Gas Scrubber
Basics
- The industrial equivalent of an Air Purifier
- Can use one, or man steps/methods
- Typically used for filtration of chemicals, but often particles as well
- More dust focused units may be called Dust Collectors
Methods/Steps
Cyclonic Filtration
- Useful for removing particles such as Flue Ash
- Also used in dust evacuation systems in machine shops, and in vacuum cleaners
- Although not used for this in most industrial applications, the consumer vacuum cleaner company, Dyson, maketed a model with seccondary cyclones supposedly capable of getting near HEPA preformance
- This was acheived via a small neck, so small that semi-flexible portions were needed to allow clog preventing vibration
- Also there was a final HEPA filter, but this was supposedly more of a backup
- Most units in industry have only the "primary" cyclone for large to medium-small particles (essentiall no smaller than fine sawdust and large dust
- Cyclonic Vacuum Cleaners tend to also have a smaller seccondary cyclone (or muliple to increase flow), that is used for more fine particles
Electrostatic Precipitation
- Electrically Charges the air and/or particles, then uses a "negative" electrode to cause them to precipitate
Dry Catalysts
- This is used to change some chemical pollutants into either less harmful forms, or ordinary chemicals
- this is used on most moder cars
- More expensive, yet also more compact and simple
Settling Chamber
- Use space to allow particles to settle
- Most effective for in-line use is some sort of baffle chamber
- Mainly used for larger particles
Fluidized Bed
- Fluidized Bed Scrubbers uses catalysts
- Fluidized Bed Concentrator
- Uses either catalysts or carbon/activated carbon to react with and/or absorb pollutants from gas streams
- Complex yet effective
- Mainly used for gasous chemical pollutants
Thermal Methods
- This uses mainly heating or cooling, and sometimes the addition of catalyts or other chemicals
- Regenerative Thermal Oxidizer
Wet Scrubbers
- Essentially using liquids to absorb and/or react with particles and gasses in the gas stream
- Water can work for many applications such as remooving hydrogen sulphide (it turns to sulphuric acid, this was a product of historical gasworks, although most modern sulphuric acid comes from the Claus Process )
- Other liquids have their own applications
- For designs of these see Gas-Liquid Contactor
OSE Layouts
Heat Exchange/Heating/Cooling
- Hot Flue Gas etc may require pre cooling
- Heat Exchanger
- Heatsink
- Waterblock
Dust/Particles Removal
- Primany Cyclone
- Seccondary Cyclone(s)
- Electrostatic Precipitator
- Failsafe Filterbag/HEPA/ULPA Filter etc
Aerosol/Gas Chemical Pollutants
Concentrator Stage
- May not be needed in all applications
- Pressure Swing Absorbtion
- Fluidized Bed Concentrator
Filtration/Treatment Methods
