Training Manual on Energy Efficiency - APO Asian Productivity ...

<strong>Training</strong> <strong>Manual</strong> on Energy Efficiency for Small and Medium Enterprises
9.3 COMPRESSED AIR SYSTEM COMPONENTS
Compressed air systems consist of the following major components: intake
air filters, inter-stage coolers, after-coolers, air dryers, moisture drain traps,
receivers, piping network, filters, regulators, and lubricators.
Intake air filters prevent dust from entering the compressor. Dust causes
sticking valves, scoured cylinders, excessive wear, etc.
Inter-stage coolers reduce the temperature of the air before it enters the
next stage to reduce the work of compression and increase efficiency. They are
normally water-cooled.
After-coolers work to remove the moisture in the air by reducing the
temperature in a water-cooled heat exchanger.
Air dryers:
The traces of moisture remaining after the application of after-coolers are
removed using air dryers, as air for instruments and pneumatic equipment
has to be free of any moisture. The moisture is removed using adsorbents
like silica gel/activated carbon, refrigerant dryers, or heat from compression
dryers.
Table 9-1 Adsorbents used to dry air
Moisture drain traps:
Type Dew Point ( º C)
Desiccant Regeneratives
(Air purging)
Desiccant Regeneratives
(Blowing)
Desiccant Regeneratives
(Heat of compression)
Refrigerants
(Drying)
Moisture drain traps are used for removal of moisture in the compressed air.
These traps resemble steam traps. The types of traps used include manual
drain cocks, timer-based automatic drain valves, etc.
Receivers:
Air receivers are provided for storage and smoothening of pulsating air output,
reducing variations in pressure of air from the compressor.
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Power
Consumption
(kW/1000 m3/hr)
–40 20.7
–40 18
–40 12
–20 2.9