Converter flue gas safety control and coal gas recovery optimization method and system

Abstract

The invention discloses a converter flue gas safety control and coal gas recovery optimization method and system, and relates to the technical field of time measurement. Flue gas circulation historical data of N times of historical flue gas circulation processes are collected in advance, the flue gas circulation historical data are stored in a retrieval database, and data retrieval conditions are set for the retrieval database; the method comprises the steps of collecting actual flue gas data in real time in the actual smelting process, evaluating the expected circulation duration of flue gas reaching a specified end point based on the actual flue gas data and the flue gas circulation model, and carrying out safety control and coal gas recovery based on the expected circulation duration. The problem that the travel time of the smoke from a measuring point to a specified point is difficult to estimate is solved.

Description

Technical Field

[0001] The invention relates to the technical field of time measurement, and in particular to a converter flue gas safety control and coal gas recovery optimization method and system. Background Art

[0002] At present, in the primary dust removal system of the converter, especially the dry electrostatic precipitator system, explosive flue gas is sometimes generated during the converter smelting process. After the explosive flue gas enters the dry electrostatic precipitator, electric sparks are generated inside the electric field, causing the dry electrostatic precipitator to explode. Severe explosion will cause serious damage to the inside of the dry electrostatic precipitator, resulting in production suspension for maintenance. At the same time, severe explosion will cause subsequent damage to equipment, such as fans and subsequent metal filter cartridges.

[0003] In addition, during the converter smelting process, when the oxygen concentration in the flue gas is less than 2% and the carbon monoxide concentration is greater than a certain value, the flue gas is recovered as coal gas into the gas tank. Generally, in the later stage of smelting, after the gun is raised, in order to prevent extreme safety accidents, the switching valve immediately switches the valve after receiving the gun raising signal to stop recovering coal gas. However, after the gun is raised, there is still a large amount of qualified coal gas in the pipeline. After the valve is switched, these qualified coal gases are discharged from the chimney into the ambient air, causing energy loss.

[0004] Therefore, in the case of the former explosive flue gas, it is necessary to design a method to measure the time from the measuring point to the designated point at the starting point and the end point of the explosive flue gas. Furthermore, in the case of explosion caused by electric sparks, after the explosive flue gas is found at the measuring point, the arrival time and departure time of the explosive flue gas to the electrostatic precipitator or the designated electric field inside the electrostatic precipitator can be calculated. Then, in the electric field where the explosive flue gas exists, the operating voltage can be shut down or reduced to prevent the generation of electric sparks, and further, prevent the explosion.

[0005] In the case of qualified coal gas recovery, the time when the end point of qualified flue gas reaches the switching valve from the measuring point is predicted, and then the time when the switching valve can be switched is accurately determined, and all qualified coal gas should be recovered.

[0006] To this end, the present invention proposes a converter flue gas safety control and gas recovery optimization method and system. Summary of the invention

[0007] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a converter flue gas safety control and gas recovery optimization method and system, which solves the problem of difficult estimation of the travel time of flue gas from a measuring point to a specified point.

[0008] To achieve the above purpose, a converter flue gas safety control and gas recovery optimization method is proposed, comprising the following steps:

[0009] Step 1: pre-collect the historical flue gas circulation data of the historical flue gas circulation process corresponding to N converter smelting processes, and save the historical flue gas circulation data to the retrieval database; N is the number of selected flue gas circulation tests;

[0010] Step 2: Setting data retrieval conditions for the retrieval database and optimizing the data to construct a smoke circulation model;

[0011] Step 3: During the actual smelting process, collect actual flue gas data in real time; based on the actual flue gas data and the flue gas circulation model, evaluate the expected circulation time for the flue gas to reach the specified end point, and perform safety control and gas recovery based on the expected circulation time;

[0012] The method for collecting the historical data of smoke circulation is as follows:

[0013] For each historical flue gas flow process corresponding to the converter smelting process, the starting time and ending time of the flue gas flow are collected;

[0014] Between the time starting point and the time ending point of each smoke flow process, the flow characteristic parameters of the smoke flow process are collected once at a preset collection interval;

[0015] Mark the collection intervals with levels;

[0016] During the entire smelting process of each historical flue gas flow process, the flow characteristic parameters collected at each level of collection interval are saved in a group of data groups, and the flow characteristic parameters collected at each level of collection interval are used as a data chain;

[0017] The data group and the corresponding data chain are saved in a database as smoke circulation history data;

[0018] The method of setting the data retrieval conditions for the retrieval database is:

[0019] Extract one or more levels from all circulation characteristic parameters except circulation time, extract one or more parameters in each level, and form a search chain; one search chain corresponds to one search condition;

[0020] The method of performing data optimization is as follows:

[0021] Optimization of multiple time t values ​​under the same data retrieval conditions;

[0022] Under the same search conditions, one or n historical occurrence chains can be retrieved, and the corresponding one or n time values ​​can be obtained; n is the number of time values ​​obtained;

[0023] The optimization of multiple time t values ​​includes: performing statistics on multiple time values, setting a landing probability value, and setting a confidence interval within a predetermined interval of the landing probability value; when the landing probability value is 100%, the confidence interval is an interval formed by the maximum and minimum values ​​of the time value; then optimizing the data retrieval condition, setting the subtraction value of the maximum and minimum values ​​to a specified value, retaining the data retrieval condition with a time range less than the specified value, and deleting the data retrieval condition with a time range greater than the specified value;

[0024] The method of constructing the smoke circulation model is:

[0025] The data group in the search database, the data chain formed by the multiple data groups and the data search conditions set for searching the database constitute the necessary smoke circulation model;

[0026] The method of real-time collection of actual flue gas data is:

[0027] In the actual smelting process, the moment when the gas detection system detects the characteristic flue gas is recorded as the actual start time and as the 0th level acquisition interval, and all the circulation characteristic parameters or part of the circulation characteristic parameters at the actual start time are recorded as the actual flue gas data of the 0th level acquisition interval;

[0028] At each collection interval, actual flue gas data of the corresponding level of collection interval is collected;

[0029] The method for evaluating the expected flow time for smoke to reach the specified end point based on actual smoke data and the smoke flow model is as follows:

[0030] During the smelting process, according to the data chain formed by the data group actually collected, the corresponding data chain in the database is found according to the single data retrieval condition or multiple data retrieval conditions set in the retrieval database; the data chain formed by the data group actually collected is compared with the data chain of the corresponding series in the database, and then, n data chains in the database that are approximately corresponding are obtained, and then a set of time values ​​and a confidence interval are formed from the n time values ​​from the actual start time to the end time corresponding to the n data chains from the database; when the result of subtracting the minimum value of the confidence interval from the maximum value is less than the specified value, the search is stopped.

[0031] Determine the time value according to the purpose and location of the search, such as the maximum value, the minimum value, or the average value;

[0032] If the data is found to be not completely matched during the search, the nearest value is used; that is, when the collected data is between the data in two databases, the nearest value is used to continue the matching;

[0033] Determine the time value based on the purpose of the search.

[0034] Determine the time value based on the purpose of the search.

[0035] A converter flue gas safety control and gas recovery optimization system is proposed, which includes a historical data collection module, a circulation model construction module and a circulation time estimation module; wherein each module is electrically connected;

[0036] A historical data collection module collects smoke flow historical data of N historical smoke flow processes in advance, and saves the smoke flow historical data to a search database; N is the number of selected smoke flow tests, and sends the search database to the flow model construction module;

[0037] The circulation model building module sets data retrieval conditions for the retrieval database and performs data optimization to build a smoke circulation model, and sends the smoke circulation model to the circulation time estimation module;

[0038] The circulation time estimation module collects actual flue gas data in real time during the actual smelting process; based on the actual flue gas data and the flue gas circulation model, it evaluates the expected circulation time for the flue gas to reach the specified end point, and performs safety control and gas recovery based on the expected circulation time.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The present invention collects the historical data of flue gas circulation during N historical flue gas circulation processes in advance, and saves the historical data to a retrieval database; N is the number of selected flue gas circulation tests; sets data retrieval conditions for the retrieval database, and performs data optimization to build a flue gas circulation model, collects actual flue gas data in real time during the actual smelting process; evaluates the expected circulation time for the flue gas to reach a specified end point based on the actual flue gas data and the flue gas circulation model, and performs safety control and gas recovery based on the expected circulation time; and realizes calculation without using specific parameters, and under the condition that the structure between the measuring point and the specified point is stable, according to F=m×a, and The matching relationship of each variable in the formula is used to find the smelting parameters related to the power F that pushes the flue gas forward, the parameters related to the flue gas flow acceleration a, the parameters related to the flue gas mass m, and the parameters related to the initial velocity v0. Then, by collecting a large amount of parameter data, a dynamic simulation model of the flue gas flow field is established, that is, a database relationship between time t and corresponding factors is established (F force related parameters and changes, various gas concentrations and changes in flue gas, flue gas volume and changes, smelting static model parameters, etc.). In this way, on this basis, there is no need for calculation, only through real-time measurement of relevant corresponding parameters and their changes, combined with the database and the dynamic simulation model of the flue gas flow field to accurately predict the time from the measurement point to the specified point. Then, the time when the explosive flue gas reaches the specified position inside the electrostatic precipitator and the time when the end point of the qualified coal gas in the pipeline reaches the switching valve after the gun is lifted are determined. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a flow chart of a converter flue gas safety control and gas recovery optimization method in Example 1 of the present invention;

[0042] Figure 2 This is a module connection relationship diagram of a converter flue gas safety control and gas recovery optimization system in Example 2 of the present invention. DETAILED DESCRIPTION

[0043] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than 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.

[0044] It should be noted that, in a theoretical embodiment, it can be based on the principle of kinetics, that is, F = m × a, and (where F is the power that pushes the smoke forward, m is the mass, a is the acceleration, S is the distance from the measurement point to the specified point, v0 is the initial velocity of the measurement point, and t is the time it takes for the characteristic smoke to travel from the measurement point to the specified point) to infer the time from the measurement point to the specified point;

[0045] However, the main driving force that affects the flue gas is the fan pulling force, the furnace gas generated during the converter smelting process, and the air inhaled from the furnace mouth. Moreover, during the entire smelting process, the intensity of the chemical reaction in the furnace varies at different stages, and the fan is set manually, resulting in different speeds at different stages. Therefore, the driving force F that pushes the flue gas forward is uncertain. Secondly, during the process of the flue gas moving forward, the temperature of the flue gas continues to drop due to the heat dissipation of the pipe in the environment, and the volume of the flue gas continues to shrink, making it difficult to derive the travel time of the flue gas from the measurement point to the specified point through a formula.

[0046] Furthermore, during the converter smelting process, a large amount of flue gas is generated. The flue gas is pulled by the fan power, passes through the conveying flue, and the vaporization flue, pipeline, dust removal equipment, fan, valve group, etc. located in the conveying pipeline to reach the chimney, and is discharged into the air, or when the concentration of CO and O2 in the flue gas reaches the specified recovery conditions, it is transported to the gas tank.

[0047] The system process of dry electrostatic precipitator for primary dust removal of converter includes converter, vaporization flue, evaporative cooling tower, dry electrostatic precipitator, fan, silencer, recovery gas concentration measurement system and switching valve. When the recovery gas concentration measurement system detects that the oxygen and carbon monoxide in the flue gas meet the gas recovery conditions, the switching valve switches the flue gas to the coal cooling and gas cabinet side. When the recovery gas concentration measurement system detects that the oxygen and carbon monoxide in the flue gas do not meet the gas recovery conditions, the switching valve switches the flue gas to the chimney side.

[0048] Temperature changes of flue gas: The temperature of flue gas coming out of the converter furnace is generally above 1300℃. It is cooled to about 200℃ through the vaporization flue and evaporative cooling tower. When it is transported to the electrostatic precipitator through the pipeline, the flue gas temperature is cooled to about 180℃. When it reaches the switching valve, the temperature drops to about 130℃. After the flue gas meets the recovery requirements, the switching valve switches the flue gas to the coal cooling and gas tank side. The flue gas is cooled to about 70℃ through the coal cooling and then enters the gas tank for storage.

[0049] During the flue gas transmission process, the temperature of the flue gas at the converter mouth is as high as 1300-1650℃. It passes through various pipeline transmission equipment and reaches the designated starting point. During the whole process, the temperature gradually decreases, and the cooling process is related to the ambient temperature. During the cooling process, the actual flue gas volume gradually decreases.

[0050] In the converter flue gas conveying system, there are pipelines and dust removal equipment. The dust removal equipment includes evaporative cooling towers, electrostatic precipitators and fans. The pipeline contains straight sections, elbows and various connecting pipes. The entire conveying pipeline system is complex. However, except for the following cases, the structures of these equipment are stable: (1) At the converter furnace mouth, some systems will install a skirt that can be lowered to adjust the secondary combustion; (2) The fan may adjust the air volume at different smelting stages; (3) The evaporative cooling tower will adjust the amount of water and medium injected in real time according to the outlet temperature.

[0051] Based on the above points, it is difficult for us to accurately calculate the time from the starting point to the specified end point through the calculation formula. Based on this, the present invention proposes the following embodiment of the converter flue gas safety control and gas recovery optimization method;

[0052] Specifically, the present invention uses a large amount of measurement data and smelting process parameters in each smelting process, collects parameters related to F, m, and v0, and collects the time t corresponding to these parameters, stores them in a storage device, and establishes a data model. In actual use, a set of actual values ​​and changes are detected by the detection system, and the data in the storage device is retrieved, or the processed data is included, and through tracking and comparison, t from the measurement point to the specified point is directly determined before the actual characteristic flue gas reaches the specified point.

[0053] Example 1

[0054] like Figure 1 As shown, a converter flue gas safety control and gas recovery optimization method comprises the following steps:

[0055] Step 1: pre-collect the historical flue gas circulation data of the historical flue gas circulation process corresponding to N converter smelting processes, and save the historical flue gas circulation data to the retrieval database; N is the number of selected flue gas circulation tests;

[0056] Step 2: Setting data retrieval conditions for the retrieval database and optimizing the data to construct a smoke circulation model;

[0057] Step 3: During the actual smelting process, collect actual flue gas data in real time; based on the actual flue gas data and the flue gas circulation model, evaluate the expected circulation time for the flue gas to reach the specified end point, and perform safety control and gas recovery based on the expected circulation time;

[0058] It should be noted that in order to collect historical data on flue gas circulation, several flue gas detection systems need to be installed in the converter flue gas delivery system before the historical flue gas circulation process is carried out;

[0059] Specifically, a gas detection system is installed at the front end or back end of the evaporative cooling tower, including concentration detection of various gases in the flue gas, flue gas flow detection, temperature detection, and pressure detection. It can be the detection of all of the above factors or only some of the factors, but it must include the detection of oxygen and carbon monoxide concentrations.

[0060] If the purpose is to detect explosive smoke from the detection system to a fixed point in the middle of the electrostatic precipitator, a gas concentration detection instrument must be installed on the front end pipe of the entrance of the electrostatic precipitator. The gas concentration detection instrument can be a single gas concentration detection or a multi-gas concentration detection group, among which oxygen or argon concentration detection instrument (at least one of the two must be installed) must be installed.

[0061] A gas concentration detection system is installed at the front end of the switching valve, among which oxygen and carbon monoxide concentration detection instruments must be installed.

[0062] In case of delayed gas recovery, it is not necessary to add a gas detection instrument (set) at the front end of the electrostatic precipitator.

[0063] Furthermore, the smoke flow historical data is collected in the following manner:

[0064] For each historical flue gas flow process corresponding to the converter smelting process, the starting time and the ending time of the flue gas flow are collected; preferably, the starting time includes but is not limited to starting from lowering the gun but is not limited to this moment, and the ending time is raising the gun but is not limited to the moment of raising the gun, for example, the end time is the completion point of the converter steelmaking.

[0065] Between the time starting point and the time ending point of each smoke flow process, the flow characteristic parameters of the smoke flow process are collected once at a preset collection interval;

[0066] The acquisition intervals are marked with levels; for example, starting from the time of gun drop, the moment of gun drop is defined as level 0, the first time interval after gun drop is defined as level 2, and so on;

[0067] During the entire smelting process of each historical flue gas flow process, the flow characteristic parameters collected at each level of collection interval are saved in a group of data groups, and the flow characteristic parameters collected at each level of collection interval are used as a data chain;

[0068] The data group and the corresponding data chain are saved in a database as smoke circulation history data;

[0069] Specifically, the collection method of the flow characteristic parameters is:

[0070] Through the smoke detection system installed at the designated location, the detection includes but is not limited to: smoke volume, gas concentration, input parameters of inert gas in the smelting process, circulation time of smoke, composition and circulation characteristic parameters, etc.;

[0071] It should be noted that the above-mentioned flow characteristic parameters can be all parameters collected or manual partial parameters collected during the actual collection process;

[0072] Furthermore, the method of setting the data search conditions for the search database is:

[0073] Extract one or more levels from all circulation characteristic parameters except circulation time, extract one or more parameters in each level, and form a search chain; one search chain corresponds to one search condition;

[0074] In a preferred embodiment, the data optimization method is:

[0075] Under the same data retrieval conditions, multiple time t values ​​are optimized; under the same retrieval conditions, 1 or n historical occurrence chains can be retrieved and the corresponding 1 or n time values ​​can be obtained.

[0076] The optimization of multiple time t values ​​includes: performing statistics on multiple time values, setting a landing probability value, and setting a confidence interval within a predetermined interval of the landing probability value; when the landing probability value is 100%, the confidence interval is an interval formed by the maximum and minimum values ​​of the time value; then optimizing the data retrieval condition, setting the subtraction value of the maximum and minimum values ​​to a specified value, retaining the data retrieval condition with a time range less than the specified value, and deleting the data retrieval condition with a time range greater than the specified value;

[0077] In a preferred embodiment, the method of performing data optimization further includes:

[0078] Extract the time interval t from the time start point to the time end point under the same search conditions in the search database, exclude the data groups and data chains corresponding to the same time value, reduce the capacity of the database, and shorten the time of later search;

[0079] Furthermore, the method of constructing the smoke circulation model is:

[0080] The data groups in the search database, the data chains in each data group and the data search conditions set for searching the database constitute the necessary smoke circulation model;

[0081] Further preferably, the flue gas circulation model further comprises a data calculation method, that is, a method for further calculation after taking a value from the database at time t; the method is related to the process flow adopted by the specific smelting process;

[0082] Furthermore, the method of collecting actual flue gas data in real time is:

[0083] In the actual smelting process, the moment when the gas detection system detects the characteristic flue gas is recorded as the actual start time and as the 0th level collection interval, and all the circulation characteristic parameters or part of the circulation characteristic parameters at the actual start time are recorded as the actual flue gas data of the 0th level collection interval; the specific number of circulation characteristic parameters collected is determined according to actual needs;

[0084] At each collection interval, actual flue gas data of the corresponding level of collection interval is collected;

[0085] Furthermore, the method for evaluating the expected flow time for the smoke to reach the specified end point based on the actual smoke data and the smoke flow model is:

[0086] During the smelting process, according to the data chain formed by the data group actually collected, the corresponding data chain in the database is searched according to the single data search condition or multiple data search conditions set in the search database. The data chain formed by the data group actually collected is shorter than the data chain in the database, and then the corresponding data chains in the n databases are obtained, and then the n time values ​​corresponding to the n data chains from the actual start time to the end time are formed to form a set of time values ​​and a confidence interval; when the result of the maximum value minus the minimum value of the confidence interval is less than the specified value, the search is stopped;

[0087] Determine the value according to the purpose and location of the search, that is, take the maximum value or the minimum value; the determination of the value according to the purpose and location of the search is based on the safety principle, for example, for the safety protection of explosive gas, for the characteristic flue gas at the starting point, take the minimum value of the confidence interval, and for the characteristic flue gas at the end point, take the maximum value of the confidence interval;

[0088] If it is found during the search that the data is not completely matched, the nearest value is taken; that is, when the collected data is located between the data in two databases, the pairing will continue according to the nearest value.

[0089] Determine the value of t according to the purpose of detecting t;

[0090] In the actual retrieval process, it is not necessary to perform retrieval pairing from the 0th level collection interval, but it is possible to agree to start retrieval pairing from the preset kth level;

[0091] Furthermore, the method of performing safety control and gas recovery based on the expected circulation time is:

[0092] Based on actual retrieval needs, corresponding controls are carried out before the expected circulation time. For example, for explosive gases, the voltage is reduced in advance to prevent electric sparks from occurring to ensure the passage of explosive smoke.

[0093] The above data calculation method and a specific method for measuring the time value are shown in the following example:

[0094] For applications involving explosive fumes.

[0095] Set an explosive range for explosive smoke. For example, set the explosive concentration range of oxygen to [5%, 7%] and the explosive range of carbon monoxide to [8%, 12%].

[0096] When the gas detection system detects that the concentration values ​​of oxygen and carbon monoxide fall into these two explosive ranges at the same time, the flue gas is defined as explosive flue gas.

[0097] When the gas detection system first detects explosive smoke, this moment is defined as the starting point of the explosive smoke. When the gas detection system detects that the explosive smoke leaves the gas detection system, this moment is defined as the ending point of the explosive smoke.

[0098] At this time, you can perform single gas tracking, i.e. parameter collection, or multi-gas tracking, i.e. parameter collection. In this case, single gas tracking is used, i.e. tracking of oxygen concentration, i.e. collecting the starting and ending points of oxygen concentration entering and leaving the smoke gas explosive zone.

[0099] For the characteristic flue gas at the starting point, the t value from the gas detection system to the detection system at the front end of the electrostatic precipitator can be determined through database retrieval. Based on the principle of safety, the minimum value and the t value that reaches the detection point at the front end of the electrostatic precipitator the fastest are taken, as well as the time t1 from the detection point at the front end of the electrostatic precipitator to the detection point at the front end of the valve. Similarly, the t1 value also contains the maximum and minimum values. Based on the principle of safety, the minimum value is taken, that is, the fastest passing time value;

[0100] For the characteristic flue gas at the termination point, the t value of the detection system from the gas detection system to the front end of the electrostatic precipitator can be determined through database retrieval. Based on the principle of safety, the maximum value and the slowest t value to reach the detection point at the front end of the electrostatic precipitator, as well as the time t2 from the front end detection point of the electrostatic precipitator to the front end detection point of the valve, are taken. Similarly, the t2 value also contains the maximum and minimum values. According to the safety principle, the maximum value, that is, the slowest lag time value, is taken.

[0101] Temperature measuring instruments were installed at the front and rear ends of the electrostatic precipitator, and the inlet temperature was measured to be 160°C and the outlet temperature to be 130°C. According to the gas state equation, it can be approximately considered that: the inlet flue gas volume due to temperature drop / the outlet flue gas volume = (273+130) / (273+160) = 403 / 433 = 0.93, so it can be approximately considered that the volume of the flue gas has not changed.

[0102] The structure of the electrostatic precipitator is that the inlet and outlet are bell-shaped, and the four electric fields are supported by five ring beams. The flue gas passes through the inlet bell-shaped mouth, the first ring beam, the first electric field, the second ring beam, the second electric field, the third ring beam, the third electric field, the fourth ring beam, the fourth electric field, the fifth ring beam, and the bell outlet in sequence. The diameter of the ring beam is smaller than the diameter of the electric field. The diameter of the inlet and outlet pipes is the same. The diameter of the pipe is 2 meters, the diameter of the electric field is 10 meters, and the diameter of the ring beam is 9 meters. The distance between the small openings of the inlet and outlet bell-shaped mouths is 26 meters, the horizontal length of the electric field is 4 meters, and the horizontal length of the ring beam is 2 meters.

[0103] It can be approximately considered that the flue gas moves at a uniform speed in the electrostatic precipitator. At the same time, the electrostatic precipitator can be approximately divided into four expanded electric fields. That is, from the entrance to the center of the second ring beam is the first approximate electric field, from the center of the second ring beam to the center of the third ring beam is the second approximate electric field, from the center of the third ring beam to the center of the fourth ring beam is the third approximate electric field, and from the center of the fourth ring beam to the center of the fifth ring beam is the fourth approximate electric field.

[0104] Calculate the time it takes for the oxygen characteristic flue gas with an explosive range of [5%, 7%] to enter and leave the first approximate electric field.

[0105] The length of the first approximate electric field is 2+4+1=7 (meters);

[0106] The distance from the detection point at the front end of the ESP to the entrance of the ESP is 2 meters, and the distance from the detection point at the front end of the switching valve to the exit of the ESP is 10 meters. They can be approximately ignored.

[0107] When explosive flue gas is detected at the front-end detection point, the parameters related to F, m, and v0 are tracked at intervals of 30 seconds for the characteristic flue gas at the starting point and the ending point (the oxygen concentrations are 7% and 5% respectively, the former is the concentration value at the starting point, and the latter is the concentration value at the ending point). At the beginning of the 10th level of collection, the collected data is compared with the data in the database to obtain a combination of the time t1 value from the front-end detection point to the front-end detection point of the electrostatic precipitator, and the corresponding time t2 from the front-end detection point of the electrostatic precipitator to the back-end detection point of the electrostatic precipitator.

[0108] For the starting point, the combination of t1 values ​​from the front detection point to the detection point at the front end of the electrostatic precipitator is obtained, and the interval of t1 values ​​is [200, 204], in seconds. The interval of t2 values ​​from the detection point at the front end of the electrostatic precipitator to the detection point at the rear end of the electrostatic precipitator is [20, 24], in seconds.

[0109] Therefore, based on the principle of safety, it can be determined that the time to enter the first approximate electric field is from the moment the explosive smoke is detected, and the first approximate electric field of the electrostatic precipitator is entered at the 200th second. Therefore, based on the principle of safety, the voltage of the electrostatic precipitator is reduced to 30,000 volts (the voltage without electric sparks) 2 seconds in advance from the moment the explosive smoke is detected, before the 200th second, to ensure the passage of the explosive smoke.

[0110] For the termination point, a combination of t1 values ​​from the front-end detection point to the rear-end detection point of the electrostatic precipitator is obtained, the interval of t1 values ​​is [230, 234], in seconds, and the corresponding interval of time t2 values ​​from the front-end detection point of the electrostatic precipitator to the rear-end detection point of the electrostatic precipitator is [20, 24], in seconds.

[0111] From the safety principle, the value is 234, that is, considering the interval of the time t2 value as [20, 24], that is, the total time interval through the four approximate electric fields is [20, 24]. From the safety point of view, the value is 24, that is, the time to pass through the first approximate electric field is: 24×the length of the first approximate electric field / the length of the entire electrostatic precipitator=24×7 / 26=6.5 (seconds), that is, the time for the explosive smoke to leave the first approximate electric field can be determined to be 234+6.5=240.5 seconds. Therefore, from the time when the explosive smoke is found at the front-end detection point, at the 240.5 second moment, the first electric field is re-boosted to the original voltage for effective dust removal.

[0112] By analogy, the voltage reduction moment and voltage increase moment from the second electric field to the fourth electric field are obtained.

[0113] A solution for delayed gas recovery after the gun is lifted in the later stage of smelting.

[0114] The condition for terminating gas recovery is set as oxygen concentration greater than 2%, that is, recovery must be stopped.

[0115] In the later stage of smelting, close to the time of lifting the gun, the gas detection system found characteristic flue gas, that is, the flue gas concentration was 2%, and the time from the start of lowering the gun to the discovery of the characteristic flue gas was recorded as 610 seconds. The system issued a gun lifting signal, and recorded 700 seconds from the start of lowering the gun to the time of lifting the gun.

[0116] From the discovery of characteristic flue gas, data tracking is carried out, that is, the gas detection system collects parameters related to F, m, and v0, and tracks and collects data every 30 seconds. At the same time, according to the search conditions set in the database, the database is searched and compared to obtain a set of time values ​​from the front-end detection point to the valve detection point. After tracking the 40th level, after conversion, it is found that the set of time values ​​from the moment the gun is lowered and from the front-end detection point to the valve detection point is [740, 744]. The search is terminated, and the initial delay time is taken from the safety principle as 740 seconds - 700 seconds = 40 seconds. The time required for the valve to completely complete the switching action is 4 seconds, and the safety guarantee time is 6 seconds. Therefore, starting from the moment of lifting the gun, 40-4-6 = 30 (seconds), that is, after the gun lifting signal appears, the valve switching action is delayed by 30 seconds to switch the flue gas from the recovery gas end to the chimney emission end.

[0117] Example 2

[0118] like Figure 2 As shown, a converter flue gas safety control and gas recovery optimization system includes a historical data collection module, a circulation model construction module and a circulation time estimation module; wherein each module is electrically connected;

[0119] A historical data collection module collects smoke flow historical data of N historical smoke flow processes in advance, and saves the smoke flow historical data to a search database; N is the number of selected smoke flow tests, and sends the search database to the flow model construction module;

[0120] The circulation model building module sets data retrieval conditions for the retrieval database and performs data optimization to build a smoke circulation model, and sends the smoke circulation model to the circulation time estimation module;

[0121] The circulation time estimation module collects actual flue gas data in real time during the actual smelting process. Based on the actual flue gas data and the flue gas circulation model, it evaluates and predicts the expected circulation time for the flue gas to reach the specified end point in real time, and performs safety control and gas recovery based on the expected circulation time.

[0122] The above preset parameters or preset thresholds are all set by technicians in this field according to actual conditions or obtained through large-scale data simulation.

[0123] The above embodiments are only used to illustrate the technical method of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical method of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A converter flue gas safety control and gas recovery optimization method, characterized in that: The following steps are involved: Step 1: pre-collect the historical flue gas circulation data of the historical flue gas circulation process corresponding to N converter smelting processes, and save the historical flue gas circulation data to the retrieval database; N is the number of selected flue gas circulation tests; Step 2: Setting data retrieval conditions for the retrieval database and optimizing the data to construct a smoke circulation model; Step 3: During the actual smelting process, collect actual flue gas data in real time; Based on actual flue gas data and the flue gas circulation model, the expected circulation time for the flue gas to reach the specified end point is evaluated, and safety control and gas recovery are performed based on the expected circulation time.

2. A converter flue gas safety control and gas recovery optimization method according to claim 1, characterized in that: The method for collecting the historical data of smoke circulation is as follows: For each historical flue gas flow process corresponding to each converter smelting process, the starting time and ending time of the flue gas flow are collected; Between the time starting point and the time ending point of each smoke flow process, the flow characteristic parameters of the smoke flow process are collected once at a preset collection interval; Mark the collection intervals with levels; During the entire smelting process of each historical flue gas flow process, the flow characteristic parameters collected at each level of collection interval are saved in a group of data groups, and the flow characteristic parameters collected at each level of collection interval are used as a data chain; The data group and the corresponding data chain are saved in the database as smoke circulation history data.

3. A converter flue gas safety control and gas recovery optimization method according to claim 2, characterized in that: The method of setting the data retrieval conditions for the retrieval database is: One or more parameters are extracted from all circulation characteristic parameters except the circulation time to form a search chain; one search chain corresponds to one search condition.

4. A converter flue gas safety control and gas recovery optimization method according to claim 3, characterized in that: The method for data optimization is as follows: Optimization of multiple time t values ​​under the same data retrieval conditions; The optimization of multiple time t values ​​includes: performing statistics on multiple time values, setting a landing probability value, and setting it as a confidence interval within a predetermined interval range of the landing probability value; when the landing probability value is 100%, the confidence interval is an interval formed by the maximum and minimum values ​​of the time value; then optimizing the data retrieval conditions, setting the subtraction value of the maximum and minimum values ​​to a specified value, retaining the data retrieval conditions with a time range less than the specified value, and deleting the data retrieval conditions with a time range greater than the specified value.

5. A converter flue gas safety control and gas recovery optimization method according to claim 4, characterized in that: The method of constructing the smoke circulation model is: The data groups in the retrieval database, the data chains formed by the series of data groups, and the data retrieval conditions set for the retrieval database constitute the smoke circulation model.

6. A converter flue gas safety control and gas recovery optimization method according to claim 5, characterized in that: The method of real-time collection of actual flue gas data is: In the actual smelting process, the moment when the gas detection system detects the characteristic flue gas is recorded as the actual start time and as the 0th level acquisition interval, and all the circulation characteristic parameters or part of the circulation characteristic parameters at the actual start time are recorded as the actual flue gas data of the 0th level acquisition interval; The actual flue gas data of the corresponding level of collection interval is collected at the duration of each collection interval.

7. A converter flue gas safety control and gas recovery optimization method according to claim 6, characterized in that: The method for evaluating the expected flow time for smoke to reach the specified end point based on actual smoke data and the smoke flow model is as follows: In the smelting process, according to the data chain formed by the data group actually collected, according to the single data search condition or multiple data search conditions set in the search database, the corresponding data chain in the database is searched; the data chain formed by the data group actually collected is shorter than the data chain in the database, and then, the corresponding data chains in the n databases are obtained, and then the n time values ​​corresponding to the n data chains from the database from the actual start time to the end time are formed to form a set of time values ​​and a confidence interval; when the result of the maximum value minus the minimum value of the confidence interval is less than the specified value, the search is stopped; n is the number of time values ​​obtained; Determine the time value based on the purpose and location of the search; If the data is found to be not completely matched during the search, the nearest value is used; that is, when the collected data is between the data in two databases, the nearest value is used to continue the matching; Determine the time value based on the purpose of the search.

8. A converter flue gas safety control and gas recovery optimization system, which is used to implement the converter flue gas safety control and gas recovery optimization method according to any one of claims 1 to 7, characterized in that: It includes a historical data collection module, a circulation model building module and a circulation time estimation module; wherein each module is electrically connected; A historical data collection module collects smoke flow historical data of N historical smoke flow processes in advance, and saves the smoke flow historical data to a search database; N is the number of selected smoke flow tests, and sends the search database to the flow model construction module; The circulation model building module sets data retrieval conditions for the retrieval database and performs data optimization to build a smoke circulation model, and sends the smoke circulation model to the circulation time estimation module; The circulation time estimation module collects actual flue gas data in real time during the actual smelting process. Based on the actual flue gas data and the flue gas circulation model, it evaluates and predicts the expected circulation time for the flue gas to reach the specified end point in real time, and performs safety control and gas recovery based on the expected circulation time.

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