Flue Gas Desulfurization Assessment by Modeling and Experimental Work of an Optimized Fixed-Bed NaHCO3 Reactor

Strengthening of environmental regulations demands novel or enhanced technologies for Flue Gas Desulfurization (FGD). A fixed-bed reactor using sodium bicarbonate (NaHCO3(s)) is proposed to eliminate sulfur dioxide (SO2) in flue gases up to the environmental regulation limits, leading to a maximum heat energy recovery. A numerical model was developed to fully characterize this reactor, based on fluidization, physicochemistry, hydrodynamic stability, and reaction properties. The model allows determining the replacement time of the sorbent bed by following the variations of the gas properties and progressive bed degradation. A prototype was built to parametrize and to validate the model regarding the hydrodynamic and reactions properties for granular NaHCO3(s) in nonstationary operation. Experimental studies were carried out for SO2 concentrations around 1500 ppmv and temperatures above 395 K. Finally, a technology assessment indicates possible capital and operating cost savings as compared to the conventionally used SO2 adsorption with activated carbon for small-scale FGD applications.