DESCRIPTION:
| TECHNICAL DATA: | |
| Type of Absorbent | Molecular Sieve Type 13 - X |
| Size of Molecular Sieve | 1.5 mm partite |
| Quantity of air handled | 250 m3/hr. |
| Heating Time | 3 1/2 hours |
| Cooling time | 5 hours |
| Changeover Time | 1 1/2 hours |
| Heating Inlet Temperature | Min. 250 Deg.C. To Max. 300 Deg.C. |
| Heating Outlet Temperature | Min. 150 Deg.C. To Max. 170 Deg.C. |
| Cooling Outlet Temperature | Min. 30 Deg.C. To Max. 50 Deg.C. |
| Main Air Inlet Temperature | Min. 8 Deg.C. to Max. 20 Deg.C. |
| Air Pressure | Min. 35 Kgs./cm2 to Max. 60 Kgs./cm2 |
| Max. Permissible Carbon dioxide in Atm. Air | 0.03% |
| Max. Moisture content | 50 % to 70 % |
| Allowable in Atm. Air relative humidity | At 15 Deg.C. |
| Heater capacity | 13.5 KW. |
| Heater voltage supply | 440V. |
| Heating individual ammeter reading | 55-60 amps. Each |
Molecular Battery:
Each vessel of the Molecular Battery is filled with Molecular
Sieve of 1.5 mm. Type 13-X. As the process air passes through
Molecular Sieve the Molecular Sieve will absorb water vapor
and CO2 from the air. After some 10 hours, the Molecular
Sieve becomes saturated, and it will have to be regenerated.
Molecular Sieve Driers:
If hot air at low pressure is passed through the saturated
Molecular Sieve, the Molecular Sieve will discharge the
CO2 and water vapor and is ready for use again. The absorbing
capacity of the Molecular Sieve drops rapidly if the process
air is warm. Therefore, ensure that the compressed air entering
into the Molecular Sieves below 15 Deg. C. And that the
Molecular Sieve is thoroughly cooled after regeneration,
before the process air is passed through it again.
REGENERATION:
The waste Nitrogen from the Cold Box is passed through an
Electrical Heater and then passed through the vessel to
be regenerated. The temperature at the inlet of the vessel
rises rapidly, while the outlet temperature wills rise very
slowly. If the outlet temperature reaches 170 Deg.C.(For
about one hour) the Molecular Sieve is regenerated. This
process is known as the heating cycle, which will take 2
/3 hours. At this stage, if the inlet temperature exceeds
300 Deg.C. The heater must be put off and put on again after
10 minutes. When the outlet put off, but the Cold Nitrogen
will continue to pass through the vessel cooling the Molecular
Sieve. This process is known as the cooling cycle which
will last about 4 hours. After cooling, the vessel is ready
for ,use when required for purifying the process air.
Oil vapor will destroy the Molecular Sieve and therefore ensure that the carbon filter is in good condition and the process air is as cool as possible, that maximum oil and moistures condenses out before the air enters the vessel.
While changing from one vessel to the other, pressurize
the vessel very slowly, by opening the valve A-7 or A-8.
It may take half a for the vessel to pressurize. If the
main valves are opened rapidly, the Molecular Sieve may
break up, due to high pressure air propelling the Molecular
sieve in the vessel.
When charging fresh Molecular sieve, lower the same slowly
through a pipe, so that it does not break on falling at
the bottom.
Most of the Plant operating problems are caused by the
carry over of CO2 into the Cold Box and its blocking the
Heat Exchangers. Satisfactory working of the Molecular Sieve
will avert all these problems. Therefore, maintain and operate
this equipment carefully.
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