Symbols
Symbols
a Interfacial area, m-1
C Concentrazione mol m-3
CPi Molar heat capacity of i, J mol-1 K-1
D Diffusivity, m2 s-1
E Chemical enhancement factor for mass trasfer
Hi Molar enthalpy of i, J mol-1
(∆HR)j Reaction enthalpy of reaction j ,J mol-1
∆Hvap,i Molar heat of vaporization of i, J mol-1
h Heat trasfer coefficient,W m-2 K-1
K Chemical equilibrium costant of the formaldehyde hydration
k Reaction rate constant, m3 mol s-1
kd, kh Rate constants for the dehydration of methylene glycol, and the
pseudo-first-order
kg Gas phase mass trasfer coefficient, m s-1
kl liquid phase mass trasfer coefficient, m s-1
li liquid phase component molar flow rate, mol s-1
M Molar weight, kg mol-1
P Pressure, Pa
Psi Satured vapor pressure of i, Pa
q Conductive heat flux, W m-2
R Ideal gas costant, J mol-1 K-1
Ri Production rate by reaction of i, mol mol m-3 s-1
Re Reynolds number, d2 Nρ/η
Sc Schmidt number η/ ρD
Sh Sherwood number
T Temperature,T
V Volume, m3
v Diffusivity ratio (=DA,l/ DP,l in Charter 3; =DF,l/ DMG,l in Charter 4)
W Weight
WF Owerall weight percentage of formaldehyde in the liquid, wt %
Z Height of packing,m
γ Activity coefficient
δ Film thickness,m
εl Partial liquid holdup
η Viscosity,Pa s
vij Stoichiometric coefficient of component i in reaction j
ρ Density,kg m3
