Sintering method capable of accurately controlling sintering end point

Abstract

The invention provides a sintering method capable of accurately controlling a sintering end point, which comprises the following steps: S1, collecting temperature data of exhaust gas of each air bellow, constructing a curvilinear equation of air bellow positions and exhaust gas temperatures, and calculating an air bellow number corresponding to the sintering end point and the air bellow exhaust gas temperature of the sintering end point; s2, according to the positions of the bellows with the sintering end point calculated, three monitoring bellows are selected at the proper positions of the upstream of the bellows, and the exhaust gas temperature of the bellows is monitored in real time; and S3, according to the three monitored air bellow exhaust gas temperatures, the sintering condition is adjusted in time by monitoring the deviation between the air bellow exhaust gas temperatures and the predicted temperature, the deviation is reduced, and it is ensured that the sintering end point position and the sintering end point temperature reach the predicted range. The sintering state is reasonably judged according to the real-time parameters in the sintering process, the control parameters are effectively adjusted in time, the sintering end point position and the sintering end point temperature can be controlled within the prediction range, the phenomena of over-sintering and under-sintering are completely eradicated, and finally the purposes of guaranteeing the quality, improving the production and reducing the cost are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of ironmaking and sintering, and in particular to a sintering method capable of accurately controlling a sintering endpoint. Background Art

[0002] Sintering is an important process in preparing furnace charges for steel production. It involves uniformly mixing iron ore powder, flux, fuel and an appropriate amount of water, then igniting and burning. The combustion reaction is carried out from top to bottom under the action of the exhaust fan. During the combustion process, the high temperature causes the sintering material components to melt or soften, chemical and physical reactions occur, and a quantitative liquid phase is generated. After cooling, the components adhere to each other to form blocks, which are sintered ore and can be directly fed into the blast furnace as an ironmaking raw material.

[0003] The sintering process is a complex industrial process involving mass transfer, heat transfer and physical and chemical reactions. The sintering endpoint refers to the point where the sintering process ends. The instantaneous position where the flue gas temperature of the tail wind box of the sintering machine reaches the highest and then begins to decline is usually judged as the sintering endpoint. The sintering endpoint is an important process parameter in the sintering production process. Whether the sintering endpoint is reasonable and stable directly affects the sintering production efficiency, product quality, fuel consumption and production stability; accurate sintering endpoint control is the key to ensuring the quality of sintered ore and reducing sintering energy consumption. Generally speaking, for small and medium-sized sintering machines, the sintering endpoint is generally controlled at the position of the second to last wind box, while for large sintering machines, the sintering endpoint is generally controlled at the third to last wind box. However, since sintering production involves mass transfer, heat transfer and complex physical and chemical reactions, and is affected by various unstable factors such as equipment conditions, raw material conditions, and process conditions, the sintering endpoint is not easy to control. If the sintering endpoint is advanced, the sintered ore will be overburned, the sintering area of ​​the sintering machine cannot be effectively utilized, the output will decrease, and the utilization coefficient of the sintering machine trolley per unit area will decrease; if the sintering endpoint is delayed, the material layer will be underburned, the return rate will increase, the finished product rate will decrease, and the quality of the sintered ore will deteriorate. In addition to the position of the sintering endpoint, the temperature of the sintering endpoint also has a great influence on the agglomeration rate and agglomeration quality of the sintered ore. If the sintering endpoint temperature is not properly controlled, too high or too low will have a negative impact on the quality of the sintered ore. Too high a sintering endpoint temperature may cause the ore particle structure to change, increase the hardness of the sintered ore, reduce its quality, and increase energy consumption and production costs; while too low a sintering endpoint temperature may cause the ore particle structure to be not dense enough, further affecting the quality of the sintered ore. Therefore, the reasonable control of the sintering endpoint position and endpoint temperature is the key to improving the quality of sintered ore, reducing energy consumption and extending the service life of equipment.

[0004] At present, in conventional sintering production, there are mainly the following methods to determine the sintering endpoint:

[0005] 1. Sintering machine tail section image method: Use thermal imaging temperature measurement technology to observe the video image of the sintering machine tail in real time to understand the relevant information of the tail section; however, this method is difficult to give a real image of the tail section and cannot give the precise location of the end point;

[0006] 2. Bellows exhaust gas temperature method: This method is the most commonly used method in production. The endpoint is determined by detecting the highest point of the exhaust gas temperature discharged from the bellows. However, in production, it can only be determined by artificial experience assisted by a small amount of instrument data collection. It is highly dependent on the subjective judgment and experience of workers, which inevitably brings great blindness and constraints. It is easy to cause the endpoint to deviate from the set value, resulting in over-burning and under-burning, affecting the sintering output quality and equipment operation;

[0007] 3. The bellows negative pressure method is greatly affected by factors such as air leakage and has high costs. Relatively few companies use this method.

[0008] 4. Waste gas composition analysis method. Since the waste gas analysis equipment is relatively expensive, has a short equipment life, is greatly restricted by equipment conditions, and has high production costs, few companies use this method.

[0009] The above four methods cannot achieve precise control of the sintering process and can only roughly determine the sintering end point. However, due to the characteristics of slow response, large hysteresis, and long cycle in the sintering process, the determined end point position only describes the status of the sintering process. When the determined end point position deviates from the predetermined position, it is too late to adjust the production. Therefore, it is particularly important to predict the sintering situation in advance and make timely adjustments so that the sintering end point position reaches the preset position accurately and the sintering end point temperature is controlled within the design control range. Summary of the invention

[0010] In order to overcome the disadvantages of the prior art, the present invention provides a sintering method capable of accurately controlling the sintering endpoint.

[0011] The technical solution adopted by the present invention to solve its technical problem is:

[0012] A sintering method capable of accurately controlling the sintering endpoint comprises the following steps:

[0013] S1. Collect the temperature data of the exhaust gas from each wind box, construct the curve equation of the wind box position and the exhaust gas temperature, and calculate the wind box number X corresponding to the sintering end point. max , and the wind box exhaust gas temperature T at the end of sintering max ;

[0014] S2. According to the estimated wind box position of the sintering end point, three monitoring wind boxes are selected at appropriate positions upstream thereof to monitor the exhaust gas temperature in real time;

[0015] S3. According to the three monitoring bellows exhaust gas temperatures, by monitoring the deviation between the bellows exhaust gas temperature and the predicted temperature, the sintering condition is adjusted in time to reduce the deviation, so as to ensure that the sintering end point position and the sintering end point temperature reach the predicted range of step S1.

[0016] In step S1, the bellows position X i , wind box exhaust gas temperature T i The quadratic relationship is:

[0017] T i =AX i 2 +BX i +C

[0018] Where, X i is the bellows position;

[0019] T i is the windbox exhaust gas temperature, in °C;

[0020] i is a natural number, and its value is 1, 2, ..., n; n is the total number of bellows;

[0021] A, B, and C are all constant coefficients, and A is taken from [-43, -32], B is taken from [1212, 1421], and C is taken from [-11986, -10865].

[0022] The temperature data of the wind box exhaust gas is collected in no less than four batches.

[0023] In step S2, the wind box located at the midpoint is selected as the first monitoring wind box, the second wind box behind the first monitoring wind box is selected as the second monitoring wind box, and the fourth wind box in front of the predicted sintering end point wind box is selected as the third monitoring wind box.

[0024] The step S3 specifically includes the following steps:

[0025] S31, with 12.3% T max ~15.7%T max As the exhaust gas standard temperature of the first monitoring wind box, if the exhaust gas temperature T1 of the first monitoring wind box is higher than 15.7% T max , then appropriately reduce the air volume to reduce the combustion intensity; if T1 is lower than 12.3% T max , then appropriately increase the air volume to increase the combustion intensity;

[0026] S32, with 16.5% T max ~20.7%T max As the standard exhaust gas temperature of the second monitoring wind box, if the exhaust gas temperature T2 of the second monitoring wind box is at 16.5% T max ~20.7%T maxIf T2 is higher than 20.7% T max , while continuing to perform the measures in step S31, nitrogen is sprayed onto the surface of the sintering material to reduce the vertical sintering speed; if T2 is lower than 16.5% T max , while continuing to perform the measures in step S31, spray oxygen onto the surface of the sintering material to increase the vertical sintering speed;

[0027] S33, with 24.6% T max ~31%T max As the standard exhaust gas temperature of the third monitoring wind box, if the exhaust gas temperature T3 of the third monitoring wind box is controlled at 24.6% T max ~31%T max If T3 is higher than 31%T max , while continuing to perform steps S31 and S32, speed up the sintering machine to avoid over-burning; if T3 is lower than 24.6% T max While continuing to execute steps S31 and S32, reduce the speed of the sintering machine to avoid under-firing.

[0028] In step S31, the adjustment amount of the air volume is calculated according to the following formula:

[0029]

[0030] Where ΔQ represents the adjustment amount of sintering air volume (unit: m 3 / h);

[0031] A—Material layer area (unit: m 2 );

[0032] h m —Original material height (m);

[0033] P n —Blowing box negative pressure (kpa);

[0034] Cp—represents the specific heat capacity of sintering air (unit: J / (kg·℃));

[0035] ρ—denotes the density of sintering air (unit: kg / m 3 );

[0036] ΔT1—represents the standard median temperature of the exhaust gas of the first monitoring wind box 14%T max The difference between the actual exhaust gas temperature T1 of the first monitoring wind box (unit: °C).

[0037] In step S32, the blowing flow rate of nitrogen is 0.08ΔT2~0.11ΔT2 m 3 / h·℃, the oxygen injection flow rate is 0.09ΔT2~0.12ΔT2 m 3 / h·℃; where ΔT2 is the standard median temperature of the exhaust gas of the second monitoring wind box 18.6%T max The absolute value of the difference between the actual monitored exhaust gas temperature T2.

[0038] In step S33, the adjustment amount of the sintering machine speed is 0.007ΔT3~0.00875ΔT3 m / s·℃; wherein ΔT3 is the standard median temperature of the exhaust gas of the third monitoring wind box 27.8%T max The difference between the actual monitored exhaust gas temperature T3.

[0039] The beneficial effects of the present invention are:

[0040] The present invention proposes a sintering method for accurately controlling the sintering endpoint temperature. According to the real-time parameters of the sintering process, the sintering state is reasonably judged, and the control parameters are effectively adjusted in time. The sintering endpoint position and the sintering endpoint temperature can be controlled within the predicted range, and the occurrence of over-burning and under-burning is eliminated. Ultimately, the purpose of maintaining quality, increasing production and reducing costs is achieved, precious time is gained for production adjustment, and the stable and smooth operation of the entire production process is promoted.

[0041] The method of the present invention fully considers the dynamic changes of the sintering process, adjusts the parameters affecting the sintering process one by one, and the adjustment range is not large, thereby effectively maintaining the stability of the sintering control.

[0042] The method of the present invention can be applied to sintering systems of different specifications and volumes, and has wide adaptability and versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is a schematic diagram of a quadratic curve of the windbox position and the windbox exhaust gas temperature;

[0044] Figure 2 It is a schematic diagram for comparing the exhaust gas temperature prediction curve and the exhaust gas temperature measured curve of Example 1. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present invention are described clearly and completely below in conjunction with the accompanying drawings of the present invention. In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0046] The directions or their approximate terms described throughout the present invention, such as "front", "rear", "left", "right", "up (top)", "down (bottom)", "inside", "outside", "side", etc., are mainly used with reference to the directions of the accompanying drawings. Each direction or its approximate terms are only used to assist in the explanation and understanding of the embodiments of the present invention, and are not used to limit the present invention.

[0047] A sintering method capable of accurately controlling the sintering endpoint comprises the following steps:

[0048] S1. Collect the temperature data of the exhaust gas from each wind box, construct a curve equation of the wind box position and the exhaust gas temperature, and calculate the wind box number corresponding to the sintering end point and the wind box exhaust gas temperature at the sintering end point;

[0049] S2. According to the estimated wind box position of the sintering end point, three monitoring wind boxes are selected at appropriate positions upstream thereof to monitor the exhaust gas temperature in real time;

[0050] S3. According to the three monitoring bellows exhaust gas temperatures, by monitoring the deviation between the bellows exhaust gas temperature and the predicted temperature, the sintering condition is adjusted in time to reduce the deviation, so as to ensure that the sintering end point position and the sintering end point temperature reach the predicted range of step S1.

[0051] Each step is described and explained in detail below.

[0052] Regarding step S1,

[0053] Sintering endpoint control is based on the reasonable prediction of sintering endpoint. The position of sintering endpoint reflects the combustion status of materials, directly affects the output quality index of sintered ore, and is one of the important signs to judge whether the sintering process is normal or not. Therefore, the prediction of sintering endpoint has become an important part of the current sintering process control. Only by reasonably predicting the position of sintering endpoint can the sintering control effect be guaranteed and the fluctuation of sintering endpoint position be reduced.

[0054] The state of the sintering process includes two aspects: the permeability state and the thermal state. The permeability state determines the smooth progress of the sintering process, while the thermal state is an intuitive reflection of the process state. After the material surface is ignited, the fuel on the surface is ignited and begins to burn, causing the temperature of the air passing through the material layer to rise. As the sintering process proceeds, the combustion zone gradually moves downward. Due to the automatic heat storage effect of the lower material layer and the disappearance of the condensation phenomenon, the exhaust gas temperature continues to rise. When the front edge of the combustion zone reaches the grate bar, the exhaust gas temperature rises sharply until the entire material layer is burned through and reaches the end of sintering, and the exhaust gas temperature is the highest. Thereafter, due to the end of the combustion effect, the exhaust gas temperature drops. It can be seen that the sintering temperature is positively correlated with the exhaust gas temperature, and the end point can be predicted by analyzing the exhaust gas temperature, a thermal state indicator.

[0055] Through the analysis of the sintering process mechanism, it can be seen that when the sintering machine trolley speed is too slow, the exhaust gas temperature will increase starting from the middle bellows, and vice versa, the exhaust gas temperature of the middle and rear bellows will decrease. It can be seen that the change of the exhaust gas temperature starting from the middle bellows to the rear bellows can directly reflect the sintering state of the sintering machine. In addition, during the sintering process, as the sintering process proceeds, the temperature of the material layer becomes higher and higher, the combustion zone tends to thicken, the liquid phase increases, and the air permeability deteriorates, making the bellows exhaust gas temperature T i (i is the corresponding bellows number) is getting higher and higher, and the bellows negative pressure P becomes larger; when sintering reaches a certain extent, the permeability of sintered ore increases, and at this time Ti still tends to rise, but the bellows negative pressure P tends to decrease. The closer the sintering process is to completion, the closer the combustion zone is to the trolley surface. Only after sintering is completed, Ti tends to decrease, and the P value tends to stabilize. Therefore, the moment the temperature of the bellows exhaust gas rises to the highest point and then begins to decline, the position of the bellows is the sintering end point. By collecting the data of the exhaust gas temperature of each bellows, the distribution curve of the temperature field along the direction of the trolley movement can be obtained, and the sintering end point can be indirectly predicted based on the trend of the curve.

[0056] Generally speaking, the sintering endpoint is mostly controlled at the position of the second to last bellows or the third to last bellows. However, since the sintering endpoint involves many factors and cannot be directly monitored, and human judgment is inevitably blind, it is necessary to collect and count data to more accurately determine the position and temperature of the sintering endpoint. Through the collection and summary of a large amount of windbox exhaust gas temperature, it is found that the change trend of the windbox exhaust gas temperature with the change of the windbox position is a quadratic curve, such as Figure 1 As shown; a quadratic curve equation is constructed with the bellows position as the horizontal coordinate and the bellows exhaust gas temperature as the vertical coordinate, and then the sintering end point position and sintering end point temperature are calculated.

[0057] It should be emphasized that the temperature data of the wind box exhaust gas in step S1 is collected in at least four batches to ensure that the data is representative.

[0058] The bellows position X i , wind box exhaust gas temperature T i The quadratic relationship is:

[0059] T i =AX i 2 +BX i +C

[0060] In the formula, X i is the bellows position;

[0061] T i is the windbox exhaust gas temperature, in °C;

[0062] i is a natural number, and its value is 1, 2, ..., n; n is the total number of bellows;

[0063] A, B, and C are all constant coefficients, and A is taken from [-43, -32], B is taken from [1212, 1421], and C is taken from [-11986, -10865].

[0064] The calculation process of the constant coefficients A, B, and C is:

[0065] Set the coordinates (X i , T i ) are sequentially substituted into the above quadratic curve equation to obtain a linear equation group about the relationship between temperature and position near the sintering end point. After formula conversion, the constant coefficients A, B, and C can be solved. When the calculated values ​​of the constant coefficients A, B, and C meet the above value ranges, control can be performed according to the following steps; if the calculated values ​​of the constant coefficients exceed the above value ranges, it means that the process or equipment of the sintering system has obvious abnormalities, which need to be checked and corrected in time.

[0066] The calculation formula for constant coefficients A, B, and C is:

[0067]

[0068] After the constant coefficients A, B, and C are determined, the estimated position X of the sintering end point can be calculated. max , Sintering end point estimation exhaust gas temperature T max :

[0069]

[0070] It should be noted that the X calculated is often max If the value is not an integer, take the nearest integer; T max Usually an integer.

[0071] In the step S2,

[0072] According to the changing rules of the temperature and negative pressure of each wind box during the sintering process, three wind boxes at appropriate positions are selected as monitoring wind boxes, and the real-time sintering status is characterized by their exhaust gas temperature. Specifically: the wind box at the midpoint is selected as the first monitoring wind box, the second wind box behind the first monitoring wind box is selected as the second monitoring wind box, and the fourth wind box at the front end of the predicted sintering end wind box is selected as the third monitoring wind box. Based on the exhaust gas temperature data of the three monitoring wind boxes, the deviation from the predicted sintering process can be determined, and the control parameters can be adjusted in time.

[0073] It should be noted that when the total number of bellows n is an even number, the first The bellows is used as the first monitoring bellows; when the total number of bellows n is an odd number, the first The bellows is used as the first monitoring bellows.

[0074] The exhaust gas temperatures of the three monitoring bellows directly represent the degree of sintering. The sintering operators compare the exhaust gas temperature values ​​of each monitoring bellows with the standard exhaust gas temperature of the bellows at each position to determine whether the sintering degree at the risk point is normal. If it is abnormal, the sintering conditions are adjusted in real time according to the deviation and the deviation is corrected. Through three rounds of correction and adjustment, it is ensured that the deviation is completely corrected when the predicted sintering end position is reached.

[0075] The step S3 specifically includes the following steps:

[0076] S31, with 12.3% T max ~15.7%T max As the exhaust gas standard temperature of the first monitoring wind box, if the exhaust gas temperature T1 of the first monitoring wind box is higher than 15.7% T max , then appropriately reduce the air volume to reduce the combustion intensity; if the exhaust gas temperature T1 of the first monitoring wind box is lower than 12.3% T max , then adjust the air volume appropriately to increase the combustion intensity.

[0077] The air volume adjustment is calculated according to the following formula:

[0078]

[0079] Where ΔQ represents the adjustment amount of sintering air volume (unit: m 3 / h);

[0080] A—Material layer area (unit: m 2 );

[0081] h m —Original material height (m);

[0082] P n —Blowing box negative pressure (kpa);

[0083] Cp—represents the specific heat capacity of sintering air (unit: J / (kg·℃));

[0084] ρ—denotes the density of sintering air (unit: kg / m 3 );

[0085] ΔT1—represents the standard median temperature of the exhaust gas of the first monitoring wind box 14%T max The difference between the actual exhaust gas temperature T1 of the first monitoring wind box (unit: °C).

[0086] For the same sintering system, the material layer area, original material height, sintering air specific heat capacity, sintering air density, and wind box negative pressure are generally constant, and the sintering air volume and sintering air exhaust gas temperature are proportional. When T1<12.3%T max When ΔT1 is positive, and ΔQ is positive, it means that the air volume needs to be increased. The increase in air volume accelerates sintering and increases the sintering temperature rapidly. When T1>15.7%T max When ΔT1 is negative, and then ΔQ is negative, it means that the air volume needs to be reduced. By reducing the air volume, the sintering is delayed, the sintering temperature is appropriately reduced, and the sintering condition tends to be stable.

[0087] It should be noted that during the production operation, the actual air volume adjustment is allowed to be ±0.15m 3 / h floating amount.

[0088] S32, with 16.5% T max ~20.7%T max As the exhaust gas standard temperature of the second monitoring wind box, through the adjustment of step S31, if the exhaust gas temperature T2 of the second monitoring wind box is between 16.5% T max ~20.7%T max If the value is within the range, then the operation of step S31 is maintained without any other adjustment;

[0089] If the exhaust gas temperature T2 of the second monitoring wind box is higher than 20.7% T max , while continuing to execute the measures in step S31, nitrogen is sprayed onto the surface of the sintering material to dilute and suppress the smoke and air passing through the material layer, reduce the oxygen content required for the combustion process, and thus reduce the vertical sintering speed;

[0090] If the exhaust gas temperature T2 of the second monitoring wind box is lower than 16.5% T max While continuing to execute the measures in step S31, oxygen is sprayed onto the surface of the sintering material to increase the combustion aid in the flue gas and air passing through the material layer, increase the oxygen content required for the combustion process, accelerate carbon combustion, and thus increase the vertical sintering speed.

[0091] The nitrogen injection flow rate is 0.08ΔT2~0.11ΔT2 m 3 / h·℃, the oxygen injection flow rate is 0.09ΔT2~0.12ΔT2 m 3 / h·℃. ΔT2 is the standard median temperature of the exhaust gas of the second monitoring wind box, 18.6%T max The absolute value of the difference between the actual monitored exhaust gas temperature T2 (unit: ℃).

[0092] It should be noted that during the production operation, the actual nitrogen injection flow rate and oxygen injection flow rate control are allowed to have a deviation of ±0.10m 3 / h floating amount.

[0093] A gas spraying device for spraying nitrogen or oxygen is installed above the sintering trolley at the rear end of the second monitoring wind box, and the specific type of spraying gas is selected according to the measured exhaust gas temperature of the second monitoring wind box.

[0094] The gas spraying device includes a main gas supply pipeline, a gas branch pipeline, a nozzle, a flow control valve, a cut-off valve, a signal valve, etc. The nitrogen input pipe and the oxygen input pipe are respectively connected to the main gas supply pipeline of the gas spraying device, and automatic cut-off valves are respectively arranged on the nitrogen input pipe and the oxygen input pipe to realize the switching of nitrogen and oxygen. The main gas supply pipeline is connected to the gas branch pipeline, and the gas branch pipeline is installed horizontally (arranged horizontally with the sintering machine trolley). A hole is opened on each branch pipeline and a spraying gas nozzle is installed. After the nitrogen / oxygen passes through the main gas supply pipeline and the branch pipeline, it is sprayed onto the surface of the sintering trolley through the nozzle.

[0095] A gas flow control valve is arranged on the main gas supply pipeline, and the opening of the gas flow control valve is controlled and adjusted by the main control mechanism; the measured exhaust gas temperature of the second monitoring bellows is fed back to the main control mechanism, and then the main control mechanism adjusts the opening of the gas flow control valve, thereby realizing the flow control of nitrogen / oxygen.

[0096] The lateral arrangement width of the nozzles is consistent with the width of the sintering machine trolley, and the interval between two nozzles is 8 cm; the nozzles are evenly arranged along the length direction of the sintering machine, and the spacing between each row of air jet pipelines is 12 cm.

[0097] The gas supply pressure of nitrogen and oxygen is 0.4~0.5mPa, the diameter of the main gas supply pipeline is DN200, and the gas supply volume is >800m 3 / h, the surface spraying gas branch pipeline is laid with φ6 steel pipe, the nozzle is fixed by drilling + sleeve thread, the nozzle is a shower type nozzle with a coverage radius of R5.

[0098] S33, with 24.6% T max ~31%T max As the exhaust gas standard temperature of the third monitoring wind box, through the adjustment of steps S31 and S32, if the exhaust gas temperature T3 of the third monitoring wind box is controlled at 24.6% T max ~31%T max If it is within the range, no additional adjustment is required;

[0099] If the exhaust gas temperature T3 of the third monitoring wind box is higher than 31% T max , while continuing to perform steps S31 and S32, speed up the sintering machine to avoid over-burning;

[0100] If the exhaust gas temperature T3 of the third monitoring wind box is lower than 24.6% T maxWhile continuing to execute steps S31 and S32, reduce the speed of the sintering machine, increase the sintering time, and avoid under-firing.

[0101] The adjustment amount of the sintering machine speed is 0.007ΔT3~0.00875ΔT3 m / s·℃. The ΔT3 is the standard median temperature of the exhaust gas of the third monitoring wind box 27.8%T max The difference between the actual monitored exhaust gas temperature T3 (unit: ℃).

[0102] When T3>31%T max , ΔT3 is positive, the speed adjustment is positive, and the speed increases. max , ΔT3 is a negative value, the machine speed adjustment amount is a negative value, and the machine speed decreases.

[0103] It should be noted that during the production operation, the actual adjustment amount of the sintering machine speed is allowed to fluctuate by ±0.007m / s.

[0104] The method of the present invention is further described in detail below by way of examples.

[0105] Example 1

[0106] Taking a sintering unit of our company as an example, the sintering car has a capacity of 230m 3 There are 18 wind boxes in total, and the material layer area is 2.13m 2 The original material height is 0.9m, the wind box negative pressure is 13.6KPa, the sintering air specific heat capacity is 1.34J / (kg·℃), and the density is 0.898kg / m 3 , machine speed 2.0m / min.

[0107] S1. Collect the temperature data of the exhaust gas from each wind box, and calculate the wind box number corresponding to the sintering end point and the wind box exhaust gas temperature at the sintering end point;

[0108] In actual operation, the exhaust gas temperature detection value corresponding to the wind box position at a certain moment is shown in Table 1:

[0109] Table 1 Wind box exhaust gas temperature detection value

[0110]

[0111] From the data in the table, it can be seen that the exhaust gas temperature corresponding to the 17# wind box position is the highest among the four sets of data. Therefore, the temperatures of the 16# wind box, 17# wind box, and 18# wind box are substituted into the formula to calculate the constant coefficients A, B, and C, and then calculate the sintering end point position X max The calculation results are shown in Table 2.

[0112] Bellows position X 16# 17# 18# A B C <![CDATA[X max ]]> Group 1 448 479 429 -40.5 1367.5 -11064 16.883 Group 2 402 449 416 -40 1367 -11230 17.088 Group 3 442 487 452 -40 1365 -11158 17.063 Group 4 430 474 438 -40 1364 -11154 17.05 average value 431 472 434 -40.1 1365.9 -11151.5 17.02

[0113] Through calculation, the numerical ranges of constant coefficients A, B, and C are all within the numerical range defined in the present invention, and the data are reasonable. The four groups of average values ​​of constant coefficients A, B, and C are substituted into the formula. Through the formula calculation, X max It is 17.02, and the closest 17# wind box is taken as the predicted sintering end point.

[0114] In order to ensure the accuracy of the above calculation process, the deformation formula is used for verification.

[0115] The deformation formula is:

[0116] Among them, T i is the temperature of the wind box with the highest exhaust gas temperature, T i-1 , T i+1 The temperatures of the two windboxes at the front and rear ends of the windbox with the highest exhaust gas temperature.

[0117] Substitute the exhaust gas temperature of the first group of 16#, 17#, and 18# wind boxes into the deformation formula,

[0118]

[0119] The above calculation results are consistent, which proves that the curve equation of the present invention has high accuracy. Combined with the experience of the workers on site, the predicted position of the sintering end point is determined to be the 17# wind box.

[0120] End point temperature T max =AX max 2 +BX max +C=-40.1*17 2 +1365.9*17-11151.5=480℃.

[0121] S2. According to the estimated wind box position at the sintering end point, three monitoring wind boxes are selected at appropriate positions at the front end thereof to monitor the exhaust gas temperature in real time;

[0122] Since the total number of windboxes n of this sintering unit is 18, the predicted position of the sintering end point is windbox #17. Therefore, windbox #9 (n / 2) is selected as the first monitoring windbox, windbox #11 is selected as the second monitoring windbox, and windbox #13 is selected as the third monitoring windbox.

[0123] S3, according to the three monitoring bellows exhaust gas temperatures, by monitoring the deviation between the bellows exhaust gas temperature and the predicted temperature, the sintering situation is adjusted in real time to reduce the deviation, to ensure that the sintering end point position and the sintering end point temperature are controlled at the predicted point in step S1, to avoid over-burning or under-burning. The specific process is:

[0124] S31. Take 59℃~75℃ as the standard temperature of the exhaust gas of the first monitoring bellows. The measured temperature T1 of the exhaust gas of the first monitoring bellows is 78℃, which is higher than 75℃. The air volume should be appropriately reduced to reduce the severity of combustion.

[0125] After calculation, the air volume adjustment amount is:

[0126]

[0127] S32. Take 79°C to 99°C as the standard temperature of the exhaust gas of the second monitoring bellows. The actual measured temperature T2 of the exhaust gas of the second monitoring bellows is 86°C, which is within the standard temperature range. Therefore, the regulated air volume of S31 is maintained without further adjustment.

[0128] S33, taking 118℃~149℃ as the standard temperature of the exhaust gas of the third monitoring bellows, the actual measured temperature T3 of the exhaust gas of the third monitoring bellows is 124℃, which is within the standard temperature range, so the regulated air volume of S31 is maintained without further adjustment.

[0129] The actual measured temperature of the exhaust gas from the 17# wind box (predicted sintering end point position) is 468°C, which is not much different from the predicted sintering end point temperature of 472°C.

[0130] Collect the predicted temperature of each wind box and the measured temperature during sintering, see Figure 2 It can be seen that the trends of the two curves are basically consistent, and the sintering process basically proceeds according to the predicted process.

[0131] Embodiment 2 to Embodiment 4

[0132] The method of the present invention is used in sintering systems of different volumes, and the specific conditions are shown in the following table.

[0133]

[0134]

[0135] It can be seen from the data of Examples 2 to 4 that, for sintering systems of different volumes, the method of the present invention can achieve accurate control of the sintering endpoint position and the sintering endpoint temperature, avoid over-burning and under-burning, and maximize the quality of the sintered ore, and has wide adaptability and versatility.

[0136] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A sintering method capable of accurately controlling the sintering endpoint, characterized in that The following steps are involved: S1. Collect the temperature data of the exhaust gas from each wind box, construct the curve equation of the wind box position and the exhaust gas temperature, and calculate the wind box number X corresponding to the sintering end point. max , and the wind box exhaust gas temperature T at the end of sintering max ; S2. According to the estimated wind box position of the sintering end point, three monitoring wind boxes are selected at appropriate positions upstream thereof to monitor the exhaust gas temperature in real time; S3. According to the three monitoring bellows exhaust gas temperatures, by monitoring the deviation between the bellows exhaust gas temperature and the predicted temperature, the sintering condition is adjusted in time to reduce the deviation, so as to ensure that the sintering end point position and the sintering end point temperature reach the predicted range of step S1.

2. A sintering method capable of accurately controlling the sintering endpoint according to claim 1, characterized in that: In step S1, the bellows position X i , wind box exhaust gas temperature T i The quadratic relationship is: T i =AX i 2 +BX i +C In the formula, X i is the bellows position; T i is the windbox exhaust gas temperature, in °C; i is a natural number, and its value is 1, 2, ..., n; n is the total number of bellows; A, B, and C are all constant coefficients, and A is taken from [-43, -32], B is taken from [1212, 1421], and C is taken from [-11986, -10865].

3. A sintering method capable of accurately controlling the sintering endpoint according to claim 2, characterized in that: The temperature data of the wind box exhaust gas is collected in no less than four batches.

4. A sintering method capable of accurately controlling the sintering endpoint according to claim 1, characterized in that: In step S2, the wind box located at the midpoint is selected as the first monitoring wind box, the second wind box behind the first monitoring wind box is selected as the second monitoring wind box, and the fourth wind box in front of the predicted sintering end point wind box is selected as the third monitoring wind box.

5. A sintering method capable of accurately controlling the sintering endpoint according to claim 1, characterized in that: The step S3 specifically includes the following steps: S31, with 12.3% T max ~15.7%T max As the exhaust gas standard temperature of the first monitoring wind box, if the exhaust gas temperature T1 of the first monitoring wind box is higher than 15.7%T max , then appropriately reduce the air volume to reduce the combustion intensity; if T1 is lower than 12.3%T max , then appropriately increase the air volume to increase the combustion intensity; S32, with 16.5% T max ~20.7%T max As the standard exhaust gas temperature of the second monitoring wind box, if the exhaust gas temperature T2 of the second monitoring wind box is 16.5%T max ~20.7%T max If T2 is higher than 20.7%T max , while continuing to execute the measures in step S31, nitrogen is sprayed onto the surface of the sintering material to reduce the vertical sintering speed; if T2 is lower than 16.5%T max , while continuing to perform the measures in step S31, spray oxygen onto the surface of the sintering material to increase the vertical sintering speed; S33, with 24.6% T max ~31%T max As the standard exhaust gas temperature of the third monitoring wind box, if the exhaust gas temperature T3 of the third monitoring wind box is controlled at 24.6%T max ~ 31%T max If T3 is higher than 31%T max , while continuing to perform steps S31 and S32, speed up the sintering machine to avoid over-burning; if T3 is lower than 24.6%T max While continuing to execute steps S31 and S32, reduce the speed of the sintering machine to avoid under-firing.

6. A sintering method capable of accurately controlling the sintering endpoint according to claim 5, characterized in that: In step S31, the adjustment amount of the air volume is calculated according to the following formula: ΔQ= Cp * p * ΔT1 Wherein, ΔQ represents the adjustment amount of sintering air volume (unit: m³ / h); A—Material layer area (unit: m 2 ); h m —Height of original material (m); P n —Blowing box negative pressure (kpa); Cp—indicates the specific heat capacity of sintering air (unit: J / (kg·℃)); ρ—indicates the density of sintering air (unit: kg / m³); ΔT1—represents the standard median temperature of the exhaust gas of the first monitoring wind box 14%T max The difference between the actual exhaust gas temperature T1 of the first monitoring wind box (unit: ℃).

7. A sintering method capable of accurately controlling the sintering endpoint according to claim 5, characterized in that: In step S32, the injection flow rate of nitrogen is 0.08ΔT2~0.11ΔT2 m³ / h∙℃, and the injection flow rate of oxygen is 0.09ΔT2~0.12ΔT2 m³ / h∙℃; wherein ΔT2 is the standard median temperature of the exhaust gas of the second monitoring wind box, 18.6%T max The absolute value of the difference between the actual monitored exhaust gas temperature T2.

8. A sintering method capable of accurately controlling the sintering endpoint according to claim 5, characterized in that: In step S33, the adjustment amount of the sintering machine speed is 0.007ΔT3~0.00875ΔT3 m / s∙℃; wherein ΔT3 is the standard median temperature of the exhaust gas of the third monitoring wind box 27.8%T max The difference between the actual monitored exhaust gas temperature T3.

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