A method and system for evaluating the impact of reducing the converter iron ore ratio

Abstract

The application discloses a method and system for evaluating the influence of reducing the converter iron-steel ratio, and the method comprises the following steps: collecting the process indexes, unit material consumption and recovery of each process of steel rolling under the current iron-steel ratio; calculating the increased output of finished steel per ton of scrap steel under the current iron-steel ratio according to the metal material balance, and calculating the compensation cost required for the converter to increase one ton of scrap steel under the corresponding heat compensation mode; calculating the total benefit generated by increasing one ton of scrap steel based on the expected prices of finished steel and scrap steel; when the total benefit is positive, the amount of scrap steel is increased under the corresponding heat compensation mode of the converter. In order to reduce the influence of the cost of molten iron and the fixed cost of the steel rolling process as much as possible, the "ton of scrap steel benefit" is introduced, the total benefit generated by the increased scrap steel is calculated under the current consumption index, the total amount of main material consumption such as molten iron and the total amount of fixed cost are fixed values, and the influence of the main raw materials such as molten iron and the fixed cost of the steel rolling process is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of iron and steel metallurgy, and more particularly, to a method and system for evaluating the impact of reducing the iron-steel ratio of a converter. Background Art

[0002] During the converter smelting process, the oxidation of various elements in the molten iron generates a significant amount of chemical heat, necessitating the addition of a coolant to maintain the converter's thermal balance. Scrap steel, a common coolant, is used extensively in converters due to its economical efficiency. This is particularly true in the context of energy conservation and emission reduction. The scrap ratio in converters has been increasing annually, exceeding 20% ​​at many steel mills. To maintain converter thermal balance and further increase the scrap ratio, heat-generating materials containing carbon and silicon, as well as preheating scrap steel, are commonly used to compensate for this heat.

[0003] For integrated steel companies, the iron-steel ratio is a crucial indicator for management decision-making. The greatest economic benefit of a blast furnace lies in stable operation, ensuring a relatively stable molten iron output. Given limited molten iron resources, reducing the iron-steel ratio can increase steel production and generate economies of scale. However, when steel prices are low and companies are facing minimal profits or even losses, timely adjustments to the iron-steel ratio based on fluctuations in scrap and steel market conditions can yield greater economic benefits. Therefore, measuring the impact of the iron-steel ratio on profitability in the short term is particularly important.

[0004] To measure the impact of the iron-to-steel ratio or scrap ratio on profitability, relevant literature offers complex cost calculation models. For example, the domestic patent "Method, System, Equipment, and Medium for Determining the Most Economical Scrap Ratio in Converter Steelmaking" (CN115261546A) sets constraints on converter steelmaking process specifications and, based on a cost calculation model for input and output materials and energy, compares the changes in profitability under different scrap ratios to determine the most economical scrap ratio. These models require a large number of process parameters to provide data support for the cost calculation model. They generally only measure the cost changes in the steelmaking process and are unable to measure the impact on the overall profitability of the enterprise. Summary of the Invention

[0005] The present invention provides a method for evaluating the impact of reducing the iron-steel ratio of a converter, aiming to improve the above-mentioned problem.

[0006] The present invention is achieved by providing a method for evaluating the impact of reducing the converter iron-steel ratio, the method comprising the following steps:

[0007] (1) Statistics on process indicators, unit material consumption and recovery of each process of steel rolling under the current iron-steel ratio;

[0008] (2) Based on the metal material balance, calculate the increase in finished steel production ΔQ caused by adding one ton of scrap steel at the current iron-steel ratio 材 ,

[0009] (3) Calculate the compensation cost ΔC required to increase one ton of scrap steel when the converter adopts the corresponding heat compensation method;

[0010] (4) Calculate the total benefit ΔP generated by each additional ton of scrap steel based on the expected prices of finished steel and scrap steel;

[0011] (5) When the total benefit ΔP is positive, the amount of scrap steel used is increased using the corresponding converter heat compensation method.

[0012] Furthermore, the output of finished steel products ΔQ 材 The calculation formula is as follows:

[0013]

[0014] Where η 废钢 W is the scrap steel recovery rate of the converter during the smelting process under the current iron-steel ratio, 合金 is the unit steel alloy consumption of the product in the smelting process under the current iron-steel ratio, η 合金 is the alloy yield rate of the converter in the smelting process under the current iron-steel ratio, η 坯 is the molten steel billet rate in the continuous casting process under the current iron-steel ratio, η 材 It is the yield rate of ingot in the steel rolling process under the current iron-steel ratio.

[0015] Furthermore, the compensation cost ΔC required for adding one ton of scrap steel is composed of three parts: the heat compensation cost required for adding one ton of scrap steel under the current iron-steel ratio, the increased cost of material consumption required for adding one ton of scrap steel under the current iron-steel ratio, and the income generated by the increase in recycled materials brought about by adding one ton of scrap steel under the current iron-steel ratio.

[0016] Furthermore, the calculation formula of compensation cost ΔC is as follows:

[0017]

[0018] Where C 热补 W is the heat compensation cost required to add one ton of scrap steel to the current iron-steel ratio. ij is the consumption increment of the jth material required for the i-th process when one ton of scrap steel is added under the current iron-steel ratio, where the consumed materials include auxiliary materials and energy media, P ij is the expected price of the jth material required for the i-th process under the current iron-steel ratio, ΔQ ik To increase the output of the kth type of recycled material in the i-th process when one ton of scrap steel is added, η ik is the recovery rate of the kth recycled material in the i-th process, P ik is the expected price of the kth type of recycled material in the i-th process.

[0019] Furthermore, the calculation formula for the total benefit ΔP is as follows:

[0020]

[0021] Where, P 废钢 is the expected price of one ton of scrap steel, P 材 is the expected price of finished steel products.

[0022] Furthermore, when the total benefit ΔP is negative, the maximum expected scrap steel price allowed by increasing the amount of scrap steel used under the current expected price of finished steel is output.

[0023] The present invention is achieved by providing a system for evaluating the impact of reducing the converter iron-steel ratio, the system comprising:

[0024] The input unit, processing unit and output unit are connected in sequence.

[0025] The input unit is used to input the process indicators of each steel rolling process under the current iron-steel ratio, unit material consumption and recovery, expected prices of scrap steel, related materials of each process and finished steel products, and send them to the processing unit;

[0026] The processing unit evaluates, based on the above-mentioned method for evaluating the impact of reducing the converter iron-steel ratio, whether it is appropriate to increase the amount of scrap steel used under the corresponding converter heat compensation method under the current expected prices of finished steel and scrap steel, and sends the evaluation result to the output unit;

[0027] The output unit outputs the evaluation result of the processing unit;

[0028] Furthermore, when the evaluation result is unsuitable, the maximum expected scrap steel price allowed by increasing the amount of scrap steel used under the current expected price of finished steel is output.

[0029] Furthermore, the output unit is a display unit.

[0030] The present invention reduces the impact of fixed costs of main raw materials such as molten iron and the steel rolling process as much as possible, further improves the accuracy of calculating the benefits of reducing the iron-steel ratio, provides a more reliable evaluation method for enterprises on how to adjust the iron-steel ratio, and guides the production scheduling of the steel rolling system to obtain greater economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart of a method for evaluating the impact of reducing the converter iron-to-steel ratio on efficiency provided by an embodiment of the present invention;

[0032] Figure 2 A schematic structural diagram of a system for evaluating the impact of reducing the converter iron-steel ratio provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The specific implementation methods of the present invention will be further explained in detail below by describing the embodiments with reference to the accompanying drawings, so as to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0034] Affected by the heat balance, the adjustment of the iron-steel ratio in the converter process is limited, the fluctuation range of steel production under the same amount of molten iron is limited, and the total fixed cost of the steel rolling system remains basically unchanged; under the premise of unchanged product structure, the consumption indicators of raw materials, auxiliary materials, energy media, etc. in the steel rolling process in the short term also change slightly. Therefore, it is usually necessary to calculate the material consumption indicators and costs under different iron-steel ratios in the short term based on the current production data and cost statements, and then calculate the income of the change in steel production under different iron-steel ratios, and finally calculate the benefits of adjusting the iron-steel ratio. This method involves molten iron and fixed costs in the calculation process, and because they account for a large proportion of the cost weight, the calculation results are very likely to produce large deviations. The present invention uses a method such as heating agents or scrap steel preheating to maintain the thermal balance of the converter, increases the scrap steel ratio of the converter to further reduce the iron-steel ratio, and calculates the expected benefits of the steel rolling process after the process adjustment. In order to reduce the impact of molten iron costs and fixed costs of the steel rolling process as much as possible, the present invention introduces the concept of "benefit per ton of scrap steel", that is, only the total benefit generated by the increased scrap steel is calculated under the current consumption indicators. Under this calculation method, the total consumption of major materials such as molten iron and the total fixed costs are fixed values, avoiding the impact of major raw materials such as molten iron and fixed costs of the steel rolling process as much as possible.

[0035] Figure 1 A flow chart of a method for evaluating the impact of reducing the converter iron-to-steel ratio on efficiency provided by an embodiment of the present invention, the method comprising the following steps:

[0036] (1) Statistics on the process indicators, unit material consumption and recovery of each process of steel rolling under the current iron-steel ratio, among which the process indicators include: the scrap steel recovery rate η of the converter during the smelting process; 废钢 , Molten steel billet rate η in the continuous casting process 坯 , the billet yield rate η in the steel rolling process 材 And the alloy yield η of the converter during the smelting process 合金 The unit material consumption includes the unit molten steel alloy consumption W of the product in the smelting process. 合金 ;

[0037] (2) Based on the metal material balance, calculate the increase in finished steel production ΔQ caused by adding one ton of scrap steel at the current iron-steel ratio 材 , finished steel output ΔQ 材 The calculation formula is as follows:

[0038]

[0039] Where η 废钢W is the scrap steel recovery rate of the converter during the smelting process under the current iron-steel ratio, 合金 is the unit steel alloy consumption of the product in the smelting process under the current iron-steel ratio, η 合金 is the alloy yield rate of the converter in the smelting process under the current iron-steel ratio, η 坯 is the molten steel billet rate in the continuous casting process under the current iron-steel ratio, η 材 It is the yield rate of ingot in the steel rolling process under the current iron-steel ratio.

[0040] (3) Calculate the compensation cost ΔC required to increase one ton of scrap steel when the converter adopts the corresponding heat compensation method;

[0041] In the embodiment of the present invention, the compensation cost ΔC required for increasing one ton of scrap steel is composed of three parts: one part is the heat compensation cost required for increasing one ton of scrap steel; another part is the cost of the increased consumption of auxiliary materials such as slag and alloy and energy media; and another part is the income generated by the increase in recycled materials. The specific calculation formula of the compensation cost ΔC is as follows:

[0042]

[0043] Where C 热补 W is the heat compensation cost required to add one ton of scrap steel to the current iron-steel ratio. ij is the consumption increment of the jth material required for the i-th process when one ton of scrap steel is added under the current iron-steel ratio, where the consumed materials include auxiliary materials and energy media, P ij is the expected price of the jth material required for the i-th process under the current iron-steel ratio, ΔQ ik To increase the output of the kth type of recycled material in the i-th process when one ton of scrap steel is added, η ik is the recovery rate of the kth recycled material in the i-th process, P ik is the expected price of the kth type of recycled material in the i-th process.

[0044] (4) Based on the expected prices of finished steel and scrap steel, the total benefit ΔP generated by each additional ton of scrap steel is calculated. The calculation formula for the total benefit ΔP is:

[0045] ΔP=ΔQ 材 ·P 材 -P 废铁 -ΔC (3)

[0046] Where, P 废钢 is the expected price of one ton of scrap steel, P 材 is the expected price of finished steel products. Substituting formulas (1) to (2) into formula (3), the calculation formula for the total benefit ΔP is as follows:

[0047]

[0048] (5) When the total benefit ΔP is positive, the amount of scrap steel used is increased by using the corresponding converter heat compensation method. When the total benefit ΔP is negative, the maximum expected scrap steel price allowed for increasing the amount of scrap steel used is determined under the current expected price of finished steel products. When the current expected scrap steel price is higher than the maximum expected scrap steel price allowed, the amount of scrap steel used is not increased by using the corresponding converter heat compensation method.

[0049] When the total benefit ΔP>0, it indicates that under the expected price, the use of this converter heat compensation method to increase the amount of scrap steel and thus reduce the iron-steel ratio can generate benefits. The iron-steel ratio plan can be significantly lowered without worsening the converter smelting indicators to obtain greater benefits. Because the converter heat compensation cost of increasing scrap steel is high, when the total benefit ΔP<0, it does not mean that reducing the scrap steel ratio can increase benefits. The current converter heat balance conditions need to be re-evaluated.

[0050] Figure 2 A schematic diagram of a system for evaluating the impact of reducing the converter iron-steel ratio provided by an embodiment of the present invention is provided. For ease of illustration, only portions related to the embodiment of the present invention are shown. The system includes:

[0051] An input unit, a processing unit, and an output unit connected in sequence, wherein the output unit includes a display unit;

[0052] The input unit is used to input the process indicators of each steel rolling process under the current iron-steel ratio, unit material consumption and recovery, expected prices of scrap steel, related materials of each process and finished steel products, and send them to the processing unit;

[0053] The processing unit evaluates whether it is appropriate to increase the amount of scrap steel in the corresponding converter heat compensation method under the current expected prices of finished steel and scrap steel based on the above-mentioned evaluation method for reducing the converter iron-steel ratio on benefits, and sends the evaluation result to the output unit.

[0054] The output unit outputs the evaluation result of the processing unit, and the evaluation result is suitable or unsuitable. When the evaluation result is unsuitable, the maximum expected price of scrap steel allowed under the expected price of the current finished steel product is output.

[0055] In a 120t converter → billet continuous casting → bar production line, graphite balls are added to the converter as a heating agent to increase the scrap steel ratio and further reduce the iron-steel ratio. According to the calculation method of the present invention, the calculation steps of the scrap steel benefit per ton increased by reducing the iron-steel ratio are as follows: (1) The main consumption indicators of each process under the current iron-steel ratio are calculated as follows:

[0056]

[0057] (2) Calculate the additional output of one ton of scrap steel in each process based on the metal material balance:

[0058] Molten steel volume / ton Billet quantity / ton Rolling material volume / ton 0.938 / (1-0.0227*0.985)＝0.959 0.959*0.987＝0.947 0.947*1.010＝0.956

[0059] (3) Calculate the total expected cost ΔC for each process step, including the additional heat compensation cost, auxiliary materials such as slag materials, energy media, and scrap steel recycling costs required for adding one ton of scrap steel. To simplify the calculation, in the short term, the price fluctuations of alloy auxiliary materials are relatively small. When the amount of scrap steel adjustment is not large, the cost can be calculated based on the current iron-steel ratio. The current cost of each process step is as follows (all materials are priced excluding tax, the same below):

[0060]

[0061] It is calculated that the total cost of adding 1 ton of scrap steel in each process is:

[0062] ΔC=1*556.67+0.959*289.58+0.947*19.42+0.956*64.82=914.74 yuan

[0063] (4) The expected scrap steel price P 废钢 and finished steel price P 材 As a variable, the calculation formula for the total benefit ΔP generated by each additional ton of scrap steel is:

[0064] ΔP=ΔQ 材 ·P 材 -P 废钢 -ΔC=0.956P 材 -P 废钢 -914.74

[0065] (5) ΔP>0, the scrap price P is obtained 废钢 and finished steel price P 材 The relationship:

[0066] P 废钢 <0.956P 材 -914.74

[0067] That is, the method of using graphite ball heating agents to increase scrap steel. When the steel price is expected to drop to 4,000 yuan / ton, the calculated scrap steel price must be less than 2,906.26 yuan / ton to be effective. This provides data support for immediately adjusting the iron-steel ratio plan according to the expected scrap steel price and guiding production scheduling.

[0068] The present invention has been described exemplarily. Obviously, the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. A method for evaluating the impact of reducing the converter iron-steel ratio, characterized in that: The method comprises the following steps: (1) Statistics on process indicators, unit material consumption and recovery of each process of steel rolling under the current iron-steel ratio; (2) Based on the metal material balance, calculate the increase in finished steel production ΔQ caused by adding one ton of scrap steel at the current iron-steel ratio 材 , (3) Calculate the compensation cost ΔC required to increase one ton of scrap steel when the converter adopts the corresponding heat compensation method; (4) Calculate the total benefit ΔP generated by each additional ton of scrap steel based on the expected prices of finished steel and scrap steel; (5) When the total benefit ΔP is positive, the amount of scrap steel is increased by using the corresponding converter heat compensation method; Finished steel output ΔQ 材 The calculation formula is as follows: Where η 废钢 W is the scrap steel recovery rate of the converter during the smelting process under the current iron-steel ratio, 合金 is the unit steel alloy consumption of the product in the smelting process under the current iron-steel ratio, η 合金 is the alloy yield rate of the converter in the smelting process under the current iron-steel ratio, η 坯 is the molten steel billet rate in the continuous casting process under the current iron-steel ratio, η 材 It is the yield rate of ingot in the steel rolling process under the current iron-steel ratio; The compensation cost ΔC required to increase one ton of scrap steel is composed of three parts: the heat compensation cost required to increase one ton of scrap steel under the current iron-steel ratio, the cost of the increased material consumption required to increase one ton of scrap steel under the current iron-steel ratio, and the income generated by the incremental recycled materials brought about by the increase of one ton of scrap steel under the current iron-steel ratio. The calculation formula for compensation cost ΔC is as follows: Where C 热补 W is the heat compensation cost required to add one ton of scrap steel to the current iron-steel ratio. ij is the consumption increment of the jth material required for the i-th process when one ton of scrap steel is added under the current iron-steel ratio, where the consumed materials include auxiliary materials and energy media, P ij is the expected price of the jth material required for the i-th process under the current iron-steel ratio, ΔQ ik To increase the output of the kth type of recycled material in the i-th process when one ton of scrap steel is added, η ik is the recovery rate of the kth recycled material in the i-th process, P ik is the expected price of the kth type of recycled material in the i-th process; The calculation formula for the total benefit ΔP is as follows: Where, P 废钢 is the expected price of one ton of scrap steel, P 材 is the expected price of finished steel products.

2. The method for evaluating the impact of reducing the converter iron-steel ratio according to claim 1, wherein: When the total benefit ΔP is negative, the output is the maximum expected scrap steel price allowed by increasing the scrap steel usage under the current expected price of finished steel.

3. A system for evaluating the impact of reducing converter iron-steel ratio, characterized in that: The system comprises: The input unit, processing unit and output unit are connected in sequence. The input unit is used to input the process indicators of each steel rolling process under the current iron-steel ratio, unit material consumption and recovery, expected prices of scrap steel, related materials of each process and finished steel products, and send them to the processing unit; The processing unit evaluates whether it is appropriate to increase the amount of scrap steel under the corresponding converter heat compensation method under the current expected prices of finished steel and scrap steel based on the benefit impact evaluation method for reducing the converter iron-steel ratio as described in any one of claims 1 to 2, and sends the evaluation result to the output unit, which outputs the evaluation result of the processing unit.

4. The benefit impact assessment system for reducing converter iron-steel ratio according to claim 3, characterized in that: When the evaluation result is unsuitable, the maximum expected scrap steel price allowed by increasing the amount of scrap steel used under the current expected price of finished steel is output.

5. The benefit impact assessment system for reducing converter iron-steel ratio according to claim 3, characterized in that: The output unit is a display unit.

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