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Molecular Sieve Driers for Air Separation Plants, Oxygen
Plants, Nitrogen Plants, Acetylene Plants The
drier valve seats should be in prefect condition and if the
air passes through valve seat both production of plant
and regeneration of driers will-be affected.
IMPORTANT Equipment for Molecular Sieve
Driers for Air Separation Plant, Oxygen Plant, Nitrogen Plant,
Acetylene Plant:
The Heater should immediately be shut down either in case
of Plant shut down or Expansion Engine shut down. Otherwise,
water and water vapor will be drawn from evaporation cooler
by the Blower and will flood the Heater and the drier with
water. DRIER CHANGE OVER:
When cooling is complete, the regenerated drier is to be lined
up, as the other drier would have become saturated by now.
First, the Nitrogen blower is to be switched off.
The Nitrogen valves of regenerated drier are to be
closed. Then the regenerated drier will first be pressurized
through pressurizing valve. The pressuring shouldn't, be sudden
and hence not through main air inlet valve. The Molecular
Sieve pallets will get disintegrated soon if pressurizing
and depressurizing is sudden. After pressurizing open air
inlet valve completely. Open air outlet valve gradually, watching
the outlet air temperature. This temperature will
initially go up and thereafter will cool--down. Then open
the outlet valve completely. Start closing the outlet valve
of the drier on line, taking care of common air outlet temperature.
Then close air outlet and inlet valves of drier, which was
on line tightly.
Depressurize the drier by depressurizing valve. The open
the Nitrogen valves of the drier to be regenerated. Start
the Nitrogen Blower. Check flow of the gas at the regeneration
Nitrogen vent. The switch on the drier heater for starting
heating cycle of drier. Check for proper performance of drier
heater.
DRIER CHANGEOVER (In Short):
Imagine No.1 drier is ready after regeneration. (In case of
No.2 Drier adjusts the valves given in brackets.)
1. Stop Heater.
2. Close N-5 and N-7. (N-6 & N-8)
3. Close A-9 and open A-7 and A-8
4. Watch P-5 to increase gradually for Y2
an hour. (P-6)
5. When P-5 and P-6 are almost equal, open
A-3. (A-4)
6. Close A-:7, A-8 and A-9.
7. Open A-5 slowly watch T-4. (A-6)
8. After 15 minutes on A-5 fully and start
Closing A-6 slowly. (A-6, A-5)
9. After 15 minutes close A-6 and A-4 Completely.
(A-5, A-3)
10. Open A-9 and A-8 (A-9, A-7)
11. P-6 will come down (P-5)
12. When P-6 reads minimum, open N-6 &
N-8 (P-5, N-5, N-7) Start heater and check the amperes in
each phase To ensure that no heater is burnt.
All Starting Drier Heater and watch T-13.
REPLACEMENT OF MOLECULAR SIEVE FOR NITROGEN ACETYLENE
OXYGEN PLANT:
Molecular Sieve is to be replaced if:
It becomes powder.
If it gets contaminated by oil; or
If it looses its adsorption capacity:
The above will be known by frequent checking of Cold Box
Equipments.
To change Molecular Sieve, open the top and bottom flanges
of drier vessels. Remove the filter at the bottom. Collect
the old Molecular Sieve, which will fall down. Clean the filters
blow the drier vessel.
Fit the bottom filter. Charge about 3 kgs. of Alumina. Then
charges Molecular Sieve Type 13X, size 1.5 mm., size 1.5 mm.
about 90 kegs. The Molecular Sieve should be sieved and be
free of all smaller size particles. It is better to charge
through a long funnel so that Molecular Sieve does not fall
with a force and break. Charging is normally done by hand.
When leve1 of Molecular Sieve is just at the brim of dished
end of prier vessel, stop charging. Then fill up the doomed
portion with alumina. Fit the top filter after cleaning.
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