| How to use the coal resources efficiently and reasonable is becoming more and more important with the energy crisis becoming more and more intensity. The coking coal and lignite coal are important coal resource in our country, how to fast and efficiently drying the coal resources has become a major issue. Based on this, the paper carried out many drying experiment to study the coking coal and lignite, study the drying characteristics of coking coal, providing a theoretical basis and experimental data for further enlarge the drying system.Firstly, this paper studied the drying characteristics of coking coal under different conditions in a fixed bed, discovered the coking coal drying rate increased with the drying temperature rising and the particle size decreasing.The drying rate under the CO2 atmosphere is higher than N2 and simulated flue gas atmosphere. Found that the Midilli-Kucuk model can best describe the coking coal isothermal drying process by using the thin layer drying model theory. The drying activation energy is calculated by the Arrhenius experience formula and the second Fick diffusion theorem.Then, we studied the drying characteristics of the lignite in the auger drying experiment bench, found the cool drying rate increased with the rising of the bench temperature and the velocity of the drying medium and the decreasing of lignite particle size. Modified Page model was found can best describe the lignite isothermal drying process in the auger drying experiment bench by using the thin layer drying model theory.Finally, this paper studied the drying characteristics of the lignite in a rotary kiln. Masured the temperature distribution in the rotary kiln when the lignite was drying. analyzed the lignite moisture content at every temperature measuring point, calculated the heat transfer coefficient in the rotary kiln with the energy conservation. Discovered the heat transfer coefficient increased with rising of the rotary kiln temperature and the rotary kiln speed. |
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