添加剂对煤沥青在喹啉不溶物滤饼中渗透性的影响

本工作研究了添加剂对煤沥青的渗透性的影响.本研究采用的添加剂是阳离子型和非离子型添加剂的混合体系.它们对煤沥青的粘度和组成的影响很小,但是渗透性却有大幅度提高,根据达西定律和渗透系数方程对煤沥青浸渍动力学进行了讨论,认为添加剂起到了凝聚QI颗粒、增大有效尺寸和增大孔隙率的作用,改变了滤饼结构.随着其含量的增加,渗透性呈现先增加后减小的规律.通过对2D炭预制体致密化发现,添加剂能够提高煤沥青对高密度的预制体的致密化效率.

Effect of Additive on the Permeability of Coal-tar Pitch Infiltrating Through QI Filter Cake

Particles packing bed composed of quinoline insoluble(QI) always forms on the surface of the preform during impregnation of coal tar pitch.The permeability of coal-tar pitch through the cake is one of the most critical factors to determine the impregnation efficiency.Additive,mixture of an anodic mineral and a nonionic organic compound,was added in the coal-tar pitch to discover its effect on the permeability of the coal tar pitch.The viscosity and compositions of pitch changed little,but the permeability was improved obviously by comparing with the parent coal tar pitch.On the basis of Darcy's Law,the mechanism of the additive was thought as dual-flocculant,which can agglomerate QI particles to bigger aggregations.As a result,the mean size of the particles and porosity of the cake were improved,so the permeability the pitch was enhanced.The permeability increased to a maximum and then decreased with increasing concentration of the flocculants.It was found that the additive could increase the densification efficiency when the high-density 2D carbon preform was impregnated and carbonized,though it seems the carbon yield maybe decrease to some degree.