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为了研究复合粒径对松散煤体自燃的影响,利用自制试验装置对复合粒径松散煤体进行了绝热低温氧化试验。采用破碎机制出粒径分别为1~3 mm、3~5 mm、5~7 mm、7~9 mm、9~11 mm及11~13 mm的6种基础煤样。依据基础煤样进行煤炭自燃试验,试验共分为三大组:第一组为各基础煤样的单独氧化试验;第二组为某两基础煤样按1∶1、1∶2、1∶3、2∶1和3∶1比例混合制成复合煤样的氧化试验;第三组为基础煤样1与其他各基础煤样分别按1∶1混合制成复合煤样的氧化试验。在试验过程中,对煤样的温度及试验装置出口氧气体积分数进行监测,得到了各类煤样温度及氧气体积分数的变化规律。研究结果表明:总体上,随煤样加权粒径的增加,煤样的平均氧化升温速率和在同一温度下的耗氧速率减小,耗氧及温升拐点出现的温度也逐渐升高;复合煤样的氧化升温过程受其比表面积和孔隙率的共同影响,当加权粒径小于6.35 mm时,孔隙率的影响较大,当加权粒径大于6.53 mm时,比表面积的影响较大;复合煤样加权粒径越小,各粒径煤样间的相互影响越强;复合煤样中各煤样间的粒径差距越大,煤样间的相互影响越弱。
In order to study the influence of composite particle size on the spontaneous combustion of loose coal, a self-made test device was used to conduct adiabatic low-temperature oxidation test on loosely compounded coal. Six types of coal samples with particle sizes of 1 ~ 3 mm, 3 ~ 5 mm, 5 ~ 7 mm, 7 ~ 9 mm, 9 ~ 11 mm and 11 ~ 13 mm were prepared by crushing. Based on the basic coal samples for coal spontaneous combustion test, the test is divided into three groups: the first group for each of the basic coal sample oxidation test; the second group of two basic coal samples by 1: 1, 1: 2, 1: 3, 2: 1 and 3: 1, and the third group is the oxidation test of the composite coal sample based on the 1: 1 mixture of the basic coal sample 1 and the other basic coal samples. During the test, the temperature of the coal sample and the outlet oxygen volume fraction of the test device were monitored, and the variation rules of the temperature and oxygen volume fraction of various coal samples were obtained. The results show that: with the increase of the coal-particle-weighted particle size, the average rate of oxidation and the rate of oxygen consumption at the same temperature decrease and the temperature at the inflection point of oxygen consumption and temperature rise gradually increases. When the weighted particle size is less than 6.35 mm, the influence of porosity is larger. When the weighted particle size is larger than 6.53 mm, the specific surface area is more affected. The complex The smaller the coal-like particle size, the stronger the mutual influence among the coal samples with different particle sizes. The larger the particle size difference between the coal samples in the coal samples is, the weaker the mutual influence among the coal samples is.