煤泥水压滤滤饼孔隙结构特征研究

Pore structure characteristics of filter cake in coal slurry water pressure filtration

滤饼的孔隙结构是影响煤泥水过滤效果的关键因素,但煤泥滤饼孔隙结构测量中存在滤饼结构易损坏和煤颗粒与孔隙难区分的难题。为了深入研究煤泥水压滤滤饼孔隙结构特征,建立了煤泥滤饼固化装置与方法,利用偏光显微镜研究了入料中-0.074 mm粒级含量、过滤压力对煤泥滤饼孔隙结构的影响。结果表明:随着入料中-0.074 mm粒级含量增加,滤饼孔径、孔面积和孔隙率降低速率变缓,孔隙孔径分布范围变窄,孔隙构成中的小孔径孔隙所占比例增加,孔隙截面边界分形维数变大,滤饼孔隙截面边界更曲折,孔隙结构更复杂;煤泥水过滤压力增加主要压缩滤饼中的大孔径孔隙,过滤压力越大,滤饼孔隙压缩越严重,滤饼孔隙率越低,孔隙截面边界分形维数越大,滤饼孔隙边界越曲折,孔隙结构越复杂。

The pore structure of filter cake is the key factor influencing coal slurry water filtering effect,but filter cake structure is easily damaged and coal particles and pores become indistinguishable during the coal slime filter cake measurement. In order to study the pore structure characteristics of filter cake in coal slurry water pressure filtration,this paper established a coal slime filter cake solidification device and method. Effect of-0. 074 mm particles content and filtration pressure on coal slime filter cake pore structure were investigated using polarizing microscope. The results show that an increasing amount of-0. 074 mm particles content results in smaller decreasing rate of pore diameter,pore area and porosity,narrower pore diameter distribution,and larger proportion of small pores in the constituents of porosity. It also leads to increasing fractal dimension of filter cake pore section edge,more zigzag pore section edge and more complicated pore structure. Increase in coal slime water filtration pressure prior compresses filter cake large pores. As the filtration pressure rises,filter cake pore compresses,porosity descends and fractal dimension of pore section edge ascends. In addition,it complicates the pore structure with more zigzag pore section edge and more irregular pore shape.