Water Treatment Chemicals
Steam Boilers, Cooling Towers,
Hot And Chilled Closed Systems
Fuel Oil Treatment
(Home of D.M Concentrate)
Condensate Treatment and
treatment of your plants steam
condensate is essential for two
protect the integrity of
your valuable equipment.
minimize the amount of
byproducts that are returned
to the boiler feedwater.
occurs in steam condensate
systems due to carbonic acid
attack and oxygen pitting.
Carbonic acid attack occurs due
to CO2, which is the
breakdown product of carbonate
alkalinity in the boiler,
condensing with water to form H2CO3.
This results in the
condensate piping, which usually
shows up first in leaks at
threaded sections. Oxygen
pitting occurs as steam
condenses and the vacuum created
pulls air into the system.
Because of the localized nature
of oxygen pitting it can cause
relatively quick failure in a
most common method of addressing
carbonic acid attack is through
the use of neutralizing amines.
These chemicals, such as
morpholine and cyclohexylamine
neutralize the carbon acid, and
increase the pH of the
condensate. Corrosion of mixed
metallurgy condensate systems is
minimized when the pH is
maintained between 8.8 and 9.2.
Due to high alkalinity in boiler
feedwater elevating the pH to
this level may not be
economical. In this case the pH
should be maintained at 8.3 or
higher, or a filming amine
applied. A filming amine, such
as octyldecylamine, provides a
non-wettable protective barrier
against both carbonic acid and
oxygen. When utilizing a filming
amine, the pH is usually
maintained between 6.5 and 7.5,
so a neutralizing amine may
still be required. Additionally,
filming amines can be difficult
to apply and generate fouling of
the system, particularly in
systems where they have not been
order to minimize oxygen pitting
one can utilize a filming amine
or a volatile oxygen scavenger
such as DEHA (diethylhydroxyamine.)
In the authorís opinion
utilizing DEHA provides better
results as it scavenges oxygen
and passivates the condensate
system, making it less
susceptible to corrosion. For a
comparison of DEHA vs.
on the treatment method chosen,
condensate monitoring can vary.
In all cases the following tests
should be performed.
and insoluble iron levels.
levels at various points in
your steam condensate
system. It is extremely
important that pH
measurements be made on
samples. If the sample is
taken hot, carbon dioxide
will flash, which results in
artificially high pH
a filming amine is utilized, the
residual should be measured. The
same is true if DEHA is used as
an oxygen scavenger. In the
latter case, a residual of 100
to 150 ppb is usually targeted.
Note that this may take time (as
much as 3 to 6 months) since
much of the DEHA will be
consumed passivating the system.
These are some general
guidelines. For specific
recommendations please contact
our staff through our Ask
the Experts functionality.