This uploaded file is open for all fields of sphere

1. Compressed air supply
-- Dr Nisar Ahmed Arain
-- Assistant Professor
--Anesthesia/Critical care/ER

2. 2
© UNEP 2006
--Training Agenda and Compressor
--Introduction
--Types of Compressors
--Assesment of Compressors
and compressed air system
--Energy efficiency opportunities

3. Compressors:5to>
50,000hp
70– 90%ofcompressedairislost
--INTRODUCTION
--Significant Inefficiencies

4. INTRODUCTION
--BENEFITS OF MANAGED SYSTEM
--Electricity Savings: 20—50%
--Maintenance reduced
--Downtime decreased
--Production increased and
--Product quality improved

5. Introduction
Main Components in
Compressed Air System
--Intake Air Filters
--Inter Stage
--Coolers After Coolers
--Coolers
--Air Dryers
--Moisture drain traps
--Receivers

6. -Training Agenda Compressor
--Introduction
--Types of Compressors
--Assesment of Compressors
and compressed air systems
--Energy efficiency opportunities

7. Typeof
compressor
Positive
displacement
Dynamic
Reciprocating Rotary Centrifugal Axial
-Types of Compressors
-Two Basic Compressor Types

8. -Types of Compressors
-Reciprocating Compressor
--Used for air and refrigerant Compression
--Works like a bicycle Pump: Cylinder volume
reduces while pressure increases with
pulsating output
--Many configurations are available
--Single acting when using one side of the piston
and double acting when using both sides

9. -Types of Compressors
-ROTATORY COMPRESSORS
--Rotators instead of Pistons: continuous discharge
--Benefits of Low cost, Compact, low weight, easy
to maintain sizes between 30 to 200 hp
--TYPES
--Lobe Compressor
--Screw compressor
--Rotatory Vane/Slide Vane

10. -Types of Compressors
-Centrifugal Compressor
--Rotating impeller transfers energy
to move air continuous duty
--Designed oil free High Volume
applications >12,000 cfm

11. - Types of Compressors
-Comparison of Compressors
--Efficiency at full, partial and no load
--Noise level
--Size
--Oil Carry-over
--Vibration
--Maintenance
--Capacity
--Pressure

12. -Training Agenda Compressor
--Introduction
--Types of Compressors
--Assesment of Compressors and
compressed air system
--Energy efficiency opportunity

13. --Assesment of Compressors
--Capacity of a Compressor
--Capacity:-Full rated volume of flow of
compressed gas
--Actual Flow Rate:-Free air delivery(FAD)
--FAD:- reduces by ageing, Poor Maintenance
and Fouled heat exchanger and altitude
--Energy Loss:-Percentage deviation of FAD
Capacity

14. --Assesment of Compressors
--Simple Capacity Assesment Method
--Isolate compressor and receiver and close receiver outlet
--Empty the receiver and the pipeline from water
--Start the compressor and activate the stop watch
--Note time taken to attain the normal operational pressure
P2(In the receiver)from initial pressure P1
Calculate the capacity FAD
--P2=Final Pressure after filling
(Kg/cm2a)
--P1=Initial Pressure(Kg/cm2a)
after bleeding)
--P0=Atmospheric pressure
(Kg/cm2a)
--V=Storage volume in m3 which
includes receiver, after cooler
and delivery piping
--T=Time taken to build up
pressure to P2 in minutes

15. --Assesment of Compressors
--Compressor Efficiency
--Most practical specific power consumption
(KW/Volume flow rate)
--Other methods
a-Isothermia-1
b-Volumatric
c-Adiabatic
d-Mechenical

16. -Assesment of Compressors
-Compressor Efficiency
-Isothermal efficiency
--Isothermal efficiency=Actual measured input power
per Isothermal power
--Isothermal power(KW)=P1 x Q1 x logger / 36.7-P1=
Absolute intake pressure Kg Per cm2
--Q1=Free air delivered m3 per hr
--r=Pressure ratio P2/P1s

17. -Assesment of Compressors
-Compressor Efficiency
-Volumetric efficiency
--Volumetric efficiency=Free air
delivered/compressor displacement
--Compressor displacement=ΠxD2/4xL xS xχ x
n-D=Cylinderbore,meterL=Cylinderbore,
meterL=Cylinderstroke,meterS=compressor
speedrpmX =1forsingleactingand2for
doubleactingcylindersn=No.ofcylinders

18. -Assesment of Compressors
-Leaks
--consequences
--Energy waste: 20 – 30% of output
--Drop in the system pressure
--shorter equipment life
--Common leakage areas
--Couplings, hoses, tubes, fittings
--Pressure regulators
--Open condensate traps, shut off valve
--Pipe joints, disconnects, thread sealants

19. -Assesment of Compressors
-Leak Qualification Method
-Total Leakage Calculation
--Leakage (%) = [(Tx100)/(T +
t)]
--T=On load time(minutes)
t=off load time (Minutes)
--well maintained system: less than 10%
leakages

20. -Assesment of Compressors
-Quantifying leaks on the shop floor
--Shut off compressed air operated equipment's run compressor
to charge the system to set pressure of operation
--Note the time taken for “Load” and “Unload” cycles calculate
quantity of leakage (previous slide)
If Q is actual free air supplied during trial
(m3/min) then
system leakage (m3/minute) = Q X T (T + t)

21. ---Compressor capacity (m3/minute) = 35
---Cut in pressure, kg/cm2 = 6.8
---Cut out pressure, kg/cm2 = 7.5
---Load kW drawn = 188
kW
---Unload kW drawn = 54
kW
---Average ‘Load’ time =1.5
min
---Average ‘Unload’ time
-Assesment of Compressors
--EXAMPLE

22. -Raining Agenda: Compressor
--Introduction
--Types of compressors
--Assesment of compressors
and compressed air systems
--Energy efficiency
opportunities

23. -Energy Efficiency Opportunities
1-Location
significant influence on energy use
2-Elevation
Higher altitude = lower volumetric efficiency

24. -Energy Efficiency Opportunity
3. Air Intake
--Keep intake air free from contaminants, dust
or moist Keep intake air temperature low
--Every 4oC rise in inlet air Temperature = 1%
higher
energy consumption
--Keep ambient temperature low when an intake
air
filter is located at the compressor

25. -Energy Efficiency Opportunities
4. Pressure Drops in air Filter
--Install filter in cool location or draw air from
cool places
--Keep pressure drop across intake air filter
to a minimum
--Every 250 mm WC pressure drop =
2% higher energy consumption

26. -Energy Efficiency Opportunities
-5. Use Inter and After coolers
--Inlet air temperature rises at each stage of
multistage machine
--Inter coolers: heat exchangers that remove heat
between stages
--After coolers: reduce air temperature after final
stage
--Use water at low temperature: reduce power

27. -Energy Efficiency Opportunities
6.Pressure Settings
-Higher Pressure
a-More power by compressors
b-Lower volumetric efficiency
-Operating above operating pressures
a-Waste of energy
b-Excessive wear

28. Energy Efficiency Opportunities
6.Pressure setting cont.
--a-Reducing delivery pressure operating a compressor
at 120 PSIG instead of 100 PSIG: 10% less energy
and reduced leakage rate
--b-Compressor modulation by optimum pressure
settings, Applicable when different compressors
connected Segregating high/Low pressure
requirements
Pressure reducing valves no longer needed

29. -Energy Efficiency Opportunities
6-Pressure Settings cont.
--Design for minimum pressure drop in the distribution line
--Pressure drop: reduction in air pressure from the
compressor discharge to the point of use
--Pressure drop less then 10%
--Pressure drop caused by
a-corrosion
b-Inadequate sized piping couplings hoses
c-checked filter elements inadequate sized

30. 3
0
© UNEP 2006
-- Energy Efficiency Opportunities
--6-Pressure settings cont.
--Design for minimum pressure drop in the
distribution line
--Different pipe size
--Typical pressure drop in compressed air line

31. -Energy Efficiency Opportunities
7-Minimizing Leakage
--Use ultrasonic acoustic detector
tighten joints and connections
replace faulty equipment
8-Condensate Removal
--Condensate formed as after cooler
reduces discharge air temperature
--Install condensate separator trap to
remove condensate

32. -- Energy Efficiency Opportunities
9-Controlled Usage
--Do not use for low pressure applications
agitation, combustion air, Pneumatic
conveying use blowers instead
10-Compressor Controls
--Automatically terns off compressor when
not needed

33. Energy Efficiency Opportunities
9-Maintainence Practices
--Lubrication:- checked regularly
--Air Filters:-Replaced regularly
--Condensate Traps:-Ensure drainage
--Air dryers:-Inspect and replace filters

34. THANK YOU