c ombination d evices - l iquid -p hase and g as -p hase c ontacting s crubbers sven stolle
DESCRIPTION
C YCLONIC SPRAY combination of dry cyclone and spray chamber capable of effectively removing some gases (but only for very soluble gases) Rarely chosen when gaseous pollutant removal is the only concern Not useful for removing submicrometer particles Maintenance problems: erosion (high velocities) and nozzle plugging Low-medium energy device Applications: Mining operations, Drying operations, Food processing, FoundriesTRANSCRIPT
COMBINATION DEVICES - LIQUID-PHASE AND GAS-PHASECONTACTING SCRUBBERS
Sven Stolle
COMBINATION DEVICES Wet-collector scrubbers that use energy from both the gas
stream and liquid stream to collect pollutants
E.g. • Cyclonic spray• Mobile bed• Baffle spray• Mechanically aided scrubbers
CYCLONIC SPRAY combination of dry cyclone and spray
chamber capable of effectively removing some gases
(but only for very soluble gases) Rarely chosen when gaseous pollutant
removal is the only concern Not useful for removing submicrometer
particles Maintenance problems: erosion (high
velocities) and nozzle plugging Low-medium energy device Applications: Mining operations, Drying
operations, Food processing, Foundries
MOBILE-BED / MOVING-BED SCRUBBERS
similar to packed towers, but bed is in constant motion
gas stream keeps the packing in motion, while liquid is sprayed over the packing
good collection efficiency for particulate and gaseous pollutants
packing is made of polypropylene or polyethylene plastic balls
particles as small as 2 to 3 μm can be removed but not submicrometer particles
high gaseous-pollutant removal efficiencies Maintenance problems: nozzle plugging,
deterioration of the spheres (e.g. in high temperatures)
Applications: Mining operations, Pulp mills, Utility boilers, Food industry
BAFFLE SPRAY SCRUBBERS similar to spray towers, but additionally gas
streams atomize the liquids by passing the baffles
Liquid sprays capture pollutants and also remove collected particles from the baffles
Particles larger than 10 μm can be removed Not specifically used for gas collection Low efficiencies Low Maintenance problems Applications: Mining operations, Incineration,
Chemical process industries
MECHANICALLY AIDED SCRUBBERS
Motors to supply energy Less space required than other scrubbers Higher power requirements high collection efficiencies for particles with
diameters >1 μm not used for gas absorption Maintenance problems: moving parts Applications: Mining operations, Food product
industries, Chemical industry, Foundries and steel mills
centrifugal-fan scrubbers
mechanically induced spray scrubbers