Three-furnace three-machine steel ladle matching optimization method

Abstract

The invention discloses a three-furnace three-machine steel ladle matching optimization method, belongs to the technical field of metallurgical engineering, and provides steel ladle matching scheduling and scheduling optimization. The method comprises the following steps that a production plan and steel ladle information are obtained, the method comprises the following steps: calculating the necessary heat transfer time of ladles, calculating the required theoretical number of ladles according to actual production, calculating the theoretical heat transfer time and the surplus time of the ladle transfer capacity by combining the number of ladles, and adjusting the theoretical number of ladles of the whole plant by analyzing the difference between the actual time and the planned time of converter, refining and continuous casting procedures and combining the dispatching time of a crown block. According to the steel ladle matching scheduling method, the steel ladle matching scheduling is formulated, so that the steel ladle matching optimization is realized.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgical engineering, and in particular to a method for optimizing the matching of a three-furnace three-machine ladle. Background Art

[0002] With the rapid development of industrial production technology, the steel manufacturing industry has increasingly higher requirements for the efficiency and quality of steelmaking workshops. Ladles are the most critical molten steel transportation container in the steelmaking process, and their turnover efficiency directly affects the overall production efficiency and molten steel quality of the steelmaking plant. In modern steelmaking production workshops, the management and scheduling of ladles must not only deal with complex process flows and diverse product types, but also ensure the close coordination of ladles with multiple links such as steelmaking, refining and continuous casting. In the steelmaking workshop with 3 converters, 3 LF furnaces and 3 continuous casting machines, ladles are the most critical molten steel operation container, and their turnover directly affects the production efficiency and molten steel quality of the steelmaking workshop.

[0003] However, the existing ladle management system still faces many problems and is difficult to meet the needs of efficient production: ladle management relies heavily on manual operation, ladle numbers and related information need to be manually entered, and ladles are manually allocated according to production plans and ladle status. This management method has the following problems: First, the high reliance on manual experience and skills leads to poor information acquisition and transmission, affecting the accuracy and timeliness of scheduling; second, manual operation is prone to delays or errors in the ladle allocation process, especially when dealing with complex production processes, information asymmetry or untimely communication may lead to incorrect use of ladles, affecting molten steel quality and production efficiency. In addition, when the production tasks in the workshop are complex, the product types are diverse, and the load fluctuations are large, the existing scheduling mode cannot cope with real-time changes, and it is easy to have unreasonable scheduling or delays, which in turn aggravates the fluctuations in production efficiency, resulting in rising costs and declining quality. In order to cope with the above problems, although there are some ladle scheduling and monitoring systems in the prior art, most of them lack the ability to intelligently monitor the real-time status of the ladle and dynamically schedule, and it is difficult to achieve efficient management of the ladle in a complex production environment. In particular, when dealing with multi-furnace and multi-machine parallel production, how to optimize the allocation and scheduling of ladles to achieve efficient supply of molten steel remains a pressing issue to be resolved. Summary of the invention

[0004] The object of the present invention is to provide a method for optimizing the selection of a three-furnace three-machine ladle to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for optimizing the selection of a three-furnace three-machine ladle, comprising the following steps:

[0006] S1: Obtaining production plan and ladle information, wherein the production plan includes the current daily output furnace number, steel type smelted in each furnace, crane transportation time, and scheduled time for steel tapping, refining and continuous casting processes; and the ladle information includes necessary heat turnover time data for the ladle, ladle age, ladle status, ladle material and furnace number;

[0007] S2: Count the necessary heat turnover time of the ladles, calculate the theoretical number of ladles required, calculate the theoretical heat turnover time based on the number of ladles, and then obtain the surplus time of the ladle turnover capacity. By analyzing the difference between the actual and planned time of each process of converter, refining and continuous casting, combined with the crane transportation time, adjust the theoretical number of ladles in the whole plant;

[0008] S3: To select the best ladle before tapping the converter, the most suitable ladle is selected according to the preset scheduling rules.

[0009] Furthermore, in step S1: the ladle status includes thermal turnover, offline baking and offline maintenance; the necessary thermal turnover time data of the ladle includes the actual operation time, slag pouring time, thermal repair time and transportation time of the necessary steel tapping, refining and continuous casting processes, without considering the waiting time of the ladle caused by equipment failure and operation conflict.

[0010] Further, in step S2: calculating the theoretical number of ladles and the surplus time of the ladle turnover capacity, the specific steps are as follows:

[0011] S2-1: Calculate the theoretical number of ladles required based on the current daily output furnace number. The calculation formula is as follows: N ladle_Th =N heat *T ladle_Th / 1440, where T ladle_Th Indicates the necessary thermal turnover time of the ladle, N heat Indicates the current daily production furnace number, N ladle_Th Indicates the theoretical number of ladles required;

[0012] S2-2: The theoretical number of ladles N required according to calculation ladle_Th Round up to get the rounded-up number of ladles N ladle ;

[0013] S2-3: According to the number of ladles N rounded up ladle Calculate the theoretical heat turnover time of the ladle, the calculation formula is as follows: T ladle =N ladle *1440 / N heat , where T ladle It indicates the theoretical thermal turnover time of the ladle;

[0014] S2-4: Calculate the surplus time of ladle turnover capacity. The calculation formula is as follows: Texcess =T ladle -T ladle_Th , where T excess Indicates the surplus time of ladle turnover capacity.

[0015] Furthermore, step S2 also includes: analyzing production fluctuations by counting actual time differences of each process, and judging whether the surplus time of ladle turnover capacity is sufficient to cope with these fluctuations. The specific steps are as follows:

[0016] S2-5: Count the difference between the actual start time and the planned start time, the actual end time and the planned end time of the converter, refining and continuous casting processes, the actual start time and the planned start time, the actual end time and the planned end time of the overhead crane, and count the distribution of the operation time difference;

[0017] S2-6: Compare the relationship between the inevitable surplus time and the difference in operating time. When the inevitable surplus time is greater than the difference in operating time, it means that the surplus time of the current ladle can meet the fluctuation of production and no additional ladle is needed; when the inevitable surplus time is less than the difference in operating time, it means that the surplus time of the current ladle cannot meet the fluctuation of production and additional ladle is needed; the calculation formula for the theoretical number of ladles in the whole plant after the addition is as follows: N incre_Th =N heat *(T ladle_Th +T dis ) / 1440,N incre_Th It represents the theoretical number of ladles in the whole plant after the addition, T dis Indicates the job time difference.

[0018] Furthermore, in step S3: the preset scheduling rules include: ladle selection process constraints and experience rules and ladle selection priorities.

[0019] Furthermore, in the ladle selection process constraints and empirical rules, there are material matching constraints for the steel grade of molten steel and ladle. The requirements for the ladle material of the molten steel carried by the converter for the molten steel out of the converter include the following situations, including selecting a high-aluminum ladle, selecting an aluminum-magnesium-carbon ladle, and selecting a magnesium-carbon ladle. Among them, when selecting a high-aluminum ladle, a low-quality aluminum-magnesium-carbon or magnesium-carbon ladle cannot be selected, and if magnesium-carbon can be selected, an aluminum-magnesium-carbon or high-aluminum ladle can also be selected; the constraints on the steel grade of the furnace for new ladle and cold ladle, the requirements for the selection of new ladle and cold ladle for specific molten steel are as follows: some steel grades are taboo to use new ladle; some steel grades are taboo to use cold ladle; some steel grades are both taboo to use It is taboo to use new ladle and cold ladle, and the steel types are classified according to the classification principle: the phosphorus content P in ordinary carbon steel is less than or equal to 0.02%, which is a low-phosphorus steel type, the alloy usage exceeds 1.5kg, which is a low-temperature steel type, the phosphorus content P in ordinary carbon steel is greater than 0.02% and less than 0.03%, which is a medium-phosphorus steel type, and the phosphorus content P in ordinary carbon steel is greater than or equal to 0.03%, which is a high-phosphorus steel type. All new ladle and cold ladle are not allocated to low-phosphorus steel and low-temperature steel, and are allocated to ordinary carbon steel first; the process path furnace plan requires that the ladle age is less than the rated maximum number of times; new ladle and cold ladle are not allocated to the first furnace of the continuous casting machine, the water change furnace, the shutdown furnace and the inverted ladle furnace.

[0020] Further, in step S3: the ladle allocation priority is divided into priority 1-3, among which priority 1 represents the selection of temperature, with reference to the temperature ladle selection priority, taking into account the above-mentioned constraints; priority 2 represents the selection of ladle age, with priority being given to ladle with a long ladle age, which is taken offline at each maintenance node and a new ladle is put online; priority 3 represents the selection of ladle number, with priority being given to ladle with a low ladle number, which has the lowest priority and is only selected as a new ladle for commissioning.

[0021] Further, in step S3: based on the ladle selection process constraints and empirical rules and ladle matching priority constraints, after forming the corresponding available ladle set for the furnace, the dispatcher selects the optimal ladle according to the following performance indicators, completes the molten steel transfer plan, and reversely infers the ladle temperature according to the natural cooling time interval. The natural cooling time interval of the ladle refers to the waiting time between two consecutive ladle transfer cycles. The site judges the temperature of the ladle based on this residence time and determines the priority of its next activation.

[0022] Furthermore, the temperature of the ladle is judged by the residence time on site, and the priority of the next activation is determined. The specific priorities are as follows: Priority 1: With the goal of not increasing the turnover of the ladle, priority is given to the disabling and commissioning of the ladle, that is, offline cold repairs must be carried out and newly baked ladles must be put into use. If the number of casting machines is increased, new ladles must be put into use; Priority 2: The time interval for the natural cooling of the ladle is less than half an hour. The ladle has just completed a transfer, and the temperature of the ladle is the most ideal steel-bearing condition; Priority 3: The time interval for the natural cooling of the ladle is greater than half an hour but less than 2 hours. This type of ladle only needs a short period of rapid baking before activation; Priority Level 4: The time interval for the natural cooling of the ladle is selected to be greater than 2 hours and less than 5 hours. At this time, if the ladle is used, it needs to be preheated and baked for a period of time; The preferred level 5: The time interval for the natural cooling of the ladle is greater than 5 hours. At this time, the ladle has been completely cooled to a lower temperature, which is equivalent to a cold ladle. By formulating ladle matching scheduling, production scheduling is used as a condition to meet the production scheduling and ladle matching constraints. A ladle matching optimization model is established with the goal of minimizing the energy consumption of ladle baking. Taking into account the limitations of molten steel material, steel type, time, temperature or other influencing factors, the ladle matching optimization scheduling and real-time ladle status update are realized.

[0023] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0024] 1. By designing ladle matching scheduling, under a given scheduling plan, ladles are allocated to supply molten steel: ensuring continuous casting and improving the constant drawing rate of the continuous casting machine; optimizing the transportation path of each ladle; minimizing the waiting time for each ladle; ensuring stable and efficient production operation, minimizing process energy consumption, and reducing the temperature drop of molten steel.

[0025] 2. Reduce dependence on manual operation, improve the fluency and accuracy of information transmission, thereby reducing the allocation error rate, ensuring the correct use of the ladle, and improving the quality of molten steel. At the same time, this method has dynamic scheduling capabilities, can respond to changes in production tasks and load fluctuations in real time, optimize ladle allocation, and reduce the risk of unreasonable scheduling or delays. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flow chart of a method for optimizing the selection of a three-furnace three-machine ladle according to the present invention. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] like Figure 1 As shown, the present invention provides a technical solution: a method for optimizing the selection of a three-furnace three-machine ladle, comprising the following steps:

[0029] S1: Obtaining production plan and ladle information, wherein the production plan includes the current daily output furnace number, steel type smelted in each furnace, crane transportation time, and scheduled time for steel tapping, refining and continuous casting processes; and the ladle information includes necessary heat turnover time data for the ladle, ladle age, ladle status, ladle material and furnace number;

[0030] S2: Count the necessary heat turnover time of the ladles, calculate the theoretical number of ladles required, calculate the theoretical heat turnover time based on the number of ladles, and then obtain the surplus time of the ladle turnover capacity. By analyzing the difference between the actual and planned time of each process of converter, refining and continuous casting, combined with the crane transportation time, adjust the theoretical number of ladles in the whole plant;

[0031] S3: To select the best ladle before tapping the converter, the most suitable ladle is selected according to the preset scheduling rules.

[0032] In step S1: the ladle status includes thermal turnover, offline baking and offline maintenance; the necessary thermal turnover time data of the ladle includes the actual operation time, slag pouring time, thermal repair time and transportation time of the necessary steel tapping, refining and continuous casting processes, without considering the waiting time of the ladle caused by equipment failure and operation conflict.

[0033] In step S2: calculating the theoretical number of ladles and the surplus time of the ladle turnover capacity, the specific steps are as follows:

[0034] S2-1: Calculate the theoretical number of ladles required based on the current daily output furnace number. The calculation formula is as follows: N ladle_Th =N heat *T ladle_Th / 1440, where T ladle_Th Indicates the necessary thermal turnover time of the ladle, N heat Indicates the current daily production furnace number, N ladle_Th Indicates the theoretical number of ladles required;

[0035] S2-2: The theoretical number of ladles N required according to calculation ladle_Th Round up to get the rounded-up number of ladles N ladle ;

[0036] S2-3: According to the number of ladles N rounded up ladle Calculate the theoretical heat turnover time of the ladle, the calculation formula is as follows: T ladle =N ladle *1440 / N heat , where Tladle It indicates the theoretical thermal turnover time of the ladle;

[0037] S2-4: Calculate the surplus time of ladle turnover capacity. The calculation formula is as follows: T excess =T ladle -T ladle_Th , where T excess Indicates the surplus time of ladle turnover capacity.

[0038] In step S2: by counting the actual time difference of each process, analyzing the production fluctuation, judging whether the surplus time of the ladle turnover capacity is sufficient to cope with these fluctuations, the specific steps are as follows:

[0039] S2-5: Count the difference between the actual start time and the planned start time, the actual end time and the planned end time of the converter, refining and continuous casting processes, the actual start time and the planned start time, the actual end time and the planned end time of the overhead crane, count the distribution of the operation time difference, and calculate the maximum value of the points within 98%;

[0040] S2-6: Compare the relationship between the inevitable surplus time and the difference in operating time. When the inevitable surplus time is greater than the difference in operating time, it means that the surplus time of the current ladle can meet the fluctuation of production and no additional ladle is needed; when the inevitable surplus time is less than the difference in operating time, it means that the surplus time of the current ladle cannot meet the fluctuation of production and additional ladle is needed; the calculation formula for the theoretical number of ladles in the whole plant after the addition is as follows: N incre_Th =N heat *(T ladle_Th +T dis ) / 1440,N incre_Th It represents the theoretical number of ladles in the whole plant after the addition, T dis Indicates the job time difference.

[0041] In step S3: the preset scheduling rules include: ladle selection process constraints and experience rules and ladle selection priorities.

[0042] Among the ladle selection process constraints and empirical rules, there are material matching constraints for the steel grade of molten steel and ladle. The requirements for the ladle material of the molten steel carried by the converter for steel tapping include the following situations, including selecting a high-aluminum ladle, selecting an aluminum-magnesium-carbon ladle, and selecting a magnesium-carbon ladle. Among them, when selecting a high-aluminum ladle, a low-quality aluminum-magnesium-carbon or magnesium-carbon ladle cannot be selected, and if magnesium-carbon can be selected, an aluminum-magnesium-carbon or high-aluminum ladle can also be selected; the constraints on the steel grade of the furnace for new ladle and cold ladle, the requirements for the selection of new ladle and cold ladle for specific molten steel are as follows: some steel grades are taboo to use new ladle; some steel grades are taboo to use cold ladle; some steel grades are both taboo to use It is taboo to use cold ladle for new ladle, and steel types are classified according to the classification principle: ordinary carbon steel with phosphorus content P less than or equal to 0.02% belongs to low-phosphorus steel, alloy usage exceeding 1.5kg belongs to low-temperature steel, ordinary carbon steel with phosphorus content P greater than 0.02% and less than 0.03% belongs to medium-phosphorus steel, and ordinary carbon steel with phosphorus content P greater than or equal to 0.03% belongs to high-phosphorus steel. All new ladle and cold ladle are not allocated to low-phosphorus steel and low-temperature steel, and are allocated to ordinary carbon steel first; the process path furnace plan requires that the ladle age is less than the rated maximum number of times; new ladle and cold ladle are not allocated to the first furnace of continuous casting machine, water change furnace, shutdown furnace and inverted ladle furnace.

[0043] In step S3: the ladle allocation priority is divided into priority 1-3, among which priority 1 represents the selection of temperature, referring to the temperature ladle selection priority, taking into account the above constraints; priority 2 represents the selection of ladle age, giving priority to ladle with high ladle age, which is taken offline at each maintenance node and new ladle is put online; priority 3 represents the selection of ladle number, giving priority to ladle with low ladle number, which has the lowest priority and is only used as an option for new ladle commissioning.

[0044] In step S3: based on the ladle selection process constraints and empirical rules and ladle matching priority constraints, after forming the corresponding available ladle set for the furnace, the dispatcher selects the optimal ladle according to the following performance indicators, completes the molten steel transfer plan, and reversely infers the ladle temperature according to the natural cooling time interval. The natural cooling time interval of the ladle refers to the waiting time between two consecutive ladle transfer cycles. The site judges the temperature of the ladle based on this residence time and determines the priority of the next activation.

[0045] The temperature of the ladle is judged by the residence time on site, and the priority of the next activation is determined. The specific priorities are as follows: Priority 1: With the goal of not increasing the turnover of the ladle, priority is given to the disabling and commissioning of the ladle, that is, offline cold repairs must be carried out and newly baked ladles must be put into operation. Increasing the number of casting machines requires the addition of new ladles; Priority 2: The time interval for the natural cooling of the ladle is less than half an hour. The ladle has just completed a transfer, and the temperature of the ladle is the most ideal steel-bearing condition; Priority 3: The time interval for the natural cooling of the ladle is greater than half an hour but less than 2 hours. This type of ladle only needs a short period of rapid baking before activation; Priority 4 : The time interval for natural cooling of the ladle is selected to be greater than 2 hours and less than 5 hours. At this time, if the ladle is used, it needs to be preheated and baked for a period of time; Optimization level 5: The time interval for natural cooling of the ladle is greater than 5 hours. At this time, the ladle has been completely cooled to a lower temperature, which is equivalent to a cold ladle. By formulating ladle matching scheduling, production scheduling is used as a condition to meet the production scheduling and ladle matching constraints. A ladle matching optimization model is established with the goal of minimizing the energy consumption of ladle baking. Taking into account the limitations of molten steel material, steel type, time, temperature or other influencing factors, the ladle matching optimization scheduling and real-time ladle status update are realized.

[0046] In the embodiment: the production turnover process data of three furnaces and three machines, the information of the current production plan and the status information of the ladle are obtained through sensors, and the production turnover process data obtained include the current daily output of 130 furnaces, the smelting steel type: ordinary carbon steel, the necessary heat turnover time of the ladle is 70 minutes, the on-site statistical operation time is 10 minutes, according to N ladle_Th =N heat *T ladle_Th / 1440=6.3, calculate the theoretical number of ladles required for the current daily output furnace number calculation; according to the calculated theoretical number of ladles required N ladle_Th Round up to get the rounded-up number of ladles N ladle =7; According to T ladle =N ladle *1440 / N heat =77.5, the theoretical heat turnover time of the ladle is calculated; according to T excess =T ladle -T ladle_Th =7.5, calculate the necessary surplus time for ladle turnover capacity; compare the necessary surplus time with the operation difference fluctuation and the operation time difference. The necessary surplus time 7.5 is less than the operation difference fluctuation and the operation time difference 10. At this time, the surplus time of the current ladle cannot meet the production fluctuation, and a new ladle is needed. According to N incre_Th =N heat *(T ladle_Th +T dis) / 1440=7.2, rounded to 8, get the theoretical number of ladles in the whole plant after the addition, get the specific status and position data of the ladles, there are 10 ladles in the current process, of which 8 are in hot turnover state and 2 are in offline baking state. The specific data are as follows: Ladle No. K1, position: continuous casting 1, status: hot turnover, offline time 43min; Ladle No. K2, position: continuous casting 2, status: hot turnover, offline time 25min; Ladle No. K3, position: continuous casting 3, status: hot turnover, offline time 42min; Ladle No. K4, position: refining 1, status: hot turnover, offline time 32min; Ladle No. K5, position: refining 1, status: hot turnover, offline time 19min; Ladle No. K6, position: refining 1, status: hot turnover, offline time 20min; Ladle No. K7, position: hot repair, status: hot turnover, offline time 22min; ladle number K9, position: baking, status: offline baking; ladle number K10, position: cold repair, status: offline baking; ladle number K10, position: hot repair, status: hot turnover, offline time 32min; there are 10 ladles on site, 8 of which are in hot turnover. Ladles are selected from the 8 ladles and selected according to the rules. The converter ladle is a non-hot turnover ladle. For the production process ladle, only K7 and K8 are left. Without specialization of steel types, the ladle with the shortest offline time is selected, that is, K7 ladle is selected.

[0047] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for optimizing the selection of a three-furnace three-machine ladle, comprising the following steps: S1: Obtaining production plan and ladle information, wherein the production plan includes the current daily output furnace number, steel type smelted in each furnace, crane transportation time, and scheduled time for steel tapping, refining and continuous casting processes; and the ladle information includes necessary heat turnover time data for the ladle, ladle age, ladle status, ladle material and furnace number; S2: Count the necessary heat turnover time of the ladles, calculate the theoretical number of ladles required, calculate the theoretical heat turnover time based on the number of ladles, and then obtain the surplus time of the ladle turnover capacity. By analyzing the difference between the actual and planned time of each process of converter, refining and continuous casting, combined with the crane transportation time, adjust the theoretical number of ladles in the whole plant; S3: To select the best ladle before tapping the converter, the most suitable ladle is selected according to the preset scheduling rules.

2. The method for optimizing the selection of three-furnace three-machine ladles according to claim 1, characterized in that: In step S1: the ladle status includes thermal turnover, offline baking and offline maintenance; the necessary thermal turnover time data of the ladle includes the actual operation time, slag pouring time, thermal repair time and transportation time of the necessary steel tapping, refining and continuous casting processes, without considering the waiting time of the ladle caused by equipment failure and operation conflict.

3. The method for optimizing the selection of three-furnace three-machine ladles according to claim 1, characterized in that: In step S2: calculating the theoretical number of ladles and the surplus time of the ladle turnover capacity, the specific steps are as follows: S2-1: Calculate the theoretical number of ladles required based on the current daily output furnace number. The calculation formula is as follows: N ladle_Th =N heat *T ladle_Th / 1440, where T ladle_Th represents the necessary thermal turnover time of the ladle, N heat Indicates the current daily production furnace number, N ladle_Th Indicates the theoretical number of ladles required; S2-2: The theoretical number of ladles N required according to calculation ladle_Th Round up to get the rounded-up number of ladles N ladle ; S2-3: According to the number of ladles N rounded up ladle Calculate the theoretical heat turnover time of the ladle, the calculation formula is as follows: T ladle =N ladle *1440 / N heat , where T ladle It indicates the theoretical thermal turnover time of the ladle; S2-4: Calculate the surplus time of ladle turnover capacity. The calculation formula is as follows: T excess =T ladle -T ladle_Th , where T excess Indicates the surplus time of ladle turnover capacity.

4. The method for optimizing the selection of three-furnace three-machine ladles according to claim 3, characterized in that: Step S2 also includes analyzing production fluctuations by counting the actual time differences of each process and judging whether the surplus time of the ladle turnover capacity is sufficient to cope with these fluctuations. The specific steps are as follows: S2-5: Count the difference between the actual start time and the planned start time, the actual end time and the planned end time of the converter, refining and continuous casting processes, the actual start time and the planned start time, the actual end time and the planned end time of the overhead crane, and count the distribution of the operation time difference; S2-6: Compare the relationship between the inevitable surplus time and the difference in operating time. When the inevitable surplus time is greater than the difference in operating time, it means that the surplus time of the current ladle can meet the fluctuation of production and no additional ladle is needed; when the inevitable surplus time is less than the difference in operating time, it means that the surplus time of the current ladle cannot meet the fluctuation of production and additional ladle is needed; the calculation formula for the theoretical number of ladles in the whole plant after the addition is as follows: N incre_Th =N heat *(T ladle_Th +T dis ) / 1440,N incre_Th It represents the theoretical number of ladles in the whole plant after the addition, T dis Indicates the job time difference.

5. The method for optimizing the selection of three-furnace three-machine ladles according to claim 1, characterized in that: In step S3: the preset scheduling rules include: ladle selection process constraints and experience rules and ladle selection priorities.

6. The method for optimizing the selection of three-furnace three-machine ladles according to claim 5, characterized in that: In the ladle selection process constraints and empirical rules, there are material matching constraints for the steel type of molten steel and the ladle. The requirements for the ladle material of the molten steel carried by the converter for the molten steel out of the converter include the selection of high-aluminum ladles, aluminum-magnesium-carbon ladles and magnesium-carbon ladles. Among them, when selecting a high-aluminum ladle, it is required that low-quality aluminum-magnesium-carbon or magnesium-carbon ladles cannot be selected, and if magnesium-carbon can be selected, aluminum-magnesium-carbon or high-aluminum ladles can also be selected; for the constraints on the steel type of the furnace for new ladles and cold ladles, the requirements for the selection of new ladles and cold ladles for specific molten steel are as follows: all new ladles and cold ladles are not allocated to low-phosphorus steel and low-temperature steel, and are preferentially allocated to ordinary carbon steel; the process path furnace plan requires that the age of the ladle is less than the rated maximum number of times; new ladles and cold ladles are not allocated to the first furnace of the continuous casting machine, the water change furnace, the shutdown furnace and the inverted ladle furnace.

7. The method for optimizing the selection of three-furnace three-machine ladles according to claim 5, characterized in that: In step S3: the ladle allocation priority is divided into priority 1-3, among which priority 1 represents the selection of temperature, referring to the temperature ladle selection priority, taking into account the above constraints; priority 2 represents the selection of ladle age, giving priority to ladle with high ladle age, which is taken offline at each maintenance node and new ladle is put online; priority 3 represents the selection of ladle number, giving priority to ladle with low ladle number, which has the lowest priority and is only used as an option for new ladle commissioning.

8. The method for optimizing the selection of three-furnace three-machine ladles according to claim 1, characterized in that: In step S3: based on the ladle selection process constraints and empirical rules and ladle matching priority constraints, after forming the corresponding available ladle set for the furnace, the dispatcher selects the optimal ladle according to the following performance indicators, completes the molten steel transfer plan, and reversely infers the ladle temperature according to the natural cooling time interval. The natural cooling time interval of the ladle refers to the waiting time between two consecutive ladle transfer cycles. The site judges the temperature of the ladle based on this residence time and determines the priority of the next activation.

9. The method for optimizing the selection of three-furnace three-machine ladles according to claim 8, characterized in that: The temperature of the ladle is judged by the residence time on site, and the priority of the next activation is determined. The specific priorities are as follows: Priority 1: With the goal of not increasing the turnover of the ladle, priority is given to the disabling and commissioning of the ladle, that is, offline cold repairs must be carried out and newly baked ladles must be put into use. If the number of casting machines is increased, new ladles must be put into use; Priority 2: The time interval for the natural cooling of the ladle is less than half an hour. The ladle has just completed a transfer, and the temperature of the ladle is the most ideal steel-bearing condition; Priority 3: The time interval for the natural cooling of the ladle is greater than a hour but less than b hours. This ladle only needs a short period of rapid baking before activation; Priority 4: The time interval for natural cooling of the ladle is selected to be greater than b hours and less than c hours. At this time, if the ladle is used, it needs to be preheated and baked for a period of time; preferred level 5: the time interval for natural cooling of the ladle is greater than c hours. At this time, the ladle has been completely cooled to a lower temperature, which is equivalent to a cold ladle, wherein a, b and c represent the time interval for natural cooling of the ladle.

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