Abstract
Flow mal-distribution in the shell side of the gas-cooled conventional reactor (CR) in the mega methanol plant is responsible for producing gas condensate in the catalytic zone. This phenomenon leads to catalyst agglomeration and efficiency reduction in the reactor. In this study, two novel and viable strategies, possible to be implemented in working reactors, are introduced to prevent condensation. In the first strategy, co-current mode (CCM), the reactant flow changes from counter-current into the co-current. In this regard, the feed inlet is replaced from the bottom of the reactor into the top. In the second strategy, changed-bed mode (CBM), the catalyst particles at the last two meters of the reactor are replaced with non-reactive ceramic balls. The results for three-dimensional computational fluid dynamics (CFD) in CR have been validated against previous study and industrial data, indicating close agreement. The main advantage of CCM and CBM is that the sudden temperature drop fails to occur at the end of the reactor. Consequently, the higher temperature of the products prevents water and methanol condensation. In addition, the CCM leads to a milder temperature profile throughout the shell side, which increases catalyst durability.
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Abbreviations
- A0 :
-
model constant
- As :
-
model constant
- C1 :
-
model constant
- C1ε :
-
transport equations constant
- C2ε :
-
transport equations constant
- G k :
-
turbulence kinetic generation of mean velocity gradients
- C p :
-
heat capacity
- n:
-
number of recorded data
- dp :
-
diameter of the particles
- Cμ :
-
model constant
- Dm,i :
-
diffusion coefficient
- E:
-
total energy
- G b :
-
turbulence kinetic generation of buoyancy
- Ki:
-
equilibrium constant
- DEN:
-
parameter in the reaction rate expressions
- J:
-
diffusion mass flux
- keff :
-
effective thermal conductivity
- m:
-
mass fraction
- h:
-
enthalpy
- p:
-
pressure
- Ri :
-
total reaction rate
- S h :
-
chemical reaction heat
- S k :
-
user-defined source terms
- Sε :
-
user-defined source terms
- f:
-
fugacity
- T:
-
temperature
- u:
-
velocity element
- yi :
-
recorded data
- ȳ:
-
average of recorded data
- U:
-
model parameter
- V:
-
velocity vector
- υ :
-
kinetic viscosity
- x:
-
length of the reactor
- Ym :
-
fluctuation dilation incompressible turbulence to dissipation rate
- ΔH298 :
-
reaction enthalpy at 298 K
- k′, ki :
-
kinetic parameters
- RGWS:
-
reverse water gas shift
- μ :
-
gas dynamic viscosity
- ε :
-
kinetic energy dissipation rate
- ρ :
-
density
- β :
-
parameter in the reaction rate
- MeOH:
-
methanol
- σ k :
-
turbulent Prandtl numbers for k
- σ ε :
-
turbulent Prandtl number for ε
- τ :
-
shear stress
- γ :
-
porosity
- δ ij :
-
Kronecker Delta
- eff:
-
effective
- f:
-
fluid
- s:
-
solid
- g:
-
gas
- Ref:
-
reference point
- i, j:
-
components
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The authors are grateful to the Shiraz University for supporting this research.
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Keramat, F., Mirvakili, A., Shariati, A. et al. Investigation of anti-condensation strategies in the methanol synthesis reactor using computational fluid dynamics. Korean J. Chem. Eng. 38, 2020–2033 (2021). https://doi.org/10.1007/s11814-021-0916-z
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DOI: https://doi.org/10.1007/s11814-021-0916-z