- Bag filters
- Gas conditioning
- Dry deacidification
- Wet deacidification
- De-NOX SNCR
- De-NOX SCR
- Dust handling
The wet treatments involve the elimination of the acid gases through saturation of the flue gas via water injection.
These systems are generally composed of “scrubbing towers” made from acid-resistant material.
The elements constituting the system may be as follows:
– Acid tower, for HCI treatment and HG treatment (if requested)
– Basic or neutral tower, for SO2 treatment
– Undercooling stage, to obtain heat recovery by condensing the humidity of the flue gas
The neutralisation of the acid gases takes place at the different stages through washing with water and reaction with a basic reagent, usually milk of lime and/or soda.
The injection of the reagent may take place directly in the tower, in the discharge or in the water-treatment line that manages the liquid effluent of the plant. Area Impianti has created systems in which the discharge, following a mild treatment, is recycled in another phase of the process, with the consequent complete elimination of the liquid effluent from the plant.
The scrubbing towers used by Area Impianti are tray or packed types.
In addition to the wet and dry systems, Area Impianti also produces “semi-wet” systems with the injection of a suspension of lime in water (“milk of lime”) prepared on site.
The suspension is injected into appropriate reactors using rotary spray nozzles that allow for the proper distribution and complete evaporation of the water of the suspension.
While high levels of performance can be achieved with these systems, specific solutions need to be implemented to avoid the equipment becoming excessively dirty.