Article
Engineering, Environmental
M. J. A. de Munck, M. Dullemond, E. A. J. F. Peters, J. A. M. Kuipers
Summary: Fluidized bed drying is a dynamic process that involves changes in bed hydrodynamics, mass and heat transfer, and segregation and mixing tendencies over time. This study used pseudo-2D fluidized bed experiments with binary and ternary solid mixtures to investigate these dynamics. The results, obtained through particle image velocimetry infrared thermography technique and machine learning algorithm, revealed significant hydrodynamic changes and various segregation and mixing tendencies due to water evaporation from the porous gamma-Al2O3 material. The competition between size and density-based segregation and mixing dynamics resulted in changing bed configurations and influenced the local drying behavior. The study also highlighted the potential benefits of drying wider size distributions for more complex and efficient process operation.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Energy & Fuels
Diana Carolina Guio-Perez, Filip Johnsson, David Pallares
Summary: This study used Magnetic Particle Tracking (MPT) to investigate solid fuel conversion in fluidized bed reactors. The results showed that increasing bed height improves solid mixing, with fluidization velocity having a higher sensitivity.
Article
Engineering, Environmental
M. J. A. de Munck, E. A. J. F. Peters, J. A. M. Kuipers
Summary: Enhancing gas-solid contacting in a fluidized bed through mechanical vibration improves solids drying characteristics. This study uses a pseudo-2D vibro-fluidized bed setup to experimentally investigate this improved drying behavior. A coupled particle image velocimetry-infrared thermography technique is employed to characterize local solids velocity and temperature fields. Results show that the added vibration significantly increases solids drying rate compared to a traditional gas-fluidized bed, primarily due to enhanced meso-scale particle agitation. Additionally, the appearance of gas bubbles and particle temperature standard deviation are highly influenced by the applied vibration amplitude and frequency.
CHEMICAL ENGINEERING JOURNAL
(2023)
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
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
Jikai Huang, Huanan Li, Chongliang Huang, Yake Jiang, Zhigang Liu
Summary: A novel method is developed to measure the micro mixing ratio of binary solids in dense fluidizations. The mixing process within a bubbling fluidized bed is resolved and dispersion co-efficient and mixing index methods are applied. The results indicate that diffusion plays a crucial role in mixing at the bottom and top of the fluidized bed, while convection is the primary mechanism of mixing at the center.
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
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
Engineering, Chemical
Ruixu Wang, Ziliang Wang, Xiaotao Bi, C. Jim Lim, Shahabaddine Sokhansanj
Summary: A prototype horizontal pulsed fluidized bed (HPFB) was constructed for continuous biomass torrefaction in this study. The solids residence time distribution (RID) of hemlock sawdust in the HPFB reactor was measured to investigate particle transport and mixing. The experimental results showed that the horizontal dispersion coefficients in the HPFB were influenced by weir height, gas pulsation frequency, solids feed rate, and gas velocity. The obtained horizontal solids dispersion coefficients in the HPFB were significantly smaller than values calculated by literature correlations.
Article
Engineering, Chemical
Chengxiu Wang, Xin Su, Mengjie Luo, Xingying Lan, Jinsen Gao, Chunming Xu, Mao Ye, Jesse Zhu
Summary: A comprehensive study on hydrodynamics was conducted in a pilot circulating fluidized bed riser with high solids flux and gas velocity. The results showed that solids holdup accounted for 20-30% of the riser with such high solids flux. As the solids flux increased to 1800 kg/m(2)s, both solids holdup and particle velocity became more uniform, indicating reduced back-mixing. Compared to the circulating turbulent fluidized bed, the riser reactor with high solids flux exhibited good gas-solids contact.
Article
Engineering, Chemical
Wenjian Cai, Shuyan Wang, Xiaoxue Jiang, Hassan Muhammad, Huilin Lu
Summary: This study simulated the mixing process of SC and LC binary mixture in a supercritical carbon dioxide fluidized bed using unequal granular temperature-based kinetic theory, and identified the mixing/segregation tendency between the two components based on synergy angle.
Article
Engineering, Chemical
Wenjian Cai, Shuyan Wang, Mustafa Ahmed Khogley Ahmed, Weiqi Chen, Huilin Lu
Summary: Numerical simulations were conducted to investigate the mixing and segregation of flotsam and jetsam components in a binary mixture in a supercritical water fluidized bed. The results indicated that increasing the temperature and fluidizing velocity of the supercritical water contributes to the mixing of the components along the bed height.
CHEMICAL ENGINEERING SCIENCE
(2021)
Article
Engineering, Chemical
Tolu Emiola-Sadiq, Jiachen Wang, Lifeng Zhang, Ajay Dalai
Summary: This study experimentally investigated the mixing and segregation of binary mixtures involving biomass materials in a fluidized bed, focusing on the axial and radial distribution of biomass particles. Results showed that increasing fluidizing velocity improved mixing extent, while the mixing index decreased beyond a certain biomass loading threshold.
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.
Article
Energy & Fuels
Antonio Soria-Verdugo, Eduardo Cano-Pleite, Alberto Passalacqua, Rodney O. Fox
Summary: The effect of biomass particle shape on the conversion of beech wood during pyrolysis in a bubbling fluidized bed was investigated. The experimental results demonstrated that the pyrolysis velocity of the particles was proportional to their characteristic heat transfer length. The pyrolysis time ranged from 43 to 85 s at 500°C and from 27 to 53 s at 600°C.
Article
Engineering, Chemical
Louise Lundberg, Placid A. Tchoffor, David Pallares, Henrik Thunman, Kent O. Davidsson
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2019)
Article
Engineering, Chemical
Jesper Aronsson, Anders Lyngfelt, David Pallares
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2019)
Article
Energy & Fuels
Anna Kohler, David Pallares, Filip Johnsson
Article
Engineering, Chemical
Guillermo Martinez Castilla, Anton Larsson, Louise Lundberg, Filip Johnsson, David Pallares
Article
Ergonomics
Sara Moll, Griselda Lopez, Alexander Rasch, Marco Dozza, Alfredo Garcia
Summary: This paper analyzes the factors influencing the duration of overtaking cyclists on two-lane rural roads in Spain. The study found that flying maneuvers are more prevalent than accelerative maneuvers, with shorter overtaking durations. Overtaking duration increases on wider roads and with larger groups of cyclists.
ACCIDENT ANALYSIS AND PREVENTION
(2021)
Article
Psychology, Applied
Alexander Rasch, Sara Moll, Griselda Lopez, Alfredo Garcia, Marco Dozza
Summary: Overtaking cyclists on rural roads poses a safety concern, as it requires drivers to handle their interaction with the cyclists and other oncoming vehicles. This study examined the perceived safety of drivers and cyclists during the overtaking maneuver and developed Bayesian ordinal logistic regression models to predict their perceived safety scores. The results showed that drivers' perceived safety decreased when there was an oncoming vehicle with a low time-to-collision, while cyclists' perceived safety was reduced by a small lateral clearance and a high overtaking speed. These findings can inform infrastructure development, policymaking, and the development of safety systems for both drivers and cyclists.
TRANSPORTATION RESEARCH PART F-TRAFFIC PSYCHOLOGY AND BEHAVIOUR
(2022)
Article
Ergonomics
Marco Dozza, Alessio Violin, Alexander Rasch
Summary: This article introduces a data-driven evaluation framework for micro-mobility vehicles, comparing bicycles and e-scooters in field tests. The preliminary results suggest that e-scooters may have advantages in maneuverability and comfort, although they require longer braking distances. The data collected from e-scooters can facilitate policy making and further research on the integration of micro-mobility vehicles.
JOURNAL OF SAFETY RESEARCH
(2022)
Article
Engineering, Civil
Alexander Rasch, Marco Dozza
Summary: This study developed a driver model based on logistic regression to improve collision warning systems by predicting driver behavior during overtaking and providing timely warnings.
IEEE TRANSACTIONS ON INTELLIGENT TRANSPORTATION SYSTEMS
(2022)
Article
Engineering, Chemical
Diana Carolina Guio-Perez, Anna Kohler, Anna Prati, David Pallares, Filip Johnsson
Summary: The aim of this study is to investigate the effects of bulk solids properties on the drag experienced by large spheres in an emulsion of group-B solids and analyze the reaction of different suspensions to applied shear rates. The results show that an increase in bulk solids size, angularity, and density leads to a decrease in the terminal velocity of the sphere. Beds of larger, more angular, or denser bulk solids exhibit lower levels of shear stress at lower shear rates.
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
(2023)
Article
Ergonomics
Marco Dozza, Tianyou Li, Lucas Billstein, Christoffer Svernlov, Alexander Rasch
Summary: This study compared the longitudinal control performance of e-scooters, Segways, and bicycles. The results showed that e-scooters and Segways have less efficient braking performance compared to bicycles. Bicycles were perceived as more stable, maneuverable, and safe. The study suggests that new micromobility solutions may require behavior and infrastructure adaptations to improve safety.
JOURNAL OF SAFETY RESEARCH
(2023)
Article
Energy & Fuels
Diana Carolina Guio-Perez, Guillermo Martinez Castilla, David Pallares, Henrik Thunman, Filip Johnsson
Summary: This paper introduces a method of electricity-charged thermochemical energy storage (TCES) using high-temperature solid cycles, which can absorb variable renewable energy (VRE) and convert it into dispatchable heat and power. Using a Swedish case study, the technical suitability of TCES-integrated district heating (DH) production is assessed and some practical implications and additional implementation options are discussed. The results show that the proposed scheme is technically feasible for the Swedish case, with an estimated process energy efficiency (electricity to heat) of 90%.
Article
Ergonomics
Oliver Lee, Alexander Rasch, Arend L. Schwab, Marco Dozza
ACCIDENT ANALYSIS AND PREVENTION
(2020)
Article
Ergonomics
Alexander Rasch, Christian-Nils Boda, Prateek Thalya, Tobias Aderum, Alessia Knauss, Marco Dozza
ACCIDENT ANALYSIS AND PREVENTION
(2020)
Article
Ergonomics
Alexander Rasch, Gabriele Panero, Christian-Nils Boda, Marco Dozza
ACCIDENT ANALYSIS AND PREVENTION
(2020)
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.