Evaluating the Thermodynamics and Kinetics of Production of Caustic Soda from Brine

Abstract

This work is detailed towards ascertaining the thermodynamics and kinetics considerations for the production of caustic soda from brine and soda ash. The thermodynamics considers the Gibbs free energy; which is the minimum electrical work that must be supplied to an electric cell to drive the electrochemical reactions and its relationship with other thermodynamic parameters. The kinetics aspect of this research deduces the reaction rate equations and also predicts via feasible calculations the rate of the reaction, rate constant and order of the reaction. The examination of the thermodynamic analysis shows that the reaction is exothermic, positive value of entropy indicates that there is intrinsic energy which can be converted into work by a perfect electrolytic reaction process. The work determines the extent and the rate of the production process of caustic soda production and as such a pilot plant production of caustic soda from naturally occurring seawater via the diaphragm cell may be developed. The results obtained have shown that the cell potential using the Nerst equation for the production of optimum product caustic soda are: E = 0.5232 volt and the reaction is of second order. The rate of the reaction r=6.264×10−12 mol⋅cm−2⋅s−1 and the rate constant K2=9.2591×10−5cm⋅s−1.