Textile mills are aware that of the total electricity units consumed per day towards compressed air, they are losing more than 30 per cent to compressed air leakage, says Ashok Sethuraman
Energy savings are a major issue in the functioning cycle of a textile mill. In the total electricity units consumed per day (UPD), the mill can reduce only around five to 10 per cent of UPD after energy audit and implementation. Compressed air leakage is a regular hidden cost in a mill. If not identified right away, it aggravates losses.
When a mill goes for modernisation, automated production demands more compressed air. So, instead of arresting existing air leakage, mills often buy more compressors to satisfy production demands. Ironically, leakage increases.
Why are there more losses in the compressed air system now?
The root cause is accumulation of water and dirt in compressed air pipe lines. This makes pneumatic fittings weak and leaky. A pneumatic fitting and component has a life. Beyond its life, leaks start. Soon, a drizzle turns into a shower.
The compressor post air cooler, refrigerated dryer and the zero air loss drain valves fixed in the air receivers at the compressor house, tail end and feed end receiver (Fig 1) are three sub-systems that have to work perfectly so that no water is trapped in the distribution and the load ends. More importantly, water ingress in the air actuation elements and solenoid valves in the machine will spoil their health.
Where is the loss happening in compressed air generation?
Compressed air generation is gets compromised if a compressor takes 5 to 10oC above the surrounding ambient temperature through choked air intake filters. This is two per cent KWH loss. Cool, dry compressors deliver more air output. So, try to give cool, dry air to the compressor air inlet as shown in Fig 5. Keep the load/unload settings to the minimum bar pressure just 0.7 bar, or 10 per cent above minimum required pressure demand from equipments.
Fix one pressure gauge just after the compressor and another gauge at the compressor house air delivery line/receiver. Fix a temperature gauge on the air receiver and keep its temperature 5oC above the ambient, which is a sign of unhealthy compressor package.