Modeling of the axial distributions of volatile species in a circulating fluidized bed boiler

Ke, Xiwei; Engblom, Markus; Zhang, Man; Silva, Paulo Santochi Pereira da; Hupa, Leena; Lyu, Junfu; Yang, Hairui; Wei, Guohua

doi:10.1016/j.ces.2021.116436

Cited by 10 publications

(9 citation statements)

References 64 publications

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“…The axial distribution of particles is an essential measure of fluidization hydrodynamics within the fluidized bed pyrolyzer 48–50 . Figure 8 reveals that the axial distribution of sand particles remains relatively unchanged as the temperature increases.…”

Section: Resultsmentioning

confidence: 99%

“…The axial distribution of particles is an essential measure of fluidization hydrodynamics within the fluidized bed pyrolyzer. [48][49][50] Figure 8 reveals that the axial distribution of sand particles remains relatively unchanged as the temperature increases. However, the peak of the axial distribution of biomass particles shifts towards the upper part of the reactor, transitioning from 0.08 to 0.2 m. This behavior can be attributed to the higher gas velocity associated with increasing temperature.…”

Section: Axial Distribution and Lacey Mixing Indexmentioning

confidence: 98%

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Coupling coarse‐grained DEM‐CFD and intraparticle model for biomass fast pyrolysis simulation and experiment validation

Wang,

Dai,

et al. 2024

AIChE Journal

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The understanding of complex fluidization hydrodynamics and chemical reactions in biomass fast pyrolysis fluidized bed reactors is lacking and requires further investigation. It is urgent to develop accurate mathematical models capable of describing the complex multiphase reaction system of biomass pyrolysis. A comprehensive multiscale model based on coarse‐grained discrete element method (DEM)‐computational fluid dynamics (CFD) was developed in open‐source MFiX code. It incorporates detailed biomass pyrolysis kinetics and an intraparticle model. To validate the model, measurements were conducted in a fluidized bed pyrolyzer, including quantifying the segmental pressure drop along the height of the bed and determining the yields and compositions of gas, liquid, and solid products. The particle mixing and segregation, axial distribution and residence time, Lacey index, and pyrolysis products were investigated. The study provides experimental and theoretical foundations for designing multiphase fluidized bed reactors and advancing biomass thermochemical conversion.

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Section: Resultsmentioning

confidence: 99%

Section: Axial Distribution and Lacey Mixing Indexmentioning

confidence: 98%

Coupling coarse‐grained DEM‐CFD and intraparticle model for biomass fast pyrolysis simulation and experiment validation

Wang,

Dai,

et al. 2024

AIChE Journal

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“…Several sub-models have been introduced in previous studies [57,58], involving material balance, coal devolatilization, char combustion, lime sulphation, etc. However, some significant modifications should be made to integrate them into the CFB combustion model of this work.…”

Section: Operating Parameters (And Steam)mentioning

confidence: 99%

“…All particles in each cell (i), involving ash, lime, fuel, and char, are specified with size (j) and residence time (k) [57]. The mass balance of each category of solids is expressed as:…”

Section: Hydrodynamics and Materials Balance (1-d)mentioning

confidence: 99%

Prediction and minimization of NOx emission in a circulating fluidized bed combustor: A comprehensive mathematical model for CFB combustion

Engblom

Yang

et al. 2022

Fuel

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“…Regarding the dynamic models of the fluidized bed, the majority of those available in the literature focus on the bubbling fluidized bed (BFB) and circulating fluidized bed (CFB). Most 1D models discretize the space by dividing the fluidized beds into several control volumes vertically and simulate based on the conservation of mass and energy to obtain the operating characteristics of the fluidized beds. − Suárez-Almeida et al presented a dynamic model of a bubbling fluidized bed gasifier to study the dynamic behavior. The results showed that the optimal start-up procedure always exists for a given operating condition, leading to the shortest start-up time and the lowest peak temperature.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Production by Coal Gasification in a Supercritical Water Fluidized Bed: Dynamic Modeling of an Industrial-Scale Reactor

2022

Ind. Eng. Chem. Res.

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This work presents two dynamic models of the supercritical water fluidized bed (SCWFB). One is a one-dimensional (1D) model that only considers the upward flow of solid and fluid phases, and the other is a 1.5-dimensional (1.5D) model that uses “core-annular” construction. The two models are compared to obtain the differences. The error in the hydrogen molar fraction reproduced by the 1.5D model is 5.48%, which is lower than that of the 1D model. The bed temperature and hydrogen yield of the 1.5D model stabilized faster and reached higher steady-state values because of the particle backmixing. The effect of coal-to-water ratios, supercritical water temperature, and boundary conditions on gasification are studied based on the 1.5D model. The results show that high water-to-coal ratio and supercritical water temperature cause high bed temperature and shorten the stabilization time. The stabilization time of the bed temperature is 20 min when the jacket water flow rate is 80 kg/min, and the stabilized bed temperature is 690.9 °C, which is similar to those at a wall temperature of 500 °C. The dynamic characteristics of the reactor are important for the design, operation, and control in an industrial-scale system for supercritical water gasification of coal.

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Modeling of the axial distributions of volatile species in a circulating fluidized bed boiler

Cited by 10 publications

References 64 publications

Coupling coarse‐grained DEM‐CFD and intraparticle model for biomass fast pyrolysis simulation and experiment validation

Coupling coarse‐grained DEM‐CFD and intraparticle model for biomass fast pyrolysis simulation and experiment validation

Prediction and minimization of NOx emission in a circulating fluidized bed combustor: A comprehensive mathematical model for CFB combustion

Hydrogen Production by Coal Gasification in a Supercritical Water Fluidized Bed: Dynamic Modeling of an Industrial-Scale Reactor

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