Gorobei M. Reduction of negative impact on the environment of man-made pollution by carbon dust

Disertation for the degree of Candidate of Technical Sciences, speciality 21.06.01 “Environmental Safety”, State Ecological Academy of Postgraduate Education and Management, Kyiv, 2020. Specialized Academic Council D 26.880.01. The paper analyzes and summarizes the results of global and domestic studies of man-made air pollution by carbon dust and its negative impact on the environment and humans. And also to analyze the current state of methods and technical means of hydrospray and identify ways to reduce its negative impact on the environment. The causes and regularities of dust formation in mine workings during various technological processes are investigated. The mechanism of deposition of suspended carbon-containing dust on the production soil due to the action of gravitational and electrostatic forces is specified. A mathematical model of the dynamics of the interaction of dust and dispersed water flows in gravitational and electrostatic fields under turbulent, intermediate and laminar modes of air motion has been developed. The mechanical-electrostatic interaction of sprayed water with carbon-containing dust has been studied and a physical model of the process has been developed. The possibility and expediency of complex use of coarsely dispersed liquid and fog-forming curtains are substantiated. The mechanism of capture of suspended carbon-containing dust by liquid droplets in the ventilation stream has been specified. A mathematical model of the dynamics and interaction of dust flows in gravitational and electrostatic fields has been developed. It is established that in the active zone of the torch the efficiency of dust collection is determined by the magnitude and direction of the velocity vector of liquid droplets.Outside the core - the magnitude of the rate of incidence of droplets in turbulent mode and electric forces, the main of which is the field strength of dust and dispersed water jets. It is proposed to define the final efficiency of dust collection as the product of probabilities during the action of three independent forces: dynamic, gravitational and electrostatic. It is shown that in the core the dust concentration can be reduced by 50-80%, and outside the core of the torch due to gravitational forces by 40-60% with a liquid droplet diameter of 200 μm and a dust particle diameter of 10-20 μm. In addition, due to electrostatic forces, the concentration of dust can be reduced by 80 - 90%. It is established that in the core of the torch it is advisable to use a coarse liquid, and outside the core to install an additional fog-forming curtain 5-10 m from the first torch to achieve maximum efficiency of hydrospraying. The parameters of modern means of hydrospraying are substantiated and recommendations on hydrospraying of air in faces and preparatory workings for creation of conditions of more ecological production technologies for reduction of damage to environment are developed. A unique experimental setup has been created to determine the parameters of dust suppression using traditional and new tools. The program and a technique of laboratory researches and mine tests are developed and metrological testing of the experimental equipment is executed. The calculation and matrix of the required number of experiments using modern methods of mathematical planning. Tests conducted in the mines of Donbass confirmed the high efficiency and feasibility of using the proposed injectors. The results of the study were implemented in enterprises of high harmfulness by the dust factor. Key words: coal mining, ecological safety,carbon dust, hydro dedusting, dispersed water jet,water curtain, mathematical model.