Methanol hydrogen production temperature control method, system and device and storage medium

Abstract

The invention provides a methanol hydrogen production temperature control method, system and device, and a storage medium, and aims to solve the problem that PID and an improved algorithm thereof need to repeatedly iterate and set parameters on methanol electric heating devices with different design parameters. Wherein the temperature of a controlled object is collected periodically; fitting a temperature change curve of the controlled object; then, the predicted temperature and the predicted temperature change rate of the controlled object at the next moment are calculated based on the fitting result; and finally, regulating and controlling the output power of the heating device based on the predicted temperature and the predicted temperature change rate. Compared with a PID (Proportion Integration Differentiation) algorithm, the method disclosed by the invention can work only by acquiring a measured value of a controlled object, analyzing a change trend and setting an adjustment step value of each stage, is not easy to generate overshoot, and is safer for heating control of methanol.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen production technology, and specifically relates to a temperature control method, system, device and storage medium for producing hydrogen from methanol. Background Art

[0002] Methanol thermal decomposition to produce hydrogen (also known as methanol cracking to produce hydrogen) refers to a method of producing hydrogen by decomposing methanol into hydrogen and carbon monoxide through a catalytic reaction under high temperature conditions (about 240°C). Compared with other hydrogen production methods (such as natural gas reforming), the temperature of methanol thermal decomposition is relatively low, and the hydrogen yield is higher. At the same time, methanol, the raw material for hydrogen production, as a liquid, has the advantages of being easy to store and transport; and it can be decomposed on-site at the hydrogen use site to produce hydrogen, so as to further reduce the difficulty and cost of hydrogen transportation. Therefore, methanol thermal decomposition to produce hydrogen is particularly suitable for small hydrogen use scenarios.

[0003] In the process of heating methanol from liquid to gas and then to the target temperature, the proportional integral differential (PID) control algorithm and its improved form are usually used to adjust the power of heating devices such as electric heating rods to achieve temperature control during the heating process. The quality of the PID algorithm control effect depends on the setting of the PID parameters, which will be affected by different controlled objects and control parameters. When the parameters of the controlled object change, it is necessary to iterate and adjust the parameters. Therefore, in the methanol heating and decomposition hydrogen production equipment, the design parameters of the heating device generally need to be adjusted according to the usage scenarios of different users.

[0004] In practical applications, PID parameter tuning often uses the trial-and-error method. However, the trial-and-error method not only takes a long time to determine the parameters, but also can easily cause danger if the temperature overshoots too much during the test. For improved forms derived from traditional PID algorithms, such as fuzzy PID control, fuzzy PID control based on particle swarm optimization, and PID control based on crowd search algorithms, it is also necessary to perform iterative tuning based on the initial PID parameters to determine parameters such as the control domain and proportional factor in order to optimize the dynamic control performance of the algorithm for specific application scenarios. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a methanol hydrogen production temperature control method, system, device, and storage medium to solve the problem that PID and its improved algorithm need to repeatedly iterate and adjust parameters on methanol electric heating devices with different design parameters.

[0006] The present invention achieves the above technical objectives through the following technical means.

[0007] A method for controlling temperature of hydrogen production from methanol, characterized in that:

[0008] Step 1, periodically collect the temperature of the controlled object;

[0009] Step 2, fitting the temperature change curve of the controlled object;

[0010] Step 3: Calculate the expected temperature T′ of the controlled object at the next moment based on the fitting results i+1 and expected temperature change rate

[0011] Step 4: Based on the expected temperature T' i+1 and expected temperature change rate Regulates the output power of the heating device.

[0012] Furthermore, in step 4, the temperature control stages are divided according to the temperature range of the controlled object, and the output power of the heating device is regulated in each stage according to different temperature control strategies.

[0013] Furthermore, the following 6 temperature control stages are included:

[0014] T′ i+1 ≤S1·T tar When , it is the rapid heating stage, and the temperature control strategy is:

[0015]

[0016] S1·T tar <T′ i+1 ≤S2·T tar When , it is the deceleration heating stage, and the temperature control strategy is:

[0017]

[0018] S2·T tar <T′ i+1 ≤(1-p)T tar When it is the fine-tuning heating stage, the temperature control strategy is:

[0019]

[0020] (1-p)T tar <T′ i+1 ≤(1+p)T tar When , it is the steady-state control stage, and the temperature control strategy is:

[0021]

[0022] (1+p)T tar <T′ i+1 ≤(1+P)T tar When the temperature exceeds the limit slightly, the temperature control strategy is:

[0023]

[0024] T′ i+1 >(1 + P)T tar When it is in the stage of large temperature over - limit, the temperature control strategy is as follows:

[0025]

[0026] where u is the normalized value of the output power of the heating device, u i is the output power at the current moment, u i+1 is the output power at the next moment, is the temperature change rate at the current moment, S1 and S2 are two threshold nodes for temperature control, S1 < S2 < 1 - p, p is the accuracy requirement for temperature control at steady state, P is the maximum temperature over - limit amplitude, Δu L 、Δu M 、Δu S 、Δu N is the step size of each output power adjustment of the heating device, Δu L > Δu M > Δu S > Δu N , A1, B1, A2, B2, A3, B3, A4, B4, A5, B5 are temperature change rate thresholds, T tar is the target temperature value of the controlled object.

[0027] Furthermore, the output u0 of the heating device at the starting moment is:

[0028]

[0029] where T0 is the temperature of the controlled object at the starting moment, T max is the maximum temperature that the heating device can adjust.

[0030] Furthermore, S1 = 70%, S2 = 90%, P = 10%, Δu L = 0.2, Δu M = 0.02, Δu S = 0.002, Δu N = 0.0002, A3 = 0.5p℃ / Δt, B3 = - 0.5p℃ / Δt, Δt is the temperature sampling period;

[0031] The transformation relationship between the actual value and the normalized value of the output power of the heating device is:

[0032] f(u)=(b - a)·u + a

[0033] where the regulation range of the actual value of the output power of the heating device is [a, b].

[0034] Furthermore, in step 2, a quadratic curve is used for fitting, and the curve equation is:

[0035] T=a i ·t 2 +b i ·t+c i

[0036] Where t represents the time, T represents the temperature of the controlled object at the corresponding time, and a i , b i 、c i is the parameter of the quadratic curve at the i-th moment.

[0037] Further:

[0038] Step 2, by substituting time t i ,t i-1 ,t i-2 Temperature data under T i , T i-1 , T i-2 Perform curve fitting:

[0039]

[0040] For the starting time i=0, T -2 =T -1 =T0;

[0041] Step 3: Temperature change rate at the current moment

[0042] The expected temperature at the next moment

[0043] The expected temperature change rate at the next moment

[0044] A methanol hydrogen production temperature control system, comprising:

[0045] Controller: controlling the heating device according to the above-mentioned methanol hydrogen production temperature control method;

[0046] Sensor: The user periodically collects the temperature of the controlled object.

[0047] A methanol-to-hydrogen temperature control device, comprising a memory and a processor;

[0048] The memory is used to store computer programs;

[0049] The processor is used to execute the computer program and implement the above-mentioned methanol-to-hydrogen temperature control method when executing the computer program.

[0050] A methanol-to-hydrogen temperature control storage medium stores a computer program, which, when executed by a processor, causes the processor to execute the above-mentioned methanol-to-hydrogen temperature control method.

[0051] The beneficial effects of the present invention are:

[0052] (1) The present invention provides a methanol-to-hydrogen temperature control method, system, device, and storage medium. Compared with the PID algorithm, which requires modeling and analysis of the controlled object during parameter setting, the present method only needs to obtain the measured value of the controlled object, analyze the change trend, and set the adjustment step value at each level to work. It is not easy to overshoot, and is safer for the heating control of methanol.

[0053] (2) The present invention can be applied to the temperature control of various methanol electric heating devices without changing various parameters of the controller, thereby simplifying the steps of redetermining the temperature controller parameters during the design of various methanol electric heating devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is a flow chart of the temperature control method for producing hydrogen from methanol in an embodiment of the present application;

[0055] Figure 2 This is a schematic diagram of the division of the output power adjustment situations of the heating device in the embodiment of the present application;

[0056] Figure 3 It is a Simulink simulation block diagram in the embodiment of this application;

[0057] Figure 4 The comparison test results of the present invention and the existing PID control are shown in FIG.

[0058] Figure 5 For Figure 4 The comparative test results of the present invention and the existing PID control after changing the environmental parameters based on the situation. DETAILED DESCRIPTION

[0059] Embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0060] 1. Method and technical solution

[0061] Reference Figure 1 As shown, the temperature control method for producing hydrogen from methanol in this embodiment includes the following steps:

[0062] 1. Periodically collect the temperature of the controlled object

[0063] The temperature data of the controlled object is collected at fixed time intervals Δt.

[0064] 2. Fitting the temperature change curve

[0065] Based on the collected temperature data, a curve fitting of the temperature change over time is performed.

[0066] In this embodiment, a quadratic curve is specifically used to perform curve fitting on the current moment, where:

[0067] 1) The fitting curve equation is:

[0068] T=a i ·t 2 +b i ·t+c i

[0069] Where T represents the time, and T represents the temperature of the controlled object at the corresponding time.

[0070] 2) Use the temperature data of the current moment and the previous two moments for fitting:

[0071]

[0072] By inserting the time t i ,t i-1 ,t i-2 Temperature data under T i , T i-1 , T i-2 , we can get the parameter a of the quadratic curve at the i-th moment i , b i 、c i For the starting time when i=0, T can be artificially set -2 =T -1 =t0.

[0073] 3. Calculate the temperature change rate at the current moment And the expected temperature T' at the next moment i+1 and the expected temperature change rate

[0074] The curve obtained by fitting at the current time t = a i ·t 2 +b i ·t+c i ,calculate:

[0075] 1) Temperature change rate at the current moment

[0076]

[0077] 2) The expected temperature T' at the next moment i+1 :

[0078]

[0079] 3) Expected temperature change rate at the next moment

[0080]

[0081] This embodiment specifically uses a quadratic curve to fit the temperature change at each moment. Compared with the first-order curve fitting, the corresponding temperature change rate can be further calculated; compared with the third-order and above complex curves, the required calculation amount is lower. Therefore, this embodiment uses a quadratic curve to comprehensively balance the requirements of fitting accuracy and fitting speed.

[0082] 4. Adjust the heating control output at the next moment

[0083] Considering that actual power parameters of different heating devices are different, in this embodiment, the output power adjustment interval of the heating device is normalized to [0, 1].

[0084] 1) The output u0 of the heating device at the start time is:

[0085]

[0086] Where T tar is the target temperature value of the controlled object, T max The maximum value of the temperature that the heating device can adjust.

[0087] 2) In this embodiment, the temperature control process is divided into the following six stages, and the output power of the heating device is controlled according to different temperature control strategies in each stage:

[0088] S1,T′ i+1 ≤S1·T tar It is the rapid heating stage.

[0089] At this stage, as long as the output power of the heating device reaches the maximum value, the large step length Δu of each output power adjustment is L Increase output power:

[0090] u i+1 =u i +Δu L

[0091] S2, S1·T tar <T′ i+1 ≤S2·T tar It is the stage of deceleration and heating. Figure 2As shown, in this stage, the temperature change rate T′ at the next moment is predicted. i+1 Segmentation, where:

[0092] (1) hour

[0093] ① Then the large step length Δu of each output power adjustment is L Reduce output power: u i+1 =u i -Δu L ;

[0094] ② Then the medium step length Δu of each output power adjustment is M Reduce output power: u i+1 =u i -Δu M ;

[0095] ③ Then the medium step length Δu of each output power adjustment is M Increase output power: u i+1 =u i +Δu M ;

[0096] (2) hour

[0097] ① Then the large step length Δu of each output power adjustment is L Reduce output power: u i+1 =u i -Δu L ;

[0098] ② Then the medium step length Δu of each output power adjustment is M Reduce output power: u i+1 =u i -Δu M ;

[0099] ③ Then the medium step length Δu of each output power adjustment is M Increase output power: u i+1 =u i +Δu M ;

[0100] S3, S2·T tar <T′ i+1 ≤(1-p)T tar It is the stage of fine-tuning the temperature rise. Figure 2 As shown, in this stage, the temperature change rate T′ at the next moment is predicted.i+1 Segmentation, where:

[0101] (1) hour

[0102] ① Then the large step length Δu of each output power adjustment is L Reduce output power: u i+1 =u i -Δu M ;

[0103] ② Then the medium step length Δu of each output power adjustment is M Reduce output power: u i+1 =u i -Δu S ;

[0104] ③ Then the medium step length Δu of each output power adjustment is M Increase output power: u i+1 =u i +Δu S ;

[0105] (2) hour

[0106] ① Then the large step length Δu of each output power adjustment is L Reduce output power: u i+1 =u i -Δu M ;

[0107] ② Then the medium step length Δu of each output power adjustment is M Reduce output power: u i+1 =u i -Δu S ;

[0108] ③ Then the medium step length Δu of each output power adjustment is M Increase output power: u i+1 =u i +Δu S ;

[0109] S4, (1-p)T tar <T′ i+1 ≤(1+p)T tar At this stage, the temperature change rate T' at the next moment is predicted. i+1 To segment:

[0110] ① When the output power is adjusted, the steady-state step length Δu is N Reduce output power: u i+1 =u i -Δu N ;

[0111] ② When , the output power remains unchanged: u i+1 =u i ;

[0112] ③ When the output power is adjusted, the steady-state step length Δu is N Increase output power: u i+1 =u i +Δu N ;

[0113] S5, (1+p)T tar <T′ i+1 ≤(1+P)T tar When the temperature exceeds the limit slightly, Figure 2 As shown, in this stage, the temperature change rate T′ at the next moment is predicted. i+1 Segmentation, where:

[0114] (1) hour

[0115] ① Then the small step size Δu of each output power adjustment is S Reduce output power: u i+1 =u i -Δu S ;

[0116] ② Then keep the output power unchanged: u i+1 =u i ;

[0117] ③ Then the small step size Δu of each output power adjustment is S Increase output power: u i+1 =u i +Δu S ;

[0118] (2) hour

[0119] ① Then the output power is adjusted in small steps Δu each time. S Reduce output power: u i+1 =u i -Δu S ;

[0120] ② Then keep the output power unchanged: u i+1 =u i ;

[0121] ③ Then the output power is adjusted in small steps Δu each time. S Increase output power: u i+1 =u i +Δu S ;

[0122] (3) hour

[0123] ① Then the output power is adjusted in small steps Δi each time. S Reduce output power: u i+1 =u i -Δu S ;

[0124] ② Then keep the output power unchanged: u i+1 =u i ;

[0125] ③ Then the output power is adjusted in small steps Δu each time. S Increase output power: u i+1 =u i +Δu S ;

[0126] S6, T′ i+1 >(1+P)T tar When the temperature exceeds the limit, it is the stage where the temperature exceeds the limit. Figure 2 As shown, in this stage, the temperature change rate T′ at the next moment is predicted. i+1 Segmentation, where:

[0127] (1) hour

[0128] ① Then the medium step length Δu of each output power adjustment is M Reduce output power: u i+1 =u i -Δu M ;

[0129] ② Then keep the output power unchanged: u i+1 =u i ;

[0130] ③ Then the medium step length Δu of each output power adjustment isM Increase output power: u i+1 =u i +Δu M ;

[0131] (2) hour

[0132] ① Then the medium step length Δu of each output power adjustment is M Reduce output power: u i+1 =u i -Δu M ;

[0133] ② Then keep the output power unchanged: u i+1 =u i ;

[0134] ③ Then the medium step length Δu of each output power adjustment is M Increase output power: u i+1 =u i +Δu M ;

[0135] (3) hour

[0136] ① Then the medium step length Δu of each output power adjustment is M Reduce output power: u i+1 =u i -Δu M ;

[0137] ② Then keep the output power unchanged: u i+1 =u i ;

[0138] ③ Then the medium step length Δu of each output power adjustment is M Increase output power: u i+1 =u i +Δu M ;

[0139] In summary, at the next moment t i+1 The output of the heating device u i+1 for:

[0140]

[0141] Among them, S1 and S2 are two threshold nodes for temperature control, where S1 < S2 < 1 - p. In this embodiment, S1 = 70% and S2 = 90%; p is the accuracy requirement for temperature control at steady state, P is the maximum over - limit amplitude of temperature, and p < P. In this embodiment, P is set to 10%; Δu L is the large step size of the output power adjustment of the heating device each time. In this embodiment, the value is 0.2; Δu M is the medium step size of the output power adjustment of the heating device each time. In this embodiment, the value is 0.02; Δu S is the small step size of the output power adjustment of the heating device each time. In this embodiment, the value is 0.002; Δu N is the steady - state step size of the output power adjustment of the heating device each time. In this embodiment, the value is 0.0002; The temperature change rate thresholds A1, B1, A0, B2, A3, B3, A4, B4, A5, B5 are set manually. In this embodiment, A3 = 0.5p℃ / Δt and B3 = - 0.5p℃ / Δt.

[0142] Finally, according to the output u i+1 of the heating device at the next time point calculated for each time node, the output power of the heating device is adjusted. For a heating device with an actual output power adjustment range of [a, b], the actual output power of the heating device at the next time point is obtained according to the transformation function f(u)=(b - a)·u + a.

[0143] II. Testing

[0144] Use a computer to simulate the control process of heating methanol with heating devices of different parameters. The Simulink simulation block diagram is as Figure 3 shown.

[0145] Among them:

[0146] (1) When the transfer function of the furnace heating temperature is , according to the proportional, integral, and differential adjustment parameters obtained by the Ziegler - Nichols method, compared with the method described in the present invention, the results are as Figure 4 shown. The overshoot of the adjustment process is reduced from 10.19% to 1.33%, and the adjustment time is basically the same.

[0147] (2) In practical applications, if the furnace size, heating device, etc. change, that is, the transfer function G(s) of the furnace heating temperature changes. For example, when the transfer function in (1) changes to , if the control parameters of the PID controller remain unchanged and the method described in the present invention does not make parameter adjustments either, the adjustment curves of the two are as Figure 5As shown in the figure, since the PID controller does not perform parameter tuning for the new transfer function, the final steady-state error reaches 2.33%, while the final steady-state error of the method described in the present invention is 0.21%.

[0148] 3. Systems, Devices, and Storage Media

[0149] 1. Based on the same inventive concept as the above-mentioned methanol hydrogen production temperature control method, the present application also provides a methanol hydrogen production temperature control system, comprising:

[0150] Controller: Based on the acquired temperature data of the controlled object, the output power of the heating device at the next moment is obtained according to the temperature control method of methanol-to-hydrogen production of the present invention, and is used to control the heating device;

[0151] Sensor: The user periodically collects the temperature of the controlled object.

[0152] 2. The present application also provides an electronic device, which includes a processor and a memory, wherein the memory stores computer-readable code, wherein when the computer-readable code is executed by the processor, the methanol-to-hydrogen temperature control method of the present invention is implemented.

[0153] The memory includes a non-volatile storage medium and an internal memory; the non-volatile storage medium can store an operating system and a computer-readable code. The computer-readable code includes program instructions, which, when executed, can enable the processor to execute the methanol-to-hydrogen temperature control method. The processor is used to provide computing and control capabilities to support the operation of the entire electronic device. The memory provides an environment for the operation of the computer-readable code in the non-volatile storage medium, and when the computer-readable code is executed by the processor, the processor can execute the methanol-to-hydrogen temperature control method.

[0154] It should be understood that the processor may be a central processing unit, other general-purpose processors, digital signal processors, application-specific integrated circuits, field programmable gate arrays or other programmable logic devices, transistor logic devices, discrete hardware components, etc. Among them, the general-purpose processor may be a microprocessor or any conventional processor.

[0155] 3. The present application also provides a readable storage medium, which may be an internal storage unit of the electronic device described in the aforementioned embodiment, such as a hard disk or memory of the computer device. The readable storage medium may also be an external storage device of the electronic device, such as a plug-in hard disk, smart memory card, secure digital card, etc. equipped on the electronic device.

[0156] The present invention is not limited to the above-mentioned embodiments. Any obvious improvement, substitution or deformation that can be made by those skilled in the art without departing from the essential content of the present invention belongs to the protection scope of the present invention.

Claims

1. A method for controlling temperature of hydrogen production from methanol, characterized in that: Step 1, periodically collect the temperature of the controlled object; Step 2, fitting the temperature change curve of the controlled object; Step 3: Calculate the expected temperature T′ of the controlled object at the next moment based on the fitting results i+1 and expected temperature change rate Step 4: Based on the expected temperature T' i+1 and expected temperature change rate Regulates the output power of the heating device.

2. The methanol-to-hydrogen temperature control method according to claim 1, characterized in that: In step 4, the temperature control stages are divided according to the temperature range of the controlled object, and the output power of the heating device is regulated in each stage according to different temperature control strategies.

3. The methanol-to-hydrogen temperature control method according to claim 2, characterized in that: It includes the following 6 temperature control stages: T′ i+1 ≤S1·T tar When , it is the rapid heating stage, and the temperature control strategy is: S1·T tar <T′ i+1 ≤S2·T tar When , it is the deceleration heating stage, and the temperature control strategy is: S2·T tar <T′ i+1 ≤(1-p)T tar When it is the fine-tuning heating stage, the temperature control strategy is: (1-p)T tar <T′ i+1 ≤(1+p)T tar When , it is the steady-state control stage, and the temperature control strategy is: (1+p)T tar <T′ i+1 ≤(1+P)T tar When the temperature exceeds the limit slightly, the temperature control strategy is: T′ i+1 >(1+P)T tar When the temperature exceeds the limit, the temperature control strategy is: where u is the normalized value of the output power of the heating device, u i is the output power at the current moment, u i+1 is the output power at the next moment, is the temperature change rate at the current moment, S1 and S2 are two threshold nodes for temperature control, S1 < S2 < 1 - p, p is the accuracy requirement for temperature control at steady state, P is the maximum over - temperature amplitude, Δu L 、Δu M 、Δu S 、Δu N is the step size of each output power adjustment of the heating device, Δu L >Δu M >Δu S >Δu N , A1, B1, A2, B2, A3, B3, A4, B4, A5, B5 are temperature change rate thresholds, T tar is the target temperature value of the controlled object.

4. The methanol-to-hydrogen temperature control method according to claim 3, characterized in that: The output u0 of the heating device at the start time is: Where T0 is the temperature of the controlled object at the starting time, T max The maximum value of the temperature that the heating device can adjust.

5. The methanol-to-hydrogen temperature control method according to claim 3, characterized in that: S1=70%, S2=90%, P=10%, Δu L =0.2,Δu M =0.02, Δu S =0.002, Δu N =0.0002, A3=0.5p℃ / Δt, B3=-0.5p℃ / Δt, Δt is the temperature sampling period; The transformation relationship between the actual value and the normalized value of the heating device output power is: f(u)=(ba)·u+a The control range of the actual value of the heating device output power is [a, b].

6. The methanol-to-hydrogen temperature control method according to claim 1, characterized in that: In step 2, a quadratic curve is used for fitting, and the curve equation is: T=a i ·t 2 +b i ·t+c i Where t represents the time, T represents the temperature of the controlled object at the corresponding time, and a i 、b i 、c i is the parameter of the quadratic curve at the i-th moment.

7. The methanol-to-hydrogen temperature control method according to claim 6, characterized in that: Step 2, by substituting time t i ,t i-1 ,t i-2 Temperature data under T i , T i-1 , T i-2 Perform curve fitting: For the starting time i=0, T -2 =T -1 =T0; Step 3: Temperature change rate at the current moment The expected temperature at the next moment The expected temperature change rate at the next moment 8. A methanol hydrogen production temperature control system, characterized in that: include: Controller: controlling the heating device according to the methanol-to-hydrogen temperature control method according to any one of claims 1 to 7; Sensor: The user periodically collects the temperature of the controlled object.

9. A methanol-to-hydrogen temperature control device, characterized in that: including memory and processor; The memory is used to store computer programs; The processor is used to execute the computer program and implement the methanol-to-hydrogen temperature control method as described in any one of claims 1 to 7 when executing the computer program.

10. A methanol-to-hydrogen temperature control storage medium, characterized in that: A computer program is stored, and when the computer program is executed by a processor, the processor is caused to execute the methanol-to-hydrogen temperature control method according to any one of claims 1 to 7.

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