Coal blending optimization method based on inert capacity of cohesive coal

Abstract

The invention relates to a coal blending optimization method based on coked coal inert capacity, which can improve the coke quality prediction accuracy, improve the inert component utilization efficiency, reduce the coke coal blending cost and optimize the coal blending method by taking inert capacity as a third factor by establishing an industrial experience-based inert capacity evaluation system. The coal blending technology is promoted to be converted from'empirical 'to'precise', and iron and steel enterprises can deal with fluctuation of cohesive coal resources. According to the method, on the basis of long-term accumulation and analysis of industrial data, differential calculation parameters are provided according to caking contribution values of caking coal (fat coal, coking coal, 1 / 3 coking coal and gas coal) with different characteristics in a coal blending scheme, the total inert capacity Q of the caking coal in coal blending is controlled to be within the range of 19.0-20.0, accurate improvement is achieved, the coke quality is predicted, and the coal blending efficiency is improved. And the waste of cohesiveness is avoided.

Description

Technical Field

[0001] This invention relates to the field of coking coal quality evaluation technology, and in particular to a method for optimizing coking coal blending based on the inertia capacity of caking coal. Background Technology

[0002] In the steel industry, coke is the core raw material for blast furnace ironmaking, and its quality directly determines the smooth operation of the blast furnace, ironmaking energy consumption, and the quality of molten iron. Coal blending technology is a key means of controlling coke quality. Caking coals (such as fat coal, coking coal, gas coal, and 1 / 3 coking coal) are core components of coal blends, and their caking ability is a key indicator determining the feasibility of coal blending schemes and the strength of coke. Therefore, establishing a scientific evaluation system for caking coals has always been a key focus of technological research and development in the coking industry. For a long time, the industry has generally used traditional indicators such as the caking index (G value), maximum coke layer thickness (Y value), Oya expansion (b value), and free expansion index (FSI) to evaluate the caking performance of caking coals. The caking index quantifies the caking ability of coal by measuring the abrasion resistance of coke after mixing coal samples with standard anthracite; the thickness of the plastic layer reflects the quantity and viscosity characteristics of the plastic mass formed during the heating process; and the Oya expansion characterizes the fluidity and expansion capacity of the plastic mass through the volume expansion rate of the coal sample under specific conditions. These indicators have played a crucial role in coal blending practices. For example, by controlling the caking index to ≥65 and the plastic layer thickness to 13-18mm in the blended coal, the cold strength of coke (M40≥80%) can be initially guaranteed. However, with the increasing demand for high-quality coke in the steel industry (e.g., the requirement for coke hot performance CRI≤25% and CSR≥65% due to the trend towards larger blast furnaces), the limitations of traditional evaluation methods have become increasingly apparent, and their prediction bias for the quality of coke after coking from caking coal has become increasingly significant. The core problem is that traditional indicators only evaluate the caking capacity of caking coal itself, while ignoring the interaction between caking coal and inert components (such as lean coal, poor coal, and semi-lean coal) during the coking process—that is, the ability of caking coal to accommodate inert components and maintain its overall caking performance (inertia tolerance performance). Industrial production data shows that when the amount of inert components added to the coal blend is 10%-15%, even if the G and Y values ​​of the two coals in the blend are similar (e.g., the G value of coking coal A and coking coal B are both 85±2, and the Y value is both 20±1mm), the final coke's M40 can differ by 4%-6% and the CSR can differ by 5%-7% when different types of coal are used.

[0003] To address this issue, researchers both domestically and internationally have begun to introduce "inertia tolerance" as a supplementary indicator for evaluating caking coal. Inertia tolerance is defined as the ability of caking coal to maintain its plastic body binding capacity and promote coke densification in the presence of inert components during high-temperature coking (400-1000℃). Its core evaluation dimensions include the saturated capacity of inert components (i.e., the maximum proportion of inert components added when caking coal can still guarantee the required coke strength) and the interfacial bonding strength between the plastic body and inert components (characterized by the thickness and density of the binding phase surrounding the inert particles in the coke microstructure). Existing research has preliminarily explored the inertia tolerance of caking coal using small-scale laboratory setups. For example, it has been found that the saturated capacity of inert components in coking coal is generally higher than that in gas coal, and the interfacial bonding strength of fat coal is better than that of 1 / 3 coking coal. However, current research is still in the experimental stage and faces three major limitations: First, the experimental scale is disconnected from industrial production. The coal sample size and heating rate used in the laboratory differ significantly from those in industrial coke ovens, making it impossible to directly apply the experimentally measured inertia parameters to industrial coal blending. Second, the research subjects lack specificity. Existing studies mostly focus on the inertia of single coal types, without considering the differences in the caking characteristics of commonly used coking coals such as bituminous coal, coking coal, and gas coal / 1 / 3 coking coal (e.g., bituminous coal has a large amount of plasticity but poor thermal stability, while gas coal / 1 / 3 coking coal has high volatile matter and large fluctuations in caking properties) to conduct a systematic evaluation. Third, the correlation mechanism between inertia and coal blending schemes is unclear. A quantitative relationship between inertia parameters and coal blending ratios and coke quality has not yet been established, making it impossible to provide precise guidance for industrial coal blending. These limitations make it difficult to implement inertia performance evaluation, and traditional coal blending methods still rely on empirical adjustments, posing a significant challenge to the stability of coke quality.

[0004] This invention targets the four most widely used types of caking coal in industrial coal blending—coking coal, bituminous coal, 1 / 3 coking coal, and gas coal. It conducts an evaluation of the inertia capacity based on industrial production experience. The core objective is to use the inertia capacity of caking coal as a third factor to correct and optimize coal blending schemes, overcoming the shortcomings of traditional evaluation systems such as large prediction bias and poor blending stability. Summary of the Invention

[0005] This invention provides a coal blending optimization method based on the inertia capacity of caking coal. By establishing an inertia capacity evaluation system based on industrial experience, it can improve the accuracy of coke quality prediction, increase the utilization efficiency of inert components, and reduce coke blending costs. Simultaneously, it fills the gap in industrial-scale inertia capacity research, overcomes the technical bottleneck of the disconnect between laboratory research and industrial application, and uses inertia capacity as a third factor to optimize coal blending methods. This promotes the transformation of coal blending technology from "empirical" to "precision-based," helping steel enterprises cope with fluctuations in caking coal resources (such as alternating use of coal types from different mining areas), ensuring stable coke quality, and thus supporting the efficient, low-consumption, and low-carbon operation of blast furnaces. Furthermore, this invention can be directly applied to the adjustment of coal blending schemes in coking enterprises and provides a new evaluation standard for the efficient utilization of caking coal resources, showing broad application prospects.

[0006] To achieve the above objectives, the present invention employs the following technical solution: A coal blending optimization method based on the inertia capacity of caking coal includes the following steps: 1) The inertia capacity of a single type of caking coal is set according to formula (1): The inertness capacity of a single type of caking coal is Q = k1*α + k2*A + k3*B (1); In formula (1): α is the decrease in the expansion degree of O-A caused by adding 1% of inert material to caking coal; A represents the mass fraction of inert material added when the caking coal reaches a state of shrinkage only. B represents the length of the overlap mark between the cohesive coal and the inert material. For coking coal, 1 / 3 coking coal and gas coal with different bonding properties, the values ​​of coefficients k1, k2 and k3 are shown in Table 1 below. 2) The total inertia capacity of caking coal is set according to formula (2), and the total inertia capacity Q of caking coal in the coal blend is controlled. 总 It falls within the range of 19.0 to 20.0; Total inert capacity Q of caking coal 总 =2 * Fat Coal Proportion% * Q 肥 +1.5*coking coal ratio%*Q 焦 +1.2*1 / 3 coking coal proportion %*Q 1 / 3焦 +1.2*Gas-coal ratio%*Q 气 (2).

[0007] Furthermore, in controlling coal blending, the inertia capacity of the selected single type of caking coal falls within the following range: The inertness tolerance of coking coal, Q 肥 : 15.0 to 22.0 range; Coking coal's inertness capacity Q焦 : 10.0 to 15.0 range; 1 / 3 coking coal or gas coal Q 1 / 3焦 Or Q 气 : 5.0 to 8.0 range.

[0008] Compared with existing technologies, the beneficial effects of this invention are: 1) The core advantage of the coal blending optimization method based on the inertia capacity of caking coal of the present invention lies in relying on the long-term accumulation and analysis of industrial data. Based on the specific role and contribution value of caking coal with different characteristics in the coal blending scheme, the method provides differentiated calculation parameters, so that the coal blending results are closely aligned with the actual production scenario, greatly improving the prediction accuracy of coke quality and coal blending effect, and providing a more targeted basis for subsequent coal blending scheme adjustments.

[0009] 2) This invention provides a coal blending optimization method based on the inertia capacity of caking coal, effectively breaking through the traditional reliance on empirical judgment or laboratory data in coal blending. By constructing an industrial experience-oriented inertia evaluation system to optimize the coal blending structure, the utilization rate of inert components can be directly improved, while reducing coal blending costs, ultimately achieving the synergistic optimization goal of stable coke quality and improved production efficiency.

[0010] 3) The present invention provides a coal blending optimization method based on the inertia capacity of caking coal. Inertia capacity is taken as the core factor for optimizing coal blending method. It effectively copes with the fluctuation of caking coal resources in different mining areas, ensures the stability of coke quality, and establishes a new evaluation system for the efficient utilization of caking coal. It provides technical support for the efficient, low-consumption and low-carbon operation of blast furnace from the source of coking, and extends the benefits of green production.

[0011] The present invention provides a coal blending optimization method based on the inertia capacity of cohesive coal. The calculation method is simple, scientific, and easy to operate, and has the potential for wide application. Detailed Implementation

[0012] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0013] A coal blending optimization method based on the inertia capacity of cohesive coal specifically includes: 1. The main factors in the evaluation method for the inertia capacity of cohesive coal of the present invention are: O-A expansion degree-inertia capacity and interfacial bonding capacity, specifically: (1) The expansion degree of Oa-A and the inert capacity include the inert rate (the decrease in expansion degree of Oa-A caused by adding 1% inert material to caking coal, defined as α) and the maximum inert amount (the mass fraction of inert material added when caking coal reaches the shrinkage state, defined as A). (2) Interface bonding ability (the length of the overlap mark between the cohesive coal and the inert material, defined as B).

[0014] 2. Based on the integrated analysis of industrial test data, the inertia tolerance of caking coal is set as follows: The inert capacity of a single type of caking coal is Q = k1*α + k2*A + k3*B (1) For coking coal, 1 / 3 coking coal and gas coal with different bonding properties, the values ​​of coefficients k1, k2 and k3 are shown in Table 1.

[0015] 3. Furthermore, in coal blending, the inertia capacity of the selected single type of caking coal should be within the following range: The inertness tolerance of coking coal, Q 肥 : 15.0~22.0 range; Coking coal's inertness capacity Q 焦 : 10.0~15.0 range; 1 / 3 coking coal or gas coal Q 1 / 3焦 Or Q 气 Range: 5.0~8.0.

[0016] 4. Furthermore, it is recommended to control the total inertia capacity Q of caking coal in the coal blend. 总 (=2 * coking coal ratio (%) * Q) 肥 +1.5 * coking coal ratio (%) * Q 焦 +1.2*1 / 3 coking coal proportion (%)*Q 1 / 3焦 +1.2 * Gas-coal ratio (%) * Q 气 A value between 19.0 and 20.0 will not cause waste of adhesiveness.

[0017] [Example]: This embodiment provides a coal blending optimization method based on the inertia capacity of coking coal, which is applied to the optimization of the coal blending and coking scheme of a certain enterprise. The current coal blending structure of the enterprise is: 40% coking coal, 26% fat coal, 30% 1 / 3 coking coal, and 14% lean coal.

[0018] Two types of coking coal, fat coal, and 1 / 3 coking coal with similar indicators were selected from the company's coal bunker as controls, and one type of lean coal was selected for coal quality index testing. The results are shown in Table 2. Table 2 Coal quality indicators of the examples As can be seen from Table 2 above, the selected coking coals used as controls—coking coal group (JM1, JM2), fat coal group (FM1, FM2), and 1 / 3 coking coal group (1 / 3JM1, 1 / 3JM2)—are very similar in terms of traditional coal quality indicators, and their coking properties (G value) are basically the same. Therefore, they cannot express the contribution of the control coals to coking properties and inertness in coal blending and coking.

[0019] Therefore, the O.A. dilatation method was further used to determine the inertia capacity of the above-mentioned coal types, and the interfacial bonding capacity between the six types of caking coal and lean coal was determined. The results are shown in Table 3. Table 3. Indicators of Inertia Capacity and Interfacial Bonding Capacity of Single Coal Types in Examples The inertia capacity of caking coal was evaluated, and the results are shown in Table 4: Table 4 Evaluation Table of Inert Capacity of Single Coal Type in Examples Table 3 clearly shows the inertia capacity of caking coal. Small-scale coking tests were conducted to verify the impact of inertia capacity on coking performance. The coal blending scheme is shown in Table 5, and the coking quality indicators are shown in Table 6. Table 5 Coal blending schemes for the examples Table 6. Coke quality in the examples The results in Table 6 show that the total inertia capacity value Q of caking coal in the coal blend is... 总 When the inertia value is controlled around 20.0, the inertia capacity of caking coal is maximized, resulting in the highest CSR value for coke (e.g., in Example 5) and better coke quality. However, inertia values ​​>20.0 result in wasted inertia capacity, and coke quality does not show an improved trend. In such cases, lean coal or semi-lean coal with stronger inertia can be added to the coal blend, achieving cost reduction while ensuring coke quality.

[0020] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A coal blending optimization method based on the inertia capacity of caking coal, characterized in that, Includes the following steps: 1) The inertia capacity of a single type of caking coal is set according to formula (1): The inert capacity of a single type of caking coal is Q = k1*α + k2*A + k3*B (1); In formula (1): α is the decrease in the expansion degree of O-A caused by adding 1% of inert material to caking coal; A represents the mass fraction of inert material added when the caking coal reaches a state of shrinkage only. B represents the length of the overlap mark between the cohesive coal and the inert material. For coking coal, 1 / 3 coking coal and gas coal with different bonding properties, the values ​​of coefficients k1, k2 and k3 are shown in Table 1 below; 2) The total inertia capacity of caking coal is set according to formula (2), and the total inertia capacity Q of caking coal in the coal blend is controlled. 总 It falls within the range of 19.0 to 20.0; Total inert capacity Q of caking coal 总 =2 * coking coal ratio % * Q 肥 +1.5*coking coal ratio%*Q 焦 +1.2*1 / 3 coking coal proportion %*Q 1 / 3焦 +1.2*Gas-coal ratio%*Q 气 (2).

2. The coal blending optimization method based on the inertia capacity of caking coal according to claim 1, characterized in that, In controlled coal blending, the inertia capacity of the selected single type of caking coal falls within the following range: The inertness capacity Q of coking coal 肥 : 15.0 to 22.0 range; The inertness capacity Q of coking coal 焦 : 10.0 to 15.0 range; 1 / 3 coking coal or gas coal Q 1 / 3焦 Or Q 气 : 5.0 to 8.0 range.

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