Experimental investigation of a pilot-scale jet bubbling reactor for wet flue gas desulphurisation

Abstract

In the present work, an experimental parameter study was conducted in a pilot-scale jet bubbling reactor for wet flue gas desulphurisation (FGD). The pilot plant is downscaled from a limestone-based, gypsum producing full-scale wet FGD plant. Important process parameters, such as slurry pH, inlet flue gas concentration of SO 2, reactor temperature, and slurry concentration of Cl − have been varied. The degree of desulphurisation, residual limestone content of the gypsum, liquid phase concentrations, and solids content of the slurry were measured during the experimental series. The SO 2 removal efficiency increased from 66.1% to 71.5% when the reactor slurry pH was changed from 3.5 to 5.5. Addition of Cl − (in the form of CaCl 2·2H 2O) to the slurry (25 g Cl −/ l) increased the degree of desulphurisation to above 99%, due to the onset of extensive foaming, which substantially increased the gas–liquid contact area. An increase in the inlet flue gas SO 2 concentration from 502 to 991 ppmv led to a decrease in the SO 2 removal efficiency from 80.1% to 69.4%. A temperature increase from 296 to 323 K caused a reduction in the degree of desulphurisation from 69.4% to 68.1%, but this result is almost within the experimental uncertainty. The residual limestone level in the gypsum formed increased with increasing values of reactor slurry pH, inlet flue gas SO 2 concentration, and slurry concentration of Cl −.