An overview of processes and considerations in the modelling of fixed-bed biomass combustion

Khodaei, Hassan; Al-Abdeli, Yasir M.; Guzzomi, Ferdinando; Yeoh, Guan Heng

doi:10.1016/j.energy.2015.05.099

Cited by 123 publications

(74 citation statements)

References 149 publications

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“…Because of the obvious nonphysical character of these results, the following explanation is advisable: in the available model of fraction formation, there are no constraints on the quantity of substances formed. As was mentioned in the work [21], the direct application of the Arrhenius-modified models leads to the similar effects. The correct analysis of physical constraints requires more strict descriptions of the laws of concentration distribution which are based not only on the values of gas temperatures and velocities.…”

Section: Application Of the Model For Distribution Of The Formed Subssupporting

confidence: 51%

“…ð11Þ differs from the model in [21] in the consideration of solid fuel porosity ε. In the equation, the changes in masses Q br correspond to the gas masses formed in the course of the solid fuel decomposition.…”

Section: Mathematical Modelmentioning

confidence: 99%

“…The authors of [21] properly note that such a method can only be applied to certain ranges of temperatures, whereas for high values (above 475K) it gives absolutely unreal estimates of the rate of solid fuel drying. It is possible to conclude that the application of Eqs.…”

Section: Pyrolysis 74mentioning

confidence: 99%

“…ð9Þ andð10) without consideration of conservation laws naturally creates conditions for such problems to arise. Also, the authors of [21] indicate that the CFD models that refer to a continuous porous medium are very attractive in terms of their possible implementation.…”

Section: Pyrolysis 74mentioning

confidence: 99%

“…Thus, a good correspondence was achieved between the calculated data and the experimentally measured process of fuel conversion. The model in [21] included the following equations:…”

Section: Pyrolysis 74mentioning

confidence: 99%

See 4 more Smart Citations

Modeling of Pyrolysis in a Stage Scheme of Low‐Grade Solid Fuel Gasification

Козлов¹,

Levin²,

Svishchev³

et al. 2017

Pyrolysis

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This paper is concerned with the development of a model of wood pyrolysis in a screw reactor as the first stage of the multistage gasification process. In terms of design, the pilot pyrolyzer represents a recuperative heat exchanger where the heat carrier is represented by a mixture of exhaust and recirculation gases. To prevent clinkering of particles and thermal inhomogeneities, screw-type transportation is used to transport fuel. In order to describe kinetics of pyrolysis and transport of volatiles within the wood particles and their transition to the gas phase, we carried out the studies using a complex of synchronous thermal analysis. The original techniques for the interpretation of measurements were developed for this complex, including the techniques for technical analysis of fuels and identification of detailed kinetics and mechanism of pyrolysis. A detailed numerical modeling of pyrolyzer was performed using the Comsol Multiphysics software, which makes it possible to optimize the design and operating parameters of the pyrolysis process in a screw reactor.

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Section: Application Of the Model For Distribution Of The Formed Subssupporting

confidence: 51%

Section: Mathematical Modelmentioning

confidence: 99%

Section: Pyrolysis 74mentioning

confidence: 99%

Section: Pyrolysis 74mentioning

confidence: 99%

“…Thus, a good correspondence was achieved between the calculated data and the experimentally measured process of fuel conversion. The model in [21] included the following equations:…”

Section: Pyrolysis 74mentioning

confidence: 99%

See 3 more Smart Citations

Modeling of Pyrolysis in a Stage Scheme of Low‐Grade Solid Fuel Gasification

Козлов¹,

Levin²,

Svishchev³

et al. 2017

Pyrolysis

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Conversion of biomass to biofuels and life cycle assessment: a review

et al. 2021

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The global energy demand is projected to rise by almost 28% by 2040 compared to current levels. Biomass is a promising energy source for producing either solid or liquid fuels. Biofuels are alternatives to fossil fuels to reduce anthropogenic greenhouse gas emissions. Nonetheless, policy decisions for biofuels should be based on evidence that biofuels are produced in a sustainable manner. To this end, life cycle assessment (LCA) provides information on environmental impacts associated with biofuel production chains. Here, we review advances in biomass conversion to biofuels and their environmental impact by life cycle assessment. Processes are gasification, combustion, pyrolysis, enzymatic hydrolysis routes and fermentation. Thermochemical processes are classified into low temperature, below 300 °C, and high temperature, higher than 300 °C, i.e. gasification, combustion and pyrolysis. Pyrolysis is promising because it operates at a relatively lower temperature of up to 500 °C, compared to gasification, which operates at 800–1300 °C. We focus on 1) the drawbacks and advantages of the thermochemical and biochemical conversion routes of biomass into various fuels and the possibility of integrating these routes for better process efficiency; 2) methodological approaches and key findings from 40 LCA studies on biomass to biofuel conversion pathways published from 2019 to 2021; and 3) bibliometric trends and knowledge gaps in biomass conversion into biofuels using thermochemical and biochemical routes. The integration of hydrothermal and biochemical routes is promising for the circular economy.

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Determining the mass-related reaction effectiveness factor of large, nonspherical fuel particles for bridging between intrinsic and apparent combustion kinetics

Szűcs

Szentannai

2019

J Therm Anal Calorim

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The utilization of challenging solid fuels in the energy industry is urged by environmental requirements. The combustion kinetics of these fuel particles differs markedly from that of pulverized coal, mainly because of their larger sizes, irregular (nonspherical) shapes, and versatile internal pore structures. Although the intrinsic reaction kinetic measurements on very small amounts of finely ground samples of these particles are mostly available, a bridge toward their apparent reaction modeling is not evident. In this study, a method is introduced to build this bridge, the goodness of which was proved on the example of an industrially relevant biofuel. To do this, the results of a macroscopic combustion measurement with real samples in a well-modelable environment have to be used, and for considering some not negligible effects, 3D CFD modeling of the experimental environment is also to be applied. The outcome is the mass-related reaction effectiveness factor as a function of the rate of conversion. This variable can be considered as the active fraction of the entire particle mass on its periphery, and it can be used as the crucial element in modeling the combustion process of the same particle under other circumstances by including the actual boundary conditions. Another advantage of this method is its covering inherently the entire combustion process (water and volatile release, and char combustion) and also its applicability for reactors utilizing bigger particles like fluidized bed combustors.

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An overview of processes and considerations in the modelling of fixed-bed biomass combustion

Cited by 123 publications

References 149 publications

Modeling of Pyrolysis in a Stage Scheme of Low‐Grade Solid Fuel Gasification

Modeling of Pyrolysis in a Stage Scheme of Low‐Grade Solid Fuel Gasification

Conversion of biomass to biofuels and life cycle assessment: a review

Determining the mass-related reaction effectiveness factor of large, nonspherical fuel particles for bridging between intrinsic and apparent combustion kinetics

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