A nitrogen-carbon double balance coupled blast furnace iron holding judgment method and system

Abstract

The application discloses a nitrogen-carbon double balance coupling-based blast furnace iron holding judgment method and system, and the method comprises the following steps: calculating the ton iron coal gas generation amount according to the carbon balance principle; calculating the total amount of coal gas generation in the blast furnace according to the nitrogen balance principle; in the third step, the total amount of coal gas generation and the ton iron coal gas generation amount are obtained, and the corresponding relationship between the total amount of coal gas generation and the unit molten iron coal gas consumption is utilized to calculate the pig iron production amount of the blast furnace hearth per minute; the blast furnace hearth iron tapping amount per minute is calculated, and is compared with the obtained pig iron production amount per minute, and the preliminary judgment of the blast furnace iron holding is carried out according to the comparison result; according to the preliminary judgment result, the final judgment of the blast furnace iron holding is carried out in combination with the abnormal working condition characteristics. The application has the beneficial effects that the total amount of blast furnace coal gas generation is calculated from the smelting material balance, the real-time pig iron generation rate of the blast furnace hearth is coupled and deduced, the judgment result is more accurate, and the indirect derived parameters such as the pressure difference are not relied on, and the judgment result is not interfered by the furnace temperature fluctuation, the abnormal material distribution and the short-term material collapse.

Description

Technical Field

[0001] This invention relates to the field of blast furnace ironmaking technology, specifically to a method and system for judging blast furnace bridging based on nitrogen-carbon dual-balance coupling. Background Technology

[0002] Blast furnace slag buildup is a typical severe furnace condition in ironmaking. Essentially, it occurs when the rate of molten slag and iron formation in the hearth exceeds the actual iron and slag tapping rate, causing a continuous rise in slag and iron levels, the rise of dead coke columns, and a continuous reduction in the effective permeable space of the hearth. Once slag buildup occurs, it sequentially triggers problems such as a surge in belly pressure, difficulty in maintaining blast volume, a slowdown in material feed rate, a decrease in tapping velocity, a continuous decline in taphole depth, and slag burn-out at the tuyeres. If not predicted and addressed in time, it can further induce suspended charge, collapse, hearth accumulation, and even blast furnace shutdown, significantly increasing the fuel ratio for ironmaking and severely hindering the long-term stable operation of the blast furnace. Therefore, accurate and proactive prediction of blast furnace slag buildup is crucial for ensuring safe and efficient blast furnace ironmaking production.

[0003] Currently, the industry's judgment on blast furnace blockage relies entirely on manual experience and monitoring of single operating parameters, resulting in significant lag and a high misjudgment rate. Specific shortcomings include: 1. Judgment based on single airflow parameters: Relying on furnace pressure differential and permeability index to judge blast furnace blockage can only identify the later stages of airflow blockage, lagging behind slag and iron accumulation by 3-4 hours, failing to provide early warning; furthermore, furnace temperature fluctuations, abnormal charging, and short-term material collapses can all cause pressure differential fluctuations, leading to inaccurate judgments. 2. Judgment based on experience with tapping parameters: Relying on manual judgment of tapping volume, taphole depth, and slag flow velocity is a reactive approach, only discovering the blockage after a large amount of slag and iron has accumulated, missing the optimal window for intervention. Summary of the Invention

[0004] The purpose of this invention is to provide a method and system for judging blast furnace bridging based on nitrogen-carbon dual-balance coupling, in order to address the shortcomings of existing technologies and solve the problem of inaccurate judgment results in existing technologies.

[0005] The technical solution adopted in this invention is: a method for judging blast furnace bridging based on nitrogen-carbon dual-balance coupling, the method comprising the following steps: Step 1: Calculate the amount of gas generated per ton of iron based on the carbon balance principle; Step 2: Calculate the total amount of gas generated in the blast furnace based on the nitrogen balance principle; Step 3: Based on the total amount of gas generated and the amount of gas generated per ton of iron, and using the corresponding relationship between the total amount of gas generated and the gas consumption per unit of molten iron, calculate the amount of pig iron produced per minute in the blast furnace hearth. Step 4: Calculate the amount of iron produced per minute in the blast furnace hearth and compare it with the amount of pig iron produced per minute obtained in Step 3. Make a preliminary judgment on the blast furnace iron blockage based on the comparison results. Step 5: Based on the preliminary judgment results of Step 4, and combined with the characteristics of abnormal operating conditions, make the final judgment on blast furnace slag buildup.

[0006] According to the above scheme, the final determination method for blast furnace bridging in step five is as follows: (1) If step four has preliminarily determined that there is no iron buildup in the blast furnace, then the final determination is that there is no iron buildup in the blast furnace, and there is no need to perform the abnormal operating condition characteristic verification in this step. (2) If step four has preliminarily determined that the blast furnace is experiencing blast furnace blockage, then further verify whether the blast furnace simultaneously exhibits two or more of the following abnormal operating conditions: If two or more of the above abnormal operating conditions are simultaneously present, then it is finally determined that the blast furnace is experiencing blast furnace blockage, and intervention measures should be taken in a timely manner; if fewer than two abnormal operating conditions are present, then it is finally determined that the blast furnace is not experiencing blast furnace blockage; among which, the abnormal operating conditions are: (a) Abnormal pressure under stable airflow conditions; (b) Abnormal fluctuations in furnace top pressure; (c) Abnormal air outlet operating conditions; (d) Abnormal furnace charge feeding.

[0007] According to the above scheme, in step four, the actual iron tapping parameters are defined, including: the total iron tapping amount Q per unit time. 单位时间出铁总量 The unit is t; the tapping time is t. 出铁时长 The unit is min; the iron output Q per minute. 出 ; Blast furnace pig iron production per minute (T) （生铁） The unit is t / min; Among them, Q 出 =Q 单位时间出铁总量 / t 出铁时长 ; The preliminary method for determining blast furnace bridging is as follows: (1) When Q 出 ≧T （生铁） At that time, the actual tapping rate is greater than or equal to the iron generation rate, the slag and iron in the hearth are discharged in time, the furnace condition is normal, and there is no risk of iron blockage. (2) When Q 出 <T （生铁） At that time, the rate of molten iron generation was greater than the actual discharge rate, and slag and iron in the hearth continued to accumulate, and the liquid level gradually rose, indicating that there was an abnormality of molten iron blockage in the blast furnace.

[0008] According to the above scheme, the calculation method for the amount of iron ore gas generated in step one is as follows: First, calculate the total input carbon content C. （进） Calculate the total output carbon content C （出）Based on the total input carbon content and total output carbon content, the effective carbon content of the gas entering the furnace is calculated. Then, the volume ratio of each component of the gas at the top of the furnace is collected. Combined with the effective carbon content of the gas entering the furnace and the carbon-based component ratio of the gas, the gas consumption per ton of iron is calculated, which is also the gas generation per ton of iron.

[0009] According to the above scheme, in step one, the total input carbon content C is calculated. （进） At that time, carbon elements were introduced from three types of raw materials: coke, pulverized coal, and ore. The total input carbon content was obtained by summing up the individual calculations.

[0010] According to the above scheme, in step one, the total output carbon content C is calculated. （出） At that time, carbon elements were removed through carburizing of molten iron and emission of gas ash. The total output carbon content C was obtained by summing up the individual calculations. （出） .

[0011] According to the above plan, in step one, the amount of gas generated per ton of iron ore is V. (吨铁煤气发生量) =C (进入煤气) ×22.4×100 / 12 / [Φ (co%) +Φ (CO2%) ].

[0012] In the formula, C (进入煤气) The effective carbon content entering the gas, expressed in kg / t; Φ (co%) Φ represents the volume percentage of CO in the blast furnace top gas; (CO2%) This represents the volume percentage of CO2 in the blast furnace top gas.

[0013] According to the above scheme, in step two, the total amount of gas generated in the blast furnace, V (煤气总量) The calculation method is as follows: First, calculate the oxygen content and nitrogen content in the air; then calculate the total amount of nitrogen brought in from the outside; finally, calculate the total amount of gas produced by the blast furnace based on the nitrogen balance.

[0014] According to the above scheme, the formula for calculating the pig iron production per minute in the blast furnace hearth in step three is as follows: T （生铁） =V (煤气总量) / V (吨铁煤气发生量)； In the formula: T （生铁） This represents the amount of pig iron produced by the blast furnace per minute, expressed in t / min.

[0015] This invention also employs a blast furnace bridging judgment system based on nitrogen-carbon dual-balance coupling, including a data acquisition module, a carbon balance calculation module, a nitrogen balance calculation module, a pig iron production calculation module, a preliminary bridging judgment module, a final bridging judgment module, and an output module; wherein: The data acquisition module is used to collect relevant parameters of the blast furnace; The carbon balance calculation module is connected to the data acquisition module and is used to calculate the amount of coal gas generated per ton of iron based on the carbon balance principle. The nitrogen balance calculation module is connected to the data acquisition module and is used to calculate the total amount of gas generated in the blast furnace according to the nitrogen balance principle. The pig iron production calculation module is connected to the carbon balance calculation module and the nitrogen balance calculation module respectively, and is used to calculate the pig iron production per minute in the blast furnace hearth. The preliminary iron stagnation determination module is connected to the data acquisition module and the pig iron production calculation module respectively, and is used to calculate the iron output per minute and output the preliminary iron stagnation determination result of the blast furnace. The final determination module for blast furnace bridging is connected to the preliminary determination module for blast furnace bridging and is used to output the final determination result for blast furnace bridging based on the preliminary determination result and the characteristics of abnormal blast furnace operating conditions. The output module is connected to the final determination module for blast furnace bridging and is used to output the final determination result of blast furnace bridging.

[0016] The beneficial effects of this invention are as follows: 1. Existing technologies require waiting for a large accumulation of slag and iron and for the permeable space of the hearth to be compressed before identifiable abnormal signals such as pressure difference and permeability index appear. In contrast, this invention starts directly from the balance of smelting materials, calculates the amount of gas generated per ton of iron based on carbon balance and the total amount of blast furnace gas generated based on nitrogen balance, and derives the real-time pig iron generation rate in the hearth by coupling these calculations. It does not rely on indirect derived parameters such as pressure difference, which are easily affected by furnace temperature fluctuations, abnormal material distribution, and short-term material collapse. This avoids false signals caused by external operating conditions, and the judgment results are more accurate, solving the problem of inaccurate judgment results of existing technologies for pig iron buildup. Furthermore, this invention can capture the signs of pig iron buildup at the beginning of the slag and iron accumulation stage through quantitative calculation of the iron generation rate and production conditions, without waiting for later phenomena such as airflow blockage to appear. This eliminates the inherent time lag of the original method, realizes the early identification of pig iron buildup faults, reserves sufficient handling window for blast furnace condition intervention, and reduces the risk of hanging material, material collapse, and unplanned blast shutdown.

[0017] 2. Based on the initial assessment by rate comparison, this invention introduces multiple abnormal blast furnace operating condition characteristics for secondary verification. Only when iron stagnation is initially determined and at least two abnormal operating condition characteristics are met simultaneously can the iron stagnation fault be confirmed. This can effectively eliminate parameter interference caused by furnace temperature fluctuations, charging disturbances, and short-term material collapse, avoid misjudgments caused by relying solely on rate calculations, further improve the reliability of the final iron stagnation determination result, and reduce false alarms and unnecessary furnace condition adjustment operations in production.

[0018] 3. This invention quantifies the amount of pig iron produced per minute in the blast furnace hearth and the actual amount of iron tapped per minute, using the relationship between the two values ​​as a preliminary criterion for molten iron buildup. This transforms the qualitative experience-based judgment that previously relied on manual observation of iron flow and taphole depth into a calculable quantitative indicator. It can reflect the matching relationship between molten iron generation and discharge in the hearth in real time, quickly identify the root cause of molten iron buildup when molten iron generation exceeds iron tapping, and provide objective and reproducible quantitative evidence for the final judgment.

[0019] 4. The method described in this invention is based on the principle of conservation of carbon and nitrogen elements, and is not affected by fluctuations in blast furnace volume, raw material ratio, coal ratio, or oxygen enrichment process. It is suitable for large, medium, and small ironmaking blast furnaces. It only relies on existing blast furnace detection instruments to collect process parameters, without the need for large-scale hardware modifications to the production system. The implementation method is simple, the promotion and application cost is low, and it has strong on-site practicality and universality. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] In the description of the embodiments of this application, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0024] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0025] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples, without contradiction. Additionally, the term "a plurality of" indicates two or more.

[0026] like Figure 1 The method shown is a blast furnace bridging judgment method based on nitrogen-carbon dual-balance coupling. The method includes the following steps: Step 1: Calculate the amount of gas generated per ton of iron based on the carbon balance principle; Step 2: Calculate the total amount of gas generated in the blast furnace based on the nitrogen balance principle; Step 3: Based on the total amount of gas generated and the amount of gas generated per ton of iron, and using the corresponding relationship between the total amount of gas generated and the gas consumption per unit of molten iron, calculate the amount of pig iron produced per minute in the blast furnace hearth. Step 4: Calculate the amount of iron produced per minute in the blast furnace hearth and compare it with the amount of pig iron produced per minute obtained in Step 3. Make a preliminary judgment on the blast furnace iron blockage based on the comparison results. Step 5: Based on the preliminary judgment results of Step 4, and combined with the characteristics of abnormal operating conditions, make the final judgment on blast furnace slag buildup.

[0027] In step one of this invention, based on the principle of carbon conservation in blast furnace smelting, the input and output of carbon elements during the smelting of ton of iron are statistically analyzed, the effective carbon content entering the blast furnace gas is calculated, and the gas production per ton of iron is calculated in combination with the composition parameters of the top gas.

[0028] The process parameters, units, and corresponding values ​​required for this calculation are defined as follows: coke ratio (kg / t, a); coke carbon content (%, b); coal ratio (kg / t, c); pulverized coal carbon content (%, d); ore consumption (kg / t, e); ore carbon content (%, f); hot metal carburization (kg / t, g); gas and ash content (kg / t, h); and gas carbon content (%, i). These parameters are detailed in Table 1. The parameters in Table 1 can be obtained from the blast furnace batching and weighing system and the test data of raw materials, hot metal, and dust collector ash. For example, the coke ratio / coal ratio / ore consumption are given by the weighing system; the coke carbon content, pulverized coal carbon content, ore carbon content, hot metal carburization, and gas and ash carbon content are given by the laboratory industrial analysis; and the gas and ash content is given by the dust collector ash metering.

[0029] Table 1. Process parameters, units, and corresponding values

[0030] In step one of this invention, the calculation process for the amount of gas generated per ton of iron is as follows: 1. Calculate the total input carbon content C （进） Carbon is mainly introduced from three types of raw materials: coke, pulverized coal, and ore. The total input carbon content, or C, is obtained by summing up the individual components after calculation. （进） =C (焦炭) +C (煤粉) +C (矿石) .in: The carbon content C brought in by coke (焦炭) =a×b; The carbon content C introduced by pulverized coal (煤粉) =c×d; Carbon content C brought in by the ore (矿石) =e×f.

[0031] 2. Calculate the total output carbon content C （出） Carbon is mainly removed through carburizing of molten iron and the emission of gas ash. The total output carbon content C is obtained by summing up the individual components. （出） =C （铁水渗碳） +C （瓦斯灰）。

[0032] Among them: Carbon content carried out by carburization of molten iron: C （铁水渗碳） =g; Carbon content carried out by gas ash: C （瓦斯灰） =h×i.

[0033] Total output carbon content: C （出） =C （铁水渗碳） +C （瓦斯灰） 3. Based on the obtained total input carbon content and total output carbon content, calculate the effective carbon content entering the gas: According to the carbon balance principle, after subtracting the carbon content fixed in the molten iron and lost with gas ash from the total input carbon content, the remaining carbon content participates in combustion and gasification and enters the blast furnace gas, thus obtaining the effective carbon content C entering the gas. (进入煤气) C (进入煤气) =C （进） -C （出） .

[0034] 4. Collect the volume percentage of each component of the top gas, and combine it with the effective carbon content of the gas and the percentage of carbon-based components in the gas to calculate the gas consumption per ton of iron, that is, the gas generation per ton of iron.

[0035] In this invention, the volume percentage parameters of each component in the blast furnace top gas are defined as follows: CO volume percentage Φ (co%) CO2 volume percentage Φ (CO2%) N2 volume percentage Φ (N2%) As shown in Table 2, the parameters in Table 2 can be obtained in real time by an online component analyzer for blast furnace top gas.

[0036] Table 2. Composition of blast furnace top gas and corresponding values

[0037] Therefore, the amount of gas generated per ton of iron ore is V (吨铁煤气发生量) =C (进入煤气) ×22.4×100 / 12 / [Φ (co%) +Φ (CO2%) ].

[0038] In step one, C (进入煤气) All carbon content values ​​are expressed in kg / t.

[0039] In step two of this invention, based on the principle of nitrogen conservation, nitrogen does not participate in chemical reactions during blast furnace smelting; it only migrates with the flow of coal gas. By statistically analyzing the total amount of nitrogen entering the furnace and combining it with the nitrogen ratio of the coal gas at the furnace top, the total amount of coal gas generated in the blast furnace is calculated.

[0040] The relevant process parameters, units, and corresponding values ​​for blast furnace air supply and nitrogen replenishment required in this step are defined as follows: Blast furnace air volume, unit is m³ / min, and the value is Q. (风量) Oxygen content, in units of m³ / h, is represented by the value Q. (氧量) The amount of nitrogen introduced by the injection carrier, in m³ / h, is represented by the value Q. (喷吹载气带入N2) The amount of nitrogen introduced into the furnace top gearbox seal, in m³ / h, is represented by the value Q. (炉顶齿轮箱带入N2) The amount of nitrogen introduced through the static pressure orifice, in m³ / h, is represented by the value Q. (静压力孔带入N2)As shown in Table 3, the parameter values ​​in Table 3 can also be obtained through existing conventional technologies. For example, the air volume and oxygen volume parameters are taken from the flow meter of the blower system, and the N2 brought in by the injection carrier gas / furnace top gearbox / static pressure hole comes from the flow meter of each nitrogen branch.

[0041] Table 3. Relevant process parameters, units, and corresponding values ​​for blast furnace blast and nitrogen supply.

[0042] In this step, the total amount of gas generated in the blast furnace, V (煤气总量) The calculation process is as follows: 1. Calculate the oxygen and nitrogen content in the wind.

[0043] Oxygen content in wind W (风中含氧率) =[21%×(Q (风量) -Q (氧量) / 60)+Q (氧量) / 60] / Q (风量)； Nitrogen content in wind W (风中含氮率) =100-W (风中含氧率) .

[0044] 2. Calculate the total amount of nitrogen introduced from external sources: Calculate the total amount of nitrogen introduced through all external channels, including blast furnace injection carrier gas, furnace top gearbox, and static pressure orifice. The total amount of nitrogen introduced from external sources is Q. (外部带入氮气) for: Q (外部带入氮气) =Q (喷吹载气带入N2) +Q (炉顶齿轮箱带入N2) +Q (静压力孔带入N2) .

[0045] 3. Calculate the total amount of gas produced by the blast furnace, V, based on the nitrogen balance. (煤气总量) : According to the nitrogen balance, the ratio of the total effective nitrogen entering the furnace to the nitrogen content of the top gas is the total real-time blast furnace gas generation V. (煤气总量) The calculation formula is as follows: V (煤气总量) =(Q (风量) ×W (风中含氮率) -Q (外部带入氮气) ) / Φ (N2%) .

[0046] In step three of this invention, the amount of gas generated per ton of iron ore, V, is based on the amount obtained in step one. (吨铁煤气发生量) The total amount of gas produced, V, obtained in step two (煤气总量) By analyzing the relationship between gas production and gas consumption per unit of molten iron, the pig iron production per minute in the blast furnace hearth is calculated using the following formula: T （生铁） =V (煤气总量) / V(吨铁煤气发生量) ; In the formula: T （生铁） This represents the amount of pig iron produced by the blast furnace per minute, expressed in t / min. This parameter accurately reflects the real-time output efficiency of molten iron from the hearth.

[0047] In this invention, the cause of blast furnace slag buildup is that the rate of molten iron generation in the hearth exceeds the actual iron tapping rate, leading to continuous accumulation of slag and iron and a rise in the liquid level. By calculating the blast furnace's iron tapping rate per minute and comparing it with the blast furnace's pig iron production rate per minute, a preliminary prediction of slag buildup is made based on the calculation results.

[0048] In step four of this section, the actual iron tapping parameters are defined, including: the total iron tapping volume Q per unit time. 单位时间出铁总量 (Can be measured in real time by the molten iron weighing system), unit is t; tapping time t 出铁时长 The unit is min; the iron output Q per minute. 出 ; Among them, Q 出 =Q 单位时间出铁总量 / t 出铁时长 .

[0049] In step four of this process, the preliminary method for determining blast furnace bridging is as follows: 1. When Q 出 ≧T （生铁） At that time, the actual tapping rate is greater than or equal to the iron generation rate, the slag and iron in the hearth can be discharged in time, the furnace condition is normal, and there is no risk of iron blockage. 2. When Q 出 <T （生铁） At that time, the rate of molten iron generation was greater than the actual discharge rate, and slag and iron in the hearth continued to accumulate, and the liquid level gradually rose, indicating that there was an abnormality of molten iron blockage in the blast furnace.

[0050] To avoid the judgment error of a single rate comparison and improve the accuracy of blast furnace blockage judgment, step five combines the preliminary judgment results of step four with the actual operating conditions such as blast furnace air pressure, furnace top pressure, tuyeres status, and charging speed for coupled verification, and finally confirms the blast furnace blockage condition.

[0051] The final determination method for blast furnace bridging in step five of this process is as follows: (1) If step four has preliminarily determined that there is no iron buildup in the blast furnace, then the final determination is that there is no iron buildup in the blast furnace, and there is no need to perform the abnormal operating condition characteristic verification in this step. (2) If step four has preliminarily determined that the blast furnace is stuck, then further verify whether the blast furnace has two or more of the following abnormal operating conditions at the same time: If two or more of the above abnormal operating conditions are present at the same time, then it is finally determined that the blast furnace has a stuck iron fault and intervention measures should be taken in time; if there are less than two abnormal operating conditions, then it is finally determined that the blast furnace is not stuck iron. The characteristics of abnormal operating conditions are as follows: (a) Abnormal pressure under stable air volume conditions, specifically manifested as follows: when the blast furnace air volume fluctuation is controlled within ±500m³ / min, the air pressure rises by 0.01~0.05MPa, and the furnace belly pressure difference rises by 0.01~0.05MPa simultaneously. (b) Abnormal fluctuation of furnace top pressure, specifically manifested as: within two adjacent iron tapping intervals, the furnace top pressure fluctuation exceeds ±0.03MPa, and the pressure stability decreases significantly; (c) Abnormal tuyere conditions, specifically manifested as: the blast furnace temperature is within the normal and controllable range, but the tuyere appears dark and there is no normal bright flame, which is a typical characteristic of slag and iron accumulation in the hearth and poor air and liquid permeability. (d) Abnormal furnace charge feeding, specifically manifested as: the blast furnace charging rate slowed down significantly, reduced by 1 to 2 batches compared to the normal production charging speed, and material transmission was obstructed; A blast furnace bridging detection system based on nitrogen-carbon dual-balance coupling includes a data acquisition module, a carbon balance calculation module, a nitrogen balance calculation module, a pig iron production calculation module, a preliminary bridging detection module, a final bridging detection module, and an output module; wherein: The data acquisition module is used to collect relevant parameters of the blast furnace, specifically including raw material parameters, operating parameters, and top gas composition parameters. The raw material parameters include coke ratio, coke carbon content, coal ratio, pulverized coal carbon content, ore consumption, ore carbon content, molten iron carburization, gas sludge content, and gas ash carbon content. The operating parameters include air volume, oxygen content, nitrogen volume introduced by the injection carrier, nitrogen volume introduced by the top gearbox, nitrogen volume introduced by the static pressure orifice, total iron output per unit time, and iron output duration. The top gas composition parameters include the volume percentages of CO, CO2, H2, and N2. The carbon balance calculation module is connected to the data acquisition module and is used to calculate the effective carbon content entering the gas based on the raw material parameters according to the carbon balance principle, and to calculate the amount of gas generated per ton of iron by combining the volume ratio of CO and CO2 in the top gas of the furnace. The nitrogen balance calculation module is connected to the data acquisition module and is used to calculate the nitrogen content in the air and the total amount of nitrogen brought in from the outside based on the operating parameters according to the nitrogen balance principle, and to calculate the total amount of gas generated in the blast furnace in combination with the volume ratio of N2 in the top gas. The pig iron production calculation module is connected to the carbon balance calculation module and the nitrogen balance calculation module respectively, and is used to calculate the pig iron production per minute in the blast furnace hearth based on the ratio of the total gas production to the gas production per ton of iron. The preliminary iron stagnation determination module is connected to the data acquisition module and the pig iron production calculation module, respectively. It is used to calculate the actual iron output per minute based on the total iron output per unit time and the iron output duration, compare the actual iron output per minute with the pig iron production per minute, and output the preliminary iron stagnation determination result based on the comparison result. The final determination module for blast furnace bridging is connected to the preliminary determination module for blast furnace bridging. It is used to output the final determination result for blast furnace bridging based on the preliminary determination result and the abnormal operating conditions of the blast furnace. The abnormal operating conditions include abnormal pressure under stable air volume, abnormal pressure fluctuation at the furnace top, abnormal tuyeres, and abnormal charging of furnace charge. The output module is connected to the blast furnace bridging final determination module and is used to output the final determination result of the blast furnace bridging and trigger an early warning when the blast furnace is finally determined to have a bridging fault.

[0052] Example A blast furnace operating under actual conditions was selected as the verification object. Relevant parameters under this condition were collected, including coke ratio, coke carbon content, coal ratio, pulverized coal carbon content, ore consumption, ore carbon content, molten iron carburization, gas sludge content and gas ash carbon content, air volume, oxygen content, nitrogen introduced by the injection carrier, nitrogen introduced by the furnace top gearbox, nitrogen introduced by the static pressure orifice, actual total iron output and iron output time, and the volume percentage of CO, CO2 and N2 in the furnace top gas. The values ​​of each parameter are shown in Tables 4 and 5.

[0053] Table 4. Relevant process parameters and values ​​for blast furnace blast and nitrogen supply.

[0054] Table 5. Parameter values ​​in the embodiments

[0055] The calculations are performed sequentially according to steps one through five of this invention: First, the amount of gas generated per ton of iron ore, V, is calculated based on the carbon balance. (吨铁煤气发生量) : C (焦炭) =a×b=380×0.86=326.8kg / t; C (煤粉) =c×d=150×0.75=112.5 kg / t; C (矿石) =e×f=1700×0.003=5.1 kg / t; C (进) =444.4 kg / t.

[0056] C (铁水渗碳) =g=45 kg / t; C (瓦斯灰) =h×i=20×0.30=6.0 kg / t; C(出) =51.0 kg / t.

[0057] C (进入煤气) =C (进) C (出) =444.4 51.0 = 393.4 kg / t.

[0058] V (吨铁煤气发生量) =C (进入煤气) ×22.4×100 / 12 / [Φ (co%) +Φ (CO2%) ] =393.4×22.4×100 / 12 / (23+22)≈1632 m³ / t.

[0059] Secondly, the total amount of gas generated in the blast furnace, V, is calculated based on nitrogen balance. (煤气总量) : W (风中含氧率) =[21%×(5000 [8000 / 60) + 8000 / 60] / 5000 ≈ 0.231, which is 23.1%; W (风中含氮率) =1 0.231 = 0.769.

[0060] Q (外部带入氮气) =(50+30+20) / 60≈1.67 m³ / min.

[0061] V (煤气总量) =(Q (风量) ×W (风中含氮率) Q (外部带入氮气) ) / Φ (N2%) =(5000×0.769 1.67) / 0.52≈7391m³ / min.

[0062] Then, calculate the pig iron production per minute (T) based on the ratio of the total gas production to the gas production per ton of iron. （生铁） ; T (生铁) =V (煤气总量) / V (吨铁煤气发生量) =7391 / 1632≈4.53 t / min; Calculate the actual iron output Q per minute 出 This was compared with the amount of pig iron produced per minute to make a preliminary judgment on iron accumulation. The preliminary judgment result was as follows: Q was calculated... 出 =Q 单位时间出铁总量 / t 出铁时长=200 / 45≈4.44 t / min; due to Q 出 <T (生铁) The rate of molten iron generation was greater than the actual discharge rate, and it was initially determined that there was an abnormality of molten iron buildup in the blast furnace.

[0063] Finally, a final judgment was made based on the abnormal operating conditions, including blast furnace air pressure, pressure difference, furnace top pressure fluctuations, tuyere status, and charging speed. This operating condition exhibited the following abnormal characteristics simultaneously: (a) Abnormal pressure under stable air volume conditions: within ±500 m³ / min of air volume fluctuation, the air pressure rises by 0.03 MPa; (b) Abnormal fluctuation of furnace top pressure: The furnace top pressure fluctuation in adjacent tapping intervals is > ±0.03 MPa; (c) Abnormal tuyere conditions: The furnace temperature is normal, but the tuyere is dark and there is no bright flame; (d) Abnormal charge feeding: The charging rate slowed down by about 2 batches.

[0064] There are a total of 4 abnormal operating conditions (≥2), and the final judgment is: the blast furnace has experienced a blast furnace blockage, and timely intervention and disposal measures are required; this judgment result is consistent with the actual furnace condition.

[0065] Comparative Example This comparative example uses the existing differential pressure threshold alarm standard in the industry to synchronously monitor the same working condition in Example 1: In the early stage of slag and iron accumulation, the differential pressure in the furnace belly only increased slightly (about 0.5 kPa), which did not reach the alarm threshold set by the existing technology, so the conclusion was that there was no iron buildup (missed alarm); it was not identified until a large amount of slag and iron accumulated and the differential pressure soared, which was about 3 to 4 hours late, and during this period, secondary anomalies such as dark red tuyeres and slowed material feeding had already occurred.

[0066] Comparing the judgment results of the examples and comparative examples, the results show that the method of the present invention, through the coupled calculation of nitrogen balance and carbon balance, can achieve early warning in the early stage of slag and iron accumulation, and the judgment time is 3 to 4 hours earlier than the existing technology. At the same time, by combining the quantitative comparison of pig iron production and actual iron output with the comprehensive verification of multi-dimensional abnormal operating conditions, the pressure difference interference caused by factors such as furnace temperature fluctuation, abnormal charging and short-term collapse is effectively eliminated. The judgment accuracy is higher than that of existing conventional technical means, and the false alarm rate is greatly reduced, which can provide a reliable basis for the timely handling of blast furnace iron stagnation faults.

[0067] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0068] Finally, it should be noted that the above are merely preferred embodiments of this application and are not intended to limit this application. Although this application has been described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. However, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for judging blast furnace bridging based on nitrogen-carbon dual-balance coupling, characterized in that, The method includes the following steps: Step 1: Calculate the amount of gas generated per ton of iron based on the carbon balance principle; Step 2: Calculate the total amount of gas generated in the blast furnace based on the nitrogen balance principle; Step 3: Based on the total amount of gas generated and the amount of gas generated per ton of iron, and using the corresponding relationship between the total amount of gas generated and the gas consumption per unit of molten iron, calculate the amount of pig iron produced per minute in the blast furnace hearth. Step 4: Calculate the amount of iron produced per minute in the blast furnace hearth and compare it with the amount of pig iron produced per minute obtained in Step 3. Make a preliminary judgment on the blast furnace iron blockage based on the comparison results. Step 5: Based on the preliminary judgment results of Step 4, and combined with the characteristics of abnormal operating conditions, make the final judgment on blast furnace slag buildup.

2. The blast furnace bridging judgment method based on nitrogen-carbon dual-balance coupling as described in claim 1, characterized in that, The final determination method for blast furnace bridging in step five is as follows: (1) If step four has preliminarily determined that there is no iron buildup in the blast furnace, then the final determination is that there is no iron buildup in the blast furnace, and there is no need to perform the abnormal operating condition characteristic verification in this step. (2) If step four has preliminarily determined that the blast furnace is experiencing blast furnace blockage, then further verify whether the blast furnace simultaneously exhibits two or more of the following abnormal operating conditions: If two or more of the above abnormal operating conditions are simultaneously present, then it is finally determined that the blast furnace is experiencing blast furnace blockage, and intervention measures should be taken in a timely manner; if fewer than two abnormal operating conditions are present, then it is finally determined that the blast furnace is not experiencing blast furnace blockage; among which, the abnormal operating conditions are: (a) Abnormal pressure under stable airflow conditions; (b) Abnormal fluctuations in furnace top pressure; (c) Abnormal air outlet operating conditions; (d) Abnormal furnace charge feeding.

3. The blast furnace bridging judgment method based on nitrogen-carbon dual-balance coupling as described in claim 1, characterized in that, In step four, the actual iron tapping parameters are defined, including: the total iron tapping amount Q per unit time. 单位时间出铁总量 The unit is t; the tapping time is t. 出铁时长 The unit is min; the iron output Q per minute. 出 ; Blast furnace pig iron production per minute (T) （生铁） The unit is t / min; Among them, Q 出 =Q 单位时间出铁总量 / t 出铁时长 ; The preliminary method for determining blast furnace bridging is as follows: (1) When Q 出 ≧T （生铁） At that time, the actual tapping rate is greater than or equal to the iron generation rate, the slag and iron in the hearth are discharged in time, the furnace condition is normal, and there is no risk of iron blockage. (2) When Q 出 <T （生铁） At that time, the rate of molten iron generation was greater than the actual discharge rate, and slag and iron in the hearth continued to accumulate, and the liquid level gradually rose, indicating that there was an abnormality of molten iron blockage in the blast furnace.

4. The blast furnace bridging judgment method based on nitrogen-carbon dual-balance coupling as described in claim 1, characterized in that, In step one, the calculation method for the amount of gas generated per ton of iron ore is as follows: First, calculate the total input carbon content C. （进） Calculate the total output carbon content C （出） Based on the total input carbon content and total output carbon content, the effective carbon content of the gas entering the furnace is calculated. Then, the volume ratio of each component of the gas at the top of the furnace is collected. Combined with the effective carbon content of the gas entering the furnace and the carbon-based component ratio of the gas, the gas consumption per ton of iron is calculated, which is also the gas generation per ton of iron.

5. The blast furnace bridging judgment method based on nitrogen-carbon dual-balance coupling as described in claim 4, characterized in that, In step one, the total input carbon content C is calculated. （进） At that time, carbon elements were introduced from three types of raw materials: coke, pulverized coal, and ore. The total input carbon content was obtained by summing up the individual calculations.

6. The blast furnace bridging judgment method based on nitrogen-carbon dual-balance coupling as described in claim 4, characterized in that, In step one, the total output carbon content C is calculated. （出） At that time, carbon elements were removed through carburizing of molten iron and emission of gas ash. The total output carbon content C was obtained by summing up the individual calculations. （出） .

7. The blast furnace bridging judgment method based on nitrogen-carbon dual-balance coupling as described in claim 4, characterized in that, In step one, the amount of gas generated per ton of iron ore is V. (吨铁煤气发生量) =C (进入煤气) ×22.4×100 / 12 / [Φ (co%) +Φ (CO2%) ]; In the formula, C (进入煤气) The effective carbon content entering the gas, expressed in kg / t; Φ (co%) Φ represents the volume percentage of CO in the blast furnace top gas; (CO2%) This represents the volume percentage of CO2 in the blast furnace top gas.

8. The blast furnace bridging judgment method based on nitrogen-carbon dual-balance coupling as described in claim 7, characterized in that, In step two, the total amount of gas generated in the blast furnace, V (煤气总量) The calculation method is as follows: First, calculate the oxygen content and nitrogen content in the air; then calculate the total amount of nitrogen brought in from the outside; finally, calculate the total amount of gas produced by the blast furnace based on the nitrogen balance.

9. The blast furnace bridging judgment method based on nitrogen-carbon dual-balance coupling as described in claim 8, characterized in that, In step three, the formula for calculating the amount of pig iron produced per minute in the blast furnace hearth is as follows: T （生铁） =V (煤气总量) / V (吨铁煤气发生量)； In the formula: T （生铁） This represents the amount of pig iron produced by the blast furnace per minute, expressed in t / min.

10. A blast furnace bridging judgment system based on nitrogen-carbon dual-balance coupling, characterized in that, It includes a data acquisition module, a carbon balance calculation module, a nitrogen balance calculation module, a pig iron production calculation module, a preliminary pig iron accumulation assessment module, a final pig iron accumulation assessment module, and an output module; among which: The data acquisition module is used to collect relevant parameters of the blast furnace; The carbon balance calculation module is connected to the data acquisition module and is used to calculate the amount of coal gas generated per ton of iron based on the carbon balance principle. The nitrogen balance calculation module is connected to the data acquisition module and is used to calculate the total amount of gas generated in the blast furnace according to the nitrogen balance principle. The pig iron production calculation module is connected to the carbon balance calculation module and the nitrogen balance calculation module respectively, and is used to calculate the pig iron production per minute in the blast furnace hearth. The preliminary iron stagnation determination module is connected to the data acquisition module and the pig iron production calculation module respectively, and is used to calculate the iron output per minute and output the preliminary iron stagnation determination result of the blast furnace. The final determination module for blast furnace bridging is connected to the preliminary determination module for blast furnace bridging and is used to output the final determination result for blast furnace bridging based on the preliminary determination result and the characteristics of abnormal blast furnace operating conditions. The output module is connected to the final determination module for blast furnace bridging and is used to output the final determination result of blast furnace bridging.

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