NUMERICAL SIMULATION OF WET FLUE GAS DESULPHURIZATION IN WET SPRAY ABSORBER

Abstract

A concise one-dimensional thermal-hydraulic two-fluid model is presented for the numerical prediction of sulphur dioxide absorption from the flue gas onto drops of the waterlimestone slurry in the vertical spray tower absorber. The model is based on mass, momentum and energy balance equations for each phase separately, i.e. downward falling droplets of water-limestone slurry and upward flowing flue gas. The sulphur dioxide content in the flue gas is predicted by a balance equation of the sulphur dioxide mass fraction in the flue gas. Interface transfer processes between the flue gas and the droplets are determined by closure laws. The obtained steady-state balance equations are transformed in a form suitable for a direct application of the numerical integration method for the system of ordinary differential equations. The developed thermal-hydraulic model is validated by comparing numerical results with available measured data at the large utility absorber. The presented results clearly show the dynamics of flue gas and droplets thermal-hydraulic processes and their influence on the absorption process. The influence of liquid-to-gas ratio and droplet diameter on sulphur dioxide removal efficiency has been investigated.