Article
Engineering, Chemical
Tian Nan, Jesse Zhu
Summary: The hydrodynamics of inverse liquid-solid circulating fluidized bed were studied comprehensively, revealing specific flow patterns and solid distribution laws, influenced by factors such as particle size and flow velocity.
CHEMICAL ENGINEERING SCIENCE
(2022)
Article
Engineering, Chemical
Tian Nan, Jesse Zhu
Summary: An inverse liquid-solid circulating conventional fluidized bed (I-CCFB) is realized by injecting particles from the top of a conventional liquid-solid fluidized bed, which is operated in a newly developed circulating conventional fluidization regime. The I-CCFB can achieve a higher solids holdup compared to both conventional and circulating liquid-solid fluidized beds. A new flow regime map is presented, including the I-CCFB and a variety of other liquid-solid fluidized beds.
Article
Engineering, Environmental
Chengxiu Wang, Zhihui Li, Zeneng Sun, Xingying Lan, Jinsen Gao, Mao Ye, Jesse Zhu
Summary: A two-step Otsu's method was used to analyze the gas-solids flow field in a TFB at different axial levels. The results showed that the solids holdup increased with increasing H0/D ratio, while the mass and volume fraction of cluster clouds decreased. The study also extracted parameters related to cluster cores and found that clusters had equal chances to move towards the center and the wall of the TFB at a low H0/D ratio with high Ug.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Chemical
Jinding Hu, Daoyin Liu, Heng Li, Cai Liang, Xiaoping Chen
Summary: This study investigated the solid circulation rate in pressurized circulating fluidized beds under different conditions, and obtained an empirical equation relating the solid circulation rate to the operating parameters, which is helpful for the design and operation of PCFBs.
Article
Engineering, Multidisciplinary
Fria Hossein, Massimiliano Materazzi, Matteo Errigo, Panagiota Angeli, Paola Lettieri
Summary: This paper describes the application of ultrasound techniques in solid-liquid fluidized beds, including the measurement of velocity profiles, particle size distribution, and solids volume fraction. The results indicate that ultrasound techniques are important for real-time characterization of highly concentrated solid-liquid systems.
Article
Engineering, Chemical
Yangfan Song, Wenwen Hao, Hongwei Chen, Qi Yu, Lou Zhu, Xinxin Wang, Chao Zhao
Summary: This study investigated the hydrodynamic characteristics of a novel liquid-solid circulating fluidized bed through numerical simulation, revealing the effects of pulsating liquid flow and particle properties on the bed performance. The results showed that the addition of pulsating liquid flow enhanced radial particle motion, interphase mixing degree, and mass transfer efficiency.
ADVANCED POWDER TECHNOLOGY
(2022)
Article
Engineering, Environmental
Tove Djerf, David Pallares, Filip Johnsson, Gaetano Sardina, Henrik Strom
Summary: This study investigates the back-mixing of solids in the transport zone of large-scale circulating fluidized bed (CFB) boilers and identifies the core-to-wall layer mass transfer as the governing mechanism. Pe-numbers may not straightforwardly describe lateral solid dispersion, and a Pe-number < 26 is needed to match the measured back-mixing rates in large-scale CFB boilers. A mathematical expression for the core-to-wall layer mass transfer coefficient based on a Sherwood number correlation shows better agreement with large-scale measurements than expressions in the literature.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Engineering, Chemical
Xiaolai Zhang, Gongpeng Wu, Yan He, Xuejun Yu
Summary: Particle cluster motions in a multistage circulating fluidized bed were experimentally studied, with characteristics and dynamic parameters analyzed. Results showed cluster motions weaken and breakup increases in the enlarged section, affected by gas turbulence and collision. Cluster frequency, duration, and time fraction decrease with increasing gas velocity but increase with increasing solid mass flux. Cluster size is reduced in the enlarged section, with motion restricted under low solid loading.
PARTICULATE SCIENCE AND TECHNOLOGY
(2022)
Article
Engineering, Chemical
Jia Wei Chew, W. Casey Q. LaMarche, Ray A. Cocco
Summary: As we celebrate the 100th anniversary of the commercialization of the fluidized bed reactor, it is evident that fluidized bed technology has undergone significant advancements in the past century. With the development of sophisticated models, experimentation techniques, and statistical tools, as well as the utilization of computational platforms and AI, the application of fluidized bed technology is expected to become more cost-effective and efficient.
Article
Mechanics
Kenan Xi, Hao Wang, Youjun Lu
Summary: Supercritical water circulating fluidized beds (SCWCFBs) were investigated using a two-fluid model to study flow dynamics. The study focused on various factors such as flow velocities, solid circulation rates, pressures, and temperatures. The results showed similarities between SCWCFB risers and traditional gas-solid risers. The void fraction distributions ranged from 0.85 to 0.95, with lower values at the bottom and near the walls, and higher values at the top and center. The particle velocities exhibited annular-core flow structures, with upward velocities near the axis and downward velocities near the walls. The fluid paths were tortuous at low velocities but straight at high velocities. The particle drag forces were around 0.7-0.8 times the particle weights. The effects of pressures on flow dynamics were attributed to changes in density and viscosity, affecting the fluid's ability to carry particles.
Article
Energy & Fuels
Diana Carolina Guio-Perez, Marlene Bonmann, Tomas Bryllert, Martin Seemann, Jan Stake, Filip Johnsson, David Pallares
Summary: The aim of this work is to demonstrate the value of radar technology for studying experimentally the solids flows in gas-solids fluidized beds. The work presents original results regarding the solids concentration and velocity acquired in a non-intrusive manner from a cold flow model. The radar technique applied in this work is a promising technique for detailed characterization of the solids flow in fluidized beds, offering high spatial and temporal resolutions, allowing the determination of both solids velocity and concentration, and having a reasonably high penetration depth.
Article
Engineering, Chemical
Zeneng Sun, Bowen Han, Tianzi Bai, Shahzad Barghi, Jesse Zhu
Summary: The study found that as the sand volume fraction increases, the minimum fluidization velocity decreases in two different binary particle systems. Bubble size and rise velocity increase along the bed height, with a linear correlation between the two.
CHEMICAL ENGINEERING SCIENCE
(2022)
Article
Engineering, Chemical
Chengxiu Wang, Xiao Yang, Min Wang, Jiazhi Zhang, Xingying Lan, Jinsen Gao, Mao Ye, Jesse Zhu
Summary: This study comprehensively investigates particle velocity in a two-dimensional circulating fluidized bed under different solids circulation rates, showing that the lateral profile and axial distribution of particle velocity vary with different solids loading conditions. The empirical correlations established in this work can predict both axial and lateral particle velocities, and the relationship between particle velocity and solids holdup works better for low solids circulation rates. Different fluid mechanisms may be suggested for low and high solids flux conditions based on the analysis.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2021)
Article
Engineering, Chemical
Jingya Fu, Xinyu Pan, Zeneng Sun, Ruoting Liu, Ying Zheng, Jesse Zhu
Summary: This study proposed and experimentally studied a new type of liquid-solid fluidized bed, called circulating conventional fluidized bed (CCFB), which operates below particle terminal velocity. The hydrodynamic behavior of a liquid-solid CCFB was systematically investigated, and it was found that liquid-solid fluidization with external particle circulation could be achieved below the particle terminal velocity. The axial distribution of local solids holdup was fairly uniform in a wide range of liquid velocities and solids circulation rates. Compared with conventional fluidization under similar conditions, the average solids holdup was significantly increased in CCFB. Additionally, the effect of particle properties and operating conditions on bed behavior was investigated.
Review
Energy & Fuels
Hengjun Gai, Peiyi Yang, Qiang Zhang, Mengqi Lin, Hongbing Song, Meng Xiao, Tingting Huang, Quanhong Zhu
Summary: Circulating fluidized bed reactors are widely used in the energy industry for gas-solid reactions. They can be classified into two categories based on fluidization regimes: dilute-dense and dual-dense. The concept of dual-dense gas-solid circulating fluidization has not been well understood, hindering its commercial application. This review provides a detailed analysis of the dual-dense system, including mechanism, structural and operating parameters, particle circulation prediction, gas-solid flow simulation, and potential applications, while identifying existing controversies and unresolved issues.
Article
Engineering, Chemical
Ri Zhang, Shasha Zhang, Mengyan Ding
Summary: A thin liquid film method is proposed to evaluate sand erosion in annular flow. This method considers the direct interaction between the liquid film and gas core, as well as the entrainment and deposition of droplets. The erosion rate is calculated by considering the effects of liquid entrainment and particle velocity decay. The method is fully verified by comparing with experimental data.
Article
Engineering, Chemical
Yu Suo, Xianheng Su, Wenyuan He, Xiaofei Fu, Zhejun Pan
Summary: This research investigates the mechanical properties of sandstone-shale composite through orthogonal experimental method and discrete element simulation. The results show that different lithologies and thickness ratios can affect the strength and fracture mode of the composite rock samples.
Article
Engineering, Chemical
Maurizio Troiano, Andrea El Hassanin, Roberto Solimene, Alessia Teresa Silvestri, Fabrizio Scala, Antonino Squillace, Piero Salatino
Summary: This study investigates the potential of Fluidized Bed Finishing (FBF) for square flat AlSi10Mg specimens manufactured via Laser-Powder Bed Fusion (L-PBF) additive manufacturing technology. The results show that good finishing can be achieved using rotation-assisted tests, with a maximum reduction of surface roughness by 67%. Steel particles are found to be the most effective bed material.
Review
Engineering, Chemical
Ningbo Song, Wanzhong Yin, Jin Yao
Summary: Seawater's dissolved salts and minerals have various effects on the flotation process, including influencing the characteristics and behavior of flotation factors, as well as affecting the surface of sulfide minerals. In most cases, seawater has adverse effects on the flotation of sulfide minerals, but these effects can be mitigated by adjusting the reagents.
Article
Engineering, Chemical
Kaiqiao Wu, Shuxian Jiang, Victor Francia, Marc-Olivier Coppens
Summary: In rectangular and cylindrical annular fluidized beds, pulsating gas flow can create regular bubble patterns, overcoming challenges seen in conventional units. This study provides new opportunities for modularization of fluidized bed operations.
Article
Engineering, Chemical
Shuo Li, Huili Zhang, Jan Baeyens, Miao Yang, Zehao Li, Yimin Deng
Summary: The paper assesses the behavior of cohesive Geldart C-type particles when fluidized by air with the aid of vibration. It determines that mechanical vibration is a simple and effective method to improve the fluidity of cohesive particles during fluidization.
Article
Engineering, Chemical
Zhenfei Feng, Qingyuan Zhang, Shanpan Liang, Zhenzhou Li, Fangwen Guo, Jinxin Zhang, Ding Yuan
Summary: A new micro/mini-channel heat sink (MCHS) with a combined structure of longitudinal and transverse vortex generators is designed, using Al2O3 nanofluid as the working medium. The study explores the effects of transverse vortex generator shape and longitudinal vortex generator angle on the hydraulic and thermal characteristics, comprehensive performance, entropy generation, and exergy efficiency. The results show that the triangular transverse vortex generator improves the comprehensive performance and exergy efficiency. Combined with the longitudinal vortex generator, the MCHS achieves the best comprehensive performance, entropy generation, and exergy efficiency when the Reynolds number is 742.
Article
Engineering, Chemical
Kostas Giannis, Christoph Thon, Guoqing Yang, Arno Kwade, Carsten Schilde
Summary: This study presents a 3D convolutional neural network (3D-CNN) methodology for generating realistic 3D models of particles. The method trains on 2D projections of particle images to predict their 3D shapes, and evaluates the accuracy of the predictions using Fourier shape descriptors (FSDs). This methodology has wide applications in particle shape analysis.
Article
Engineering, Chemical
Zheng-qing Zhou, Lu-jia Chai, Yu-long Zhang, Ya-bin Wang, Ze-chen Du, Tian-yi Wang, Yu-zhe Liu
Summary: The dynamic oxidation and shell-breaking processes of aluminum nanoparticles (ANPs) during heating were studied using in situ transmission electron microscopy. The results revealed that the changes in shell thickness can be divided into three stages, and the active aluminum content of ANP decreased before shell-breaking.
Article
Engineering, Chemical
Fulei Chen, Huaqing Ma, Zihan Liu, Lianyong Zhou, Yongzhi Zhao
Summary: A particle breakage model based on the particle replacement scheme, using the polyhedral model to describe particles, is proposed in this work to accurately describe the breakage of a large number of particles. Additionally, a fast-cutting algorithm is proposed to reproduce the size distribution of progeny particles determined by the breakage model. The validation and simulation results show satisfactory accuracy, efficiency, and stability of the algorithm.
Review
Engineering, Chemical
Matteo Errigo, Christopher Windows-Yule, Massimiliano Materazzi, Dominik Werner, Paola Lettieri
Summary: Gas-solid fluidized-bed systems have advantages in terms of chemical reaction efficiency and temperature control, making them widely used in industrial applications. However, the design, scale-up, and optimization of these complex units are limited by the lack of deep physical understanding. Non-invasive and non-intrusive diagnostic techniques provide a way for researchers to study these systems without affecting the flow field or directly contacting the medium under study.
Article
Engineering, Chemical
Saeed Fateh, Mohammad Behshad Shafii, Mohammad Najafi, Cyrus Aghanajafi
Summary: Applying a magnetic field to ferrofluids alters their flow characteristics and enhances heat transfer. Through visualization and quantitative investigation, it is found that the magnetic field influences the flow patterns and velocity profiles, improving fluid mixing and vorticity magnitude.
Article
Engineering, Chemical
Lei Gao, Bingbing Wei, Xiaochuan Hu, Zaifeng Yao, Yiwen Fang, Xuejian Gao
Summary: In this study, a numerical model of sand triaxial test was established using discrete element software PFC3D, and an indoor triaxial test was conducted to calibrate the numerical model. The influence of microscopic parameters on the macroscopic mechanical response of sand was analyzed. The results showed that the friction coefficient had the greatest impact on the peak strength and residual strength of the sand's stress-strain curve, and it was positively correlated. The normal tangential stiffness ratio was negatively correlated, while the porosity and boundary flexibility stiffness had minimal influence on it.
Article
Engineering, Chemical
Xuan Liu, Jie Gong, Kai Jiang, Xiaojuan Lai, Yu Tian, Kang Zhang
Summary: This study aimed to improve the performance of lignite coal water slurries (CWSs) by synthesizing a series of three-arm amphiphilic block copolymers. By controlling the relative molecular weight, hydrophilic/hydrophobic ratio, and ionic group content, the apparent viscosity of CWSs was significantly reduced and the static stability was improved. Thermogravimetric testing and XPS analysis were conducted to reveal the mechanism behind the improved performance.
Article
Engineering, Chemical
Lanka Dinushke Weerasiri, Daniel Fabijanic, Subrat Das
Summary: Fluidization at low pressure offers significant benefits for the fine chemical industry. This study investigates the behavior of bubbles and bed expansion under low pressure conditions. It is found that lower pressure leads to larger bubbles, increased bubble quantity, and higher aspect ratio. The predictability is affected by the inhomogeneous fluidization, but low pressure fluidization can generate similar bubble sizes with lower fluidizing mass compared to atmospheric pressure.