Fulton Classic ICX or FB-F Vertical Tubeless Boilers (Steam) Oil Fired - Manual (Page 23)

Both foaming and carry over cause
erratic boiler operation. When foam-
ing occurs an anti-foam should be
added or increased. The reason for
the high alkalinity should be deter-
mined. It may result from lack of
sufficient blow off. Pretreated
makeup water and condensate
should also be checked. Quite
often the source of alkalinity is an
overdose of alkaline internal water
treatment chemical.
pH: pH is a measure of the degree
of acid or base of solution. Normal
pH ranges of 6.5-9.0 will have little
influence on the corrosion rate of
cooling waters. If for some reason—
pollution, etc.—the pH is lowered
into the acid range, increased corro-
sion can be expected. The solution
lies in determining the cause of the
low pH and correcting that condi-
tion. A low pH can result in corrosion
of metals, while a high pH can result
in scale formation.
In order to control boilers and
equipment used for the external
treatment of make up water, it is
essential that reliable pH measure-
ments be made.
Phosphates: Ground or surface
waters seldom contain large
amounts of phosphates. If present,
it generally indicates fertilizer runoff
or pollution. Phosphate from raw
water can be the cause of scale
problems in open recirculating cool-
ing water systems after the water is
concentrated.
Chlorides: Chlorides are involved
in most cooling water corrosion
cells. Other factors being equal, it
can be assumed the higher the
chloride content, the more corrosive
the water. When pits or cracks occur
on stainless steel or other metals,
chlorides are always suspect.
High chloride levels can cause
severe corrosion. Corrosion from
chlorides can be controlled by
increasing the amount of corrosion
inhibitor or changing to a more
effective inhibitor.
Oil: Oil is not a natural constituent
of boiler water; still it can frequently
enter a system through leaks in a
condenser or other heat exchanger.
Oil can also enter a system through
the lubrication of steam driven recip-
rocating equipment. Whatever the
source, the presence of oil in boiler
water is undesirable. Oil can act as
a binder to form scale. In high heat-
transfer areas oil can carbonize and
further contribute to the formation of
scale.
Foaming is one indication of oil in
boiler water. Its presence can also
be confirmed by first shaking a bot-
tle containing boiler water. If oil is
present foam will result. To ensure
the foaming is being caused by oil,
add a small amount of powdered
activated carbon to the bottle con-
taining the boiler water and shake.
Little or no foam will appear if the
foaming is caused by oil.
Often oil in boiler water will originate
in the condensate. This contaminat-
ed condensate should be directed to
the sewer until the source of the oil
is determined and corrective steps
taken.
Silica: Silica in boiler deposits is
usually combined with other consti-
tutents. Silicates form a number of
different scale complexes with calci-
um, magnesium, aluminum, sodium,
and iron. Since there is at present
no effective dispersant for silicate
deposits, the scale problem can be
alleviated by maintaining close con-
trol of calcium, aluminum, and iron
as well as silica.
Iron (oxides): Iron in any of its
oxide or complex forms is undesir-
able in boiler water. It is very diffi-
cult to disperse so that it can be
removed the bottom blowoff lines.
Iron in its various forms can origi-
nate in the raw water makeup, con-
densate return water, or form direct-
ly in the boiler as a result of corro-
sion. Most iron oxide originates out-
side the boiler. It does not concen-
trate in the boiler and it tends to col-
lect in stagnant areas. If a boiler is
using raw water makeup, iron is
almost certain to be a major compo-
nent of developing scale.
Water Hardness: Water hardness
is the measure of calcium and mag-
nesium content as calcium carbon-
ate equivalents. Water hardness is
a primary source of scale in boiler
equipment.
Feedwater: Feedwater is the com-
bination of fresh makeup and return-
ing condensate that is pumped to
the boiler.
Condensate: Condensate is con-
densed steam that is normally low in
dissolved solids. Hence, it does not
contribute to the dissolved solid
content of the feedwater. In addi-
tion, condensate is very expensive
to waste. It's been chemically treat-
ed, heated, pumped, converted to
steam, and condensed. This costs
money and when condensate is
returned to the boiler, money is
saved.
Description/Instructions
15-O 4/00