非离子型分散剂对低阶煤制备水煤浆的影响

为了改善低阶煤制水煤浆品质差的现状,实现低阶煤的高效清洁利用,采用非离子型表面活性剂壬基酚聚氧乙烯醚(NPEO-40)作为分散剂制备低阶煤水煤浆,并进行水煤浆成浆性能及成浆机理研究。神东煤(SDC)低阶煤水煤浆试验表明,水煤浆表观黏度η100随NPEO-40用量的增加而降低,当NPEO-40用量增加到1.0%,η100基本保持不变。添加剂用量为1%、水煤浆浓度为60%~68%时,浆体呈剪切变稀的假塑性流体,最大成浆浓度C1000=67.5%;水煤浆浓度为60%~68%时,浆体稳定性随浓度的升高而降低。等温吸附研究表明,NPEO-40在低阶煤表面的吸附行为符合Langmuir等温吸附模型,且吉布斯自由能ΔGa0ds=-29.27 kJ/mol,说明反应自发进行。浸润试验表明,1.0%的NPEO-40适于SDC在溶液中的浸润。对吸附前后的煤进行XPS C1s窄程扫描,C—C/C—H官能团含量由78.79%下降到70.12%。含氧官能团C—O,C■O和O■C—O总含量由21.21%增加至29.88%,说明吸附NPEO-40后,其疏水官能团与煤表面的C—C/C—H官能团结合,使含氧官能团暴露在外侧,从而使煤表面C—C/C—H官能团含量减少,含氧官能团比例增大,亲水性增强,利于形成水化膜,通过水化膜将煤粉颗粒彼此分开,进而减少了煤粉颗粒间的流动阻力,从而对水煤浆起到降黏效果。

Effect of non-ionic dispersant on the preparation of CWS from low rank coal

In order to improve the poor quality of coal water slurry from low rank coal and realize the efficient and clean utilization of low rank coal,nonylphenol polyoxyethylene ether( NPEO-40),a non-ionic surfactant,was used as dispersant to prepare low rank coal water slurry. The research on the slurrying performance and the mechanism of coal water slurry was carried out. The test of Shendong coal( SDC)low-rank coal water slurry shows that the apparent viscosity η100 of coal water slurry decreases with the increase of NPEO-40 dosage.When the dosage of NPEO-40 increases to 1.0%,the apparent viscosity η100 remains basically constant. When the dosage of additive is1% and the concentration of coal water slurry is 60%-68%,the slurry is a pseudoplastic fluid with shear thinning,and the maximum slurry concentration C1000 is 67.5%. When the concentration range of low rank coal water slurry is 60%-68%,the stability of slurry decreases with the increase of concentration. Isothermal adsorption studies show that the adsorption behavior of NPEO-40 on low rank coal surface is in accordance with Langmuir isothermal adsorption model and Gibbs free energy ΔGa0 dsis-29.27 k J/mol,proving that the reaction occurs spontaneously. The infiltrating experiment shows that when the dosage of NPEO-40 is 1.0%,it will be beneficial to the coal infiltration in the solution. XPS narrow-range scanning is performed on the coal before and after adsorption,and the content of C-C/C-H functional group decreases from 78.79% to 70.12%. The total amount of oxygen-containing functional groups C-O,C■O,and O■C-O increases from 21.21% to 29.88%,indicating that the hydrophobic functional group of NPEO-40 is combined with the C-C/C-H functional group on the coal surface after adsorption of NPEO-40. Therefore,the oxygen-containing functional group is exposed to the outside,thereby reducing the content of C-C/C-H functional group on the coal surface. The proportion of oxygen-containing functional groups increases and the hydrophilicity is enhanced,which is conducive to the formation of a hydration film. The pulverized coal particles are separated from each other through the hydration film,thereby reducing the flow resistance between the pulverized coal particles and achieving a viscosity reduction effect.