石油焦焦质特性对水焦浆稳定性影响的实验研究

Experimental study on the Effect of Petroleum Coke Properties on the Stability of Petroleum Coke Water Slurry

为了优化水焦浆的稳定性,实验研究了4种石油焦成浆的静态稳定性,分析了石油焦的可磨性、表面电性和孔隙结构对水焦浆稳定性的影响规律。实验结果表明:4种不同的石油焦,在同等条件下制备水焦浆,静置7 d后,水焦浆在硬沉淀产生量和析水产生量方面呈现较大差异,浆体稳定性悬殊。不同石油焦的可磨性不同,致使各焦粉的粒度分布特征有异,焦粉粒度分布峰高且窄、粒径集中时,颗粒堆积效率低,浆体稳定性差;粒度分布峰扁平且宽、粒径均匀时,不同粒度级间能够达到较好的填充效果,颗粒堆积效率高,成浆浓度高,浆体稳定性好。石油焦颗粒表面荷电量也各不相同,焦粒Zeta电位绝对值越大,焦粒间的静电排斥力越强,越能有效的阻碍颗粒间的凝聚,从而使颗粒在浆体体系中得以稳定分散,使浆体呈现较好的静态稳定性。石油焦微观孔隙结构特征与水焦浆的稳定性之间存在一定的内在联系,石油焦比表面积越小、平均孔径越大,水焦浆的稳定性就越好。

In order to optimize the stability of petroleum coke water slurry(PCWS),the static stability of slurries made from four kinds of petroleum coke was studied experimentally,and the effects of the grindability,surface electrical properties and pore structure of petroleum coke on the stability of PCWS were investigated in this paper.The results showed that the stability of PCWSs made with different petroleum coke on the same conditions after a static storage of 7 days differed from each other,which was reflected by the yield of hard precipitation and water seepage.The grindability of different petroleum coke was different,resulting in different particle size distribution characteristics.The stability decreased as the particle size distribution was concentrated and the particle accumulation efficiency was low.On the contrary,the stability improved as the particle size distribution was average in a large range leading to a better filling effect between different granularity levels.The electric charge of petroleum coke particle surface was not identical.The larger the absolute value of Zeta potential,the greater the electrostatic repulsion between petroleum coke particles,which could more effectively block the interparticle cohesion.So that the particles could disperse in the slurry system stably and the slurry could present good static stability.There was a certain internal relation between the characteristics of petroleum coke micropore structure and the stability of PCWS.The smaller the surface area of petroleum coke and the larger the mean pore diameter,the better the stability of PCWS.