A comprehensive two dimensional Computational Fluid Dynamics model for an updraft biomass gasifier

Fernando, Niranjan; Narayana, Mahinsasa

doi:10.1016/j.renene.2016.07.057

Cited by 40 publications

(29 citation statements)

References 20 publications

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“…From these streamlines, it is shown that during combustion reactions (equation (16)), (equation (19)), and (equation (20)) at the upper zone of reaction chamber) there is vigorous mixing of combustion products due to concentric injection of feedstock and oxidant which produces high temperature, and combustion products mainly CO 2 and H 2 O leaving a portion of unburnt char particles. Those unburnt char particles then react with CO 2 and H 2 O as per gasification reactions (equation (17)) and (equation (19)) and produce CO and H 2 in the further length of the reactor (Chen et al., 2013; Fernando and Narayana, 2016).…”

Section: Resultsmentioning

confidence: 99%

Numerical simulation of lignocellulosic biomass gasification in concentric tube entrained flow gasifier through computational fluid dynamics

Maitlo

Unar

Mahar

et al. 2019

Energy Exploration & Exploitation

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Thermochemical conversion of biomass is an encouraging way for the production of syngas. In the present research, four different biomass materials were used for gasification which includes rice husk, cotton stalks, sugarcane bagasse, and sawdust. These biomass sources were selected because they are common Pakistani feedstocks. Gasification of selected biomasses was performed using concentric tube entrained flow gasifier. Three-dimensional computational fluid dynamics model was used to investigate the impacts of kinetic rate and diffusion rate on the gasification performance. The Euler-Lagrange method was used for the development of entrained flow biomass gasifier using commercial computational fluid dynamics code ANSYS FLUENT V R 14. Discrete phase model was used to predict the movement of particles, whereas the gas phase was treated as the continuous phase with a standard k-e turbulent model to predict the behavior of gas phase flow. Finite rate/Eddy dissipation model was applied for the calculation of homogenous and heterogeneous reaction rates. Oxygen was used as a gasifying agent. Cotton

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Section: Resultsmentioning

confidence: 99%

Numerical simulation of lignocellulosic biomass gasification in concentric tube entrained flow gasifier through computational fluid dynamics

Maitlo

Unar

Mahar

et al. 2019

Energy Exploration & Exploitation

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show abstract

“…Rate constants are given in Tab. 1 29, 30.

true r_{normalk normal, normali} = A_{normalc} A_{normali} T_{normals} normalexp (- E_{i} / R T_{s}) (M_{c} / M_{i}) ρ_{normali}

…”

Section: Mathematical Modelingmentioning

confidence: 99%

Effect of Turbulence of the Freeboard on Fluidized‐Bed Biomass Combustion

2020

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bed combustion is a very popular technology used to convert solid biomass into thermal energy, which has many advantages over other conversion technologies. However, these advantages strongly depend on the freeboard combustion. This study focuses on the effect of turbulence of the freeboard via developing a comprehensive mathematical model including four-way coupling, biomass thermal decomposition, and turbulent combustion by means of an Eulerian-Lagrangian framework. The validated model predicts with significant accuracy for all gas species when turbulence modeling is improved. The optimum amount of the secondary air ratio and the optimum excess air ratio were determined, which give a higher freeboard temperature while maintaining minimum emission.

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“…Due to the fixed-bed gasifier's simplicity, CFD is sufficient for gasification process simulation and prediction. An updraft biomass gasifier was studied by two-dimensional CFD (2D CFD) modeling to optimize air flow rate for CO production (Fernando and Narayana 2016). The simulation for the lab-scale updraft gasification experiment showed that a flow rate of 7 m 3 /h maximized CO yield.…”

Section: Introductionmentioning

confidence: 99%

Two-dimensional CFD simulation and pilot-scale experimental verification of a downdraft gasifier: effect of reactor aspect ratios on temperature and syngas composition during gasification

Siripaiboon

Sarabhorn

Areeprasert

2020

Int J Coal Sci Technol

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This paper focuses on a two-dimensional CFD simulation of a downdraft gasifier and a pilot-scale experiment for verification using wood pellet fuel. The simulation work was carried out via the ANSYS-Fluent CFD software package with in-house coding via User Defined Function. Three gasification parameters were taken into account in the simulation and validation to achieve highly accurate results; namely, fuel consumption, temperature profile, and syngas composition. After verification of the developed model, the effects of aspect ratios on temperature and syngas composition were investigated. Results from simulation and experimental work indicated that the fuel consumption rate during the steady state gasification experiment was 1.750 ± 0.048 g/s. The average steady state temperature of the experiment was 1240.32 ± 14.20 K. In sum, the fuel consumption and temperature profile during gasification from modeling and experimentation show an error lower than 1.3%. Concentrations of CO, CO2, H2, and CH4 were 20.42 vol%, 15.09 vol%, 8.02 vol%, and 2.6 vol%, respectively, which are comparable to those of the experiment: 20.00 vol%, 15.48 vol%, 8.00 vol%, and 2.65 vol%. A high concentration of syngas is observed in the outer radial part of the reactor because of the resistive flow of the air inlet and the synthesis gas produced. The average temperatures during the steady state of the gasifier with aspect ratios (H/D) of 1.00, 1.38 (experiment), and 1.82 were 978.77 ± 11.60, 1256.46 ± 9.90, and 1368.94 ± 9.20 K, respectively. The 1.82 aspect ratio reactor has the smallest diameter, therefore the radiative heat transferred from the reactor wall affects the temperature in the reactor. Syngas compositions are comparable. Inverse relationships between the aspect ratios and the syngas LHV, (4.29–4.49 MJ/N m3), cold gas efficiency (29.66% to 31.00%), and carbon conversion (79.59% to 80.87%) are observed.

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A comprehensive two dimensional Computational Fluid Dynamics model for an updraft biomass gasifier

Cited by 40 publications

References 20 publications

Numerical simulation of lignocellulosic biomass gasification in concentric tube entrained flow gasifier through computational fluid dynamics

Numerical simulation of lignocellulosic biomass gasification in concentric tube entrained flow gasifier through computational fluid dynamics

Effect of Turbulence of the Freeboard on Fluidized‐Bed Biomass Combustion

Two-dimensional CFD simulation and pilot-scale experimental verification of a downdraft gasifier: effect of reactor aspect ratios on temperature and syngas composition during gasification

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