Article
Engineering, Environmental
V. L. Kuznetsov, S. I. Moseenkov, A. V. Zavorin, G. V. Golubtsov, V. V. Goidin, O. S. Rabinovich, A. I. Malinouski, M. Yu. Liakh
Summary: The problem of the loss of homogeneous fluidization and the formation of large clumps of MWCNTs during their catalytic synthesis in a fluidized bed reactor has been studied experimentally and theoretically. The study found that high-performance catalysts with the ability to produce agglomerates of MWCNTs with high cohesion, together with a high concentration of catalyst particles in the fluidized bed volume, play a crucial role in the formation of large clumps of MWCNTs. A relationship between the chemical components of the catalyst and the cohesive properties of the MWCNT agglomerates formed on it has been established. An approximate semi-analytical scheme for calculating the formation and growth of large fractal agglomerates (clumps) of MWCNTs during their catalytic synthesis in a fluidized bed has been developed.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Engineering, Chemical
Davin Tang, Cedric Briens, Jennifer Mcmillan
Summary: This study focuses on using low-velocity (10-30 m/s) horizontal gas jets to break agglomerates in a fluidized bed. The shear from the expanding jet cavity helps break agglomerates. Increasing the jet nozzle flowrate or the flow of gas bubbles into the jet cavity enhances agglomerate breakage.
Article
Engineering, Chemical
Jingwei Geng, Zhuo Yang, Yujie Tian, Bona Lu, Wei Wang
Summary: To investigate the effects of macroscale constraints on fluidization, fine-grid simulations were used to compare the periodic domain and realistic bed. The differences were highlighted by examining force balance conditions in the gas-phase, solid-phase, and mixture. The influence of the bounding wall was implicitly included through markers such as gas-phase pressure gradient and turbulent kinetic energies.
CHEMICAL ENGINEERING SCIENCE
(2023)
Article
Engineering, Chemical
Pengfei Dong, Qiuya Tu, Haigang Wang, Zhiping Zhu
Summary: Increasing operating pressure improves particle uniformity and reduces pressure drops along the riser height in a pressurized CFB gasification system. Discrepancies between experimental and simulation results highlight the need for a more accurate drag model and improved measurement and analysis techniques.
Article
Engineering, Chemical
Huanpeng Liu, Shaowei Wang
Summary: The experimental study investigates the fluidization behaviors of SiO2 nanoparticles with high initial bed heights, showing that the minimum fluidization velocity decreases significantly with the increase of the initial bed height. Over 80% of nanoparticles are fluidized at the bottom dense region of the bed under all fluidization conditions. There is a low-frequency mass transfer between the dense and dilute regions of the bed.
Article
Engineering, Chemical
Shaowei Wang, Huanpeng Liu, Chenyu Yang, Yang Li
Summary: This paper qualitatively reveals the hierarchical solid structures and multiscale pore structures inside fluidized nanoparticle agglomerates (FNPAs) through transmission electron microscope (TEM) images, and quantitatively analyzes the micromorphology of aggregates and simple agglomerates. The pore structure of FNPAs is complex and heterogeneous, displaying multiscale features.
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
(2021)
Article
Chemistry, Multidisciplinary
Jianxiang Zheng, Jiacheng Lu, Chenmin Ma, Tai Lv, Hongbo Lu
Summary: This study analyzed the agglomeration, fragmentation, and separation process of coarse-grained pulverized coal agglomerates (CGPCA) using a combination of numerical simulations and actual experiments. A two-phase Eulerian-Eulerian model was constructed based on the obtained data, and the simulation results showed good agreement with the experimental results. The optimal separation efficiency was achieved at an air velocity of 1.21 m/s.
Article
Chemistry, Multidisciplinary
Jianxiang Zheng, Jiacheng Lu, Chenmin Ma, Tai Lv, Hongbo Lu
Summary: In this study, the agglomeration, fragmentation, and separation process of coarse-grained pulverized coal agglomerates (CGPCA) were investigated using numerical simulations and actual experiments. The results showed that considering the two section fractal dimension in the simulation model led to better agreement with experimental results. Furthermore, the optimal separation efficiency working condition was determined at an air velocity of 1.21 m/s.
Article
Construction & Building Technology
Dapeng Zheng, Dongmin Wang, Hongzhi Cui, Xiangsheng Chen
Summary: This study focused on enhancing the pozzolanic activity of circulating fluidized bed fly ash (CFBFA) through ultrafine grinding. The findings revealed that physical activation can improve the early hydration reaction and later strength of cement with CFBFA. The research provides insights for the stability improvement and large-scale application of CFBFA-based cement.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Engineering, Chemical
G. Strenzke, M. Janocha, A. Buck, E. Tsotsas
Summary: This work systematically investigates the structural and morphological descriptors of agglomerates produced in continuously operated fluidized bed spray agglomeration, comparing the morphology of agglomerates produced in batch and continuous operation.
Article
Thermodynamics
Victor Oliveira Ferreira, Daniel Silva Junior, Karla Raphaela Braga de Melo, Bruno Blais, Gabriela Cantarelli Lopes
Summary: The high potential of liquid fluidization in water treatment and biogas production systems has not been fully explored. In this study, an alternative method based on force balance and drag correlations was proposed to estimate bed porosity. The results showed that this method provides more accurate and reliable predictions of liquid fluidized bed expansion compared to the traditional Richardson-Zaki equation.
ENERGY CONVERSION AND MANAGEMENT
(2023)
Article
Engineering, Chemical
Zhe Lin, Chengxuan Li, Xuezhi Zhang, Haiyang Zhang
Summary: This study compared a multi-stage velocity gradient fluidized bed flocculator (MGF) with a traditional mechanical stirring flocculator (MSF). The results showed that MGF achieved higher removal efficiency and faster settling performance, reducing sedimentation time. These findings provide a theoretical foundation for the design and practical application of efficient fluidized bed flocculators.
SEPARATION AND PURIFICATION TECHNOLOGY
(2023)
Article
Mathematics, Interdisciplinary Applications
Zhenjiang Zhao, Ling Bai, Weidong Shi, Linjian Li, Mahmoud A. El-Emam, Ramesh Agarwal, Ling Zhou
Summary: This study investigates the influence of microscopic forces and energy on the macroscopic motion of particles in a dense gas-solid fluidized bed using the CFD-DEM coupling approach. Experimental validation shows that drag force is positively correlated with inlet flow rate and particle diameter, tangential contact force dominates near the inlet, fluid pressure gradient force can be neglected at certain positions, and particle energy is positively correlated with inlet flow rate and particle diameter due to bubble formation.
COMPUTATIONAL PARTICLE MECHANICS
(2023)
Article
Engineering, Environmental
Jouni Ritvanen, Yegor Chechurin, Timo Hyppanen
Summary: This study introduces a practical characterization method and modeling tool for gas-solid flows, deriving phase interaction for specific solid material and providing physical predictions for both stationary and transient gas-solid flow simulations.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Thermodynamics
Yu Huang, Zhongkai Bao, Lunbo Duan, Yuanqiang Duan
Summary: This study investigates the heat transfer characteristics of immersed horizontal tubes under high-temperature and high-pressure conditions in a pressurized fluidized bed furnace. Experimental results show improved heat transfer with increased pressure and temperature, with radiation heat transfer increasing significantly as bed temperature rises. The proposed model accurately predicts experimental data points with an absolute average deviation of 11.86%.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
