Heat treatment of a coal layer using microwave energy: numerical study under the conditions of heat release through radiation and convection
V.A. Karelin, V.V. Salomatov
Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
Keywords: microwave radiation, electromagnetic heating, drying, heat radiation, convection, coal, energy costs
Abstract
Coal mined from the surface or underground is rarely suitable for direct use and requires preparation based on physical and/or chemical methods of removing certain components in order to improve the quality of coal to the required level. High humidity leads to a decrease in the energy efficiency of boiler, so the process of fuel drying is a necessary step in coal preparation, and reducing energy costs for moisture removal is an urgent task. One of the ways of moisture reduction is coal treatment with microwave radiation. As compared with other methods, microwave drying has the following features and important advantages: 1) volumetric heating; 2) selective heating (there is no energy absorption in dried areas); 3) low thermal inertia. However, this method requires high power inputs and there is a need to find energy-efficient processing regimes. In the present work, a drying model has been constructed, the optimal regime of layer drying has been found using the finite element method at the example of brown coal from the Talovsky deposit, and energy costs have been determined.
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