Vol-2 Issue-3 2016 IJARIIE-ISSN (O)-2395-4396 2193 www.ijariie.com 613 Effect of Li-Br salt on azeotropic mixture of formic acid-water by extractive distillation Prajapati Chintan K 1 , Prof R.P.Bhatt 2 1 Student, Chemical engineering, L.D.College of engineering Ahmedabad, Gujrat, India 2 Assistant professor, Chemical engineering, L.D.College of engineering Ahmedabad, Gujrat, India ABSTRACT Separation and purification are an integral part and a major cost factor in the chemical industry. Distillation is a very commonly used for solvent separation and purification process. It is neither cost effective nor process efficient when dealing with close-boiling and azeotropic solvent mixtures without modifying the relative volatility of the solvent components with an extraneous solvent or a non-volatile solute electrolyte or nonelectrolyte. The selection of a suitable modifier generally depends on the experimental determination of its effect on the Vapour Liquid Equilibrium (VLE) of the solvent mixture. Formic is most widely used preservative and antibacterial agent in livestock feed .Aqueous Formic acid is obtained during these processes and recovery of which is of great significance. We would then require towers with large number of stages which would be operated with high reflux ratio and required high energy costs and operating costs. In practice extraction with suitable solvent is carried out before pure recovery occurs during the rectification of azeotropic mixture. An alternative separation process is the addition of Lithium Bromide (Li Br) salt into Formic acid water solution. Lithium bromide is largely soluble in water. Addition of salt will increase the boiling point of salt-water solution, there by separating comparatively pure Formic acid as overhead product. Li Br–water solution remains as residue from which Li Br can be readily separated by evaporation and reused Experiments are carried out in laboratory with different concentrations of Formic acid-water, in Othmer still which is vapor-liquid equilibrium apparatus. An Extractive distillation column will be designed based on experimental results. Cost analysis of this new separation technique will be carried out. The experimental data will be correlated to any model to calculate activity co efficients Keywords:- VLE, Extractive Distillation, Formic acid + water + Li-Br system 1. INTRODUCTION Separation and purification are an integral part and a major cost factor in the Chemical industry. Distillation, a very commonly used solvent separation and purification process is neither cost effective nor process efficient when dealing with close boiling and azeotropic solvent mixtures. The conventional method for separating these types of mixtures is to shift the azeotropic composition by altering column pressure or by using extractive distillation by addition of solvent to break the azeotrope. Separation by altering the column pressure is possible only if the pressure has a considerable effect on azeotropic composition. Moreover the extra separation step is needed to recover the solvent or to adjust the pressure which adds extra cost to the separation .Instead of adding a solvent a nonvolatile salt could be used as a separating agent to alter the VLE of a given mixture. It is envisioned that the ions of the added salt form association complexes more with the molecules of one of the components to be separated than with the other components. This association complex phenomenon may result in altering the vapour and partial pressures, solubility, thermal conductivity, density, surface tension etc. These changes may result in altering the VLE of the system, thus altering the ease of separation and shifting or eliminating the azeotropic point of a given mixture.