More than 25 years ago, Niro modernised spray drying, through an invention
by which spray dryers could absorb the acid gases present in combustion gases.
The Niro Spray Drying Absorption - SDA - process has since its commercial
recognition in the late 1970's been installed at more than 100 locations,
primarily at coal-fired power generating stations and at waste incinerators.
Since the early 1980's, the technology has found similar and widespread
application in North America and in Europe, just as the process gained a strong
foothold in the Far East during the 1990's.
Today, the Niro SDA process
has developed into a mature and very versatile technology which has found
application in combustion plants ranging from small household waste
incinerators to large coal-fired boilers. The process has also been applied to
flue gas cleaning at industrial plants. This cleaning is often combined with a
treatment of effluent or other waste streams.
The Niro SDA process for
flue gas cleaning is very simple as it basically consists of the SDA module, a
down-stream fabric filter, a reagent preparation system and a product handling
system.
Hot, untreated flue gas, when introduced into a spray dryer
absorption chamber contacts a fine spray of reagent slurry. A significant part
of the acidic components in the flue gas are rapidly absorbed into the alkaline
droplets, water being evaporated simultaneously. Control of gas distribution,
slurry flow rate and droplet size ensure that the droplets are dried to a fine
powder before they touch the chamber walls of the spray dryer absorber.
A portion of the dry product, consisting of fly ash and reaction
product, drops to the bottom of the absorption chamber and is discharged. The
treated flue gas flows to a particle separator, where the remaining suspended
solids are removed. Outlet gases from the particulate separator pass on to the
stack by means of an induced draft fan.
SPECIAL FEATURES:
- High acid gas removal efficiencies
- High plant availability
- Low capital cost
- Low power consumption
- Low operating and maintenance cost
- Low water consumption
- Utilize low water quality
NIRO SDA REFERENCES:
- Total plants built: 112
- Total number of absorbers: 230
- Total number of atomizers: 326
- Process installed at 10.400 MWe and 4.300 MWt power plant capacity
- Process installed at more than 100 incineration lines worldwide