不同表面活性剂对镜煤和暗煤的润湿性影响

Influence of different surfactants on wettability of vitrain and durain

为研究烷基糖苷、十六烷基三甲基氯化铵、十二烷基二甲基甜菜碱、十二烷基苯磺酸钠等4种表面活性剂对镜煤和暗煤润湿性的影响,通过煤矿井下煤层块样分离出镜煤和暗煤成分,利用接触角测定、润湿热测定、粉末浸透试验、吸水核磁共振测试等多种技术手段,分析镜煤和暗煤润湿性差异。结果表明:低阶煤具弱亲水性,与镜煤相比,暗煤的接触角更小,暗煤的润湿热和表面自由能更高,粉末浸透速率快,吸水能力强,暗煤的亲水性比镜煤强;4种不同类型的表面活性剂均可显著降低水的表面张力,而且随着活性剂溶液浓度的增加,煤样表面的接触角明显减小,不同类型表面活性剂溶液与煤样接触角的变化趋势略有不同;阳离子表面活性剂与阴离子表面活性剂随溶液浓度增加接触角呈现指数函数降低;非离子表面活性剂对接触角的作用则呈现二次函数降低,曲线变化趋势反映了影响机制的差异;表面活性剂作用下暗煤的黏附功降低因子小于镜煤,煤中水分主要为吸附态水和游离态水,以吸附态水为主。镜煤中吸附态水比例高,游离态水比例低。4种表面活性剂均增强了煤的吸水能力。

In order to study the effects of four surfactants,APG0810,CTAC,BS-12 and SDBS on the vitrain and durain,the compositions of itrain and durain were separated,by collecting coal seam samples from underground coal mine,and the wettability difference between vitrain and durain was analyzed by using different techniques of contact angle measurement,wetting heat measurement,powder penetration test,water absorption nuclear magnetic resonance test.The results show that low-rank coal is weak in hydrophilicity;compared with vitrain,durain is smaller in contact angle,higher in wetting heat and in surface free energy,faster in powder penetration rate and stronger in water absorption capacity,so its hydrophilicity is stronger than that of vitrain.The four different types of surfactants can significantly reduce the surface tension of water,and with the increase of the concentration of the surfactant solution,the contact angle on the coal sample surface decreases significantly,and the change trend of the contact angle between the different types of surfactant solution and the coal sample is slightly different.The contact angle between cationic and anionic surfactants decreases exponentially with solution concentration increased.The effect of nonionic surfactants on antennae decreases as a quadratic function,and the variation trend of the curve reflectes the difference of the influencing mechanism.The adhesion reduction factor of durain under the action of surfactant is smaller than that of vitrain.The water in coal is mainly adsorbed water and free water,mainly adsorbed water.Compared with durain,vitrain has a higher proportion of adsorbed water and a lower proportion of free water.All the four surfactants enhance the water absorption capacity of coal.