{"title":"Hot-air drying behavior of lignite and quantitative characterization for its surface damage","authors":"T. Zhang, Chenfei Lou, Daoguang Teng, Guosheng Li, Peng Li, Qinghang Yun, Guoli Zhou","doi":"10.1080/07373937.2023.2223621","DOIUrl":null,"url":null,"abstract":"Abstract Cracking and fragmentation problems that occur during lignite drying limit its utilization value. In this study, the dehydration, surface damage, and pulverization behaviors of lignite were investigated under hot-air drying conditions, and the effect of the dewatering process on shrinkage cracking was analyzed. Cracks first appear at the edges of the lignite, then gradually extend inward until they spread over the entire surface of the lignite, before beginning to shrink, and eventually stabilize. The crack rate exhibited three stages: rapid development, shrinkage, and stabilization. The crack rate and shrinkage percentage increased significantly with increase in the drying temperature. The moisture content had a greater influence on the crack rate and shrinkage percentage of the samples than the surface temperature. A uniaxial compression test revealed that lignite with different degrees of dryness exhibited different degrees of breakage. The drying process drives the lignite toward finer grain sizes and, with moisture content below 0.8 g/g, the degree of breakage increases significantly. Thus, the main factor affecting the shrinkage and cracking of lignite was the moisture content. Cracks occurred when the tensile strain caused by shrinkage was greater than the tensile strength of the lignite.","PeriodicalId":11374,"journal":{"name":"Drying Technology","volume":"41 1","pages":"2171 - 2188"},"PeriodicalIF":2.7000,"publicationDate":"2023-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Drying Technology","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1080/07373937.2023.2223621","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Abstract Cracking and fragmentation problems that occur during lignite drying limit its utilization value. In this study, the dehydration, surface damage, and pulverization behaviors of lignite were investigated under hot-air drying conditions, and the effect of the dewatering process on shrinkage cracking was analyzed. Cracks first appear at the edges of the lignite, then gradually extend inward until they spread over the entire surface of the lignite, before beginning to shrink, and eventually stabilize. The crack rate exhibited three stages: rapid development, shrinkage, and stabilization. The crack rate and shrinkage percentage increased significantly with increase in the drying temperature. The moisture content had a greater influence on the crack rate and shrinkage percentage of the samples than the surface temperature. A uniaxial compression test revealed that lignite with different degrees of dryness exhibited different degrees of breakage. The drying process drives the lignite toward finer grain sizes and, with moisture content below 0.8 g/g, the degree of breakage increases significantly. Thus, the main factor affecting the shrinkage and cracking of lignite was the moisture content. Cracks occurred when the tensile strain caused by shrinkage was greater than the tensile strength of the lignite.
期刊介绍:
Drying Technology explores the science and technology, and the engineering aspects of drying, dewatering, and related topics.
Articles in this multi-disciplinary journal cover the following themes:
-Fundamental and applied aspects of dryers in diverse industrial sectors-
Mathematical modeling of drying and dryers-
Computer modeling of transport processes in multi-phase systems-
Material science aspects of drying-
Transport phenomena in porous media-
Design, scale-up, control and off-design analysis of dryers-
Energy, environmental, safety and techno-economic aspects-
Quality parameters in drying operations-
Pre- and post-drying operations-
Novel drying technologies.
This peer-reviewed journal provides an archival reference for scientists, engineers, and technologists in all industrial sectors and academia concerned with any aspect of thermal or nonthermal dehydration and allied operations.