A pusher type heating furnace temperature pre-control method and control system based on production rhythm

Abstract

The present invention relates to the field of metallurgical automatic control technology, and specifically to a method for pre-controlling the furnace temperature of a push-steel heating furnace based on production rhythm. It is intended to solve the problem that when there are many types of product specifications in domestic hot-rolled strip steel mills, the heat load of the heating furnace changes frequently, which leads to untimely temperature setting of the push-steel heating furnace, resulting in abnormal product heating quality, energy waste and other problems. The method comprises: obtaining the actual production rhythm Pu of different heating sections and calculating the predicted production rhythm Ppstc of different heating sections. For the preheating section on the furnace side: taking the predicted root number N to calculate the predicted production rhythm Ppstc of the heating section for the slab to be entered into the furnace; checking the process specification table according to the slab specification i, and determining the process control temperature of the preheating section of the slab specification i to be entered into the furnace; calculating the real-time temperature and sending it to the PLC.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgical automatic control, and in particular relates to a temperature pre-control method and a control system of a pusher type heating furnace based on production rhythm. Background Art

[0002] The heating furnace equipment itself is a large hysteresis system. Especially when the gas consumption rises and falls sharply due to the sudden change of production rhythm, the rise and fall of the furnace temperature in different heating sections is a relatively slow change process. Even if the gas consumption changes, it still takes time for the temperature in the furnace to reach the required temperature. The control system must be able to control the furnace temperature in advance near the temperature required by the production process within a period of time before the production rhythm changes. If the production rhythm cannot be accurately predicted in advance, it is very likely that the core temperature of the steel billet is not enough and the quality problem of failing to "burn through" the steel billet will occur. Affected by the heating furnace's heating capacity, when the process requires temperature changes, linearly connected temperatures are often used for transition between two temperature changes. Due to the influence of the large hysteresis characteristics of the heating furnace on the feedback control mechanism, the continuous increase of the gas flow in this section often leads to "overshoot". Although such adjustment will cause the temperature of the control section to rise quickly to the required temperature of the process system, due to the continuous increase in the temperature of the billet in the furnace, the temperature of the control section will soon exceed the control temperature, and PLC feedback adjustment is required to cool it down. This kind of furnace temperature fluctuation is likely to affect the precision of the furnace temperature measurement of the heating furnace, affect automatic control and even heating quality.

[0003] The invention patent with publication number CN110617716A, "A production rhythm and furnace temperature online control method for mixed steel heating", is a heating furnace temperature control method that uses a similar concept for control. The article focuses on optimizing the calculation of the space between steel billets in the case of mixed steel, which is only applicable to mixed steel walking heating furnaces, but does not describe pusher heating furnaces that produce strip products of different specifications.

[0004] The invention patents with publication number CN1840715A, "Hot rolling heating furnace temperature dynamic setting control method", and the invention patents with publication number CN103225017A, "A bar, wire, billet heating model control method and device", both involve the dynamic weighted setting of furnace temperature according to the current actual production rhythm. However, the technical solutions disclosed in the above two inventions do not involve the dynamic adjustment and control of the production rhythm, and cannot automatically identify the heating requirements of different products before production.

[0005] The patent "Model Control Method for Heating Furnace Temperature" with publication number CN 104049649A also fully considers the impact of changes in the production rhythm caused by the mixing of different products in the heating furnace, which causes changes in the heat load of the heating furnace. However, it does not consider the impact of the heating capacity of different heating furnaces under actual production conditions, that is, it does not consider how to change the heating furnace temperature in advance before the production rhythm is about to change, so as to adapt to the heating capacity in actual production conditions.

[0006] At present, domestic long strip heating furnaces have complete in-furnace tracking systems and heating process schedules for producing different products, which can determine changes in production rhythm. However, how to connect different production rhythms and predict this "time advance" is not mentioned in the above-mentioned public technical literature. Summary of the invention

[0007] The present invention aims to solve the problems that when there are many types of product specifications in domestic hot-rolled strip steel mills, the heat load of the heating furnace changes frequently, which leads to untimely temperature setting of the push-steel heating furnace, resulting in abnormal product heating quality and energy waste.

[0008] 1. In this regard, the present invention proposes a method for pre-controlling the temperature of a pusher-type heating furnace based on production rhythm, comprising the following control steps performed on each heating section of the pusher-type heating furnace:

[0009] S1 obtains the actual production rhythm P of the current heating section u Calculate the predicted production rhythm P of the heating section pstc The predicted production rhythm P of the heating section is calculated according to the following formula pstc ;

[0010]

[0011] In formula 1, P pstc is the predicted production rhythm of the heating section, N is the predicted number of slabs in the heating section, k is the slab counter, k is an integer, P uN-k+1 is the actual production rhythm under the number of roots N-k+1;

[0012] S2 queries the process specification table according to the slab specification i and determines the process control temperature of the slab specification i that is about to enter the heating section Calculate the real-time temperature according to the following formula and will Send to PLC:

[0013]

[0014] In formula 2, is the real-time temperature of the heating section, P pstc is the predicted production rhythm of the heating section described in S1, is the process control temperature of the slab specification i that is about to enter the heating section, P stc The production rhythm is counted for the heating section, and m is the number of the heating section.

[0015] Furthermore, each set of data in the process specification table is different heating section temperatures corresponding to different slab specifications or product specifications, and a standard production rhythm Pc corresponding to the slab specifications or product specifications.

[0016] Furthermore, the furnace tracking table includes data on slab identification, slab specifications, furnace time, absolute position, relative position, heating section, and standard production rhythm Pc in each heating section in the furnace.

[0017] Further, according to the heating capacity V of the current heating section t Determine the number of predicted elements N, V ​​described in S1 t The relationship with N is as follows:

[0018]

[0019] In formula 3, N is the number of predicted roots, v3, v2, v1, and v0 are the endpoint values ​​of several heating rate intervals divided according to the actual heating rate in the heating rate table; V t It is the heating capacity. Specifically, it refers to the speed at which the furnace temperature rises when the gas volume is increased under normal production conditions. The unit is ℃ / min.

[0020] Furthermore, the method further includes the step of creating the heating rate table, which specifically includes: calculating the measured heating rate of the current heating section under a stable heat load according to the following formula:

[0021]

[0022] In formula 4, is the measured heating rate of the slab specification i, δT is the heating amplitude, δT=T-T0; δτ is the measured heating time required to heat from the first steady-state temperature T0 to the second steady-state temperature T.

[0023] Furthermore, the method further includes a step of macroscopically tracking the slab in the pusher type heating furnace according to the furnace entry tracking table, and the step specifically includes:

[0024] When the host computer issues the steel loading operation instruction, the model server reads the specifications of the currently loaded slab and the specifications of the product to be processed from the production plan database;

[0025] When the pusher heating furnace completes the steel loading operation, the PLC sends the corresponding steel loading operation signal to the model server, which records the time the slab is in the furnace in real time and calculates the number of slabs in the furnace;

[0026] When the upper computer issues a steel operation instruction, the PLC sends the corresponding steel-out operation signal to the model server. The model server records the corresponding slab out-of-furnace time in real time, calculates the number of slabs in the furnace and stores the slab position information in real time.

[0027] Furthermore, it also includes calculating the statistical production rhythm P of each heating section stc Step, the calculation formula of this step is as shown in Formula 5:

[0028]

[0029] In formula 5, P stc To count the production rhythm, Pu n-k+1 is the actual production rhythm under the root number n-k+1, n is the selected root number, k is a counter, and the value of k is 1, 2,…, n.

[0030] Furthermore, the value range of the selected root number n is 2≤n≤5.

[0031] Furthermore, the actual production rhythm P u The calculation is performed by the following steps: reading the furnace-entry tracking table for the time when the n newly entered slabs are discharged from the furnace, and calculating the real-time production rhythm P r , with the standard production rhythm P c After comparison, the actual production rhythm P is obtained. u .

[0032] Correspondingly, the present invention also proposes a push-steel heating furnace temperature pre-control system based on production rhythm, the system includes at least one processor; and a memory storing instructions, which implement the steps of the above method when the instructions are executed by at least one processor.

[0033] The present invention adapts to the direct changes in specifications of different heating products by converting a time advance amount of a pre-control time according to the speed of the production rhythm of different products in the furnace and the heating capacity of the heating section at this temperature, so as to increase or decrease the furnace temperature in the control section in advance, reduce the temperature fluctuation caused by the lag of the system and avoid "overshoot", thereby effectively ensuring the heating quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 : Schematic diagram of the internal structure of some three-stage pusher type strip steel slab heating furnaces;

[0035] Figure 2 : Flowcharts of the main steps of some schemes;

[0036] Figure 3 : A working principle diagram of a method for pre-controlling the temperature of a push-steel heating furnace based on production rhythm;

[0037] Figure 4 : A module diagram of a temperature pre-control system of a pusher type heating furnace based on production rhythm; Figure 1 Explanation of the reference numerals: 1 preheating section, 2 heating section, 3 soaking section, a burner, b array of slabs. DETAILED DESCRIPTION

[0038] First, the following terms involved in the present invention should be interpreted as follows:

[0039] Production rhythm: an indicator indicating the production speed rate, which can be measured in seconds per root; in actual production, the production rhythm measurement method may be different according to different specifications of billets, such as size, steel type, furnace entry temperature, etc. This will lead to multiple ways to describe the production rate, such as tons / hour, root / hour, etc. A person skilled in the art can easily obtain an alternative solution for converting the units of the production rhythm according to the billet macroscopic tracking information without creative work according to the embodiments of the present invention.

[0040] Slab specifications (bill specifications): heated billet size, steel type;

[0041] Product specifications: width and thickness of finished strip steel;

[0042] Furnace time: Determine the appropriate heating time during the billet heating process;

[0043] Heating furnaces can be divided into open flame heating (the flame is in direct contact with the surface of the billet), thermal radiation tube heating (the flame burns in the thermal radiation tube and heats the billet through thermal radiation), etc. according to the heating method; according to the movement method of the billets in the furnace, they can be divided into push-type (there are no spaces between the billets, generally used for narrow strip production lines) and step-type (there can be spaces between the billets, generally used for wide strip and medium and thick plate production lines).

[0044] Walking beam heating furnaces are divided into two types: walking beam type and walking bottom type. Figure 1 A walking beam type heating furnace is shown. The loading and unloading methods are divided into: side-in and side-out, end-in and side-out, and end-in and end-out.

[0045] Since the thermal efficiency of continuous heating furnace is about 30% to 50%, and the production rhythm of products of different specifications on the production line is often different or even very different. For example, in a 550mm wide hot-rolled strip production line, the production time of each strip product of different widths and thicknesses ranges from 40s to 80s. The large difference in production rhythm of different specifications will lead to a significant change in gas consumption per unit time, so it is very important to be able to calculate the production rhythm in real time and accurately.

[0046] PLC is a programmable logic controller.

[0047] The following examples further illustrate the content of the present invention, but should not be construed as limiting the present invention. Without departing from the spirit and substance of the present invention, modifications or substitutions made to the methods, steps or conditions of the present invention all fall within the scope of the present invention.

[0048] The pusher type heating furnace according to the embodiment of the present invention has Figure 1 There are at least three heating sections shown, each of which is a control unit, and each control unit adopts a similar control method.

[0049] Some embodiments include performing, for each heating section of the pusher type heating furnace, Figure 2 The following control steps are shown:

[0050] S1 obtains the actual production rhythm P of different heating sections u Calculate the predicted production rhythm P of different heating sections pstc For this heating section, take the predicted number of slabs N and calculate the predicted production rhythm P of the heating section according to the following formula: pstc ;

[0051]

[0052] In formula 1, P pstc Predict the production rhythm for the heating section, N represents the number of predicted slabs, k is the slab counter, k is an integer, P uN-k+1 is the actual production rhythm under the root number N-k+1.

[0053] S2 queries the process specification table according to the slab specification i and determines the preheating process control temperature of the slab specification i that is about to enter the furnace Calculate the real-time temperature according to the following formula and will Send PLC to control real-time heating temperature:

[0054]

[0055] In formula 2, is the real-time temperature, P pstc Predict production rhythm for the heating section, is the process control temperature of the preheating section of the slab specification i that is about to enter the furnace, P stc Count the production rhythm for the heating section, and m is the number of the heating section.

[0056] It should be noted that the preheating process control temperature of the slab specification j that has entered the furnace is As the production rhythm in formula 2 changes, Will gradually approach to the same.

[0057] The predicted number N should be understood as the number of slabs that will enter the heating section. For example, for the first heating section (preheating section), N is the number of slabs that will enter the furnace. For the second heating section, N is the number of slabs that will be pushed out of the first heating section and enter the second heating section.

[0058] The purpose of S1 is to more accurately predict the production rhythm of products in real time, aiming to solve the control problem caused by the lag of the heating furnace system. S2 predicts the changes in the process temperature before different heating sections and the real-time production rhythm of the heating section, converts the rhythm changes into the control temperature changes, and performs nonlinear temperature rise control in advance.

[0059] Each set of data in the process schedule of some solutions is the different heating section temperatures corresponding to different slab specifications or product specifications, and the standard production rhythm Pc corresponding to the slab specifications or product specifications. It should be noted that the standard production rhythm Pc refers to the production time required for the rolling line under the current slab specifications or product specifications.

[0060] The furnace entry tracking table of some schemes includes the slab identification, slab specifications, furnace entry time, absolute position, relative position, heating section and production information of the standard production rhythm Pc of all heated slabs in the furnace. The absolute position can be obtained based on the product of the average slab moving speed Vs and the furnace time. The furnace time is the time difference between the furnace entry time recorded in the furnace entry tracking table and the actual time. The relative position is the data sorted according to the absolute position.

[0061] In the above scheme, according to the heating capacity V of different heating sections of the heating furnace t Determine the number of predicted elements N, V ​​described in S1 t The relationship with N is as follows:

[0062]

[0063] In formula 3, N is the number of predicted roots, v3, v2, v1, and v0 are the endpoint values ​​of several heating rate intervals divided according to the actual heating rate in the heating rate table; V t It is the heating capacity. Specifically, it refers to the speed at which the furnace temperature rises when the gas volume is increased under normal production conditions. The unit is ℃ / min.

[0064] Some solutions include the step of creating the heating rate table: calculating the measured heating rates of different heating sections under a stable heat load according to the following formula:

[0065]

[0066] In formula 4, is the measured heating rate of the slab specification i, δT is the heating amplitude, δT=T-T0; δτ is the measured heating time required to heat from the first steady-state temperature T0 to the second steady-state temperature T.

[0067] It should be noted that, since the temperature of the hot slab cannot be directly measured in production, the "measured heating rate" in the above scheme refers to the temperature of the heating section. "Stable heat load" refers to the heat load of the slab of the same specification in the current heating section under stable production. "Heating range" is the value of a calibrated heating range in different heating sections under production conditions.

[0068] On the basis of the above scheme, for the implementation method of the heating section close to the furnace discharge side, the measured heating rate of the slab specification i is obtained by dividing the corresponding required heating time δτ by every increase of 50°C or 100°C.

[0069] Some solutions also include the step of macroscopically tracking the slab in the pusher heating furnace according to the furnace entry tracking table:

[0070] When the operator clicks the steel loading operation on the heating furnace host computer, the model server reads the specifications of the currently loaded slab and the specifications of the product to be processed from the production plan database;

[0071] When the heating furnace completes the steel loading operation, the PLC sends the corresponding signal to the model server, which records the time the slab is in the furnace in real time and calculates the number of slabs in the furnace;

[0072] When the operator clicks the steel-out operation on the heating furnace host computer, the PLC sends the corresponding steel-out signal to the model server. The model server records and stores the corresponding slab out-of-furnace time in the database in real time, calculates the number of slabs in the furnace, realizes macroscopic tracking of the slabs, and stores the position information in real time in the database.

[0073] Some more specific solutions also include calculating the statistical production rhythm P of different heating sections stc step:

[0074] Read the furnace tracking table to record the time when the n slabs are newly put into the furnace and calculate the real-time production rhythm P r , with the standard production rhythm P c After comparison, the actual production rhythm P is obtained. u ; The calculation formula for this step is as shown in Formula 5:

[0075]

[0076] In formula 5, P stc To count the production rhythm, Pu n-k+1is the actual production rhythm under the root number n-k+1, n is the selected root number, k is the counter, and the value of k is 1, 2, ..., n. It should be noted that n is selected according to the stability of on-site production, and the value range of n is preferably 2≤n≤5 according to practical experience.

[0077] In one solution, the average slab moving speed Vs is calculated as follows:

[0078]

[0079] In the above formula, Pu is the actual production rhythm, W is the slab width, and Vs is the average moving speed of the slab.

[0080] In S1 of any of the above schemes, the actual production rhythm Pu is calculated by the following steps: reading the furnace-out time of n new slabs recorded in the furnace-entry tracking table, calculating the real-time production rhythm Pr, and comparing it with the standard production rhythm Pc to obtain the actual production rhythm Pu.

[0081] Here are some calculation methods for real-time production rhythm of some solutions:

[0082] The production rhythm of the hot strip production line has a significant impact on the combustion control of the heating furnace. Its production rhythm is expressed as the actual productivity. From the perspective of heat balance, the productivity of a heating furnace is P tons / hour, and the temperature of the steel entering the furnace is T in The furnace temperature setting value is T out , the specific heat capacity of carbon steel is C, then the heat Q that the billet needs to absorb per unit time when heated to the set value of the furnace is as follows:

[0083] Q=CP(T out -T in ) Formula 7

[0084] C in the above formula is the specific heat capacity of carbon steel, T in is the temperature of the steel when it enters the furnace, T out is the set value of the furnace temperature, Q is the heat that the billet needs to absorb per unit time when heated to the set value of the furnace, and P (tons / hour) is the productivity of the heating furnace.

[0085] In any of the above schemes, the units of production rhythm include seconds / root, tons / hour, and roots / hour. After converting the units of production rhythm, the heating section temperature can be controlled proportionally by predicting the production rate and the actual production rate as an alternative to the production rhythm.

[0086] An embodiment of the present invention relates to a method for pre-controlling the temperature of a pusher type heating furnace based on production rhythm, comprising: Figure 3 There are 6 steps shown, and each step is described in detail as follows.

[0087] Step 1: Establish a billet heating process schedule based on different billets and product specifications:

[0088] The heating process procedure table as shown in Table 1 established in this step includes different heating section temperatures corresponding to different specifications and standard production rhythms (the standard production rhythm here refers to the time required for the rolling line to produce products of this specification under the current specification, that is, the standard interval time for adjacent billets of the same specification to be discharged from the furnace, in seconds).

[0089] Table 1. Example of heating process schedule

[0090]

[0091] Step 2: Create a heating rate table

[0092] According to the actual heating speed (measured data) of different heating sections under the stable heat load on site, the corresponding heating speed table is created, as shown in Table 2.

[0093] Table 2. Heating speed table of different heating sections at different temperatures and hot and cold installation conditions

[0094]

[0095]

[0096] According to the table above, when the heat load is stable and the temperature is cold, it takes 115 seconds for the first heating stage to rise from a steady state of 500°C to a steady state of 700°C. The heating rate is as follows:

[0097]

[0098] When the heat load is stable and hot loading is performed, it takes 94 seconds for the first heating stage to rise from a steady state of 500°C to a steady state of 700°C. The heating rate is as follows:

[0099]

[0100] Step 3: Macroscopic tracking in the heating furnace

[0101] When the operator clicks the steel loading operation on the heating furnace host computer, the model server will read the specifications of the current loaded billet and the specifications of the product to be processed from the production plan database. When the heating furnace completes the steel loading operation, the PLC sends the corresponding signal to the model server, and the model server records the time the billet is in the furnace in real time and calculates the number of billets in the furnace. When the operator clicks the steel tapping operation on the heating furnace host computer, the PLC sends the corresponding steel tapping signal to the model server, and the model server records and stores the corresponding billet out of the furnace time in real time in the database, calculates the number of billets in the furnace, realizes macroscopic tracking of the billet, and stores the position information in real time in the database.

[0102] It should be noted that the macro-tracking of the billets in the furnace means that since there are no empty spaces between the billets in the push-steel thermal storage heating furnace, it is often not necessary to obtain the real-time position of each billet in the furnace during the actual production process. It is only necessary to track the positions of the head and tail billets in the furnace and the number and size information of the billets in the furnace. The position of each billet in the furnace can be obtained by calculation, thereby realizing the macro-tracking of the billets in the furnace.

[0103] Specifically, the production information of all heated billets recorded in the furnace tracking table as shown in Table 3 stored in the database is read through the model server, and the billet marked as Q1952308050126 is the first billet after the specification is changed.

[0104] Table 3. Example 1 of furnace tracking table

[0105]

[0106] It should be noted that if there are only two types of billets of specifications 2 and 3 in the current furnace, only heating section 1 has two types of billets of specifications 2 and 3, and the remaining heating sections are all billets of specification 3. In this embodiment, there are a total of 4 heating sections: heating section 1 is a preheating section, heating sections 2 and 3 are heating sections, and heating section 4 is a soaking section.

[0107] Step 4: Calculate the statistical production rhythm P of different heating sections stc

[0108] The control principle of step 4 is the same for each heating section of the multi-section heating furnace.

[0109] The preheating section at the furnace inlet side of this embodiment is taken as an example for detailed description.

[0110] Step 4 specifically includes: the model server reads the time when a number of new billets (5≥number of billets entering the furnace n≥2) are taken out of the furnace, calculates the real-time production rhythm Pr, and compares it with the standard production rhythm Pc to obtain the actual production rhythm Pu; then the actual production rhythm Pu under different numbers of billets is averaged to obtain the real-time statistical production rhythm P stc The following is an example of a furnace tracking table:

[0111] Table 4. Example 2 of furnace tracking table

[0112]

[0113] Due to the influence of mechanical errors, it can be considered that the standard production rhythm within ±1s is still considered standard production. According to the on-site production stability, the latest number of roots n is selected to calculate the average and obtain the statistical production rhythm Pstc.

[0114]

[0115] If n=2, the statistical production rhythm Pstc is 70s:

[0116]

[0117] If n=3, the statistical production rhythm Pstc is 69.33s:

[0118]

[0119] If n=4, the statistical production rhythm Pstc is 69.50s:

[0120]

[0121] If n=5, the statistical production rhythm Pstc is 67.60s:

[0122]

[0123] The purpose of this step is to more accurately reflect the real-time production rhythm of the product, because in actual production, due to various objective factors such as equipment status and rolling line production progress, the actual production rhythm often fluctuates within a certain range above and below the standard production rhythm. It can be seen that the larger n is, when the real-time production rhythm changes, the smaller the impact on the statistical production rhythm Pstc change, the more stable Pstc is, but the slower the response change speed is. The size of n needs to be determined based on the stability of the production rhythm of products with the same specifications. The more stable the production specifications, the smaller n is, but it should not be less than 2.

[0124] Step 5: Calculate the predicted production rhythm P of different heating sections pstc

[0125] This embodiment takes the preheating section at the furnace side as an example to illustrate step 5. Take the predicted number of roots N and perform the heating section prediction production rhythm P for the slabs about to enter the furnace. pstc Since the billet has not yet entered the furnace, the actual production rhythm can be considered to be equal to the standard production rhythm. The same calculation as step 4 predicts the production rhythm P pstc .

[0126]

[0127] If N = 2,

[0128]

[0129] If N=3,

[0130]

[0131] If N=4,

[0132]

[0133] If N=5,

[0134]

[0135] The purpose of this step is to more accurately predict the production rhythm of the product in real time, aiming to solve the control problem caused by the lag of the heating furnace system mentioned in the "Importance of accurate production rhythm prediction" above (the control feedback cycle is long, so pre-control is used). It can be seen that the larger N is, the more it can respond to changes in the production rhythm in advance, P pstc The earlier the change reaction, the more unstable it is. It is necessary to adjust the heating capacity V of different heating sections of the heating furnace. t Determine the size of N. Heating capacity V t The smaller it is, the larger N is. Generally, N should not be greater than 6.

[0136]

[0137] In the above formula, V3, V2, V1, and V0 are the endpoint values ​​of the interval divided according to the actual heating rate of the on-site heating furnace in step 2. For example, according to the heating rate table of different heating sections at different temperatures and hot and cold installation conditions in Table 2, V3 is 500°C, V2 is 700°C, V1 is 900°C, and V0 is 1000°C.

[0138] It should be noted that since the heating capacity of the pusher-type heating furnace is more limited than its cooling capacity, only the heating effect is considered.

[0139] Step 6: Increase the temperature in proportion to the predicted production rhythm changes:

[0140] This step mainly predicts the changes in the process temperature before different heating sections and the real-time production rhythm of the heating section, converts the rhythm changes into the control temperature changes, performs advance nonlinear temperature rise control, preheats reasonably, and ensures the heating quality.

[0141] Taking the furnace preheating section (heating section 1) as an example, the above steps are used to obtain the furnace preheating section Pstc and P pstc According to the specifications of the slabs that have not yet entered the furnace, check the process specification table to determine the process control temperatures of the specifications i that will be entered into the furnace and the specifications j that have already entered the furnace. Real-time temperature control is as follows:

[0142]

[0143] The real-time temperature can be sent to the PLC for control. As the production rhythm changes, the real-time control temperature will gradually approach the process control temperature of the preheating section.

[0144] Some of the proposals put forward are Figure 4The pusher-type heating furnace temperature pre-control system based on production rhythm shown includes at least one processor; and a memory storing instructions, which, when executed by at least one processor, implements the steps according to any of the above schemes.

[0145] The embodiments and functional operations of the subject matter described in this specification may be implemented in: digital electronic circuits, tangibly implemented computer software or firmware, computer hardware, including the structures disclosed in this specification and their structural equivalents, or a combination of more than one of the above. The embodiments of the subject matter described in this specification may be implemented as one or more computer programs, that is, one or more modules of computer program instructions encoded on one or more tangible non-transitory program carriers, for execution by a data processing device or to control the operation of the data processing device. Alternatively or in addition, the program instructions may be encoded on an artificially generated propagating signal, such as a machine-generated electrical, optical or electromagnetic signal, which is generated as encoded information for transmission to an appropriate receiver device executed by the data processing device. The computer storage medium may be a machine-readable storage device, a machine-readable storage substrate, a random or serial access memory device, or a combination of one or more of the above devices.

[0146] The term "data processing equipment" includes all kinds of equipment, devices and machines for processing data, including, as examples, programmable processors, computers or multiple processors or multiple computers. The equipment may include special-purpose logic circuits, such as FPGAs (field programmable gate arrays) or ASICs (application-specific integrated circuits). In addition to hardware, the equipment may also include code that creates an execution environment for related computer programs, such as code constituting processor firmware, protocol stacks, database management systems, operating systems, or a combination of one or more of them.

[0147] Specific implementations of the subject matter have been described. Other implementations are within the scope of the following claims. For example, the activities recited in the claims can be performed in a different order and still achieve the desired results. As an example, the processes described in the accompanying drawings do not necessarily require the specific order or sequential order shown in order to achieve the desired results. In certain implementations, multitasking and parallel processing may be advantageous.

Claims

1. A method for pre-controlling the temperature of a pusher type heating furnace based on production rhythm, characterized in that: The method comprises the following control steps performed on each heating section of the pusher type heating furnace: S1 obtains the actual production rhythm P of the current heating section u Calculate the predicted production rhythm P of the heating section pstc The predicted production rhythm P of the heating section is calculated according to the following formula pstc ; In formula 1, P pstc is the predicted production rhythm of the heating section, N is the predicted number of slabs in the heating section, k is the slab counter, k is an integer, P uN-k+1 is the actual production rhythm under the root number N-k+1; S2 queries the process specification table according to the slab specification i and determines the process control temperature of the slab specification i that is about to enter the heating section Calculate the real-time temperature according to the following formula and will Send to PLC: In formula 2, is the real-time temperature of the heating section, P pstc is the predicted production rhythm of the heating section described in S1, is the process control temperature of the slab specification i that is about to enter the heating section, P stc The production rhythm is counted for the heating section, and m is the number of the heating section.

2. The method according to claim 1, characterized in that Each set of data in the process specification table is different heating section temperatures corresponding to different slab specifications or product specifications, and the standard production rhythm Pc corresponding to the slab specifications or product specifications.

3. The method according to claim 1, characterized in that The furnace tracking table includes data on the slab identification, slab specifications, furnace time, absolute position, relative position, heating section, and standard production rhythm Pc in each heating section in the furnace.

4. The method according to claim 1, characterized in that: According to the heating capacity V of the current heating section t Determine the number of predicted elements N, V ​​described in S1 t The relationship with N is as follows: In formula 3, N is the number of predicted roots, v3, v2, v1, and v0 are the endpoint values ​​of several heating rate intervals divided according to the actual heating rate in the heating rate table; V t It is the heating capacity. Specifically, it refers to the speed at which the furnace temperature rises when the gas volume is increased under normal production conditions. The unit is ℃ / min.

5. The method according to claim 4, characterized in that The step of creating the temperature rise rate table is also included, and the step specifically includes: The measured heating rate of the current heating section under stable heat load is calculated as follows: In formula 4, is the measured heating rate of the slab specification i, δT is the heating amplitude, δT=T-T0; δτ is the measured heating time required to heat from the first steady-state temperature T0 to the second steady-state temperature T.

6. The method according to claim 5, characterized in that The step of macroscopically tracking the slab in the pusher type heating furnace according to the furnace entry tracking table is also included, and the step specifically includes: When the host computer issues the steel loading operation instruction, the model server reads the specifications of the currently loaded slab and the specifications of the product to be processed from the production plan database; When the pusher heating furnace completes the steel loading operation, the PLC sends the corresponding steel loading operation signal to the model server, which records the time the slab is in the furnace in real time and calculates the number of slabs in the furnace; When the upper computer issues a steel operation instruction, the PLC sends the corresponding steel-out operation signal to the model server. The model server records the corresponding slab out-of-furnace time in real time, calculates the number of slabs in the furnace and stores the slab position information in real time.

7. The method according to claim 6, characterized in that It also includes calculating the statistical production rhythm P of each heating section stc Step, the calculation formula of this step is as shown in Formula 5: In formula 5, P stc To count the production rhythm, Pu n-k+1 is the actual production rhythm under the root number n-k+1, n is the selected root number, k is a counter, and the value of k is 1, 2,…, n.

8. The method according to claim 7, characterized in that The value range of the selected root number n is 2≤n≤5.

9. The method according to claims 1-7, characterized in that: The actual production rhythm P u The calculation is performed by the following steps: reading the furnace-entry tracking table for the time when the n newly entered slabs are discharged from the furnace, and calculating the real-time production rhythm P r , with the standard production rhythm P c After comparison, the actual production rhythm P is obtained. u .

10. A pusher type heating furnace temperature pre-control system based on production rhythm, characterized in that: The system comprises at least one processor; and a memory storing instructions, which, when executed by the at least one processor, implement the steps of the method according to any one of claims 1 to 9.

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