Assessing the moisture migration during microwave drying of coal using low-field nuclear magnetic resonance. Issue 5 (4th April 2018)

• Record Type: Journal Article
• Authors: Li, He; Lin, Baiquan; Hong, Yidu; Liu, Tong; Huang, Zhanbo; Wang, Rui; Wang, Zheng
• Is Part Of: Drying technology. Volume 36:Issue 5(2018)
• Page Start: 567
• Page End: 577
• Publication Date: 2018-04-04
• Subjects: Bound water -- free water -- low-field nuclear magnetic resonance -- microwave drying -- moisture migration; Drying -- Periodicals; Desiccation; 660.28426
• DOI: 10.1080/07373937.2017.1349136
• Languages: English
• ISSNs: 0737-3937

Abstract

ABSTRACT: Microwave drying of coal has the advantage of volumetric and selective heating, which saves energy and time. However, comprehensive assessment of the moisture migration during microwave drying is lacking. In this study, the low-field nuclear magnetic resonance (LF-NMR) was used for moisture characterization during microwave drying. Moisture migration occurs first in larger pores, whereas the smaller pores appear to remain water-saturated. As the microwave power increases, the drying capacity and drying rate both increase because high-power microwave can open the blind pores to promote moisture seepage. Furthermore, moisture migration during microwave drying is usually directional (i.e., along the bedding plane). The LF-NMR method provides a framework for the determination of moisture migration of coals.