Energy-saving optimization control method based on sinter ignition device oxygen-enriched combustion

Abstract

The present application relates to the technical field of oxygen-enriched combustion optimization, and particularly relates to an energy-saving optimization control method based on sintering igniter oxygen-enriched combustion. The present application calculates the distribution standard deviation of the material surface temperature based on the material surface temperature field image to represent the combustion uniformity, and analyzes the temperature gradient along the material flow direction to obtain the combustion front thickness, so that the real-time quantification of the combustion uniformity and the combustion front thickness in the sintering ignition process is realized. The present application only triggers the oxygen flow adjustment when the distribution standard deviation and the combustion front thickness fall into the reference distribution interval and the reference thickness interval determined based on the historical data respectively, so that the oxygen-enriched mixing ratio can adapt to the working condition fluctuation caused by the changes of raw material composition, machine speed and material layer thickness, and the local under-burning or over-burning caused by insufficient or excessive oxygen enrichment is reduced.

Description

Technical Field

[0001] This invention relates to the field of oxygen-enriched combustion optimization technology, specifically to an energy-saving optimization control method based on oxygen-enriched combustion of a sintering igniter. Background Technology

[0002] In the sintering production of iron and steel metallurgy, the igniter ignites the material surface on the sintering machine trolley by mixing combustion gas with air. To reduce gas consumption and enhance combustion, an oxygen-enriched combustion method, in which oxygen is mixed into the combustion air, is often used.

[0003] In the prior art, such as Chinese invention patent with publication number CN112857030B, a method and device for oxygen supply through oxygen-enriched combustion in a cement rotary kiln are disclosed. This method couples membrane separation oxygen generation technology to the factory's compressed air system, utilizes by-product nitrogen-enriched gas for reuse, and supplements it with a compensation circuit to achieve low-energy on-site oxygen supply.

[0004] Another Chinese invention patent application with publication number CN118009702A discloses an oxygen-enriched combustion method in the production process of cement rotary kiln clinker, which enhances combustion by preheating oxygen-enriched air and distributing it to different parts of the kiln.

[0005] However, the aforementioned existing technologies mainly focus on optimizing the energy efficiency of the oxygen supply system itself or improving combustion efficiency through preheating, without solving the adaptive control problem of oxygen-enriched combustion during the sintering ignition process. Specifically, this manifests in the following ways: 1. The lack of real-time monitoring and quantification of the combustion uniformity and combustion depth of the sintering material surface makes it difficult to match the oxygen blending ratio with the dynamic changes in operating conditions such as raw material composition, machine speed, and material thickness. Fixed strategies are prone to local over-burning or under-burning, which in turn affects the quality of sintered ore and increases gas consumption per unit; 2. The control does not take into account the transverse temperature distribution and the thickness of the longitudinal combustion front, making it difficult to achieve synchronous optimization of combustion quality and reaction process. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and solve the problems that the lack of real-time monitoring and quantification of the combustion uniformity and combustion depth of the sintering material surface makes it difficult to dynamically match the oxygen blending ratio with changing working conditions, and that the lack of coordinated consideration of the transverse temperature distribution and the thickness of the longitudinal combustion front.

[0007] The technical solution adopted by the present invention to solve its technical problem is: an energy-saving optimization control method based on oxygen-enriched combustion of sintering igniter, including the following steps: based on the temperature field image of the sintering ignition material surface, calculate the standard deviation of the material surface temperature distribution, and analyze the temperature gradient along the material flow direction to obtain the thickness of the combustion front.

[0008] When the standard deviation of the distribution and the thickness of the combustion front both fall within the baseline distribution range and baseline thickness range determined based on historical data, the instantaneous consumption rate of ore gas per ton is calculated based on the sintering machine operating speed and the combustion gas flow rate.

[0009] When the consumption rate is higher than the baseline value determined based on historical data for three consecutive sampling periods, the initial adjustment range of oxygen flow rate is determined based on the distribution deviation of the standard deviation of the distribution relative to the center value of the baseline distribution interval.

[0010] Based on the sign relationship between the thickness deviation and distribution deviation of the combustion front thickness relative to the center value of the reference thickness range, the center value of the initial adjustment range is adjusted in the same or opposite direction to determine the final adjustment range.

[0011] Within the final adjustment range, the target oxygen flow rate adjustment is calculated with the goal of reducing the consumption rate; based on the target oxygen flow rate adjustment, the oxygen flow rate mixed into the combustion air is adjusted.

[0012] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention calculates the distribution standard deviation of the material surface temperature based on the material surface temperature field image to characterize the combustion uniformity, and analyzes the temperature gradient along the material flow direction to obtain the thickness of the combustion front, thereby realizing the real-time quantification of the combustion uniformity and the thickness of the combustion front during the sintering ignition process.

[0013] 2. This invention triggers oxygen flow adjustment only when the standard deviation of the distribution and the thickness of the combustion front fall into the benchmark distribution range and benchmark thickness range determined based on historical data, respectively. This allows the oxygen-enriched blending ratio to adapt to the fluctuations in operating conditions caused by changes in raw material composition, machine speed, and material layer thickness, thereby reducing local underburning or overburning caused by insufficient or excessive oxygen enrichment, reducing gas consumption per unit, and improving the quality of sintered ore.

[0014] 3. The present invention first determines the initial adjustment range of oxygen flow rate based on the distribution deviation of the standard deviation of the distribution relative to the center value of the reference distribution interval. Based on the positive and negative relationship between the thickness deviation of the combustion front thickness relative to the center value of the reference thickness interval and the distribution deviation, the center value of the initial adjustment range is adjusted in the same or opposite direction to determine the final adjustment range. In this way, the coupling effect of the transverse temperature distribution and the longitudinal combustion front thickness is reflected in the regulation, so as to achieve synchronous optimization of combustion quality and reaction process. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the control method of the present invention.

[0017] Figure 2 This is a schematic diagram of the process for obtaining the thickness of the combustion front in this invention.

[0018] Figure 3 This is a flowchart illustrating the process of determining the initial adjustment range for this invention.

[0019] Figure 4 This is a flowchart illustrating the process of determining the final adjustment range for this invention. Detailed Implementation

[0020] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. Furthermore, it should be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale.

[0021] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification.

[0022] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0024] The following description, in conjunction with the accompanying drawings, details a specific scheme for an energy-saving optimization control method based on oxygen-enriched combustion of a sintering igniter provided by this invention.

[0025] Please see Figure 1 The flowchart shows an energy-saving optimization control method based on oxygen-enriched combustion of a sintering igniter provided by the present invention, which specifically includes the following steps: Step S1, first generate a temperature field image of the sintering ignition material surface, and then obtain the standard deviation of the material surface temperature distribution and the thickness of the combustion front.

[0026] The sintering ignition surface mentioned here refers to the combustion reaction surface area formed after the mixture carried on the sintering machine trolley is ignited below the igniter. Its width is equal to the width of the sintering machine trolley, and its length extends along the material flow direction.

[0027] Step S10: Generate a temperature field image. Specifically, a multi-spectral infrared imager array arranged above and to the side of the sintering ignition device can be used to simultaneously acquire multi-band spontaneous emission signals from the combustion area of ​​the sintering ignition material surface, generating an original sequence of radiation intensity images.

[0028] Next, the single frame image with the highest signal-to-noise ratio is selected from the radiation intensity image sequence, and spatial domain filtering, such as Gaussian low-pass filtering, is applied to it. This image is then spatially decomposed into a first component representing the basic heating background and a second component reflecting the transient combustion front.

[0029] The basic heating background refers to the uniform thermal radiation field covering the entire width of the material surface formed by the stable heating of the igniter flame. The leading-edge transient combustion refers to the dynamic temperature change process caused by the exothermic combustion reaction of the mixture itself.

[0030] Then, a spatiotemporal coupling analysis is performed on the second component. Specifically, a three-dimensional data cube is constructed with the time series as the third dimension, and a sliding time window is set along the material flow direction; the slope of the temperature change at each location point in the three-dimensional data cube within the sliding time window is calculated.

[0031] The length of the sliding time window can be taken as 1.5 to 2 times the time the material surface stays in the ignition zone, for example, 1.7 times.

[0032] If a location is directly heated directly below the igniter, and the slope of its temperature change decreases by more than twice the median of the temperature decrease at all locations within the sliding time window, it is determined to be an area dominated by external heating.

[0033] If the temperature at a certain location only begins to rise after it is removed from the heating zone directly below the igniter, and the slope of the temperature change remains greater than zero for at least 5 sampling cycles, then it is determined to be a region dominated by the exothermic reaction of the material itself.

[0034] If neither of the above two conditions is met at a certain location, it is considered a vague area that cannot be clearly distinguished. Based on this, the area dominated by external heating and the area dominated by the exothermic reaction of the material itself are separated, eliminating interference caused by external ignition flame fluctuations.

[0035] Subsequently, the signals from the external heating-dominated region and the material's own reaction heat-dominated region are superimposed with the first component at the pixel level using weighted summaries.

[0036] Specifically, pixels within the region dominated by the material's own exothermic reaction are assigned a higher weight (e.g., 0.7) and a lower weight (e.g., 0.3) to the first component; pixels within the region dominated by external heating and the first component are assigned weights using the opposite logic. Pixels in the blurred region are assigned a weight of 0.5 each, along with the first component.

[0037] If the current combustion front advances at a relatively high speed, such as greater than 2.5 m / min, the weight of the first component of the material's own reaction exothermic region can be appropriately reduced to 0.2 so that the subsequent temperature field image can accurately reflect the rapidly changing material's own reaction exothermic region.

[0038] Finally, based on the approximate form of Planck's blackbody radiation law, the monochromatic radiation thermometry formula is used to convert the radiation intensity of the fused signal into a temperature distribution, resulting in a two-dimensional temperature distribution matrix, i.e., a temperature field image.

[0039] The specific form of the monochromatic radiation thermometry formula is as follows: .

[0040] Where T is temperature (in K); λ is the working center wavelength of the multispectral infrared imager (m); and L is the spectral radiance at the center wavelength λ measured by the multispectral infrared imager (W·m). · · ), Corresponding to the launch area, Corresponding to wavelength interval; and These are the first and second radiation constants, both of which are universal physical constants. Specifically, =1.1910× (W· · ), =1.4388× (m·K).

[0041] Step S11: Calculate the standard deviation of the material surface temperature distribution. Specifically, in the two-dimensional coordinate system of the temperature field image, select a cross section perpendicular to the material flow direction and spanning the entire width of the material surface. Use 1 / 100 of the width of the sintering machine trolley as the sampling interval to perform equidistant temperature sampling along the cross section. The number of sampling points is odd, thereby obtaining the temperature sequence.

[0042] The sampling interval can be adjusted appropriately according to the width of the sintering machine trolley, which is an inherent parameter of the equipment. For example, when the trolley width exceeds 3.5 meters, it can be reduced to 1 / 120, and when it is less than 2 meters, it can be increased to 1 / 80, in order to balance resolution and computational load.

[0043] Next, the temperature difference between adjacent sampling points is calculated point by point from left to right in the temperature sequence to obtain the left-side temperature gradient sequence. Similarly, the right-side temperature gradient sequence is obtained from right to left.

[0044] Considering that the temperature typically rises as it transitions from the sidewall of the trolley to the central region, the search proceeds from the starting position on the left to the right in the left-hand temperature gradient sequence. The point where three consecutive positive gradient values ​​first appear is identified as the first boundary point.

[0045] Meanwhile, in the rightward temperature gradient sequence, starting from the right-hand starting position and searching to the left, the starting point where three consecutive positive gradient values ​​first appear is determined as the second boundary point.

[0046] If no suitable starting point is found in either the left-hand or right-hand temperature gradient sequence, the current sampling is deemed invalid, the subsequent calculations for the current sampling period are terminated, the existing control parameters are maintained, and the process restarts in the next sampling period.

[0047] The first and second boundary points, as determined above, are located in the middle of the temperature sequence and are symmetrical to each other. The section between the first and second boundary points is designated as the central sampling section. This eliminates abnormal temperature interference in the edge areas on both sides of the trolley, which is often caused by heat dissipation from the furnace wall, uneven material distribution, or flame deflection.

[0048] If the dust concentration at the sintering site is high and the image signal-to-noise ratio is low, the threshold can be increased to five consecutive positive gradient values ​​for the first time. If the image is clear and the signal-to-noise ratio is high, the threshold can be reduced to two consecutive positive gradient values ​​to accelerate boundary recognition.

[0049] Then, in order to eliminate abnormally high temperature points caused by local hot spots or measurement noise, for sampling points in the middle sampling section whose temperature is higher than that of the adjacent sampling points on the left and right, their temperature is replaced with the arithmetic mean of the temperatures of the adjacent sampling points on the left and right.

[0050] Subsequently, a sliding window of length 3 is used to perform mean filtering on the replaced temperature sequence. For each temperature point except the first and last points, the average temperature value of that point and its two adjacent sampling points is used instead. After traversing the entire replaced temperature sequence, a smoothed temperature sequence is obtained.

[0051] Finally, the standard deviation of the smoothed temperature series is calculated as the standard deviation of the material surface temperature distribution. It should be noted that if the length of the temperature series after replacement is less than 5, mean filtering is not performed to avoid over-smoothing leading to insufficient effective data.

[0052] Please see Figure 2 Step S12: Analyze the temperature gradient along the material flow direction to obtain the thickness of the combustion front.

[0053] The specific process is as follows: On the temperature field image, within the width range corresponding to the central sampling segment, at least five longitudinal sampling lines are selected at equal intervals along the direction perpendicular to the material flow, with a sampling interval of 1 / 20 of the width of the central sampling segment. The complete temperature change process from low temperature to high temperature and then to cooling can be captured along these longitudinal sampling lines, thereby accurately locating the combustion front.

[0054] Then, along the material flow direction, the temperature difference between adjacent sampling points on each longitudinal sampling line is divided by the distance between them along the material flow direction to obtain the temperature change rate, which in turn forms the corresponding longitudinal temperature gradient sequence.

[0055] Next, in each longitudinal temperature gradient sequence, the first transition point where the gradient value changes from positive to non-positive is determined, and the position of the first transition point in the material flow direction is marked as the combustion front position of the corresponding longitudinal sampling line.

[0056] If no first transition point meeting the conditions is found in a certain longitudinal temperature gradient sequence, then the longitudinal temperature gradient sequence is discarded and will not be included in the subsequent calculation of the combustion front thickness.

[0057] Finally, all combustion front positions are projected onto the same material flow direction coordinate axis, and the difference between the maximum and minimum values ​​is taken as the combustion front thickness, which characterizes the longitudinal extension range of the combustion reaction zone.

[0058] If the width of the central sampling segment is large (e.g., exceeding 2 meters), the number of sampling lines can be increased to 8 to improve the spatial resolution of the combustion front location. If the width of the central sampling segment is small (e.g., less than 1.5 meters), the number of sampling lines can be reduced to 4 to reduce the computational load.

[0059] Step S2: Determine the current ignition and combustion state based on the standard deviation of the distribution and the thickness of the combustion front; calculate the instantaneous consumption rate of coal gas per ton of ore to determine the coal gas consumption state.

[0060] First, the standard deviation of the distribution and the thickness of the combustion front are compared with the baseline distribution range and the baseline thickness range determined based on historical data.

[0061] The process for determining the baseline distribution interval and baseline thickness interval is as follows: During the period when the sinter quality indicators (such as drum strength and FeO content) meet the production process requirements, at least 100 sets of distribution standard deviation and combustion front thickness data are continuously collected; after removing outliers, the average value μ and standard deviation σ are calculated. The baseline distribution interval and baseline thickness interval are determined according to [μ-k×σ, μ+k×σ].

[0062] Where k is the confidence coefficient, and in this invention, k=2, corresponding to approximately 95% confidence level. If the raw materials in the production process change frequently, the value of k can be appropriately reduced; if a highly stable control benchmark is required, the value of k can be increased.

[0063] If the standard deviation of the distribution does not fall within the baseline distribution range, or the thickness of the combustion front does not fall within the baseline thickness range, or neither falls within the corresponding range, it indicates that the current combustion state is unstable. In this case, no further oxygen flow rate adjustment will be made; the current oxygen flow rate will be maintained, and an abnormal combustion state alarm will be triggered, prompting manual intervention.

[0064] If the standard deviation of the distribution falls within the baseline distribution range and the thickness of the combustion front falls within the baseline thickness range, it indicates that the current ignition and combustion state is relatively stable.

[0065] At this point, the instantaneous consumption rate of ore gas per ton is calculated. Specifically, the instantaneous operating speed values ​​of multiple sintering machines are acquired at fixed time intervals within the current sampling period via the sintering machine's main drive encoder.

[0066] Simultaneously, a thermal mass flow meter installed on the gas pipeline acquires multiple instantaneous values ​​of the combustion gas flow rate collected at the same fixed time interval within the current sampling period. The fixed time interval can be exemplarily set to 1 second.

[0067] Then, the arithmetic mean of the instantaneous operating speed of all sintering machines and the instantaneous flow rate of all combustion gas is calculated separately, and used as the representative value of operating speed and gas consumption for the current sampling period.

[0068] Next, the sintering ore throughput is obtained by multiplying the representative value of the operating speed, the width of the sintering machine trolley, the thickness of the sintering bed determined by the existing material distribution system, and the average bulk density of the sintering mixture. The thickness of the sintering bed remains constant during the sintering process.

[0069] Subsequently, the representative value of gas consumption is divided by the sintering ore processing volume to obtain the instantaneous gas consumption rate per ton of ore in the current sampling period.

[0070] The average bulk density is determined based on historical data. When the raw material ratio remains unchanged, the average of the measured loose bulk density values ​​of multiple batches (at least 10 batches) of the mixture is used as the average bulk density; when the raw material ratio changes, the average of the measured loose bulk density values ​​of at least 5 batches of the mixture under the new ratio is used as the average bulk density.

[0071] Furthermore, in order to determine whether gas consumption remains excessively high, the consumption rate is compared with a baseline value determined based on historical data.

[0072] The process for determining the benchmark value is as follows: During periods when the sinter quality indicators meet the requirements of the production process, multiple sets of consumption rate data are collected. To avoid the benchmark value being too low due to a few extremely low values, the difference between the upper quartile and one standard deviation of the consumption rate, and the difference between its arithmetic mean and one standard deviation are calculated, and the larger of the two values ​​is taken as the benchmark value.

[0073] When the consumption rate is higher than the benchmark value for three consecutive sampling periods, it indicates that the gas consumption efficiency is consistently high, and gas consumption needs to be reduced by optimizing oxygen-enriched combustion. In this case, the initial adjustment range of the oxygen flow rate is determined based on the distribution deviation of the standard deviation relative to the center value of the benchmark distribution interval. Otherwise, the current oxygen flow rate is maintained unchanged.

[0074] If the current operating condition lags behind the adjustment response, such as historical data showing that the adjustment action takes more than 3 sampling periods to take effect, the number of consecutive sampling periods can be increased to 5 to avoid misjudgment.

[0075] Please see Figure 3 and Figure 4 Step S3: First determine the initial adjustment range, then determine the final adjustment range.

[0076] The initial adjustment range determination process is as follows: calculate the difference between the standard deviation of the distribution and the center value of the benchmark distribution interval, and use it as the distribution deviation.

[0077] If the distribution deviation is greater than zero, it indicates that incomplete combustion and uneven temperature distribution may be caused by local oxygen deficiency. In this case, the adjustment direction should be to increase the oxygen flow rate.

[0078] If the distribution deviation is less than zero, it means that although the temperature distribution is uniform, there may be a risk of overheating. In this case, the adjustment direction should be to reduce the oxygen flow rate to avoid continued oxygen enrichment, which would lead to increased gas consumption.

[0079] If the distribution deviation is zero, it indicates that the temperature distribution uniformity is in an ideal state. At this time, the adjustment direction is determined to maintain the current oxygen flow rate.

[0080] After determining the adjustment direction, the distribution deviation is divided by the width of the baseline distribution interval to obtain the distribution normalization coefficient, which is then multiplied by the current oxygen flow rate baseline value to obtain the adjustment value. The current oxygen flow rate baseline value refers to the target blending flow rate at the end of the previous sampling period.

[0081] If the control method of the present invention is first applied or the sintering production process is restarted after a long shutdown, the arithmetic mean of the historical oxygen flow data can be calculated based on the period within the last 3 months when the sinter quality indicators meet the production process requirements, and then multiplied by the distribution normalization coefficient to obtain the adjustment value.

[0082] Then, when the adjustment direction is to increase the oxygen flow rate, the current oxygen flow rate baseline value is added to the adjustment value to obtain the preliminary adjustment center value of the oxygen flow rate.

[0083] When adjusting the direction to reduce oxygen flow, the current oxygen flow baseline value is subtracted from the adjustment value to obtain the initial adjustment center value of oxygen flow.

[0084] Next, the ratio of the baseline distribution interval width to the current oxygen flow rate baseline value is multiplied by a preset amplitude coefficient to obtain the adjustment margin. Using the initial adjustment center value as a baseline, upper and lower offset margins are obtained, thus forming the initial adjustment range for the oxygen flow rate.

[0085] In this invention, the preset amplitude coefficient mentioned above is exemplarily set to 0.1. If the difference between the current combustion front thickness and the upper limit of the reference thickness range is less than 10% of the width of the reference thickness range, the amplitude coefficient can be reduced to 0.05 to avoid over-adjustment; while if the difference is greater than 30% of the width of the reference thickness range, the amplitude coefficient can be increased to 0.15 to accelerate the adjustment convergence speed.

[0086] However, if the temperature is uniform but the combustion front is too thick, excessive oxygen may cause the combustion reaction zone to lengthen longitudinally. In this case, further oxygenation may actually cause the combustion reaction zone to lengthen further longitudinally. Therefore, the final adjustment range needs to be determined by considering the thickness of the combustion front, which reflects the longitudinal combustion depth.

[0087] The final adjustment range determination process is as follows: Calculate the difference between the current combustion front thickness and the center value of the reference thickness interval, which is taken as the thickness deviation. Divide the thickness deviation by the width of the reference thickness interval to obtain the thickness normalization coefficient, and then multiply the thickness normalization coefficient by the center value of the initial adjustment range to obtain the correction value.

[0088] Next, determine the sign relationship between the thickness deviation and the distribution deviation: if the signs are the same, it is determined to be a same-direction adjustment, and the center value of the initial adjustment range is added to the correction value. If the signs are different, it is determined to be a reverse adjustment, and the center value of the initial adjustment range is subtracted from the correction value.

[0089] Finally, keeping the adjustment margin used to generate the initial adjustment range unchanged, the upper and lower limits are reconstructed based on the final adjustment center value, thereby obtaining the final adjustment range of oxygen flow.

[0090] Step S4: Calculate the target oxygen flow rate adjustment based on the final adjustment range.

[0091] The specific process is as follows: calculate the difference between the consumption rate of the current sampling period and the previous adjacent sampling period, and use it as the change in consumption rate.

[0092] When the standard deviation of the distribution is greater than the center value of the baseline distribution interval, it indicates poor temperature uniformity, requiring increased oxygen to improve combustion completeness. Therefore, the basic adjustment direction for oxygen flow rate is determined to be increasing the oxygen flow rate, and the upper limit of the final adjustment range is taken as the target oxygen flow rate adjustment amount.

[0093] When the standard deviation of the distribution is less than or equal to the center value of the baseline distribution interval, further judgment is made based on the thickness of the combustion front.

[0094] The judgment logic is as follows: 1) If the thickness of the combustion front is less than the center value of the reference thickness interval, it indicates that the combustion state is uniform and concentrated, and oxygen can be reduced. Therefore, the basic adjustment direction of oxygen flow is determined to be to reduce oxygen flow, and the lower limit of the final adjustment range is taken as the target oxygen flow adjustment amount.

[0095] 2) If the thickness of the combustion front is greater than or equal to the center value of the reference thickness range, it indicates that although the combustion is uniform, the combustion reaction zone has been elongated. Increasing oxygen may exacerbate overburning, while reducing oxygen may affect uniformity. Therefore, the basic adjustment direction of oxygen flow rate is determined to maintain the current oxygen flow rate, and the target oxygen flow rate adjustment is set to zero.

[0096] Furthermore, the immediate effects of the adjustment also need to be considered, and the judgment should be based on the change in the consumption rate.

[0097] The judgment logic is as follows: 1) If the change in consumption rate is less than zero and the basic adjustment direction is to increase oxygen flow, it indicates that although the current basic adjustment direction is to increase oxygen, the actual gas consumption rate has already begun to decrease based on the previous sampling period. In this case, to avoid over-adjustment, the target oxygen flow adjustment amount is set to zero, and no adjustment is made for the time being.

[0098] 2) If the change in consumption rate is less than zero and the basic adjustment direction is to reduce oxygen flow, then maintain the target oxygen flow adjustment corresponding to that basic adjustment direction.

[0099] 3) If the change in consumption rate is greater than zero and the basic adjustment direction is to increase oxygen flow, it indicates that the oxygenation operation has not yet taken effect or there are other interferences. In this case, the target oxygen flow adjustment corresponding to the basic adjustment direction should be maintained.

[0100] 4) If the change in consumption rate is greater than zero, and the basic adjustment direction is to reduce oxygen flow or maintain the current oxygen flow, then for the sake of conservative control, no oxygen reduction or increase operation will be performed, and the target oxygen flow adjustment will be set to zero.

[0101] Furthermore, to prevent excessive control disturbances, a limit is imposed on the magnitude of the target oxygen flow rate adjustment.

[0102] Specifically, the maximum allowable adjustment range is calculated as 20% of the current oxygen flow rate baseline. If the absolute value of the target oxygen flow rate adjustment is greater than the maximum adjustment range, it is corrected to the maximum adjustment range while retaining the original positive or negative sign; otherwise, the target oxygen flow rate adjustment remains unchanged.

[0103] Step S5: Adjust the oxygen flow rate mixed into the combustion air according to the target oxygen flow rate adjustment amount.

[0104] Specifically, the total air flow rate before entering the igniter combustion chamber can be obtained by a thermal mass flow meter installed on the combustion air main, which serves as the mainstream air flow rate in the combustion air duct.

[0105] Simultaneously, the nominal oxygen concentration output from oxygen-enriched gas cylinders or oxygen generators is also obtained as the fixed oxygen volume concentration for blending the oxygen-enriched gas. The fixed oxygen volume concentration is considered constant within a single sampling period, with a typical value of 90%–95%.

[0106] Then, based on the target oxygen flow rate adjustment, the mainstream air flow rate, and the fixed oxygen volume concentration, the target mixing flow rate of the oxygen-enriched gas is calculated.

[0107] The specific calculation formula is as follows: .

[0108] in, The target mixing flow rate of oxygen-enriched gas (Nm³ / h, i.e., standard cubic meters per hour). Adjustment amount for target oxygen flow rate (Nm³ / h); To maintain a fixed oxygen volume concentration, such as 0.93; The mainstream airflow rate is usually taken as an approximate volume fraction of oxygen in the air, which is 0.21.

[0109] Next, the target mixing flow rate is used as the setpoint for the oxygen-enriched gas flow control loop.

[0110] The proportional-integral controller generates a regulating valve opening command based on the deviation between a given value and the actual flow rate monitored in real time by an oxygen-enriched pipeline flow meter. This command is then output to the regulating valve on the oxygen-enriched gas pipeline, driving the valve to operate. The specific process for generating the regulating valve opening command is existing technology and will not be elaborated here.

[0111] In a preferred embodiment of the present invention, to ensure safety, a pressure sensor and a flow limit alarm device can be installed on the oxygen-enriched gas pipeline. The pipeline pressure and instantaneous flow rate are monitored in real time during the adjustment process.

[0112] If the monitored values ​​of pipeline pressure or instantaneous flow exceed their respective safety thresholds, the current regulation command will be immediately interrupted, and the regulating valve will be switched to a safe opening degree first. If the switching is blocked, it will be locked in the current position. At the same time, an audible and visual alarm will be triggered. Automatic control can only be resumed after manual confirmation that the pipeline pressure and instantaneous flow have returned to below the safety threshold and there are no abnormalities such as leakage or blockage.

[0113] The safety threshold for pipeline pressure can be taken as 80% of the pipeline design pressure, and the safety threshold for instantaneous flow rate can be taken as 90% of the maximum output capacity of the oxygen-enriched source. The pipeline design pressure is obtained from the pipeline design drawings or technical specifications. The maximum output capacity of the oxygen-enriched source is provided by the nameplate parameters of the oxygen-enriched equipment or the factory test report.

[0114] The safe opening degree can be taken as 10% to 15% of the valve's full stroke to ensure that a minimum oxygen supply is maintained even if the current regulation command is interrupted, while avoiding safety hazards caused by excessive oxygen.

[0115] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented in software, the above embodiments can be implemented, in whole or in part, as a computer program product.

[0116] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0117] In addition, the functional modules in the various embodiments of the present invention can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0118] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0119] Finally, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An energy-saving optimization control method based on sinter ignition device oxygen-enriched combustion, characterized in that, Includes the following steps: Based on the temperature field image of the sintering ignition material surface, the standard deviation of the material surface temperature distribution is calculated, and the thickness of the combustion front is obtained by analyzing the temperature gradient along the material flow direction. When the standard deviation of the distribution and the thickness of the combustion front both fall within the baseline distribution range and the baseline thickness range determined based on historical data, the instantaneous consumption rate of ton ore gas is calculated based on the sintering machine operating speed and the combustion gas flow rate. When the consumption rate is higher than the baseline value determined based on historical data for three consecutive sampling periods, the initial adjustment range of oxygen flow rate is determined based on the distribution deviation of the standard deviation of the distribution relative to the center value of the baseline distribution interval. Based on the sign relationship between the thickness deviation and distribution deviation of the combustion front thickness relative to the center value of the reference thickness range, the center value of the initial adjustment range is adjusted in the same or opposite direction to determine the final adjustment range. Within the final adjustment range, the target oxygen flow rate adjustment is calculated with the goal of reducing the consumption rate; Adjust the flow rate of oxygen mixed into the combustion air according to the target oxygen flow rate adjustment amount; The process of generating the temperature field image is as follows: Simultaneously acquire multi-band spontaneous emission signals from the combustion zone of the sintering material surface, and decompose them in the spatial domain into a first component characterizing the basic heating background and a second component reflecting the transient combustion at the forefront. A spatiotemporal coupling analysis was performed on the second component to separate the region dominated by external heating and the region dominated by the exothermic reaction of the material itself. The separation result is fused with the first component, and the fused signal is converted from radiation intensity to temperature distribution to generate a temperature field image. The calculation process for the standard deviation of the distribution is as follows: On the temperature field image, temperature sequences covering the width of the material surface are obtained by sampling at equal intervals along the transverse section perpendicular to the material flow direction. The first boundary point and the second boundary point are determined from the temperature sequence. The first boundary point and the second boundary point are located in the middle of the temperature sequence and are symmetrical to each other. The segment between the two is taken as the middle sampling segment. For sampling points in the middle sampling section whose temperature is higher than that of their left and right adjacent sampling points, their temperature is replaced with the arithmetic mean of the temperatures of their left and right adjacent sampling points. The temperature sequence after replacement is subjected to mean filtering to obtain a smooth temperature sequence; Calculate the standard deviation of the smoothed temperature series as the standard deviation of the material surface temperature distribution.

2. The energy-saving optimization control method for oxygen-enriched combustion based on a sintering igniter according to claim 1, characterized in that, The process of determining the first and second boundary points is as follows: The temperature difference between adjacent sampling points is calculated point by point from left to right in the temperature sequence to obtain the left-side temperature gradient sequence. Similarly, the right-side temperature gradient sequence is calculated. In the left-hand temperature gradient sequence, starting from the left-hand starting position and searching to the right, the starting point where multiple consecutive positive gradient values ​​first appear is determined as the first boundary point. In the rightward temperature gradient sequence, starting from the right-hand starting position and searching to the left, the starting point where multiple consecutive positive gradient values ​​first appear is determined as the second boundary point.

3. The energy-saving optimization control method based on oxygen-enriched combustion of a sintering igniter according to claim 1, characterized in that, The process of obtaining the thickness of the combustion front is as follows: On the temperature field image, within the width range corresponding to the middle sampling segment, multiple longitudinal sampling lines are selected at equal intervals along the direction perpendicular to the material flow; Along the material flow direction, the rate of temperature change between adjacent sampling points on the longitudinal sampling line is calculated to obtain the longitudinal temperature gradient sequence; In each longitudinal temperature gradient sequence, the first transition point where the gradient value changes from positive to non-positive is determined, and its position in the material flow direction is marked as the combustion front position of the corresponding longitudinal sampling line. Calculate the difference between the maximum and minimum values ​​at all combustion front locations, and use the difference as the combustion front thickness.

4. The energy-saving optimization control method based on oxygen-enriched combustion of a sintering igniter according to claim 1, characterized in that, The consumption rate is calculated as follows: Acquire the instantaneous values ​​of multiple sintering machine operating speeds and multiple instantaneous values ​​of combustion gas flow rates collected at fixed time intervals within the current sampling period; Calculate the arithmetic mean of the instantaneous operating speeds of all sintering machines, and use it as the representative value of the operating speed; The sintering ore processing capacity is obtained by multiplying the representative value of the operating speed, the width of the sintering machine trolley, the thickness of the sintering material layer set by the material feeding system, and the average bulk density of the sintering mixture determined based on historical data. Calculate the arithmetic mean of all instantaneous values ​​of combustion gas flow rate as a representative value of gas consumption; Divide the representative value of coal gas consumption by the amount of sintered ore processed to obtain the instantaneous coal gas consumption rate per ton of ore in the current sampling period.

5. The energy-saving optimization control method based on oxygen-enriched combustion of a sintering igniter according to claim 1, characterized in that, The process of determining the initial adjustment scope is as follows: Calculate the difference between the standard deviation of the distribution and the center value of the reference distribution interval, and use it as the distribution deviation; When the distribution deviation is greater than zero, the adjustment direction is determined to be to increase the oxygen flow rate; when the distribution deviation is less than zero, the adjustment direction is determined to be to decrease the oxygen flow rate. Divide the distribution deviation by the width of the baseline distribution interval to obtain the distribution normalization coefficient, and multiply it by the current oxygen flow baseline value to obtain the adjustment value; Based on the adjustment direction, the current oxygen flow rate baseline value is superimposed with the adjustment value to obtain the preliminary adjustment center value of oxygen flow rate; The adjustment margin is obtained by multiplying the ratio of the baseline distribution interval width to the current oxygen flow baseline value by a preset amplitude coefficient. Based on the initial adjustment center value, the adjustment margins are shifted upwards and downwards respectively to obtain the upper and lower limits of the initial adjustment, thus forming the initial adjustment range of oxygen flow rate.

6. The energy-saving optimization control method based on oxygen-enriched combustion of a sintering igniter according to claim 5, characterized in that, The process of determining the final adjustment range is as follows: Calculate the difference between the current combustion front thickness and the center value of the reference thickness interval, and use it as the thickness deviation; Divide the thickness deviation by the width of the reference thickness range to obtain the thickness normalization coefficient, and multiply it by the center value of the initial adjustment range to obtain the correction value; When the signs of thickness deviation and distribution deviation are the same, it is determined to be an adjustment in the same direction, and the center value of the initial adjustment range is added to the correction value; When the signs of thickness deviation and distribution deviation are inconsistent, it is determined to be a reverse adjustment, and the center value of the initial adjustment range is subtracted from the correction value; Keeping the adjustment margin unchanged, the upper and lower limits are reconstructed based on the final adjustment center value, thereby obtaining the final adjustment range of oxygen flow rate.

7. The energy-saving optimization control method based on oxygen-enriched combustion of a sintering igniter according to claim 1, characterized in that, The process of calculating the target oxygen flow rate adjustment is as follows: Calculate the difference between the consumption rate of the current sampling period and the previous adjacent sampling period, and use it as the change in consumption rate. Based on the comparison between the standard deviation of the distribution and the center value of the baseline distribution interval, and the thickness of the combustion front and the center value of the baseline thickness interval, the basic adjustment direction of the oxygen flow rate is determined to be increasing the oxygen flow rate, decreasing the oxygen flow rate, or maintaining the current oxygen flow rate. Based on the established basic adjustment direction, select one from the upper limit, lower limit, and zero value of the final adjustment range as the target oxygen flow rate adjustment amount; If the change in consumption rate is less than zero and the basic adjustment direction is to increase oxygen flow, then the target oxygen flow adjustment amount is set to zero.

8. The energy-saving optimization control method based on oxygen-enriched combustion of a sintering igniter according to claim 1, characterized in that, The process of adjusting the flow rate of oxygen mixed into the combustion air is as follows: Obtain the current mainstream air flow rate in the combustion air duct, as well as the fixed oxygen volume concentration for mixing with oxygen-enriched gas; Based on the target oxygen flow rate adjustment, the mainstream air flow rate, and the fixed oxygen volume concentration, the target mixing flow rate of the oxygen-enriched gas is calculated and used as the setpoint for the oxygen-enriched gas flow control loop. Based on the deviation between the given value and the actual flow rate value monitored in real time, proportional-integral control calculations are performed to generate a regulating valve opening command and output it to the regulating valve on the oxygen-enriched gas pipeline.

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