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Air Compressor and Chilling Unit
The free saturated air is sucked from atmosphere through a highly efficient dry-type suctionfilter into the
first stage of the horizontal balanced opposed, lubricated reciprocating air compressor. Compresssed air is
chilled to 12 degree centigrade in achilling unit ata temperature of 12 degree centigrade to a moisture separator
where the condensed moisture gets removed before entering into Molecular Sieve Battery. Before sending the air
to MOLECULAR SIEVE BATTERY, air is passed through an OIL ABSORBER where air becomes oil free.
Purification of Air
Chilled air passes through the Molecular Sieve Battery consisting of Twin Tower packed with Molecular Sieves
to remove moisture and Carbon dioxide present in the air.
Molecular Sieve Battery operates on Twin Tower System, when one tower is under production the other tower is
regenerated by passing waste Nitrogen gas at 200 degC through a reactivation heater. After interval of 8 to
10 hours, the tower under production gets exhausted and regenerated by similar process before use and thus
the cycle continues. Any dust particles gets filtered in the DUST FILTER before air enters
the air seperation column.
Air Separation
Chilled, Oilfree and moisture free air enters into multi-pass HEAT EXCHANGER NO.I where it gets cooled to
(-80) degC by cold gained from outgoing waste Nitrogen and Oxygen.
A part of air this enters a multi-pass HEAT EXCHANGER NO. II or LIQUIFIER made of special Alloy tubes. This
air cools to (-170) degC before passing through an expansion valve. Due to joule Thompson Effect, after
the expansion valve. Due to joule Thompson Effect, after the expansion valve, air gets further cooled down
and gets liquified before entering into bottom column is known as RICH LIQUID.
THE RICH LIQUID in the BOTTOM COLUMN enters into feed tray of top column enters into feed tray of top column.
Similarly the liquid nitrogen called POOR LIQUID enters into top column as a reflux & it takes away the latest
heat of condensing Oxygen and gets vapourised whereas the liquid Oxygen flows down the trays of the
top column into the condenser passes through a sub-cooler to a liquid oxygen pump.
Cylinder Filling
Liquid oxygen pump pumps liquid oxygen through heat exchanger no. II and I, where liquidoOxygen gets gasified
before filling in cylinders in the filling manifold.
The pure bone dry oxygen gas at ambient temperature and high pressure is filled into oxygen cylinders through
manifold valves by means of the highly efficient reciprocating liquid oxygen pump.
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