Spraying of Composite Liquid Fuels Based on Types of Coal Preparation Waste: Current Problems and Achievements: Review

This article discusses the atomization of composite liquid fuels. A large group of injectors is considered. A comparative analysis of the atomization characteristics (droplet sizes and velocities, jet opening angles) and the influence of the fuel characteristics (density, viscosity, component composition) and the process parameters (the ratio of the fuel–air mass flow rates, the features of the jet formation) has been carried out. Finally, the most effective types of injectors, which provide for the necessary characteristics of fuel atomization for its combustion, have been determined. The most favorable conditions for the applicability of each type of atomization have been formulated. Possible mechanisms of secondary fragmentation of droplets of composite fuels have been analyzed: those resulting from mutual collisions of droplets in the flux and from the interaction with a solid surface as well as those resulting from thermal overheating in the presence of a phase boundary or a large gradient of component volatility. A conclusion is made about the need of using a synergistic effect of primary and secondary atomization of fuel suspension droplets.

Disposal of fly ash in the production of ash-concrete within the coal-watercoal cluster

Technologies for the disposal of industrial waste in the production of building materials are becoming particularly relevant in connection with the global trend of systematic reduction of the negative anthropogenic impact on the environment. Therefore, one of the goals of the pilot project of the innovative coal-watercoal cluster of housing and communal services is the utilization of ash waste from the combustion of coal-water fuel suspension in the production of building materials. The methodology of ash waste disposal consists in the modification of Portland cement with fine fly ash additives in the production of heavy concrete. As a result of the experiments, the authors proposed a recipe for a concrete mixture with ash waste additives. Tests of control samples of concrete and proposed samples of ash concrete with the addition of ash from the combustion of coal-water slurry were carried out. The brand of the proposed ash concrete in terms of compressive strength, corresponding to the design brand, is determined. Thus, we save the consumption of Portland cement as a binder, which is the most expensive component of concrete. At the same time, we dispose of man-made waste as a safe additive in the production of concrete with specified performance characteristics. The result obtained with the utilization of ash waste as an effective and safe aggregate for heavy concrete can be used in the implementation of a pilot project of an innovative coal-watercoal cluster of housing and communal services. Ash concrete with the addition of ash from the combustion of coal-water slurry can be recommended for use in industrial and civil construction.