The influence of size and morphology on devolatilization of biomass particles

Leth-Espensen, Anna; Li, Tian; Glarborg, Peter; Løvås, Terese; Jensen, Peter Arendt

doi:10.1016/j.fuel.2019.116755

Cited by 17 publications

(14 citation statements)

References 38 publications

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“…For large particles, the accuracy of the shrinking sphere model is reduced during gasification. Anna et al 45 pointed out that the shrinking cylinder model is more suitable for particles with particle size greater than 3 mm, and the shrinking sphere model is more suitable for particles with small particle size. The establishment of the kinetic model function assumes that in a heterogeneous reaction system, there is a reactive zone at the interface of the gas‐solid two‐phase reactants, and the reaction process is characterized by the advancing process of this interface.…”

Section: Resultsmentioning

confidence: 99%

Study on the steam gasification reaction of biomass char under the synergistic effect of Ca‐Fe : Analysis of kinetic characteristics

Pang

Chen

et al. 2021

Int J Energy Res

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Biomass char gasification is an important part of biomass conversion technology; the addition of additives can effectively change the gasification reaction rate of char. The kinetic characteristics of steam gasification reaction of biomass char particles were explored by adding CaO, Fe 2 O 3 , and CaFe mixed catalyst to biomass, and the apparent activation energy and pre-exponential factors of char particles were obtained. Experimental results show that the kinetic reaction process of char steam gasification follows the shrinking cylinder model. Through linear fitting, it can be obtained that there is a good linear correlation between activation energy and pre-exponential factor, which follows the dynamic compensation effect. Under the same temperature conditions, CaO can accelerate the reaction rate of char, while Fe 2 O 3 can delay the gasification rate of char particles because of sintering phenomenon at high temperature. The synergistic effect of CaFe can reduce the total activation energy of the reaction. The addition of CaO can greatly change the kinetic performance of the Fe 2 O 3 catalyst, inhibit the sintering deactivation reaction of Fe 2 O 3 at high temperature, increase the diffusion path of steam, and promote the char steam gasification reaction.

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Section: Resultsmentioning

confidence: 99%

Study on the steam gasification reaction of biomass char under the synergistic effect of Ca‐Fe : Analysis of kinetic characteristics

Pang

Chen

et al. 2021

Int J Energy Res

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“…An overview can be seen in Figure 1. In a previously published paper, a rigorous semi-2D model was developed [19]. In this paper, a 0D model is set up.…”

Section: Methods and Model Descriptionmentioning

confidence: 99%

“…The semi-two dimensional model is described in detail elsewhere [19][20][21], and only a short introduction will be given here. The model was first presented for devolatilization at medium heating rates by Thunman et al [20], and subsequently developed further by Ström and Thunman [21].…”

Section: The Semi-two Dimensional Modelmentioning

confidence: 99%

“…To compromise between the need for a simple devolatilization model and the need for describing the complicated phenomenon of biomass particle pyrolysis, this paper introduces lumped Arrhenius kinetic parameters for a single first order global pyrolysis model. The parameters of a zero dimensional, isothermal model are found by fitting to predictions of a semi-two dimensional model [19] that previously has been validated against experimental data. The comparison is done for different gas temperatures, particle sizes, particle aspect ratios, and densities.…”

Section: Introductionmentioning

confidence: 99%

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Determination of Zero Dimensional, Apparent Devolatilization Kinetics for Biomass Particles at Suspension Firing Conditions

Espekvist

Glarborg

et al. 2021

Energies

Self Cite

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As part of the strive for a carbon neutral energy production, biomass combustion has been widely implemented in retrofitted coal burners. Modeling aids substantially in prediction of biomass flame behavior and thus in boiler chamber conditions. In this work, a simple model for devolatilization of biomass at conditions relevant for suspension firing is presented. It employs Arrhenius parameters in a single first order (SFOR) devolatilization reaction, where the effects of kinetics and heat transfer limitations are lumped together. In this way, a biomass particle can be modeled as a zero dimensional, isothermal particle, facilitating computational fluid dynamic calculations of boiler chambers. The zero dimensional model includes the effects of particle aspect ratio, particle density, maximum gas temperature, and particle radius. It is developed using the multivariate data analysis method, partial least squares regression, and is validated against a more rigorous semi-2D devolatilization model. The model has the capability to predict devolatilization time for conditions in the parameter ranges; radius (39–1569 μμm), density (700–1300 kg/m3), gas temperature (1300–1900 K), aspect ratio (1.01–8). Results show that the particle radius and gas phase temperature have a large influence on the devolatilization rate, and the aspect ratio has a comparatively smaller effect, which, however, cannot be neglected. The impact of aspect ratio levels off as it increases. The model is suitable for use as stand alone or as a submodel for biomass particle devolatilization in CFD models.

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“…During an oil drilling process, complex motion of the drill string [31,32] and the settling velocity of drill cuttings in drilling fluids [33,34] have been the focus of investigations in the field of petroleum engineering. Leth-Espensen et al [35] presented a biomass devolatilization model describing both spherical and cylindrical particles for suspension firing. Duan et al [7] investigated the flow and heat transfer past a sphere, and they first proposed the appropriate drag coefficient to replace the inertia type definition proposed by Sir Isaac Newton.…”

Section: Literature Reviewmentioning

confidence: 99%

Similarities of Flow and Heat Transfer around a Circular Cylinder

Duan

2020

Symmetry

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Modeling fluid flows is a general procedure to handle engineering problems. Here we present a systematic study of the flow and heat transfer around a circular cylinder by introducing a new representative appropriate drag coefficient concept. We demonstrate that the new modified drag coefficient may be a preferable dimensionless parameter to describe more appropriately the fluid flow physical behavior. A break in symmetry in the global structure of the entire flow field increases the difficulty of predicting heat and mass transfer behavior. A general simple drag model with high accuracy is further developed over the entire range of Reynolds numbers met in practice. In addition, we observe that there may exist an inherent relation between the drag and heat and mass transfer. A simple analogy model is established to predict heat transfer behavior from the cylinder drag data. This finding provides great insight into the underlying physical mechanism.

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The influence of size and morphology on devolatilization of biomass particles

Cited by 17 publications

References 38 publications

Study on the steam gasification reaction of biomass char under the synergistic effect of Ca‐Fe : Analysis of kinetic characteristics

Study on the steam gasification reaction of biomass char under the synergistic effect of Ca‐Fe : Analysis of kinetic characteristics

Determination of Zero Dimensional, Apparent Devolatilization Kinetics for Biomass Particles at Suspension Firing Conditions

Similarities of Flow and Heat Transfer around a Circular Cylinder

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