Dynamical and thermal property of rising bubbles in the bubbling fluidized biomass gasifier with wide particle size distribution

Yang, Shiliang; Zhou, Tao; Wei, Yonggang; Hu, Jianhang; Wang, Hua

doi:10.1016/j.apenergy.2019.114178

Cited by 33 publications

(6 citation statements)

References 51 publications

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“…Yehia et al 331 revealed that the yield of H 2 and CO 2 reduced with the rising of gas inlet velocity accompanied by a decreased residence time. Yang et al 63 revealed that the particle size distribution has a large impact on the bubble dynamic and morphology. Furthermore, the large bubbles have a high fraction of H 2 , CH 4 , and CO. Hwang et al 332 found that the fluidization number (superficial gas velocity/minimum fluidization velocity) of 3.56 and the equivalence ratio (actual air-fuel ratio/stoichiometric air-fuel ratio) of 0.3 are optimal for better yield of products.…”

Section: Drying In Thermochemical Converting Reactormentioning

confidence: 99%

“…The multiphase particle-in-cell (MP-PIC) model is an effective Eulerian− Lagrangian approach employed for phase change flow in particles, such as thermochemical converting reactors. 63 In this model, the Navier−Stokes equation is utilized to calculate the continuous phase field, while Newton's law is used to track the trajectory of particles, which are initially grouped in numerical parcels (each containing multiple particles). As a result, the number of parcels that need to be calculated in the MP-PIC model is significantly reduced compared to the actual number of particles.…”

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confidence: 99%

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Recent Advances in CFD Simulations of Multiphase Flow Processes with Phase Change

Zhu

Zhang

et al. 2023

Ind. Eng. Chem. Res.

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Phase change is a phenomenon that has been extensively utilized in chemical engineering, energy, electronics, vehicle, and space exploration. From both the science and engineering perspectives, gaining a profound understanding of the intricacies of multiphase flow processes accompanied by heat and mass transfer due to phase change is of fundamental importance. Indeed, the computational fluid dynamics (CFD) has been increasingly applied as an effective tool to give an in-depth and efficient analysis of the phase change processes, thereby enhancing our understanding and capacity to control and optimize the phase change effects in these processes. This paper seeks to provide a comprehensive review of the utilization of CFD methodologies in the simulations of phase change flows across various applications, including temperature management, drying, separation and purification, and others. First, the CFD models at various scales that are developed to elucidate the phase change processes are summarized. Second, the noteworthy advances in the recent CFD simulation work on various phase change processes are presented, respectively. Finally, the challenges and potential prospects to facilitate the application of the phase change flow are discussed. The current review aims to offer insightful guidance for the CFD modeling of phase change processes in numerous engineering application scenarios.

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Section: Drying In Thermochemical Converting Reactormentioning

confidence: 99%

mentioning

confidence: 99%

Recent Advances in CFD Simulations of Multiphase Flow Processes with Phase Change

Zhu

Zhang

et al. 2023

Ind. Eng. Chem. Res.

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“…Hence, the complexities arising in such gasification reactors cannot be predicted based on the information obtained from fluidized beds with one type of particle. 14 On the impact of the particle size distribution (PSD), Yang et al 15 studied the dynamics and thermal properties of bubbles in a BFB, reporting that an increase in PSD leads to an increase in the bubble volume, aspect ratio, and mass fraction of combustible gases in the bed. In addition, the temperature and thermal conductivity of bubbles increase with the rising velocity, pressure, and density decrease.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Bubble Properties in a Bubbling Fluidized-Bed Gasification Reactor Using a Computational Particle Fluid Dynamic Model

Jaiswal

Agu

Nielsen

et al. 2023

Ind. Eng. Chem. Res.

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The conversion efficiency, operation, and design of bubbling fluidized bed (BFB) reactors depend on the bed dynamics behavior, which is significantly influenced by the bubble properties. To establish the best operating condition for efficient conversion, this study investigates the dynamics behavior of a BFB reactor using experimental measurements and computational particle-fluid dynamics simulation. The simulations account for particle size distribution and variation of particle properties used in the experiments to eliminate the possible effects on the bed behavior. Compared with a cold bed of similar biomass load and gas velocity, the results show that bubbles propagate with a wider distribution, a smaller size, and a higher frequency in the hot gasifying bed. The bubble diameter and amount of unconverted char particles increase with increasing air flow rate at a constant air−fuel ratio. Although the solid particle distribution over the bed can be uniform with increasing air flow rate, the temperature and gas species distributions lack uniformity due to different degrees of reactions across the bed. An increase in the air flow rate also results in a decrease in the gas residence time, thereby lowering the biomass conversion efficiency in the bed. At the optimum gas residence time, the concentration of hydrogen is maximum, while the concentrations of carbon dioxide and water vapor are minimum in the product gas. For efficient biomass gasification in a bubbling bed, the superficial gas velocity, u 0 , and average bubble diameter, D b , over the bed are related by gD b /u 0 = 3.0, where g = 9.81 m/s 2 is the gravity constant. This proposed model can therefore be used to size BFB reactors or set the operating gas velocity to achieve optimum gasification.

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“…Because of complex gas–solid dynamics and chemical reactions involved in the rotary drum, which are difficult to be captured by measurement tools, numerical simulation has become a powerful tool to supplement more details inside the reactor. A wide range of numerical models have been proposed, among which computational fluid dynamic (CFD) models can predict both the multiphase flow dynamics and chemical reactions, which are helpful for profoundly understanding the particle motion as well the conversion mechanism. , …”

Section: Introductionmentioning

confidence: 99%

“…A wide range of numerical models have been proposed, 7 among which computational fluid dynamic (CFD) models can predict both the multiphase flow dynamics and chemical reactions, which are helpful for profoundly understanding the particle motion as well the conversion mechanism. 8,9 With regard to the CFD investigation of biomass conversion, considerable progress has been made in multiphase flow models, such as the multifluid model (MFM), 10 the multiphase particlein-cell model (MP-PIC), 11 and the CFD coupled with discrete element model (CFD-DEM). 12 In general, MFM treats both gas and solid phases as continua, so information of individual particles is omitted.…”

Section: Introductionmentioning

confidence: 99%

Simulation of Biomass Pyrolysis in a Rotary Drum by Coupling CFD-DEM with a One-Dimensional Thermally Thick Model

Wang

Yang

2022

Energy Fuels

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A reactive computational fluid dynamic-discrete element model (CFD-DEM) is coupled with a one-dimensional thermally thick model to simulate biomass pyrolysis in a three-dimensional rotary drum reactor. Furthermore, a diffusion-based voidage algorithm and a competitive pyrolysis scheme are also implemented. After validation, the integrated model is applied to explore the effects of the drum rotating speed and the filling level. The particle distribution and motion, heat transfer, and conversion behavior are selected as indicators. Results show that the particle inventory within the central transverse section is affected by both the mechanic effect of rotation and the axial conveying due to the product gas flux. The angle of repose for the central section first increases and then decreases with rotating speed, while increasing the filling level reduces the angle of repose and delays the bed sinking. Moreover, the particles at the bed surface are energetic and thus the area of high-value granular temperature is distributed along the bed surface. The particle accumulated displacement increases and the particle residence time at the wall reduces with the rotating speed and the filling level. In addition, the specific heat conduction rate can be promoted by decreasing the rotating speed and the filling level. A higher rotating speed or a lower filling level is favorable for particle mixing and thus makes particles heat up uniformly. Finally, a higher rotating speed or filling level exerts a negative impact on biomass conversion. These findings are helpful for better understanding biomass pyrolysis in a rotary drum reactor.

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Dynamical and thermal property of rising bubbles in the bubbling fluidized biomass gasifier with wide particle size distribution

Cited by 33 publications

References 51 publications

Recent Advances in CFD Simulations of Multiphase Flow Processes with Phase Change

Recent Advances in CFD Simulations of Multiphase Flow Processes with Phase Change

Investigation of Bubble Properties in a Bubbling Fluidized-Bed Gasification Reactor Using a Computational Particle Fluid Dynamic Model

Simulation of Biomass Pyrolysis in a Rotary Drum by Coupling CFD-DEM with a One-Dimensional Thermally Thick Model

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