One
of the promising directions for improving the environmental,
technical, and economic efficiency of coal-fired thermal power plants
is the use of the multicomponent fuels based on coal and combustible
liquids. Such fuels, as a rule, are called coal–water slurries
containing petrochemicals (CWSPs). The typical wastes of coal enrichment,
low-grade coals, oil production, and oil refining wastes as well as
used flammable liquids, for example oils, can be included in the fuel
composition. To date, mathematical models have not been developed
for predicting the effective conditions for the ignition of promising
CWSPs at minimum ambient temperatures and with short ignition delay
times. This problem was solved in the present work. On the basis of
the experimental results, three modes of physical and chemical transformations
were established when heating single particles of the composite fuel.
The first one is the intensive thermal decomposition of the coal component
after evaporation of the liquid components of the fuel. Then goes
the gasification of coal under the boiling conditions of the liquid
components followed by the heterogeneous combustion of the solid residue.
The third mode is the ignition of the gas mixture in the vicinity
of the fuel particle and initiation of heterogeneous combustion of
the solid residue. The temperature ranges of the environment were
determined under which the detected modes of the physical and chemical
transformations occur. The obtained experimental data became the basis
for the development of a predictive mathematical model of the transformations
that occur when heating a composite fuel with different characteristics
of the components. It takes into account the interrelated physical
and chemical processes: inert heating, evaporation, thermal decomposition,
and exothermic reaction. The developed mathematical model and the
results of the theoretical studies make it possible to establish the
influence of the characteristics of the fuel components and the conditions
of its heating on the three identified modes of physical and chemical
transformations.