Beer pasteurization steam flow dynamic regulation method and system based on stirring current

Abstract

The application discloses a beer gelatinization steam flow dynamic regulation method and system based on stirring current. The method comprises the following steps: acquiring a real-time current value of a stirring motor; determining a real-time viscosity of gelatinized mash according to the real-time current value and a preset function relationship between current and viscosity; determining a maximum steam pressure allowed at the current viscosity according to the real-time viscosity, wherein the maximum steam pressure decreases with the increase of the real-time viscosity and increases with the decrease of the real-time viscosity; calculating a target steam flow according to the maximum steam pressure and a preset function relationship between steam pressure and steam flow; and adjusting the opening degree of a steam regulating valve according to the target steam flow. The application indirectly represents the viscosity of the mash through the stirring current, restricts the maximum steam pressure by the viscosity, realizes the precise delivery of the minimum steam, can effectively avoid local overheating and coking, reduce steam consumption and shorten the gelatinization time, and does not need an additional online viscosity meter, and is suitable for the gelatinization process of rice, starch and other materials.

Description

Technical Field

[0001] This invention belongs to the field of beer brewing and processing technology, specifically relating to a method and system for dynamic control of beer gelatinization steam flow based on stirring current. Background Technology

[0002] The gelatinization pot is one of the core pieces of equipment in the saccharification workshop, mainly used for gelatinizing malt or starch. Its structure primarily includes the pot body, steam jacket, washing ball, stirring paddle, coils, and temperature sensors. The gelatinization pot mainly gelatinizes the starch in raw materials such as rice or starch, providing fermentable sugars for subsequent saccharification. Its main mechanism is that after heating to a certain temperature, starch granules absorb water, swell, and rupture, forming a paste-like solution. However, excessively rapid heating can lead to localized overheating and scorching, causing enzyme inactivation; excessively slow heating prolongs the production cycle and reduces the utilization rate of other equipment. Traditional steam flow control of the heating rate relies on manual experience, resulting in lag and fluctuations. Furthermore, the raw materials themselves do not contain enzymes; the gelatinization process requires crushing the enzymes from the malt or adding external enzyme preparations for decomposition, leading to temperature fluctuations during gelatinization. Therefore, temperature control in the gelatinization pot is crucial; excessively high temperatures will prematurely destroy enzyme activity, while excessively low temperatures will result in incomplete gelatinization or a slow gelatinization rate.

[0003] In existing beer gelatinization processes, temperature is considered the only controlled variable: a temperature probe is inserted in the middle of the pot, and the signal, after PID calculation, drives a steam diaphragm valve. As long as the measured temperature is lower than the set curve, the valve remains open. However, starch gelatinization is a drastic phase transition process with a sharp increase in viscosity and a sudden increase in fluid resistance. Before the mash around the probe reaches the target temperature, the bottom of the pot and the walls of the coils have already overheated due to increased viscosity and decreased flow rate. Local instantaneous overheating can reach 5-7°C, which wastes steam and triggers the Maillard reaction, producing a difficult-to-clean brown coking layer.

[0004] To mitigate the impact of temperature hysteresis, improved solutions such as dual-parameter control (temperature + time), model predictive control (MPC), and online viscometers have emerged in recent years. MPC, by establishing a gelatinization kinetic model, can provide valve opening compensation in advance, but model mismatch is severe when there are fluctuations in raw material protein content and particle size. While online viscometers can directly measure flow resistance, the high maintenance costs of rotary bearing equipment mean that most companies still resort to the old approach of "increasing the safety margin": increasing the initial water ratio and extending the heating time, which ultimately lowers the saccharification yield.

[0005] During the gelatinization process of corn starch, the viscosity increases significantly during the gelation stage. In the heating stage, the steam flow rate and pressure are often mismatched, resulting in low heat exchange efficiency and local overheating of the gelatinized mash, which can lead to coking.

[0006] Therefore, there is an urgent need for a dynamic steam control method for the gelatinization process that can avoid local overheating and coking, increase the heating rate, reduce steam energy consumption, and does not rely on expensive online viscometers and complex models. Summary of the Invention

[0007] To solve at least one of the above-mentioned technical problems, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for dynamically controlling the flow rate of beer gelatinization steam based on stirring current, comprising the following steps: Obtain the real-time current value of the stirring motor; The real-time viscosity of the gelatinized mash is determined based on the real-time current value and the preset functional relationship between current and viscosity. Based on the real-time viscosity, determine the maximum allowable vapor pressure at the current viscosity, wherein the maximum vapor pressure decreases as the real-time viscosity increases and increases as the real-time viscosity decreases. Calculate the target steam flow rate based on the maximum steam pressure and the preset functional relationship between steam pressure and steam flow rate; Adjust the opening of the steam regulating valve according to the target steam flow rate to dynamically control the steam supply.

[0008] Furthermore, the real-time current value of the stirring motor is obtained, specifically by: using a current sensor to collect the current signal of the stirring motor, and performing low-pass filtering on the current signal to filter out high-frequency noise and output a smooth real-time current value.

[0009] Furthermore, the preset functional relationship between current and viscosity is as follows: , Where I is the real-time current value of the stirring motor, I0 is the current value when the viscosity of the gelatinized mash approaches zero, K is the equipment constant, μ is the real-time viscosity of the gelatinized mash, and n is the exponent. In the laminar flow state at the initial stage of gelatinization, the exponent n=1.

[0010] Furthermore, the process of establishing the functional relationship between steam pressure and steam flow rate in advance also includes a sub-step of calibrating the optimal motor speed opening: During the gelatinization heating stage, multiple different motor speed opening percentages were set, namely 70%, 80%, and 90%. Steam flow and steam pressure data were collected synchronously at each opening degree; the pressure fluctuation amplitude, flow response time and unit steam heat consumption were analyzed at each opening degree. The optimal motor speed opening is selected based on the smallest pressure fluctuation amplitude, the shortest flow response time, and the lowest unit steam heat consumption. Further, the optimal motor speed opening is 80%.

[0011] Furthermore, at the optimal motor speed opening, the speed opening is kept fixed, and multiple sets of measured data of steam pressure and steam flow are collected synchronously at a fixed period. A functional relationship model between steam pressure and steam flow rate was obtained by fitting the collected measured data.

[0012] Furthermore, the preset functional relationship between steam pressure and steam flow rate is as follows: , Among them, Q s C represents the steam mass flow rate. d Where A is the flow coefficient, A is the effective cross-sectional area of ​​the flow channel, and P is the absolute pressure of the steam. b Let P be the back pressure, and ρ(P) be the saturated vapor density function.

[0013] Furthermore, the saturated steam density function ρ(P) is approximately expressed as follows when the absolute steam pressure P is in the range of 1 bar to 15 bar: , C d A was experimentally calibrated to 15650, which serves as a theoretical synthesis constant, and the back pressure P... b The pressure is much smaller than the absolute steam pressure P, thus yielding a simplified functional relationship between steam pressure and steam flow rate: .

[0014] Furthermore, the maximum permissible vapor pressure at the current viscosity is determined based on the real-time viscosity, specifically including: The maximum steam pressure is pre-calibrated in the following manner: At the current viscosity, the steam pressure is adjusted in a stepwise manner, and the measured steam pressure and measured steam flow rate are read online at each pressure point; Based on the functional relationship between steam pressure and steam flow rate, the measured comprehensive constant C can be deduced. d A 测； The measured comprehensive constant C d A 测 The measured comprehensive constant is compared with the theoretical comprehensive constant. When the ratio of the measured comprehensive constant to the theoretical comprehensive constant is lower than a preset threshold, it is determined that the heat exchange efficiency has decreased significantly, and the current pressure point is taken as the maximum steam pressure at this viscosity. The above calibration steps were performed for different viscosities to establish a mapping relationship between viscosity and maximum vapor pressure. Furthermore, a preset threshold of 90% was set.

[0015] Furthermore, it also includes a current trend monitoring step: The real-time current value is compared with the preset normal current threshold range; If the current shows a continuous upward trend within three consecutive sampling periods, or the current increase exceeds 10%, it is determined to be an abnormal current trend. When an abnormal current trend is detected, the steam flow adjustment amount is calculated based on the current deviation through the PID controller, the target flow increment is generated, and the opening of the steam regulating valve is updated accordingly; the normal current threshold range is preset based on historical stable operation data.

[0016] Furthermore, it also includes a stress coordination monitoring step: Real-time acquisition of the actual pressure of the steam system; Calculate the theoretical pressure corresponding to the current steam flow rate based on the functional relationship between steam pressure and steam flow rate. The actual pressure is compared with the theoretical pressure. If the relative deviation between the actual pressure and the theoretical pressure exceeds 5%, an early warning signal is triggered, and the further increase in steam flow is limited.

[0017] Furthermore, when two or more viscosity peaks occur during the gelatinization process, the determination of the maximum steam pressure and the calculation of the target steam flow rate are performed independently for each viscosity peak stage to achieve multi-stage segmented dynamic control.

[0018] Furthermore, the determination of the maximum steam pressure and the calculation of the target steam flow rate are repeated every 30 seconds.

[0019] Furthermore, adjusting the opening degree of the steam regulating valve according to the target steam flow rate specifically includes: The target steam flow rate is used as the set value, and the steam flow rate measured by the steam flow meter is used as the feedback value, which is then input into the PID controller. The PID controller outputs a control signal to the valve positioner of the steam regulating valve based on the deviation between the set value and the feedback value. The valve positioner drives a pneumatic diaphragm or piston to generate thrust based on the control signal, which drives the valve stem to move up and down, causing the valve core to shift, thereby adjusting the steam flow area and making the measured steam flow rate approach the target steam flow rate.

[0020] Secondly, the present invention also provides a dynamic control system for steam flow in a gelatinization process based on stirring current, characterized in that it includes: A gelatinization pot is used to hold raw materials and carry out a gelatinization reaction. The stirring system includes a stirring paddle and a drive motor disposed in the gelatinization pot; The heating system, including steam pipes, a jacket, and an inner heating ring, is used to provide heat to the gelatinization pot; A current sensor is installed in the circuit of the drive motor to collect the current signal of the stirring motor in real time. A steam flow meter is installed on a steam pipeline to detect the steam flow rate. A pressure sensor, installed within the steam system, is used to detect steam pressure; A steam regulating valve, installed on a steam pipeline, is used to regulate the steam flow rate according to the target steam flow rate; A valve positioner, connected to the steam regulating valve, is used to receive control signals and drive the steam regulating valve to operate; The control unit is electrically connected to the current sensor, steam flow meter, pressure sensor, steam regulating valve, and valve positioner, respectively. The control unit is configured to: determine a real-time current value based on the current signal collected by the current sensor; determine the real-time viscosity of the gelatinized mash based on the real-time current value and a preset functional relationship between current and viscosity; determine the maximum allowable steam pressure at the current viscosity based on the real-time viscosity and according to the rule that the maximum steam pressure decreases as the real-time viscosity increases; calculate the target steam flow rate based on the maximum steam pressure and a preset functional relationship between steam pressure and steam flow rate; and control the opening of the steam regulating valve based on the target steam flow rate.

[0021] Furthermore, the control unit is pre-configured with: A functional relationship model between current and viscosity is used to convert the collected real-time current value of the stirring motor into real-time viscosity. The functional relationship model is as follows: , A functional relationship model between steam pressure and steam flow rate, wherein the functional relationship model is as follows: .

[0022] To make the technical solution of this invention clearer, the technical terms involved in this invention are explained as follows: Gelatinization: The process by which starch granules absorb water, swell, and rupture under heating conditions to form a paste-like solution.

[0023] Stirring current: The current consumed by the motor driving the stirring paddle during operation, measured in amperes (A). This current value changes with the stirring resistance (i.e., the viscosity of the mash), and can indirectly reflect the viscosity of the mash.

[0024] Viscosity: The frictional resistance generated within the gelatinized mash during flow, characterizing the viscosity of the material, and can also be expressed as viscosity. In this invention, the viscosity refers to the real-time viscosity of the gelatinized mash, denoted as μ.

[0025] Steam pressure: The absolute pressure of saturated steam used for heating, denoted by P, and the unit is kilopascal (kPa).

[0026] Steam flow rate: The mass of steam passing through a steam pipe per unit time, denoted as Q, with units of kilograms per hour (kg / hr).

[0027] Back pressure: The pressure at the steam outlet or downstream side, denoted as P. b The unit is kilopascal (kPa).

[0028] Saturated steam density: The mass of steam per unit volume in a saturated steam state, which is a function of steam pressure and is denoted as ρ(P).

[0029] Low-pass filtering: a signal processing method that allows low-frequency signals to pass through while attenuating or filtering out high-frequency noise signals. In this invention, it is used to filter out high-frequency noise such as environmental electromagnetic interference in the signals acquired by the current sensor, resulting in a smooth output current value.

[0030] PID controller: A feedback controller commonly used in industrial process control. In this invention, it is used to calculate the adjustment amount of steam flow rate based on current deviation.

[0031] Motor speed setting: The percentage of the stirring motor speed relative to the rated speed, used to characterize the stirring speed.

[0032] Viscosity peak: The local maximum value of the mash viscosity during the gelatinization process as temperature and time change.

[0033] Maximum steam pressure: The highest permissible steam pressure under the current mash viscosity conditions to prevent localized overheating or coking, denoted as P. max This value decreases as real-time viscosity increases and increases as real-time viscosity decreases.

[0034] Target steam flow rate: The steam flow rate setpoint calculated based on the maximum steam pressure using the pressure-flow function relationship, denoted as Q. s .

[0035] The above explanations of terms are for illustrative purposes only and do not constitute a limitation on the scope of protection of this invention.

[0036] Compared with existing technologies, it has the following beneficial effects: 1. Preventing localized overheating and coking, thus ensuring mash quality. This invention monitors the mash viscosity in real time using the stirring current. When the viscosity is high, the maximum allowable steam pressure is reduced, effectively preventing localized overheating and coking caused by excessive steam flow. Experiments have verified that no coking occurs during the gelatinization process after using this method.

[0037] 2. Reduce steam consumption and increase heating rate. This invention dynamically controls steam flow, increasing the maximum allowable steam pressure to accelerate heating when viscosity is low, and actively limiting pressure when viscosity is high, achieving precise steam delivery with minimal usage. Compared to traditional constant-pressure steam control, this significantly reduces steam consumption while increasing the gelatinization heating rate.

[0038] 3. Improved heat exchange efficiency and more uniform heating. When the stirring opening is 80%, the pressure fluctuation is minimal, the material is heated more evenly during gelatinization, and the heat exchange efficiency is significantly improved. In contrast, 70% stirring opening results in localized uneven gelatinization due to insufficient stirring intensity, while 90% stirring opening leads to increased energy consumption and excessive foam disturbance due to over-stirring.

[0039] 4. No additional viscometer required, utilizing existing equipment. This invention directly utilizes the existing stirring motor of the pasteurizing pot as a sensor, indirectly characterizing viscosity through current signals. This eliminates the need for expensive online viscometers, reducing equipment costs and maintenance expenses.

[0040] 5. Improve gelatinization efficiency and shorten production cycle. This invention dynamically adapts the heating rate to avoid prolonged production cycles and reduced equipment utilization caused by excessively slow heating. Using this method, gelatinization time can be shortened while ensuring complete gelatinization.

[0041] 6. Improved Beer Quality. This invention significantly reduces energy consumption and improves beer quality while ensuring gelatinization quality. By avoiding localized overheating, it effectively protects enzyme activity and guarantees the yield of fermentable sugars in subsequent saccharification processes. Attached Figure Description

[0042] Figure 1 This is a graph showing the relationship between steam pressure and steam flow rate under different stirring motor openings in Example 1 (rice). Figure 2 This is a graph showing the relationship between steam pressure and steam flow rate (starch-based) under different stirring motor opening settings in Example 1. Figure 3 This is a graph showing the relationship between steam pressure and steam flow rate when the stirring motor opening is 80% in Example 1 (rice). Figure 4 The graph shows the relationship between steam pressure and steam flow rate when the stirring motor opening is 80% in Example 1 (starch-based products). Figure 5 This is a temperature and viscosity curve (starch) during the gelatinization heating process when the stirring motor is at 80% opening in Example 1. Figure 6 This is a temperature and current curve of the gelatinization heating process (starch) when the stirring motor is turned on at 80% in Example 1. Figure 7This is a temperature-viscosity curve of the gelatinization heating process (rice) when the stirring motor is turned on at 80% in Example 1. Figure 8 This is a temperature and current curve (for rice) during the gelatinization heating process when the stirring motor is turned on at 80% in Example 1. Detailed Implementation

[0043] To make the technical means, inventive features, objectives and effects of the invention easier to understand, the invention is further described in conjunction with specific embodiments and accompanying drawings. However, the invention is not limited to the following embodiments.

[0044] Example 1 I. Dynamic Control System for Steam Flow in Gelatinization Process Based on Stirring Current The gelatinization pot used in this embodiment includes: a pot body, a steam jacket, a washing ball, a stirring paddle, a coil, and a temperature sensor. The stirring paddle has a diameter of 4.34 m and a rotation speed of 15 rpm.

[0045] The heating system includes steam pipes, a jacket, and an inner heating ring pipe, and heating is achieved through the steam jacket and the inner heating ring pipe.

[0046] Current sensor: Hall current sensor, accuracy ±0.5%, sampling frequency 1Hz, installed in the drive motor circuit, used to collect the current signal of the stirring motor in real time; Steam flow meter: Vortex flow meter, accuracy ±0.5%, sampling frequency 1Hz, installed on steam pipeline, used to detect steam flow; Pressure sensor: Installed in the steam system to detect steam pressure; Steam regulating valve: Installed on the steam pipeline, used to regulate the steam flow rate; Valve positioner: used to receive control signals and drive the steam regulating valve to operate; Control unit: electrically connected to the current sensor, steam flow meter, pressure sensor, steam regulating valve and valve positioner respectively.

[0047] II. Model Building (a) Establishing the pre-defined functional relationship between steam pressure and steam flow rate 1. Calibrate the optimal motor speed and opening. During the gelatinization and heating stage, multiple different motor speed opening percentages were set: 70%, 80%, and 90%. Steam flow and pressure data were simultaneously collected at each opening percentage, and the pressure fluctuation amplitude, flow response time, and unit steam heat consumption were analyzed for each opening percentage. The opening percentage with the smallest pressure fluctuation amplitude, shortest flow response time, and lowest unit steam heat consumption was selected as the optimal motor speed opening, which was then used as the fixed opening for subsequent control.

[0048] Experimental results show (see) Figure 1 , Figure 2 When the stirring opening is 80%, the pressure fluctuation is minimal, the material is heated more evenly during gelatinization, and the heat exchange efficiency is significantly improved. At 70%, insufficient stirring intensity leads to uneven gelatinization in some areas, while at 90%, excessive stirring causes increased energy consumption and excessive foam disturbance. Therefore, the optimal motor speed opening is 80% (see...). Figure 3 , Figure 4 ).

[0049] 2. Data collection and fitting function relationship Under the condition that the heat exchange efficiency of the gelatinization pot heat exchanger is stable and no scorching occurs, the stirring motor speed and opening degree are kept constant (i.e., 80%), and multiple sets of measured data of steam pressure and steam flow are collected synchronously at fixed intervals. Based on the collected measured data, the preset functional relationship model between steam pressure and steam flow is obtained.

[0050] This functional relationship is constructed based on the saturated steam mass flow rate formula: , Among them, Q s Steam mass flow rate, kg / hr; C d A: Flow coefficient, determined experimentally; A: Effective cross-sectional area of ​​the flow channel, m² 2 P: Absolute steam pressure, kPa; P b : Back pressure (outlet or downstream pressure), kPa; ρ(P): Saturated vapor density, a function of P.

[0051] When the absolute steam pressure P is in the range of 1 bar to 15 bar, the saturated steam density function ρ(P) is approximately expressed as: , During the experiment, ensure stable heat exchange efficiency and back pressure P. b Maintain a stable, low value much smaller than P. Obtain different P values ​​and their corresponding Q values ​​through experiments. s Value, from which C is derived d A. Theoretical synthesis constant. C has been experimentally calibrated. d A = 15650. Because P... b The value is much smaller than P, resulting in a simplified functional relationship between steam pressure and steam flow rate: , This model, representing a preset functional relationship between steam pressure and steam flow rate, is stored in the control unit.

[0052] (II) Establishment of the pre-defined functional relationship between current and viscosity The effect of fluid viscosity on stirring resistance is utilized: the higher the viscosity, the greater the resistance, requiring the motor to output more torque, which leads to an increase in operating current. Therefore, the current signal can indirectly reflect the viscosity.

[0053] Since the shape and size of the stirring paddle, the stirring speed, the mash level, the mash density, and the motor drive system are all fixed, a preset functional relationship between current and viscosity is derived: , Where I is the real-time current value of the stirring motor (A); I0 is the current value (A) when the viscosity of the gelatinized mash approaches zero; K is the equipment constant, determined experimentally; μ is the real-time viscosity of the gelatinized mash; and n is the exponent.

[0054] In the initial laminar flow state of gelatinization, the exponent n=1. I0 and K were obtained through experiments.

[0055] Experimental results show (see) Figures 5-8 When the current opening of the stirring motor is fixed at 80%, the stirring current and the viscosity of the material show a clear positive correlation.

[0056] (III) Establishment of the mapping relationship between viscosity and maximum vapor pressure For each viscosity value, the steam pressure is gradually adjusted using a step-by-step pressurization method, and the measured steam pressure P is read online at each pressure point. 测 Compared with the measured steam flow rate Q 测 Based on the aforementioned functional relationship between steam pressure and steam flow rate, the measured comprehensive constant C can be deduced. d A 测 C d A 测 With C d A comparison was made using the theoretical constant 15650. When the ratio of the two values ​​was below 90%, the heat transfer efficiency was determined to be significantly reduced, and the gelatinized mash was approaching its heat transfer limit. The corresponding steam pressure at this point is the maximum steam pressure P at that viscosity. max (After multiple experiments, it was found that when the ratio of the measured comprehensive constant to the theoretical comprehensive constant is less than 90%, the heat transfer resistance of the gelatinized mash increases sharply. Continuing to increase the steam pressure will no longer effectively increase the heating rate, but will instead increase the risk of local overheating and coking.) Example calibration data is shown in the table below: As shown in the table above, when the steam pressure rises to 2.0 bar, the ratio is 90.2%, which is the critical point for heat exchange efficiency. When the pressure rises to 2.1 bar, the ratio drops to 88.2%, and the heat exchange efficiency decreases significantly. Therefore, the maximum steam pressure P at this viscosity is... max It is 2.0 bar.

[0057] By performing the above calibration steps for different viscosities, a mapping relationship between viscosity and maximum vapor pressure can be established and stored in the control unit. During online control, the corresponding P is calculated by looking up a table or interpolating based on the real-time viscosity. max .

[0058] III. Dynamic Control of Steam Flow Rate in Gelatinization Process Based on Stirring Current This invention dynamically controls the steam flow rate by adjusting the stirring current, thereby regulating the steam supply parameters in real time and maximizing heat exchange efficiency while maintaining process stability. (According to the temperature-time curves, the sudden changes in current during gelatinization mainly occur at the beginning of gelatinization and liquefaction, while the current remains relatively stable in other stages. Therefore, the maximum steam pressure P...) max The most significant changes occur during the paste-forming and liquefaction stages, while other stages remain relatively stable. In actual control, the steam pressure setpoint is lower than the maximum steam pressure P. max That's it. Generally, the current trend is determined in 30-second cycles, and the maximum steam pressure P is updated accordingly. max and target steam flow rate Q s ).

[0059] Specifically, the following steps are included: Step 1: Obtain the real-time current value of the stirring motor. A current sensor (Hall current sensor, sampling frequency 1Hz) is used to acquire the current signal of the stirring motor, and the current signal is low-pass filtered to remove high-frequency noise and output a smooth real-time current value.

[0060] Step 2: Determine the real-time viscosity of the gelatinized mash. Based on the real-time current value and the preset functional relationship between current and viscosity, I=I0+K μ n (n=1 in the initial laminar flow state of gelatinization), determine the real-time viscosity μ of the gelatinized mash.

[0061] Step 3: Determine the maximum allowable vapor pressure at the current viscosity. Based on the real-time viscosity, determine the maximum permissible vapor pressure P at the current viscosity. max Specifically, this includes: At the current viscosity, the steam pressure is adjusted in a stepwise manner, and the measured steam pressure and measured steam flow rate are read online at each pressure point; Based on the functional relationship between steam pressure and steam flow rate, the measured comprehensive constant C can be deduced. d A 测 ; The measured comprehensive constant C d A 测 The measured comprehensive constant is compared with the theoretical comprehensive constant. When the ratio of the measured comprehensive constant to the theoretical comprehensive constant is lower than 90% of the preset threshold, the heat exchange efficiency is determined to be significantly reduced, and the current pressure point is taken as the maximum steam pressure at this viscosity. Perform the above calibration steps for different viscosities to establish the mapping relationship between viscosity and maximum vapor pressure.

[0062] Step 4: Calculate the target steam flow rate According to the maximum steam pressure P max And based on the preset functional relationship between steam pressure and steam flow rate, the target steam flow rate Q is calculated. s .

[0063] Step 5: Adjust the steam supply According to the target steam flow rate Q s The steam supply is dynamically controlled by adjusting the opening of the steam regulating valve. Specifically, the steam flow meter is equipped with temperature and pressure sensors, and displays the measured steam flow value Q after temperature and pressure compensation. 测 ; The control unit will control the target steam flow rate Q. s As a set value, the steam flow rate measurement value Q 测 As a feedback value, it is input to the PID controller. The PID controller outputs a 4-20mA control signal to the valve positioner of the steam regulating valve based on the deviation between the set value and the feedback value. After receiving the control signal, the valve positioner interprets the current signal and drives the pneumatic diaphragm or piston to generate corresponding thrust, causing the valve stem to move up and down, displacing the valve core, thereby changing the steam flow area, changing the steam flow rate, and ultimately affecting the measured steam flow rate Q. 测 Approaching the target steam flow rate Q s .

[0064] Step 6: Current Trend Monitoring (Anomaly Handling) The control unit compares the real-time current value with a preset normal current threshold range (based on historical stable operating data). If a continuous upward trend in current is detected within three consecutive sampling periods, or if the current increase exceeds 10%, it is determined to be an abnormal current trend. When an abnormal current trend is determined, the steam flow adjustment amount is calculated based on the current deviation using a PID controller, a target flow increment is generated, and the opening of the steam regulating valve is updated accordingly.

[0065] Step 7: Coordinated Pressure Monitoring The system collects the actual pressure of the steam system in real time; calculates the theoretical pressure corresponding to the current steam flow rate based on the functional relationship between the steam pressure and the steam flow rate; compares the actual pressure with the theoretical pressure, and if the relative deviation between the actual pressure and the theoretical pressure exceeds 5%, a warning signal is triggered, and the further increase in steam flow rate is limited.

[0066] Step 8: Staged control of multiple viscosity peaks When two or more viscosity peaks occur during the gelatinization process (e.g., two peaks appearing during the gelatinization process of rice or starch), steps 3 to 5 above are executed independently for each viscosity peak stage to achieve multi-stage dynamic control.

[0067] Example 2 Taking a beer brewing gelatinization pot as an example, the method of this invention is used to gelatinize rice-based raw materials. In the initial stage, the starch granules do not significantly absorb water and swell, the material viscosity is low, and the current remains at a low level and rises slowly. After entering the gelatinization stage, the starch granules rapidly absorb water and swell, colliding and entangled with each other, the system viscosity rises sharply, and the current rises synchronously; in the later gelatinization stage, the starch granules over-expand and break down, the viscosity gradually decreases, and the current drops back.

[0068] During this process, the control unit adjusts the steam flow rate in real time according to steps 1 to 5, while steps 6 to 8 provide anomaly handling and safety coordination. Results show that no localized overheating or coking occurred, the gelatinization time was reasonable, steam consumption was significantly reduced, and the mash quality was good. Similarly, the same control logic is applicable and effective for corn starch-based raw materials.

[0069] Taking the gelatinization pot at the Harbin Bingchang brand factory as an example, the feed amounts are: 9130 kg starch, 190 hl water, 800 kg malt, 40 hl water for malt feeding, and 3 kg Novozymes α-amylase added during the feeding process. Under the same starting temperature of 53℃ and ending temperature of 93℃, the traditional constant pressure steam control process has a heating time of 49 minutes and a steam consumption of 2234 kg; using the method of this invention, the heating time is 45 minutes and the steam consumption is 2058 kg. Calculations show that the method of this invention shortens the gelatinization heating time by 8.42% and reduces steam consumption by 7.87%.

[0070] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for dynamic control of beer gelatinization vapor flow rate based on stirring current, characterized in that, Includes the following steps: Obtain the real-time current value of the stirring motor; The real-time viscosity of the gelatinized mash is determined based on the real-time current value and the preset functional relationship between current and viscosity. Based on the real-time viscosity, determine the maximum allowable steam pressure at the current viscosity, wherein the maximum steam pressure decreases as the real-time viscosity increases and increases as the real-time viscosity decreases; calculate the target steam flow rate based on the maximum steam pressure and a preset functional relationship between steam pressure and steam flow rate; Adjust the opening of the steam regulating valve according to the target steam flow rate to dynamically control the steam supply.

2. The method according to claim 1, characterized in that, The process of obtaining the real-time current value of the stirring motor specifically includes: using a current sensor to collect the current signal of the stirring motor, and performing low-pass filtering on the current signal to filter out high-frequency noise and output a smooth real-time current value.

3. The method according to claim 1, characterized in that, The preset functional relationship between current and viscosity is as follows: ， Wherein, I is the real-time current value of the stirring motor, I0 is the current value when the viscosity of the gelatinized mash approaches zero, K is the equipment constant, μ is the real-time viscosity of the gelatinized mash, and n is the exponent.

4. The method according to claim 3, characterized in that, The exponent n=1.

5. The method according to claim 1, characterized in that, The process of establishing the functional relationship between steam pressure and steam flow rate in advance also includes a sub-step of calibrating the optimal motor speed opening: During the gelatinization heating stage, multiple different motor speed opening percentages were set, namely 70%, 80%, and 90%. Simultaneously collect steam flow and steam pressure data at each opening degree; Analyze the pressure fluctuation amplitude, flow response time, and unit steam heat consumption for each opening degree. The optimal motor speed opening is selected based on the smallest pressure fluctuation amplitude, the shortest flow response time, and the lowest unit steam heat consumption.

6. The method according to claim 5, characterized in that, The optimal motor speed opening is 80%.

7. The method according to claim 5, characterized in that, At the optimal motor speed setting, the speed setting is kept constant, and multiple sets of measured data on steam pressure and steam flow are collected synchronously at a fixed period. A functional relationship model between steam pressure and steam flow rate was obtained by fitting the collected measured data.

8. The method according to claim 1, characterized in that, The preset functional relationship between steam pressure and steam flow rate is as follows: ， Among them, Q s C represents the steam mass flow rate. d Where A is the flow coefficient, A is the effective cross-sectional area of ​​the flow channel, and P is the absolute pressure of the steam. b Let P be the back pressure, and ρ(P) be the saturated vapor density function.

9. The method according to claim 8, characterized in that, The saturated steam density function ρ(P) is approximately expressed as follows when the absolute steam pressure P is in the range of 1 bar to 15 bar: , The C d A was experimentally calibrated to 15650, which serves as a theoretical synthesis constant, and the back pressure P... b The pressure is much smaller than the absolute steam pressure P, thus yielding a simplified functional relationship between steam pressure and steam flow rate: 。 10. The method according to claim 1, characterized in that, The maximum steam pressure is pre-calibrated in the following manner: At the current viscosity, the steam pressure is adjusted in a stepwise manner, and the measured steam pressure and measured steam flow rate are read online at each pressure point; Based on the functional relationship between steam pressure and steam flow rate, the measured comprehensive constant C can be deduced. d A 测； The measured comprehensive constant C d A 测 The measured comprehensive constant is compared with the theoretical comprehensive constant. When the ratio of the measured comprehensive constant to the theoretical comprehensive constant is lower than a preset threshold, it is determined that the heat exchange efficiency has decreased significantly, and the current pressure point is taken as the maximum steam pressure at this viscosity. Perform the above calibration steps for different viscosities to establish the mapping relationship between viscosity and maximum vapor pressure.

11. The method according to claim 10, characterized in that, The preset threshold is 90%.

12. The method according to claim 1, characterized in that, It also includes a pressure co-monitoring step: Real-time acquisition of the actual pressure of the steam system; Based on the functional relationship between steam pressure and steam flow rate, calculate the theoretical pressure corresponding to the current steam flow rate; The actual pressure is compared with the theoretical pressure. If the relative deviation between the actual pressure and the theoretical pressure exceeds 5%, an early warning signal is triggered, and the further increase in steam flow is limited.

13. The method according to claim 1, characterized in that, When two or more viscosity peaks occur during the gelatinization process, the steps for determining the maximum steam pressure and calculating the target steam flow rate are executed independently for each viscosity peak stage to achieve multi-stage segmented dynamic control.

14. The method according to claim 1, characterized in that, The determination of the maximum steam pressure and the calculation of the target steam flow rate are repeated every 30 seconds.

15. The method according to claim 1, characterized in that, The adjustment of the steam regulating valve opening according to the target steam flow rate specifically includes: The target steam flow rate is used as the set value, and the steam flow rate measured by the steam flow meter is used as the feedback value and input into the PID controller. The PID controller outputs a control signal to the valve positioner of the steam regulating valve based on the deviation between the set value and the feedback value. The valve positioner drives the pneumatic diaphragm or piston to generate thrust according to the control signal, which drives the valve stem to move up and down, causing the valve core to be displaced, thereby adjusting the steam flow area and making the measured steam flow rate approach the target steam flow rate.

16. The method according to claim 1, characterized in that, It also includes a current trend monitoring step: The real-time current value is compared with a preset normal current threshold range; If the current shows a continuous upward trend within three consecutive sampling periods, or the current increase exceeds 10%, it is determined to be an abnormal current trend. When an abnormal current trend is detected, the steam flow adjustment amount is calculated based on the current deviation through the PID controller, the target flow increment is generated, and the opening of the steam regulating valve is updated accordingly. The normal current threshold range is preset based on historical stable operation data.

17. A dynamic control system for beer gelatinization steam flow rate based on stirring current, characterized in that, include: A gelatinization pot is used to hold raw materials and carry out a gelatinization reaction. The stirring system includes a stirring paddle and a drive motor disposed in the gelatinization pot; The heating system, including steam pipes, a jacket, and an inner heating ring, is used to provide heat to the gelatinization pot; A current sensor is installed in the circuit of the drive motor to collect the current signal of the stirring motor in real time. A steam flow meter is installed on a steam pipeline to detect the steam flow rate. A pressure sensor, installed within the steam system, is used to detect steam pressure; A steam regulating valve, installed on a steam pipeline, is used to regulate the steam flow rate according to the target steam flow rate; A valve positioner, connected to the steam regulating valve, is used to receive control signals and drive the steam regulating valve to operate; The control unit is electrically connected to the current sensor, steam flow meter, pressure sensor, steam regulating valve, and valve positioner, respectively. The control unit is configured to perform the method of any one of claims 1 to 16.

18. The system according to claim 17, characterized in that, The control unit is pre-configured with: A functional relationship model between current and viscosity is used to convert the collected real-time current value of the stirring motor into real-time viscosity. The functional relationship model is as follows: ， A functional relationship model between steam pressure and steam flow rate, wherein the functional relationship model is as follows: 。

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