Abstract: During the combustion of coal in the combined heat and power plant (CHP), a very large amount of combustion waste, called further as a fly-ash, is produced. It is typical that fly-ash appears during the combustion process of the fine coal and is transported by a pipeline with support of water as a carrier liquid to a pond storage site, where it is disposed. The pond is localized usually a few kilometers from the CHP, which makes it possible that decrease of friction in such a pipeline can result in energy savings of electricity needed for the pump and water needed as a carrier liquid. In the study an efficient method using a few deflocculants for reducing shear stress, and as a consequence viscosity, is demonstrated. The objective of the paper is to improve the efficiency of the hydrotransport of the fly-ash slurry by adding own designed additives. During the experiments a solids concentration by weight was determined from procured raw material in order to compute the real value occurring in industrial conditions. In addition, the analysis of the particle size distribution was conducted. The Anton Paar MCR 302 electronic rheometer was used to measure the dependence of shear stress and viscosity vs shear rate in the fly-ash existing in the CHP. Another part of the analysis was focused on the additives (deflocculants), to examine their influence on the reduction of the shear stress. The paper proves positive deflocculants impact on the rheological properties of the fly-ash slurry. The results of measurements are presented as figures and conclusions.
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