$A$	Membrane transfer area	$\left[{\mathrm{m}}^2\right]$
$B$	Constant in Model II	$\left[-\right]$
$D$	Distillate product
${\overline{D}}_i$	Transport coefficient of component $i$	$\left[\mathrm{k}\mathrm{m}\mathrm{o}\mathrm{l}/\left({\mathrm{m}}^2\mathrm{h}\right)\right]$
${\overline{D}}_i^{*}$	Relative transport coefficient of component $i$	$\left[\mathrm{k}\mathrm{m}\mathrm{o}\mathrm{l}/\left({\mathrm{m}}^2\mathrm{h}\right)\right]$
$E_i$	Activation energy of component $i$ in Equation (12) for temperature dependence of the transport coefficient	$\left[\mathrm{k}\mathrm{J}/\mathrm{m}\mathrm{o}\mathrm{l}\right]$
$F$	Feed
$i$	Component number
$j$	Component number
$J_{total}$	Total flux	$\left[\mathrm{k}\mathrm{g}/\left({\mathrm{m}}^2\mathrm{h}\right)\right]$
$J_i$	Partial flux	$\left[\mathrm{k}\mathrm{g}/\left({\mathrm{m}}^2\mathrm{h}\right)\right]$
N	Number of theoretical stages	[-]
$P$	Permeate
$p_{i0}$	Pure i component vapour pressure	$\left[\mathrm{b}\mathrm{a}\mathrm{r}\right]$
$p_{i1}$	Partial pressure of component $i$ on the liquid phase membrane side	$\left[\mathrm{b}\mathrm{a}\mathrm{r}\right]$
$p_{i3}$	Partial pressure of component $i$ on the vapour phase membrane side	$\left[\mathrm{b}\mathrm{a}\mathrm{r}\right]$
$p_3$	Pressure on the permeate side	$\left[\mathrm{b}\mathrm{a}\mathrm{r}\right]$
$P_i/\delta$	Permeance of component $i$	$\left[\mathrm{m}\mathrm{o}\mathrm{l}/\left({\mathrm{m}}^2 \mathrm{h} \mathrm{b}\mathrm{a}\mathrm{r}\right)\right]$
Q0	Permeability of the porous supporting layer of the membrane	[$\mathrm{k}\mathrm{m}\mathrm{o}\mathrm{l}/\left({\mathrm{m}}^2 \mathrm{h} \mathrm{b}\mathrm{a}\mathrm{r}\right)$]
$R$	Retentate
Ʀ	Gas constant	$\left[\mathrm{k}\mathrm{J}/\left(\mathrm{k}\mathrm{m}\mathrm{o}\mathrm{l} \mathrm{K}\right)\right]$
$T$	Temperature	$\left[°C\right]$
$T^{*}$	Reference temperature: 293 $K$
$x_F$	Feed n-propanol weight fraction in $y-x$ vapour-liquid equilibrium (VLE) diagram (Figure 5)	$\left[-\right]$
$x_{i1}$	Concentration of component $i$ in the feed	$\left[\mathrm{m}/\mathrm{m}\%\right]$
$y$	Permeate n-propanol and water weight fraction in $y-x$ vapour-liquid equilibrium (VLE) diagram (Figure 5)	$\left[-\right]$
$y_i^{PV}$	Permeate concentration in Membrane Flash Index (MFLI)	$\left[\mathrm{m}/\mathrm{m}\%\right]$
$y_i^D\left[VLE\right]$	Equilibrium distillation value in Membrane Flash Index (MFLI)	$\left[\mathrm{m}/\mathrm{m}\%\right]$