Investigation of polymers pyrolysis in a solid-gas conical spouted bed: CFD simulation
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Sobhan Jafari
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Mortaza Gholizadeh
Abstract
The hydrodynamics of a conical spouted bed was simulated utilizing the Eulerian–Eulerian Two-Fluid Model (TFM) incorporating a kinetic theory of granular flows. The simulations were confirmed with experimental data. To accurately examine the pyrolysis process, the hydrodynamics of the solid bed as well as the heat transfer inside it were analysed separately by considering a precise synthetic model. The effects of gas velocity, particle size, bed length, and temperature were thoroughly investigated. The results indicated that the amount of relative standard deviation increases with an increase in the inlet velocity into the bed. This amount of deviation at the inlet velocity (0.6 m/s for tar and gas flow to its maximum value of 9.1 and 9.4) is not desirable in product production and should be modified so that the amount of gas flow increases and the tar produced reaches the minimum possible amount. Also, the graphs of the relative standard deviation in terms of temperature indicate that the increase in temperature from 730 to 950 K is associated with a relatively smaller fluctuation of the relative standard deviation so that at the temperature of 730 K, it is 7.2 % for tar and 6.4 % for gas flow, while at temperature of 950 K, it is 6.5 % for wire and 6.8 % for gas flow. Finally, the results determined that small-diameter particles have a more significant fountain height and also higher velocity in the spout section.
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Research ethics: Not applicable.
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Author contributions: The authors have accepted responsibility for the entire content of this manuscript and approved its submission.
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Competing interests: The authors state no conflict of interest.
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Research funding: None declared.
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Data availability: Not applicable.
Nomenclature
- d s
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The diameter of the solid particles
- g
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The gravitational acceleration
- g 0,ss
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The lateral distribution function
- K fs and K sf
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The momentum exchange coefficient between fluid phase f and solid phase s
- k Θs
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The diffusion coefficient
- P
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The static pressure shared by both phases
- P s
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The solid pressure source term
- S s
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The solid phase source term
-
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The velocity of phase q
- α q
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The volume fraction of phase q
- θ ss
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The coefficient of restitution
- Θ s
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The granular temperature
- ∇Θ s
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The collisional dissipation of energy
- λ q
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The bulk viscosity of phase q
- μ q
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The shear viscosity of phase q
- μ s,kin
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The kinetic viscosity
- ρ q
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The density of phase q
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The phase stress-strain tensor
- Φ fs
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The momentum transfers due to heterogeneous gas−solid reactions
Indices
- f
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stand for fluid phase
- s
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stand for solid phase
References
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- CFD-DEM simulation of chemical looping hydrogen generation in a moving bed reactor
- Conceptual design of a fixed bed N2O decomposition reactor with a heat pipe heat exchanger
- Investigation of polymers pyrolysis in a solid-gas conical spouted bed: CFD simulation
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Artikel in diesem Heft
- Frontmatter
- Articles
- Study on mixing characteristics of viscoplastic fluid in a rigid-flexible impeller stirred tank
- Emission and performance investigation of mango seed oil biodiesel supplied with n-pentanol and n-hexanol additives and optimization of fuel blends using modified deep neural network
- Study of chlorophyll dye from peppermint (mentha spicata) used as a sensitizer in TiO2 solar cells
- Dry reforming of methane over Ni–Mg–Al and Ni–Ca–Al type hydrotalcite-like catalysts: effects of synthesis route and Ru incorporation
- CFD-DEM simulation of chemical looping hydrogen generation in a moving bed reactor
- Conceptual design of a fixed bed N2O decomposition reactor with a heat pipe heat exchanger
- Investigation of polymers pyrolysis in a solid-gas conical spouted bed: CFD simulation
- CFD simulation study of internal mixing and flow of a modified airlift bioreactor
- Mechanism analysis and mixing characterization of variable-speed mechanical mixing enhancement
- Enhanced sonocatalytic degradation of Acid Red 27 with Fe2O3 catalyst: a kinetic study
