Article
Energy & Fuels
Ling Zhou, Wanning Lv, Ling Bai, Yong Han, Jian Wang, Weidong Shi, Gaoyang Huang
Summary: This paper investigates the impact of particle diameter on the gas-solid two-phase flow process in a fluidized bed using numerical simulation and experimental validation. The results show that as the particle diameter increases, the maximum bed height gradually decreases and two typical C-shaped bubbles are observed, which enhances mixing uniformity. The findings provide valuable reference for optimal design of fluidized beds, particularly for biomass or chemical looping combustion applications with coarse particles.
Article
Engineering, Chemical
Bing Liu, Kun Dong, Ru-Jia Chen, Song-Tao Chang, Guang-Wen Chu, Liang-Liang Zhang, Hai-Kui Zou, Bao-Chang Sun
Summary: This study investigates the solid-liquid mass-transfer performance of suspension in a rotating packed bed (RPB) and develops a calculation model for the mass-transfer coefficient. The effects of various operating conditions on the RPB are examined, including dispersion time, rotating speed, mesh packing thickness, liquid volume flow rate, and solid loading. The results show that the increase in rotating speed and mesh packing thickness leads to an increase in the mass-transfer coefficient. However, the solid loading has little influence. A nondimensional equation for the Sherwood number is established and the predicted values agree well with experimental values.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Engineering, Chemical
Hao Zhang, Wanbing Qiao, Xizhong An, Xinglian Ye, Jiang Chen
Summary: This study investigates the fluidization characteristics of a gas-solid fluidized bed reactor containing ternary particles using coupled computational fluid dynamics and discrete element method simulations. The results show that increasing the superficial gas velocity can enhance the overall mixing degree and mitigate the discrepancy caused by particle shape.
Article
Engineering, Chemical
Mahsa Taghavi, Brian J. Motil, Henry Nahra, Vemuri Balakotaiah
Summary: Modifications were made to the PBRE to eliminate pressure oscillations, and the effects of bed history, pre-flow conditions, flow rates, and particle diameter on gas hold-up and pressure gradients were investigated.
Article
Engineering, Chemical
Yan Zhang, Wanlong Ren, Peng Li, Xuhui Zhang, Xiaobing Lu
Summary: This paper presents a numerical simulation study on dense particulate flows with coarse particles in an inclined pipe using computational fluid dynamics-discrete element method. Different flow regimes and their transitions are identified and described. The influence of Stokes number St, Froude number Fr, inclination angle fl, etc., on critical flow regimes is analyzed, and a new diagram for recognizing regime transition is given. Two dimensionless numbers, collision stress and fluid-particle interaction stress, are defined to explain the regime transition mechanism.
Article
Mechanics
Qiang He, Weifeng Huang, Yuan Yin, Yang Hu, Yanwen Li, Decai Li
Summary: In this paper, an improved lattice Boltzmann model for fluid-fluid-solid (FFS) flows with high viscosity ratio is presented. The model combines the bounce-back particle model with the Shan-Chen multicomponent model and extends the bounce-back scheme to moving particles within the multicomponent model framework. An improved virtual solid density model is employed for wetting boundary conditions. The model is able to simulate FFS flows with high viscosity ratio and preserve the total mass of the two fluids.
Article
Engineering, Chemical
Qingshuo Wan, Zhifeng Zhao, Ruojin Wang, Meng Tang, Dewu Wang, Shaofeng Zhang, Baisong Hu
Summary: This study presents the calculation equations of pressure drop and solid flow rate in an intermittent countercurrent moving bed with multiple optimized structures. The flow fields were investigated experimentally under different conditions. It was found that the flow field in the bed is little affected by the ratio of position of the gas distributor to the bed width when it is greater than or equal to 1.0. The flow patterns were classified into continuous discharging, intermittent discharging (synchronous, asynchronous), and particle bridging. The study also established calculation formulas for the solid flow rate and pressure drop and proposed an iterative algorithm to enhance the computation accuracy.
Article
Engineering, Chemical
Chao Wang, Yao Yang, Zhengliang Huang, Jingyuan Sun, Zuwei Liao, Jingdai Wang, Yongrong Yang, Bing Du
Summary: The study found that as particle velocity increased, flow channels became more pronounced with transitions between different initial flow regimes occurring at moderate-to-high particle velocities. The flow regime map of the three-phase moving bed showed an increase in trickle flow region and a decrease in bubble flow region, making it suitable for reactions requiring operation in pulse flow, bubble flow, and transition zones.
Article
Energy & Fuels
Xiaoyu Fan, Wei Ji, Junxian Li, Zhaozhao Gao, Liubiao Chen, Junjie Wang
Summary: Liquid air energy storage (LAES) is a promising solution for large-scale energy storage that effectively integrates renewable energy sources. However, current cold energy storage (CES) methods have drawbacks and previous research often neglects the actual heat transfer processes. In this innovative study, a gravity-driven moving packed bed (MPB) based LAES system is proposed, and a thermodynamic model and heat transfer model are developed. Experimental validation of the models demonstrates the asymmetry and cold energy transfer mechanism within the CES unit. Through parameter analysis and optimization, an impressive round-trip efficiency of 57.0% is achieved, marking a significant breakthrough.
Article
Engineering, Chemical
M. J. A. de Munck, E. A. J. F. Peters, J. A. M. Kuipers
Summary: Computational Fluid Dynamics - Discrete Element Method (CFD-DEM) is widely used for heat transfer modeling in gas-solid fluidized beds. This study introduces a technique of coarse-grained CFD-DEM to overcome computational limitations and simulate larger fluidized beds. A scaling law commonly used for coarse-graining hydrodynamics is generalized to gas-solid heat transfer. The approach is successfully tested for different gas velocities, providing accurate predictions of particle temperatures and Nusselt numbers.
CHEMICAL ENGINEERING SCIENCE
(2023)
Article
Engineering, Chemical
Bo Zhang, Mengyao Guo, Zongsheng Sun, Enkhsaruul Byambajav, You Zhou, Junwei Guo, Pengfei Zhao, Zhenxing Zhang, Xuan Wang, Guanghui Yan
Summary: The apparent viscosity of binary particles decreases with the increase in coal powder content, and also drops by half with increase in gas speed. Adjusting gas velocity and magnetite powder content can effectively reduce the apparent viscosity and improve separation efficiency. A modified model for predicting the apparent viscosity of binary particles showed good performance with an overall standard deviation of 13.00% from experimental results.
Article
Thermodynamics
ELSaeed Saad ELSihy, Zhirong Liao, Chao Xu, Xiaoze Du
Summary: This study numerically analyzes the thermocline characteristics and discharge performance of a molten-salt packed-bed energy storage system. The results suggest that increasing inlet flow rate leads to higher discharging power and thermocline thickness, and slag pebbles are more effective than quartzite rock as a filler material for thermal energy storage.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Engineering, Environmental
Zhengliang Huang, Chao Wang, Yao Yang, Jingyuan Sun, Jingdai Wang, Yongrong Yang, Bing Du
Summary: Computational fluid dynamics simulations were used to investigate the flow behavior in a cocurrent three-phase moving bed reactor. The results showed that the gas-liquid flow affected the solid flow rate and the solid volume distribution in the wall and inlet region. Compared with trickle beds, TMBRs had lower liquid holdup and flow dead zone with increasing gas flow rate or decreasing liquid flow rate. The effect of liquid migration on the liquid distribution was weakened with increasing liquid flow rate. The gas-liquid-solid distribution advanced the understanding of flow behaviors in TMBRs and promoted reactor development.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Environmental
Chao Wang, Yao Yang, Zhengliang Huang, Jingyuan Sun, Jingdai Wang, Yongrong Yang, Bing Du
Summary: The study found that the effects of gas velocity and liquid velocity on gas-liquid mass transfer in a three-phase moving bed were similar to those in a trickle bed. As particle velocity increased, the liquid-phase volumetric mass-transfer coefficient first increased and then decreased. The sensitivity analysis revealed that liquid velocity had a greater impact on gas-liquid mass transfer than gas velocity and particle velocity.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Engineering, Environmental
Chanjuan Liu, Zhen Long, Yong He, Xuebing Zhou, Deqing Liang
Summary: This study investigates the growth and storage performance of CO2 hydrates under different conditions, and finds that the water film on silica gel particles is the main factor affecting gas storage efficiency. Silica gels with 30% water saturation can achieve the highest CO2 storage capacity. In addition, it is found that SDS can increase the CO2 storage volume ratio under high water saturation and reduce the volume ratio decay in repeated tests.
CHEMICAL ENGINEERING JOURNAL
(2022)
