表面活性剂润湿低阶煤煤尘的性能及作用机理

Wetting ability of surfactants on low-rank coal and wetting mechanism

为筛选出经济高效的低阶煤用添加剂以提高喷雾抑尘法的除尘效率,选取8种常用且经济的表面活性剂,以表面张力及煤尘沉降时间为润湿性评价指标,研究表面活性剂种类、性质及浓度对润湿低阶煤煤尘作用的影响,筛选出适合低阶煤用的添加剂,并对润湿煤尘的作用机理进行分析。结果表明实验用煤尘的可吸入尘含量较高,不易被水润湿,需添加表面活性剂提高除尘效率。8种表面活性剂均可降低溶液表面张力,增加煤尘润湿性,其临界胶束浓度和对应的表面张力值分别在0.04~0.53 g/L和25.61~34.79 mN/m之间差异较大。8种表面活性剂润湿煤尘的能力与其降低表面张力能力排序基本一致,由强到弱为APG>AOT>JFC>SDBS>OA-12>BS-12>1631>CTAB,非离子>阴离子>两性型>阳离子。0.02 g/L的APG溶液表面张力为25.87 mN/m,煤尘润湿时间为0.57 min,是一种高效经济的喷雾抑尘法添加剂。煤尘与APG吸附后表面亲水官能团数量的增加和分子间氢键的形成是APG润湿煤尘作用强的主要原因。

To screen water-spray additive for low-rank coal dust,bituminous coal dust from Yushenfu coal mining area was used as coal sample,8 cheap and representative surfactants of different categories were selected by examining the influence on surface tension and coal dust wettability by the property and concentration of surfactants.The mechanism of coal dust wettability improvement by screened surfactant was also explored.The results show that the mass of respirable dust in experimental coal dust was high and risky to miners’health,the content of ash,water was low,the content of volatile was high,and it was necessary to add surfactants to wet coal dust.The surface tension was reduced and the coal dust wettability was increased by all experimental surfactants.The critical micelle concentration and surface tension was in the range of 0.04~0.53 g/L and 25.61~34.79 mN/m.The wetting ability of surfactants was ranked as follows:APG>AOT>JFC>SDBS>OA-12>BS-12>1631>CTAB,consistent with the surface tension reduction ability ranking.The non-ionic surfactant APG demonstrated the best surface activity;the surface tension and coal dust wetting time of 0.02 g/L APG solution was 25.87 mN/m and 0.57 min,respectively.0.02 g/L APG solution is an effective and cheap water-spray additive for low-rank coal dust.The increase of hydrophilic group on coal dust and the formation of hydron bond are the main reasons of APG to wet coal dust.