Experimental Investigation and Modeling of Liquid-Li quid Equilibria in Water - Hydrazine - Butanol Ternary Systems

For hydrazine producing with concentration more than 64 wt%, remaining amount of water in hydrazine Hydrate, could not be removed easily to produce hydrazine with concentration more than 64wt%. In this work, Butanol, an aliphatic alcohol with four carbone atoms, was used as a solvent in liquid - liquid extraction of hydrazine. The binodal curve and the experimental tie lines for the ternary {water (1) – hydrazine (2) – butanol (3)} system were determined by cloud point method using the refractive index criteria at the temperatures of 15.2, 25.2 and 40.2 C, in atmospheric pressure. The distribution coefficient of Hydrazine (D) and its separation factor (S) were determined equal to 0.0425-0.3628 and 0.2768- 1.5179, in the usage concentration and temperature ranges, respectively. Afterword the experimental tie lines were correlated by the Non-Random Two-liquid model (NRTL) and the Universal Quasi Chemical model (UNIQUAC) with Root Mean Square Deviation (RMSD) equal to 0.0227 and 0.0495, respectively. In addition, the sodium hydroxide addition effect was studied on equilibrium behaviour of the system at 25.2 C. Addition of 10 wt% NaOH causes an increase of 13.16 % in the average distribution coefficient of hydrazine as well as 96.26% in the average separation factor.