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DESCRIPTIONS
Contaminant removal is achieved by absorption of gases and vapors,
condensation of condensable vapors and impaction of aerosols. All
mechanisms occur in a packed bed for intimate gas-liquid contacting.
Contaminants transferred to the liquid phase are removed from the
scrubber by continuous or periodic overflow of blowdown.
F103 and F105 Packed Bed Wet Scrubber. Horizontal crossflow
design minimizes height requirement and is ideal for roof mounting
with remote recirculation. Standard unitsup to 63,000 CFM.
FW303 and FW305 Packed Bed Wet Scrubber. Integral fan makes
this vertical counterflow unit very compact. Standard units up to
17,500 CFM.
PT503 and PT505 Packed Bed Wet Scrubber. Maximizes mass transfer
efficiency while minimizing footprint requirement.
Standard units up to 25,000 CFM.
MIST ELIMINATION
Turbulent gas-liquid contacting causes some droplets to become entrained
in the air. The mist eliminator collects these droplets that would
otherwise be ejected from the scrubber.
WATER SUPPLY
All Duall fume scrubbers must be supplied with water. It is generally
recommended that a recirculation system be used to conserve water
unless once through water is advantageous to meet performance requirements.
The actual fresh-water consumption with recirculation is only 0.1
to 0.7 gpm/1000 cfm* depending on the contaminant involved. Duall
scrubbers
with remote recirculation systems are self-draining and may be installed
outdoors in sub-zero conditions without freeze-up. If these conditions
exist, the recirculation tank should be placed in a heated area.
A complete chemical metering and pumping system is available upon
request. For applications involving gases with low solubility, chemical
addition is required for liquid recirculation.
* Fresh-water consumption can vary depending on the solubility of
contaminants.
INSTALLATION
Every Duall fume scrubber is shipped completed with an integral
coated steel base. No special mounting is required. Simply connect
the duct, the water and power supply, and the unit is ready for
operation. Complete installation and operating instructions are
supplied with all scrubbers, or Duall’s trained staff can install
equipment quickly and efficiently.
PRESSURE
DROP
The following pressure drops are applicable for scrubbers
operated at design:
F103
2.0" w.g
F105 2.5" w.g
FW303 2.0" w.g |
FW305
2.5" w.g.
PT503 2.0" w.g.
PT505 2.5" w.g. |
On the FW series,
the blower is designed for 2.0" external static pressure.
FW BLOWER
SECTION
The top section of the FW fume scrubber consists of a Duall centrifugal
blower complete with TEFC motor and OSHA belt and
shaft guards. The blower section may be rotated through 360°
to obtain any desired angle between scrubber inlet and blower outlet.
This blower section utilizes the same lowmaintenance, guaranteed
corrosion-resistant blower described in Duall Brochure No. CINH
151.
MAINTENANCE
The Duall fume scrubber incorporates low-maintenance components
in its entirety, including the packing, plumbing system and eliminators.
Spray header access doors, differential pressure gauges, heavy duty
flanges, packing removal doors are all critical points differentiating
the product from a number of its competitors.
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SCRUBBER
REMOVAL EFFICIENCY FOR VARIOUS APPLICATIONS
| CONTAMINANT |
3
Ft Bed
Series |
With
pH
Control |
5
Ft.Bed
Series |
With
pH
Control |
| Acetic
Acid |
NR |
80-85 |
NR |
90-95 |
| Alcohols
3 |
* |
* |
* |
* |
| Alkaline
Cleaners 4 |
99.5-99.9 |
99.5-99.9 |
99.9 |
99-9 |
| Amines |
NR |
90-95 |
NR |
98-99 |
| Ammonia |
NR |
90-95 |
NR |
98-99 |
| Aqua
Regia 1, 5 |
85-90 |
86-92 |
95-98 |
96-98 |
| Arsine
2 |
NR |
80-85 |
NR |
85-90 |
| Boric
Acid 4 |
96-98 |
96-98 |
98 |
98 |
| Caustic
Cleaners 4 |
99.5-99.9 |
99.5-99.9 |
99.9 |
99.9 |
| Caustic
Soda 4 |
99.5-99.9 |
99.5-99.9 |
99.9 |
99.9 |
| Chlorine
6 |
NR |
85-90 |
NR |
95-98 |
| Chromic
Acid 4 |
98-99 |
98-99 |
99 |
99 |
| Copper
Chloride 4 |
90-92 |
90-92 |
92 |
92 |
| Cyanide
Solutions 4 |
99.5-99.9 |
99.5-99.9 |
99.9 |
99.9 |
| Diborane
2 |
NR |
90-95 |
NR |
95-98 |
| Ethylene
Oxide 3 |
* |
* |
* |
* |
| Ferric
Chloride 4 |
93-95 |
93-95 |
95 |
95 |
| Ferric
Nitrate 4 |
98-99 |
98-99 |
99 |
99 |
| Ferrous
Chloride 4 |
98-99 |
98-99 |
99 |
99 |
| Ferrous
Sulfate 4 |
98-99 |
98-99 |
99 |
99 |
| Fluoborate
Mists 4 |
98-99 |
98-99 |
99 |
99 |
| Fluosilicic
Acid 4 |
98-99 |
98-99 |
99 |
99 |
| Formaldehyde |
NR |
85-90 |
NR |
98-99 |
| Halide
Mists 4 |
96-98 |
96-98 |
98 |
98 |
| Hydrochloric
Acid 1, 5 |
90-95 |
92-96 |
95-99 |
98-99 |
| Hydrofluoric
Acid 1 |
95-98 |
96-98 |
96-99 |
98-99 |
| Hydrofluosilicic
Acid 4 |
98-99 |
98-99 |
99 |
99 |
| Hydrogen
Cyanide 1,2 |
NR |
85-90 |
NR |
95-98 |
| Hydrogen
Peroxide |
90-95 |
90-95 |
95-99 |
95-99 |
| Hydrogen
Sulfide 2 |
NR |
70-75 |
NR |
85-90 |
| Mercaptans
3 |
* |
* |
* |
* |
| Nickel
Chloride 4 |
93-95 |
93-95 |
95 |
95 |
| Nickel
Sulfate 4 |
98-99 |
98-99 |
99 |
99 |
| Nitric
Acid 1, 5 |
85-90 |
86-92 |
95-98 |
96-98 |
| Nitric
Oxide (NO) 3 |
* |
* |
* |
* |
| Nitrogen
Dioxide (NO2)3 |
* |
* |
* |
* |
| Perchloric
Acid 5 |
80-85 |
80-85 |
85-90 |
95-98 |
| Phenol
2 |
NR |
70-75 |
NR |
85-90 |
| Phosphine
2 |
NR |
85-90 |
NR |
90-95 |
| Phosphoric
Acid 4 |
96-99 |
96-99 |
98-99 |
98-99 |
| Potassium
Dichromate 4 |
98-99 |
98-99 |
99 |
99 |
| Selenium
Sulfide 1 |
98-99 |
98-99 |
99 |
99 |
| Silane |
NR |
96-98 |
NR |
99 |
| Sodium
Chloride 4 |
98-99 |
98-99 |
99 |
99 |
| Sodium
Fluoride 4 |
98-99 |
98-99 |
99 |
99 |
| Sodium
Glutenate 4 |
98-99 |
98-99 |
99 |
99 |
| Sodium
Hydroxide 4 |
99.5-99.9 |
99.5-99.9 |
99.9 |
99.9 |
| Sulfamate
Mists 4 |
98-99 |
98-99 |
99 |
99 |
| Sulfur
Dioxide |
NR |
80-85 |
NR |
92-96 |
| Sulfuric
Acid 4 |
99.5-99
9 |
99.5-99
9 |
99
9 |
99.9 |
| Tin
Chloride 4 |
90-95 |
90-95 |
95 |
95 |
| Zinc
Chloride 4 |
90-95 |
90-95 |
95 |
95 |
| Zinc
Nitrate 4 |
98-99 |
98-99 |
99 |
99 |
| Zinc
Sulfate 4 |
98-99 |
98-99 |
99 |
99 |
These efficiencies
are intended only as a guide. Specific combinations and concentrations
of fumes may result in significant variation from these values.
1. The use of pH control for these applications reduces water usage.
2. Performance is improved by chemical addition (other than for
pH control).
3. These applications require extended packing depth and chemical
addition (other than for pH control) or
once-through water.
4. Wet scrubbing is not necessary; only a mist elimination device
is needed, such as Duall Mist Misers or
Chemical Mist Eliminators. Expected efficiencies on fumes from molten
salt baths using the indicated salt
will be less than those shown for aqueous mists; efficiencies on
molten salt bath applications will range
from 70-90%.
5. Under certain conditions such as high loadings or high process
temperature, a fine fog forms which will
not be removed at the stated efficiencies. A special high efficiency
mist eliminator is required.
6. For applications involving high levels of chlorine, consult Duall
Division, Met-Pro Corporation.
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