Eulerian CFD fouling model for fixed bed biomass combustion systems

Chapela, Sergio; Porteiro, Jacobo; Mı́guez, J.L.; Behrendt, Frank

doi:10.1016/j.fuel.2020.118251

Cited by 12 publications

(4 citation statements)

References 33 publications

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“…They concluded that an external heat source requires a high-temperature combustion system. In another simulation, Chapela, Porteiro [29] modeled fouling in biomass combustion systems. Biomass combustion is important to investigate how to minimize NO X and nitrous oxide emissions according to a study conducted by Ma, Khan [30].…”

Section: Introductionmentioning

confidence: 99%

CFDs Modeling and Simulation of Wheat Straw Pellet Combustion in a 10 kW Fixed-Bed Downdraft Reactor

Nath,

Chen,

Bowtell

et al. 2024

Processes

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This research paper presents a comprehensive study on the combustion of wheat straw pellets in a 10 kW fixed-bed reactor through a Computational Fluid Dynamics (CFDs) simulation and experimental validation. The developed 2D CFDs model in ANSYS meshing simulates the combustion process in ANSYS Fluent software 2021 R2. The investigation evaluates key parameters such as equivalence ratio, heating value, and temperature distribution within the reactor to enhance gas production efficiency. The simulated results, including combustion temperature and produced gases (CO2, CO, CH4), demonstrate a significant agreement with experimental combustion data. The impact of the equivalence ratio on the conversion efficiency and lower heating value (LHV) is systematically explored, revealing that an equivalence ratio of 0.35 is optimal for maximum gas production efficiency. The resulting producer gas composition at this optimum condition includes CO (~27.67%), CH4 (~3.29%), CO2 (~11.09%), H2 (~11.09%), and N2 (~51%). The findings contribute valuable insights into improving the efficiency of fixed-bed reactors, offering essential information on performance parameters for sustainable and optimized combustion.

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Section: Introductionmentioning

confidence: 99%

CFDs Modeling and Simulation of Wheat Straw Pellet Combustion in a 10 kW Fixed-Bed Downdraft Reactor

Nath,

Chen,

Bowtell

et al. 2024

Processes

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“…With the above in mind, simulations have been conducted into the fluid dynamics, heat transfer and mass transfer into packed beds and their freeboard region. [25][26][27][28] To facilitate this, Porteiro et al [29][30][31] developed various numerical models using ANSYS Fluent for fixed bed configurations. Despite this, there exists very limited literature on resolving the secondary air effects in these configurations with the realisation that these are likely to lead to complex flow features 32 even though very limited detail has been given on the boundary conditions used or the numerical approach applied.…”

Section: Introductionmentioning

confidence: 99%

Secondary air induced flow structures and mixing in a fixed bed combustor

Junejo

Chapela

Porteiro

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part A:

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Air staging features widely in biomass combustion from small space heaters to industrial-scale moving grate systems. Whilst studies have been conducted into the impact of air staging on emissions and combustion performance, there is little or no insight into the exact flow dynamic and physical mechanisms that are induced by secondary air under such conditions. This paper uses experimental data to validate numerical predictions before investigating the flow field structures and mixing characteristics in a fixed bed air staged combustor. The study utilizes Constant Temperature Anemometry (CTA) experiments to establish boundary conditions for a lab-scale fixed bed combustor. Results from numerical simulations obtained using [Formula: see text] l- 𝜔 model were in good agreement with experimental data. Conditions tested cover five different secondary to total air ratios (Qs/Qt) and two different locations of secondary air injection. Results show that at Qs/Qt = 0.50, 0.25 and 0.18 one strong recirculation zone is induced upstream of the secondary air injection and one downstream. Varying the point of injection of secondary air from h/D = 0.64 to h/D = 0.40 also had an effect on the size of the upstream recirculation zone. Qs/Qt = 0.50 had the highest values of mixing index among all spatially located planes at the upstream of secondary air injection. The overall findings shed light on the possible flow interactions between secondary air and the top layers of fuel bed. They also highlight the significance of secondary air on inducing both upstream and downstream flow structures.

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“…The reduction of the ash fusion temperature also encourages the formation of slag on the surfaces in contact with the fuel bed. The fouling and slagging cause a decrease in thermal efficiency of the combustion systems, and may cause system damage [5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

CFD Simulation of an Internally Cooled Biomass Fixed-Bed Combustion Plant

et al. 2021

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The reduction of bed temperature in fixed-bed biomass combustion is an effective measure to lower pollutant emissions. Air staging and bed cooling solutions are active strategies to decrease the fuel bed temperature. This work presents a CFD study of a biomass fixed-bed combustion plant that is equipped with an internal cooling bed system. Eight different cases are calculated to analyze the effect of the total airflow, air staging ratios and bed cooling system on biomass combustion. The findings are validated against experimental data from the literature. The results show good accordance between the numerical results and the experimental data. The primary airflow rate has the biggest influence on the bed’s maximum temperatures. The internal bed cooling system is able to achieve an average bed temperature reduction of 21%, slowing the biomass thermal conversion processes. Bed cooling techniques can be combined with air staging and primary airflow reduction to reduce bed temperatures in order to reduce pollutant emissions and other undesirable phenomena, such as fouling or slagging.

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Eulerian CFD fouling model for fixed bed biomass combustion systems

Cited by 12 publications

References 33 publications

CFDs Modeling and Simulation of Wheat Straw Pellet Combustion in a 10 kW Fixed-Bed Downdraft Reactor

CFDs Modeling and Simulation of Wheat Straw Pellet Combustion in a 10 kW Fixed-Bed Downdraft Reactor

Secondary air induced flow structures and mixing in a fixed bed combustor

CFD Simulation of an Internally Cooled Biomass Fixed-Bed Combustion Plant

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