The aim of this work is to study experimentally the performance of a continuous countercurrent liquid-liquid extraction system, for the purification of an acetic acid extraction solution in a blue petroleum solution, using distilled water as solvent. We studied the effect of operating conditions, such as solution and solvent flow rates, and stirring speed, on separation performance as well as on the theoretical number of column stages. The number of theoretical stages was calculated using two graphical methods: the ternary diagram, MAC CABE and THIELE.