Category: Non-Regenerative FGD

In this category, the reagents used to remove the pollutant (mainly sulphur oxides) from the gas streams, are discarded. This results in the formation of calcium sulphate and carbon dioxide respectively following the reaction:

SO2 + Ca(OH)2 -> CaSO3 + H2O
SO2 + CaCO3 -> CaSO3 + CO2
CaSO3 + ½ O2 -> CaSO4

This kind of solution falls normally in the wet system, using double alkali processes. The wet systems can be designed to obtain not only gypsum, but, alternatively, calcium sludge, primarily CaSO3 .½ H2O.

Category: Regenerative FGD

Dry scrubbing or spray drying FGD: the reactant material is a slaked lime slurry or lime and recycled material slurry. Lime or soda hash can be used as reagents that is injected as a slurry or droplets in the flue gas and they absorb SO 2 while simutaneuosly being dried.

TECNIA provides the process engineeering, building and supply of the whole system for the spray drying vessel and additional equipments. The system can handle flue gases with high contents of SO2 . When using coals and other fuels up to 3,5% sulfur, the Regenerative FGD Dry Scrubbing is the adequate solution.