POLLUTANTS
Miscellaneous Gases
Phosgene
Used in chemical warfare, the effective and reliable removal of phosgene is absolutely
critical. Croll-Reynolds has designed and supplied a number of scrubbers for phosgene removal
for Chemical and Pharmaceutical Industry uses.
Phosgene is absorbed and effectively reacted with aqueous NaOH. The rate of mass transfer
tends to be relatively slow making it necessary to often utilize multiple deep counter
current packed beds to achieve the required performance. It is also essential to be
familiar with the way in which the reaction occurs between phosgene and NaOH. It is
necessary to maintain a certain excess of NaOH at all times
in solution in order to ensure that the phosgene is completely and properly reacted.
Croll-Reynolds is able to guarantee removal efficiencies for phosgene based upon empirical
data not theoretical calculations.
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Chlorine Dioxide
The key to proper design is to have available and to be aware of the data which relates
the absorption of ClO2 to the temperature of the scrubbing solution. ClO2 is one the most
sensitive compounds to solution temperature variation where aqueous absorption is concerned.
Counter current packed towers utilizing water once through or aqueous NaOH solution provide
high removal efficiencies for ClO2.
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Coal Tar Gases
The gas stream containing the coal tars are usually hot, moist, and difficult to handle due
to the "sticky" nature of the coal tars. The ability of these scrubbers to easily cool
gas streams, condense large amounts of water vapor (when present) and remove "tar-like"
contaminants with minimal maintenance are the reasons for their success in this application.
One key in the overall design is to stipulate a maximum operating temperature for the scrubbing
liquid in order to ensure sufficient cooling and condensation. Another key is to properly design
the mist eliminator. It must be efficient and yet not easily plugged. Jet Venturi Fume Scrubbers
or CR-5 Multi-Rod Deck Scrubbers are ideal for the effective removal of coal tar gases.
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