Special coal resource evaluation method

Abstract

The invention discloses a special coal resource evaluation method, which comprises the following steps of: constructing a special coal geological evaluation index system, analyzing the influence of different indexes on the productivity of coking, direct liquefaction and gasification processes, endowing the geological indexes with weights by using a multi-level analysis method, and performing trapezoidal membership function degree evaluation on each index by using a fuzzy comprehensive mathematical evaluation method. And calculating comprehensive scores of coking, direct liquefaction and gasification of main coal seams in different mining areas. The method has the beneficial effects that the mining value and characteristics of the coal mine can be accurately determined, the coal mine is helped to formulate an optimal mining process, and the economic benefit of coal mining is improved.

Description

Technical Field

[0001] This invention relates to the field of coal chemical technology, and specifically to a method for evaluating special coal resources. Background Technology

[0002] Ningxia, as one of the key coal-producing areas in China, possesses favorable conditions for the development of its coal chemical industry due to its excellent transportation infrastructure and relatively low energy costs. Currently, Ningxia's coal chemical industry has achieved a certain degree of industrial agglomeration, with the Ningdong Energy and Chemical Base becoming one of the largest coal chemical bases in the country. The development of coal chemical technology is of great significance to Ningxia's economic and social development. However, existing evaluation methods lack differentiated indicator systems for different coal chemical processes (such as coking, direct liquefaction, and gasification), resulting in an inability to accurately match process requirements.

[0003] Based on this need, and with the clean and efficient utilization of coal as the research goal, key geological indicators affecting the coal coking, direct liquefaction, and gasification processes were selected. The influence mechanism of different key geological indicators on coal chemical production capacity was clarified. Based on a thorough survey of the coal quality requirements of different processes in Ningxia coal chemical enterprises, and combined with physical simulation and numerical simulation, an evaluation index system and evaluation method for coal resources used in coking, direct liquefaction, and gasification were constructed. Resource evaluation was carried out to preliminarily clarify the resources available for special coal uses. Summary of the Invention

[0004] This invention addresses the problem that existing methods for evaluating special-use coal resources lack the ability to accurately evaluate the characteristics of a specific coal seam, and provides a method for evaluating special-use coal resources.

[0005] To achieve the above-mentioned technical objectives, the technical solution adopted by the special coal resource evaluation method of the present invention includes the following specific evaluation methods: Step 1: Collect coal samples from different regions and pre-process the coal samples; The second step involves using physical and numerical simulations to analyze the impact of geological indicators on coal chemical production capacity under different technological conditions; analyzing the matching relationship and coupling mechanism between coal type, geological indicators, and coal chemical production capacity; and screening out geological indicators that affect the production capacity of coking, direct liquefaction, and gasification processes. Step 3: Based on the selected geological indicators, construct an evaluation index system for coal resources used in coking, direct liquefaction, and gasification; Step 4: Assign weights to the geological indicators in the indicator system using multi-level analysis. Step 5: Conduct coal petrography and coal quality analysis tests on the collected coal samples. Combine the coal quality analysis data collected from previous geological exploration stages, incorporate the coal petrography and coal quality indicators of the coal seam into the indicator system determined by the evaluation method, and use the fuzzy mathematics comprehensive evaluation method to evaluate the trapezoidal membership function degree of each indicator and calculate the comprehensive score.

[0006] Preferably, the coal sample pretreatment includes crushing, screening, mixing, reduction and drying.

[0007] Preferably, the geological indicators for evaluating coal resources used in coking include maximum vitrinite reflectance, vitrinite content, moisture, ash, volatile matter, sulfur, plastic layer index, and caking index.

[0008] Preferably, the geological indicators for evaluating direct liquefaction resources include vitrinite maximum reflectance, inertinite content, moisture, ash content, volatile matter, hydrogen-to-carbon atomic ratio, and Hardgrove grindability index.

[0009] Preferably, the geological indicators for evaluating coal resources used in gasification include moisture, ash, volatile matter, sulfur, ash fusion properties, and thermal stability.

[0010] Preferably, the multi-level analysis method assigns weights to geological indicators, and the specific steps are as follows: Step 1: Establish a hierarchical structure model Step 2: Construct the judgment matrix; Step 3: Hierarchical single sorting and consistency check; Step 4: Overall hierarchical ranking and consistency check; Step 5: Calculate the weights of each indicator in the resource evaluation index system for coking coal, direct liquefaction coal, and gasification coal.

[0011] Preferably, when evaluating coking coal, suitable coking coal includes 1 / 3 coking coal, fat coal, coking coal, and lean coal, while gas coal and gas-fat coal can be used as coking blending coal.

[0012] Preferably, the comprehensive score evaluation of coking coal resources is divided into the following categories: comprehensive score > 0.60 is high-quality coking coal resources, comprehensive score 0.50-0.60 is medium-quality coking coal resources, and comprehensive score < 0.50 is poor-quality coking coal resources.

[0013] Preferably, the comprehensive score evaluation of direct liquefaction coal resources is divided into the following categories: comprehensive score > 0.70 is high-quality direct liquefaction coal resources, comprehensive score 0.50-0.70 is medium-quality direct liquefaction coal resources, and comprehensive score < 0.50 is unsuitable for direct liquefaction coal resources.

[0014] Preferably, the comprehensive score evaluation of coal resources for gasification is divided into the following categories: comprehensive score > 0.80 is high-quality coal resources for gasification, comprehensive score 0.60-0.80 is medium-quality coal resources for gasification, and comprehensive score < 0.60 is unsuitable coal resources for gasification.

[0015] The beneficial effects of this invention lie in constructing a geological evaluation index system for special coal applications, analyzing the impact of different indicators on the production capacity of coking, direct liquefaction, and gasification processes, assigning weights to geological indicators using a multi-level analysis method, and employing a fuzzy comprehensive mathematical evaluation method to evaluate the trapezoidal membership function degree of each indicator, thereby calculating the comprehensive scores for coking, direct liquefaction, and gasification of major coal seams in different mining areas. This allows for the accurate determination of the mining value and characteristics of coal mines, helping coal mines formulate optimal mining processes and improve the economic benefits of coal mining. Detailed Implementation

[0016] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit this specification.

[0017] A method for evaluating special-use coal resources employs physical and numerical simulations to elucidate the geological control mechanisms for the clean and efficient utilization of special-use coals. It constructs an evaluation index system and method for coal resources used in coking, direct liquefaction, and gasification, and assesses the potential for clean and efficient utilization of coal in the chemical industry. The specific evaluation method is as follows: Step 1: Collect coal samples from different regions and pre-process the coal samples; The second step involves using physical and numerical simulations to analyze the impact of geological indicators on coal chemical production capacity under different technological conditions; analyzing the matching relationship and coupling mechanism between coal type, geological indicators, and coal chemical production capacity; and screening out geological indicators that affect the production capacity of coking, direct liquefaction, and gasification processes. Step 3: Based on the selected geological indicators, construct an evaluation index system for coal resources used in coking, direct liquefaction, and gasification; Step 4: Assign weights to the geological indicators in the indicator system using multi-level analysis. Step 5: Conduct coal petrography and coal quality analysis tests on the collected coal samples. Combine the coal quality analysis data collected from previous geological exploration stages, incorporate the coal petrography and coal quality indicators of the coal seam into the indicator system determined by the evaluation method, and use the fuzzy comprehensive mathematical evaluation method to evaluate the trapezoidal membership function degree of each indicator and calculate the comprehensive score.

[0018] Coal sample pretreatment includes crushing, screening, mixing, reduction and drying.

[0019] The multi-level analysis method assigns weights to geological indicators, and the specific steps are as follows: Step 1: Establish a hierarchical structure model Step 2: Construct the judgment matrix; Step 3: Hierarchical single sorting and consistency check; Step 4: Overall hierarchical ranking and consistency check; Step 5: Calculate the weights of each indicator in the resource evaluation index system for coking coal, direct liquefaction coal, and gasification coal.

[0020] When evaluating coal for coking, suitable coking coals include 1 / 3 coking coal, fat coal, coking coal, and lean coal. Gas coal and gas-fat coal can be used as coking blending coals. Geological indicators for evaluating coal resources for coking include maximum vitrinite reflectance, vitrinite content, moisture, ash, volatile matter, sulfur, plastic layer index, and caking index. Geological indicators for evaluating coal resources for direct liquefaction include maximum vitrinite reflectance, inertinite content, moisture, ash, volatile matter, hydrogen-to-carbon atomic ratio, and Hardgrove grindability index. Geological indicators for evaluating coal resources for gasification include moisture, ash, volatile matter, sulfur, ash fusibility, and thermal stability.

[0021] The comprehensive evaluation scores for coking coal resources are categorized as follows: a comprehensive score > 0.60 indicates high-quality coking coal resources, a comprehensive score between 0.50 and 0.60 indicates medium-quality coking coal resources, and a comprehensive score < 0.50 indicates poor-quality coking coal resources. Similarly, the comprehensive evaluation scores for direct liquefaction coal resources are categorized as follows: a comprehensive score > 0.70 indicates high-quality direct liquefaction coal resources, a comprehensive score between 0.50 and 0.70 indicates medium-quality direct liquefaction coal resources, and a comprehensive score < 0.50 indicates unsuitable direct liquefaction coal resources. Finally, the comprehensive evaluation scores for gasification coal resources are categorized as follows: a comprehensive score > 0.80 indicates high-quality gasification coal resources, a comprehensive score between 0.60 and 0.80 indicates medium-quality gasification coal resources, and a comprehensive score < 0.60 indicates unsuitable gasification coal resources.

[0022] The following is the resource evaluation index system for coking coal, direct liquefaction coal, and gasification coal: Table 1: Evaluation Index System for Coal Resources Used in Coking

[0023] Table 2 Evaluation Index System for Coal Resources Used in Direct Liquefaction

[0024] Table 3: Evaluation Index System for Coal Resources Used in Gasification

[0025] The following are the weights of resource evaluation indicators for coking coal, direct liquefaction coal, and gasification coal: Table 4: Weights of Evaluation Indicators for Coking Coal Resources

[0026] Table 5: Weights of Evaluation Indicators for Coal Resources Used in Liquefaction

[0027] Table 6: Weights of Evaluation Indicators for Coal Resources Used in Gasification

[0028] Based on the above evaluation methods, the main coal seams of the Rujigou and Hongdunzi mining areas are evaluated and analyzed, as detailed below: Example 1: This study evaluated five coal seams (Seam No. 2, Seam No. 3, Seam No. 4, Seam No. 5, and Seam No. 7) in the Baijigou coalfield of the Rujigou mining area. The moisture content of this coalfield is very low, with the main mineable coal seams having a moisture content (Mad) of 0.65%-0.80%. The ash yield of raw coal is 8.19-18.22%, with the lowest ash content in Seam No. 2 and the highest in Seam No. 5, showing an increasing trend in ash content from top to bottom. The volatile matter content of the coal is 8.23-9.72%, classifying it as ultra-low volatile matter coal, with a decreasing trend from top to bottom. The total sulfur content of raw coal is 0-0.54%, classifying it as ultra-low sulfur coal, with the lowest total sulfur content in Seam No. 2 in the Rujigou mining area, and little variation in sulfur content among the lower coal seams.

[0029] The dry basis high calorific value of raw coal in the Rujigou mining area is 29.41~33.60 MJ / kg, which is classified as extra-high calorific value coal. Among them, the No. 2 coal seam has the highest calorific value, at 33.60 MJ / kg.

[0030] Table 8: Coal Quality Characteristics of Major Coal Seams in Rujigou

[0031] The coal ash softening temperature of the Rujigou mining area is 1098-1218 ℃, which is considered to be low to medium softening temperature ash.

[0032] Example 2 The Hongdunzi mining area is located in the northeastern part of Ningxia Hui Autonomous Region, east of Yinchuan City, and is administratively under the jurisdiction of Xingqing District of Yinchuan City. The coal-bearing strata in the Hongdunzi mining area are the Taiyuan Formation of the Carboniferous System and the Shanxi Formation of the Permian System, with a total thickness of 172.67–226.95 m and an average of 189.86 m.

[0033] This study evaluated four coal seams—No. 2, No. 5, No. 8, and No. 9—in the Hongdunzi mining area. A comparison of the coal seam numbers for each mining area is shown in Table 9.

[0034] Table 9 Comparison of Coal Seam Numbers in Hongdunzi Mining Area

[0035] The four main coal seams, No. 2, No. 5, No. 8, and No. 9, in the Hongdunzi mining area were evaluated. The maximum vitrinite reflectance of each coal seam in the Hongdunzi mining area ranged from 0.654% to 0.714%, all belonging to the gas coal category. Their moisture content was low, ranging from 1.66% to 2.00%, with little variation in moisture content across the seams vertically. The ash yield was high across the area, ranging from 21.56% to 27.69%, with No. 2 coal seam having the highest ash yield at 27.69%. The volatile matter yield was also high, ranging from 38.94% to 40.90%, with little variation among the coal seams. The sulfur content varied considerably, with No. 2 and No. 5 coal seams having lower sulfur content, while No. 8 and No. 9 coal seams had higher sulfur content, classifying them as medium-to-high sulfur coals.

[0036] Table 10: Coal Quality Characteristics of Main Coal Seams in Hongdunzi Mining Area

[0037] Table 11: Microscopic Component Content of Major Coal Seams in Hongdunzi

[0038] The dry basis high calorific value of raw coal in the Hongdunzi mining area is 22.74~25.39 MJ / kg, which belongs to medium-high calorific value coal.

[0039] Under a weak reducing atmosphere, the softening temperature (ST) of coal ash is 1315 to >1450 ℃, generally >1450 ℃, which is classified as high softening temperature ash. The flow temperature (FT) of coal ash is 1356 to >1450 ℃, generally >1450 ℃, which is classified as high flow temperature ash.

[0040] Table 12: Characteristics of Coal Ash Fusibility in Hongdunzi Mining Area

Claims

1. A special coal resource evaluation method, the specific evaluation method is as follows: Step 1: Collect coal samples from different regions and pre-process the coal samples; The second step involves using physical and numerical simulations to analyze the impact of geological indicators on coal chemical production capacity under different technological conditions; analyzing the matching relationship and coupling mechanism between coal type, geological indicators, and coal chemical production capacity; and screening out geological indicators that affect the production capacity of coking, direct liquefaction, and gasification processes. Step 3: Based on the selected geological indicators, construct an evaluation index system for coal resources used in coking, direct liquefaction, and gasification; Step 4: Assign weights to the geological indicators in the indicator system using multi-level analysis. Step 5: Conduct coal petrography and coal quality analysis tests on the collected coal samples. Combine the coal quality analysis data from previous geological exploration stages, incorporate the coal petrography and coal quality indicators of the coal seam into the indicator system determined by the evaluation method, and use the fuzzy mathematics comprehensive evaluation method to evaluate the trapezoidal membership function degree of each indicator and calculate the comprehensive score.

2. The method for evaluating special coal resources according to claim 1, characterized in that: The coal sample pretreatment includes crushing, screening, mixing, reduction and drying.

3. The method for evaluating special coal resources according to claim 1, characterized in that: The geological indicators for evaluating coal resources used in coking include maximum reflectance of vitrinite, vitrinite content, moisture, ash, volatile matter, sulfur, plastic layer index, and caking index.

4. The method for evaluating special coal resources according to claim 1, characterized in that: The geological indicators for evaluating coal resources for direct liquefaction include maximum vitrinite reflectance, inertinite content, moisture, ash, volatile matter, hydrogen-to-carbon atomic ratio, and Hardgrove grindability index.

5. The method for evaluating special coal resources according to claim 1, characterized in that: The geological indicators for evaluating coal resources used in gasification include moisture, ash, volatile matter, sulfur, ash fusion properties, and thermal stability.

6. The method for evaluating special coal resources according to claim 1, characterized in that: The multi-level analysis method assigns weights to geological indicators, and the specific steps are as follows: Step 1: Establish a hierarchical structure model Step 2: Construct the judgment matrix; Step 3: Hierarchical single sorting and consistency check; Step 4: Overall hierarchical ranking and consistency check; Step 5: Calculate the weights of each indicator in the resource evaluation index system for coking coal, direct liquefaction coal, and gasification coal.

7. The method for evaluating special coal resources according to claim 1, characterized in that: When evaluating coking coal, suitable coking coal includes 1 / 3 coking coal, fat coal, coking coal, and lean coal. Gas coal and gas-fat coal can be used as coking blending coal.

8. The method for evaluating special coal resources according to claim 1, characterized in that: The comprehensive score evaluation of coking coal resources is divided into three categories: comprehensive score > 0.60 is high-quality coking coal resources, comprehensive score 0.50-0.60 is medium-quality coking coal resources, and comprehensive score < 0.50 is poor-quality coking coal resources.

9. The method for evaluating special coal resources according to claim 1, characterized in that: The comprehensive score evaluation of coal resources for direct liquefaction is divided into the following categories: a comprehensive score > 0.70 is considered high-quality coal resources for direct liquefaction, a comprehensive score between 0.50 and 0.70 is considered medium-quality coal resources for direct liquefaction, and a comprehensive score < 0.50 is considered unsuitable coal resources for direct liquefaction.

10. The method for evaluating special coal resources according to claim 1, characterized in that: The comprehensive score evaluation of coal resources for gasification is divided into three categories: a comprehensive score > 0.80 is considered high-quality coal resources for gasification, a comprehensive score between 0.60 and 0.80 is considered medium-quality coal resources for gasification, and a comprehensive score < 0.60 is considered coal resources unsuitable for gasification.

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