Modeling and measurement of sulfur dioxide absorption rate in a laminar falling film reactor

Abstract

A kinetic study of sulfur dioxide absorption in a laminar falling film reactor is presented. A theoretical study is carried out taking into account mass transfer with chemical reaction in the liquid phase and parabolic velocity profiles in both phases. The transport equations are solved by a Runge–Kutta–Merson integration and a Newton–Raphson iteration method. The experimental study consists of measurements of sulfur dioxide concentration with respect to axial and radial position. Four different liquid phases are used: 0.5 M sulfuric acid solution (no reaction in liquid phase), 1.5 M sodium hydroxide solution (instantaneous surface reaction) and two organic solvents, N-Methyl-2-pyrrolidone and N-N′-Dimethylpropylene urea (equilibrium reaction in liquid phase). A good qualitative agreement is found between the experimental and theoretical profiles. Lack of reliable quantitative information is due to the gas sampling probes which induced perturbations in the gas phase. For the organic solvents the experimental absorption flux is about 80% of the maximum value, obtained with sodium hydroxide solution.