Powder Technology最新文献

{"title":"Methane dry reforming in a microwave heating-assisted dense fluidized bed","authors":"Mojtaba Mokhtari,&nbsp;Jaber Shabanian,&nbsp;Jamal Chaouki","doi":"10.1016/j.powtec.2024.120444","DOIUrl":"10.1016/j.powtec.2024.120444","url":null,"abstract":"<div><div>Dry reforming of methane helps mitigate greenhouse gas emissions as a global issue. This technology produces syngas, which can be converted into valuable chemicals, e.g., synthetic fuels. Electrification of this technology by adopting a microwave heating-assisted dense fluidized bed dry reformer can enhance its sustainability. In the present study, we developed a model to assess the performance of this reactor. This first-of-its-kind model employed an Eulerian-Granular multiphase model in conjunction with Maxwell's equation to simulate catalyst particles' hydrodynamics and microwave-induced heating while combined with the corresponding reactions to predict the overall performance of the dense fluidized bed reactor. We validated the model with experimental data from literature and performed a set of parametric studies with the validated model. This model holds promise for identifying the optimal operating conditions of the selected reformer, i.e., a crucial step toward commercialization of microwave heating-assisted dry reforming of methane.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"449 ","pages":"Article 120444"},"PeriodicalIF":4.5,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of mechanical milling time on powder characteristic, microstructure, and mechanical properties of AA2024/B4C/GNPs hybrid nanocomposites","authors":"Müslim Çelebi,&nbsp;Aykut Çanakçı,&nbsp;Serdar Özkaya","doi":"10.1016/j.powtec.2024.120439","DOIUrl":"10.1016/j.powtec.2024.120439","url":null,"abstract":"<div><div>In this study, hybrid nanocomposites consisting of an AA2024 matrix reinforced with 1 wt% B₄C nanoparticles and 1 wt% GNPs were produced using a powder metallurgy method assisted by mechanical milling. This study aimed to systematically investigate the effect of grinding time on powder characteristics (particle size, microhardness, and morphology) as well as microstructure, densification, and mechanical performance to optimize processing conditions for superior material properties. Microstructural characterization of powders and bulk samples were carried out using a SEM device equipped with EDS. The results indicate that with increasing milling time, the particle size significantly decreased, while the particle hardness increased substantially. Additionally, the sample milled for 8 h achieved the highest relative density among the hybrid nanocomposites, reaching a value of 95.3 %. Mechanical tests revealed that after 8 h of milling, the hardness and tensile strength reached peak values of 164 HB and 314 MPa, corresponding to increases of 56 % in hardness and 43 % in tensile strength compared to the unreinforced alloy. The analysis results confirm that the optimal properties were obtained after 8 h under all conditions.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"449 ","pages":"Article 120439"},"PeriodicalIF":4.5,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterisation of a continuous blender: Impact of physical properties on mass holdup behaviour","authors":"Hikaru Graeme Jolliffe ,&nbsp;Maria A. Velazco-Roa ,&nbsp;Luis Martin de Juan ,&nbsp;Martin Prostredny ,&nbsp;Carlota Mendez Torrecillas ,&nbsp;Gavin Reynolds ,&nbsp;Deborah McElhone ,&nbsp;John Robertson","doi":"10.1016/j.powtec.2024.120440","DOIUrl":"10.1016/j.powtec.2024.120440","url":null,"abstract":"<div><div>Continuous blenders are a key unit operation in Continuous Direct Compaction, a route to solid oral dosage forms that is receiving significant interest. Mass holdup in these blenders is a crucial variable; understanding how it is influenced by material properties, equipment configuration and process settings is key. The present work evaluated a Gericke GCM-450 blender for range of outlet weir aperture geometries (angled or horizontal), material properties (pure components and blends) and process settings (throughput and impeller speed). Results show opposing mass holdup behaviour depending on weir choice, material density and flowability, likely linked to the propensity of the material to form an inclined powder surface that matches – or does not – the chosen weir geometry. The present work underscores the need for fundamental process phenomena understanding, especially when insight is sought for how blender performance varies across multiple dimensions (throughput, impeller speed, material properties) and discrete equipment choices (weir geometry).</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"449 ","pages":"Article 120440"},"PeriodicalIF":4.5,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mass discharge rate of granular flow in eccentric silos with variable side wall friction","authors":"Ge Sun ,&nbsp;Quan Chen ,&nbsp;Ran Li ,&nbsp;Tongtong Mu ,&nbsp;Hui Yang","doi":"10.1016/j.powtec.2024.120438","DOIUrl":"10.1016/j.powtec.2024.120438","url":null,"abstract":"<div><div>There are many studies on the effect of side wall friction on mass discharge rate (MDR), but the physical mechanism is lacking. In this paper, by changing side wall friction of eccentric silos, the relationship between macroscopic MDR and microscopic frictional coefficient was established, and the regulation of MDR up to a range of 40 % was realized. Furthermore, it is revealed that the variation of MDR is caused by the change in geometric structure of free-fall arch (FFA). In addition, the velocity of particles on FFA is the same under different MDR. The reason is that under high frictional coefficient, the gravitational potential energy of particles is more dissipated in the rotational motion caused by resistance. This work explains for the first time the mechanism of the frictional coefficient on MDR, and provides a data reference for improving the theoretical model of MDR.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"449 ","pages":"Article 120438"},"PeriodicalIF":4.5,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulating breakage by compression of iron ore pellets using the discrete breakage model","authors":"Horacio A. Petit ,&nbsp;Alexander V. Potapov ,&nbsp;Luís Marcelo Tavares","doi":"10.1016/j.powtec.2024.120433","DOIUrl":"10.1016/j.powtec.2024.120433","url":null,"abstract":"<div><div>Simulation of breakage embedded in the discrete element method (DEM) has evolved significantly in recent years, taking advantage of both greater computing power and novel approaches that have become available in both commercial and open-source packages. This work analyzes in detail the simulation of breakage using the discrete breakage model (DBM) in the commercial software Ansys Rocky. Breakage of iron ore pellets under slow compression was studied. After the selection of suitable contact parameters for the pellets, described as polyhedral particles, the model is used to describe their breakage considering fully resolved fragments from the beginning of the simulation. The effects of contact model, time step and number of elements on the ability of the model to represent average breakage response of iron ore pellets under compression is analyzed. An approach was then used to account for the variability in the breakage characteristics of the pellets, which provided a valid description when applied to another pellet sample, also showing capability to describe the size-scale effect on the breakage energy of pellets when applied to pellets of different sizes.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"449 ","pages":"Article 120433"},"PeriodicalIF":4.5,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of particle shape in sheared granular media: Roundness and elongation","authors":"Usman Ali,&nbsp;Mamoru Kikumoto","doi":"10.1016/j.powtec.2024.120436","DOIUrl":"10.1016/j.powtec.2024.120436","url":null,"abstract":"<div><div>Particle shape is an intrinsic characteristic of soil particles that significantly influences mechanical responses. In this investigation, a meticulously calibrated and validated two-dimensional discrete element method (DEM) model of a biaxial shearing test was employed to simulate the shearing response of forty distinct particle shapes. The systematic evolution of particle roundness (R) and aspect ratio (AR) was achieved by utilizing idealized polygonal-shaped particles, aiming to comprehend their effects on the macro and micromechanical behaviors of granular materials. The results suggest that a reduction in R limits free rotations and enhances interlocking, thereby promoting relatively stable force transmission between particles and leading to a monotonic increase in shear strength. However, this effect diminishes as particles become more elongated. Conversely, a decrease in AR from 1.0 (increased elongation) constrains particle rotations, increases the coordination number, and enhances fabric anisotropy initially resulting in increased overall shear strength, reaching a maximum before exhibiting a decreasing trend, indicative of non-monotonic variation. For high elongations, notable fabric anisotropy impedes clear force transmission between particles thus facilitating interparticle sliding and overall strength diminishes. The extent to which AR impacts depends on the angularity feature of particles. Finally, a nonlinear equation has been proposed to predict the variation in critical state shear strength of granular samples, based on the R and AR values of the constituent particles.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"449 ","pages":"Article 120436"},"PeriodicalIF":4.5,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of a new three-phase fluidised bed flotation column for industrial experiment study","authors":"Ning Han ,&nbsp;Yifei Li ,&nbsp;Zhiyuan Zhang ,&nbsp;Jikang Han ,&nbsp;Peng Chen ,&nbsp;Yanfeng Li","doi":"10.1016/j.powtec.2024.120435","DOIUrl":"10.1016/j.powtec.2024.120435","url":null,"abstract":"<div><div>Three-phase fluidized bed flotation column (TFC) is a new type of separation flotation method with high efficiency and low energy consumption. In this paper, the industrial experimental effect of TFC is investigated. The influence of operating parameters on the flotation separation effect was investigated by adjusting the operating parameters such as gas velocity, liquid velocity, and bed height. In addition, when the sampling depth and sampling radius are increased, the ash content in the selection zone increases with it. The relationship between the amount of mid-coal circulation and the ash content was also investigated. The ash content of refined coal gradually decreased from 10.28 % to 9.28 % when the amount of middle coal circulating was increased from 0 % to 50 % of the feed. This study explores the separation effect of TFC from industrial experiment perspective, which lays a good foundation for future industrial-scale applications.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"449 ","pages":"Article 120435"},"PeriodicalIF":4.5,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of impeller speeds on the nanobubbles flotation efficiency of ultrafine coal particles","authors":"Hanyue Jiang ,&nbsp;Haichang Yang ,&nbsp;Yaowen Xing ,&nbsp;Yijun Cao ,&nbsp;Xiahui Gui","doi":"10.1016/j.powtec.2024.120431","DOIUrl":"10.1016/j.powtec.2024.120431","url":null,"abstract":"<div><div>Ultrafine particles exhibit poor flotation behavior due to the low collision efficiencies with conventional gas bubbles. Introducing nanobubbles are expected to improve the collision probability of ultra-fine particles with bubbles. However, it remains unclear whether nanobubbles can enhance flotation at high impeller speeds during flotation process as strong turbulence may scour away the nanobubbles from solid-liquid interface of particles. This study investigates the influence and the underlying mechanism of nanobubbles on flotation performance of ultrafine coal particles under varying impeller speeds. Specifically, the surface nanobubbles (SNBs) and bulk nanobubbles (BNBs) were utilized respectively, which were produced based on the temperature difference method and hydrodynamic cavitation, and characteristized by atomic force microscopy (AFM) and nanoparticle tracking analysis (NTA), respectively. The formation of ultrafine coal particle aggregates at different impeller speeds was analyzed through laser particle size analyzer (LPSA) and high-speed camera imaging. Result showed that as the impeller speed increases, the radius of the aggregates increases, and the number and radius of aggregates in SNBs/BNBs slurries is significantly larger than that in conventional slurry at varying impeller speeds from 1200 to 2800 rpm, which is consistent with the increased flotation recoveries and flotation rates. It is demonstrated that nanobubbles remain stable even at high impeller speeds, and thus promote aggregation and thereby enhance flotation performance. The findings of this study provide theoretical support and valuable insights for ultrafine particle separation technologies.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"449 ","pages":"Article 120431"},"PeriodicalIF":4.5,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical investigation on compaction operations of railway gravel ballast based on DEM-MBD coupling method","authors":"Zhihai Zhang ,&nbsp;Hong Xiao ,&nbsp;Qiang Liu ,&nbsp;Yang Wang ,&nbsp;Zhongxia Qian ,&nbsp;Mahantesh M. Nadakatti","doi":"10.1016/j.powtec.2024.120428","DOIUrl":"10.1016/j.powtec.2024.120428","url":null,"abstract":"<div><div>Compaction is an essential process in the maintenance of ballasted railways. However, unreasonable operating parameters can reduce compaction efficiency and increase maintenance costs. Previous studies have hardly addressed the impact of compaction on improving the mechanical properties of the ballast bed. In the study, the dynamic equations of compaction are established, and a novel model of compaction based on DEM-MBD coupling method is developed. Furthermore, the parameters of the compaction are optimized from a macro and micro perspective. The research results show that the compaction mainly increases the coordination number of the ballast in the upper area of the ballast shoulder, and the maximum growth rate is 17.45 %. The study reveals that there is no positive correlation between the compacting effect and the excitation frequency. The optimal frequency range for compaction is 25–32 Hz. This study can provide key theoretical support for the parameter selection of on-site compaction for line maintenance.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"449 ","pages":"Article 120428"},"PeriodicalIF":4.5,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CFD-DEM simulation study on the bed dynamics of a binary mixture with super-quadric particles in a fluidized bed","authors":"Ju Wang ,&nbsp;Guirong Bao","doi":"10.1016/j.powtec.2024.120425","DOIUrl":"10.1016/j.powtec.2024.120425","url":null,"abstract":"<div><div>In biomass thermal conversion processes such as pyrolysis and gasification, biomass often takes on a cylindrical shape. However, most previous studies have modeled biomass as spherical, leaving the fluidization and mixing behaviors of non-spherical biomass particles with approximately spherical bed materials insufficiently explored. To bridge this gap, a super-quadratic particle model coupled with CFD-DEM was used to explore the fluidization characteristics and mixing dynamics of non-spherical binary mixtures. The numerical model successfully validated the pressure drop and spatial distribution within the binary mixture. The results indicate that particle mixing is primarily driven by the rise and movement of bubbles. The large aspect ratio of the cylindrical particles, combined with the narrow thickness of the 2D rectangular fluidized bed, leads to a significant interlocking effect during fluidization. This interlocking hinders both fluidization and mixing, resulting in poor overall performance for non-spherical particles. At a low superficial velocity (<em>U</em>_<em>g</em>), only the cylindrical particles in the lower part are fluidized as a result of the rising central bubble. The two particle types achieve effective mixing as the <em>U</em>_<em>g</em> rises to a high value. The mixing index increases from 0.78 to 0.94 as the <em>U</em>_<em>g</em> increases from 1.8 to 2.1 m/s. However, the stacking pattern of cylindrical particles creates a dead zone at the bed bottom, occupied solely by spherical particles, which limits local bed mixing and fluidization. As the <em>U</em>_<em>g</em> increases from 1.8 to 2.1 m/s and the dimensionless inventory height increases from 0.6 to 1.0, the axial dispersion coefficient of the cylinders increases from 1.17<span><math><mo>×</mo></math></span>10⁻³ to 4.35<span><math><mo>×</mo></math></span>10⁻³ m²/s and from 1.91<span><math><mo>×</mo></math></span>10⁻³ to 9.22<span><math><mo>×</mo></math></span>10⁻³ m²/s, respectively. This study provides new insights into the behavior of non-spherical particles, offering potential avenues for optimizing chemical engineering processes.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"449 ","pages":"Article 120425"},"PeriodicalIF":4.5,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}