Method and system for determining position of sintering finishing line

Abstract

The invention provides a method and system for determining the position of a sintering finish line, and the method comprises the steps: obtaining the current combustion injection flow, judging whether the current combustion injection flow is within an effective injection flow range or not, and determining the position of the sintering finish line when the current combustion injection flow is within the effective injection flow range. And according to the current fuel gas injection flow and a pre-established flow position algorithm model, determining an operation sintering finish line position corresponding to the current fuel gas injection flow, wherein the flow position algorithm model comprises a mapping relation between the fuel gas injection flow and the operation sintering finish line position. According to the method, the position of the sintering end point line is timely and accurately determined according to the fuel gas injection flow through the pre-established flow position algorithm model, so that the position of the sintering end point is accurately judged in advance, and corresponding measures are conveniently taken in advance to control the sintering end point.

Description

Technical Field

[0001] The present invention relates to the technical field of sintering, and in particular to a method and a system for determining a sintering finish line position. Background Art

[0002] With the rapid development of modern industry, the scale of steel production is getting larger and larger, and energy consumption is also increasing. Energy conservation and environmental protection indicators are becoming more and more important factors to consider in the steel production process. In steel production, iron-containing raw ore needs to be processed by the sintering system before entering the blast furnace for smelting. That is, various powdered iron-containing raw materials are mixed with appropriate amounts of fuel (coal powder, coke powder) and flux, and appropriate amounts of water. After mixing and balling, they are placed on the sintering trolley for roasting, so that a series of physical and chemical changes occur, forming sintered ore that is easy to smelt. This process is called sintering.

[0003] The sintering end point is an important process parameter that reflects the sintering quality, output and cost. The sintering end point can indicate the end point where the material layer on the sintering machine trolley is roasted, that is, the sintering end position. Controlling the sintering end point at the expected sintering end point position is the key to improving the yield and making full use of the sintering area. If the actual sintering end point is earlier than the expected sintering end point position, it means that there is overburning, and the production capacity of the sintering machine (for example, the sintering area corresponding to the next few fans starting from the actual combustion end point) is not fully utilized, resulting in a reduction in the output / capacity of the sintered ore; if the actual sintering end point lags behind the expected sintering end point position, it means that the mixed material on the sintering machine trolley has run to the tail of the machine for unloading before it has time to be completely roasted. At this time, there is still a lot of raw material between the combustion zone corresponding to the actual sintering end point and the bottom material layer, resulting in underburning, which ultimately affects the quality of the sintered ore.

[0004] In the prior art, the sintering end point is generally detected by arranging multiple thermocouples / temperature sensors that can detect the temperature of the wind box flue gas on the sintering machine body, fitting the temperature values ​​of the multiple thermocouples to obtain a secondary temperature curve, and indirectly determining the sintering end point based on the inflection point of the secondary temperature curve (corresponding to the position with the highest temperature in the combustion zone). This method requires the deployment of a large number of thermocouples, which is costly and difficult to guarantee prediction accuracy.

[0005] In view of this, it is necessary to propose a method and system for determining the position of the sintering finish line to solve or at least alleviate the above-mentioned defects. Summary of the invention

[0006] The main purpose of the present invention is to provide a method and system for determining the position of the sintering end line, so as to solve the technical problems that the existing technology for detecting the sintering end position is generally to arrange a plurality of thermocouples on the sintering machine that can detect the temperature of the wind box flue gas, which requires the arrangement of a large number of thermocouples, is costly, and the prediction accuracy is difficult to guarantee.

[0007] To achieve the above object, the present invention provides a method for determining the position of a sintering finish line, comprising the steps of:

[0008] S1, obtaining the current combustion injection flow rate, and determining whether the current combustion injection flow rate is within the effective injection flow rate range;

[0009] S2. When the current gas injection flow rate is within the effective injection flow rate range, the calculated sintering end line position corresponding to the current gas injection flow rate is determined according to the current gas injection flow rate and a pre-established flow position algorithm model; wherein the flow position algorithm model includes a mapping relationship between the gas injection flow rate and the calculated sintering end line position.

[0010] Preferably, the "flow location algorithm model" in step S2 is specifically:

[0011]

[0012] Among them, S is the position of the calculation sintering finish line, H is the total thickness of the material layer on the sintering trolley, PH is the thickness of the bottom material layer, SV is the speed of the sintering trolley, c is the thickness of the solid combustion zone, k1 is the heat transfer coefficient, Q is the gas fuel flow rate, h is the gas combustion heat, t is the duration of gas injection, m is the unit sintering machine material amount, z is the material layer thickness below the gas combustion zone, and Cp is the average specific heat capacity of the sintering material.

[0013] Preferably, the "flow location algorithm model" in step S2 is obtained specifically through the following steps:

[0014] S201, according to the formula Determine the time t1 when the pulverized coal preheating temperature reaches the ignition temperature; where Tc is the pulverized coal ignition temperature, T0 is the initial material temperature, and V is the material layer heating rate;

[0015] S202, according to the formula Determine the total time tt for solid fuel combustion, where t2 is the time for the charcoal powder to fully burn;

[0016] S203, according to the formula Formula ΔT=K1*Q and formula Determine

[0017] S204, according to the formula And the formula Determine Among them, t2 is 40, T c Take 1073, T0 takes 330, c takes 20;

[0018] S205, according to the formula and formula Determine

[0019] Preferably, the volume of the fuel gas blown into the sintering material surface is at most 0.8% of the volume of the air entering the sintering material surface.

[0020] Preferably, the step S2 further includes the following steps:

[0021] When the calculated sintering finish line position is not within the preset range, a warning instruction is sent to the target object.

[0022] The present invention also provides a system for determining the position of the sintering end line, comprising a sintering machine body, a gas injection device and a control system, wherein the sintering machine body comprises a material distribution area, an ignition furnace area and a holding furnace area, a gas injection area is provided downstream of the holding furnace area, and the gas injection device is provided in the gas injection area, wherein:

[0023] The gas injection device comprises a gas injection main pipe and a plurality of gas injection branch pipes arranged in parallel along the width direction of the sintering machine trolley; the gas injection main pipe is provided with the gas regulating valve; each of the gas injection branch pipes is connected to the gas injection main pipe, and a plurality of fuel nozzles for injecting gas toward the top surface of the sintering material layer are installed at the bottom of each gas injection branch pipe;

[0024] The gas injection device is connected to the control system, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method for determining the sintering finish line position as described above are implemented.

[0025] Preferably, the plurality of gas injection branch pipes are evenly arranged along the width direction of the sintering machine trolley; and the plurality of fuel nozzles of each gas injection branch pipe are evenly arranged along the length direction of the gas injection branch pipe.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention provides a method and system for determining the position of the sintering end line, by obtaining the current combustion injection flow rate, and judging whether the current combustion injection flow rate is within the effective injection flow rate range, when the current gas injection flow rate is within the effective injection flow rate range, the calculation sintering end line position corresponding to the current gas injection flow rate is determined according to the current gas injection flow rate and a pre-established flow position algorithm model, and the flow position algorithm model includes a mapping relationship between the gas injection flow rate and the calculation sintering end line position. The present application can timely and accurately determine and calculate the corresponding theoretical calculation position of the sintering end line according to the gas injection flow rate in the current state through the pre-established flow position algorithm model, and the theoretical calculation position can accurately reflect the sintering end line position in the current state, and can realize the accurate judgment of the sintering end line position (the actual sintering end line position is located downstream of the gas injection area) in advance. The present application does not need to lay a large number of thermocouples, greatly reducing the cost of laying a large number of thermocouples, and can ensure the prediction accuracy, so that when overburning or underburning is predicted, corresponding measures can be taken in advance to achieve the control of the sintering end point. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0029] Figure 1 It is a process flow chart of a sintering system in the prior art;

[0030] Figure 2 It is a schematic diagram of the sintered ore formation process in the prior art;

[0031] Figure 3 It is one of the cross-sectional schematic diagrams of the sintering ore formation process in the prior art;

[0032] Figure 4 The second schematic cross-sectional view of the sintering ore formation process in the prior art;

[0033] Figure 5 A side view of a schematic diagram of the overall structure of an embodiment of the present invention;

[0034] Figure 6 A top view of a schematic diagram of the overall structure of an embodiment of the present invention;

[0035] Figure 7 A schematic diagram of the formation of gas injection sintered ore in one embodiment of the present invention;

[0036] Figure 8 It is a schematic diagram of a flow chart in one embodiment of the present invention.

[0037] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0038] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0041] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0042] In order to enable those skilled in the art to fully understand the technical solution of this application, it should be known that the existing sintering system mainly includes a sintering machine trolley, a mixer, a main exhaust fan, an annular cooler and other equipment. Figure 1As shown: various raw materials are proportioned in the batching room to form a mixture. After the mixture enters the mixer for mixing and balling, it is evenly spread on the sintering machine trolley through the round roller feeder and the nine-roller distributor to form a sintering mixture layer. The ignition fan and the ignition fan start the ignition furnace, and the sintering mixture on the top layer of the sintering machine trolley is ignited in the ignition furnace. The ignited combustion zone begins to move from top to bottom, and the mixture passing through the combustion zone is roasted into sintered ore. This is the sintering process. The sintered ore obtained after sintering is crushed by a single roller crusher and then cooled in an annular cooler. Finally, it is sent to the blast furnace or finished ore bin after screening and granulation. Among them, the oxygen required for the sintering process is provided by the main exhaust fan. A number of vertically arranged bellows are arranged under the sintering machine trolley. Below the bellows is a horizontally placed large flue (or flue), which is connected to the main exhaust fan. The negative pressure wind generated by the main exhaust fan through the large flue and the bellows passes through the trolley to provide combustion-supporting air for the sintering process.

[0043] Please refer to Figure 2-4 In the existing technology, during the sintering production process, the ignited combustion zone moves from top to bottom, and the movement speed of the combustion zone is the vertical sintering speed. The sintering machine trolley moves from the head to the tail of the sintering machine, and the movement speed of the sintering machine trolley is the sintering machine speed. When the combustion zone moves to the bottom of the sintering machine trolley mixed material (the bottom material layer position), the corresponding position of the sintering machine trolley relative to the sintering machine head is the sintering end position. Figure 2 As shown in the figure, with the movement of the sintering machine trolley, the combustion zone gradually moves downward, and the mixed material passing through the combustion zone is roasted into sintered ore; Figure 3 (the combustion zone is at the top) As shown, during the sintering process, the materials in the sintering machine car can be divided into a base material layer, a mixed material layer, a combustion zone layer and a sintered ore layer from bottom to top, among which the base material layer is a finished sintered ore of a certain particle size. Figure 4 As shown, when the combustion zone moves to the base material layer, all the materials in the sintering machine trolley have been roasted into sintered ore. At this time, the corresponding position is the sintering end position, which is generally represented by the bellows number. Optionally, the combustion zone layer has a certain thickness, and the sintering end position can be understood as the bottom of the combustion zone just touching the base material layer. When the sintering end position is controlled at the second to last bellows or the first to last bellows, no raw material will be produced, the fuel utilization rate is high, the sintering efficiency is high, and the quality of the sintered ore is good. In other words, the ideal sintering end position can be regarded as a point at a fixed distance from the ignition position of the sintering material surface.

[0044] In one embodiment of the present invention, the sintering end position is controlled to be the target sintering end position when the position of the second to last bellows or the first to last bellows is set. Figure 5As shown, the speed at which the combustion zone moves downward is called the sintering speed, which is represented by LV and the unit is m / s; the thickness of the material layer on the sintering machine is represented by H and the unit is m; there is a base material under the sintering mixture, which is a finished sintered ore of a certain particle size, and its thickness can be represented by PH and the unit is m; in the process of stable sintering production, the sintering speed is considered to be a constant value. After the sintered ore passes through the ignition furnace and the sintering process begins, its sintering time ST (unit min) is

[0045] ST = (H-PH) / LV Formula 1

[0046] Controlling the sintering end point to the target sintering end point position is an important means of sintering control. During the sintering process, after the mixed material is laid on the sintering machine trolley, controlling the sintering end point at the last bellows or the second to last bellows of the sintering machine can achieve the most reasonable use of the sintering machine area. The corresponding sintering section at this time is as follows Figure 4 As shown; that is, the ideal sintering end position can be regarded as a position point within a fixed distance from the ignition position of the sintering material surface; that is, the moving distance S of the rear car after the ignition of the sintering material surface has an optimal value S0, and the position corresponding to S0 is the target sintering end position.

[0047] like Figure 2 As shown in the figure, within the sintering time ST, the relationship between the sintering machine trolley moving distance S (unit: m), the sintering machine trolley speed SV (unit: m / min), and the sintering time ST is shown in formula 2:

[0048] S=ST*SV Formula 2

[0049] Combining (1) and (2) we can get

[0050]

[0051] In summary, according to formula (3), it can be concluded that the existing technologies for adjusting the sintering end point can be divided into three categories: the existing methods for adjusting the sintering end point are relatively simple. The first is to adjust the sintering end point by controlling the sintering trolley speed SV; the second is to adjust the sintering speed LV by controlling the sintering main exhaust fan system (negative pressure, air volume) to adjust the sintering end point; the third is to adjust the sintering end point by controlling the sintering material layer thickness H. These adjustment methods have the technical problem of being too dependent on the main structure of the sintering system. This dependence is reflected in, for example, that adjusting the machine speed will cause frequent changes in the equipment state and the equipment is in an unstable working state. If the material layer thickness is adjusted frequently, it will cause fluctuations in output / capacity. If the fan air volume is adjusted frequently, it will also cause the equipment to be in an unstable working state, increasing the technical problems of equipment wear and energy consumption.

[0052] Please refer to Figure 5-6Through the study of sintering technology, during the sintering process, injecting gas into the sintering material and using gas instead of carbon to participate in the sintering process can affect the vertical combustion speed (i.e., sintering speed LV), thereby affecting the sintering end position. Specifically, after the gas is sprayed onto the sintering material surface, it enters the sintering material layer with the air. When the gas reaches the temperature area above the solid combustion zone that is higher than the gas combustion point, the gas is ignited to form a gas combustion zone suspended above the solid combustion zone; the gas combustion zone will burn downward synchronously with the solid combustion zone, and the heat released by the gas combustion zone will be quickly conducted downward and superimposed on the solid combustion zone, thereby accelerating the combustion speed of the solid combustion zone and increasing the combustion temperature of the solid combustion zone.

[0053] After the gas is blown into the sintering material surface, the sintered ore is formed as shown in the attached diagram. Figure 7 As shown, Figure 7 As shown, after the gas is sprayed onto the sintering material surface, it enters the sintering material layer along with the air. When the gas reaches the temperature area above the solid combustion zone and is higher than the gas combustion point, the gas is ignited to form a gas combustion zone suspended above the solid combustion zone.

[0054] The gas combustion zone will burn downward synchronously with the solid combustion zone. The heat released by the gas combustion zone is quickly conducted downward and superimposed on the solid combustion zone, thereby accelerating the combustion speed of the solid combustion zone and increasing the combustion temperature of the solid combustion zone.

[0055] In practical applications, considering the safety of gas and other issues, the maximum volume fraction of gas injection is 0.8%, that is, the maximum volume of gas blown into the sintering material surface is 0.8% of the volume of air entering the sintering material surface; there are solutions to the problems of nozzle arrangement and sufficient mixing of gas and air, which are not discussed in this case; the oxygen in the air consumed by the combustion of gas with a volume fraction below 0.8% has basically no effect on the combustion of solid fuel in sintered ore. The volume fraction can be linearly converted to the flow rate of the regulating valve F1. For example, the volume fraction of gas is 0.8% at the maximum flow rate L1, and the volume fraction of gas is 0.4% at 0.5 times L1;

[0056] It can be understood by those skilled in the art that, in actual production, if the actual sintering finish line is ahead of the ideal sintering finish line, it can be considered as premature sintering, and the production capacity of the sintering machine is not fully utilized, resulting in a reduction in the output of sintered ore. If the actual sintering finish line is behind the ideal sintering finish line, it can be considered as over-sintering, which ultimately affects the quality of the sintered ore.

[0057] Please refer again Figure 5-6The present invention provides a system for determining the position of a sintering end line, comprising a sintering machine body, a gas injection device and a control system, wherein the sintering machine body comprises a material distribution area, an ignition furnace area and a holding furnace area, a gas injection area is provided downstream of the holding furnace area, and the gas injection device is provided in the gas injection area, wherein the gas injection device comprises a gas injection main pipe and a plurality of gas injection branch pipes arranged in parallel along the width direction of the sintering machine trolley, each gas injection branch pipe extending along the extension direction of the sintering machine body; the gas injection main pipe is provided with the gas regulating valve; each gas injection branch pipe is connected to the gas injection main pipe, and a plurality of fuel nozzles for injecting gas toward the top surface of the sintering material layer are installed at the bottom of each gas injection branch pipe; the gas injection device is connected to the control system, and the control system comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the processor executes the computer program, the steps of the method for determining the position of a sintering end line as described below are implemented.

[0058] Optionally, the gas injection zone is arranged adjacent to the insulation furnace zone, a gas injection device is provided in the gas injection zone, a gas injection branch pipe is arranged opposite to the trolley track and is used to spray gas to the trolley on the trolley track passing through the gas injection zone, and the gas injection area is set to 15-20m along the length direction of the sintering machine body.

[0059] In addition, the gas injection main pipe is connected to an external fuel storage device (not shown in the figure). As long as a stable supply of fuel is guaranteed, a stable sintering working state can be guaranteed.

[0060] In a preferred embodiment, the plurality of gas injection branch pipes are evenly arranged along the width direction of the sintering machine trolley, and the plurality of burner nozzles of each gas injection branch pipe are evenly arranged along the length direction of the gas injection branch pipe. By evenly arranging, the effect of the entire sintering end point controlled by gas injection is more accurate (each partition can be adjusted by individually controlling each partition). In other embodiments, those skilled in the art can also adaptively adjust the spacing distance between the plurality of gas injection pipes, or adaptively adjust the spacing distance between the plurality of burner nozzles on each gas injection branch pipe. In addition, by evenly arranging, it is convenient for each sub-partition (one gas injection branch pipe can be set to correspond to one sub-partition), and targeted adjustment of the sub-partition can be achieved, thereby adjusting the uniformity of the sintered ore.

[0061] Please see attached Figure 8 The present invention provides a method for determining the position of a sintering finish line, comprising the steps of:

[0062] S1, obtain the current combustion injection flow rate, and determine whether the current combustion injection flow rate is within the effective injection flow rate range; specifically, a flow meter can be installed on the gas injection main pipe or the gas pipeline, and the current gas injection flow rate is determined by obtaining the data of the flow meter. In practical applications, considering the safety of gas and other issues, the maximum volume fraction of gas injection is 0.8%, that is, gas injection has an effective injection flow rate range. It can be understood that if the current gas injection flow rate is too large, there will be a gas safety problem. In a preferred example, the effective injection flow rate range is set to 0.005~0.1Nm 3 / s.

[0063] S2, when the current gas injection flow rate is within the effective injection flow rate range, the calculated sintering end line position corresponding to the current gas injection flow rate is determined according to the current gas injection flow rate and the pre-established flow position algorithm model; wherein the flow position algorithm model includes the mapping relationship between the gas injection flow rate and the calculated sintering end line position. It is worth noting that the flow position algorithm model of the present application is obtained through pre-theoretical derivation and verified through specific examples (specific examples below), and has high calculation accuracy. Since the flow position algorithm model includes the mapping relationship (functional relationship) between the gas injection flow rate and the calculated sintering end line position, after knowing the current gas injection flow rate, the corresponding calculated sintering end line position value can be obtained according to the model, and the value can be used to reflect the sintering end line position in the current state, so that the current sintering state can be analyzed and judged according to the value whether it is in an abnormal state, so as to facilitate subsequent regulation or early warning.

[0064] Specifically, the "flow location algorithm model" in step S2 is specifically:

[0065]

[0066] Among them, S is the position of the sintering end line, that is, the moving distance S (unit: m) of the sintering machine trolley within the sintering time ST, H is the total thickness of the material layer on the sintering trolley, unit: m, PH is the thickness of the bottom material layer, unit: m, SV is the speed of the sintering trolley, unit: m / s, c is the thickness of the solid combustion zone, unit: m, k1 is the heat transfer coefficient, dimensionless, Q is the gas fuel flow rate, unit: Nm 3 / s, h is the heat of gas combustion, unit is J / Nm 3 , t is the duration of gas injection, unit is s;

[0067] It is worth noting that m is the unit sintering machine material quantity, in kg, which can be understood as the total weight of the mixed material in the cross section of the sintering trolley corresponding to the movement of the sintering machine for 1 second, which is roughly 200-300 kg;

[0068] The specific calculation is as follows: the sintering trolley movement speed is 2.0~2.4m / min;

[0069] The sintering trolley moves 0.033-0.04m per second;

[0070] The cross-sectional area of ​​the trolley material can be calculated as 5.5*0.8 (trolley width*material layer thickness);

[0071] The specific gravity of sintered ore is 2.0t / m 3 ; (after firing)

[0072] It can be seen that the material amount per unit sintering machine is approximately 210kg to 250kg.

[0073] z is the thickness of the material layer below the gas combustion zone, in m, and Cp is the average specific heat capacity of the sintering material, in J / (kg*K).

[0074] In addition, it should be noted that S in the present application is the position of the calculated sintering end line, that is, the position where the sintering material is just ignited when the gas injection is 0 is the initial position point.

[0075] In the scheme of the present application, by obtaining the current combustion injection flow rate and judging whether the current combustion injection flow rate is within the effective injection flow rate range, when the current gas injection flow rate is within the effective injection flow rate range, the computational sintering end line position corresponding to the current gas injection flow rate is determined according to the current gas injection flow rate and a pre-established flow position algorithm model, and the flow position algorithm model includes a mapping relationship between the gas injection flow rate and the computational sintering end line position. The present application uses a pre-established flow position algorithm model, which, when other parameters are determined, can timely and accurately determine and calculate the corresponding theoretical calculated position of the sintering end line based on the current state of the gas injection flow rate. The theoretical calculated position can accurately reflect the current state of the sintering end line position, and can accurately judge the sintering end point position in advance (the actual sintering end point position is located downstream of the gas injection area). When overburning or underburning is predicted, corresponding measures can be taken in advance to control the sintering end point, rather than waiting until there are problems such as untimely predictions, vague judgment results or delayed analysis. It should also be noted that compared with the method of using deep learning (such as convolutional neural network models), this method does not require long-term production practice to obtain a large amount of sample data.

[0076] Specifically, in order to further illustrate the flow location algorithm model and facilitate those skilled in the art to understand the flow location algorithm model of the present application, the derivation process of the model is now specifically described:

[0077] First, according to the heat balance formula, the heat release power of gas fuel burning in the material layer can be calculated by formula 4:

[0078] P1=Q*h Formula 4

[0079] Where: P1: fuel heating power, unit W; Q: gas fuel flow, unit Nm 3 / s; h: Combustion heat of gas fuel, unit J / Nm 3 ;

[0080] It can be understood that part of the heat released by the combustion of the gas fuel will be directly transferred to the solid combustion zone with a thickness of c located in the lower layer, so that its initial temperature will be increased by ΔT compared with the conventional sintering temperature; part of the heat will pass through the solid combustion zone in the form of flue gas sensible enthalpy, continue to be transferred downward and add to the materials under the solid combustion zone; among them, the initial temperature increase ΔT of the material to be ignited near the solid combustion zone can be calculated by Formula 5 and Formula 6:

[0081] Secondly, the heat generated by combustion is carried away by the flue gas, heating the material under the combustion zone. After the flue gas passes through the material and solid combustion zone, the flue gas temperature will rise. By comparing the flue gas temperature of the bellows before gas injection and the flue gas temperature of the bellows after gas injection, the heat carried away by the flue gas and the heat left in the material can be calculated.

[0082] The heat remaining in the material heats all the materials below the gas combustion zone. The ratio of the heat remaining in the material to the heat taken away by the flue gas can be calculated, and the temperature rise of the material can be calculated. The gas combustion zone gradually moves downward, that is, the solid material heated by the heat of the gas combustion zone gradually decreases as the sintering machine moves forward. The flue gas passes through the sintering ore layer, the gas combustion zone, the sintering ore layer between the gas-solid combustion zone, the solid combustion zone, and the mixed material layer; the flue gas is heated by the sintering ore layer and gradually increases in temperature; after passing through the gas combustion zone and the solid combustion zone, the temperature increases and heats the lower layer materials. Because the gas combustion zone and the solid combustion zone gradually move downward, the heated lower layer materials gradually decrease;

[0083] According to the heat balance formula P2=k1*P1, (Formula 5) the heat P2 directly transferred from the gas combustion to the material below the gas combustion zone is determined; wherein P2 is the heat directly transferred from the gas combustion to the material, in units of W;

[0084] According to the formula Determine the initial temperature increase ΔT of the material to be ignited near the solid combustion zone caused by gas combustion;

[0085] Where: P2: heat directly transferred to the material by gas combustion, unit W; k1: transfer coefficient, dimensionless; (slightly different for different sintering machines, it can be regarded as a constant under the stable working condition of the same sintering machine); ΔT: initial temperature increase of solid combustion zone material brought by gas fuel, unit K; m is the material amount per unit sintering machine, unit kg; z: thickness of the material layer under the gas combustion zone, unit m; H: total thickness of the material layer, unit m; Cp: average specific heat capacity of sintering material, unit J / (kg*K); t: duration of gas injection, unit s;

[0086] The specific derivation process of formula 6 is as follows:

[0087] From the derivation of formula 5, it can be seen that the heat of P2 is transferred to the material layer below the combustion zone, and the thickness of the material layer below the combustion zone is Z; the total thickness of the material layer is H;

[0088] During the gas injection period, the materials above the gas combustion zone will not be heated by the heat provided by the gas combustion zone, and the amount of heated materials below the gas combustion zone is m*(z / H), and the duration is t;

[0089] Formula 6a can be derived

[0090]

[0091] T2: Initial material temperature; T1: Temperature of the material after being heated by the gas combustion zone

[0092] ΔT=T1-T2

[0093] Substituting formula 4 and 6a into formula 6, we can obtain:

[0094]

[0095] In formula 7, the transfer coefficient k1, the combustion heat of gas fuel h, and the average specific heat capacity Cp of sintering materials can be regarded as constants. Under the condition of stable production of the sintering machine, the total thickness of the material layer H, the material amount per unit sintering machine m, and the gas injection time t can be regarded as constants. The thickness of the material layer z under the gas combustion zone gradually decreases as the sintering machine moves forward. In the gas injection range, the average value can be taken as 0.75*H~0.85*H. The coefficient K1 can be obtained as shown in formula 8:

[0096] According to the formula P1 = Q*h, the formula P2 = k1*P1 and the formula Determine

[0097] Substituting formula 8 into formula 7, we get:

[0098] ΔT=K1*Q Formula 9

[0099] It can be seen from Formula 9 that when the sintering machine speed is stable, the initial temperature rise value of the solid combustion zone material under the gas combustion zone and the gas flow rate can be approximately regarded as a linear relationship.

[0100] As a specific implementation, the "flow location algorithm model" in step S2 is obtained by the following steps:

[0101] S201, according to the formula Determine the time t1 when the pulverized coal preheating temperature reaches the ignition temperature; where Tc is the pulverized coal ignition temperature, T0 is the initial material temperature, and V is the material layer heating rate;

[0102] S202, according to the formula Determine the total time tt for solid fuel combustion, where t2 is the time for the charcoal powder to fully burn;

[0103] S203, according to the formula Formula ΔT = K1*Q (Formula 9) and Formula Determine

[0104] S204, according to the formula And the formula Determine Among them, t2 is 40, T c Take 1073, T0 takes 330, c takes 20;

[0105] S205, according to the formula and formula Determine

[0106] It should be noted that the combustion of sintered solid fuel mainly includes four processes: 1. Preheating of carbon powder; 2. Volatile analysis; 3. Combustion of volatiles; 4. Combustion of residual carbon. The latter three processes involving complex heat transfer, mass transfer and chemical reaction coupling can be collectively referred to as the full combustion process. The total time tt of solid fuel combustion can be approximately regarded as the sum of the time t1 for the carbon powder residual heat to reach the ignition point temperature and the time t2 for the carbon powder to be fully burned. The effect of gas injection on the combustion rate of solid fuel is mainly manifested in increasing the temperature of the starting reactants, thereby reducing the preheating time t1. After the solid fuel starts to burn, the full combustion time t2 remains unchanged.

[0107] Before and after gas injection, the heat transfer coefficient between the sintering material layer and the high-temperature gas can be approximately considered unchanged. Therefore, the preheating time t1 can be calculated by formula 10:

[0108]

[0109] Where: Tc: ignition point temperature of carbon powder, unit K; T0: initial temperature of combustion zone material before injection, unit K; ΔT: initial temperature increase of combustion zone material caused by gas injection, unit K; V: material layer heating rate, unit K / s;

[0110] Therefore, the total time tt of solid fuel combustion can be calculated using formula 11:

[0111]

[0112] Obviously, the fuel thickness in the solid combustion zone divided by the total time of solid fuel combustion is the combustion speed of the solid combustion zone moving downward, and formula 12 can be obtained:

[0113]

[0114] Substituting Formula 9 into Formula 11, we get:

[0115]

[0116] Typical values ​​of relevant parameters are shown in Table 1

[0117] Table 1: Typical values ​​of relevant parameters

[0118]

[0119] Substituting typical values ​​into formula 13, we get:

[0120]

[0121] Right now

[0122]

[0123] Substituting formula 12 into formula 10, we get:

[0124]

[0125] Substituting Formula 15 into Formula 3, we obtain:

[0126]

[0127] Here are some examples:

[0128] The material layer thickness of a sintering machine is H = 0.7m, the bottom material layer thickness is PH = 0.1m, the unit sintering machine material quantity is 250kg, the sintering trolley speed is SV = 0.035m / s, the solid combustion zone thickness is c = 0.03m, the bottom material layer thickness is PH = 0.1m, the average specific heat capacity of the sintering material is Cp = 1600J / (kg*K), the gas injection time is 500s, the transfer coefficient is k1 = 0.35, and the unit gas combustion heat is h = 30000000J / Nm3 ;

[0129] When the gas injection flow rate is 0Nm 3 / s, we can calculate:

[0130]

[0131] The total length of the sintering machine is 90 meters, the length of a single wind box is 4 meters, the length from the material distribution to the ignition position is 10 meters, the length from the starting position of the solid combustion zone to the gas injection position is 10 meters, and the length of the gas injection section is 20 meters;

[0132] Without considering gas injection, the ideal sintering end point is at the tail of the sintering machine, that is, 90-14=76 meters; if the combustion zone thickness is considered to be 25mm and the material layer is considered to be 800mm, the calculated position is 74.06m; matching the actual situation, it can be seen that the above flow position model is accurate.

[0133] As another example, when the gas injection flow rate is 0.006 Nm 3 / s, we can calculate:

[0134]

[0135] As another example, when the gas injection flow rate is 0.005 Nm 3 / s, we can calculate:

[0136]

[0137] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for determining the position of a sintering finish line, characterized in that: Includes steps: S1, obtaining the current combustion injection flow rate, and determining whether the current combustion injection flow rate is within the effective injection flow rate range; S2. When the current gas injection flow rate is within the effective injection flow rate range, the calculated sintering end line position corresponding to the current gas injection flow rate is determined according to the current gas injection flow rate and a pre-established flow position algorithm model; wherein the flow position algorithm model includes a mapping relationship between the gas injection flow rate and the calculated sintering end line position.

2. The method for determining the sintering finish line position according to claim 1, characterized in that: The "flow location algorithm model" in step S2 is specifically: Among them, S is the position of the calculation sintering finish line, H is the total thickness of the material layer on the sintering trolley, PH is the thickness of the bottom material layer, SV is the speed of the sintering trolley, c is the thickness of the solid combustion zone, k1 is the heat transfer coefficient, Q is the gas fuel flow rate, h is the gas combustion heat, t is the duration of gas injection, m is the unit sintering machine material amount, z is the material layer thickness below the gas combustion zone, and Cp is the average specific heat capacity of the sintering material.

3. The method for determining the sintering finish line position according to claim 2, characterized in that: The "flow location algorithm model" in step S2 is specifically obtained through the following steps: S201, according to the formula Determine the time t1 when the pulverized coal preheating temperature reaches the ignition temperature; where Tc is the pulverized coal ignition temperature, T0 is the initial material temperature, and V is the material layer heating rate; S202, according to the formula Determine the total time tt for solid fuel combustion, where t2 is the time for the charcoal powder to fully burn; S203, according to the formula Formula ΔT=K1*Q and formula Determine S204, according to the formula And the formula Determine Among them, t2 is 40, T c Take 1073, T0 takes 330, c takes 20; S205, according to the formula and formula Determine 4. The method for determining the sintering finish line position according to claim 1, characterized in that: The volume of the fuel gas blown into the sintering material surface is at most 0.8% of the volume of the air entering the sintering material surface.

5. The method for determining the sintering finish line position according to claim 1, characterized in that: The step S2 further includes the following steps: When the calculated sintering finish line position is not within the preset range, a warning instruction is sent to the target object.

6. A system for determining the position of a sintering finish line, characterized in that: It includes a sintering machine body, a gas injection device and a control system. The sintering machine body includes a material distribution area, an ignition furnace area and a holding furnace area. A gas injection area is provided downstream of the holding furnace area. The gas injection device is provided in the gas injection area. The gas injection device comprises a gas injection main pipe and a plurality of gas injection branch pipes arranged in parallel along the width direction of the sintering machine trolley; the gas injection main pipe is provided with the gas regulating valve; each of the gas injection branch pipes is connected to the gas injection main pipe, and a plurality of fuel nozzles for injecting gas toward the top surface of the sintering material layer are installed at the bottom of each gas injection branch pipe; The gas blowing device is connected to the control system, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method for determining the sintering finish line position as described in any one of claims 1 to 5 are implemented.

7. The sintering endpoint adjustment system according to claim 6, characterized in that: The plurality of gas injection branch pipes are evenly arranged along the width direction of the sintering machine trolley; the plurality of fuel nozzles of each gas injection branch pipe are evenly arranged along the length direction of the gas injection branch pipe.

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