Experimental study of oil flue gas desulfurization in a pilot plant spray-dryer

The present paper reports an experimental investigation on SO2 removal in a pilot scale spray-dryer from the flue gas generated by combustion of low-sulfur heavy oil. The experimental facility is equipped with an oil burner which produces approximately 60 Nm3/h of flue gas with SO2 gas concentrations spanning up to 1200 mg/Nm3 depending on the oil sulfur content. A lime-water slurry is sprayed through an atomizer in the spray-dry chamber and the spent sorbent is collected downstream in a pulse-jet baghouse together with fly ash. Flue gas is sampled in different points in order to measure the desulfurization efficiency after both the spry-dry chamber and the baghouse. Parametric tests have been performed to study the effect of the following variables: gas inlet temperature (130-160°C), difference between gas outlet temperature and adiabatic saturation temperature (10-20°C), and lime to sulfur ratio (1-2). Results indicate that spray-drying is an effective technology for the desulfurization of low-sulfur fuel oil flue gas, provided operating conditions are chosen carefully. In particular the lowest gas inlet and outlet temperatures compatible with baghouse operation should be selected as well as a sufficiently high lime to sulfur ratio.