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- Product should be stored between
85° to 100°F (29° to 38°C).
- Over time, precipitation of calcium
and magnesium hydroxide, carbonates and oxalates will
occur. A 2-4 year out-of-service tank cleaning schedule is
recommended.
- Tank
discharge should be elevated at least 1 ft (30 cm)
above the tank bottom to minimize entrainment of sediment.
- A second
tank discharge and a manway at the bottom of the tank
for cleaning is recommended.
- Tank
inlet should be above the highest anticipated tank level
with an inlet dip pipe, which extends below the lowest
anticipated tank level to prevent splashing of the
caustic soda solution.
- Splashing or freefalling liquid,
leaking pump suction gaskets, etc. will enhance additional
carbon dioxide absorption resulting in the formation of
insoluble sodium carbonate. These situations should be
avoided.
- Tank
inlet should have a syphon break and be opposite the
discharge line.
- A 100% containment dike should be
built around the storage tank.
- It is recommended that an all
Alloy-20 material of construction plug valve be used as the
first valve on the tank.
- A continuous tank level measurement
device should be installed. High level and overf
- Redundant temperature sensors
should be installed for temperature control.
- High temperature alarms should be
included.
- Tanks
should be vented to atmosphere and the vent line routed to
within 3-feet (0.9 meter) of grade. The vent line
should include a syphon break.
- Tanks and pipes should be insulated
and traced to prevent the caustic soda solution from
freezing.
- The entire piping system should be
free draining.
- Electric heat tracing is
recommended and preferred over steam tracing.
- Aluminum, magnesium, zinc,
tin, chromium, bronze, brass, copper, and tantalum are
incompatible with caustic soda solution and
must not
be used for wetted parts used in equipment such as tanks,
pumps, piping, instrumentation, etc.
- Galvanized (zinc coated)
materials should not
be used in caustic soda solution storage and process areas.
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