Wet gas desulphurisation plants

Flue gas desulphurisation by the lime-gypsum method represents a classical absorption process that allows the removal of sulphur oxides (SOx) from flue gases (medium to high flow rates and chemical loads), at a reasonable cost. Flue gas desulphurisation (FGD) plants by the lime-gypsum method are used in:

  •     industrial power plants and combined heat and power plants fired with coal or heavy oil,
  •     waste and special waste incineration plants,
  •     chemical and petrochemical process plants,
  •     thermal process plants – e.g. calcination, sintering or roasting


Although FGD plants operating according to the lime-gypsum method belong to the so-called wet methods, the majority of the plants completed by STEULER-KCH to date do not produce any waste water.


Acidic sulphur oxides in gaseous form are absorbed by the washing liquid and then, in the process of reacting with the added absorbent, convert into an insoluble and usable gypsum end product which is removed from the process by filtration.


Low-cost calcium compounds, i.e. limestone or lime, are most often used as absorbents; in exceptional cases, compounds such as ZnO, Mg(OH)₂ or seawater are also possible. As the gypsum is sent for further industrial use as raw building material, there are no additional costs associated with waste storage. A complementary technology for flue gas desulphurisation (DeSOx) is, especially for smaller flue gas flows, so-called chemical absorbers based on neutralisation reactions with lyes (e.g. NaOH, NaHCO₃, KOH, etc.).


Flue gas absorbers with tower diameters of up to 4-5 metres, can be prefabricated in our workshops and shipped to the site indicated by the customer ready for installation. Absorbers with larger diameters, which cannot be transported, are built on site using STEULER-KCH’s innovative method of joining reinforced concrete with the BEKAPLAST™ lining system mechanically anchored in it.