寒冷地区不同煤样冻黏强度试验研究

Experimental study for the frozen adhesive strength of the different coal samples in the severe cold atmospheric regions

寒冷地区煤炭运输设备上煤的冻黏严重影响煤炭运输的安全与效率,为分析各地不同煤样的冻黏强度特性及原因,选取各地5个存在冻黏现象煤矿的煤样,测试其在Q235和UHMWPE材料上的冻黏强度,并检测5种煤样的外在水质量分数、粒度和孔容分布,结果表明：在亲水性Q235材料上,内蒙古锡林浩特煤样冻黏强度最高（2.58 MPa）,其次是辽宁铁法煤样（2.02 MPa）和黑龙江双鸭山煤样（1.36 MPa）,北京大安山（0.773 MPa）和木城涧煤样（0.689 MPa）较低;不同煤样在疏水性UHMWPE材料上的冻黏强度分布在0.159-0.230 MPa。各煤样因煤质、采掘破碎工况、煤化程度等因素导致其粒度和孔容分布不同,使各自外在水质量分数不同,进而导致煤样在亲水性Q235材料上冻黏强度差别明显,外在水质量分数高的煤样冻黏强度相对较高;在UHMWPE材料上,各煤样的冻黏强度因材料的疏水性而对外在水质量分数差异不敏感,因而普遍很低且差别很小,可见采用UHMWPE基体材料对各地煤在运输设备上的冻黏具有一定防治作用。

This paper takes it as its target to analyze the characteristic features and rationales of the frozen adhesive strength of the different coal samples taken from the different low-temperature regions. For this purpose,we have chosen five coal samples from the different coal mines to test their frozen adhesive strength on a steel plate and UHMWPE material plate,along with the examination and testing of some other items,such as the free moisture content,the granularity and the pore volume distribution of the said samples. As a result,it has been found that,for the hydrophilic steel material,the coal samples from Xilin-hot Mine of the Inner Mongolian Autonomous Region enjoy the greatest frozen adhesive strength of all the samples from all the coal-mines chosen,that is,2. 58 MPa. And,the samples from Tie-fa Mine in Liaoning and Shuangyashan Mine in Heilong Jiang tend to follow,whose adhesive strengths account for 2. 02 MPa and 1. 36 MPa,respectively, and, in turn, the samples from Da-Anshan and Muchengjian in Beijing prove to be lower in this way,that is,0. 773 MPa and 0. 689 MPa. And,furthermore,the frozen adhesive strengths of the different coal samples on the UHMWPE material plate have been found in a range from 0. 159 MPa to 0. 230 MPa with minor difference. As to the granularity and the pore volume distribution of the samples gained from the various coal sampling mines,there exists a great variety due to their respective coal quality,mining and crushing condition,the coal grade and so on. As for the free moisture content,the samples selected from the various coal mines also stand quite different due to their different granularity and pore volume distribution,so that significantly different effects can be resulted on the hydrophillic steel plate. Therefore,the frozen adhesive strength of the coal sample with higher free moisture content can also be greater. In spite of this,the frozen adhesive strength of the various coal samples is not sensitive to the free moisture content of the UHMWPE material due to the hydrophobicity of the material,which can only lead to minor difference. Therefore,the UHMWPE matrix material can be of great help to prevent from and cure of the coal frozen adhesion to the transportation tools and installations in the different regions.