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For wide use of coal and oil processing wastes in heat power industry we investigated the structural stability of coal-water slurries (CWS) and coal-water slurries containing petrochemicals (CWSP). Three methods of evaluating slurry stability were considered. The method of evaluation of separation (into layers) of the slurry was chosen to determine the stability of fuel compositions based on bituminous and brown coal, filter cakes of bituminous coals, waste motor, turbine, transformer, compressor oils, oil, oiled mixture and mazut. The experiments shown, that the addition of waste oils (with mass fraction of 10 %) to investigated fuel compositions leads to increase of slurry segmental stability is almost by 2 times.

The present study examines the characteristics of conductive heating (up to ignition temperature) of a composite fuel droplet based on coal, liquid petroleum products, and water. In this paper, we have established the difference between heat transfer from a heat source to a fuel droplet in case of conductive (hot surface) and convective (hot gas) heat supply. The Leidenfrost effect influences on heat transfer characteristics significantly due to the gas gap between a composite fuel droplet and a hot surface.

The paper presents a numerical simulation of composite fuel ignition by a disc-shaped hot metal particle. The study establishes the temperature and the source size limits, which are necessary and sufficient for condensed substance ignition. A diagram with coordinates “a heat flow the amplitude – ignition delay time” has been presented. The diagram shows the area of the sustainable initiate combustion of composite solid fuel at local heating by the source with limited energy capacity.

This paper describes the experimental investigations of the characteristics of heat and mass transfer during the conductive heating of a coal particle. We have established the boundary conditions of combustion initiation, and the conditions of thermal decomposition and solid fuel particles decay, characterized by the temperature of a heat source, and the duration of the respective stages.

Numerical investigation of flammable interaction processes of local energy sources with liquid condensed substances has been carried out. Basic integrated characteristic values of process have been defined – ignition delay time at different energy sources parameters. Recommendations have been formulated to ensure fire safety of technological processes, characterized by possible local heat sources formation (cutting, welding, friction, metal grinding etc.) in the vicinity of storage areas, transportation, transfer and processing of flammable liquids (gasoline, kerosene, diesel fuel).