Experimental and numerical study of mass transfer efficiency in new wire gauze with high capacity structured packing

ABSTRACT

Experimental and numerical studies were conducted on the mass transfer efficiency of new wire gauze structured packing. For serving this purpose, various operational conditions were studied to assess the optimal parameters such as HETP of PACK-2100 in the distillation column. The results indicate that the HETP values are enhanced in comparison to conventional ones. In addition, the HETP slowly increases from 4 to 6 cm as mass flow rates of air and liquid flow are increased. The numerical simulations were also performed to describe the performance of the PACK-2100. The Eulerian-Eulerian multiphase approach is applied to calculate the value of HETP and pressure drop. The computational results confirmed that our experimental results. The average relative error between CFD predictions and the experimental data for the prediction of mass transfer efficiency is 20.45%.

KEYWORDS:

• Structured packing
• HETP
• numerical simulation
• computational fluid dynamics
• mass transfer efficiency

Nomenclature

ap	=	Specific surface area of packing, [m2/m3]
ae	=	Effective area of packing, [m2/m3]
b	=	Corrugation base dimension, [m]
E	=	Relative error, [%]
Fs	=	Gas capacity factor, uG(ρG) 0.5, [m/s (kg/m3) 0.5]
FrL	=	Froude number for the liquid, [-]
g	=	Gravitational acceleration, [m s−2]
h	=	Corrugation crimp height, [m]
HETP	=	Height equivalent to a theoretical plate, [m]
HG	=	Height of a gas-phase transfer unit, [m]
HOG	=	Height of an overall gas-phase transfer unit, [m]
KL	=	Liquid-phase mass transfer coefficient, [m/s]
KG	=	Gas-phase mass transfer coefficient, [m/s]
MA	=	Molecular weight of component A, [kg/mol]
m	=	Slope of equilibrium line, [-]
${\dot{m}}_{LG}^A$	=	Mass transfer rate, [kg/m3 s]
N	=	Number of phases, [-]
NC	=	Number of components in each phase, [-]
NT	=	Number of theoretical units [-]
P	=	Pressure, [Pa]
$\mathrm{\Delta }P$	=	Pressure drop, [Pa]
ReL	=	Reynolds number for the liquid, [-]
S	=	Corrugation side length, [m]
t	=	Time, [s]
T	=	Temperature, [oC]
u	=	Velocity, [m/s]
UgS	=	Superficial gas velocity, [m/s]
Z	=	Packed height, [m]
Dh	=	Hydraulic diameter, [m]
xA	=	Mole fraction of component A in the liquid phase, [-]
XA	=	Mass fraction of component A in the liquid phase, [-]
x*A	=	Equilibrium mole fraction of component A in the liquid phase, [-]
xlA	=	Interfacial mole fraction of component A in the liquid phase, [-]
yA	=	Mole fraction of component A in the gas phase, [-]
YA	=	Mass fraction of component A in the gas phase, [-]
y*A	=	Equilibrium mole fraction of component A in the gas phase, [-]
ylA	=	Interfacial mole fraction of component A in the gas phase, [-]

Greek Symbols

α	=	Corrugation angle, [o]
β	=	Crimping angle, [o]
ε	=	Porosity, [-]
Ω	=	Fraction of packing surface area occupied by holes, [-]
γ	=	Volume fraction, [-]
ρL	=	Liquid density, [kg/m3]
ρ	=	Density, [kg/m3]
μ	=	Viscosity, [Pa.s]
δ	=	Liquid film thickness, [m]
λ	=	Ratio of slope of equilibrium line to operating line, [-]
σ	=	Surface tension, [N/m]
Γ	=	Dispersion coefficient, [kg/m s]

Subscripts

G	=	Gas phase
i	=	Index
L	=	Liquid phase