| Treatment Options
- If you do not treat the water used by your
boiler, boiler shutdowns for expensive cleaning will be required to remove
the buildup of scale. If the corrosion is sufficient, you may also need
to replace your pipes.
- Boiler water carryover,
the contamination of the steam with boiler water solids, can occur if conditions
of excessively high suspended and dissolved solids are present in the water.
If the steam is used to sterilize, as in a hospital or food process plant,
the solids can cause critical problems by depositing out at the point where
the steam is used. In many industrial plants, steam is used directly on
the product produced, so that deposits carryover can cause the shutdown
of the plant, until the problem can be remedied. Maintaining the cycles
of concentration at a low level and using antifoam chemicals can prevent
this problem.
- You can combine chemical treatment with
the removal of solids known as blowdown. Softening agent
chemicals, which react with calcium and magnesium to produce a non-adherent,
very mobile and readily dispersed sludge, are added to the water to maintain
the water at "0" hardness. The non-adherent sludge is removed
by either manually wasting boiler water tothe drain (bottom blowdown) and/or
surface or skimmer blowdown. The water wasted is replaced with fresh water,
which further dilutes the amount of solids. The combination of this process
of dilution and adding chemicals keeps the system in control.
- Regulating blowdown. The two tests used
to regulate the frequency and volume of blowdown are chloride level and
specific conductance. These tests should be run daily by the boiler attendant,
who regulates blowdown to keep the solids within limits prescribed by your
Alken-Murray service representative. Since chloride does not react with
the chemicals in the water treatment, the cycles of concentration
can be calculated by testing this substance. Example: If the makeup
chlorides are 20 ppm and boiler water chlorides are 100 ppm, the boiler
is at 5 cycles of concentration. If makeup chlorides are at 30 ppm and
the boiler water is at 120 ppm, the boiler is at 4 cycles of concentration.
- The second test used for regulating blowdown
is specific conductance. A conductivity meter is used
to measure the conductivity of the "make up" water as compared
to the conductivity of the boiler water. The ratio of the two figures is
the "cycles of concentration". Example: If the makeup water
conductivity is 300 umhos and boiler water conductivity is 2100 umhos,
2100 ÷ 300 equals 7 cycles of concentration.
- Corrosion control is maintained by monitoring
pH and/or alkalinity. Test strips and meters are available to measure pH
and test kits are available from La Motte and CHEMetrics.
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