Drying behavior of lignite under microwave heating |
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Authors: | Zhanlong Song Liansheng Yao Chuanming Jing Wenlong Wang Chunyuan Ma |
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Affiliation: | National Engineering Laboratory for Coal-Fired Pollutants Emission Reduction, Shandong Provincial Key Lab of Energy Carbon Reduction and Resource Utilization, Shandong University, Jinan, China |
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Abstract: | Because of lignite’s high moisture content, it must be dried before most applications. Microwave radiation may be suitable for efficient drying because of its special heating properties. This study investigated the drying behavior of lignite samples from eastern Inner Mongolia by microwave thermogravimetric analysis. Three stages of microwave drying were observed: preheating, fast weight loss, and falling rate drying periods. Samples’ surface temperatures increased dramatically during preheating, dropped slightly in the second period, and rose again in the final period. The measured surface temperature was <95°C during microwave heating. The overall moisture content decreased more rapidly under higher microwave power. Fine lignite particles (diameter <0.2?mm) and lump samples (particle size 10?mm) dried better than granular lignite (particle size 1–2?mm). The samples also underwent slight natural drying (1–2% point reduction in moisture content) after microwave treatment. The critical moisture content of lignite (11–15% under experimental conditions) was redefined. Energy consumption was analyzed to evaluate the feasibility of the proposed drying process. |
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Keywords: | Energy consumption lignite microwave drying moisture content |
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