A sintering pallet step air supply reinforced sintering method

Abstract

This invention belongs to the field of sintering technology, specifically relating to a tiered air supply method for enhancing sintering on a sintering trolley. The technical solution is as follows: In multiple air boxes arranged along the trolley's running direction on the sintering machine, based on the differences in combustion state, melting state, and permeability of the sintering material layer corresponding to each air box position during the sintering process, and under the condition that the overall ventilation capacity of the sintering machine is basically stable, an air volume weighting factor is introduced to non-uniformly and tieredly distribute the air volume of each air box, using the total average sintering air volume as a benchmark. This air volume weighting factor is related to dimensionless melting state parameters, dimensionless vertical sintering speed parameters, and dimensionless material layer permeability parameters, achieving dynamic matching between the air supply volume of each air box and the material layer state. This ensures that the sintering material layer corresponding to different air box positions receives an air volume supply matching its state, thereby improving the temperature distribution and melting state of the sintering material layer. This invention can improve the thermal distribution during the sintering process, increase the quality of sintered ore, and also improve sintering efficiency.

Description

Technical Field

[0001] This invention belongs to the field of sintering process technology, specifically relating to a step-by-step air supply method for enhancing sintering on a sintering trolley. Background Technology

[0002] In the iron ore sintering process, the sintering machine typically uses a main exhaust fan to draw air from multiple air boxes arranged along the running direction beneath the sintering trolley. This allows air to flow downwards through the sintering bed, providing the necessary oxygen for fuel combustion and the sintering reaction. A combustion zone is formed within the bed, propelling it downwards along the bed's thickness, ultimately completing the sintering process. The airflow distribution directly affects the bed temperature field, the morphology of the combustion zone, and the structure and properties of the sinter, making it a key factor in sintering process control.

[0003] In existing sintering production, airflow control mainly relies on adjusting the operating parameters of the main exhaust fan and the opening degree of each air box valve. Under a certain total exhaust capacity, the sintering process can be regulated by changing the opening degree of the air box valves or the frequency of the main exhaust fan. A common control approach is to adjust the airflow based on feedback information such as airflow, negative pressure, or flue gas parameters to maintain stable operation of the sintering process. For example, Chinese patent CN102997671A proposes a method for controlling the air volume of the sintering trolley's air boxes. This method uses the air volume of a designated air box as a benchmark and adjusts the valve openings of other air boxes based on the correspondence between air volume and valve opening, so that the air volume of each air box tends to be consistent, thereby achieving a balanced distribution of air volume. In addition, other technologies calculate the target air volume required for the sintering process based on information such as material layer thickness and flue gas composition, and achieve overall air volume control by adjusting the frequency of the main exhaust fan; or dynamically adjust the air box valve openings according to parameters such as the position, width, and migration speed of the combustion zone to improve the stability of the sintering process; or optimize and adjust the air volume of each air box in combination with the negative pressure distribution or wind resistance changes of the air boxes, so that the sintering process tends to be balanced in the direction of trolley operation, thereby reducing ineffective air volume and improving energy utilization efficiency.

[0004] Overall, existing sintering airflow control technologies are mainly based on single or a few process parameters, controlling airflow through balanced distribution or overall adjustment. While these methods have played a role in ensuring stable operation and reducing energy consumption during sintering, they often employ uniform air supply or overall adjustment, failing to reflect the non-uniformity of the sintering process along the trolley's direction of travel. Different air box positions correspond to material layers with significant differences in temperature, melting degree, and structural state, making it difficult to match airflow distribution with the material layer state, easily leading to localized under-sintering or over-melting. In terms of control methods, they often rely on feedback adjustment or empirical control, lacking a quantitative correlation between airflow and material layer state, making precise matching difficult. Regarding adjustment criteria, they are often based on single parameters, such as airflow, negative pressure, combustion zone characteristics, or wind resistance changes, failing to comprehensively consider factors such as the material layer's melting state, sintering propulsion speed, and material layer permeability. This makes it difficult to fully characterize the multi-factor coupling characteristics of the sintering process, resulting in limited accuracy in airflow distribution.

[0005] Existing technologies are unable to properly match the sintering material layer state differences at different wind box positions along the trolley's running direction, which can easily lead to local under-burning or over-melting. This not only affects the quality of sintered ore, but also results in low air volume utilization efficiency and high energy consumption. Summary of the Invention

[0006] This invention provides a cascade air supply method for enhancing sintering on a sintering trolley. By establishing a quantitative correlation between the sintering air volume of each air box and the melting state of the sintering material layer, the vertical sintering speed, and the permeability of the material layer, the non-uniform distribution of the sintering air volume of each air box along the sintering direction is achieved, thereby improving the thermal distribution during the sintering process, improving the quality of sintered ore, and taking into account sintering efficiency.

[0007] The technical solution of the present invention is as follows:

[0008] A tiered air supply method for enhancing sintering using a sintering trolley involves multiple air boxes arranged along the trolley's running direction in the sintering machine. Based on the differences in combustion state, melting state, and permeability of the sintering material layer corresponding to each air box position during the sintering process, and under the condition that the overall exhaust capacity of the sintering machine is basically stable, an air volume weighting factor is introduced to non-uniformly and tieredly distribute the air volume of each air box, using the total average sintering air volume as a benchmark. This air volume weighting factor is correlated with dimensionless melting state parameters, dimensionless vertical sintering speed parameters, and dimensionless material layer permeability parameters. This achieves dynamic matching between the air supply volume of each air box and the material layer state, ensuring that the sintering material layer corresponding to different air box positions receives an air volume supply matching its state, thereby improving the temperature distribution and melting state of the sintering material layer.

[0009] Furthermore, the cascade air supply method for enhancing sintering on the sintering trolley specifically includes the following steps:

[0010] Step 1: Based on the operating conditions of the sintering machine, obtain data on the material layer temperature distribution, combustion front position, and material layer pressure difference corresponding to each air box location;

[0011] Step 2: Calculate the dimensionless molten state parameter M corresponding to each windbox position based on the above data. i Dimensionless vertical sintering rate parameter V i and the dimensionless material layer permeability parameter K i ;

[0012] Step 3: Calculate the air volume weighting factor W for each air box based on the above parameters. i And normalize it to meet the total air volume conservation constraint;

[0013] Step 4: Determine the target air volume Q for each air box based on the air volume weighting factor. i ;

[0014] Step 5: By adjusting the opening of each air box valve, the actual air volume of each air box gradually approaches the corresponding target air volume, and correction adjustment is made when the deviation exceeds the set range, so as to achieve the step distribution of air volume;

[0015] Step Six: During the sintering process, the parameters are dynamically updated according to the changes in the state of the material layer, and the air volume distribution is adjusted in real time accordingly.

[0016] Furthermore, in the step one of the cascade air supply method for enhancing sintering on the sintering trolley, N air boxes are sequentially set along the trolley's running direction on the sintering machine, and each air box is sequentially numbered i=1, 2...N along the trolley's running direction.

[0017] Furthermore, in the cascade air supply method for enhancing sintering using the sintering trolley, in step two, the dimensionless molten state parameter M... i The molten state index (MQI) is obtained by dimensionless transformation of the sintering state index corresponding to the i-th wind box position. i The thermal intensity used to characterize the material layer at this location reaching a melting threshold temperature along its thickness is defined as follows:

[0018]

[0019] in, Let z represent the temperature distribution along the thickness direction of the sintered material layer corresponding to the i-th wind box position, z be the coordinate of the material layer thickness direction, H be the material layer thickness, and Tm be the effective melting threshold temperature; the dimensionless melting state parameter is defined as:

[0020]

[0021] Dimensionless vertical sintering rate parameter V iIt is determined by the ratio of the vertical sintering rate at the corresponding wind box position to the overall average vertical sintering rate; where the vertical sintering rate v at the i-th wind box position is... i It is determined by the rate of change of the position of the combustion front along the layer thickness direction, that is:

[0022]

[0023] in, This indicates the position of the combustion front in the sintering layer at the i-th wind box location along the thickness direction of the layer; the corresponding dimensionless vertical sintering velocity parameter is:

[0024]

[0025] Dimensionless material layer air permeability parameter K i The permeability characteristic index of the material layer is used for characterization; the permeability characteristic index k of the material layer at the i-th wind box position is... i Determined according to the following formula:

[0026]

[0027] Where A is the effective exhaust area, h is the bed height, and ΔP i The pressure difference between the bed and the corresponding wind box location; the dimensionless material bed permeability parameter is defined as:

[0028] .

[0029] Furthermore, in the cascade air supply method for enhancing sintering using the sintering trolley, in step three, the air volume weighting factor W... i This can be expressed as a weighted function of the dimensionless parameters mentioned above:

[0030]

[0031] in, , , Let be the weight coefficient, and satisfy... .

[0032] Furthermore, in the cascade air supply method for enhancing sintering on the sintering trolley, α = 0.4-0.6, b = 0.2-0.4, and c = 0.1-0.3.

[0033] Furthermore, in the cascade air supply method for enhancing sintering using the sintering trolley, in step four, the total average sintering air volume of the sintering machine under given operating conditions is Q. avg Then the sintering air volume Q of the i-th wind box i Air volume weighting factor W i It is determined that the relationship is as follows:

[0034] Qi =Q avg *W i .

[0035] Furthermore, in the cascade air supply method for enhancing sintering on the sintering trolley, in step five, under the premise of ensuring the overall ventilation capacity of the sintering machine remains stable, the sintering air volume of each air box is redistributed so that the change in the sintering air volume of each air box reflects an adjustment of the relative distribution relationship, rather than simply increasing or decreasing the total air volume. The air volume weighting factor of each air box should satisfy the following overall balance constraint conditions:

[0036] .

[0037] The beneficial effects of this invention are as follows:

[0038] 1. This invention establishes a quantitative correlation between sintering air volume and material bed state, and realizes non-uniform stepwise distribution of air volume based on multi-parameter coupling, specifically in the following aspects:

[0039] 1. The state of the sintering bed is introduced into the air volume distribution process. Dimensionless melting state parameters, dimensionless vertical sintering speed parameters, and dimensionless bed permeability parameters are used to characterize the bed state, so that the air volume distribution can reflect the bed's variation characteristics along the process.

[0040] Second, by constructing a functional relationship between the air volume weighting factor and the above-mentioned multiple state parameters, the air volume allocation is transformed from single-parameter control to multi-parameter coupled control, thereby improving the rationality and accuracy of air volume allocation.

[0041] Third, under the condition that the total ventilation capacity is basically stable, it is proposed to redistribute the air volume of each air box by using the air volume weighting factor, so that the air volume regulation is changed from overall regulation to distributed regulation, thereby improving the air volume utilization efficiency.

[0042] Fourth, a non-uniform stepped distribution method is adopted, so that the air volume along the sintering direction presents a variation pattern that matches the state of the material layer, which is different from the traditional uniform air supply or simple adjustment method.

[0043] Fifth, a dynamic update mechanism is introduced during implementation to adjust the air volume distribution in real time according to the sintering process operation status, so as to achieve dynamic matching between air volume and material layer status.

[0044] 2. This invention establishes a quantitative correlation between airflow and the state of the sintering bed, achieving a non-uniform, stepped distribution of airflow along the sintering direction. This matches the airflow of each windbox with the state of the sintering bed along the process, effectively avoiding local under-burning or over-melting, improving the microstructure of the sinter, and enhancing the uniformity and stability of the sinter quality. By introducing multi-parameter coupling relationships such as the molten state of the bed, vertical sintering speed, and bed permeability, the airflow distribution is transformed from single-parameter control to multi-parameter comprehensive regulation, making the airflow distribution more rational and improving the control accuracy of the sintering process. Under the condition that the total exhaust capacity is basically stable, by redistributing the airflow of each windbox, the proportion of effective airflow is increased, and the ineffective exhaust volume is reduced, thereby reducing the energy consumption of the sintering process and improving energy utilization efficiency. At the same time, optimizing the airflow distribution along the sintering process is beneficial to improving the temperature field and combustion zone morphology of the bed, making the sintering process more stable, and enhancing the controllability of the process operation and its adaptability to fluctuations in operating conditions.

[0045] 3. Without increasing the total air volume, this invention achieves synergistic optimization of sinter quality improvement, energy consumption reduction and process stability, and has good engineering application value. Detailed Implementation

[0046] A tiered air supply method for enhancing sintering using a sintering trolley involves multiple air boxes arranged along the trolley's running direction. Based on the differences in combustion state, melting state, and permeability of the sintering material layer corresponding to each air box location during the sintering process, and under the condition that the overall exhaust capacity of the sintering machine is basically stable, an air volume weighting factor is introduced to non-uniformly and tieredly distribute the air volume of each air box, using the total average sintering air volume as a benchmark. This air volume weighting factor is correlated with dimensionless melting state parameters, dimensionless vertical sintering speed parameters, and dimensionless material layer permeability parameters. This achieves dynamic matching between the air supply volume of each air box and the material layer state, ensuring that the sintering material layer corresponding to different air box locations receives an air volume supply matching its state, thereby improving the temperature distribution and melting state of the sintering material layer. The specific steps include the following:

[0047] Step 1: Based on the operating conditions of the sintering machine, obtain data on the material layer temperature distribution, combustion front position, and material layer pressure difference corresponding to each wind box position; set N wind boxes sequentially along the trolley travel direction of the sintering machine, and number each wind box sequentially as i=1, 2…N along the trolley travel direction;

[0048] Step 2: Calculate the dimensionless molten state parameter M corresponding to each windbox position based on the above data. i Dimensionless vertical sintering rate parameter V i and the dimensionless material layer permeability parameter K i ;

[0049] Dimensionless molten state parameter M iThe molten state index (MQI) is obtained by dimensionless transformation of the sintering state index corresponding to the i-th wind box position. i The thermal intensity used to characterize the material layer at this location reaching a melting threshold temperature along its thickness is defined as follows:

[0050]

[0051] in, Let z represent the temperature distribution along the thickness direction of the sintered material layer corresponding to the i-th wind box position, z be the coordinate of the material layer thickness direction, H be the material layer thickness, and Tm be the effective melting threshold temperature; the dimensionless melting state parameter is defined as:

[0052]

[0053] Dimensionless vertical sintering rate parameter V i It is determined by the ratio of the vertical sintering rate at the corresponding wind box position to the overall average vertical sintering rate; where the vertical sintering rate v at the i-th wind box position is... i It is determined by the rate of change of the position of the combustion front along the layer thickness direction, that is:

[0054]

[0055] in, This indicates the position of the combustion front in the sintering layer at the i-th wind box location along the thickness direction of the layer; the corresponding dimensionless vertical sintering velocity parameter is:

[0056]

[0057] Dimensionless material layer air permeability parameter K i The permeability characteristic index of the material layer is used for characterization; the permeability characteristic index k of the material layer at the i-th wind box position is... i Determined according to the following formula:

[0058]

[0059] Where A is the effective exhaust area, h is the bed height, and ΔP i The pressure difference between the bed and the corresponding wind box location; the dimensionless material bed permeability parameter is defined as:

[0060] ;

[0061] Step 3: Calculate the air volume weighting factor W for each air box based on the above parameters. i It is then normalized to meet the total air volume conservation constraint; air volume weighting factor W i This can be expressed as a weighted function of the dimensionless parameters mentioned above:

[0062]

[0063] in, , , Here are the weighting coefficients: α = 0.5, b = 0.3, c = 0.2;

[0064] Step 4: Determine the target air volume Q for each air box based on the air volume weighting factor. i The total average sintering air volume of the sintering machine under given operating conditions is Q. avg Then the sintering air volume Q of the i-th wind box i Air volume weighting factor W i It is determined that the relationship is as follows:

[0065] Q i =Q avg *W i ;

[0066] Step 5: By adjusting the valve openings of each air box, the actual air volume of each air box gradually approaches the corresponding target air volume. Corrective adjustments are made when the deviation exceeds the set range to achieve a tiered distribution of air volume. Under the premise of ensuring stable overall sintering capacity of the sintering machine, the sintering air volume of each air box is redistributed, so that changes in the sintering air volume of each air box reflect adjustments in the relative distribution relationship, rather than simply increasing or decreasing the total air volume. The air volume weighting factor of each air box should satisfy the following overall balance constraints:

[0067] ;

[0068] Step Six: During the sintering process, the parameters are dynamically updated according to the changes in the state of the material layer, and the air volume distribution is adjusted in real time accordingly.

[0069] Under typical sintering conditions, the air volume weighting factor W obtained from the above calculations is... i The air box number exhibits regional variation characteristics across the entire air box area; the calculated air volume weighting factor and corresponding sintering air volume show the following multi-regional distribution characteristics:

[0070] Region 1 (Top 10%N): → ;

[0071] Region 2 (10%~30%N): → ;

[0072] Region 3 (30%~70%N): → ;

[0073] Region 4 (70%~80%N): → ;

[0074] Region 5 (80%~95%N): → ;

[0075] Region Six (N after 95%): → .

Claims

1. A method for enhancing sintering using a cascade air supply system on a sintering trolley, characterized in that, In the multiple air boxes set along the trolley running direction of the sintering machine, based on the differences in combustion state, melting state, and permeability of the sintering material layer corresponding to each air box position during the sintering process, and under the condition that the overall exhaust capacity of the sintering machine is basically stable, an air volume weighting factor is introduced to distribute the air volume of each air box non-uniformly and in stages, with the total average sintering air volume as the benchmark. The air volume weighting factor is related to the dimensionless melting state parameter, the dimensionless vertical sintering speed parameter, and the dimensionless permeability parameter of the material layer, so as to achieve dynamic matching between the air supply volume of each air box and the state of the material layer, so that the sintering material layer corresponding to different air box positions receives an air volume supply that matches its state, thereby improving the temperature distribution and melting state of the sintering material layer.

2. The cascade air supply method for enhanced sintering using a sintering trolley according to claim 1, characterized in that, Specifically, the steps include the following: Step 1: Based on the operating conditions of the sintering machine, obtain data on the material layer temperature distribution, combustion front position, and material layer pressure difference corresponding to each air box location; Step 2: Calculate the dimensionless molten state parameter M corresponding to each windbox position based on the above data. i Dimensionless vertical sintering rate parameter V i and the dimensionless material layer permeability parameter K i ; Step 3: Calculate the air volume weighting factor W for each air box based on the above parameters. i And normalize it to meet the total air volume conservation constraint; Step 4: Determine the target air volume Q for each air box based on the air volume weighting factor. i ; Step 5: By adjusting the opening of each air box valve, the actual air volume of each air box gradually approaches the corresponding target air volume, and correction adjustment is made when the deviation exceeds the set range, so as to achieve the step distribution of air volume; Step Six: During the sintering process, the parameters are dynamically updated according to the changes in the state of the material layer, and the air volume distribution is adjusted in real time accordingly.

3. The cascade air supply method for enhanced sintering using a sintering trolley according to claim 2, characterized in that, In step one, N air boxes are sequentially set up along the trolley running direction in the sintering machine, and each air box is numbered i=1, 2...N along the trolley running direction.

4. The cascade air supply method for enhanced sintering using a sintering trolley according to claim 3, characterized in that, In step two, the dimensionless molten state parameter M i The dimensionless molten state index of the sintered material layer corresponding to the i-th wind box position is obtained; Melt State Index (MQI) i The thermal intensity used to characterize the material layer at this location reaching a melting threshold temperature along its thickness is defined as follows: in, Let z represent the temperature distribution along the thickness direction of the sintered material layer corresponding to the i-th wind box position, z be the coordinate of the material layer thickness direction, H be the material layer thickness, and Tm be the effective melting threshold temperature; the dimensionless melting state parameter is defined as: Dimensionless vertical sintering rate parameter V i It is determined by the ratio of the vertical sintering rate at the corresponding wind box position to the overall average vertical sintering rate; where the vertical sintering rate v at the i-th wind box position is... i It is determined by the rate of change of the position of the combustion front along the layer thickness direction, that is: in, This indicates the position of the combustion front in the sintering layer at the i-th wind box location along the thickness direction of the layer; the corresponding dimensionless vertical sintering velocity parameter is: Dimensionless material layer air permeability parameter K i The permeability characteristic index of the material layer is used for characterization; the permeability characteristic index k of the material layer at the i-th wind box position is... i Determined according to the following formula: Where A is the effective exhaust area, h is the bed height, and ΔP i The pressure difference between the bed and the corresponding wind box location; the dimensionless material bed permeability parameter is defined as: 。 5. The cascade air supply method for enhanced sintering using a sintering trolley according to claim 3, characterized in that, In step three, the air volume weighting factor W i This can be expressed as a weighted function of the dimensionless parameters mentioned above: in, , , Let be the weight coefficient, and satisfy... .

6. The cascade air supply method for enhanced sintering using a sintering trolley according to claim 5, characterized in that, ɑ=0.4-0.6, b=0.2-0.4, c=0.1-0.

3.

7. The cascade air supply method for enhanced sintering using a sintering trolley according to claim 3, characterized in that, In step four, the total average sintering air volume of the sintering machine under given operating conditions is Q. avg Then the sintering air volume Q of the i-th wind box i Air volume weighting factor W i It is determined that the relationship is as follows: Q i =Q avg *W i 。 8. The cascade air supply method for enhanced sintering using a sintering trolley according to claim 3, characterized in that, In step five, under the premise of ensuring the overall ventilation capacity of the sintering machine remains stable, the sintering air volume of each air box is redistributed so that the change in the sintering air volume of each air box reflects the adjustment of the relative distribution relationship, rather than simply increasing or decreasing the total air volume. The air volume weighting factor of each air box should satisfy the following overall balance constraint conditions: 。

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