Effects Of Dispersants On The Preparing Of Coal Pitch Water Slurry And Their Interaction

The utilizing of coal is becoming a very important issue for its large reservation. The coal pitch is main product in coking process, which has a large production. However, more ways are pressed to be found to make more use of it, because its utilization is not good enough.The efficient use of coal pitch can help our country get rid of energy crisis. The direct combustion of coal pitch has a low efficiency, which by the way, causes environmental pollution at the same time. The coal pitch slurry and emulsified asphalt have solved this problem to a certain extent, but the utilizing of coal pitch is staying low end. The coal pitch water slurry (CPWS) was brought up by our research team, which is prepared by dispersants, water and coal pitch powder.Surface properties of coal pitch were characterized by elemental analysis, industry analysis, SEM-EDS, XPS and other means of analysis in order to understand the elements of coal composition, surface morphology and distribution of surface functional groups. Four kinds of anionic dispersants, anthraquinone-2-sulfonate (abbreviated NA), ethyl naphthalene sulfonate (abbreviated SN), sodium dodecyl benzene sulfonate (abbreviated SDBS) and sodium dodecyl sulfate (abbreviated SDS), five kinds of cationic dispersants, octadecyl trimethyl ammonium chloride (abbreviated STAC), cetyl dimethyl benzyl ammonium chloride (abbreviated HDBAC), cetyltrimethyl ammonium chloride (abbreviated CTAC), phenyl trimethyl ammonium chloride (abbreviated PTAC) and tetramethyl ammonium chloride (abbreviated TMAC), and JC-01 were investigated by testing surface tension and contact angle on coal pitch’s surface. Based on these study results, spreading coefficient and adhesion work were calculated, and Zisman theory was proved to be fitting for this wetting system. The adsorption amount and Zeta potential of STAC, CTAC and HDBAC on coal pitch’s surface was studied by UV spectrophotometry and Zeta potentiometer. All dispersants were used to prepare CPWS in order to find the appropriate ones.The results showed that the main element of coal pitch is Carbon, in an amount of more than 90%. Dispersants used in the experiment can reduce surface tension of the solution. Linear dispersants had better wettability on coal pitch’s surface than polycyclic dispersants. The adsorption amount of HDBAC on coal pitch’s surface is greater than that of STAC and CTAC, and the adsorption amount of CTAC is the smallest. The Zeta potential of HDBAC on coal pitch’s surface is the highest in three dispersants, and CTAC is the smallest. STAC can be used for preparing CPWS while the other two can’t. There is certain regularity in the match between wetting, adsorption, Zeta potential and CPWS preparation. Apparent viscosity of CPWS increased with the increasing of slurry concentration when dispersant’s amount kept a certain value. When slurry concentration was constant, apparent viscosity of CPWS increased with the increasing of dispersant’s amount. Apparent viscosity decreased with the increasing of shear rate, indicating that the CPWS was pseudoplastic fluid. CPWS has the best rheology with dispersant amount 1.2% and 1.4% or slurry concentration 66% and 67%.