A precise calculation method of true accumulated temperature suitable for process control of continuous grain dryer

Abstract

The present application discloses a method for accurately calculating the true accumulated temperature suitable for the control of the operation process of a continuous grain dryer, which relates to the technical field of grain drying process control and includes the following contents: obtaining a set of working performance parameters of the grain dryer, and selecting a drying process window during the continuous operation process, then forming a time matrix based on the data sampling period when the grain enters each drying section, and forming a temperature matrix based on the temperature at the corresponding moment; then interpolating the temperature matrix based on the interpolation method, and finally calculating the true accumulated temperature value of the grain during the drying process window based on the time matrix and the interpolated temperature matrix. The above-mentioned scheme of the present application estimates the temperature change of the grain during the drying process based on the interpolation method, which is closer to the actual value, and then uses the matrix analysis method to calculate the true accumulated temperature value of the continuous drying process. Using it as a control factor of the drying process can better reflect the changes in the characteristics and quality of the grain during the drying process, and the control effect is more ideal.

Description

Technical Field

[0001] The present application relates to the technical field of grain drying process control, and in particular to a method for accurately calculating true accumulated temperature suitable for the operation process control of a continuous grain dryer. Background Art

[0002] The basic goal of grain drying is to remove moisture from grain at the lowest cost and energy consumption while maintaining a stable drying process using simple and easy-to-use control methods, while also monitoring the moisture content of the grain and controlling the process quality.

[0003] Patent application number 201711469624.8 describes a method for measuring equivalent accumulated temperature during the continuous grain drying process. This method uses a temperature-measuring cable to measure the exhaust temperature at the dehumidification outlet, replacing the grain temperature sensor element to detect the grain temperature in each slow-down section of the grain dryer. The average of the measured values ​​is then used to calculate the equivalent accumulated temperature, which can easily lead to deviations from actual results. Patent application number 201910626904.8 describes a method for controlling the window of continuous grain drying based on equivalent accumulated temperature. This method uses a graphical method to control the drying process, using the moisture content of the grain exiting the drying machine as the primary control indicator and the equivalent accumulated temperature as the precise control indicator to adjust the machine. This results in higher control accuracy and stability, and a simpler, more intuitive, and easier-to-implement control process. However, the equivalent accumulated temperature does not reflect the actual accumulated temperature, limiting control effectiveness. Therefore, accurately calculating the actual accumulated temperature during the grain heating process not only better reflects changes in grain characteristics and quality during the drying process, but also improves drying control effectiveness when used as a control factor in the drying process. Summary of the Invention

[0004] The purpose of this application is to provide a precise calculation method for true accumulated temperature suitable for the operation process control of a continuous grain dryer, which can more accurately calculate the true accumulated temperature value during the continuous drying process and provide a basis for the continuous drying process control.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] The present application provides a method for accurately calculating true accumulated temperature suitable for process control of a continuous grain dryer, comprising the following steps:

[0007] A working performance parameter set of a grain dryer is obtained; the grain dryer includes a plurality of drying sections and slow-heating sections that are sequentially arranged and connected, and the grain to be dried passes through the plurality of drying sections and slow-heating sections in sequence.

[0008] During the working process of the grain dryer, any complete grain drying process is selected as the drying process window for calculating the true accumulated temperature value.

[0009] The data sampling periods of the grain entering each drying section during the drying process window form a time matrix.

[0010] The temperature of the grain at the time it enters each drying section during the drying process window constitutes a temperature matrix.

[0011] The temperature matrix is ​​interpolated based on the interpolation method to obtain an interpolated temperature matrix.

[0012] Based on the time matrix and the interpolated temperature matrix, the true accumulated temperature of the grain during the drying process window is calculated.

[0013] Optionally, obtaining a working performance parameter set of a grain dryer specifically includes the following steps:

[0014] According to the structural dimensions of the grain dryer in the drawings, the volume of each drying section and each slow-heating section of the grain dryer is estimated.

[0015] Set the initial data sampling period and initial grain discharge period according to actual conditions.

[0016] Obtain the volume of grain discharged by the grain discharge wheel per unit time when the grain dryer operates at the maximum grain discharge motor frequency.

[0017] According to the volume of grain discharged by the grain discharge wheel per unit time, the real-time grain discharge motor frequency and the real-time data sampling period, the volume of grain discharged by the grain discharge wheel within the real-time data sampling period is calculated.

[0018] Optionally, the volume of grain discharged by the grain discharge wheel during the real-time data sampling period is calculated according to the following formula:

[0019]

[0020] Among them, Q i is the volume of grain discharged by the grain wheel during the i-th data sampling period, K f is the correction factor, f t is the real-time grain discharge motor frequency, f m is the maximum grain discharge motor frequency, λ i is the i-th data sampling period, and V0 is the volume of grain discharged by the grain discharge wheel per unit time.

[0021] Optionally, the volume of grain discharged by the grain discharge wheel during the real-time data sampling period is calculated according to the following formula:

[0022]

[0023] Among them, Q i is the volume of grain discharged by the grain wheel during the i-th data sampling period, K f is the correction factor, f tis the real-time grain discharge motor frequency, f m is the maximum grain discharge motor frequency, λ i is the i-th data sampling period, V0 is the volume of grain discharged by the grain discharge wheel per unit time, τ i is the i-th grain distribution cycle, t w Free time for food preparation.

[0024] Alternatively, the grain discharge idle time can be expressed according to the following formula:

[0025]

[0026] Among them, AT0 is the initial theoretical accumulated temperature of grain, T j is the grain temperature in the jth drying section, V j is the volume of the jth drying section, and N is the number of drying sections.

[0027] Optionally, during the operation of the grain dryer, any complete grain drying process is selected as a drying process window for calculating the true accumulated temperature value, which specifically includes the following steps:

[0028] During the working process of the grain dryer, any moment when the grain passes through the grain dryer outlet is selected as the window end point.

[0029] The starting point of the window is determined based on the volume of each drying section and each slow recovery section of the grain dryer and the volume of grain discharged by the grain discharge wheel per unit time. The starting point of the window is the moment when the grain at the grain dryer outlet enters the grain dryer inlet.

[0030] According to the window starting point and window end point, the drying process window for calculating the true accumulated temperature value is determined.

[0031] Optionally, the time matrix is ​​as follows:

[0032]

[0033] Among them, λ k is the time matrix, t i The data sampling period at time, t i is the moment when the grain enters the i-th drying stage.

[0034] Optionally, the temperature matrix is ​​as follows:

[0035]

[0036] Among them, T k is the temperature matrix, is the Nth drying section at t i Grain temperature at time t iis the moment when the grain enters the i-th drying stage.

[0037] Optionally, the interpolated temperature matrix is ​​as follows:

[0038]

[0039] Among them, T′ k is the interpolation temperature matrix, Δ i,j The interpolation incremental data can be calculated using linear interpolation, drying equation interpolation or polynomial interpolation.

[0040] Alternatively, the true accumulated temperature of the grain during the drying process window can be calculated according to the following formula:

[0041]

[0042] Among them, AT is the true accumulated temperature of grain during the drying process window, T dk is the diagonal element matrix of the interpolated temperature matrix.

[0043] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0044] The present application provides a method for accurately calculating true accumulated temperature suitable for controlling the operation process of a continuous grain dryer. The method comprises the following steps: obtaining a set of working performance parameters of the grain dryer, selecting any complete grain drying process as a drying process window during the operation of the grain dryer, then forming a time matrix using the data sampling period of the grain entering each drying period during the drying process window, and forming a temperature matrix using the corresponding temperature at each drying period; then interpolating the temperature matrix based on an interpolation method to obtain an interpolated temperature matrix; and finally, calculating the true accumulated temperature of the grain during the drying process window based on the time matrix and the interpolated temperature matrix. When calculating the true accumulated temperature during the grain drying operation, the above-mentioned scheme of the present application estimates the temperature change of the grain during the drying process based on the interpolation method, which is closer to the actual value. Furthermore, a matrix analysis method is used to calculate the true accumulated temperature value of the continuous drying process, providing a basis for controlling the continuous drying process. Selecting true accumulated temperature as a control factor for the drying process can better reflect the changes in grain characteristics and quality during the drying process, and achieve a more ideal control effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0046] Figure 1 A flowchart of a method for accurately calculating true accumulated temperature suitable for controlling the operation process of a continuous grain dryer is provided in accordance with one embodiment of the present application.

[0047] Figure 2 This is a flowchart of step A1 of a method for accurately calculating true accumulated temperature suitable for controlling the operation process of a continuous grain dryer provided in one embodiment of the present application.

[0048] Figure 3 This is a flowchart of step A2 in a method for accurately calculating true accumulated temperature suitable for controlling the operation process of a continuous grain dryer provided in one embodiment of the present application.

[0049] Figure 4 A structural schematic diagram of a grain dryer provided in one embodiment of the present application, which is applicable to a method for accurately calculating true accumulated temperature for controlling the operation process of a continuous grain dryer.

[0050] Figure 5 A schematic diagram of the installation position of a temperature sensor in a grain dryer provided in an embodiment of the present application, which is applied to a method for accurately calculating true accumulated temperature for controlling the operation process of a continuous grain dryer. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0052] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0053] In an exemplary embodiment, Figure 1 As shown, a method for accurately calculating the true accumulated temperature suitable for the operation process control of a continuous grain dryer is provided, comprising the following steps:

[0054] A1. Obtain the working performance parameter set of the grain dryer. The grain dryer includes several drying sections and slow recovery sections that are arranged in sequence and connected to each other. The grain to be dried passes through several drying sections and slow recovery sections in sequence. The continuous grain drying process often uses a slow recovery section that is alternately set with one or more drying sections. During the slow recovery process, the grains can fully transfer heat and moisture inside and outside the grains to achieve a balance, which is beneficial to accelerate the precipitation rate, reduce thermal damage to the grains, and improve the quality after drying. In this embodiment, if Figure 2 In the flowchart shown, step A1 specifically includes the following steps:

[0055] A11. Based on the structural dimensions of the grain dryer drawing, estimate the volume of each drying section and each slow-heating section of the grain dryer.

[0056] A12. Set the initial data sampling period and initial grain discharge period according to actual conditions. The relationship between the initial data sampling period and the initial grain discharge period is as follows:

[0057] τ0=ω×λ0;

[0058] Among them, τ0 is the initial grain discharge period, λ0 is the initial data sampling period, and ω is a positive integer.

[0059] A13. Obtain the volume of grain discharged by the grain discharge wheel per unit time when the grain dryer operates at the maximum grain discharge motor frequency.

[0060] A14. Calculate the volume of grain discharged by the grain discharge wheel within the real-time data sampling period based on the volume of grain discharged by the grain discharge wheel within the unit time, the real-time grain discharge motor frequency, and the real-time data sampling period.

[0061] A2. During the working process of the grain dryer, select any complete grain drying process as the drying process window to be calculated for the true accumulated temperature value. In this embodiment, Figure 3 In the flowchart shown, step A2 specifically includes the following steps:

[0062] A21. During the operation of the grain dryer, any moment when the grain passes through the grain dryer outlet is selected as the window end point.

[0063] A22. Determine the window starting point based on the volume of each drying section and each slow drying section of the grain dryer and the volume of grain discharged by the grain discharge wheel per unit time. The window starting point is the moment when the grain at the grain dryer outlet enters the grain dryer inlet. k Then, the reverse method can be used to determine the starting time t1 of the grain entering the dryer, that is, the starting point of the window, and determine the t that meets the following conditions. k The first n moments, the corresponding moment is t k The starting time t1 when the grain enters the dryer:

[0064]

[0065] Accordingly, the time point at which grain enters each drying stage can be determined according to the following conditions:

[0066]

[0067] It can be understood that when calculating the time point when the grain enters each drying section using the above formula, the volume of the adjacent slow recovery section is included in the adjacent drying section. Although the temperature of the slow recovery section is not as high as that of the drying section, there is still moisture migration.

[0068] A23. Determine the drying process window for calculating the true accumulated temperature value based on the window starting point and window end point.

[0069] A3. The data sampling period of the grain entering each drying stage during the drying process window is used to form a time matrix. In this embodiment, the time matrix is ​​shown as follows:

[0070]

[0071] Among them, λ k is the time matrix, t i The data sampling period at time, t i is the moment when the grain enters the i-th drying stage.

[0072] A4. The temperature of the grain at each drying stage during the drying process window is used to form a temperature matrix. In this embodiment, the temperature matrix is ​​shown as follows:

[0073]

[0074] Among them, T k is the temperature matrix, is the Nth drying section at t i Grain temperature at time t i is the moment when the grain enters the i-th drying stage.

[0075] A5. Interpolate the temperature matrix based on the interpolation method to obtain an interpolated temperature matrix. In this embodiment, the interpolated temperature matrix is ​​shown as follows:

[0076]

[0077] Among them, T′ k is the interpolation temperature matrix, Δ i,j The interpolation incremental data can be calculated using linear interpolation, drying equation interpolation or polynomial interpolation.

[0078] The total number of drying sections from the i-1st drying section to the i-th drying section is (n i -n i-1 ) column data, then in the temperature matrix T k Insert (n i -n i-1 -1) rows, the temperature matrix T kbecomes the interpolation temperature matrix T′ k .

[0079] Use linear interpolation method:

[0080]

[0081] In another embodiment, the drying equation interpolation method is used:

[0082]

[0083] Among them, K is the coefficient, t is the time, M is the current outlet moisture, M0 is the initial moisture, M e It is the equilibrium moisture of grain under normal pressure.

[0084] In another embodiment, polynomial interpolation is used to process:

[0085]

[0086] Among them, a0, a1…a i is a constant, is the data sampling period at the corresponding moment.

[0087] A6. Based on the time matrix and the interpolated temperature matrix, the true accumulated temperature value of the grain during the drying process window is calculated. In this embodiment, the true accumulated temperature value of the grain during the drying process window is calculated according to the following formula:

[0088]

[0089] Among them, AT is the true accumulated temperature of grain during the drying process window, T dk is the diagonal element matrix of the interpolated temperature matrix.

[0090] In one embodiment, the volume of grain discharged by the grain discharge wheel during the real-time data sampling period can be calculated according to the following formula:

[0091]

[0092] Among them, Q i is the volume of grain discharged by the grain wheel during the i-th data sampling period, K f is the correction coefficient, which is generally 1. Small adjustments are made based on the moisture content of the grain and the actual situation. t is the real-time grain discharge motor frequency, f m is the maximum grain discharge motor frequency, λ i is the i-th data sampling period, and V0 is the volume of grain discharged by the grain discharge wheel per unit time.

[0093] In another embodiment, the volume of grain discharged by the grain discharge wheel during the real-time data sampling period can be calculated according to the following formula:

[0094]

[0095] Among them, Q i is the volume of grain discharged by the grain wheel during the i-th data sampling period, K f is the correction factor, f t is the real-time grain discharge motor frequency, f m is the maximum grain discharge motor frequency, λ i is the i-th data sampling period, V0 is the volume of grain discharged by the grain wheel per unit time, τ i is the i-th grain distribution cycle, t w The idle time for grain discharging is as follows:

[0096]

[0097] Among them, AT0 is the initial theoretical accumulated temperature of grain, T j is the grain temperature in the jth drying section, V j is the volume of the jth drying section, and N is the number of drying sections.

[0098] In a specific embodiment, the above embodiment provides a true accumulated temperature accurate calculation method suitable for continuous grain dryer operation process control, which is applied to Figure 4 In the grain dryer shown, the grain dryer includes a temperature cable 110, a moisture meter 111, a temperature transmitter 112, and a data processor 114; wherein, the temperature cable 110 includes a plurality of temperature sensing elements connected and transmitting data via a serial bus, and the temperature sensing elements distributed therein can directly sense the grain temperature inside the drying section; the temperature transmitter 112 is connected to the temperature cable 110, and is used to receive the temperature signal detected by the temperature sensing element in the temperature cable and convert it into a digital signal that can be received by the data processor; the data processor 114 is used to receive the temperature signal transmitted by the temperature transmitter 112 and calculate, display and store the true accumulated temperature; the continuous dryer and its ancillary equipment include a dryer body 211, a fan 212, a discharger 213, a temperature cable 110, a moisture meter 111, a temperature transmitter 112, a conversion interface 113 and a data processor 114. In addition, as Figure 5 As shown, a plurality of temperature sensors T0 to T5 are installed in each drying section of the dryer body.

[0099] When the grain dryer is performing the drying operation, the grain in the dryer body 211 falls slowly in the dryer due to its own gravity. During the falling process, the grain will pass through the grain storage section, drying section, slow cooling section, cooling section, and grain discharge section in sequence. In the drying section, it will be dried by the hot drying medium in the fan 212, and cooled in the cooling section. Finally, the discharger 213 will discharge the cooled grain out of the dryer body, and the whole drying process is completed.

[0100] The present application provides a precise calculation method for true accumulated temperature suitable for the control of the operation process of a continuous grain dryer. When calculating the true accumulated temperature in the grain drying operation, the temperature change of the grain during the drying process is estimated based on the interpolation method, which is closer to the actual value. The true accumulated temperature value of the continuous drying process is further calculated using a matrix analysis method, providing a basis for the continuous drying process control. Since the true accumulated temperature is a true reflection of the grain heating process, the use of the true accumulated temperature as the control factor of the drying process can better reflect the changes in grain characteristics and quality during the drying process, and the control effect is more ideal.

[0101] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0102] This document uses specific examples to illustrate the principles and implementation methods of this application. The description of the above examples is only intended to help understand the method and core concept of this application. At the same time, for those skilled in the art, based on the concept of this application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for accurately calculating true accumulated temperature suitable for the process control of a continuous grain dryer, characterized in that: include: Obtaining a set of working performance parameters of a grain dryer; the grain dryer includes a plurality of drying sections and slow drying sections that are sequentially arranged and connected, and the grain to be dried sequentially passes through the plurality of drying sections and slow drying sections; During the working process of the grain dryer, any complete grain drying process is selected as the drying process window for calculating the true accumulated temperature value; The data sampling periods of the grain entering each drying section during the drying process window form a time matrix; The temperature of the grain at each drying stage during the drying process window is used to form a temperature matrix; Performing interpolation processing on the temperature matrix based on an interpolation method to obtain an interpolated temperature matrix; Calculating the true accumulated temperature value of the grain during the drying process window based on the time matrix and the interpolated temperature matrix; The true accumulated temperature value is a true accumulated temperature value used to characterize the true reaction of the grain heating process.

2. A true accumulated temperature accurate calculation method suitable for continuous grain dryer operation process control according to claim 1, characterized in that: Get the working performance parameter set of the grain dryer, including: According to the structural dimensions of the grain dryer in the drawings, the volume of each drying section and each slow drying section of the grain dryer is estimated; Set the initial data sampling period and initial grain discharge period according to actual conditions; Obtaining the volume of grain discharged by the grain discharge wheel per unit time when the grain dryer operates at the maximum grain discharge motor frequency; The volume of grain discharged by the grain discharge wheel within the real-time data sampling period is calculated based on the volume of grain discharged by the grain discharge wheel within the real-time data sampling period.

3. A true accumulated temperature accurate calculation method suitable for continuous grain dryer operation process control according to claim 2, characterized in that: The volume of grain discharged by the grain discharge wheel during the real-time data sampling period is calculated using the following formula: Among them, Q i is the volume of grain discharged by the grain wheel during the i-th data sampling period, K f is the correction factor, f t is the real-time grain discharge motor frequency, f m is the maximum grain discharge motor frequency, λ i is the i-th data sampling period, and V0 is the volume of grain discharged by the grain discharge wheel per unit time.

4. A true accumulated temperature accurate calculation method suitable for continuous grain dryer operation process control according to claim 2, characterized in that: The volume of grain discharged by the grain discharge wheel during the real-time data sampling period is calculated according to the following formula: Among them, Q i is the volume of grain discharged by the grain wheel during the i-th data sampling period, K f is the correction factor, f t is the real-time grain discharge motor frequency, f m is the maximum grain discharge motor frequency, λ i is the i-th data sampling period, V0 is the volume of grain discharged by the grain discharge wheel per unit time, is the i-th grain distribution cycle, t w Free time for food preparation.

5. A true accumulated temperature accurate calculation method suitable for continuous grain dryer operation process control according to claim 4, characterized in that: The idle time for grain discharge can be expressed according to the following formula: Among them, AT0 is the initial theoretical accumulated temperature of grain, T j is the grain temperature in the jth drying section, V j is the volume of the jth drying section, and N is the number of drying sections.

6. A true accumulated temperature accurate calculation method suitable for continuous grain dryer operation process control according to claim 1, characterized in that: During the working process of the grain dryer, any complete grain drying process is selected as the drying process window for calculating the true accumulated temperature value, specifically including: During the operation of the grain dryer, any moment when the grain passes through the outlet of the grain dryer is selected as the window end point; The starting point of the window is determined according to the volume of each drying section and each slow drying section of the grain dryer and the volume of grain discharged by the grain discharge wheel per unit time; the starting point of the window is the moment when the grain at the grain dryer outlet enters the grain dryer inlet; A drying process window for calculating the true accumulated temperature value is determined according to the window starting point and the window end point.

7. The method for accurately calculating true accumulated temperature suitable for controlling the operation process of a continuous grain dryer according to claim 1, characterized in that: The time matrix is ​​shown below: Among them, λ k is the time matrix, t i The data sampling period at time, t i is the moment when the grain enters the i-th drying stage.

8. The method for accurately calculating true accumulated temperature suitable for controlling the operation process of a continuous grain dryer according to claim 1, characterized in that: The temperature matrix is ​​shown below: Among them, T k is the temperature matrix, is the Nth drying section at t i Grain temperature at time t i is the moment when the grain enters the i-th drying stage.

9. A true accumulated temperature accurate calculation method suitable for continuous grain dryer operation process control according to claim 8, characterized in that: The interpolated temperature matrix is ​​shown below: Among them, T′ k is the interpolation temperature matrix, Δ i,j The interpolation incremental data can be calculated using a linear interpolation method, a drying equation interpolation method, or a polynomial interpolation method.

10. A true accumulated temperature accurate calculation method suitable for continuous grain dryer operation process control according to claim 9, characterized in that: The true accumulated temperature of the grain during the drying process window is calculated according to the following formula: Wherein, AT is the true accumulated temperature of the grain during the drying process window, T dk is the diagonal element matrix of the interpolation temperature matrix.

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