c	concentration of species (mol/m3)
d 1	membrane inside diameter (m)
dh	hydraulic diameter (m)
dlm	logarithmic diameter (m)
$D_{j,i},D_{j,mem}$	diffusion coefficient of species j in phase i and membrane (m2/s)
E	enhancement factor (-)
$H_{C{O}_2}$	Henry’s coefficient of CO2 in the liquid MEA solution (-)
$J_{C{O}_2}$	CO2 mass transfer flux from gas to liquid (mol/m2 s)
$k_{C{O}_2,i},k_{C{O}_2,mem}$	partial CO2 mass transfer coefficient in the i phase and through membrane pores (m/s)
$K_L$	global CO2 mass transfer coefficient (m/s)
L	membranes length (m)
n	number of membranes (-)
P	pressure (bar)
Q	volumetric flow rate (m3/s)
r 1	membrane inside radius (m)
r 2	membrane outside radius (m)
rmod	module inner radius (m)
rp	average membranes pores radius (m)
$R_{C{O}_2}$	reaction rate (mol/m3 s)
Re	Reynolds number (-)
Sc	Schmidt number (-)
Sh	Sherwood number (-)
T	temperature (K)
u	superficial fluid velocity (m/s)
Superscripts/subscripts
i	gas (g) and liquid (L) phase
j	system components
Greek letters
${\delta }_{mem}$	membrane thickness (m)
${\epsilon }_{mem}$	membrane porosity (-)
$\mu$	dynamic viscosity (Pa s)
$\rho$	fluid density (kg/m3)
${\tau }_{mem}$	membrane tortuosity (-)