Liquid-liquid extraction of aromatics from hydrocarbon mixtures in capillaries

Abstract

An aromatics extraction study was conducted in capillaries of internal diameters in the range of 0.8 mm to 2 mm. The systems chosen for study were 'n-heptane + toluene + propylene carbonate', 'n-heptane + toluene + furfural' and 'synthetic naphtha reformate + (propylene carbonate + tetraethylene glycol)'. The aim of the work was to evaluate the feasibility of conducting aromatic separation in micro-capillaries and evaluate maximum efficiency. The results showed efficiencies ranging from 46.3 % to 97.3 %, depending upon the combination of the flow velocity, residence time and channel diameter. The effect of individual parameters on extraction efficiency was also isolated from the various combinations. Efficiency increased from 68 to 83 % as flow velocity increased from 0.11 to 0.96 cm/s, while residence time and channel diameter were fixed at 0.78 min and 2 mm, respectively. The samples collected from the capillary quickly separated into clear liquid layers, indicating short settling times.