神府南部矿区低阶煤化学组成与工艺性质:特征、关系与实践

Chemical compositions and technological properties of low-rank coals in the south Shenfu mining area: Characteristics, relationship and practice

  • 摘要: 煤炭分质利用是契合其高效、清洁与绿色发展趋势的必然途径,而了解煤的基本化学组成与关键工艺性质是实现煤炭资源分级分质利用的基础。陕西神府南部矿区煤炭储量丰富,是西部重要的低阶煤生产基地,但长期以来未能完全实现煤的最佳分质利用,制约着优质煤炭资源价值优势的充分发挥以及经济与社会效益的进一步提升。以此为背景,以神府南部矿区主要生产矿井低阶煤样品为研究对象,开展煤的化学组成与工艺性质测试,化学组成包括工业组分、主量元素、全硫与形态硫、有害元素P及煤灰成分等,工艺性质包括发热量、低温干馏、热稳定性与煤灰熔融性等方面。基于数量化分析方法揭示煤的化学组成与工艺性质特征及其内在关系,构建基于化学组成的工艺性质预测数学模型,为煤炭分级分质利用提供基础依据。结果显示:①研究区低阶煤资源以特低灰、特低硫、特低磷、高-特高发热量、富油、高热稳定性、弱-无黏结性为特点,品质优良,具有显著的分质利用优势,尤其广泛分布的富油煤应予以高度重视;②煤的工艺性质与化学组成之间存在密切成因联系,发热量与固定碳含量呈正相关,低温干馏焦油产率与挥发分产率、氢元素含量呈正相关,水分含量决定低温干馏总水分产率,且在特定煤类条件下,灰分产率是控制煤诸多工艺性质的关键因素,包括发热量、黏结性、焦油产率等,均呈负相关性;③基于逐步回归分析与显著性检验,建立了基于化学组成预测煤关键工艺性质的数学模型,并以张家峁矿为例,利用所建模型预测低温干馏焦油产率和富油煤分布,预测结果与实测数据相符,验证了模型的可靠性。建立的预测模型为利用早期地质勘查资料评价煤的关键工艺性质,尤其富油煤分布提供了可行途径。研究成果对丰富陆相盆地低阶煤物质组成与化学性质基础认识,刻画其内在关联属性与量化模型具有重要参考价值,可为神府南部矿区以及其他类似地区优质煤炭资源(富油煤)的科学评价与最佳利用提供参考依据。

     

    Abstract: Coal grading utilization is an essential way to fit its high-efficiency, clean and green development trends. Understanding the basic chemical composition and key technological properties of coal is the basis for achieving grading and qualitative utilization of coal resources. The South Shenfu mining area in Shaanxi Province is rich in coal reserves and it is an important low-rank coal production base in West China. However, it has not been able to achieve the qualitative utilization of coal practically completely for a long time, which restricts the full play of the value of coal resources and the further improvement of coal economic and social benefits. Based on this background, the low-rank coal samples were collected from the South Shenfu mining area to carry out coal chemical composition and technological property tests. The chemical composition tests include industrial components, major elements, total sulfur and form sulfur, harmful element P and coal ash composition. Technological property tests include calorific value, low-temperature carbonization, thermal stability and coal ash melting temperature. Quantitative analysis method was used to reveal the chemical compositions and technological properties of coal and their internal relationships. A mathematical model for predicting technological properties based on chemical compositions is constructed to provide a foundation for the grading and qualitative utilization of coal. The results show that:1) The low-rank coal resources in the study area are characterized by ultra-low ash, ultra-low sulfur, ultra-low phosphorus, high-very high calorific value, oil-rich, high thermal stability, and weak-non-adhesion characteristics, presenting a significant advantages in grading and qualitative utilization, especially the widely distributed oil-rich coal should be highly valued; 2) There is a close genetic relationship between the technological properties and chemical compositions of coal. The calorific value is positively correlated with the fixed carbon content, and the low-temperature carbonization tar yield is positively correlated with the volatile yield and hydrogen content. The moisture content determines the total moisture yield of low-temperature carbonization, and under specific coal type conditions, ash yield is a key factor controlling many technological properties of coal, including calorific value, cohesiveness, tar yield, etc., all presenting negative correlations; 3) Based on stepwise regression analysis and saliency test, a series of mathematical models for predicting the key technological properties of coal based on chemical compositions were built. Taking Zhangjiamao Mine as an example, the model was used to predict the tar yield of low-temperature carbonization and the distribution of oil-rich coal. The prediction results were consistent with the actual situation, verifying the reliability of the model. The mathematical models permit the further investigation on the coal technological properties and oil-rich coal distribution based on the geological data obtained during the previous coal exploration period. The research results have enriched the basic understanding of the material compositions and chemical properties of low-rank coals in terretrial basin, and described their intrinsic relationship and quantitative models, which can provide a theoretical foundation for the scientific evaluation and optimal utilization of high-quality coal resources(oil-rich coal) in the south Shenfu mining area and other similar areas.

     

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