【摘要】：煤礦火災(zāi)是煤礦五大災(zāi)害之一,煤炭自然發(fā)火是其中的主要因素。在整個煤自燃過程中煤的具體結(jié)構(gòu)變化尚未探究清楚,而低溫氧化是整個自燃的初級階段,在低溫氧化過程中煤不論在宏觀還是微觀都發(fā)生了變化,包括煤的強度、發(fā)熱量、吸氧量、產(chǎn)出氣體、孔隙結(jié)構(gòu)、官能團(tuán)的一系列變化等,這些都與煤的孔隙結(jié)構(gòu)特征密切相關(guān)。由于煤形成的漫長性和成煤地質(zhì)、環(huán)境等條件的巨大差異,導(dǎo)致了煤內(nèi)部孔隙結(jié)構(gòu)復(fù)雜不規(guī)律性。測量孔隙結(jié)構(gòu)的方法很多,其中壓汞法是普遍應(yīng)用的設(shè)備之一,本文采用壓汞儀研究了低溫氧化后察哈素3號煤的孔隙特征變化規(guī)律。為了研究煤樣在低溫氧化后的孔隙特征,實驗選取察哈素3號長焰煤,煤種屬不粘煤(BN31)和少量長焰煤(CY41)并篩選了4組不同粒徑的煤樣分別進(jìn)行25~75℃低溫氧化,然后用壓汞儀進(jìn)行測試,主要研究內(nèi)容有:(1)不同粒徑的煤樣在不同溫度條件下孔隙體積變化規(guī)律研究;(2)不同粒徑的煤樣在不同溫度條件下孔隙比表面積變化規(guī)律研究;(3)低溫氧化過程中煤樣的分形維數(shù)變化規(guī)律研究。通過研究和分析得到了如下結(jié)論:(1)隨著溫度的升高煤樣內(nèi)部的孔隙進(jìn)一步發(fā)育,孔隙體積隨著溫度升高增大;(2)通過分析煤樣內(nèi)部孔隙體積百分比隨著溫度的變化,得出煤樣中4種不同類型孔的孔隙體積百分比隨溫度的變化趨勢,其中小孔和大孔的變化趨勢相反,但煤樣的孔隙體積總體上以小孔和大孔分布為主;(3)煤的總比表面積基本上隨著溫度的升高而增大,影響著煤樣總比表面積的主要是小孔和微孔,二者的比表面積百分比隨溫度的變化趨勢相反;(4)4組煤樣的分形維數(shù)隨溫度變化特征表明:煤樣的分形維數(shù)在25~50℃時隨溫度升高增大,在50~75℃階段又變小,說明煤表面先變粗糙而后變光滑。
[Abstract]:Coal mine fire is one of the five major disasters in coal mine, in which coal spontaneous combustion is the main factor. In the whole process of spontaneous combustion of coal, the specific structural changes of coal have not been clearly explored, and the low temperature oxidation is the primary stage of the whole spontaneous combustion. During the process of low temperature oxidation, both macroscopic and microscopic changes have taken place in the coal, including the strength and calorific value of the coal. Oxygen absorption, gas production, pore structure and a series of changes of functional groups are closely related to the pore structure characteristics of coal. Because of the long formation of coal and the great difference of geological and environmental conditions, the pore structure of coal is complex and irregular. There are many methods for measuring pore structure, among which mercury injection method is one of the most widely used equipment. In this paper, the pore characteristics of Chahasu No. 3 coal after low temperature oxidation are studied by mercury injection apparatus. In order to study the pore characteristics of coal samples after low temperature oxidation, Chahasu 3 long flame coal, which belongs to BN31 and a small amount of long flame coal (CY41), was selected for low temperature oxidation at 2575 鈩，

本文編號：2202424