Rheological and electrokinetic properties of composite coal-aqueous fuel based on organic wastewater stabilized by carbon microparticles

Abstract

Man-caused load on sources of industrial and domestic water supply, which causes the discharge of insufficiently treated wastewater, is one of the great environmental problems in Ukraine. The traditional way of solving this problem, associated with the disposal of such waters by adsorption, membrane or catalytic technologies, has a number of disadvantages associated with large volumes and a wide range of pollutants, traditional methods often require preparatory measures, time-consuming, scarce materials and expensive equipment. It would be ideal to create waste-free circulating water supply technologies, but these options are still far from being mass-produced. A promising way to solve these problems is to organize such production cycles, where the disposal of toxic wastewater will be combined with recovery technologies. Industrial and domestic wastewater often contains a significant proportion of the organic component. These are oil products, by-products of organic synthesis, spent lubricating and cooling suspensions, waste from the food, alcohol and pulp and paper industries, dyes and pigments, etc. All this waste is energy saturated and can be separated and used as fuel. However, due to low concentrations in most wastewater, their separation is economically unprofitable. A method is proposed for neutralizing toxic organic wastewater by using it as a dispersion medium for composite coal-aqueous fuel (CAF). The possibility of priming carbon microparticles obtained by preliminary plasma-chemical treatment of an organic dispersion medium to stabilize composite coal-water fuel were investigated. Waste cutting fluid (JCL) was used as an organic dispersion medium; anthracite served as the dispersed phase. A CAF sample was obtained based on anthracite from Ukrainian deposits with a solid phase (W) content of 70 mass. %, and studied its electrokinetic and rheological properties. It has been found that the preliminary plasma-chemical conversion of organic wastewater used as a dispersion medium for composite water-coal fuel significantly improves the operational properties of CAF. The growth of sedimentation stability and the optimization of the effective viscosity are achieved mainly through the implementation of the structural and mechanical factor by increasing the number of contacts with the introduction of a highly dispersed fraction of carbon microparticles and increasing the electrostatic repulsion of the elements of the suspension structure. Thus, the sedimentation stability of the obtained CAF is significantly improved in comparison with conventional anthracite suspensions in organic wastewater and reaches 2 days without the addition of stabilizers. In the future, it is planned to further improve the properties of CAF by introducing stabilizing reagents and dispersants into its composition.