烃类捕收剂性能的量子化学计算与试验研究

发布时间：2018-06-10 02:38

本文选题：烃 + 捕收剂　；参考：《太原理工大学》2015年硕士论文

【摘要】：煤炭洗选是洁净煤技术的基础，就细粒煤分选而言，浮选是最有效的分选方法。浮选效果与浮选药剂的选择和使用有很大关系，高效合理的浮选药剂能灵活地控制浮选过程，提高经济效益。浮选药剂分子结构与性能关系的研究，是开发高效新药剂的前提。量子化学计算方法为研究浮选机理和设计新型浮选剂提供了一个良好的平台。论文采用量子化学计算Gaussian软件建立了不同结构的烃类捕收剂(烷烃、烯烃、芳烃)的结构模型，采用密度泛函理论（DFT），在B3LYP/6-311G水平上对三类捕收剂的几何构型、净电荷、前线分子轨道构成等电子结构参数，以及烃类捕收剂与煤的吸附能等进行了计算，从量子化学角度揭示了煤与药剂的作用机理，并通过润湿热的测量和单元浮选试验对计算结果进行验证。以大同煤为研究对象，通过工业分析、红外光谱分析、XPS分析等研究了煤样性质，结果表明：煤样为变质程度较低的弱粘煤，表面O元素的含量较高，主要以-OH的形式存在。基于煤样性质，选取次烟煤的结构单元模型进行量子化学计算。选取碳原子数为12、14、16的烷烃、烯烃和芳烃类捕收剂为研究对象，采用量子化学计算Gaussian软件建立其结构模型，计算了它们的几何构型、净电荷、前沿分子轨道构成等电子结构参数。结果表明：同系列烃类捕收剂，，碳链长度对其性能的影响不明显。不同结构烃类捕收剂，电荷分布、键长、键角等有一定的差距，导致其性质有所不同；前线轨道能隙ΔELUMO－HOMO按烷烃、烯烃和芳烃依次减小，可以初步判断其反应活性为：烷烃＜烯烃＜芳烃。采用量子化学计算Material Studio软件计算了煤与几种烃类捕收剂相互作用的吸附能。结果表明：烃类捕收剂与煤作用的吸附能均小于84kJ/mol，因此烃类捕收剂在次烟煤表面的吸附过程为物理吸附。吸附能越大，药剂与煤表面的作用越强，不同结构烃类捕收剂吸附能大小依次为：芳烃＞烯烃＞烷烃。吸附过程中产生的吸附热反映了捕收剂与矿物作用的强弱，采用C80微量热仪测定了不同捕收剂与煤作用的润湿热，结果表明煤与烃类捕收剂润湿热的大小依次为：芳烃＞烯烃＞烷烃。通过不同捕收剂用量的单元浮选试验，得到了精煤产率、精煤灰分、可燃体回收率、浮选完善度等浮选指标。结果表明：在药剂用量相同条件下，精煤产率、可燃体回收率、浮选完善的大小依次为：芳烃＞烯烃＞烷烃。 C80微量热仪对捕收剂与煤作用的润湿热测定以及煤泥浮选试验结果均表明：碳原子数相同的不同结构烃类捕收剂的捕收性能为芳烃＞烯烃＞烷烃，但是同系列药剂中，碳原子数增加，药剂粘度增大，在矿浆中分散度降低，浮选效果变差，受药剂粘度的影响，同系列捕收剂浮选试验中，药剂性质随碳原子数呈相反规律。量子化学计算与试验相结合的研究方法，为煤泥浮选药剂的研究与开发提供了新的技术途径。
[Abstract]:Coal washing is the basis of clean coal technology. Flotation is the most effective separation method for fine coal separation. The effect of flotation is closely related to the selection and use of flotation reagents. High efficiency and reasonable flotation reagents can control the flotation process flexibly and improve the economic benefit. The study of the relationship between the molecular structure and performance of the flotation agent is a high development. The quantum chemical calculation method provides a good platform for studying the flotation mechanism and designing new flotation agents.
The structure model of hydrocarbon collector (alkane, alkene, aromatics) of different structures was established by quantum chemical calculation Gaussian software. The geometric configuration of three collectors, net charge, the composition of frontline molecular rail, and the absorption of hydrocarbon collector and coal were established by the density functional theory (DFT). The effect mechanism of coal and drug is revealed from the angle of quantum chemistry, and the results are verified by the measurement of wet heat and the unit flotation test.
Taking Datong coal as the research object, the properties of coal samples are studied by industrial analysis, infrared spectrum analysis and XPS analysis. The results show that the coal samples are weak coal with low metamorphic degree, the content of O elements on the surface is higher, mainly in the form of -OH. Based on the properties of coal samples, the structure unit model of secondary bituminous coal is selected for quantum chemical calculation.
The alkane, olefins and aromatics collector are selected as the research object of 12,14,16. The structural models of their geometric configuration, net charge and frontier molecular orbit are calculated by the quantum chemical calculation Gaussian software. The results show that the same series of hydrocarbon collectors and the carbon chain length have a shadow on their properties. The properties of hydrocarbon collector in different structure, charge distribution, bond length and bond angle are different, and the front orbital energy gap Delta ELUMO HOMO decreases in order of alkanes, olefins and aromatics, which can be preliminarily judged as alkanes < olefins < aromatics.
The adsorption energy of coal and several hydrocarbon collectors was calculated by quantum chemical calculation Material Studio software. The results show that the adsorption energy of hydrocarbon collector and coal is less than 84kJ/mol, so the adsorption process of hydrocarbon collector on the surface of sub bituminous coal is physical adsorption. The greater the adsorption energy, the stronger the effect of the agent and the surface of coal. The adsorption energy of hydrocarbon collector with different structures is: aromatics > olefins > alkanes.
The adsorption heat produced during the adsorption process reflects the strength of the collectors and minerals. The wet heat of different collectors and coal is measured by C80 microcalorimeter. The results show that the size of wet heat of coal and hydrocarbon collectors is aromatics > alkenes > alkanes.
Through the unit flotation test of different collector dosage, the flotation indexes such as the yield of refined coal, the ash of the coal, the recovery of the combustibles and the perfection of the flotation have been obtained. The results show that, under the same dosage, the yield of the coal, the recovery rate of the flammable body, and the perfect size of the floatation are aromatics > alkenes > alkanes.
The results of wet heat determination of collectors and coal by C80 microcalorimeter and the test results of coal slime flotation show that the collecting properties of different hydrocarbon collectors with the same number of carbon atoms are aromatics > alkenes > alkanes, but in the same series of chemicals, the number of carbon atoms increases, the viscosity of the reagent increases, the dispersion degree decreases in the pulp and the flotation effect becomes worse. In the flotation test of series collector, the nature of the reagent is contrary to the number of carbon atoms.
The combination of quantum chemistry calculation and experiment provides a new technical way for the research and development of coal flotation reagents.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD923.13;TD94

【参考文献】