Unraveling particle-scale effects in lignite drying: insights from single particles and particle groups.
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| Title: | Unraveling particle-scale effects in lignite drying: insights from single particles and particle groups. |
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| Authors: | Cheng, Cheng1 (AUTHOR), Gao, Mingqiang1 (AUTHOR) gaomq@cumt.edu.cn, Miao, Zhenyong1,2 (AUTHOR) zymiao@cumt.edu.cn, Zhou, Yufang1 (AUTHOR), Wan, Keji2 (AUTHOR), He, Qiongqiong2 (AUTHOR) |
| Source: | International Journal of Coal Preparation & Utilization. 2026, Vol. 46 Issue 6, p1749-1765. 17p. |
| Subject Terms: | *Size reduction of materials, *Heat transfer, *Vaporization, *Activation energy, *Drying apparatus, *Mass transfer, *Computed tomography |
| Abstract: | The drying efficiency of lignite is markedly affected by its particle size. In this regard, the present study explores the drying characteristics of single particles and bed-particle groups. The heat flow channels of the bed-particle groups were modeled using 3D computed tomography to reveal the heat and moisture transfer mechanisms within these groups and to understand the effect of particle scale differences on lignite drying. As the particles became smaller, the trend of the increasing drying rate became more pronounced for single particles. As the particle scale decreased, the relation between drying activation energy (Ea) and particle size followed the equation Ea = 7.665 − 4.384×ln(P + 2.029), whereby particle size reduction effectively promoted lignite drying. However, in the bed-particle-group drying, the drying rate did not incrementally increase as the particle size decreased; however, the average drying rate decreased when the particle size was reduced to 0.5–1 mm. Despite the bed of large particles having numerous heat flow channels and low airflow resistance, it exhibited insufficient gas-solid contact for drying. Although small particles exhibited satisfactory gas-solid contact, they had fewer heat flow channels between particles, resulting in a slower bed heat transfer rate. [ABSTRACT FROM AUTHOR] |
| Database: | Energy & Power Source |
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| Abstract: | The drying efficiency of lignite is markedly affected by its particle size. In this regard, the present study explores the drying characteristics of single particles and bed-particle groups. The heat flow channels of the bed-particle groups were modeled using 3D computed tomography to reveal the heat and moisture transfer mechanisms within these groups and to understand the effect of particle scale differences on lignite drying. As the particles became smaller, the trend of the increasing drying rate became more pronounced for single particles. As the particle scale decreased, the relation between drying activation energy (Ea) and particle size followed the equation Ea = 7.665 − 4.384×ln(P + 2.029), whereby particle size reduction effectively promoted lignite drying. However, in the bed-particle-group drying, the drying rate did not incrementally increase as the particle size decreased; however, the average drying rate decreased when the particle size was reduced to 0.5–1 mm. Despite the bed of large particles having numerous heat flow channels and low airflow resistance, it exhibited insufficient gas-solid contact for drying. Although small particles exhibited satisfactory gas-solid contact, they had fewer heat flow channels between particles, resulting in a slower bed heat transfer rate. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 19392699 |
| DOI: | 10.1080/19392699.2025.2511014 |
