Scrubbing of SO₂ with trona solution in a spray drier

Abstract

Effect of operating variables on the scrubbing efficiency of SO2 in a spray drier was investigated using trona (Na2 CO3 · NaHCO3 · 2H2 O) solutions of different compositions. Results indicated that for a Na/S mole ratio of two (stoichiometric ratio) about 80% of the SO2 was removed. For higher Na/S ratios, SO2 removal efficiency increased by up to 100%. Increased SO2 concentration in the feed gas and decreased outlet temperature caused an increase in the overall conversion. At low temperatures and low SO2 concentration, the reaction takes place mainly between SO2 and Na2 CO3 As the temperature is increased, decomposition of NaHCO3 to Na2 CO3 and sorption reactions take place simultaneously.

Experimental Investigation of the Reactivity of Sodium Bicarbonate toward Hydrogen Chloride and Sulfur Dioxide at Low Temperatures

“…The presence of oxygen is clearly shown to slow down the overall reaction rate of SO 2 . This is likely due to the additional diffusional resistance in the transport of SO 2 to the reaction interface provided by the formation of Na 2 SO 4 . Owing to the occurrence of reaction , as mentioned before, the diffusion of oxygen toward the layer of solid products competes with the diffusion of SO 2 toward the reaction interface.…”

Modelling of trona based spray dry scrubbing of SO2

“…In limestone based scrubbing studies it is reported that the relative humidity should be over 70% [3]. The FGD studies using trona solution showed that 5% relative humidity is enough to remove the SO 2 with efficiency of 99% [15]. That means the reaction occurs at dry base.…”

“…Dogu et al reported that formation of Na 2 SO 4 causes an additional diffusion resistance for the transport of SO 2 to the reaction surface [15]. At low temperatures, formation of Na 2 S 2 O 5 was also expected during the reaction [16].…”

Numerical approaches and analysis of spray characteristics for pressuriser nozzles

“…A very typical example of such system is the spraying system in a pressuriser . The pressure‐swirl nozzle is an important type of nozzle, which is widely used in spray drying, scrubbing and combustion to obtain a large spraying field and small drop size. For its application in the pressuriser, the pressure‐swirl nozzle has an inevitable defect that the spray particles are not distributed uniformly in the container.…”