mechanical and thermal power caused by changes in material state during granulation, while maintaining thermal balance through real-time adjustment of the cooling medium flow rate, accurately determining the granulation endpoint is equally crucial. Premature termination leads to insufficient particle strength, while premature termination may result in increased energy consumption or even material overheating. To avoid relying on fixed time or a single temperature threshold to determine the granulation endpoint, this invention utilizes the synergistic changes in torque change rate and temperature gradient for comprehensive judgment, ensuring the final granulation quality.

[0061] Step S41: Calculate the torque change rate. The specific process is as follows: First, obtain the torque value sequence of the main motor drive shaft within the sampling period; then, based on the torque value of adjacent sampling times and the corresponding time interval, calculate the change in torque per unit time, and divide the change by the corresponding time interval to obtain the torque change rate at the current moment.

[0062] Then, a moving average filter is applied to the torque change rate at the current moment; for example, a moving average filter with a window size of 5 is used to eliminate high-frequency noise interference; finally, the smoothed torque change rate is output.

[0063] Step S42: Calculate the temperature gradient between material temperatures at key locations. Specifically, this involves obtaining the spatial coordinates of all key locations within the granulation chamber and the material temperature at the same time.

[0064] Then, calculate the temperature difference of the material between any two key locations, and simultaneously calculate the straight-line distance between them using spatial coordinates.

[0065] Then, the temperature difference between the material temperatures is divided by the corresponding straight-line distance to obtain the temperature gradient between the two key locations.

[0066] Considering that the largest temperature gradient can most sensitively reflect the thermal non-uniformity caused by uneven material state or violent reaction within the granulation chamber, the temperature gradient with the largest absolute value among all temperature gradient values ​​is selected as the temperature gradient input to the preset function.

[0067] In this invention, the preset function is specifically as follows: .

[0068] in, Granulation completion rate represents the degree to which the current granulation process is close to completion. It is a dimensionless number between 0 and 1.

[0069] This represents the absolute value of the temperature gradient. This represents the absolute value of the rate of change of torque. , and These are weighting coefficients; all three are greater than zero and their sum is 1.

[0070] The weighting coefficients can be determined as follows: Extract the absolute values ​​of the torque change rate and temperature gradient at the moment of granulation completion of historical qualified batches to form multiple sets of sample data. Using the sample data as independent variables and the value of 1, representing 100% ideal granulation completion, as the dependent variable, perform linear regression fitting using the least squares method. The obtained regression coefficients, after normalization, can be determined as the weighting coefficients.

[0071] when and Simultaneous increases in temperature indicate rapid particle formation and uneven heat distribution within the granulation chamber, resulting in a violent reaction. This typically represents the most intense and critical state of the granulation process. While a single high torque or high temperature gradient might be caused by other disturbances, their simultaneous occurrence provides stronger evidence that granulation is nearing completion. Subsequently, through... This helps improve the accuracy of the obtained granulation completion.

[0072] It is important to note that before using the preset function to obtain the granulation completion rate, it is necessary to... and Normalization is performed to eliminate the influence of dimensions.

[0073] Step S43: Input the absolute value of the torque change rate and the temperature gradient obtained in real time into the preset function, and output the granulation completion degree that represents the current granulation process status from the preset function.

[0074] Among them, the granulation completion degree increases monotonically with the increase of the absolute value of the torque change rate and increases monotonically with the increase of the absolute value of the temperature gradient.

[0075] When the granulation completion index reaches and remains above the preset completion threshold for a set duration for the first time, it is determined that the preset function relationship is satisfied, and then the control system generates a granulation completion signal.

[0076] The preset completion threshold can be determined based on historical data. For example, by statistically analyzing the granulation completion rate of 100 batches of qualified granules, the mean is 0.82 and the standard deviation is 0.03. In order to ensure coverage of 90% of qualified batches and avoid false triggering, the preset completion threshold is set to the mean + 1 standard deviation, i.e., 0.85.

[0077] The sampling duration can be set to 3 sampling periods to prevent accidental triggering due to instantaneous fluctuations. For example, when the sampling period is 0.2 seconds, which is high-frequency sampling, a sampling duration of 0.6 seconds is sufficient to filter out instantaneous interference such as mechanical vibration.

[0078] After granulation, the temperature of the granulation chamber and the material is usually high. If cooling is stopped immediately or the temperature drops too rapidly, the formed granules may crack or deform due to thermal stress, or condensation may occur due to the sudden cooling of the granulation chamber, affecting the final moisture content and quality of the product. Therefore, this invention introduces a gentle and controlled programmed cooling process to ensure that the product safely transitions to the discharge temperature.

[0079] Step S44: After generating the granulation completion signal, start the program cooling process. First, divide the target cooling flow rate into several adjustment stages and sort them in ascending order of flow rate.

[0080] For example, the target cooling flow rate can be divided into 5 adjustment stages. , , , , .

[0081] Then, each adjustment stage is executed sequentially according to the order. For each adjustment stage, the control cooling system increases the cooling medium flow rate to the corresponding flow rate and maintains a complete sampling cycle in order to collect enough temperature data to evaluate the adjustment effect of the cooling medium flow rate of that adjustment stage.

[0082] At the end of each sampling period, the material temperature at all key locations is acquired; if the material temperature at all key locations shows a downward trend during the sampling period, the process proceeds to the next adjustment stage; otherwise, the current adjustment stage is maintained.

[0083] The above-mentioned judgment method is adopted to prevent excessively rapid cooling from causing the material to shrink too quickly or causing stress impact on the granulation equipment. If the material temperature at any critical location does not decrease or increases, it indicates that the current cooling intensity may have reached the critical point or the cooling is uneven. Blindly increasing the cooling may cause the granules to crack due to thermal stress. It is necessary to maintain the current stage and continue to observe to prevent excessively rapid cooling or local overcooling.

[0084] After all the regulating stages have been completed, if the valve is suddenly closed, the temperature may rebound due to residual heat from the granulation equipment itself or ambient heat. Therefore, it is necessary to switch to a flow reduction stage to gradually reduce the cooling intensity after the active cooling is completed.

[0085] During the flow rate decrease phase, each adjustment stage is executed sequentially in descending order of flow rate, and each adjustment stage maintains a complete sampling period.

[0086] If the material temperature at any critical location shows an upward trend during the sampling cycle, the process will revert to the previous adjustment stage, run one sampling cycle, and then attempt to enter the current adjustment stage again.

[0087] If a rise in material temperature is detected during the reduction of cooling medium flow rate, it indicates that the reduction in cooling intensity is too rapid, and the system's own residual heat exceeds the current cooling capacity. In this case, reverting to the previous adjustment stage, i.e., the stage with a higher flow rate, constitutes negative feedback correction, ensuring that the temperature of the granulation chamber and material does not rebound when the cooling load is reduced.

[0088] It should be noted that a downward trend can be determined by calculating that the slope of the linear regression of the temperature sequence within the corresponding sampling period is negative, or by determining whether the temperature of the last two sampling points within the sampling period shows a continuous decrease. Similarly, an upward trend can be determined, which indicates a temperature rise, possibly due to excessively rapid cooling causing the material to absorb moisture and release heat.

[0089] When the number of sampling periods continuously maintained in any adjustment stage reaches the preset upper limit, the system is forced to enter the next adjustment stage to avoid dead loops.

[0090] To ensure stable cooling while preventing a dead loop due to occasional fluctuations or minor deviations at key locations, and to ensure the final completion of the cooling process, a preset upper limit can be set to 5 sampling periods in this invention. For example, with a sampling period of 0.2 seconds and a preset upper limit of 1.0 second, effective temperature changes can be observed within this duration.

[0091] After the sampling cycle of the last regulating stage in the flow reduction phase ends, the active regulation of the cooling medium flow rate is stopped, and the cooling operation is completed.

[0092] Step S5: Record the moment when the torque change rate first falls below the baseline change rate, the maximum value of the temperature gradient, and the cumulative value of mechanical thermal power during the granulation process of each batch.

[0093] Considering that different batches of spirulina powder have certain differences in particle size, moisture content, etc., recording key process parameters, such as torque change rate and maximum temperature gradient, can provide historical data reference benchmarks for subsequent batches. This is a prerequisite for achieving continuous optimization between batches and adjusting cooling strategies in advance based on historical data.

[0094] It should be noted that the baseline rate of change can be determined as follows: Analyze at least 100 batches of qualified products and find that the torque change rate at the end of granulation is basically stable between -0.02 and -0.04. Then, the baseline rate of change can be determined based on the mean standard deviation of all torque change rates at the end of granulation. Within the range of times, the benchmark rate of change is taken as -0.03.

[0095] Please see Figure 4 Step S6: Based on the recorded historical data, before the start of the next batch of granulation, if the torque change rate of the current batch at a certain moment is greater than the average value of the historical batches at the same moment, then increase the target value of cooling flow rate under the same mechanical thermal power conditions.

[0096] If the granulation reaction of the material is more vigorous, it will manifest as a torque change rate higher than the historical average at a certain moment, meaning that more heat is generated per unit time or the granulation speed is faster. If the original cooling strategy is still used, it may lead to insufficient cooling and excessive temperature.

[0097] By comparing the data of the current batch with that of historical batches at the same time, the cooling strategy can be adjusted in advance, that is, the cooling medium flow rate can be proactively increased to adapt to the differences between batches of different materials, prevent temperature runaway, and achieve continuous optimization between batches, thereby improving the accuracy and practicality of spirulina powder granulation temperature monitoring and control.

[0098] The specific process is as follows: before the start of the next batch of granulation, if the torque change rate of the current batch at a certain moment is greater than the average value of the historical batches at the same moment, then the ratio of the torque change rate of the current batch at a certain moment to the average value of the historical batches at the same moment is taken as the first ratio.

[0099] Simultaneously, the average material temperature at each key location at the current moment is obtained. If the average material temperature is greater than the average temperature of historical batches at the same time, the ratio of the average material temperature to the average temperature of historical batches at the same time is used as the second ratio.

[0100] Select the larger of the first ratio and the second ratio as the correction factor; otherwise, use the first ratio as the correction factor.

[0101] Then, the correction factor is multiplied by the mechanical thermal power at the current moment to obtain the equivalent thermal load.

[0102] Finally, in the heat balance equation, the equivalent heat load is used to replace the original mechanical heat power, and the solution is recalculated with the cooling medium flow rate as the only variable, resulting in an increased cooling medium flow rate.

[0103] In summary, this invention achieves real-time adjustment of the cooling medium flow rate by simultaneously collecting torque, rotational speed, temperature, and flow rate parameters, and integrating the calculation of mechanical thermal power and cooling power to maintain thermal balance during the granulation process. Furthermore, by analyzing the synergistic relationship between torque change rate and temperature gradient, it accurately determines the granulation endpoint and initiates a tiered cooling process upon determination, ensuring product quality after granulation. Simultaneously, by recording key parameters for each batch, the cooling strategy is dynamically adjusted in subsequent batches based on historical data. This achieves dynamic maintenance of thermal balance during granulation, accurate identification of the granulation endpoint, controlled execution of the cooling process, and feedforward optimization of the cooling strategy based on historical data, thus realizing the goal of full-process temperature monitoring and control.

[0104] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0105] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0106] In addition, the functional modules in the various embodiments of the present invention can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0107] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0108] Finally, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A spirulina powder granulation temperature monitoring control method, characterized by, Includes the following steps: The material temperature, drive shaft torque and speed of the main motor, and inlet and outlet temperatures and flow rates of the jacket cooling medium at key locations inside the granulation chamber are collected simultaneously. By integrating the mechanical thermal power calculated from the drive shaft torque and speed, and the cooling power calculated from the inlet and outlet temperatures and flow rates of the cooling medium, the target value of the cooling flow rate is finally obtained. The cooling system is controlled to adjust the cooling medium flow rate in real time according to the target cooling flow rate; Calculate the temperature gradient between the torque change rate and the material temperature at key locations. When the torque change rate and the temperature gradient satisfy the preset functional relationship, generate a granulation completion signal, then start the program cooling process and control the cooling system to perform subsequent cooling operations. Record the moment when the torque change rate first falls below the baseline change rate, the maximum value of the temperature gradient, and the cumulative value of mechanical thermal power during the granulation process of each batch; Before the start of the next batch of granulation, if the torque change rate of the current batch at a certain moment is greater than the average value of the historical batches at the same moment, the target value of cooling flow rate will be increased under the same mechanical thermal power conditions.

2. The spirulina powder granulation temperature monitoring control method according to claim 1, characterized in that, The process of obtaining the mechanical thermal power is as follows: Based on the current rotational speed of the main motor drive shaft, the corresponding angular velocity is obtained according to the angular velocity calculation formula; Multiply the torque and angular velocity of the main motor drive shaft at the current moment to obtain the instantaneous value of mechanical power; The mechanical thermal power is obtained by multiplying the instantaneous value of mechanical power by the efficiency coefficient, which characterizes the proportion of mechanical energy converted into heat energy.

3. The spirulina powder granulation temperature monitoring control method according to claim 1, characterized in that, The process of obtaining the cooling power is as follows: Calculate the difference between the outlet temperature and the inlet temperature of the cooling medium in the jacket, and use this as the temperature rise of the cooling medium; The cooling power is calculated by multiplying the temperature rise and flow rate of the cooling medium with its specific heat capacity and density. This product represents the amount of heat carried away by the cooling medium per unit time.

4. The spirulina powder granulation temperature monitoring control method according to claim 1, characterized in that, The process of combining the mechanical thermal power and cooling power to obtain the target value of cooling flow rate is as follows: Set the mechanical thermal power to the target thermal load that needs to be removed by the cooling system within the granulation chamber; Based on the law of conservation of energy, a heat balance equation is established to make the cooling power equal to the sum of the target heat load and other heat losses from the granulation chamber to the environment; Solve the heat balance equation to obtain the theoretical cooling medium flow rate, and set it as the target value for the cooling flow rate.

5. The spirulina powder granulation temperature monitoring control method according to claim 1, characterized in that, The cooling system is controlled to adjust the cooling medium flow rate in real time according to the target cooling flow rate, specifically as follows: The difference between the target cooling flow rate and the instantaneous flow rate of the cooling medium is calculated to obtain the real-time control deviation. The real-time control deviation is input to a closed-loop controller that includes proportional control, and the closed-loop controller outputs a control electrical signal. The valve opening is adjusted by driving the actuator of the flow regulating valve according to the control electrical signal. The change in valve opening is positively correlated with the magnitude of the real-time control deviation. By continuously reducing the real-time control deviation through closed-loop control until the instantaneous flow rate of the cooling medium falls within the set allowable error range of the target cooling flow rate, the real-time adjustment of the cooling medium flow rate is completed.

6. The spirulina powder granulation temperature monitoring control method according to claim 1, characterized by, The process of calculating the torque change rate is as follows: Obtain the torque value sequence of the main motor drive shaft within the sampling period; Based on the torque values ​​at adjacent sampling times and the corresponding time intervals, the change in torque per unit time is calculated. Divide the change by the corresponding time interval to obtain the torque change rate at the current moment; Apply a moving average filter to the current torque change rate and output a smoothed torque change rate.

7. The spirulina powder granulation temperature monitoring control method according to claim 1, characterized by, The temperature gradient between the material temperatures at the key locations is calculated as follows: Obtain the spatial coordinates of all key locations within the granulation chamber and the material temperature at the same time. Calculate the temperature difference of the material between any two key locations, and at the same time, calculate the straight-line distance between them using spatial coordinates; Divide the temperature difference of the materials by the corresponding straight-line distance to obtain the temperature gradient between the two key locations; Select the temperature gradient with the largest absolute value from all temperature gradient values ​​as the temperature gradient input to the preset function.

8. The spirulina powder granulation temperature monitoring control method according to claim 1, characterized by, A granulation completion signal is generated when the torque change rate and temperature gradient satisfy a preset functional relationship. Specifically: The absolute value of the torque change rate and the temperature gradient obtained in real time are input into a preset function; the preset function outputs the granulation completion degree, which represents the current granulation process status; wherein, the granulation completion degree increases monotonically with the increase of the absolute value of the torque change rate and increases monotonically with the increase of the absolute value of the temperature gradient. When the granulation completion index reaches and remains above the preset completion threshold for a set duration for the first time, it is determined that the preset function relationship is satisfied, and then the control system generates a granulation completion signal.

9. The method according to claim 8, wherein the temperature of the granulation of the spirulina powder is monitored and controlled. The process of controlling the cooling system to perform subsequent cooling operations is as follows: After generating the granulation completion signal, the program cooling process is started, the target value of cooling flow rate is divided into several adjustment stages, and sorted by flow rate from smallest to largest; Each adjustment stage is executed sequentially according to the order. Each time an adjustment stage is executed, the cooling system is controlled to increase the flow rate of the cooling medium to the corresponding flow rate and maintain it for a complete sampling cycle. At the end of each sampling period, acquire the material temperature at all key locations; if the material temperature at all key locations shows a downward trend during the sampling period, proceed to the next adjustment stage; otherwise, maintain the current adjustment stage. After all regulation stages are completed, the flow rate decrease phase begins. Each regulation stage is executed sequentially in descending order of flow rate, and each regulation stage is maintained for one complete sampling period. During the flow rate reduction phase, if the material temperature at any critical location shows an upward trend during the sampling cycle, the process will revert to the previous regulation stage, run for one sampling cycle, and then attempt to enter the current regulation stage again. When the number of consecutive sampling periods maintained in any adjustment stage reaches the preset upper limit, the system is forced to enter the next adjustment stage. After the sampling cycle of the last adjustment stage in the flow reduction phase ends, the active adjustment of the cooling medium flow rate stops, and the cooling operation is completed.

10. The method for monitoring and controlling the granulation temperature of spirulina powder according to claim 1, characterized in that, To increase the target value of cooling flow rate under the same mechanical thermal power conditions, specifically: When the torque change rate of the current batch at a certain moment is greater than the average value of the historical batches at the same moment, the ratio of the former to the latter is calculated and used as the first ratio. Obtain the average material temperature at each key location at the current moment; if the average material temperature is greater than the average of the same historical batch at the same moment, calculate the ratio of the former to the latter as the second ratio, and select the larger of the first ratio and the second ratio as the correction factor. Otherwise, the first ratio is used as a correction factor; Multiply the correction factor by the mechanical thermal power at the current moment to obtain the equivalent heat load; In the heat balance equation, the equivalent heat load is used to replace the original mechanical heat power, and the solution is recalculated with the cooling medium flow rate as the only variable, resulting in an increased cooling medium flow rate.

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