{"title":"Influences of polymorphism of packed particles on bulk characterizations in fluidization realm","authors":"","doi":"10.1016/j.cjche.2024.07.003","DOIUrl":null,"url":null,"abstract":"<div><p>The characterization of a particle ensemble (rather than a single particle) is of paramount significance to various particle technologies and has long been a fundamental subject in the fluidization realm. However, many of such bulk characterizations as loosely-packed density (<em>ρ</em><sub>bl</sub>), minimum fluidization velocity (<em>U</em><sub>mf</sub>), sphericity (<em>φ</em>), discharge rate through orifice (<em>q</em>), angle of repose (<em>β</em>), and segregation index (<em>S</em>), were found to be poorly reproducible, making the reported results seldom comparable. Since these bulk characterizations started from the packed state of particles, such poor reproducibility was ascribed to the polymorphism of packed particles in this work. We observed that in the fluidized bed, the settled/packed state of particles varied monotonously with the settling rate (<em>α</em>) from complete fluidization to zero. This phenomenon confirmed the polymorphic characteristic of packed particles and further enabled us to systematically disclose/clarify its influences on the aforementioned bulk characterizations. Such influences could be comprehensively and intuitively reflected by the impacts induced by <em>α</em>. With the decrease of <em>α</em>, <em>ρ</em><sub>bl</sub>, <em>φ</em> and <em>q</em> first increased, then decreased, and finally leveled off while <em>U</em><sub>mf</sub> and <em>β</em> showed an opposite trend. On the other hand, <em>S</em> first increased and then remained invariant. As per these findings and definitions of these bulk characterizations, benchmarks were indicated to unify the selection of settled state among future scholars and further make their outcomes become fairly comparable. Additionally, most packed states of the particle ensemble were proved to be metastable with their formation and behavior being identical to those of the amorphous state.</p></div>","PeriodicalId":9966,"journal":{"name":"Chinese Journal of Chemical Engineering","volume":null,"pages":null},"PeriodicalIF":3.7000,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Chinese Journal of Chemical Engineering","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1004954124002489","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}
引用次数: 0
Abstract
The characterization of a particle ensemble (rather than a single particle) is of paramount significance to various particle technologies and has long been a fundamental subject in the fluidization realm. However, many of such bulk characterizations as loosely-packed density (ρbl), minimum fluidization velocity (Umf), sphericity (φ), discharge rate through orifice (q), angle of repose (β), and segregation index (S), were found to be poorly reproducible, making the reported results seldom comparable. Since these bulk characterizations started from the packed state of particles, such poor reproducibility was ascribed to the polymorphism of packed particles in this work. We observed that in the fluidized bed, the settled/packed state of particles varied monotonously with the settling rate (α) from complete fluidization to zero. This phenomenon confirmed the polymorphic characteristic of packed particles and further enabled us to systematically disclose/clarify its influences on the aforementioned bulk characterizations. Such influences could be comprehensively and intuitively reflected by the impacts induced by α. With the decrease of α, ρbl, φ and q first increased, then decreased, and finally leveled off while Umf and β showed an opposite trend. On the other hand, S first increased and then remained invariant. As per these findings and definitions of these bulk characterizations, benchmarks were indicated to unify the selection of settled state among future scholars and further make their outcomes become fairly comparable. Additionally, most packed states of the particle ensemble were proved to be metastable with their formation and behavior being identical to those of the amorphous state.
期刊介绍:
The Chinese Journal of Chemical Engineering (Monthly, started in 1982) is the official journal of the Chemical Industry and Engineering Society of China and published by the Chemical Industry Press Co. Ltd. The aim of the journal is to develop the international exchange of scientific and technical information in the field of chemical engineering. It publishes original research papers that cover the major advancements and achievements in chemical engineering in China as well as some articles from overseas contributors.
The topics of journal include chemical engineering, chemical technology, biochemical engineering, energy and environmental engineering and other relevant fields. Papers are published on the basis of their relevance to theoretical research, practical application or potential uses in the industry as Research Papers, Communications, Reviews and Perspectives. Prominent domestic and overseas chemical experts and scholars have been invited to form an International Advisory Board and the Editorial Committee. It enjoys recognition among Chinese academia and industry as a reliable source of information of what is going on in chemical engineering research, both domestic and abroad.