A method and system for optimizing the safety control of converter flue gas and gas recovery

Abstract

The present invention discloses a converter flue gas safety control and gas recovery optimization method and system, which relates to the technical field of time measurement. By pre-collecting the flue gas circulation historical data of N historical flue gas flow processes and storing the flue gas circulation historical data in a retrieval database, data retrieval conditions are set for the retrieval database and data optimization is performed to construct a flue gas circulation model. During the actual smelting process, actual flue gas data is collected in real time. Based on the actual flue gas data and the flue gas circulation model, the expected circulation duration for the flue gas to reach a specified end point is evaluated, and safety control and gas recovery are performed based on the expected circulation duration. It solves the problem that it is difficult to estimate the travel time of the flue gas from the measurement point to the specified point.

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 for 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: statistically analyzing multiple time values, setting a landing probability value, and setting it as a confidence interval within a pre-specified range of the landing probability value; when the landing probability value is 100%, the confidence interval is the interval formed by the maximum and minimum time values; then optimizing the data retrieval conditions, setting the subtraction value of the maximum and minimum values as 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.

[0024] The method for constructing the flue gas flow model is as follows:

[0025] Retrieving data groups in the database, the data chain formed by multiple data groups, and the data retrieval conditions set for the database constitute the necessary flue gas flow model.

[0026] The method for real-time collecting actual flue gas data is as follows:

[0027] During the actual smelting process, the moment when the gas detection system detects the characteristic flue gas is recorded as the actual start time and used as the 0th-level collection interval, and all or part of the circulation characteristic parameters at the actual start time are recorded as the actual flue gas data for the 0th-level collection interval.

[0028] At each collection interval duration, the actual flue gas data for the corresponding level collection interval is collected.

[0029] The method for evaluating the expected circulation duration of the flue gas reaching the specified end point based on the actual flue gas data and the flue gas flow model is as follows:

[0030] During the smelting process, according to the data chain formed by the actually collected data groups, and in accordance with the single data retrieval condition or multiple data retrieval conditions set in the database, the corresponding data chain in the database is searched for; the data chain formed by the actually collected data groups is compared with the corresponding level data chain in the database, and then, n corresponding data chains in the database are obtained. Furthermore, n time values from the actual start time to the time end point corresponding to the n data chains from the database form a set of time values and a confidence interval; when the result of subtracting the minimum value from the maximum value of the confidence interval is less than the specified value, the retrieval stops.

[0031] Determine the time value selection according to the purpose and location of the retrieval. For example, select the maximum value, the minimum value, or the average value.

[0032] When it is found that the data does not match completely during the retrieval, take the nearest value; that is, when the collected data is between two database data, continue the pairing according to the nearest value.

[0033] Determine the selection of the time value according to the purpose of the retrieval.

[0034] Determine the value of the time value according to the purpose of retrieval.

[0035] A converter gas safety control and gas recovery optimization system is proposed, including a historical data collection module, a flow model construction module, and a flow duration estimation module; among them, each module is connected electrically.

[0036] The historical data collection module pre-collects the flue gas flow historical data of N historical flue gas flow processes, and saves the flue gas flow historical data to the retrieval database; N is the number of selected flue gas flow tests, and sends the retrieval database to the flow model construction module.

[0037] The flow model construction module sets data retrieval conditions for the retrieval database and performs data optimization to construct a flue gas flow model, and sends the flue gas flow model to the flow duration estimation module.

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

[0039] Compared with the prior art, the beneficial effects of the present invention are:

[0040] The present invention pre-collects the flue gas flow historical data of N historical flue gas flow processes, and saves the flue gas flow historical data to the retrieval database; N is the number of selected flue gas flow tests; sets data retrieval conditions for the retrieval database and performs data optimization to construct a flue gas flow model, during the actual smelting process, collects actual flue gas data in real time; based on the actual flue gas data and the flue gas flow model, evaluates the expected flow duration for the flue gas to reach the specified end point, and performs safety control and gas recovery based on the expected flow duration; realizes without calculating with specific parameters, and under the condition of stable structure between the measurement point and the specified point, according to F = m×a, and For the matching relationships of various variables in the formula, find the smelting parameters related to the driving force F for pushing 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, establish a dynamic simulation model of the flue gas flow field, that is, establish the database relationship between time t and corresponding factors (parameters related to force F and their changes, concentrations and changes of various gases in the flue gas, flue gas volume and its changes, static model parameters of smelting, etc.). In this way, on this basis, without calculation, only by measuring relevant corresponding parameters and their changes in real time, combined with the database and the dynamic simulation model of the flue gas flow field, accurately predict the time from the measurement point to the specified point. Furthermore, determine 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 gas in the pipeline reaches the switching valve after the lance is lifted. Brief Description of the Drawings

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

[0042] Figure 2 It is a module connection relationship diagram of a converter flue gas safety control and gas recovery optimization system in Embodiment 2 of the present invention. Detailed Embodiment

[0043] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments. Obviously, the described embodiments are only a 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 those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0044] It should be noted that in a theoretical embodiment, based on the kinetic principle, that is, F = m×a, and (where F is the driving force for pushing the flue gas 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 for the characteristic flue gas to travel from the measurement point to the specified point), to speculate the time from the measurement point to the specified point;

[0045] However, since the driving force affecting the forward movement of the flue gas is mainly the fan pulling force and the furnace gas generated during the converter smelting process and the air inhaled at the furnace mouth, and moreover, during the entire smelting process, due to the different intensities of chemical reactions in the furnace at different stages, and the fan is set manually resulting in different speeds at different stages. Therefore, the driving force F for pushing the flue gas forward is uncertain. Secondly, during the forward movement of the flue gas, due to heat dissipation of the pipeline in the environment, the temperature of the flue gas continuously drops, and the volume of the flue gas also continuously shrinks and other reasons, it is very difficult to deduce and calculate the travel time of the flue gas from the measurement point to the specified point through the formula.

[0046] Moreover, during the converter smelting process, a large amount of flue gas is generated. The flue gas is tractioned by the power of the fan, passes through the conveying flue, as well as the vaporization flue, pipeline, dust removal equipment, fan, valve group, etc. located in the conveying pipeline, reaches 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 conveyed to the gas holder.

[0047] System process of dry electrostatic precipitation for primary dust removal in converter: converter, vaporization flue, evaporation cooling tower, dry electrostatic precipitator, fan, silencer, recovered gas concentration measurement system, switching valve. When the recovered 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 side of the coal cooler and gas holder. When the recovered 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 side of the chimney.

[0048] Temperature change of the flue gas: The flue gas coming out of the converter furnace mouth generally has a temperature above 1300 °C. After passing through the vaporization flue and evaporation cooling tower, it is cooled down to about 200 °C. When it is conveyed to the electrostatic precipitator through the pipeline, the temperature of the flue gas is cooled down to about 180 °C. When it reaches the switching valve, the temperature drops to about 130 °C. After the flue gas meets the recovery requirements, the switching valve switches the flue gas to the side of the coal cooler and gas holder. The flue gas is cooled down to about 70 °C after passing through the coal cooler and then enters the gas holder for storage.

[0049] During the transmission process of the flue gas, the temperature of the flue gas at the converter furnace mouth is as high as between 1300 - 1650 °C. Through various pipeline transmission equipment, it reaches the specified starting point. During the whole process, it is a process of gradually cooling down, and the cooling process is also related to the ambient temperature. During the cooling process, the actual flue gas volume of the flue gas gradually decreases.

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

[0051] Based on the above points, it is very difficult for us to accurately calculate the time from the starting point to the specified end point through calculation formulas. 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, as well as the corresponding time t of these parameters, stores them in a storage device, and establishes a data model. In actual application, a set of actual occurrence values and changes are detected by a detection system, the data in the storage device is retrieved, or the processed data is included. By tracking and comparing, before the actual characteristic flue gas reaches the specified point, the t from the measurement point to the specified point is directly determined.

[0053] Embodiment 1

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

[0055] Step 1: Collect historical flue gas flow data corresponding to N converter smelting processes in advance, and save the historical flue gas flow data to a retrieval database; N is the number of selected flue gas flow tests;

[0056] Step 2: Set data retrieval conditions for the retrieval database and perform data optimization to construct a flue gas flow 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 flow model, evaluate the expected flow duration for the flue gas to reach the specified end point, and perform safety control and gas recovery based on the expected flow duration.

[0058] It should be noted that in order to collect historical flue gas flow data, several flue gas detection systems need to be installed in the converter flue gas transmission system before the historical flue gas flow process.

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

[0060] If it is for the case of detecting explosive flue gas from the detection system to a fixed point position in the middle of the electrostatic precipitator, a gas concentration detection instrument must be installed on the front pipeline at the inlet of the electrostatic precipitator. The gas concentration detection instrument can be a single gas concentration detection or a multi-gas concentration detection group, and at least one of the oxygen or argon concentration detection instruments must be installed.

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

[0062] In the case of the delay time for gas recovery, a gas detection instrument (group) may not be added at the front end of the electrostatic precipitator.

[0063] Furthermore, the method for collecting the historical data of the flue gas flow is as follows:

[0064] For each historical flue gas flow process corresponding to a converter smelting process, collect the start time point and end time point of the flue gas flow; preferably, the start time point includes but is not limited to starting from the lowering of the lance but not limited to that moment, and the end time point is the raising of the lance but not limited to the raising moment. For example, the termination time is the completion point of tapping the converter.

[0065] Between the start time point and end time point of each flue gas flow process, collect the flow characteristic parameters of the flue gas flow process once every preset collection interval duration;

[0066] Mark the level of the collection interval; for example, starting from the lowering of the lance, the lowering moment is defined as level 0, and the first time interval after the lowering of the lance is defined as level 2, and so on;

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

[0068] The data group and the corresponding data chain are saved as the historical data of the flue gas flow in the database;

[0069] Specifically, the method for collecting the flow characteristic parameters is as follows:

[0070] Through the flue gas detection system installed at the specified position, detect including but not limited to: the flue gas volume of the flue gas, the gas concentration, the input parameters of the inert gas during the smelting process, and the flow duration of the flue gas, which constitute the flow characteristic parameters, etc.;

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

[0072] Furthermore, the method for setting the data retrieval conditions for the retrieval database is as follows:

[0073] Extract one or more levels from all the flow characteristic parameters except the flow duration, and extract 1 or several parameters in each level to form a retrieval chain; one retrieval chain corresponds to one retrieval condition;

[0074] In a preferred embodiment, the method for performing data optimization is as follows:

[0075] Optimization of multiple time t values under the same data retrieval conditions; 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: statistically analyzing multiple time values, setting a landing probability value, and setting it as a confidence interval within a preset range of the landing probability value; when the landing probability value is 100%, the confidence interval is the interval formed by the maximum and minimum time values; then optimize the data retrieval conditions, set the subtraction value of the maximum and minimum values as a specified value, retain the data retrieval conditions with a time range less than the specified value, and delete the data retrieval conditions with a time range greater than the specified value.

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

[0078] Under the same retrieval conditions in the retrieval database, extract the time interval t from the start time to the end time, exclude the data groups and data chains corresponding to the same time values, reduce the capacity of the database, and reduce the time for later retrieval.

[0079] Further, the method of constructing the flue gas flow model is:

[0080] Retrieve the data groups in the database, the data chains in each data group, and the data retrieval conditions set for the retrieval database to form a necessary flue gas flow model.

[0081] Further preferably, the flue gas flow model further includes a data operation method, that is, the method that needs to be further operated after taking the time t from the database; this method is related to the process flow adopted by the specific smelting process.

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

[0083] During the actual smelting process, record the moment when the gas detection system detects the characteristic flue gas as the actual start time, and use it as the 0th-level collection interval, and record all or part of the flow characteristic parameters at the actual start time as the actual flue gas data for the 0th-level collection interval; the specific number of collected flow characteristic parameters is determined according to actual needs.

[0084] At each collection interval duration, collect the actual flue gas data for the corresponding level of collection interval.

[0085] Further, the method of evaluating the expected flow duration of the flue gas reaching the specified end point based on the actual flue gas data and the flue gas flow model is:

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

[0087] Determine the value to be taken according to the purpose and location of the retrieval, that is, take the maximum value or the minimum value; the determination of the value to be taken according to the purpose and location of the retrieval is based on the safety principle. For example, for the safety protection purpose of explosive gases, 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 termination point, take the maximum value of the confidence interval;

[0088] When it is found that the data does not match completely during the retrieval, take the value of the nearest one; that is, when the collected data is between two database data, continue the pairing according to the value of the nearest one.

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

[0090] During the actual retrieval process, it is possible not to start the retrieval pairing from the 0th level of acquisition interval, but it can be agreed to start the retrieval pairing from the preset kth level;

[0091] Furthermore, the method of safety control and gas recovery based on the expected circulation duration is as follows:

[0092] Based on the actual retrieval requirements, corresponding control is carried out before the expected circulation duration. For example, for explosive gases, the voltage is reduced in advance to prevent the occurrence of electric sparks to ensure the passage of explosive flue gas.

[0093] A specific calculation method of the above data operation method and time value is shown in the following example:

[0094] Application for explosive flue gas.

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

[0096] When the gas detection system detects that the concentration values of oxygen and carbon monoxide both fall within these two explosive intervals, define the flue gas as explosive flue gas.

[0097] When the gas detection system first detects explosive flue gas, this moment is defined as the starting point of the explosive flue gas. When the gas detection system detects the explosive flue gas leaving the gas detection system, it is defined as the ending point of the explosive flue gas.

[0098] At this time, single-gas tracking, that is, parameter acquisition, or multi-gas tracking, that is, parameter acquisition, can be carried out. In this case, single-gas tracking is adopted, that is, the tracking of oxygen concentration, that is, the starting point and ending point values of the oxygen concentration value entering and leaving the explosive range of the flue gas are collected.

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

[0100] For the characteristic flue gas at the ending point, through database retrieval, the t value from the gas detection system to the detection system at the front end of the electrostatic precipitator can be determined. Starting from the safety principle, the maximum value is taken, that is, the t value that reaches the detection point at the front end of the electrostatic precipitator slowest, and the time t2 between the detection point at the front end of the electrostatic precipitator and the detection point at the front end of the valve. Similarly, this t2 value also includes the maximum and minimum values. According to the safety principle, the maximum value is taken, that is, the slowest lag passing time value.

[0101] Temperature measuring instruments are installed at the front end and the rear end of the electrostatic precipitator. The measured inlet temperature is 160 °C and the outlet temperature is 130 °C. According to the gas state equation, it can be approximately considered that: the inlet flue gas volume / outlet flue gas volume due to temperature drop = (273 + 130) / (273 + 160) = 403 / 433 = 0.93. Therefore, 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 mouths. Four electric fields are supported by five ring beams. The flue gas passes through the inlet bell 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 turn. Among them, the diameter of the ring beam is smaller than the diameter of the electric field. The diameters of the inlet and outlet pipes are the same. The pipe diameter is 2 meters, the electric field diameter is 10 meters, and the ring beam diameter is 9 meters. The distance between the small openings of the inlet and outlet bell 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 travels at a constant speed in the electrostatic precipitator. At the same time, the electrostatic precipitator can be approximately divided into four extended electric fields. That is, from the inlet 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 for the characteristic flue gas with an oxygen concentration in the 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 (m);

[0106] The distance from the detection point at the front end of the electrostatic precipitator to the inlet of the electrostatic precipitator is 2 m, and the distance from the detection point at the front end of the switching valve to the outlet of the electrostatic precipitator is 10 m. These can be approximately ignored.

[0107] After the explosive flue gas is detected at the front-end detection point, the parameters related to F, m, and v0 of the characteristic flue gas at the starting point and the ending point (with oxygen concentrations of 7% and 5% respectively, the former being the concentration value at the starting point and the latter being the concentration value at the ending point) are tracked every 30 seconds. Starting from the 10th-level acquisition, 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 rear-end detection point of the electrostatic precipitator.

[0108] For the starting point, a combination of t1 values from the front-end detection point to the front-end detection point of the electrostatic precipitator is obtained. The range of t1 values is [200, 204], with the unit of seconds. The range of 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], with the unit of seconds.

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

[0110] For the ending 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 range of t1 values is [230, 234], with the unit of seconds, and the corresponding range of the time t2 value from the front-end detection point of the electrostatic precipitator to the rear-end detection point of the electrostatic precipitator is [20, 24], with the unit of seconds.

[0111] Based on safety principles, the value is 234. That is, considering the time t2 value range is [20, 24], namely the total time range for passing through four approximate electric fields is [20, 24]. From a safety perspective, the value is 24. That is, the time for passing through the first approximate electric field is: 24 × (length of the first approximate electric field / length of the entire electrostatic precipitator) = 24 × 7 / 26 = 6.5 (seconds). That is, it can be determined that the time when the explosive flue gas leaves the first approximate electric field is 234 + 6.5 = 240.5 seconds. Therefore, starting from when the explosive flue gas is detected at the front-end detection point, at the 240.5-second moment, the first electric field is boosted back to the original voltage for effective dust removal.

[0112] And so on, obtain the voltage reduction and voltage boost moments for the second to fourth electric fields.

[0113] For the late stage of smelting, a plan to delay gas recovery after raising the lance.

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

[0115] In the late stage of smelting, approaching the moment of raising the lance, the gas detection system detects characteristic flue gas, that is, the flue gas concentration is 2%. Record the time from lowering the lance to the discovery of the characteristic flue gas as 610 seconds, and the system issues a lance raising signal. Record the time from lowering the lance to the moment of raising the lance as 700 seconds.

[0116] Starting from the discovery of the characteristic flue gas, conduct data tracking. 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 retrieval conditions set in the database, conduct retrieval and comparison in the database to obtain a set of time values from the front-end detection point to the valve detection point. After tracking 40 levels and through conversion, it is found that the time value set from lowering the lance to the moment from the front-end detection point to the valve detection point is [740, 744]. Terminate the retrieval. Based on safety principles, the initial delay time is 740 seconds - 700 seconds = 40 seconds. The time required for the valve to complete the switching action is 4 seconds. Take the safety guarantee time as 6 seconds. Therefore, starting from the moment of raising the lance, 40 - 4 - 6 = 30 (seconds). That is, after the lance raising signal appears, delay 30 seconds to start switching the valve to switch the flue gas from the recovered gas end to the chimney discharge end.

[0117] Embodiment 2

[0118] As Figure 2 shown, a converter flue gas safety control and gas recovery optimization system includes a historical data collection module, a flow model construction module, and a flow duration estimation module; among them, each module is connected electrically.

[0119] The historical data collection module pre-collects the flue gas circulation historical data of N historical flue gas flow processes, saves the flue gas circulation historical data to the retrieval database; N is the number of selected flue gas circulation tests, and sends the retrieval database to the circulation model construction module;

[0120] The circulation model construction module sets data retrieval conditions for the retrieval database and performs data optimization to construct a flue gas circulation model, and sends the flue gas circulation model to the circulation duration estimation module;

[0121] The circulation duration estimation module, during the actual smelting process, collects actual flue gas data in real time; based on the actual flue gas data and the flue gas circulation model, evaluates and predicts the expected circulation duration of the flue gas reaching the specified end point in real time, and performs safety control and gas recovery based on the expected circulation duration.

[0122] The above preset parameters or preset thresholds are all set by those skilled in the art according to the actual situation or obtained through a large number of data simulations.

[0123] The above embodiments are only used to illustrate the technical method of the present invention and not to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical method of the present invention can be modified or equivalently replaced 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 the actual smoke data and the smoke flow model, the expected flow time for the smoke to reach the specified end point is evaluated, and safety control and gas recovery are performed based on the expected flow time. The collection method of the smoke flow historical data 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.

2. A converter flue gas safety control and gas recovery optimization method according to claim 1, 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.

3. A converter flue gas safety control and gas recovery optimization method according to claim 2, characterized in that: The method of performing 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.

4. A converter flue gas safety control and gas recovery optimization method according to claim 3, 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.

5. A converter flue gas safety control and gas recovery optimization method according to claim 4, 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.

6. A converter flue gas safety control and gas recovery optimization method according to claim 5, characterized in that: Place Based on the actual smoke data and the smoke circulation model, the method for evaluating the expected circulation time for smoke to reach the specified end point 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.

7. 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 6, 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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