Abstract
This work investigated the suitability of biodiesel
(predominantly Methyl Linolenate, Methyl Palmitate, Methyl
Oleate and Methyl Stearate) as an absorbent for the recovery
of VOCs from waste gas process streams through absorption.
The objective was to predict the vapour liquid equilibria
(VLE) data in the form of infinite dilution activity coefficients
for five VOC families, in fatty acid methyl ester solvents at
varying temperature. The Original Universal Functional
Group Activity Coefficient (UNIFAC) model (Fredenslund et
al., 1975) [1], Modified UNIFAC (Larsen et al., 1981) [2] and
Modified UNIFAC (Bastos et al., 1988) [3] was used to predict
the required phase equilibrium. Alkanes, alcohols and
acids/ester interactions showed an increase in activity
coefficients with increase in temperature. The influence of
temperature on the activity coefficients for alkene and amine
families was negligible. The solubility of VOCs in biodiesel
decreases with increase in ester hydrocarbon unsaturation.
The solubility of VOCs increased with increase in ester
molecular weight.