Collect. Czech. Chem. Commun. 1996, 61, 825-836

Comparison of the Reactivity of Different Sodium Compounds and Ca(OH)2 Towards SO2 and Mixtures of SO2 and NOx

Karel Mocek, Květoslava Stejskalová, Pavel Bach, Erich Lippert, Zdeněk Bastl, Ilona Spirovová and Emerich Erdös

J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, 182 23 Prague 8, Czech Republic


The reactivity of solid substances towards acid gases (SO2, NOx) was studied with a view to finding the best conditions for an efficient removal of the gases. The solids included various sodium compounds (sodium bicarbonate, active soda, sodium carbonate monohydrate, dense soda ash) and Ca(OH)2, and the reaction with sulfur dioxide was examined over a broad range of experimental variables (temperature, gas composition). The reactivity of selected samples was also investigated in reactions with gaseous mixtures containing SO2 and NOx in the dependence on temperature, the SO2/NOx and NO/NO2 ratios and the hydrodynamic conditions of the fixed bed flow reactor. The ESCA and SEM techniques were employed to identify the solid reaction products and to study their evolution as a function of reaction parameters. It was found that with the NaHCO3 precursor, a simultaneous removal of 90% SO2 and nearly 50% NOx is feasible. The results indicate that NaHCO3 shows promise particularly for the purification of waste gases from incinerators and power plants.

Keywords: Sulfur dioxide; Nitrogen oxides; Waste gases purification; Dry processes.