Article
Engineering, Chemical
Jun Xie, Hao Zhang
Summary: The CFD-DEM approach coupled with thermochemical submodels is used to study the heat transfer characteristics during solid fuel combustion in a bubbling fluidized bed. The model considers particle flow behavior, gas turbulence, heat transfer between and within phases, and chemical reactions. The study verifies the model using experimental data and quantifies the contributions of different heat transfer modes at a particle scale. It also explores the formation and development of hot spots and analyzes the influence of different particle properties on heat transfer modes.
Article
Engineering, Chemical
Chaojie Li, Yuanqiang Zou, Guiyong Li, Yuanchun Lu, Weiwen Wang, Jihai Duan
Summary: A hydrodynamic model considering particle shrinkage for multi-chamber fluidized bed is developed in this study, using computational fluid dynamics coupled with discrete element method. The model is found to provide a better representation of gas-solid fluidization in multi-chamber fluidized bed compared to experimental data. Particle swarm-scale analysis reveals that pyrolysis of poplar sawdust with an average diameter of 0.75 mm can be achieved in 30 s at 550°C. Drying and dehydration, rapid pyrolysis, and slow carbonization take 1.5 s, 17.5 s, and 11 s, respectively, with drying and dehydration occurring mainly in the first chamber and slow carbonization in the third chamber. The superficial gas velocity has limited effect on semicoke distribution.
Article
Engineering, Chemical
Huaqing Ma, Zihan Liu, Lianyong Zhou, Jiahang Du, Yongzhi Zhao
Summary: In this study, the particle flow behavior in a fluidized-bed drum was simulated and experimentally investigated, and the influences of operational conditions on particle flow behavior were comprehensively explored. The results showed that operational conditions significantly affected the particle flow behavior, but increasing the gas inlet velocity could weaken the effects of other operational conditions.
Article
Chemistry, Applied
Wanqiang Wu, Lunbo Duan, Lin Li, Daoyin Liu
Summary: In this study, the movement behavior of a single char particle in a fluidized bed was investigated using a CFD-DEM framework, and the reliability of the model was validated through experiments. It was found that the movement of the char particle was influenced by various forces, such as gravity, pressure gradient force, and collision force, and the force increased exponentially along the bed height. The findings provide guidance for optimizing the design and operation parameters of fluidized bed combustors.
FUEL PROCESSING TECHNOLOGY
(2022)
Article
Engineering, Chemical
Lianyong Zhou, Huaqing Ma, Zihan Liu, Yongzhi Zhao
Summary: This study proposes a coarse-grain CFD-DEM model for nonspherical particles, with the morphology of particles characterized by the super-ellipsoid model. The effectiveness and accuracy of the model are evaluated by comparing hydrodynamic behaviors with traditional CFD-DEM. The results show that the proposed model accurately models gas-solid flow with nonspherical particles and reduces computational costs.
Article
Engineering, Chemical
Zhan Luo, Yuanhe Yue, Shuai Wang, Yansong Shen
Summary: In this study, the spout deflection behavior of cohesive particles in a pseudo-2D spout fluidized bed is investigated using computational fluid dynamics - discrete element method. It is found that cohesive particles, especially those covered with honey, exhibit smaller spout deflection compared to dry particles. Furthermore, the spout deflection angle increases with increasing spouting gas velocity for both dry and cohesive particles.
Article
Engineering, Chemical
Jun Xie, Wenqi Zhong, Yingjuan Shao
Summary: This study simulated char combustion in a three-dimensional bubbling fluidized bed using the CFD-DEM method coupled with a thermochemical submodel. The influence of particle properties on temperature, reaction rates, and the relationship between particle mixing, heat transfer, and reaction were investigated. Results showed that particle size affects the char combustion rate, while density has a slight effect. The distribution of particle temperature, CO, and CO2 concentrations is consistent with the fuel particle profile in most cases.
Article
Mechanics
Zhenjiang Zhao, Ling Zhou, Ling Bai, Mahmoud A. El-Emam, Ramesh Agarwal
Summary: The coarse-grained (CG) CFD-DEM method reduces the number of particles by replacing multiple smaller particles with larger ones called parcels, and fully considers particle collisions. The investigation shows that the CG CFD-DEM method significantly decreases computation time in simulating dense gas-solid flows, and the results agree well with experimental data and fine-grained CFD-DEM method.
Article
Chemistry, Applied
Weiwen Wang, Yuanchun Lu, Kunwen Xu, Kai Wu, Zisheng Zhang, Jihai Duan
Summary: This paper investigates the particle shrinkage characteristics of biomass particles at different temperatures, establishes a mathematical model, conducts CFD-DEM simulation to study fluidization states in a multi-chamber fluidized bed at different pyrolysis temperatures, and verifies the model with PIV experiments. The study also provides analysis on residence time distribution and axial particle size variation in each compartment.
FUEL PROCESSING TECHNOLOGY
(2021)
Article
Energy & Fuels
Dali Kong, Shuai Wang, Kun Luo, Jiahui Yu, Jianren Fan
Summary: The methanation process in a bubbling fluidized bed (BFB) reactor is studied using computational fluid dynamics-discrete element method (CFD-DEM) with thermochemical sub-models. A novel algorithm is developed for bubble identification and statistics. The effects of key operating parameters on bubble behaviors are quantified and the underlying mechanism of mesoscale bubble behaviors is elucidated. The results show that the bubble dynamics can be well captured by the algorithm and the interphase heat and mass transfer can be enhanced by adjusting the operating parameters.
Article
Computer Science, Interdisciplinary Applications
Hanqiao Che, Tang Chen
Summary: The objective of this study is to investigate the particle circulation characteristics in a tapered fluidized bed (TFB). The study explores an appropriate method to quantify particle circulation time, the effects of operational parameters on particle circulation time, and the relationship between particle mixing and particle circulation. The findings suggest that air velocity, wall inclination angle, particle size, inter-particle cohesive forces, and the open area ratio of the central region of the air distributor all have significant effects on particle circulation. The study provides valuable insights for the design, optimization, and control of processes involving TFBs.
ENGINEERING COMPUTATIONS
(2022)
Article
Energy & Fuels
Zihan Liu, Huaqing Ma, Yongzhi Zhao
Summary: The study investigates the fluidization behavior of non-spherical polyhedral particles using a numerical CFD-DEM method. The results show that the CFD-DEM model with the polyhedron approach can accurately predict the behaviors of polyhedral particles, which exhibit stronger motion and higher mixing degree compared to spherical particles under the same fluidization gas velocity.
Article
Engineering, Chemical
Zhi Han, Yingjuan Shao, Wenqi Zhong
Summary: A novel CFD-DEM particle attrition model is developed to investigate the attrition mechanism of particles in fluidized beds. The results show that the attrition process can be divided into unstable attrition stage and stable attrition stage, with the former further divided into high-speed attrition phase and low-speed attrition phase. Wear and fragmentation increase with increasing height-diameter ratio and superficial gas velocity. The wear ratio decreases with increasing particle size, while the fragmentation ratio first decreases and then increases. Particle attrition mechanism also exhibits spatial non-uniformity.
Article
Energy & Fuels
Conghui Gu, Haichao Zhao, Bingyang Xu, Junjie Yang, Jun Zhang, Mingpu Du, Yuan Liu, Dmitriy Tikhankin, Zhulin Yuan
Summary: This article investigates the distribution and agglomeration characteristics of chain-like biomass particles in a fluidized bed through the coupled model of computational fluid dynamics -discrete element method. The results show that chain-like biomass particles tend to agglomerate near the wall and corners, with a maximum volume fraction of 0.11%. The particle concentration distribution exhibits an inverted "C" shape. The gas velocity and biomass particle mass flow rate have significant effects on the distribution and agglomeration characteristics of chain-like biomass particles.
Article
Engineering, Chemical
Wanqiang Wu, Lunbo Duan, Lin Li, David Pallares
Summary: This study investigates the movement behavior of a single char particle under combustion conditions in a fluidized bed using a CFD-DEM framework. The results show that spherical char particles have more vigorous movement compared to non-spherical particles. An increase in fluidization velocity leads to a higher probability of particles populating the splash zone and also increases rotational velocity.
Article
Engineering, Chemical
Hao Wang, Shiteng Wang, Yujie Wang, Yuhang Fu, Yi Cheng
Summary: A ternary fluid color-gradient lattice Boltzmann model was proposed to study the effect of mixing-induced dynamic interfacial tension on diffusive mixing of two fluids inside moving microdroplets. Results showed that dynamic interfacial tension can lead to interface motion and solute redistribution, improving mixing efficiency. This model can be used for quantitative characterization of mixing behavior and inspire new designs for mixing intensification.
Article
Engineering, Environmental
Peng Yan, Yuxin Chen, Yi Cheng
Summary: The study utilized highly thermal conductive Foam SiC as the structured support and proposed three strategies to intensify the coating stability, achieving excellent heat transfer and meeting the industrial goal of catalytic performance. A Dual Interfaces coating stability mechanism was proposed, providing fundamental guidelines for successful development of stable coating strategies.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Chemistry, Physical
Dan Dang, Yuxin Chen, Xin Chen, Kai Feng, Binhang Yan, Yi Cheng
Summary: Introduction of TiO2 enhances catalytic performance of phase-pure M1 MoVNbTeOx catalyst in oxidative dehydrogenation of ethane, with TiO2 content showing a significant impact on ethylene productivity. The M1/TiO2 composite catalysts exhibit stable crystal structure and surface morphology, with TiO2 improving reduction/re-oxidation rate of lattice oxygen species in the catalysts, thus enhancing catalytic performance.
CATALYSIS SCIENCE & TECHNOLOGY
(2022)
Article
Chemistry, Physical
Yuxin Chen, Dan Dang, Binhang Yan, Yi Cheng
Summary: Composite catalysts of M1-TiO2 were prepared by two methods and showed improved catalytic performance in the ODHE process. The introduction of TiO2 increased the V5+ content on the catalyst surface and the reactivity of active oxygen species, contributing to the promotion of catalytic performance.
Article
Engineering, Chemical
Yuxin Chen, Shuairen Qian, Kai Feng, Yujie Wang, Binhang Yan, Yi Cheng
Summary: The phase-pure M1 MoVNbTeOx catalyst has been coated on cordierite monolith using PVP-sol binder solution. A layered M1@CeO2@Monolith structured catalyst has been prepared to enhance the catalytic performance and stability. The M1@CeO2@Monolith structured catalyst exhibits superior catalytic performance for ODHE reaction.
CHEMICAL ENGINEERING SCIENCE
(2022)
Article
Engineering, Chemical
Mehran Ali, Yi Cheng, Yue Li, Hang An, Yong Jin
Summary: This study developed a laboratory-scale plasma pyrolysis system to investigate the impacts of residual oil characteristics and operating variables on the conversion of non-conventional oil resources. The results showed that higher specific enthalpy of the residual oil led to higher yields of valuable chemicals and materials. Additionally, ethane was found to be an effective quenching medium to improve the production, while controlling the gas temperature to prevent further pyrolysis.
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
(2023)
Article
Chemistry, Physical
Peng Yan, Yi Cheng
Summary: Methane steam reforming is expected to be the dominant method for hydrogen production in the future. The use of a membrane reactor can significantly save energy and achieve process and equipment compactness, especially for decentralized applications. This study focuses on the design of a particle-based packed-bed membrane reactor and investigates its operational window and design challenges through experimental and computational approaches, with a particular emphasis on the scale of the reactor and catalyst activity. The results reveal the optimal operation conditions for maximizing hydrogen flux and identify catalyst activity as the key limiting factor for further process intensification.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Engineering, Chemical
Peng Yan, Yi Cheng
Summary: Membrane reactor is a promising method for distributed hydrogen production, but mass, heat transfer, and catalyst cost are the main challenges. In this study, Foam Structured Membrane Reactor (FSMR) using structured foam SiC was investigated. The results showed that FSMR can enhance radial heat and mass transfer, and save catalyst usage.
JOURNAL OF MEMBRANE SCIENCE
(2022)
Article
Chemistry, Physical
Shuairen Qian, Yuxin Chen, Yujie Wang, Binhang Yan, Yi Cheng
Summary: This study employed an atomic substitution strategy to investigate the active site of the M1 MoVNbTeOx catalyst for the oxidation dehydrogenation of ethane reaction and found that the synergistic interaction between Te-O and V-O sites is the intrinsic active site for the reaction.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Engineering, Chemical
Yuxin Chen, Dan Dang, Binhang Yan, Yi Cheng
Summary: This study demonstrates that adding CeO2 to MoVNbTeOx using the sol-gel method can effectively enhance its catalytic performance. The characterization results show that the improved performance is attributed to the increased active species at the catalyst surface due to the addition of CeO2. This work provides a new solution to simplify the preparation procedure of MoVNbTeOx catalysts and avoid mass loss during purification.
CHEMICAL ENGINEERING SCIENCE
(2022)
Article
Chemistry, Analytical
Zhe Fu, Fang Hua, Shiqi Yang, Hangzhou Wang, Yi Cheng
Summary: The accumulation of waste plastics is a pressing and challenging environmental problem. This study investigates the pyrolysis of polyethylene (PE) using various analytical methods, including thermogravimetric analysis (TGA) and pyrolysis/gas chromatography/mass spectrometry (PyGC-MS). The pyrolysis behavior of different types of polyethylene is compared, and it is found that the temperature in the second stage of pyrolysis has a significant impact on the yield and selectivity of light olefins.
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
(2023)
Review
Chemistry, Physical
Yuxin Chen, Binhang Yan, Yi Cheng
Summary: Ethylene is currently produced by steam cracking of naphtha or light alkanes, but this process has high energy demands, gas separation costs, and CO2 emissions. The oxidative dehydrogenation of ethane (ODHE) using MoVNbTeOx catalysts is a promising alternative due to its lower temperature operation and better economic viability. This paper provides a comprehensive review on the application of MoVNbTeOx catalysts in the ODHE process, covering their origin, catalyst treatment, material characterization, reaction mechanism, evaluation, and reactor design, contributing to the understanding and development of the ODHE process based on MoVNbTeOx catalysts.
Article
Chemistry, Physical
Yujie Wang, Shuairen Qian, Yuxin Chen, Binhang Yan, Yi Cheng
Summary: This study investigates the performance of LaNiO3 oxides prepared by the Pechini method as catalysts for the steam reforming of methane (SRM). The properties of LaNiO3 samples were found to vary with the calcination temperature, resulting in changes such as increased grain size, decreased specific surface area, higher reduction temperature, reduced Ni-0 grain size, and enhanced metal-support interaction. The highest CH4 conversion rate was achieved over LaNiO3 calcinated at 800°C. Additionally, it was found that an S/C ratio of 1.5 was optimal for CH4 conversion, and excessive metal-support interaction and unreacted steam led to a decrease in catalytic activity. Furthermore, increasing the calcination temperature was found to improve the catalyst's carbon deposition resistance, as confirmed by TPO and Raman analysis.
Article
Engineering, Chemical
Shiteng Wang, Hao Wang, Yi Cheng
Summary: Miscible reagents inside moving droplets exhibit a different mixing mechanism due to dynamic interfacial tension. However, it is difficult to measure this tension experimentally. In this study, a ternary color-gradient lattice Boltzmann model was used to investigate the effect of dynamic interfacial tension on mixing inside moving droplets. The model allows for the independent setting of diffusion coefficient and interfacial tension with high accuracy. Simulation results show that dynamic interfacial tension influences mixing by redistributing components based on their relative positions and inner swirls. Furthermore, the presence of dynamic interfacial tension significantly improves mixing performance in droplets compared to various channels, but this positive effect is reduced by wall constraints.
CHEMICAL ENGINEERING SCIENCE
(2023)
Article
Chemistry, Analytical
Fang Hua, Zhe Fu, Shiqi Yang, Hangzhou Wang, Ye Ji, Yi Cheng
Summary: Waste plastics, especially polyethylene, have become a significant global environmental issue, leading to white pollution. This study proposes a generalized molecular-level kinetic model for the pyrolysis of polyethylene, which effectively reduces the number of ordinary differential equations derived from reaction kinetics through simplified network design. The model demonstrates high generalizability and provides accurate predictions, with a mean relative error of less than 5% between experimental and model data. The comparison between polyethylene and polystyrene pyrolysis reveals different pyrolysis mechanisms based on molecular structures.
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
(2023)
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.
