The Main Regularities of Ignition and Combustion of Coal-Water Fuels Produced from Brown, Flame and Gas Coals

Abstract

An experimental investigation was carried out of coal-water fuel (CWF) drops ignition and combustion. CWF examples were produced by using of coal of different metamorphic stages, including brown coal, flame coal, and gas coal. The processes of combustion and ignition of CWF took place in the air. Time-temperature dependences of ignition and combustion processes were obtained; basic stages of CWF combustion were established and investigated; combustion completeness was defined and ash residue structure and properties were investigated during the experimental research. Influence of the working medium temperature on the time duration of each burning stage was defined. Generalization of results was carried out. It is shown, that duration of the volatiles combustion stage doesn’t depend on the medium temperature and stay constant for each of coal grade. Time interval before CWF ignition can be described with power-type dependence, which is identical for all metamorphic stages of coal. The maximum temperature of CWF combustion grows linearly in respect to the medium temperature in the oven.

The Main Regularities of Ignition and Combustion of Coal-Water Fuels Produced from Fat, Non-Baking Coal and Anthracite

“…The completed literature review of the current stage in CWF combustion issues, experimental unit and method of conducting the experimental research, as well as the sample characteristics are described in detail in [1].…”

“…The "TC" abbreviations mean thermocouple. TC1, TC2, and TC3 -are the thermocouples placed in different locations inside coal-water fuel drop and around of it [1].…”

“…The present paper is a continuation of [1], which is focused on determination of the influence produced by the metamorphic stage of the initial coal and the temperature of the oven medium on the qualitative and quantitative parameters characterizing ignition and combustion of an individual drop of coal-water fuel (CWF) in the static air. Research [1] presents the results of experimental investigation into the regularities governing the processes of CWF ignition and combustion for brown (B), flame (D) and gas (G) coal. The current paper analyzes the results of experimental research into the regularities describing the processes of CWF ignition and combustion for fat (F) coal, non-baking (N) coal and anthracite (A).…”

Experimental Investigation of the Influence of Temperature, Coal Metamorphic Stage, and of the Size of Coal–water Fuel Drop on the Fuel Drop Combustion Process

“…From the research, it becomes evident that for the studied drop sizes it is impossible to single out clearly each stage of CWF combustion unlike the case of 5-mm drops (Pinchuk, 2015(Pinchuk, , 2018a. At the same time, it is obvious that combustion of small drops involves the same complex of interrelated physical and chemical processes as in the case of bigger drops.…”

“…A number of papers are devoted to experimental research into the CWF drop combustion processes (Burdukov et al, 1996;Kijo-Kleczkowska, 2011;Liu and Law, 1986;Lyrshchikov et al, 2016;Pinchuk, 2015Pinchuk, , 2018aSmetannikov and Delyagin, 1965). They have determined CWF ignition temperature and combustion stages.…”