Flue gas desulfurization (FGD)
When coal is combusted in power stations to produce electricity, the sulfur contained within is released into the atmosphere as sulfur dioxide (SO2). The proportion of sulfur varies here depending on the quality and origin of the coal. Our dedicated calcium carbonate products Desulfocarb, Desulfonit and Epsical are added into the reaction chamber to remove the sulfur before it reaches the atmosphere. These flue gas desulfurization (FGD) products react chemically with the sulfur gas to form calcium sulfate (gypsum) as a by-product. Omya also offers solutions for the removal and further reuse of the produced gypsum to further increase the cost efficiency of the FGD process.
This reaction occurs in the furnace in the dry FGD process, where the calcium carbonate is burnt and reacts with the sulfur dioxide (SO2) to form calcium sulfate (gypsum). In the wet process, the chemical reaction takes place in the scrubber and gypsum is produced as a by-product. The gypsum can subsequently be used as an additive in cement, as a source of sulfur in fertilizers or in plasterboard manufacturing.
Depending on the process and the properties of Desulfocarb, Desulfonit or Epsical, over 95% of the sulfur can be removed. This is thanks to the use of dedicated calcium carbonates with the required high purity and a precise particle size distribution.