Sintering end-line adjustment method and system based on flue gas temperature detection for carbon reduction

Abstract

The present invention provides a sintering end-line adjustment method and system based on flue gas temperature detection that is beneficial to carbon reduction. The method obtains the current sintering state and determines whether the current sintering state is abnormal. When the current sintering state is abnormal, it determines whether the gas regulating valve is in the open state. When the gas regulating valve is in the open state, it determines the gas injection flow rate in the current state. According to the expected sintering end-line and a pre-established material thickness position algorithm model, the actual sintering end-line in the current state is adjusted to the calculated material layer thickness value corresponding to the expected sintering end-line. When the calculated material layer thickness value is within the effective material thickness adjustment range, the current gas injection flow rate is maintained unchanged, and the material layer thickness is adjusted to the calculated material layer thickness value. By combining gas injection and material layer thickness adjustment, the present application takes into account the stability of the sintering machine equipment and the energy saving and emission reduction effects as much as possible.

Description

Technical Field

[0001] The present invention relates to the technical field of sintering, and in particular to a sintering end-line adjustment method and system based on flue gas temperature detection for carbon reduction. Background Art

[0002] 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 trolley is sintered, that is, the sintering end position.

[0003] In the existing technology, the technology for controlling the sintering endpoint can be divided into three categories: the first is to control the sintering endpoint by controlling the sintering trolley speed; the second is to control the sintering endpoint by controlling the sintering main exhaust fan system (negative pressure, air volume); and the third is to control the sintering end point by controlling the thickness of the sintering material layer. The existing methods of adjusting the sintering end point are 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 frequently adjusted, it will cause fluctuations in output / capacity. If the fan air volume is frequently adjusted, it will also cause the equipment to be in an unstable working state, increasing equipment wear and energy consumption.

[0004] Furthermore, some sintering plants in China are beginning to utilize gas injection technology, which involves injecting gas during the sintering process, replacing carbon with gas. While this gas's presence in the sintering process clearly affects the vertical combustion velocity and, consequently, the sintering endpoint, existing technologies currently lack a control method for adjusting the sintering endpoint by regulating the gas, particularly a specific method. Furthermore, the fuel added during the sintering process provides heat. Currently, the fuel mix primarily consists of coke pulverized coal and pulverized coal, with a mass ratio of approximately 4%. This combustion process produces significant amounts of CO2.

[0005] In view of this, it is necessary to propose a sintering end-line adjustment method and system based on flue gas temperature detection to facilitate carbon reduction in order 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 sintering end point adjustment method and system based on flue gas temperature detection to facilitate carbon reduction, so as to solve the technical problem of how to balance equipment stability and energy conservation and emission reduction during the sintering end point adjustment process.

[0007] To achieve the above object, the present invention provides a sintering end point adjustment method based on flue gas temperature detection to facilitate carbon reduction, comprising the steps of:

[0008] S1, obtaining the current sintering state and determining whether the current sintering state is abnormal;

[0009] S2, when the current sintering state is an abnormal state, determining whether the gas regulating valve is in an open state, and when the gas regulating valve is in an open state, determining the gas injection flow rate in the current state;

[0010] S3, determining the actual sintering end line in the current state according to the desired sintering end line and a pre-established material thickness position algorithm model, and adjusting the actual sintering end line to the calculated value of the material layer thickness corresponding to the desired sintering end line; wherein the material thickness position algorithm model includes a mapping relationship between the material layer thickness and the sintering end line;

[0011] S4, when the calculated value of the material layer thickness is within the effective material thickness adjustment range, the current gas injection flow rate is maintained unchanged, and the material layer thickness is adjusted to the calculated value of the material layer thickness.

[0012] Preferably, the step S2 of "determining the gas injection flow rate in the current state" specifically includes the following steps:

[0013] S21, when the gas regulating valve is in an open state, obtaining a real-time value of the gas injection flow rate within a first preset time period starting from the current moment;

[0014] S22: determining a gas injection flow rate fitting curve within the first preset time period, and taking an average value of the gas injection flow rate fitting curve as the gas injection flow rate in the current state.

[0015] Preferably, the first preset time length is set to 5s.

[0016] Preferably, the step S1 specifically includes the steps of:

[0017] S11, obtaining the windbox flue gas temperature obtained by each temperature measuring unit; wherein each sintering windbox is equipped with a temperature measuring unit for detecting the temperature of the windbox flue gas passing through the sintering material, and multiple temperature measuring units in the same sintering windbox are arranged at intervals along the length direction of the sintering trolley;

[0018] S12, performing temperature curve fitting on the wind box flue gas temperatures obtained by all temperature measuring units in sequence from the sintering machine head wheel to the sintering machine tail wheel to obtain a sintering wind box flue gas fitting curve;

[0019] S13, judging whether the sintering bellows flue gas fitting curve has a curve inflection point; when the sintering bellows flue gas fitting curve has a curve inflection point, obtaining an actual sintering end line in the current state according to the curve inflection point, and judging whether the current sintering state is an abnormal state according to the actual sintering end line.

[0020] Preferably, the step S13 of “determining whether the current sintering state is abnormal according to the actual sintering finish line” specifically includes the following steps:

[0021] S131, determining whether the actual sintering end line lags behind the expected sintering end line along the running direction of the sintering machine;

[0022] S132, when the actual sintering end line lags behind the expected sintering end line along the running direction of the sintering machine, determining a transverse distance between the actual sintering end line and the expected sintering end line, and judging whether the transverse distance is greater than a preset threshold value, and when the transverse distance is greater than the preset threshold value, judging that the current sintering state is an over-sintering state;

[0023] S133: When the actual sintering end line is ahead of the expected sintering end line along the running direction of the sintering machine, it is determined that the current sintering state is a normal sintering state.

[0024] Preferably, the steps S2 and S3 further include the following steps:

[0025] S21, determining whether the gas injection flow rate in the current state is within the effective flow rate adjustment range;

[0026] S22, when the current gas injection flow rate is within the effective flow rate adjustment range, adjust the current gas injection flow rate according to the preset flow rate step; wait for a second preset time, and then return to step S1; wherein the second preset time is determined by the formula ST = S1 / SV, wherein S1 is the distance from the gas injection starting point to the desired sintering end line, and SV is the moving speed of the sintering trolley;

[0027] S23: When the gas injection flow rate in the current state is not within the effective flow rate adjustment range, enter step S3.

[0028] Preferably, the effective material thickness adjustment range is set between 0.3m and 0.9m.

[0029] Preferably, the "material thickness position algorithm model" in step S3 is specifically:

[0030]

[0031] Among them, S is the sintering end line, H is the theoretical calculated value of the material layer thickness corresponding to the sintering end line S; 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 sintering trolley speed, c is the thickness of the solid combustion zone, k1 is the heat transfer coefficient, h is the gas combustion heat, t is the duration of gas blowing, m is the material amount per unit sintering machine, z is the material layer thickness below the gas combustion zone, and Cp is the average specific heat capacity of the sintering material.

[0032] Preferably, each of the temperature measuring units is a multi-point thermocouple, comprising a protective sleeve and a plurality of thermocouples installed in the protective sleeve and evenly arranged along the length direction of the protective sleeve, and the protective sleeve is installed on the sintering bellows along the width direction of the sintering trolley;

[0033] The arithmetic average of the temperatures detected by the multiple thermocouples of the temperature measuring unit is taken as the windbox flue gas temperature of the temperature measuring unit.

[0034] The present invention also provides a sintering finish line adjustment system based on flue gas temperature detection to facilitate carbon reduction, comprising a sintering machine body, a gas injection device and a control system. 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:

[0035] The gas injection device includes a gas injection main pipe and a plurality of gas injection branch pipes arranged in parallel along the width direction of the sintering trolley; the gas regulating valve is installed on the gas injection main pipe; each of the gas injection branch pipes is connected to the gas injection main pipe, and a plurality of burners for injecting gas toward the top surface of the sintering material layer are installed at the bottom of each gas injection branch pipe;

[0036] The sintering machine body further comprises a plurality of sintering bellows located directly below the sintering trolley, each sintering bellows being equipped with a temperature measuring unit for detecting the temperature of the bellows flue gas passing through the sintering material, and the plurality of temperature measuring units in the same sintering bellows are arranged at intervals along the length direction of the sintering trolley;

[0037] The gas injection device and the temperature measuring unit are both connected to the control system, which includes a memory, a processor, and a computer program stored in the memory and run on the processor. When the processor executes the computer program, it implements the steps of the above-mentioned sintering end line adjustment method based on flue gas temperature abnormality to facilitate carbon reduction.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The present invention provides a sintering end-line adjustment method and system based on flue gas temperature detection that is beneficial to carbon reduction. The method obtains the current sintering state and determines whether the current sintering state is abnormal. When the current sintering state is abnormal, it determines whether the gas regulating valve is in the open state. When the gas regulating valve is in the open state, it determines the gas injection flow rate in the current state. According to the expected sintering end-line and a pre-established material thickness position algorithm model, the actual sintering end-line in the current state is adjusted to the calculated material layer thickness value corresponding to the expected sintering end-line. When the calculated material layer thickness value is within the effective material thickness adjustment range, the current gas injection flow rate is maintained unchanged, and the material layer thickness is adjusted to the calculated material layer thickness value. By combining gas injection and material layer thickness adjustment, the present application takes into account the stability of the sintering machine equipment and the energy saving and emission reduction effects as much as possible. Specifically, when the gas injection flow rate is within the effective flow rate regulation range, the sintering finish line is adjusted by adjusting the gas injection flow rate. The gas injection uses coke oven gas and natural gas to be sprayed on the sintering material surface to form a gas fuel combustion zone, which provides heat for the sintering ore formation process, reduces the fuel ratio in the sintered ore, and can significantly reduce (more than 10%) CO2 emissions. When the gas injection flow rate in the current state is not within the effective flow rate regulation range, the gas injection flow rate is maintained unchanged and the material layer thickness is adjusted to achieve an adjustment method that minimizes equipment fluctuations and achieves emission reductions, thereby taking into account the stability of the sintering machine equipment and the energy-saving and emission reduction effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0041] Figure 1 This is a process flow chart of a sintering system in the prior art;

[0042] Figure 2 Schematic diagram of the sintered ore formation process in the prior art;

[0043] Figure 3 This is one of the cross-sectional schematic diagrams of the sinter formation process in the prior art;

[0044] Figure 4 This is the second cross-sectional schematic diagram of the sinter formation process in the prior art;

[0045] Figure 5 A side view of a schematic diagram of the overall structure of an embodiment of the present invention;

[0046] Figure 6A top view of a schematic diagram of the overall structure of an embodiment of the present invention;

[0047] Figure 7 Schematic diagram of formation of sintered ore by gas injection in one embodiment of the present invention;

[0048] Figure 8 A side view of a schematic diagram of the overall structure of a temperature measuring unit in one embodiment of the present invention;

[0049] Figure 9 A top view of a schematic diagram of the overall structure of a temperature measuring unit in one embodiment of the present invention;

[0050] Figure 10 FIG. 1 is a flow chart of an embodiment of the present invention.

[0051] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0052] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0053] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0054] 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 various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0055] In addition, the descriptions of "first", "second", etc. in the present invention are for descriptive purposes only and should not 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" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0056] 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 trolley, a mixer, a main exhaust fan, an annular cooler and other equipment. Figure 1 As shown, various raw materials are proportioned in the batching chamber to form a mixture. The mixture enters the mixer for mixing and pelletizing, and then is evenly distributed on the sintering trolley by a circular roller feeder and a nine-roller distributor to form a sintering mixture layer. The ignition fan and the ignition pilot fan start the ignition furnace, which ignites the sintering mixture on the top layer of the sintering trolley. 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 cooled in an annular cooler. Finally, it is screened and sized before being sent to the blast furnace or finished ore bin. The oxygen required for the sintering process is provided by the main exhaust fan. Multiple vertically arranged bellows are installed below the sintering trolley. Below the bellows is a horizontally mounted large flue (or flue). The large flue is connected to the main exhaust fan. The negative pressure air generated by the main exhaust fan through the flue and bellows passes through the trolley, providing combustion air for the sintering process.

[0057] 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 trolley moves from the head to the tail of the sintering machine, and the movement speed of the sintering trolley is the sintering machine speed. When the combustion zone moves to the bottom of the sintering trolley mixture (the bottom material layer position), the corresponding position of the sintering trolley relative to the head of the sintering machine is the sintering end position. Figure 2 As shown in the figure, as the sintering trolley moves, the combustion zone gradually moves downward, and the mixture 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 trolley 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 them, the base material layer is a finished sintered ore of a certain particle size. Figure 4 As shown in the figure, when the combustion zone moves to the bed material layer, the materials in the sintering trolley have all been roasted into sintered ore. The corresponding position at this time 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 point where the bottom of the combustion zone just contacts the bed material layer. When the sintering end position is controlled at the second-to-last bellows or the first-to-last bellows, no raw meal is 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.

[0058] 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 in the figure, the speed at which the combustion zone moves downward is called the sintering speed, which is represented by LV and is in m / s. The thickness of the material layer on the sintering machine is represented by H and is in m. There is a base material under the sintering mixture, which is a finished sintered ore of a certain particle size. The thickness can be represented by PH and is in 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

[0059] ST = (H-PH) / LV Formula 1

[0060] 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 trolley, controlling the sintering end point at the last bellows or the penultimate 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 sintering material surface is ignited has an optimal value S0, and the position corresponding to S0 is the target sintering end position.

[0061] like Figure 2 As shown in the figure, during the sintering time ST, the relationship between the sintering trolley moving distance S (unit: m), the sintering trolley speed SV (unit: m / min), and the sintering time ST is shown in formula 2:

[0062] S=ST*SV Formula 2

[0063] Combining (1) and (2) we can get

[0064]

[0065] In summary, according to formula (3), it can be concluded that the existing technologies for adjusting the sintering endpoint can be divided into three categories: the existing methods for adjusting the sintering endpoint are relatively simple. The first is to adjust the sintering endpoint by controlling the sintering trolley speed SV; the second is to adjust the sintering speed LV and thus adjust the sintering endpoint by controlling the sintering main exhaust fan system (negative pressure, air volume); and the third is to adjust the sintering endpoint 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 will be in an unstable working state. If the material layer thickness is frequently adjusted, it will cause fluctuations in output / capacity. If the fan air volume is frequently adjusted, it will also cause the equipment to be in an unstable working state, increasing equipment wear and energy consumption.

[0066] Please refer to Figure 5-9Through the study of sintering technology, it was found that 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., the 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 along with the air. When the gas reaches the temperature area above the solid combustion zone where the temperature 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.

[0067] 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, which is higher than the gas combustion point, the gas is ignited, forming a gas combustion zone suspended above the solid combustion zone.

[0068] 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.

[0069] In actual applications, considering issues such as gas safety, the maximum volume fraction of gas injection is 0.8%, that is, the volume of gas blown into the sintering material surface is at most 0.8% of the volume of air entering the sintering material surface. Issues related to nozzle arrangement and sufficient mixing of gas and air have existing solutions and are beyond the scope of this case. The oxygen in the air consumed by the combustion of gas with a volume fraction below 0.8% has little effect on the combustion of solid fuel in the sintered ore. The volume fraction can be linearly converted to the flow rate of the regulating valve F1. For example, the volume fraction of the gas is 0.8% at the maximum flow rate L1, and 0.4% at 0.5 times L1.

[0070] It will 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 decrease 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.

[0071] Please refer again to the attached Figure 5-9The present invention also provides a sintering finish line adjustment system based on flue gas temperature detection to facilitate carbon reduction, comprising a sintering machine body, a gas injection device and a control system. 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:

[0072] The gas injection device includes a gas injection main pipe and a plurality of gas injection branch pipes arranged in parallel along the width direction of the sintering trolley; the gas regulating valve is installed on the gas injection main pipe; each of the gas injection branch pipes is connected to the gas injection main pipe, and a plurality of burners for injecting gas toward the top surface of the sintering material layer are installed at the bottom of each gas injection branch pipe;

[0073] The sintering machine body further comprises a plurality of sintering bellows located directly below the sintering trolley, each sintering bellows being equipped with a temperature measuring unit for detecting the temperature of the bellows flue gas passing through the sintering material, and the plurality of temperature measuring units in the same sintering bellows are arranged at intervals along the length direction of the sintering trolley;

[0074] The gas injection device and the temperature measuring unit are both connected to the control system, which includes a memory, a processor, and a computer program stored in the memory and run on the processor. When the processor executes the computer program, it implements the following steps of the sintering end line adjustment method based on flue gas temperature abnormality to facilitate carbon reduction.

[0075] Optionally, the gas blowing zone is set adjacent to the insulation furnace zone, and a gas blowing device is provided in the gas blowing zone. The gas blowing branch pipe is arranged opposite the trolley track and is used to blow gas to the trolley on the trolley track passing through the gas blowing zone. The gas blowing area is set to 15-20m along the length direction of the sintering machine body.

[0076] 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.

[0077] 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 uniformly arranging, the effect of the entire sintering end point controlled by gas injection is made more accurate (each partition can be adjusted by controlling it separately). In other embodiments, those skilled in the art can also adaptively adjust the spacing between the plurality of gas injection pipes, or adaptively adjust the spacing between the plurality of burner nozzles on each gas injection branch pipe. In addition, by uniformly arranging, it is convenient for each sub-partition (one gas injection branch pipe can be set to correspond to one sub-partition), and targeted adjustments can be made to the sub-partitions, thereby adjusting the uniformity of the sintered ore.

[0078] Please see the attached Figure 10 The present invention provides a sintering finish line adjustment method based on flue gas temperature abnormality, comprising the steps of:

[0079] S1, obtaining the current sintering state and determining whether the current sintering state is abnormal;

[0080] S2, when the current sintering state is abnormal, determine whether the gas regulating valve is in the open state. When the gas regulating valve is in the open state, determine the gas injection flow rate in the current state; specifically, the gas injection flow rate in the current state can be obtained by installing a flow meter on the gas injection main pipe. In the present application, a combination of gas injection and material layer thickness adjustment is adopted. Specifically, when the gas injection flow rate is within the effective flow adjustment range, the gas injection flow rate is preferably adjusted (according to a preset step size / increment adjustment method) to adjust the sintering end line. Specifically, as a preferred embodiment, the steps S2 and S3 are further included between:

[0081] S21, determine whether the gas injection flow rate in the current state is within the effective flow adjustment range; S22, when the gas injection flow rate in the current state is within the effective flow adjustment range, adjust the current gas injection flow rate according to the preset flow step; wait for the second preset time, and then return to step S1; wherein, the second preset time is determined by the formula ST=S1 / SV, wherein S1 is the distance from the starting point of the gas injection to the desired sintering end line, and SV is the moving speed of the sintering trolley; S23, when the gas injection flow rate in the current state is not within the effective flow adjustment range, enter step S3.

[0082] It is worth noting that this embodiment specifically provides limiting conditions for giving priority to flow regulation. Specifically, when the gas injection flow rate in the current state is within the effective flow regulation range, the gas injection flow rate can be adjusted first, and then the second preset time is waited for to determine whether the actual sintering end line after adjustment is within the tolerance range of the expected sintering end line. If so, it means that the method of giving priority to flow regulation of the sintering end line is effective in form. If not, it means that the flow regulation method adopted cannot achieve the expected regulation effect. At this time, step S3 is entered, and the step of adjusting the material layer thickness is entered.

[0083] It can be known that gas injection uses coke oven gas and natural gas to be injected on the sintering material surface to form a gas fuel combustion zone, which provides heat for the sintering ore formation process, reduces the fuel ratio in the sintering ore, and can significantly reduce (more than 10%) CO2 emissions. This application is to achieve an adjustment method that minimizes equipment fluctuations and achieves emission reductions, thereby taking into account the stability of the sintering machine equipment and the energy-saving and emission reduction effects.

[0084] S3, according to the expected sintering end line and the pre-established material thickness position algorithm model, the actual sintering end line in the current state is determined to be adjusted to the material layer thickness calculation value corresponding to the expected sintering end line; wherein, the material thickness position algorithm model includes the mapping relationship between the material layer thickness and the sintering end line; it is worth noting that the material thickness 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 pre-established material thickness position algorithm model includes the mapping relationship between the material layer thickness and the sintering end line, the corresponding material layer thickness calculation value can be calculated after knowing the expected sintering end line and the gas injection flow rate in the current state. By adjusting the machine speed in the current state to this value, the corresponding actual sintering end line can be adjusted to the expected sintering end line position.

[0085] S4, when the calculated value of the material layer thickness is within the effective material thickness adjustment range, the current gas injection flow rate is maintained unchanged, and the material layer thickness is adjusted to the calculated value of the material layer thickness.

[0086] It is understandable that the adjustment range of the material layer thickness is limited. For a sintering trolley, if the material layer thickness is too low, even if the sintering endpoint position can be adjusted to a certain extent, it will lead to a significant reduction in production capacity. Similarly, the height of the sintering trolley's sideboard is limited, so the effective material thickness adjustment range has an upper limit. As a preferred example, the effective material thickness adjustment range is set between 0.3m and 0.9m.

[0087] As a preferred embodiment of the present invention, the step S2 of "determining the gas injection flow rate in the current state" specifically includes the following steps: S21, when the gas regulating valve is in the open state, obtaining the real-time value of the gas injection flow rate within a first preset time period starting from the current moment; S22, determining a fitting curve of the gas injection flow rate values ​​within the first preset time period, and taking the average value of the fitting curve of the gas injection flow rate values ​​as the gas injection flow rate in the current state.

[0088] It can be understood that the average value obtained by the method provided in this embodiment is used as the gas injection flow rate in the current state, thereby reducing the error and influence caused by the fluctuation of the gas injection flow rate.

[0089] Preferably, the first preset time length is set to 5s. It is understandable that, in other embodiments, those skilled in the art may also set the first preset time length to other values, such as 8s.

[0090] As a preferred embodiment of the present invention, step S1 specifically includes the following steps:

[0091] S11, obtaining the windbox flue gas temperature obtained by each temperature measuring unit; wherein each sintering windbox is equipped with a temperature measuring unit for detecting the temperature of the windbox flue gas passing through the sintering material, and multiple temperature measuring units in the same sintering windbox are arranged at intervals along the length direction of the sintering trolley;

[0092] S12, performing temperature curve fitting on the wind box flue gas temperatures obtained by all temperature measuring units in sequence from the sintering machine head wheel to the sintering machine tail wheel to obtain a sintering wind box flue gas fitting curve;

[0093] S13, judging whether the sintering bellows flue gas fitting curve has a curve inflection point; when the sintering bellows flue gas fitting curve has a curve inflection point, obtaining an actual sintering end line in the current state according to the curve inflection point, and judging whether the current sintering state is an abnormal state according to the actual sintering end line.

[0094] It is worth noting that the maximum value of the bellows flue gas temperature (inflection point value of the curve) can reflect the position of the current combustion zone (i.e., the sintering end point position), and the temperature measuring unit corresponding to the maximum value of the bellows flue gas temperature corresponds to the sintering end point position. When the actual sintering end point line lags behind the expected sintering end point line, it means that the sintering end point line in this state may be close to the expected sintering end point line (which is considered to be the ideal sintering state in this field), or it may be far away from the expected sintering end point line. This state indicates that the sintering area is not fully utilized, and the production capacity and output are affected, which requires further subsequent judgment and analysis.

[0095] In addition, when the actual sintering finish line is ahead of the expected sintering finish line, it means that the actual sintering finish line is between the expected sintering finish line (generally considered in this field to correspond to the position of the penultimate bellows or the penultimate bellows) and the tail of the last sintering bellows. At this time, it can be determined that the actual sintering finish line in the current state is within the tolerance range of the expected sintering finish line, and the current state can be maintained to continue production.

[0096] As a preferred embodiment, the step S13 of “determining whether the current sintering state is abnormal according to the actual sintering end line” specifically includes the following steps:

[0097] S131, determining whether the actual sintering end line lags behind the expected sintering end line along the running direction of the sintering machine;

[0098] S132, when the actual sintering end line lags behind the expected sintering end line along the running direction of the sintering machine, determining a transverse distance between the actual sintering end line and the expected sintering end line, and judging whether the transverse distance is greater than a preset threshold value, and when the transverse distance is greater than the preset threshold value, judging that the current sintering state is an over-sintering state;

[0099] S133: When the actual sintering end line is ahead of the expected sintering end line along the running direction of the sintering machine, it is determined that the current sintering state is a normal sintering state.

[0100] Furthermore, the “material thickness position algorithm model” in step S3 is specifically:

[0101]

[0102] Among them, S is the sintering end line, H is the theoretical calculated value of the material layer thickness corresponding to the sintering end line S; 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 sintering trolley speed, c is the thickness of the solid combustion zone, k1 is the heat transfer coefficient, h is the gas combustion heat, t is the duration of gas blowing, m is the material amount per unit sintering machine, z is the material layer thickness below the gas combustion zone, and Cp is the average specific heat capacity of the sintering material.

[0103] Specifically, in order to further illustrate the material thickness position algorithm model and facilitate those skilled in the art to understand the material thickness position algorithm model of the present application, the derivation process of the model is now specifically described:

[0104] 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:

[0105] P1=Q*h Formula 4

[0106] 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 ;

[0107] 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, causing its initial temperature to increase by ΔT compared to 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 transfer downward and add to the material below the solid combustion zone; among them, the initial temperature increase ΔT of the material near the solid combustion zone to be ignited can be calculated by Formula 5 and Formula 6:

[0108] 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;

[0109] 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 carried 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 sintered ore layer, the gas combustion zone, the sintered ore layer between the gas-solid combustion zone, the solid combustion zone, and the mixed material layer; the flue gas is heated by the sintered 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. As the gas combustion zone and the solid combustion zone gradually move downward, the heated lower layer materials gradually decrease.

[0110] 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; where P2 is the heat directly transferred from the gas combustion to the material, in units of W;

[0111] 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;

[0112] Where: P2: heat directly transferred to the material by gas combustion, unit: W; k1: transfer coefficient, dimensionless; (slightly different for different sintering machines, but can be considered a constant under stable operating conditions of the same sintering machine); ΔT: initial temperature increase of the solid combustion zone material caused by gas fuel, unit: K; m: material quantity 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 the sintering material, unit: J / (kg*K); t: duration of gas injection, unit: s;

[0113] The specific derivation process of Formula 6 is as follows:

[0114] From the derivation of formula 5, we can know that the heat of P2 is transferred to the material layer below the combustion zone. The thickness of the material layer below the combustion zone is Z; the total thickness of the material layer is H;

[0115] During the gas injection period, the material above the gas combustion zone will not be heated by the heat provided by the gas combustion zone, and the amount of heated material below the gas combustion zone is m*(z / H), and the duration is t;

[0116] Formula 6a can be derived

[0117]

[0118] T2: Initial temperature of the material; T1: Temperature of the material after being heated by the gas combustion zone

[0119] ΔT=T1-T2

[0120] Substituting formula 4 and 6a into formula 6, we can obtain:

[0121]

[0122] In formula 7, the transfer coefficient k1, the combustion heat of gas fuel h, and the average specific heat capacity Cp of the sintering material 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 z of the material layer under the gas combustion zone gradually decreases as the sintering machine moves forward. In the gas injection range, the average value can be 0.75*H~0.85*H. The coefficient K1 can be obtained as shown in formula 8:

[0123] According to the formula P1=Q*h, the formula P2=k1*P1 and the formula Determine

[0124] Substituting Formula 8 into Formula 7, we can obtain:

[0125] ΔT=K1*Q Formula 9

[0126] 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.

[0127] It's important to note that the combustion of sintered solid fuels primarily involves four processes: 1. Preheating of charcoal powder; 2. Volatile analysis; 3. Combustion of volatiles; and 4. Residual carbon combustion. The latter three processes, involving complex coupled heat and mass transfer and chemical reactions, can be collectively referred to as the full combustion process. The total solid fuel combustion time, tt, can be roughly considered the sum of the time t1 required for the charcoal powder to reach its ignition point due to residual heat, and the time t2 required for the charcoal powder to fully burn. The effect of gas injection on the solid fuel combustion rate is primarily manifested in increasing the initial reactant temperature, thereby reducing the preheating time t1. Once solid fuel combustion begins, the full combustion time t2 remains unchanged.

[0128] Before and after gas injection, the heat transfer coefficient between the sintering material bed and the high-temperature gas can be approximately considered unchanged. Therefore, the preheating time t1 can be calculated by formula 10:

[0129]

[0130] 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: heating rate of material layer, unit K / s;

[0131] Therefore, the total time tt of solid fuel combustion can be calculated using Equation 11:

[0132]

[0133] Obviously, the fuel thickness in the solid combustion zone divided by the total time of solid fuel combustion is the combustion velocity of the solid combustion zone moving downward, and the formula 12 can be obtained:

[0134]

[0135] Substituting Formula 9 into Formula 11, we get:

[0136]

[0137] Typical values ​​of relevant parameters are shown in Table 1

[0138] Table 1: Typical values ​​of relevant parameters

[0139]

[0140]

[0141] Substituting typical values ​​into formula 13, we can obtain:

[0142]

[0143] Right now

[0144]

[0145] Substituting Equation 12 into Equation 10, we obtain:

[0146]

[0147] Substituting Equation 15 into Equation 3, we obtain:

[0148]

[0149] According to formula 16, the material thickness position algorithm model of this application is obtained:

[0150]

[0151] Here are some examples:

[0152] The thickness of the material layer of a certain sintering machine is H = 0.7m, the thickness of the bottom material layer is PH = 0.1m, the material amount of the unit sintering machine is 250kg, the speed of the sintering trolley is SV = 0.035m / s, the thickness of the solid combustion zone is c = 0.03m, the thickness of the bottom material layer is PH = 0.1m, the average specific heat capacity of the sintering material Cp = 1600J / (kg*K), the gas injection time is 500s, the transfer coefficient k1 = 0.35, and the unit gas combustion heat h = 30000000J / Nm 3 ;

[0153] When the gas injection flow rate is 0Nm 3 / s can be calculated as follows:

[0154]

[0155] The total length of the sintering machine is 90 meters, the length of a single wind box is 4 meters, the length from the distribution position 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;

[0156] 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 25 mm and the material layer is considered to be 800 mm, the calculated position is 74.06 m. This matches the actual situation and shows that the above formula 16 is accurate.

[0157] As another example, when the gas injection flow rate is 0.006 Nm 3 / s can be calculated as follows:

[0158]

[0159] As another example, when the gas injection flow rate is 0.005 Nm 3 / s can be calculated as follows:

[0160]

[0161] The accuracy of Formula 16 can be verified through the above specific examples, which also shows that the material thickness position algorithm model of the present application has high accuracy and can be used to guide the adjustment of the material layer thickness.

[0162] As a preferred embodiment, each of the temperature measuring units is a multi-point thermocouple, which includes a protective sleeve and a plurality of thermocouples installed in the protective sleeve and evenly arranged along the length direction of the protective sleeve, and the protective sleeve is installed on the sintering bellows along the width direction of the sintering trolley; wherein the arithmetic average of the temperatures detected by the plurality of thermocouples of the temperature measuring unit is taken as the bellows flue gas temperature of the temperature measuring unit.

[0163] It is worth noting that in order to more accurately reflect the flue gas temperature of the sintering bellows and to better determine the sintering finish line, the temperature measuring unit in this embodiment adopts a multi-point thermocouple. Those skilled in the art may understand that the multi-point thermocouple is a temperature measuring element commonly used in industrial scenarios, including a protective sleeve and multiple thermocouples installed in the protective sleeve. The thermocouple can accurately obtain the temperature of the location. By installing the protective sleeve on the sintering bellows along the width direction of the sintering machine trolley, that is, one temperature measuring unit can obtain the temperature distribution of a sintering cross section. After taking the arithmetic average of the temperature values ​​of multiple thermocouples of the same temperature measuring unit, the temperature value obtained is the bellows flue gas temperature obtained by the temperature measuring unit. It can be understood that the bellows flue gas temperature obtained by taking the average value can accurately reflect the flue gas temperature corresponding to the sintering bellows, thereby accurately obtaining the corresponding sintering finish line.

[0164] 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 description 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 sintering end point adjustment method based on flue gas temperature abnormality to facilitate carbon reduction, characterized in that: Including steps: S1, obtaining the current sintering state and determining whether the current sintering state is abnormal; S2, when the current sintering state is an abnormal state, determining whether the gas regulating valve is in an open state, and when the gas regulating valve is in an open state, determining the gas injection flow rate in the current state; S3, determining the actual sintering end line in the current state according to the desired sintering end line and a pre-established material thickness position algorithm model, and adjusting the actual sintering end line to the calculated value of the material layer thickness corresponding to the desired sintering end line; wherein the material thickness position algorithm model includes a mapping relationship between the material layer thickness and the sintering end line; S4, when the calculated value of the material layer thickness is within the effective material thickness adjustment range, maintaining the current gas injection flow rate unchanged, and adjusting the material layer thickness to the calculated value of the material layer thickness; The material thickness position algorithm model in step S3 is specifically: ； Among them, S is the sintering end line, H is the theoretical calculated value of the material layer thickness corresponding to the sintering end line S; PH is the thickness of the base material layer, c is the thickness of the solid combustion zone, k1 is the heat transfer coefficient, h is the gas combustion heat, t is the duration of gas injection, m is the material amount per unit sintering machine, z is the material layer thickness below the gas combustion zone, Cp is the average specific heat capacity of the sintering material, and Q is the gas fuel flow rate.

2. The sintering end point adjustment method based on flue gas temperature abnormality to facilitate carbon reduction according to claim 1, characterized in that: The step S2 of "determining the gas injection flow rate in the current state" specifically includes the following steps: S21, when the gas regulating valve is in an open state, obtaining a real-time value of the gas injection flow rate within a first preset time period starting from the current moment; S22: determining a gas injection flow rate fitting curve within the first preset time period, and taking an average value of the gas injection flow rate fitting curve as the gas injection flow rate in the current state.

3. The sintering end point adjustment method based on flue gas temperature abnormality to facilitate carbon reduction according to claim 2, characterized in that: The first preset time length is set to 5s.

4. The sintering end point adjustment method based on flue gas temperature abnormality to facilitate carbon reduction according to claim 1, characterized in that: The step S1 specifically includes the following steps: S11, obtaining the windbox flue gas temperature obtained by each temperature measuring unit; wherein each sintering windbox is equipped with a temperature measuring unit for detecting the temperature of the windbox flue gas passing through the sintering material, and multiple temperature measuring units in the same sintering windbox are arranged at intervals along the length direction of the sintering trolley; S12, performing temperature curve fitting on the wind box flue gas temperatures obtained by all temperature measuring units in sequence from the sintering machine head wheel to the sintering machine tail wheel to obtain a sintering wind box flue gas fitting curve; S13, judging whether the sintering bellows flue gas fitting curve has a curve inflection point; when the sintering bellows flue gas fitting curve has a curve inflection point, obtaining an actual sintering end line in the current state according to the curve inflection point, and judging whether the current sintering state is an abnormal state according to the actual sintering end line.

5. The sintering end point adjustment method based on flue gas temperature abnormality to facilitate carbon reduction according to claim 4 is characterized in that: The step S13 of "determining whether the current sintering state is abnormal according to the actual sintering end line" specifically includes step: S131, determining whether the actual sintering end line lags behind the expected sintering end line along the running direction of the sintering machine; S132, when the actual sintering end line lags behind the expected sintering end line along the running direction of the sintering machine, determining a transverse distance between the actual sintering end line and the expected sintering end line, and judging whether the transverse distance is greater than a preset threshold value, and when the transverse distance is greater than the preset threshold value, judging that the current sintering state is an over-sintering state; S133: When the actual sintering end line is ahead of the expected sintering end line along the running direction of the sintering machine, it is determined that the current sintering state is a normal sintering state.

6. The sintering end point adjustment method based on flue gas temperature abnormality to facilitate carbon reduction according to claim 5, characterized in that: The steps between steps S2 and S3 also include the following steps: S21, determining whether the gas injection flow rate in the current state is within the effective flow rate adjustment range; S22, when the current gas injection flow rate is within the effective flow rate adjustment range, adjusting the current gas injection flow rate according to the preset flow rate step; Wait for a second preset time, and then return to step S1; wherein the second preset time is determined by the formula ST=S1 / SV, wherein S1 is the distance from the gas injection starting point to the desired sintering end line, and SV is the moving speed of the sintering trolley; S23: When the gas injection flow rate in the current state is not within the effective flow rate adjustment range, enter step S3.

7. The sintering end point adjustment method based on flue gas temperature abnormality to facilitate carbon reduction according to claim 1, characterized in that: The effective material thickness adjustment range is set between 0.3m and 0.9m.

8. The sintering end point adjustment method based on flue gas temperature abnormality to facilitate carbon reduction according to claim 4, characterized in that: Each of the temperature measuring units is a multi-point thermocouple, comprising a protective sleeve and a plurality of thermocouples installed in the protective sleeve and evenly arranged along the length direction of the protective sleeve, wherein the protective sleeve is installed on the sintering bellows along the width direction of the sintering trolley; The arithmetic average of the temperatures detected by the multiple thermocouples of the temperature measuring unit is taken as the windbox flue gas temperature of the temperature measuring unit.

9. A sintering finish line adjustment system based on flue gas temperature detection to facilitate carbon reduction, characterized in that: The sintering machine comprises a main body, a gas injection device and a control system. The main 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. The gas injection device is provided in the gas injection area, wherein: The gas injection device includes a gas injection main pipe and a plurality of gas injection branch pipes arranged in parallel along the width direction of the sintering trolley; the gas regulating valve is installed on the gas injection main pipe; each of the gas injection branch pipes is connected to the gas injection main pipe, and a plurality of burners for injecting gas toward the top surface of the sintering material layer are installed at the bottom of each gas injection branch pipe; The sintering machine body further comprises a plurality of sintering bellows located directly below the sintering trolley, each sintering bellows being equipped with a temperature measuring unit for detecting the temperature of the bellows flue gas passing through the sintering material, and the plurality of temperature measuring units in the same sintering bellows are arranged at intervals along the length direction of the sintering trolley; The gas injection device and the temperature measuring unit are both connected to the control system, which includes a memory, a processor, and a computer program stored in the memory and run on the processor. When the processor executes the computer program, the steps of the sintering finish line adjustment method based on flue gas temperature abnormality to facilitate carbon reduction as described in any one of claims 1 to 8 are implemented.

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