高泥化煤泥水中微细颗粒疏水聚团特性及机理研究

发布时间：2018-06-25 14:39

  本文选题：高泥化煤泥水 + 疏水聚团沉降　； 参考：《安徽理工大学》2017年博士论文

【摘要】：煤泥水是一种选煤厂湿法洗煤产生的工业废水,它的沉降澄清是选煤工艺流程中的关键环节之一。然而,由于采煤机械化程度加大及原煤煤质变差,导致大量高泥化煤泥水的产生,高泥化煤泥水具有粒度细、粘土矿物含量高及颗粒表面电负性强等特点,严重加大了煤泥水处理的难度。本文以淮南矿区高泥化煤泥水及煤泥水中主要微细颗粒煤和高岭石为研究对象,采用试验和量子化学/分子动力学模拟相结合的方法,对疏水改性剂作用下高泥化煤泥水中微细颗粒疏水聚团特性及机理进行了深入研究,为高泥化煤泥水沉降澄清的新技术开发及新药剂设计提供理论基础。煤泥水中微细颗粒疏水聚团特性研究表明,阳离子胺/按盐类疏水改性剂能够通过静电引力作用自发吸附在荷负电的微细煤泥矿物颗粒表面,改善颗粒表面疏水性,降低颗粒表面电负性,促进颗粒在疏水引力作用下形成疏水聚团,进而促进微细煤泥矿物颗粒的疏水聚团沉降。疏水改性剂作用下单一煤聚团沉降效果弱于单一高岭石的聚团沉降效果。药剂种类及药剂用量、动能输入、矿浆浓度和矿浆pH是影响微细煤泥矿物颗粒疏水聚团沉降效果的主要影响因素。药剂种类和药剂用量主要通过控制微细颗粒形成疏水聚团的尺寸大小,影响其疏水聚团沉降效果;合适的动能输入和矿浆浓度有利于微细煤泥矿物颗粒的疏水聚团沉降;微细煤泥矿物颗粒疏水聚团沉降的最佳矿浆pH为弱碱性。D和L煤泥水的最佳疏水聚团沉降条件为:1831用量3000g/t、搅拌强度750r/min及搅拌时间10min,该条件下两煤泥水的沉降速度和透光率分别可达0.83 cm/min、78.6%及1.31 cm/min、62.4%。同时,混凝剂与疏水改性剂复配使用,不仅能减少各药剂的用量,还能显著提高高泥化煤泥水的疏水聚团沉降效果。混凝剂与1831的最佳复配用量为:絮凝剂APAM 40 g/t、凝聚剂CaCl_2 10000 g/t时及1831 1500 g/t,此条件下煤泥水的初始沉降速度达0.97 cm/min,透光率达84.1%。煤表面吸附的DFT模拟研究表明,水分子主要通过与煤表面不同含氧官能团形成氢键吸附到煤表面,且在不同煤含氧结构表面吸附的稳定性大小为-COOH-C=OPh-OH-O-;不同甲基胺/铵阳离子主要通过与煤表面不同含氧官能团形成N-H...O或C-H...O氢键吸附到煤表面,且在不同煤含氧结构表面吸附的稳定性大小为-C=O-COOH-O-Ph-OH;水及不同甲基胺/铵阳离子在煤含氧结构表面吸附的稳定性大小为:H_2OCH_6N~+_C2H_8N~+C_3H_(10)N~+C_4H_(12)N~+,即水溶液环境中甲基胺/铵阳离子在煤含氧结构表面的吸附状态不稳定。高岭石表面吸附的DFT研究表明,水分子主要通过氢键吸附在高岭石(001)面和(001)面,单个水分子在高岭石(001)面不同位置的吸附能为-72.12～-19.23 kJ/moL小于其在高岭石(001)面不同位置的吸附能-19.23～-5.77 kJ/moL,即水分子更容易吸附在高岭石(001)面;不同甲基胺/铵阳离子主要通过静电作用和氢键吸附在高岭石(001)面和(001)面,且更容易吸附在高岭石(001)面;不同甲基胺/铵阳离子在高岭石(001)面最佳吸附位为H3位,吸附能(按伯胺阳离子、仲胺阳离子、叔胺阳离子及季铵阳离子顺序,下同)分别为-125.385、-126.154、-128.654 及-109.711 kJ/mol,在高岭石(001)面最佳吸附位都为 H1位,吸附能分别为-140.961、-136.154、-138.558 及-115.961 kJ/mol;不同十二烷基胺/铵阳离子在高岭石(001)面不同穴位吸附稳定性为H3H2H1,在高岭石(001)面不同穴位吸附稳定性为H1H2H3;不同碳链长度的季铵阳离子在高岭石(001)面及(001)面吸附稳定性随着季铵盐碳链长度的增加而减小。不同煤含氧结构单元主要通过形成氢键及苯环与表面间的作用吸附在高岭石(001)面和(001)面,且吸附平衡后煤含氧结构中的苯环近似平行于高岭石(001)面和(001)面;不同煤含氧结构单元在高岭石在高岭石(001)面及(001)面吸附稳定性大小分别为-COOHPh-OH-C=O-O-和-COOH-C=O-O-Ph-OH,且煤含氧结构更容易吸附在高岭石(001)面。烟煤表面吸附的MD模拟研究表明,随着水层水分子数从200增加至1600,烟煤表面对水分子的界面效应逐渐减小,水分子逐渐远离表面,且水分子间排列的有序度不断减小。十二烷基伯胺阳离子和十八烷基三甲基氯化铵阳离子在烟煤/水界面处吸附平衡后,其碳链都发生严重扭转现象,且大部分阳离子极性头基朝向溶液,对烟煤表面疏水改性效果不理想。高岭石表面吸附的MD模拟研究表明,随着水覆盖率从2/3 ML不断增大到8/3 ML,高岭石表面对水分子的束缚力逐渐减小,界面处的氢键作用逐渐减弱,且水分子逐渐形成多个水分子层;相同水覆盖率时,高岭石(001)面对水分子的界面效应弱于高岭石(001)面对水分子的界面效应。十二烷基伯胺阳离子和十八烷基三甲基氯化铵阳离子在高岭石/水界面处吸附平衡后,阳离子主要以极性头基吸附在高岭石表面,非极性碳链朝向溶液,并发生一定程度扭转,不同阳离子碳链通过疏水缔合作用吸引到一起使表面疏水化。烟煤大分子在高岭石(001)面及(001)面动力学平衡后,烟煤分子中部分苯环结构近似平行与高岭石表面,这一结果进一步说明,煤与高岭石颗粒间的相互作用,除了煤分子中含氧官能团与高岭石表面的氢键作用外,煤分子中活性较强的苯环与高岭石表面也存在较强的作用,即微细煤与高岭石间的相互作用机制主要是氢键作用和煤结构中苯环与高岭石表面间作用的综合作用。阳离子胺/铵盐类疏水改性剂对煤泥颗粒的疏水聚团作用机理主要是"吸附电中和"和疏水引力综合作用的结果。阳离子胺/铵盐类疏水改性剂作用下高泥化煤泥水中微细粒矿物疏水聚团沉降的作用机理,主要是疏水改性剂阳离子通过静电引力和氢键作用吸附在微细煤泥矿物颗粒表面,对颗粒表面进行疏水改性:一方面弱化煤泥颗粒间水化斥力,提高煤泥颗粒间疏水引力;另一方面,降低煤泥矿物颗粒表面电负性,压缩颗粒表面双电层,降低颗粒间静电斥力,进而实现煤泥颗粒的疏水聚团沉降。
[Abstract]:Coal mud water is a kind of industrial waste water produced by wet coal washing in coal preparation plant. Its settlement clarification is one of the key links in the process of coal preparation. However, due to the increasing mechanization of coal mining and the poor quality of the raw coal and coal, a large number of highly muddy coal mud water is produced. The high muddy coal mud has fine grain size, high clay mineral content and particle surface. In this paper, the high muddy coal mud water and the main fine particle coal and kaolinite in the coal mud water in Huainan mining area are studied in this paper. The hydrophobicity of fine particles in high mud slime water under the action of hydrophobic modifier is used by the method of combining the experiment with the quantum chemistry / molecular dynamics simulation. The characteristics and mechanism of agglomeration are studied in depth, which provide a theoretical basis for the new technology development and new drug design for high mud water settlement clarification. The study of the hydrophobic agglomeration characteristics of the fine particles in the slime water shows that the cationic amines / salt hydrophobic modifiers can be adsorbed spontaneously in the micro slime minerals in the negative electricity by electrostatic force. The surface of the particle can improve the hydrophobicity of the surface of the particles, reduce the electronegativity on the surface of the particles, promote the formation of hydrophobic agglomeration of particles under the action of hydrophobic gravitation, and then promote the hydrophobic agglomeration settlement of the fine slime mineral particles. The effect of the settlement of single coal agglomeration under the action of hydrophobic modifier is weaker than the aggregation settlement effect of single kaolinite. The amount, kinetic energy input, pulp concentration and pulp pH are the main factors affecting the hydrophobic agglomeration effect of the fine slime mineral particles. The kinds of agents and the dosage of the medicament mainly form the size of the hydrophobic agglomeration by controlling the fine particles, and affect the effect of the hydrophobic agglomeration settlement, and the appropriate kinetic energy input and pulp concentration are beneficial to the fine particles. The best slurry pH for the hydrophobic agglomeration of the fine slime mineral particles is the best hydrophobic agglomeration condition of the weak alkaline.D and L coal mud water, which is 1831 3000g/t, the stirring strength 750r/min and the stirring time 10min, and the sedimentation rate and transmittance of the two coal mud water can reach 0.83 cm/min, 78 respectively under this condition. .6% and 1.31 cm/min, 62.4%. simultaneously, the mixture of coagulant and hydrophobic modifier can not only reduce the dosage of various agents, but also significantly improve the hydrophobic agglomeration effect of high mud coal mud water. The optimum compound dosage of coagulant and 1831 is flocculant APAM 40 g/t, coagulant CaCl_2 10000 g/t and 18311500 g/t, under this condition coal mud water The initial sedimentation rate is 0.97 cm/min. The DFT simulation study on the adsorption of 84.1%. on coal surface shows that water molecules mainly form hydrogen bonds with different oxygen containing functional groups on the coal surface to adsorb to the coal surface, and the stability of the adsorption on the surface of different coal containing oxygen structure is -COOH-C= OPh-OH-O-, and the different methyl amine / ammonium cation is mainly passed through. The hydrogen bonds of N-H... O or C-H... O are adsorbed on coal surface with different oxygen functional groups on coal surface, and the stability of adsorption on the surface of different coal containing oxygen is -C=O-COOH-O-Ph-OH. The stability of water and different methyl amine / ammonium cation adsorption on the surface of coal containing oxygen is H_2OCH_6N~+_C2H_8N~+C_3H_ (10) N~+C_4H_ (12) N~+, that is water solubility. The adsorption state of methyl amine / ammonium cation on the surface of coal containing oxygen is unstable in liquid environment. DFT study on the adsorption of kaolinite surface shows that water molecules are adsorbed mainly on kaolinite (001) and (001) surfaces through hydrogen bonds, and the adsorption energy of single water molecules at different positions of kaolinite (001) is -72.12 to -19.23 kJ/moL less than that of kaolinite (001) The adsorption energy of different positions can be -19.23 ~ -5.77 kJ/moL, that is, water molecules are more easily adsorbed on kaolinite (001). Different methylamine / ammonium ions are adsorbed on kaolinite (001) and (001) surface mainly by electrostatic and hydrogen bonds, and are more easily adsorbed on kaolinite (001). The best adsorption sites of different methyl amine / ammonium cation on kaolinite (001) surface For H3 position, the adsorption energy (according to the order of primary amine cation, secondary amine cation, tertiary amine cation and quaternary ammonium cation, the same below) is -125.385, -126.154, -128.654 and -109.711 kJ/mol respectively. The best adsorption sites for kaolinite (001) are H1 sites, and the adsorption energy is -140.961, -136.154, -138.558 and -115.961 kJ/mol, and different twelve alkyl amines / ammonium positive. The adsorption stability of different acupoints on kaolinite (001) surface is H3H2H1, and the adsorption stability is H1H2H3 at different acupoints on kaolinite (001). The adsorption stability of quaternary ammonium cation on kaolinite (001) surface and (001) surface decreases with the increase of the length of quaternary ammonium salt carbon chain. The interaction between the benzene ring and the surface is adsorbed on the kaolinite (001) and (001) surfaces, and the benzene ring in the oxygen containing structure is approximately parallel to the kaolinite (001) and (001) surfaces after the adsorption equilibrium. The adsorption stability of different coal containing oxygen structural units in kaolinite (001) and (001) surfaces is -COOHPh-OH-C=O-O- and -COOH-C=O-O-Ph-OH, respectively. The oxygen containing structure is more easily adsorbed on the kaolinite (001) surface. The MD simulation study on the surface adsorption of bituminous coal shows that the interfacial effect of water molecules on the surface of the bituminous coal gradually decreases with the number of water molecules from 200 to 1600, and the water molecules are gradually far away from the surface, and the order of the arrangement of water molecules decreases continuously. Twelve alkyl amine amines and eighteen alkanes. After adsorption equilibrium at the bituminous coal / water interface, the carbon chain of the base three methyl ammonium chloride is seriously torsional, and most of the cationic polar heads are directed towards the solution, and the hydrophobic modification effect on the surface of the bituminous coal is not ideal. The MD simulation study on the adsorption of kaolinite surface shows that with the increasing water coverage from 2/3 ML to 8/3 ML, kaolinite The binding force of the surface to water molecules gradually diminished, the hydrogen bond at the interface weakened gradually, and the water molecules gradually formed a number of water molecular layers, and the interface effect of kaolinite (001) facing water molecules was weaker than the interface effect of kaolinite (001) on water molecules. Twelve alkyl primary amine cations and eighteen alkyl three methyl chlorination were found in the same water coverage. After the adsorption equilibrium of ammonium cation at the kaolinite / water interface, the cation mainly adsorbs on the surface of Kaolinite on the polar head base, the non polar carbon chain faces the solution, and turns to a certain extent. The different cation carbon chains are attracted by the hydrophobicity association to make the surface hydrophobicity together. The kinetics of the kaolinite (001) surface and (001) surface dynamics of the coal large molecule After the balance, some of the benzene ring structure in the bituminous coal is approximately parallel to the kaolinite surface. This result further indicates that the interaction between coal and kaolinite particles, besides the hydrogen bond between the oxygen containing functional group and the kaolinite surface in the coal molecules, has a strong effect on the surface of the coal and kaolinite, that is, the surface of the kaolinite. The interaction mechanism between coal and kaolinite is mainly the interaction of hydrogen bond and the interaction between the benzene ring and the kaolinite surface in the coal structure. The mechanism of the hydrophobic polymerization of the cationic amine / ammonium salt hydrophobic modifier to the slime particles is mainly the result of the synthesis of "adsorption electricity neutralization" and the hydrophobic attraction. The hydrophobic modification of cationic amine / ammonium salt type is the result. The mechanism of hydrophobic aggregation settlement of fine particles in slime water under the action of sex agent is mainly that hydrophobic modifier cations are adsorbed on the surface of fine slime mineral particles through electrostatic and hydrogen bonds, and the surface of the particles is modified by hydrophobicity. On the one hand, it weakens the hydration repulsion between the slime particles and improves the hydrophobic attraction between the slime particles. On the other hand, it reduces the surface electronegativity of the slime mineral particles, compresses the double layer of particles on the surface of the particles, reduces the electrostatic repulsion among the particles, and then realizes the hydrophobic agglomeration settlement of the slime particles.
【学位授予单位】：安徽理工大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：X752
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本文编号：2066350