本文選題：煤泥　切入點：脫水特性　出處：《太原理工大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著選煤技術(shù)的發(fā)展,在大多數(shù)選煤廠中,濕法選煤占據(jù)主要地位,由此帶來的問題便是最終煤炭產(chǎn)品中的水分需要脫除。煤泥脫水往往伴隨著濾餅的生成,而濾餅結(jié)構(gòu)在很大程度上影響著脫水效果,一方面,濾餅結(jié)構(gòu)受煤泥特性、煤漿性質(zhì)的影響,另一方面,藥劑制度也與濾餅結(jié)構(gòu)有著密切的聯(lián)系。本文主要研究了煤泥在不同條件下的脫水試驗,分析了各種條件下的濾餅結(jié)構(gòu)特性及其對脫水效果的影響機理,同時探索了煤泥脫水過程中,濾餅的動態(tài)生長規(guī)律,并利用灰色關(guān)聯(lián)法分析了各因素對濾餅水分的影響程度,結(jié)果表明:(1)煤的變質(zhì)程度對煤泥的脫水效果影響顯著,中等變質(zhì)程度的煤樣脫水效果最好,變質(zhì)程度過高或過低,都將不利于脫水的進行。煤泥粒度越大,所形成的濾餅比阻越小,孔隙率越大,水分在濾餅中的流動更加通暢,脫水速度越大,同時濾餅的分形維數(shù)隨著煤泥粒度的增大而減小,孔隙內(nèi)表面積減小,水分更易排出,使得最終的濾餅水分降低。由于黏土礦物在1.4-1.6g/cm~3密度級的煤泥中的富集使得濾餅比阻增大,孔隙率降低,脫水效果變差。(2)隨著煤漿濃度的增加,濾餅的孔隙率降低,不利于的脫水的進行,同時分形維數(shù)變大,孔隙內(nèi)表面更加粗糙,使得水分的排出難度加大。p H越小,煤漿中的H~+離子濃度越大,降低了顆粒表面對水分子的吸引力,使得二者更容易分離,同時隨著pH的減小,濾餅的上表面的孔隙率增大,分形維數(shù)有所減小,濾餅比阻降低,更有利于脫水。(3)隨著脫水過程的進行,濾餅孔隙的分形維數(shù)有所增加,濾餅的孔隙率先稍有增大后減小,在表面水消失之后繼續(xù)進行脫水,又可以使得孔隙率有所增大。其中濾餅上表面的孔隙率隨脫水時間變化的數(shù)學(xué)模型為:y=0.673x~2 9.982x+40.37,濾餅縱剖面的孔隙率隨脫水時間變化的數(shù)學(xué)模型為:y=0.291x~2 4.223x+45.15。(4)通過比較各種價態(tài)及陰陽離子對煤泥脫水效果的影響可知,在陰離子為Cl~-時,一價陽離子K+和Na~+可以有效降低濾餅水分;二價陽離子Mg~(2+)和Ca~(2+)降低濾餅水分、提高脫水速度的效果更明顯,其中Ca~(2+)的效果優(yōu)于Mg~(2+);三價陽離子Fe~(3+)和Al~(3+)的助濾效果最好,Al~(3+)的穩(wěn)定性高于Fe~(3+)。陽離子為Na~+時,陰離子Cl-的脫水效果最好,SO_4~(2-)次之,NO_3~-最差。(5)通過對不同藥劑制度下的煤泥脫水效果對比分析可知,陽離子聚丙烯酰胺的助濾效果最佳,最佳藥劑用量為150g/t,脫水速度為0.09mL/s.cm~2,此時的濾餅比阻最小,濾餅上表面的孔隙率最大為31%,分形維數(shù)小,最有利于脫水的進行。(6)利用灰色關(guān)聯(lián)分析得到,各因素對濾餅水分影響程度從大到小排序依次為:顆粒粒度、煤漿濃度、煤漿pH、陽離子聚丙烯酰胺用量、煤樣變質(zhì)程度、AlCl_3用量。
[Abstract]:With the development of coal preparation technology, wet coal preparation occupies the main position in most coal preparation plants, which brings about the problem that the moisture in the final coal products needs to be removed. On the one hand, the structure of filter cake is affected by the characteristics of coal slime, coal slurry, on the other hand, The medicament system is also closely related to the structure of filter cake. In this paper, the dewatering tests of coal slime under different conditions are mainly studied, and the structural characteristics of filter cake under various conditions and its influence mechanism on the dehydration effect are analyzed. At the same time, the dynamic growth law of filter cake in the process of coal slime dehydration is explored, and the influence of various factors on moisture content of filter cake is analyzed by using grey correlation method. The results show that the degree of metamorphism of coal has a significant influence on the dehydration effect of coal slime. Coal samples with medium metamorphic degree have the best dehydration effect, too high or too low degree of metamorphism will be unfavorable to dewatering. The larger the particle size of coal slime, the smaller the specific resistance of the filter cake, the larger the porosity, and the more smooth the flow of water in the filter cake. With the increase of dehydration rate, the fractal dimension of filter cake decreases with the increase of coal particle size, the internal surface area of pore decreases, and the water is discharged more easily. Due to the enrichment of clay minerals in the coal slime of 1.4-1.6 g / cm ~ 3 density grade, the specific resistance of filter cake increases, the porosity decreases, and the dehydration effect becomes worse. 2) with the increase of coal slurry concentration, the porosity of filter cake decreases. At the same time, the fractal dimension becomes larger and the inner surface of the pore becomes rougher. The smaller the water excretion is, the smaller the H ~ + concentration in the coal slurry is, which reduces the attraction of the particle surface to the water molecules. At the same time, with the decrease of pH, the porosity of the upper surface of the filter cake increases, the fractal dimension decreases, and the specific resistance of the filter cake decreases, which is more favorable to the dehydration process. The fractal dimension of filter cake pore increased, the pore of filter cake increased slightly and then decreased, and then dehydrated after the surface water disappeared. The porosity of the upper surface of the filter cake varies with the dehydration time, and the mathematical model of the change of porosity with dehydration time of the filter cake is:: yyong 0.673xf2, 9.982x 40.37. the mathematical model of the variation of porosity with dehydration time of the filter cake profile is:: yyyong 0.291xf2 / 4.223x 45.15.4) by comparison, the porosity of the filter cake is 0.291x2 / 2 and 4.223x / 45.15.4 respectively. The effect of species valence and anion on the dewatering effect of coal slime is known. When the anion is Cln-, monovalent cations K and Na ~ can effectively reduce the moisture of filter cake, and the divalent cations Mg~(2) and Ca~(2) decrease the moisture of filter cake, and the effect of increasing dehydration rate is more obvious. The effect of Ca~(2) is better than that of Mg~(2, and that of trivalent cations Fe~(3) and Al~(3) is better than that of Fe~(3. The dehydration effect of anionic Cl- is better than that of SOS _ 4N _ 2) followed by No _ 3- worst. (5) by comparing and analyzing the dewatering effect of coal slime under different medicament systems, we can see that cationic polyacrylamide is the best filter aid. The optimum dosage is 150g / t, the dehydration rate is 0.09mL / s 路cm-2, the filter cake has the smallest specific resistance, the maximum porosity on the surface of the filter cake is 31g / t, the fractal dimension is small, and the dehydration is most favorable. The order of influencing factors on the moisture content of filter cake is: particle size, coal slurry concentration, coal slurry pH, cationic polyacrylamide content, coal sample metamorphism degree and AlCl3 consumption.
【學(xué)位授予單位】：太原理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TD94

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