Packed Bed Fume Scrubbers and Wet Air Scrubbers
Common contaminates removed by Monroe Packed Bed Fume Scrubbers include:
Wet Air Scrubber Features
- Materials of construction include:
- PVC and CPVC
- Polypropylene and polyethylene
- Stainless steel, mild steel, and FRP-lined mild steel
- Nickel alloys
- Wide range of packing media including rings and saddles in various materials. Structured packing is also available.
- Complete instrumentation and electrical controls are available for stand alone operation or connection with a facility's centralized control or monitoring systems.
- Chemical treatment, including oxidation and neutralization, is available to increase absorption of gaseous pollutants. pH control available when applicable.
- Corrosion resistant AMCA rated fan on the inlet or outlet side of the scrubber.
- Corrosion resistant recirculating pumps for scrubber liquid recirculation.
- Non-plugging spray nozzles for wetting packing in a wide range of corrosion resistant materials. Special liquid distributors may also be used.
- Moisture eliminators with chevron, mist pad, or loose fill type designs.
Efficient Fume Scrubber Design
Monroe Environmental Packed Bed Scrubbers are custom designed to meet or exceed the specific removal efficiency required for each customer's application and process. Monroe can also provide a process simulation for difficult or unique scrubbing system applications. Monroe engineers will optimize the performance of each unit by thorough evaluation of relevant parameters.
Monroe will analyze:
- Contaminant solubility
- Vapor pressures
- Wash liquid flow rate
- Liquid to gas ratio
- Packing chamber height, diameter, and volume
- Packing media type and size
- Chemical additives
- pH control
- Precipitation of reaction products
- Multiple solution scrubbing
- Required scrubbing stages
- Pressure drop across packing
- Materials of construction
- Site requirements
Vertical Packed Tower Fume Scrubber
This vertical assembly is a counter-flow design with contaminated gas flowing upwards and recirculating liquid spraying downward into the packing media. Gaseous contaminants are absorbed by the liquid due to solubility levels or by chemical reaction. Counter-flow scrubbers have a smaller footprint and can have higher removal efficiency than a Monroe Horizontal Packed Bed Scrubber.
The vertical counter-flow design typically provides the best scrubbing efficiency of vapors and is the most common design found in most industries. The Monroe Vertical Packed Tower Scrubber is normally not used when solid particulate is in the air stream. Air flow capacity for a single shop fabricated tower can be up to 75,000 CFM.
Horizontal Packed Bed Fume Scrubber
This is a cross-flow design with scrubbing liquid flowing vertically downwards while the gas passes horizontally through the packing section. A Monroe Horizontal Packed Bed Scrubber is used when limited headroom is an issue at a customer's facility or when low profile is desired for roof-top applications. Multiple stages can be easily provided in one housing with separate sumps and pumps if required.
The cross-flow design is less susceptible to fouling for airstreams that may contain solid particulate. Air flow capacity for a single shop fabricated tower can be up to 75,000 CFM.
Chromic Acid Fume Scrubber — Multiple Stage Design
Emissions from chrome plating and chromic acid anodizing operations produce hexavalent chrome mist that cannot be effectively removed in a conventional packed tower scrubber. A modified type of horizontal scrubbing unit using specialized mesh filter pads with periodic flushing is required to meet regulatory guidelines for this contaminant. PVC construction is typical.
Typical Chrome Applications
- Anodizing Chrome
- Chrome Etching
- Chrome Manufacturing
- Chrome Stripping
- Hard Chrome Plating
Multiple scrubbing stages with different scrubbing solutions can be achieved by providing multiple scrubbing towers in series. These configurations can provide the highest removal efficiencies as well as multiple gas constituent removal. The diagram above includes three towers in series that could be used for H2S and ammonia removal.
Additional components that may be necessary to properly treat a given air stream can include:
- Quench towers
- Venturi Scrubbers with clarification tanks (for particulate removal)
- Carbon Adsorbers
- Fiberglass filters
- And many others