CN-121326040-B - Spirulina powder granulating temperature monitoring control method

CN121326040BCN 121326040 BCN121326040 BCN 121326040BCN-121326040-B

Abstract

The invention relates to the technical field of pelletization production monitoring, in particular to a spirulina powder pelletization temperature monitoring control method. According to the invention, by synchronously collecting the parameters of torque, rotation speed, temperature and flow, and integrating and calculating the mechanical thermal power and the cooling power, the real-time adjustment of the flow of the cooling medium is realized, so that the thermal balance in the granulating process is maintained. According to the invention, through analyzing the cooperative relation between the torque change rate and the temperature gradient, the accurate judgment of the granulating completion end point is realized, the misjudgment caused by depending on fixed time or a single temperature threshold value is avoided, the material overheating caused by insufficient particle strength or too late ending due to early ending is effectively prevented, and the molding quality of the spirulina powder active ingredient and particles is ensured.

Inventors

CHEN FUGANG
Lei Xuexiang
CHEN MIN

Assignees

青岛固德励健生物技术有限公司

Dates

Publication Date: 20260512
Application Date: 20251203

Claims (10)

1. The spirulina powder granulating temperature monitoring and controlling method is characterized by comprising the following steps: synchronously collecting the material temperature at key positions in the granulating cavity, the torque and the rotating speed of a driving shaft of a main motor, and the inlet and outlet temperatures and the flow rates of jacket cooling media; Combining mechanical heat power calculated by the torque and the rotating speed of the driving shaft and cooling power calculated by the inlet and outlet temperatures and the flow of the cooling medium to finally obtain a cooling flow target value; controlling the cooling system to adjust the flow of the cooling medium in real time according to the target value of the cooling flow; Calculating the torque change rate and the temperature gradient between the material temperatures at key positions, generating a pelletization completion signal when the torque change rate and the temperature gradient meet a preset functional relation, then starting a program cooling flow, and controlling a cooling system to execute subsequent cooling operation; recording the moment when the torque change rate is lower than the reference change rate for the first time in the granulating process of each batch, the maximum value of the temperature gradient and the accumulated value of the mechanical thermal power; before the next batch granulation starts, if the torque change rate of the current batch at a certain moment is larger than the average value of the historical batch at the same moment, the cooling flow target value is increased under the same mechanical heat power condition.
2. The spirulina powder granulation temperature monitoring and controlling method according to claim 1, wherein the mechanical thermal power obtaining process is as follows: Based on the rotating speed of the driving shaft of the main motor at the current moment, obtaining a corresponding angular speed according to an angular speed calculation formula; Multiplying the torque and the angular speed of the driving shaft of the main motor at the current moment to be used as a mechanical power instantaneous value; And multiplying the mechanical power instantaneous value by an efficiency coefficient representing the proportion of the mechanical energy converted into heat energy to obtain mechanical thermal power.
3. The spirulina powder granulation temperature monitoring and controlling method according to claim 1, wherein the cooling power obtaining process is as follows: Calculating the difference between the outlet temperature and the inlet temperature of the jacket cooling medium to be used as the temperature rise of the cooling medium; And (3) carrying out product calculation according to the temperature rise and the flow of the cooling medium and combining the specific heat capacity and the density of the cooling medium to obtain the heat taken away by the cooling medium in unit time, namely the cooling power.
4. The spirulina powder granulation temperature monitoring and controlling method according to claim 1, wherein the process of fusing the mechanical thermal power and the cooling power to obtain the cooling flow target value is as follows: Setting the mechanical thermal power to a target thermal load within the pelletization cavity that needs to be removed by the cooling system; Based on the law of conservation of energy, a heat balance equation is established, so that the cooling power is equal to the sum of the target heat load and other heat loss of the granulating cavity for radiating heat to the environment; And solving a heat balance equation to obtain a theoretical cooling medium flow, and setting the theoretical cooling medium flow as a cooling flow target value.
5. The spirulina powder pelletization temperature monitoring control method according to claim 1, wherein the cooling system is controlled to adjust the flow of the cooling medium in real time according to the target value of the cooling flow, specifically: Calculating the difference between the target value of the cooling flow and the instantaneous flow of the cooling medium to obtain a real-time control deviation; Inputting the real-time control deviation into a closed-loop controller with a proportional control function, and outputting a control electric signal by the closed-loop controller; driving the flow regulating valve executing end to regulate the valve opening according to the control electric signal, wherein the variation of the valve opening is positively correlated with the magnitude of the real-time control deviation; And continuously reducing the real-time control deviation through closed-loop control until the instantaneous flow of the cooling medium falls into the set allowable error interval of the target value of the cooling flow, thereby completing the real-time adjustment of the flow of the cooling medium.
6. The spirulina powder granulation temperature monitoring and controlling method according to claim 1, wherein the process of calculating the torque change rate is: Acquiring a torque value sequence of a driving shaft of a main motor in a sampling period; calculating the change amount of the torque in unit time based on the torque values of adjacent sampling moments and corresponding time intervals; dividing the variation by the corresponding time interval to obtain the torque variation rate at the current moment; And carrying out moving average filtering on the torque change rate at the current moment, and outputting the smoothed torque change rate.
7. The spirulina powder granulation temperature monitoring and controlling method according to claim 1, wherein the calculating of the temperature gradient between the material temperatures at the key positions is specifically: acquiring space coordinates of all key positions in the granulating cavity and material temperature at the same time; Calculating the difference value of the material temperature between any two key positions, and simultaneously calculating the linear distance between the two key positions by combining with the space coordinates; dividing the difference value of the material temperature by the corresponding linear distance to obtain a temperature gradient between the two key positions; and selecting the temperature gradient with the largest absolute value from all the temperature gradient values as an input preset function.
8. The spirulina powder pelletization temperature monitoring control method according to claim 1, wherein the pelletization completion signal is generated when the torque change rate and the temperature gradient satisfy a preset function relation, specifically: The method comprises the steps of inputting a torque change rate absolute value and a temperature gradient obtained in real time into a preset function, outputting a granulating completion degree representing the current granulating process state by the preset function, wherein the granulating completion degree monotonically increases along with the increase of the torque change rate absolute value and monotonically increases along with the increase of the temperature gradient absolute value; when the pelletization completion index reaches and is maintained above a preset completion threshold for the first time and reaches a set duration, the preset functional relation is judged to be met, and then a pelletization completion signal is generated by the control system.
9. The spirulina powder granulation temperature monitoring and controlling method according to claim 8, wherein the cooling system is controlled to execute the following cooling operation: After the granulating completion signal is generated, starting a program cooling flow, dividing a cooling flow target value into a plurality of adjusting stages, and sequencing from small to large according to the flow; sequentially executing each adjusting stage according to the sequence, and controlling the cooling system to lift the flow of the cooling medium to the corresponding flow and maintaining a complete sampling period when executing one adjusting stage; acquiring material temperatures of all key positions at the end of each sampling period, entering a next adjusting stage if the material temperatures of all key positions in the sampling period are in a descending trend, otherwise, maintaining the current adjusting stage; After all the regulation stages are executed, switching to a flow decreasing stage, and sequentially executing all the regulation stages according to the sequence from the large flow to the small flow, wherein each regulation stage maintains a complete sampling period; In the flow decreasing stage, if the material temperature of any key position in the sampling period is in an ascending trend, returning to the previous adjusting stage, and after one sampling period is operated, trying to enter the current adjusting stage; when the number of sampling periods continuously maintained by any adjusting stage reaches a preset upper limit, the next adjusting stage is forced to enter; And stopping actively regulating the flow of the cooling medium after the sampling period of the last regulating stage in the flow decreasing stage is ended, and completing the cooling operation.
10. The spirulina powder granulation temperature monitoring and controlling method according to claim 1, wherein the cooling flow target value is increased under the same mechanical thermal power condition, specifically: When the torque change rate of a current batch at a certain moment is larger than the average value of the historical batches at the same moment, calculating the ratio of the current batch to the historical batch as a first ratio; If the average value of the material temperature is larger than the average value of the historical batch at the same time, calculating the ratio of the former to the latter as a second ratio, and selecting the largest of the first ratio and the second ratio as a correction factor; multiplying the correction factor by the mechanical thermal power at the current moment to obtain an equivalent thermal load; In the heat balance equation, the equivalent heat load is used for replacing the original mechanical heat power, and the cooling medium flow is used as the only variable for solving again, so that the increased cooling medium flow is obtained.

Description

Spirulina powder granulating temperature monitoring control method Technical Field The invention relates to the technical field of granulation production monitoring temperature regulation and control, in particular to a spirulina powder granulation temperature monitoring and controlling method. Background A typical production process for granulating spirulina powder mainly comprises the steps of raw material pretreatment and mixing, tempering, granulating, drying, cooling, screening and packaging. In the whole process chain, a granulating step is taken as a core process, and the purpose is to enable the quenched and tempered materials to be molded into granules through a ring die hole through compression roller extrusion. In the process, the materials, the annular mold and the compression roller can generate heat through intense friction, and meanwhile, the temperature of the materials can be raised due to the combination of the waste heat of the tempering link, so that the process is a passive and continuous heat generation process. The spirulina powder is used as a heat-sensitive material, and the temperature control in the granulating process is important. Too high a temperature may result in loss of high active ingredients such as protein, phycocyanin, etc., while too low a temperature may result in insufficient particle formation and insufficient strength. However, the control of the granulating temperature in the prior art mainly depends on preset adjustment of the conditioning temperature and the prepositive parameters of the water content of the materials, and indirect and delayed heat dissipation is carried out by introducing cooling water into the jacket of the granulator. The dynamic change of the temperature in the granulating cavity cannot be quantized in the mode, so that the cooling system is delayed in response and poor in effect, dynamic balance between heat generation and heat dissipation is difficult to realize, the granulating and forming quality of the spirulina powder is affected, and the consistency of the forming quality among batch granulating is affected. Disclosure of Invention The invention aims to overcome the defects of the prior art, and by synchronously acquiring mechanical and thermodynamic parameters in the granulating process and fusing and calculating mechanical heat power and cooling power in real time to obtain a cooling medium flow target value, the invention realizes dynamic and accurate temperature control, further intelligently judges the granulating completion end point by integrating the torque change rate and the temperature gradient, adopts a program cooling flow, and ensures the shaping quality and the consistency of the quality of the spirulina powder granulating. The technical scheme includes that the spirulina powder granulating temperature monitoring and controlling method comprises the following steps of synchronously collecting material temperature at key positions in a granulating cavity, driving shaft torque and rotating speed of a main motor, and inlet and outlet temperatures and flow rates of jacket cooling media. And the cooling system is controlled to regulate the flow of the cooling medium according to the cooling flow target value in real time. Calculating the torque change rate and the temperature gradient between the material temperatures at key positions, generating a pelletization completion signal when the torque change rate and the temperature gradient meet a preset functional relation, then starting a program cooling flow, and controlling a cooling system to execute subsequent cooling operation. The moment when the torque change rate is lower than the reference change rate for the first time in the granulation process of each batch, the maximum value of the temperature gradient and the accumulated value of the mechanical heat power are recorded. Before the next batch granulation starts, if the torque change rate of the current batch at a certain moment is larger than the average value of the historical batch at the same moment, the cooling flow target value is increased under the same mechanical heat power condition. Compared with the prior art, the invention has the following beneficial effects that 1, the invention realizes the real-time adjustment of the flow of the cooling medium by synchronously collecting the parameters of torque, rotating speed, temperature and flow and integrating and calculating the mechanical thermal power and the cooling power so as to maintain the thermal balance in the granulating process. 2. According to the invention, through analyzing the cooperative relation between the torque change rate and the temperature gradient, the accurate judgment of the granulating completion end point is realized, the misjudgment caused by depending on fixed time or a single temperature threshold value is avoided, the material overheating caused by insufficient particle strength or too late ending due to early ending is effective