CFD modeling of the flow dynamics and gasification in the combustor and gasifier of a dual fluidized bed pilot plant

Wan, Zhanghao; Yang, Shiliang; Wei, Yonggang; Hu, Jianhang; Wang, Hua

doi:10.1016/j.energy.2020.117366

Cited by 30 publications

(7 citation statements)

References 58 publications

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“…The numerical simulation has been extensively applied to visually provide detailed information on the complex process of reactions in gasifiers (Fang et al 2019;Wan et al 2020;Wang et al 2020;Yang et al 2021). However, there are relatively few studies dedicated to fly ash's gasification performance in an entrained-flow gasifier.…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of an 80,000 Nm3/h fly ash entrained-flow gasifier at various burner inclination angles

Niu

Zeng

et al. 2021

Environ Sci Pollut Res

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The raw syngas effluent from a fluidized bed gasifier typically contains a large amount of fly ash having a high concentration of carbon, which is undesirable. The present work examined the newly developed entrained-flow gasification technology intended to gasify raw syngas. Simulation of gas-solid flow and reaction behavior in an industrial-scale entrained-flow gasifier applying this new technology was first performed to obtain a better understanding of the particle flow and gasification characteristics. In addition, the devolatilization and heterogeneous reactions of fly ash particles were characterized by thermogravimetric analysis and user-defined function. The predictions from the simulation showed good agreement with the results of in situ experimental measurements. The combustion reaction for raw syngas occurred in the burner jet zone. As the hot gaseous products diffused, gasification reactions dominated the other zones. When burner inclination angle was 0°, 8.5°, and 25.5°, the temperature at the bottom outlet of the gasifier was lower than the ash flow temperature with the value of 1360 °C. Solid slag formed and blocked the outlet. By comparison, this gasifier with the burner inclination angle of 17° could discharge the liquid slag and function as a continuous operation. In this way, the carbon conversion in fly ash reached the maximum value of 87%.

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Section: Introductionmentioning

confidence: 99%

Numerical analysis of an 80,000 Nm3/h fly ash entrained-flow gasifier at various burner inclination angles

Niu

Zeng

et al. 2021

Environ Sci Pollut Res

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“…(2) Fluidized Bed Gasification Fluidized-bed gasifiers (FBGs) are more suitable for CSTGB systems than a fixed bed and entrained flow gasifiers because of their enhanced heat and mass transfer by the gasification flow fluidizing the bed material [62]. FBGs offer the enhanced interaction between the gas and solid phases leading to higher hydrogen concentrations in the gas product in Table 4 [62][63][64]. They also offer higher flexibility in terms of the selection of feedstocks [65].…”

Section: Types Of Gasification Reactorsmentioning

confidence: 99%

“…The size of biomass particles can impact thermochemical reaction processes, especially the heat transfer rate [63]. Chuaboon et al conducted experimental studies on different biomass feedstocks using a 1.5 kWth solar steam gasification device [80].…”

Section: Particle Sizementioning

confidence: 99%

Concentrated solar thermochemical gasification of biomass: Principles, applications, and development

Fang

Paul

Varjani

et al. 2021

Renewable and Sustainable Energy Reviews

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“…17 By testing various types of bed material (quartz, olivine, feldspar, limestone, and their mixtures) in a DFB steam gasification pilot plant, Mauerhofer et al 14 compared and analyzed their influences on the system performance. Recently, Wan et al 18 studied the reactive gas-solid flow dynamics in a pilot-scale DFB biomass gasifier using the multiphase particle-in-cell approach. The numerical results were then compared with the experimental data, and the effect of the heat carriers' size distribution on the bed hydrodynamics was also examined.…”

Section: Introductionmentioning

confidence: 99%

Effect of sand particle size on the hydrodynamics of a dual fluidized bed cold flow system applied for waste‐to‐energy gasifiers

Dinh

Hsiau

et al. 2022

Intl J of Energy Research

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Summary Since the dual fluidized bed (DFB) system has been increasingly adopted for waste‐to‐energy gasification, a three‐dimensional computational fluid dynamics full‐loop model of a DFB cold flow system has been developed to predict the pressure and sand circulation rate (SCR) under various operating conditions. The pressure data were recorded at 18 specified points along the system height. In addition, the SCRs were determined at the two crucial positions connecting the riser and the gasifier and vice versa. The simulation results were then validated against the experimental data, taking into account the effects of the sand particle size (ds), the air inlet velocity in the riser (v0,riser), and the initial gasifier bed height (h0,gasifier). It could be observed in the riser that the flow structures of the smaller ds(s) were almost scattering patterns, while those of the bigger ones were mainly clusters. Compared with bigger ds(s), more homogeneous pressure distributions in the riser and higher bed expansion in the gasifier were obtained with smaller ones. A compromise between the system performance and pre‐treating cost for the feedstock particle sizes should be considered further to achieve the best system performance. On the other hand, the increases of the v0,riser and the h0,gasifier enhanced the gasifier bed pressure, facilitating the downward sand flow back to the riser via the LLS. Although some minor discrepancies existed between the simulation and experimental data, the predicted tendencies agreed well with the measured ones. It was also found that a system operating with ds = 500 μm, at v0,riser = 4.0 m/s and h0,gasifier = 0.25 m yielded stable flow characteristics and optimal global SCR. Moreover, some unexpected phenomena predicted and verified with the experimental observations could be avoided or minimized using suitable particle sizes of the feedstock and operating parameters. In sum, the better validation results with lower errors than our previous study, the more reasonable air‐sand flow patterns, and the substantial predictions of undesirable problems are the significant improvements of this study, providing valuable information for effectively designing and operating the practical DFB hot flow systems. Novelty Statement This study developed a 3D computational fluid dynamics full‐loop model of a DFB cold flow system for predicting the pressure and sand circulation rates under various operating conditions of particle size, inlet velocity, and initial bed height. The better validation results against the experimental data, the more reasonable air‐sand flow patterns, and the substantial predictions of undesirable problems are the significant improvements of this study, providing helpful information for designing and operating the DFB hot flow gasifiers.

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CFD modeling of the flow dynamics and gasification in the combustor and gasifier of a dual fluidized bed pilot plant

Cited by 30 publications

References 58 publications

Numerical analysis of an 80,000 Nm3/h fly ash entrained-flow gasifier at various burner inclination angles

Numerical analysis of an 80,000 Nm3/h fly ash entrained-flow gasifier at various burner inclination angles

Concentrated solar thermochemical gasification of biomass: Principles, applications, and development

Effect of sand particle size on the hydrodynamics of a dual fluidized bed cold flow system applied for waste‐to‐energy gasifiers

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