含水率对煤冻黏强度的影响

Influence of moisture content on coal freezing adhesive strength

煤炭是我国重要的基础能源,而由于滚筒冻黏引起的胶带撕裂、矿车冻黏引起的煤炭回运等问题严重制约了冬季煤矿的安全和高效生产。水作为煤冻结条件的必要因素,对煤的冻黏强度具有重要影响。通过自行设计的冻黏强度测试装置,在温度为-30℃和冷冻时间为3 h的条件下,分别测试了6种不同材料与干基含水率10%~60%煤泥的冻黏特性。实验研究表明,煤的含水率控制在10%以下为宜,此时冻黏强度几乎为0,随着含水率的逐渐升高煤的冻黏强度逐渐增大,当含水率为40%左右时,达到最大值,随着含水率继续增加,煤的冻黏强度反而出现下降。实验结果还表明,普板(Q235)等亲水性金属材料的冻黏强度对煤的含水率比较敏感,而PTFE等疏水性材料的冻黏强度几乎不受含水率影响。PTFE这类材料这种优良特性在高寒地区煤炭运输领域表现了广泛的应用前景,值得进一步深入研究。

Coal is an important basic energy in China. However,the problems of belt tearing caused by coal rollers freezing adhesion,and coal transported back by tramcars freezing adhesion seriously restrict the coal mine safe and efficient production in winter. Water,as an essential factor of coal freeze conditions,has an important influence on coal freezing adhesive strength. Through the freezing adhesive strength test device designed in this study,under the conditions of- 30 ℃ temperature and 3 h freezing time,the freezing adhesive characteristic of six different materials with moisture content 10%- 60% of the coal slime were tested respectively. Studies have shown that if the coal moisture content is controlled under 10%,its freezing adhesive strength is almost zero; with the increase of coal moisture content,its freezing adhesive strength increases gradually; when the coal moisture content is about 40%,its freezing adhesive strength reaches its maximum; with the continued increase of coal moisture content,the coal freezing adhesive strength declines instead. The experimental results also indicate that the freezing adhesive strength of Q235 hydrophilic metal materials is more sensitive to the coal moisture content,and the hydrophobic materials such as PTFE's freezing adhesive strength is almost not influenced by coal moisture content. The excellent characteristic of this kind of materials such as PTFE shows a wide application prospect in coal transportation in a cold area,which needs a further study.