Flue gas temperature detection-based sintering finish line adjusting method and system beneficial to carbon reduction

Abstract

The invention provides a sintering finish line adjusting method and system beneficial to carbon reduction based on flue gas temperature detection, and the method comprises the steps: obtaining a current sintering state, judging whether the current sintering state is an abnormal state or not, judging whether a gas adjusting valve is in an open state or not when the current sintering state is the abnormal state, and enabling the gas adjusting valve to be in a closed state when the gas adjusting valve is in the open state. Determining the fuel gas injection flow in the current state, determining a material layer thickness calculation value corresponding to the condition that the actual sintering finish line is adjusted to the expected sintering finish line in the current state according to the expected sintering finish line and a pre-established material thickness position algorithm model, and when the material layer thickness calculation value is within the effective material thickness adjustment range, adjusting the actual sintering finish line to the material layer thickness calculation value. And the current fuel gas injection flow is kept unchanged, and the thickness of the material layer is adjusted to the calculated value of the thickness of the material layer. By adopting the mode of combining fuel gas injection and material layer thickness adjustment, the stability and energy-saving and emission-reducing effects of sintering machine equipment are considered 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 is closely related to the sintering quality, output and cost. The sintering end point can indicate the end point where the material layer on the sintering trolley is calcined, that is, the sintering end position.

[0003] In the prior art, the technologies for regulating the sintering endpoint position can be divided into three categories: one 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); the third is to control the sintering endpoint by controlling the thickness of the sintering material layer. The existing methods for regulating the sintering endpoint 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 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.

[0004] In addition, some sintering plants in China have begun to use gas injection technology, that is, injecting gas during the sintering process to replace carbon in the sintering process. Obviously, after the gas participates in the sintering process, it will affect the vertical combustion speed, thereby affecting the sintering end point position, but the prior art currently does not have a control method to adjust the sintering end point by adjusting the gas, especially there is no specific adjustment method. Secondly, the fuel added during the sintering process provides heat for the sintering process. At present, the fuel is mainly coke powder and coal powder, and the mass ratio of the sintering fuel is about 4%. A large amount of CO2 is generated during the combustion process.

[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 saving 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 an abnormal state;

[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, according to the expected sintering end line and the pre-established material thickness position algorithm model, determining that the actual sintering end line in the current state is adjusted to the material layer thickness calculation value corresponding to the expected 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 fuel 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 value fitting curve within the first preset time period, and taking an average value of the gas injection flow rate value 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 comprises the steps of:

[0017] S11, obtaining the wind box flue gas temperature obtained by each temperature measuring unit; wherein each sintering wind box is equipped with a temperature measuring unit for detecting the wind box flue gas temperature passing through the sintering material, and the multiple temperature measuring units in the same sintering wind box 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 fume fitting curve has a curve inflection point, and when the sintering bellows fume 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 the lateral distance between the actual sintering end line and the expected sintering end line, and judging whether the lateral distance is greater than a preset threshold value, and when the lateral distance is greater than the preset threshold value, judging that the current sintering state is an over-sintering 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 gas injection flow rate in the current state is within the effective flow rate adjustment range, adjust the current gas injection flow rate according to the preset flow rate 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 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 speed of the sintering trolley, 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 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.

[0032] Preferably, each of the temperature measuring units is a multi-point thermocouple, the 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, the protective sleeve being installed on the sintering bellows along the width direction of the sintering trolley;

[0033] Wherein, the arithmetic average of the temperatures detected by the multiple thermocouples of the temperature measuring unit is taken as the wind box flue gas temperature of the temperature measuring unit.

[0034] The present invention also provides a sintering end-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, 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:

[0035] 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 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;

[0036] The sintering machine body further comprises a plurality of sintering bellows located directly below the sintering trolley, each sintering bellows is 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 executable 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 are implemented as described above.

[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 an abnormal state. When the current sintering state is an abnormal state, it determines whether the gas regulating valve is in an open state. When the gas regulating valve is in an open state, it determines the gas injection flow rate in the current state. 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 adjusted to the material layer thickness calculation value corresponding to the expected sintering end line. When the material layer thickness calculation 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 material layer thickness calculation value. 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 by adopting a combination of gas injection and material layer thickness adjustment. Specifically, when the gas injection flow rate is within the effective flow rate adjustment 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 sintering 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 adjustment range, the gas injection flow rate is maintained unchanged and the material layer thickness is adjusted to achieve a method of minimizing equipment fluctuations and achieving 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 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.

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

[0042] Figure 2 It is a schematic diagram of the sintered ore formation process in the prior art;

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

[0044] Figure 4 The second schematic cross-sectional view of the sintering ore 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 A schematic diagram of the formation of gas injection sintered ore in one embodiment of the present invention;

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

[0049] Fig. 9 It is a top view of a schematic diagram of the overall structure of a temperature measuring unit in one embodiment of the present invention;

[0050] Fig.10 It is a schematic diagram of a flow chart in one 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 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 used to limit the present invention.

[0053] 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.

[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 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 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.

[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 in the figure: 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 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 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 the finished ore bin after screening and granulation. Among them, the oxygen required for the sintering process is provided by the main exhaust fan. There are multiple vertically arranged bellows under the sintering trolley. Under the bellows is a horizontally placed large flue (or flue). The large flue 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.

[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, with the movement of the sintering 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 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 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 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.

[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, 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

[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 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.

[0061] like Figure 2 As shown in the figure, within 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 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.

[0066] Please refer to Figure 5-9Through 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.

[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 and is higher than the gas combustion point, the gas is ignited to form 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 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;

[0070] 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.

[0071] Please refer again to the attached Figure 5-9The present invention also provides a sintering end-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, 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:

[0072] 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 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;

[0073] The sintering machine body further comprises a plurality of sintering bellows located directly below the sintering trolley, each sintering bellows is 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 executable 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 are implemented as described below.

[0075] 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.

[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 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.

[0078] Please see attached Fig.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 an abnormal state;

[0080] S2, when the current sintering state is abnormal, determine whether the gas regulating valve is in the open state, and 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 sintering end line is preferably adjusted by adjusting the gas injection flow rate (according to a preset step length / increment and other adjustment methods). Specifically, as a preferred implementation, the steps S2 and S3 also include the following steps:

[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 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 adjustment range, enter step S3.

[0082] It is worth noting that the present 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 preferentially, 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 adopted flow regulation method cannot achieve the expected regulation effect. At this time, step S3 is entered to enter the step of adjusting the material layer thickness for adjustment.

[0083] It can be known that 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 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, determine the actual sintering end line in the current state to adjust 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. Adjust the machine speed in the current state to this value, and 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 fuel 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 the sintering trolley, if the material layer thickness is too low, even if the position of the sintering end point can be adjusted to a certain extent, it will lead to a significant decrease in production capacity. Similarly, the height of the sintering trolley's railing 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 steps of: S21, when the gas regulating valve is in the open state, obtaining the real-time value of the gas injection flow rate within the first preset time period after the current moment; S22, determining the gas injection flow rate value fitting curve within the first preset time period, and taking the average value of the gas injection flow rate value fitting curve 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, the step S1 specifically includes the following steps:

[0091] S11, obtaining the wind box flue gas temperature obtained by each temperature measuring unit; wherein each sintering wind box is equipped with a temperature measuring unit for detecting the wind box flue gas temperature passing through the sintering material, and the multiple temperature measuring units in the same sintering wind box 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 fume fitting curve has a curve inflection point, and when the sintering bellows fume 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). 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 the art 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 finish 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 the lateral distance between the actual sintering end line and the expected sintering end line, and judging whether the lateral distance is greater than a preset threshold value, and when the lateral distance is greater than the preset threshold value, judging that the current sintering state is an over-sintering 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 speed of the sintering trolley, 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 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.

[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, 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:

[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 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;

[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, unit 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, 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;

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

[0114] 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;

[0115] 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;

[0116] Formula 6a can be derived

[0117]

[0118] T2: Initial material temperature; 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 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:

[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 get:

[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 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.

[0128] 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:

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

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

[0132]

[0133] 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:

[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 get:

[0142]

[0143] Right now

[0144]

[0145] Substituting formula 12 into formula 10, we get:

[0146]

[0147] Substituting Formula 15 into Formula 3, we get:

[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 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 / Nm 3 ;

[0153] When the gas injection flow rate is 0Nm 3 / s, we can calculate:

[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 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;

[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 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 formula 16 is accurate.

[0157] As another example, when the gas injection flow rate is 0.006 Nm 3 / s, we can calculate:

[0158]

[0159] As another example, when the gas injection flow rate is 0.005 Nm 3 / s, we can calculate:

[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 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 mean 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 so as 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 a plurality of thermocouples installed in the protective sleeve. The thermocouple can accurately obtain the temperature of the location, and the protective sleeve is installed 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 the multiple thermocouples of the same temperature measuring unit, the obtained temperature value is used as 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 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 sintering end point adjustment method based on flue gas temperature abnormality to facilitate carbon reduction, characterized in that: Includes steps: S1, obtaining the current sintering state and determining whether the current sintering state is an abnormal state; 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, according to the expected sintering end line and the pre-established material thickness position algorithm model, determining that the actual sintering end line in the current state is adjusted to the material layer thickness calculation value corresponding to the expected 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, the current fuel gas injection flow rate is maintained unchanged, and the material layer thickness is adjusted to the calculated value of the material layer thickness.

2. The sintering end point adjustment method based on abnormal flue gas temperature to facilitate carbon reduction according to claim 1 is 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 value fitting curve within the first preset time period, and taking an average value of the gas injection flow rate value fitting curve as the gas injection flow rate in the current state.

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

4. The sintering end point adjustment method based on abnormal flue gas temperature to facilitate carbon reduction according to claim 1, characterized in that: The step S1 specifically includes the following steps: S11, obtaining the wind box flue gas temperature obtained by each temperature measuring unit; wherein each sintering wind box is equipped with a temperature measuring unit for detecting the wind box flue gas temperature passing through the sintering material, and the multiple temperature measuring units in the same sintering wind box 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 fume fitting curve has a curve inflection point, and when the sintering bellows fume 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 abnormal flue gas temperature 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 finish 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 the lateral distance between the actual sintering end line and the expected sintering end line, and judging whether the lateral distance is greater than a preset threshold value, and when the lateral distance is greater than the preset threshold value, judging that the current sintering state is an over-sintering 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 abnormal flue gas temperature to facilitate carbon reduction according to claim 5 is characterized in that: The 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 gas injection flow rate in the current state is within the effective flow adjustment range, adjusting the current gas injection flow rate according to the preset flow 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 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 rate adjustment range, enter step S3.

7. The sintering end point adjustment method based on abnormal flue gas temperature 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 abnormal flue gas temperature to facilitate carbon reduction according to claim 1, characterized in that: 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; 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, 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.

9. The sintering end point adjustment method based on abnormal flue gas temperature to facilitate carbon reduction according to claim 4, characterized in that: Each of the temperature measuring units is a multi-point thermocouple, and the multi-point thermocouple 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 multiple thermocouples of the temperature measuring unit is taken as the wind box flue gas temperature of the temperature measuring unit.

10. A sintering end-line adjustment system based on flue gas temperature detection to facilitate carbon reduction, 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 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 sintering machine body further comprises a plurality of sintering bellows located directly below the sintering trolley, each sintering bellows is 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 executable on the processor. When the processor executes the computer program, the steps of the sintering finish line adjustment method for carbon reduction based on abnormal flue gas temperature as described in any one of claims 1 to 9 are implemented.

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