compressed air system...
TRANSCRIPT
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COMPRESSED AIR SYSTEM
OPTIMIZATION
EXPERT TRAINING
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1
Introduction toIntroduction to Compressed Air
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1. Introduction to Compressed Air Systems1. Introduction to Compressed Air Systems
• Compressed air has 3 primary uses– Power
• As an energy source to perform work
– Process
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Process• Air becomes part of a process
– Control • To stop, start or regulate the
operation of a machine
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1. Introduction to Compressed Air Systems1. Introduction to Compressed Air Systems
• A compressed air system includes both the supply side components and the demand
3
side components.
1. Introduction to Compressed Air Systems1. Introduction to Compressed Air Systems
• Old Management Technique– Plant production is #1
priority
• New Management Technique– Plant productivity is the #1
prioritypriority– Plant compressed air
system must always be maintained
– Over supply of compressed air is acceptable, under supply is not acceptableMi i t
priority– The plant air demand must
always be supplied– The compressed air system
must be in balance with demand. Both over supply and under supply are unacceptable
– Compressed air pressure t b t bl P
4
– Minimum pressure must be maintained. Higher pressure is acceptable
must be stable. Pressures higher than required are unacceptable as are pressures lower than required.
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3
Com
pres
sed
Air
Sys
tem
Opt
imis
atio
nD
efin
ed
Ther
e ar
e th
ree
basi
c w
ays
to o
ptim
ise
the
cons
umpt
ion
of a
co
mpr
esse
d ai
r sys
tem
:
1.P
rodu
ce c
ompr
esse
d ai
r mor
e ef
ficie
ntly
2.C
onsu
me
less
com
pres
sed
air
3.U
tilis
eth
e he
at o
f com
pres
sion
Sou
rce:
AS
ME
EA
-4
5
Com
pres
sed
Air
Sys
tem
Effi
cien
cy
Fact
:Com
pres
sed
air i
s an
inef
ficie
ntso
urce
of
ener
gy
and
shou
ld b
e us
ed w
isel
y.
Con
side
r thi
s:
•An
air
mot
or w
ith 0
,68
kW s
haft
outp
ut c
onsu
mes
50
m3 /h
r
6
•An
air
com
pres
sor c
onsu
mes
abo
ut 5
.6 k
W to
pro
duce
50
m3 /h
r at 7
bar
, or 8
tim
es a
s m
uch!
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8
Compressed Air System Efficiency
2
4
6
hp
PowerLosses onSupply and
DemandSides
(includingheat of
compression
0
losses)
Input Powerto Electric
Motor
Shaft PowerRequired byCompressor
PowerLosses andUseful Work
Useful Work
Source: Compressed Air Challenge
Compressed Air System Cost
Compressed air power is costly
• The 0,68 kW compressed air motor shaft output costs RM 16 000 per year at 8 760 hours operation.
• An electric motor with a similar shaft output would consume about 0,85 kW and cost RM 2 430 per year to operate.
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Compressed Air System Costs
System losses further increase the costs:
Typically 35 to 45% of compressed air is wasted to leakage andTypically 35 to 45% of compressed air is wasted to leakage and artificial demand before it gets to the user. And 10%+ may be wasted through inappropriate uses.
Artificial Demand – 10-15%
Inappropriate Uses – 5-10%
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Production – 50%
pp pLeaks – 25-30%
Compressed Air System Costs
System losses further increase the costs:
Pressure differentials typically reduce end use pressure by 1Pressure differentials typically reduce end use pressure by 1 or 2 bar forcing discharge pressures higher. Compressor power increases 6 to 7% per unit output for every bar increase.
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Compressed Air System Costs
System losses further increase the costs:
Air compressors often do not run at full efficiency due to poor control and lack of storage receiver capacity
60
80
100
120nt
kW
Inpu
t
11
0
20
40
0 20 40 60 80 100 120
Per cent Capacity
Per c
en
The Systems Approach
Application of a systems approach to a compressed air system assessment and resulting energy measures directs the focus towardsassessment and resulting energy measures directs the focus towards total system performance rather than individual component efficiency
• Understand compressed air point of use as it supports critical plant production functions
• Correct existing poor performing applications and those that upset system operationEli i t t f l ti l k tifi i l d d d
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• Eliminate wasteful practices, leaks, artificial demand, and inappropriate use
• Create and maintain an energy balance between supply and demand• Optimize compressed air energy storage and air compressor control
Source: ASME EA-4
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Life Cycle Costs
Typically over 75% of the lifetime costs of compressed air are energy relatedenergy related
Source: Compressed Air Challenge
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Source: Compressed Air Challenge
Based on 30 cen per kWh blended rate 55 kW fully loaded compressor at 4200 hours over ten years.
Typical Compressor Operating Cost
Item: Typical 160 kW air cooled screw compressorDuty: Full load at 7 5 bar 4 200 hours per yearDuty: Full load at 7.5 bar, 4 200 hours per yearRate: 30 cen per kWh blended
Power at full load: 182.5 kWFlow: 505 l/sec Specific Power: 36.1 kW/ 100l/s
Energy Cost = kW x hours x rate
Energy Cost = RM 229 950 per yearPurchase Price = RM 189 540
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Comparing Energy Usage and Efficiency
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Three 160 kW compressed air systems are being evaluated in
Compressed Air System Comparisons
an existing plant :
1. Existing fixed speed air cooled load/unload compressor, standard refrigerated dryer, standard filter and small receiver
2 A new fixed speed load/unload compressor new refrigerated2. A new fixed speed load/unload compressor, new refrigerated dryer, oversized filter and large receiver
3. A VSD compressor, cycling refrigerated dryer, oversized filter and medium receiver
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Compressed Air System Comparisons
Air cooled compressor, 8 bar 8 760 hour operation, peak flow 330 l/s average flow 175 l/s cost 0 3 cen per kWh330 l/s, average flow 175 l/s , cost 0,3 cen per kWh
Option 1 – Existing unit – Base Case
Ave Compressor Power = 134,5 kW
Dryer Power = 6,0 kW
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Total Energy = 1 230 780 kWh
Specific Power = 80,3 kW/100 l/s
Electrical Cost = RM 369 200
Compressed Air System ComparisonsAir cooled compressor, 7 bar 8 760 hour operation, peak flow 268 l/s, average flow 133 l /s, cost 0,3 cen per kWhg p
Option 2 – New more efficient load/unload , larger storage, lower pressure, cycling refrigerated dryer, leak reduction
Ave Compressor Power = 85,1 kWDryer Power = 1,7 kW
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Total Energy = 760 400Specific Power = 65,3 kW/100 l/sElectrical Cost = RM 228 100Saved = RM 141 100 or 38%Project Cost = RM 400 000
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Compressed Air System ComparisonsAir cooled compressor, 7 bar 8 760 hour operation, peak flow 268 l/s, average flow 133 l /s, cost 0,3 cen per kWhg p
Option 3 – New VSD unit, medium storage, lower pressure, cycling refrigerated dryer, leak reduction
Ave Compressor Power = 46,0 kWDryer Power = 1,7 kW
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Total Energy = 417 850 kWhSpecific Power = 35.9 kW/100 l/sCost = RM 125 400Saved = RM 243 800 or 66%Project Cost = RM 485 000
Compressed Air System Payback
Option Project Savings PaybackOption Project Cost
Savings Payback
O1 - Base 0 0 0
O2 - New load/unload RM 400 000 RM 141 100 2.8
O3 - New VSD RM 485 000 RM 243 800 2.0
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Compressed Air System Incremental Payback
Option Project Savings PaybackOption Project Incremental Cost
Savings Payback Years
O1 - Base RM 235 000 0 0
O2 - New load/unload RM 165 000 RM 141 100 1.2
O3 - New VSD RM 250 000 RM 243 800 1.0
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Artificial Demand• If the required• If the required
pressure is 5.5 bar • Operating at 7 bar
creates 2.8 m3/min of artificial demand
• 20% of the air that is• 20% of the air that is supplied to the system is wasted.
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1. Introduction to Compressed Air Systems1. Introduction to Compressed Air Systems
Finding leaks• soap connections• locate source of noise• ultra-sound device
Example:hole diameter: 3 mm air loss: 0.5 m3/min (6 bar gauge)0 5 m3/min x 60 min/h = 30 m3/h
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0.5 m /min x 60 min/h = 30 m /h 30 m3/h x 8000 h/year = 240,000 m3/year
240,000 m3/year x cost/m3 = ????
1. Introduction to Compressed Air Systems1. Introduction to Compressed Air Systems
Leakage losses
At RM 0.30/kWh, a 6 mm leak costs over RM 35,478 /year in power plus additional service on the compressed i i t
Hole diameter
1 mm2 mm4 mm6 mm
Air consumptionat 6 bar (g)
m3/min0.050.210.832 12
Loss kW
0.31.35.2
13 5
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air equipment.
Class exercise: Calculate the cost over 4,000 hours.
6 mm 2.12 13.5
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1. Introduction to Compressed Air Systems1. Introduction to Compressed Air Systems
Leakage losses
Hole diameter
1 mm2 mm4 mm6 mm
Air consumptionat 6 bar (g)
m3/min0.050.210.832 12
Loss kW
0.31.35.2
13 5
At RM 0.30/kWh, a 6 mm leak costs over RM 35,478 /year in power plus additional service on the compressed i i t
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6 mm 2.12 13.5 air equipment.
Class exercise: Calculate the cost over 4,000 hours.13.5 kW x 4,000 x 0.30 = RM 16,200Question: How much if at 7 bar?
1. Introduction to Compressed Air Systems1. Introduction to Compressed Air Systems
Leakage losses
Hole diameter
1 mm2 mm4 mm6 mm
Air consumptionat 6 bar (g)
m3/min0.050.210.832 12
Loss kW
0.31.35.2
13 5
At RM 0.30/kWh, a 6 mm leak costs over RM 35,478 /year in power plus additional service on the compressed i i t
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6 mm 2.12 13.5 air equipment.
Class exercise: Calculate the cost over 4,000 hours.13.5 kW x 1.06 x 4,000 x 0.30 = RM 17,170Question: If this leak was repaired how much would be saved?
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1. Introduction to Compressed Air Systems1. Introduction to Compressed Air SystemsMeasuring leakage lossesby exhausting an air receiver
Leakage volume
Feed pipeshut offVR x ( pI - pF )
VL = T
VL = Leakage volumeV = Receiver volume
g(tools not in use!)
x 1.25
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VR = Receiver volumePI = Initial receiver
pressurePF = Final receiver
pressureT = Measuring period
Example:VR = 500 litrespI = 9 bargpF = 4.5 bargT = 30 sec
VL =500 l x ( 9 – 4.5 )
30 sec= 75 x 1.25 = 94 l/s
Leakage losses in the compressed air system: 94 l/s
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1. Introduction to Compressed Air Systems1. Introduction to Compressed Air Systems
Measuring leak lossesby measuring loaded time of the compressor with end users shut off
Pressure gauge reading(bar(g))
T
VL = Leakage volume in m3/minVC = Compressor volumetric flow rate in m3/mint = Time units during which the compressor
ran on loadT = Total time of the measurement procedure
Example:Volumetric compressor flow rate V = 3 m3/minCompressor time on load t =t1+t2+t3+t4+t5 = 120 sec3
4
5
6
7
8
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Time
Compressor time on load t t1+t2+t3+t4+t5 120 secTotal measurement time T = 600 sec
3 x 120600
= 0.6 m3/min = 20%1
2
3
c
1. Introduction to Compressed Air Systems1. Introduction to Compressed Air SystemsLeak measurement of the consumers
In factories where a large number of air tools, machines and
Using the two methods described previously, two measurements are carried out:
In factories where a large number of air tools, machines andequipment are used, hose connectors and valves often causeconsiderable leak losses.
A B
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The difference between A and B represents the losses in the pneumatic tools, etc. and their fittings.
Tools, machines and equipmentare connected for normal operation(total leakage)
The shut-off valves upstream of the connectors of the consumers are closed (air distribution leakage)
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Key Learning Points• Compressed air is a necessary utility for industrial p y y
plants.• For some production uses compressed is a process
variable.• Many systems waste 50% of more of the compressed
air that is consumed.• System management must focus on productivity rather
than traditional goalsthan traditional goals.• The Systems Approach is an integrated approach, not
component efficiency.• Generating compressed air is an inefficient energy
conversion.
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Key Learning Points• Using air only when other alternatives are not Us g a o y e ot e a te at es a e ot
available.• Eliminating inappropriate uses of compressed air.• Reducing delivered pressure to the system
eliminates Artificial Demand.• Reducing the amount of leakage loss in the system.• Minimize Irrecoverable Pressure Loss.Minimize Irrecoverable Pressure Loss.• Operating compressed air systems at the lowest
practical pressure.• Optimize compressor control with a properly
implemented control strategy.
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For more information:Wayne PerryTechnical DirectorKaeser CompressorsP O Box 946
Tom TarantoPresidentData Power Services8417 Oswego Road PMB 236
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P.O Box 946Fredericksburg, VA 22404USA540 898 [email protected]
8417 Oswego Road PMB-236Baldwinsville, NY 13027USA315 635 [email protected]
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2. Understanding 2. Understanding ggCompressed AirCompressed Air
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2. Understanding Compressed Air2. Understanding Compressed Air
Power stationgrid system
transformeruser
What is compressed air?Compressed air is ...
... compressed atmospheric air
... a mixture of gases
... compressible
... an energy carrier
userair main
air treatmentAir center
air?
2
Proportional relationship between pressure, temperature and volume: still valid:
userair treatment
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2. Understanding Compressed Air2. Understanding Compressed Air
Basic units m = Meter
s Second
kg = Kilogram
A = Amperes = Second
K = Kelvin
A = Ampere
mol = Molar mass
Derived units N = Newton Pa = Pascal
3
N = Newton
bar = Bar
J = Joule
C = Celsius
Pa = Pascal
= Ohm
W = Watt
Hz = Hertz
2. Understanding Compressed Air2. Understanding Compressed Air
Physical laws
COMPRESSED AIR is atmospheric air under pressureCOMPRESSED AIR is atmospheric air under pressure. That means energy is stored in the air. When the compressed air expands againthis energy is released as WORK.
pressure (energy)
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EXPANSION
WORK
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2. Understanding Compressed Air2. Understanding Compressed Air
Components of air
oxygen21%
other gasses1%
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nitrogen78%
2. Understanding Compressed Air2. Understanding Compressed Air
Atmospheric pressure...
...is generated by the weightof the atmosphere. It is dependent on the DENSITYof the air and the height:
The normal atmospheric pressure at sea level is 1.013 bar (760 mmHg (Torr))
6
( g ( ))
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2. Understanding Compressed Air2. Understanding Compressed Air
Absolute pressure ...... is the pressure measured
from absolute zero
Gauge pressure ...
... is the practical reference pressure
atmospheric pressurepamb
from absolute zero.It is used for all theoreticalcalculations and is required invacuum and blower applications.
and is based on atmospheric pressure.
absolute pressure
7
vacuum100%
0%
absolute pressure
gauge pressurevacuum
(g) (g) (g) (g)Pg
2. Understanding Compressed Air2. Understanding Compressed Air
Generally:Equivalents
105 Pa = 1 bar
1 MP 10 bF (F)
Definition of pressures
1 MPa = 10 bar
Gauge pressure1 bar = 14.5 psi(g)
1 hPa = 0.001 bar
1 bar = 10197 mmWC
1 bar = 750.062 Torr
Dimensions:
1 Pascal (Pa) =1 Newton (N)
1 m² (A)
Pressure (p) = Force (F)Area (A)
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A = 1 m2
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2. Understanding Compressed Air2. Understanding Compressed Air
ambient air pressure1 bar (a)
Volume
7 m³ atmospheric
air volume
working pressure7 bar (a) = 6 bar (g)
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1 working m³
2. Understanding Compressed Air2. Understanding Compressed Air
Expansion:Volume
Ambient air pressure p0, V0
Working pressure7 bar (a)= 6 bar (g)Working
pressurep1, V1
10
The volume of atmospheric air decreases at an inverse ratio to the respective absolute pressures (at constant temperature,without taking humidity into account) 1
0
0
1
pp
VV
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2. Understanding Compressed Air2. Understanding Compressed Air
Temperature DensityRelativehumidityPressure
Definition of volumes
Volume accordingto DIN 1343(normal physical state)
Volume accordingto DIN/ISO 2533
Volume related
humidity
0°C =273.15K
1.01325bar 0%
1.294kg/m³
15°C =288.15K
1.01325bar 0%
1.225kg/m³
atmospheric atmospheric atmospheric
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Volume related to atmosphere (normal state)
Volume related to operating state
atmospherictemperature
atmosphericpressure
atmospherichumidity variable
working temperature
workingpressure
variablevariable
2. Understanding Compressed Air2. Understanding Compressed Air
Conversion of normal volume to volume according to DIN 1343
VN = Normal volume to DIN 1343VI = Volume at inlet conditionsTN = Temperature to DIN 1343, TN = 273.15KT = Maximum temperature at the installation in K
VI x TN x (pI - (Hrel x pD))pN x TI
VN =
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TI = Maximum temperature at the installation in KpN = Air pressure to DIN 1343, pN = 1.01325 barpI = Lowest air pressure at the installation in barHrel = Maximum relative humidity in the air at the installationpD = Saturation pressure of the water vapor contained in the air
in bar, dependent on the temperature of the air
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2. Understanding Compressed Air2. Understanding Compressed Air
Extract from the table for the saturation pressure of water vapour at saturation
-10 0.00260-9 0.00280-8 0.00310-7 0.00340-6 0.00370-5 0.00400-4 0.00440-3 0.00480-2 0.00520-1 0.005600 0 00610
10 0.012311 0.013112 0.014013 0.015014 0.016015 0.017016 0.018217 0.018418 0.020619 0.022020 0 0234
30 0.042431 0.044932 0.047333 0.050334 0.053235 0.056236 0.059437 0.062738 0.066239 0.069940 0.0738
Saturation pressurepD (bar) at airtemperature t (° C)
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0 0.006101 0.006402 0.007103 0.007404 0.008105 0.008706 0.009407 0.010008 0.010709 0.01150
20 0.023421 0.024522 0.026423 0.028124 0.029825 0.031726 0.033627 0.035628 0.037829 0.0400
41 0.077842 0.082043 0.086444 0.091045 0.096846 0.100947 0.106148 0.111649 0.117450 0.1234
2. Understanding Compressed Air2. Understanding Compressed Air
Gas laws – Boyle’s Law
If the volume is reduced under constant temperature, the pressure increases.
Gas laws Boyle s LawIsotherms (constant temperature)
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Heat dissipation
1100 VPVP
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2. Understanding Compressed Air2. Understanding Compressed Air
Isotherms (constant temperature)
Heat dissipation
p
p1T0 = T1
1
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V
p0
V1 V0dV
0
2. Understanding Compressed Air2. Understanding Compressed Air
Gas laws – Charles’ LawIsobars ( constant pressure )If heat is applied under constant pressure,The air volume behaves directly proportionalto its absolute temperature.
Isobars ( constant pressure )
00 TV
16
Application of heat11 TV
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2. Understanding Compressed Air2. Understanding Compressed Air
Isobars (constant pressure)
p
p0= p10 1
T
p0 = p1Application of heat
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VV1V0 dV
T1
T0
2. Understanding Compressed Air2. Understanding Compressed Air
A li ti f h t
Gas laws – Amonton’s LawIsochors (constant volume)
If heat is applied with constant volume, the pressure behaves directly proportional to the absolute temperature.
Application of heatIsochors (constant volume)
00 TP
18
11 TP
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2. Understanding Compressed Air2. Understanding Compressed Air
Isochors (constant volume)
p
p1
V0=V1
1
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p0
V
T0
T1
0
Application of heatV0=V1
2. Understanding Compressed Air2. Understanding Compressed Air
If th l i d d d h t t b di i t dHeat insulation
Adiabatic or Isentropic(no heat transfer)
If the volume is reduced and heat cannot be dissipated,temperature increases with the pressure
p
p1 1
p p
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Vp0
V1 V0
T1T0
dV
0
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2. Understanding Compressed Air2. Understanding Compressed Air
Gas law relating to a closed system:Gas equation
p0 x V0 p1 x V1T0 T1
= = R = constant
p = pressure (bar (absolute))V = volume (m3)
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T = temperature (K)R = special gas constants
e.g. R = 28.96 = 289.6
for dry air
bar·m³K
Jkg·K
2. Understanding Compressed Air2. Understanding Compressed Air
Flow velocity in air lines
• A1 v2
A1
v1
A2v2
valid is:
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V = flow volumev = velocityA = pipe sectional area
V = A1 x v1 = A2 x v2 A1A2
v2v1=
•
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2. Understanding Compressed Air2. Understanding Compressed Air
Flow profilepipe wall
border layer
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flow velocity
2. Understanding Compressed Air2. Understanding Compressed Air
Flow typesWe differentiate between:laminar (even) and turbulent (swirling) flow
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2. Understanding Compressed Air2. Understanding Compressed Air
Straight-line graphfor determining inside
Pipe length in m
Free air deliverym³/h m³/min
Insidepipe dia. (mm)
Pressure lossesbar
for determining insidepipe diameter (steps 1 to 8)
1
2
3
4
5
678
m³/h - m³/min
System-pressurebar (g)
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2. Understanding Compressed Air2. Understanding Compressed Air
Compressed air in motion
bar)
Pressure lossis dependent on:
sectional areavelocitypipe length
Pre
ssur
e (b
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internal surface area of the pipelength (m)
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2. Understanding Compressed Air2. Understanding Compressed Air
PerformancePressure drop ...
... is caused by: Working press.bar (g) % kW
6.0 100 3.0
5.5 86 2.6
5.0 74 2.2
•high flow velocities •turbulence•internal friction (molecules)•friction on the pipe walls
Pressure drop lowers the performanceof the consumers, increasesthe cost of compressed air generation
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4.5 62 1.9
4.0 52 1.6
Performance loss caused by pressure drop
the cost of compressed air generationand thus production too!
2. Understanding Compressed Air2. Understanding Compressed Air
Minimum diameters of pipes
FADm3/min
working pressure 7.5 bar (g)
length of pipelineup to 50 m up to 100 m up to 200 m over 200 m
see straight-line graph
up to 12.5up to 15,0up to 17.5up to 20.0
2 1/2"2 1/2"2 1/2"
3"
2 1/2"2 1/2"
3"3"
3"3"
DN100DN100
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pup to 25.0up to 30.0
3"3"
DN100DN100
DN100DN100
up to 40.0 DN100 DN100 DN 125
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2. Understanding Compressed Air2. Understanding Compressed Air
Flow resistance of fittingsexpressed in equivalent pipe lengths
fitting example
6 10 15 25 30 50 60
equivalent pipe length in m
pipe inside diameter in mm25 40 50 80 100 125 150
3 5 7 10 15 20 25
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0,3 0,5 0,6 1 1,3 1,6 1,9
Total pipe length: Loverall = Lstraight + Lequivalent
or roughly: Loverall = 1,6 x Lstraight
2. Understanding Compressed Air2. Understanding Compressed Air
Pressure dropIf the normal working pressure of a pneumatic tool is 6 bar (g),If the normal working pressure of a pneumatic tool is 6 bar (g), any increase above that pressure costs money.
Example:V = 30 m3/min demand at 7 bar (g) 160 kWAt 8 bar (g) approximately 6% more power is required, i.e. around 9.4 kW more
Costs:9.4 kW x 0.05 $/kWh x 4000 h/year = 1880 $/year (13,160 ZAR) !
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Air main:On a well designed air piping system a pressure drop of 0.1 bar is normally expected.
The maximum pressure drop in the air piping systemshould be no more than 1.5 % of the working pressure
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2. Understanding Compressed Air2. Understanding Compressed Air
1. Main piping 0.03 bar2. Loop main (distribution) 0.03 bar
Pressure dropp ( )
3. Connecting lines 0.04 bar4. Refrigeration dryer 0.2 bar5. FRL unit and hose 0.5 bar
max. 0.8 bar
Overall pressure drop 0.8 bar1
2
3 5
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Max. pressure at compressor 7.0 bar (g)Pressure at consumer 6.0 bar (g)Difference 1.0 bar 4
2. Understanding Compressed Air2. Understanding Compressed Air
GThe right fittings
C E
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AB
F
A. Valve (we recommend ball valves)B. Filter (separation of water and rust)C. Regulator (constant working pressure)D. Lubricator (mostly oil mist lubricators)E. Quick release couplings (flexibility at the workplace)F. Hose (length: 3-5 m)G. Tool balancer (reduction of work effort)
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2. Understanding Compressed Air2. Understanding Compressed Air
Points to be observed when sizing and gchoosing air system piping:
Cross-section of the pipe• Air consumption• Length of the piping
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g p p g• Working pressure• Pressure drop• Flow resistance
2. Understanding Compressed Air2. Understanding Compressed Air
Points to be observed when sizing and o ts to be obse ed e s g a dchoosing air system piping:
Pipe layout• Loop/spur main• Connecting lines
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Connecting lines• Dead-end lines• Pipe connections• Fittings
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2. Understanding Compressed Air2. Understanding Compressed Air
Points to be observed when sizing and
Fittings andconnections• Types of outlets• Shut-off valves
• Lubricators• Particulate filters• Oil filters
choosing air system piping:
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• Stopcocks• Condensate separators
O e s• Regulators• Hoses • Couplings
2. Understanding Compressed Air2. Understanding Compressed Air
Points to be observed when sizing and choosing airPoints to be observed when sizing and choosing air system piping:
Choice of materials• Environmental conditions (humidity, temperature, chemical pollution of the air)• Quality of the air (moisture content oil content
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• Quality of the air (moisture content, oil content,temperature)
• Costs• Expected working life
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2. Understanding Compressed Air2. Understanding Compressed Air
Uncontrolled Storage:With t P Diff ti l
Air OutWithout Pressure Differential
Quiet zone
Moisture separator
Protects downstream equipment from oil slugs
Air In
9.5 bar
9.5 bar
37
equipment from oil slugs
Prevents compressor from excessive cycling No “ Real” StorageNo “ Real” Storage
2. Understanding Compressed Air2. Understanding Compressed Air
4,000 140
Uncontrolled pressure and flow
500
1,000
1,500
2,000
2,500
3,000
3,500
Pressure (psig)
Flow
(scf
m)
120
100
80
60
40
20
38
0
04:2
6:25
.00
05:0
1:25
.00
05
:36:
25.0
0
06:1
1:25
.00
06
:46:
25.0
0
07:2
1:25
.00
07
:56:
25.0
0
08:3
1:25
.00
09
:06:
25.0
0
09:4
1:25
.00
10:1
9:31
.00
10
:54:
31.0
0
11:2
9:31
.00
12
:04:
31.0
0
12:3
9:31
.00
13
:14:
31.0
0
13:4
9:31
.00
14
:24:
31.0
0
14:5
9:31
.00
15
:34:
31.0
0
16:0
9:31
.00
16
:44:
31.0
0
17:1
9:31
.00
17
:54:
31.0
0
18:2
9:31
.00
19:0
4:31
.00
19
:39:
31.0
0
20:1
4:31
.00
20
:49:
31.0
0
21:2
4:31
.00
21
:59:
31.0
0
22:3
4:31
.00
23
:09:
31.0
0
23:4
4:31
.00
Time
0
PressureFlowAverage Flow
-
20
2. Understanding Compressed Air2. Understanding Compressed Air
Controlled Storage:With Pressure Differential
Air Out
7 5 b
Flow Controller
With Pressure Differential
Quiet zone
Moisture separator
Protects downstream equipment from oil slugs
Prevents compressor from excessive cycling
Air In
9.5 bar
7.5 bar
3 m3
6 m3 Useable Storage!
39
y g
PLUS 6 m3 of useable air in storage!
Pressure DifferentialCreates Stored Energy!
2. Understanding Compressed Air2. Understanding Compressed Air Flow
Pressure (Before controller)
Average Flow (Before controller)
Pressure (w/ controller)
Average Flow (w/ controller)Controlled pressure and flow
1,500
2,000
2,500
3,000
3,500
4,000
Pressure (psig)F
low
(scf
m)
120
100
80
60
40
140
40
0
500
1,000
04:2
6:25
.00
05:0
1:25
.00
05:3
6:25
.00
06:1
1:25
.00
06
:46:
25.0
0
07:2
1:25
.00
07:5
6:25
.00
08:3
1:25
.00
09
:06:
25.0
0
09:4
1:25
.00
10:1
9:31
.00
10:5
4:31
.00
11
:29:
31.0
0
12:0
4:31
.00
12:3
9:31
.00
13:1
4:31
.00
13
:49:
31.0
0
14:2
4:31
.00
14:5
9:31
.00
15
:34:
31.0
0
16:0
9:31
.00
16:4
4:31
.00
17:1
9:31
.00
17
:54:
31.0
0
18:2
9:31
.00
19:0
4:31
.00
19:3
9:31
.00
20
:14:
31.0
0
20:4
9:31
.00
21:2
4:31
.00
21:5
9:31
.00
22
:34:
31.0
0
23:0
9:31
.00
23:4
4:31
.00
Time
)
0
20
-
21
2. Understanding Compressed Air2. Understanding Compressed Air
41
-
1
3. 3. Understanding Compressors & Their Application
1
3. Understanding Compressors & Their Application
Types of Compressors
2
-
2
3. Understanding Compressors & Their Application
Compressor types
ejector centrifugal-turbo
axial-turbo
rotary reciprocating
displacementcompressor
dynamic compressor
3
vane liquidring
screw rotaryblower
labyrinth diaphragm
y p g
piston crosshead free-piston
single-rotor double-rotor
helical
3. Understanding Compressors & Their Application
Reciprocating compressorsi l / t tsingle / two stage
Note thedifference:
- single / two stage- single acting / double acting
Installation: - portable
4
- stationary
Application: (single stage)
- common 10 bar- boosters 35 bar
-
3
3. Understanding Compressors & Their Application
Double-actingwith crosshead
Application:High pressure, up to 1000 barin combination with screw compressors.Compression of gas
5
3. Understanding Compressors & Their Application
Reciprocating compressorClearances that affect efficiency
upper piston clearance(dead space)
Clearances that affect efficiency
6
machining tolerances clearances in
valves andvalve recesses
constructionalpeculiarities
-
4
3. Understanding Compressors & Their Application
Effective air delivery with reciprocating compressors
Inlet pressure drop leakage losses heating ofinlet air detrimental
clearancesdisplacement volume
losses
7
Effective air delivery
3. Understanding Compressors & Their Application
1 bar absolute8 bar
top deadcentre
stroke
Upper piston clearance(dead space)
8
bottom dead centre
-
5
3. Understanding Compressors & Their Application
1 bar absolute8 barupper clearance
back expansion
stroke
top deadcentre
bottom dead centre
9
dead centreV is lost from
the displacement
3. Understanding Compressors & Their Application
Compression
air escapes pastthe piston rings
Compression
10
losses
the piston ringsinto the crankcase
-
6
3. Understanding Compressors & Their Application
inlet filter
losses caused by throttlingand filter contamination
Suction
11
3. Understanding Compressors & Their Application
Reciprocating compressors
Volumetric efficiency of singleand two stage compressors 2-stage
1-stage
ffici
ency
12
Volumetric efficiency =theoretical displacement
free air delivery
pressure
Volu
met
ric e
f
-
7
3. Understanding Compressors & Their Application
Rotary Screw compressors
13
• Single Stage Rotary • Two Stage Rotary
3. Understanding Compressors & Their Application
• Single Stage Rotary Screw
• Two Stage Rotary Screw
14
-
8
3. Understanding Compressors & Their Application
Rotary Screw compressorscompressedair
fluid-air mixture
cooled fluid
Construction:
2nd stage, Separator elementa) coarse filter
layer
Fluid separation:
15
fluid with heat of compression
thermostaticvalve
fluid filter
hot fluid
1st stage,centrifugal
b) fine filter layer
3. Understanding Compressors & Their Application
Efficiency - comparison of specific power consumption
Pspec =P* * depending on reference point:- compressor shaft power
Specific power consumption* = power* in kW
Effective FAD in m3 / min
16
Pspec V
p p- motor output power- electric power input
-
9
3. Understanding Compressors & Their Application
Function of the fluid in a lubricated rotary screw
First task:
Second task:Third task:
Fourth task
heat transfer, discharge temperatureapproximately 75 - 80 oC
lubrication of bearings
sealing the gap between rotors andcasing, prevention of metallic contactabsorbing dust,sulphur etc
17
sulphur, etc.
3. Understanding Compressors & Their Application
compressed air inletFluid and aftercooler:
compressed air inlet80 °C
cooling air inlet20 °C
cooling air outlet
18
compressed air outlet26 °C
g40 °C
Delta-t = 6 K
-
10
3. Understanding Compressors & Their Application
98-99%
2nd stage, fluidFluid separationseparator element
a) coarse filter layerb) fine filter layer
19
1st stage,centrifugal
3. Understanding Compressors & Their Application
Rotary tooth compressors
quieter running thanreciprocating compressors Inlet channel
Advantages:
Disadvantages:
compressors
20
high power consumptionmore expensive8 bar max. gauge pressure
Air discharge
-
11
3. Understanding Compressors & Their Application
Rotary tooth compressor
21
3. Understanding Compressors & Their Application
Rotary sliding vane compressors• single shaft rotary compressor• single shaft rotary compressor
• poor efficiency at high pressures
• high remaining oil content with clean oil injection and oil mist separator
• high maintenance costs to maintain constant efficiency
22
Main applications:2 - 5 barVacuum down to 1 x 10-3 bar
-
12
3. Understanding Compressors & Their Application
Rotary Blowers
Characteristics:capacity: up to 1200 m3/minair flow: 2 or 3 pulsations per working cyclepressure range: - 0.5 to +1 bar (g)speed: 300 to 11000 min-1
Rotary Blowers
23
p
3. Understanding Compressors & Their Application
Scroll compressors
air delivery: up to 0.5 m3/minair flow: constant, no pulsationpressure range: up to 10 bar (g)speed range: up to 3100 min-1
24
1 Gas chamber 4 Oscillating spiral 6 Suction 6 Suction2 Inlet 5 Fixed spiral 7 Discharge3 Discharge 8 Compression
-
13
3. Understanding Compressors & Their Application
Scroll compressorSuction chamberInlet
21
Rotating spiral
Discharge
Pressure chamber
Fixed spiral
25
3. Understanding Compressors & Their Application
ROTARY SCREW COMPRESSOR CONTROLS
26
-
14
Load / Unload Control
27
Load / Unload ControlAverage kW vs Average Capacity w ith Load/Unload Capacity Control
120
40
60
80
100
Per c
ent k
W In
put
28
0
20
0 20 40 60 80 100 120
Per cent Capacity
1 gal/cfm 3 gal/cfm 5 gal/cfm 10 gal/cfm
-
15
Inlet Valve Modulation Control
Rotary Compressor Performance with Inlet Valve Modulation
40.0
60.0
80.0
100.0
120.0
nt k
W In
put P
ower
Rotary Compressor Performance with Inlet Valve Modulation
29
0.0
20.0
0 20 40 60 80 100 120
Per c
en
Per cent Capacity
Inlet modulation - No Blowdown
Variable Displacement Control120.0
Rotary Compressor Performance with Variable Displacement
40.0
60.0
80.0
100.0
Per e
cnt k
W In
put P
ower
30
0.0
20.0
40.0
0 20 40 60 80 100 120Per cent Capacity
Rotary Compressor Performance with Variable Displacement
-
16
Variable Speed ControlVariable Speed Lubricant Injected Rotary Screw Compressor Package
120.0
40.0
60.0
80.0
100.0
Per c
ent k
W In
put P
ower
31
0.0
20.0
0 20 40 60 80 100 120
Per cent Capacity
%kW input vs % capacity With unloading With stopping
©1998 Compressed Air Challenge
Variable Speed Control“Control Gap”
eman
d (m
3 )
Max VFD Output
Base + Max VFD Output
Base +Min VFD Output
Fixed Speed Compressor10.0
12.5
20.0
CONTROLGAP
32
32
12:00a 8:00 a 5:00 p 12:00a
De
Min VFD OutputFixed Speed Compressor
Base Load 10 m3/min2.5
-
17
Variable Speed ControlEliminating “Control Gap”
2 x Base +Min VFD Output16.5CONTROLOVERLAP
man
d (m
3 )
Max VFD Output10.0
Base + Max VFD Output17.0
Base +Min VFD Output9 5CONTROLOVERLAP
2 x Base + Max VFD Output24.0
33
33
12:00a 8:00 a 5:00 p 12:00a
Dem
Min VFD OutputFixed Speed #1 Compressor
Base Load 7 m3/min2.5
9.5 OVERLAP
3. Understanding Compressors
DYNAMIC AIR COMPRESSORS
34
-
18
3. Understanding Compressors & Their Application
Turbo compressors
Centrifugal turbo compressorCentrifugal turbo compressor
35
Characteristics:Capacity: 35 - 1200 m3/minStages: 1 - 6Pressure range: 3 - 40 bar (g)Speed range: 3000 - 80000 min-1
3. Understanding Compressors & Their Application
Characteristics:Capacity: 600 - 30000 m3/minStages: 10 - 25Pressure range: 0 - 6 bar (g)Speed range: 6000 - 20000 min-1
Axial compressor
36
-
19
3. Understanding Compressors & Their Application
Centrifugal turbo compressor
centrifugal impeller
37
Air Flow
Drive axis
Air Flow
3. Understanding Compressors & Their Application
Axial compressor
Axial impeller
38
Drive axisAir Flow Air Flow
-
20
Centrifugal Compressors
• Most Common Dynamic CompressorMost Common Dynamic Compressor– Relatively easy to install
– Attractive first cost esp. larger capacities
– 500 Hp (2000 cfm) -> 15,000.. 20,000 cfmp ( ) , ,
– Efficient operation• Low Specific Power while operating in turndown range• Very inefficient when operating in blow-off
Centrifugal Compressors• Smaller size centrifugals now availableg
– Over lap in performance with large positive displacement compressors
– More combined systems with a mix of positive displacement and centrifugal machines.
• Dynamic Control -> Constant Pressure
• Displacement Control -> Pressure Band
• Special Considerations when Controlling Mixed Systems
-
21
Centrifugal Compressors• Centrifugal Compressor Driversg p
– Range 200 Hp through 3,500+ Hp
– Electric motors are common• 208, 230/460, & 575 volt / 3 phase / 60 Hz• 220, 380-400 volt / 3 phase / 50 Hz• Synchronous 1.0 or 0.85 leading optional > 500 Hp• Large compressor motors medium voltage
– 2,300 or 4,160 volt / 60 Hz; 3600 volt / 50 HzMedium Voltage (1kV 35 kV) * Medium Voltage ANSI/IEEE 1585 2002– Medium Voltage (1kV - 35 kV) Medium Voltage - ANSI/IEEE 1585-2002 [It is assumed that this is ac.]
– Other air compressor drivers• Engine drive, natural gas and diesel• Steam Turbine drive• Gas turbine drive in larger sizes
3. Understanding Compressors & Their Application
Construction of a Centrifugal compression stage
Impeller blades
Air Flow
g p g
42
Impeller
casing
-
22
3. Understanding Compressors & Their Application
Centrifugal impeller velocities
At inletC1 = velocity of the air to be compressedU1 = peripheral speed of the compressor
impeller W1= relative velocity between air and
compressor impeller
At outletC2 = velocity of the air to be compressed
43
U2 = peripheral speed of the compressor impeller
W2 = relative velocity between air and compressor impeller
3. Understanding Compressors & Their Application
centrifugal impeller, singlesided
di ti fImpeller profile direction of rotation
Impeller profilebackward-bent impeller vanes
44
air flow
-
23
3. Understanding Compressors & Their Application
Turbo compressor: Throttle controlTurbo compressor: Throttle control
45
Partial load
3. Understanding Compressors & Their Application
Turbo compressor: Throttle controlu bo co p esso ott e co t o
46
Full load
-
24
3. Understanding Compressors & Their Application
Turbo compressor: Volume controlInlet guide vanes - Full load
47
3. Understanding Compressors & Their Application
T b V l t lTurbo compressor: Volume controlInlet Guide Vanes – Closed
48
Partial load
-
25
Centrifugal Compressor Performance• Dynamic Compression
– Air enters the eye of the impeller
– Velocity increases to the impeller tip
– Air enters the diffuser and volute
– Velocity decreases energy converts to pressure
– Air exits to the inter-stage
– The process repeats
Centrifugal Compressor Performance
rge
e • Dynamic Compression
Headpsig
Surg
Line
DesignPoint
Chokeor
StonewallRegion
• Dynamic Compression– Flow –vs – Pressure –
Power Curve
Flow (cfm)
PowerbHp
-
26
Centrifugal Compressor Performance
rge
e of m • Dynamic Compression
Headpsig
Surg
Line
DesignPoint
Chokeor
StonewallRegion
Locu
s o
Max
imum
Effic
ienc
y
Dynamic Compression– Flow –vs– Pressure – & Power Curve – with Locus of Maximum
Efficiency
Flow (cfm)
PowerbHp
Centrifugal CompressorPerformance
Surg
eLi
ne
• Dynamic Compression
Headpsig
DesignPoint
Chokeor
StonewallRegion
Throttling
Blow-offExcess Flow
100 %
100 %
Dynamic Compression– Throttling Range – Blow-off
Flow (cfm)
PowerbHp
MinimumSafe Flow
80% (Typical)
Constant PowerDuring Blow-off
100 %
100 %
80 %
-
27
Centrifugal CompressorPerformance
Centrifugal Compressor Performance
Headpsig
Surg
eLi
ne
DesignPoint
Chokeor
Stonewall
Throttling
Blow-offExcess Flow
110 psig
100 psig
90 psig
120 psig Positive
DisplacementCompressor
Artificial Demand
Flow (cfm)
StonewallRegion
PowerbHp
MinimumSafe Flow
80% (Typical)
Constant PowerDuring Blow-off
100 %
100 %
80 %
80 psigSystem Target
Pressure
-
28
Centrifugal Compressor Performance
Centrifugal Compressor Performance
-
29
Centrifugal Compressor Performance
Head
Surg
eLi
ne
Headpsig
DesignPoint
Chokeor
StonewallRegion
Throttling
Blow-offExcess Flow
100 %
110 psig
100 psig
90 psig
80 psig
120 psig Positive
DisplacementCompressor
System Target
Pressure
Storage Delta-P
Flow (cfm)
PowerbHp
MinimumSafe Flow
80% (Typical)
Constant PowerDuring Blow-off
100 %
100 %
80 %
Centrifugal Compressor Performance
• Major HVAC Equipment Manufacturer• Major HVAC Equipment Manufacturer– Multi-building site 3.5 million sq. ft.
– Power House multiple mixed compressors
– 3 additional centrifugals in 3 locations
– Operating with multiple machines in blow-off
-
30
Centrifugal Compressor Performance
• Project Goals• Project Goals
– Cost effective reduction in energy use
– Improve system reliability
– Consistent pressure to support production
– Eliminate compressed air related downtime
Centrifugal Compressor Performance• Project Implementationj p
– $ 23,000 Assessment– $ 68,000 (1) Flow & (3) backpressure controls– $ 8,000 reuse (2) 30,000 gal LP Tanks– $ 47,400 (14) Thermal mass flow transducers– $ 39,900 (4) microprocessors, BMS– $ 10,300 (10) Digital power kW / kWh meters
$ 96 800 E i i I t ll ti T i i– $ 96,800 Engineering, Installation, Training
– $ 293,600 Total Project Cost– 36% Reduction in Energy Use– 3.7 Mwh Annual Energy Savings
-
31
Centrifugal Compressor Performance
• Project Life Cycle Cost• Project Life Cycle Cost– $ 293,600 Total Project Cost– $ 280,000 Annual Energy Savings– Simple Payback 1.05 years
– 3.7 Megawatts Annual Energy Savings– 15 year project life $4.2 million total savings
Centrifugal Compressor Performance
• Centrifugal Compressor MaintenanceCentrifugal Compressor Maintenance– Routine operational checks and maintenance items are
critical.
– Minor maintenance items that are not repaired can result in major failures.
– Check capacity and surge controls, along with safety shutdowns
– Other checks per the manufacturer’s recommendations
-
32
Centrifugal Compressor Performance
• Centrifugal Compressor MaintenanceCentrifugal Compressor Maintenance– Centrifugal compressors are less forgiving than other
designs.
– Routing checks and maintenance are important epically in harsh environments.
If there is a history of marginally effective routine– If there is a history of marginally effective routine maintenance, consider alternatives.
– Run to failure maintenance of centrifugal compressors is very expensive.
3. Understanding Compressors & Their Application
• Key Points– There are two broad categories of industrial air compressors, positive
displacement and dynamic.
– Reciprocating compressors are positive displacement compressors.
– Rotary screw compressors are also positive displacement compressors.
– Rotary screw compressors are the most common type of industrial air compressor.
64
compressor.
– There are many different types of part load capacity control for rotary screw compressors.
– Different types of part load capacity control have different part load power characteristics.
-
33
3. Understanding Compressors & Their Application
• Key Pointsy
– Centrifugal air compressors are the most common type of dynamic compressor used by industry.
– Aerodynamic design determines the head -vs- flow performance curve for centrifugal air compressors.
65
– Operating centrifugal compressors with blow-off control can be extremely inefficient.
– Operating in the stonewall (or choke) region of a centrifugal compressor's performance range is in efficient.
3. Understanding Compressors & Their Application
• Key Pointsy
– When operating multiple centrifugal air compressors in a system it is preferable to throttle multiple compressor as opposed to operating in blow-off.
– When operating a system using a combination of positive displacement and centrifugal compressors requires special
tt ti t t l t t d th t '
66
attention to control strategy and the system's pressure profile.
– Performing poor routine maintenance for centrifugal air compressors can lead to expensive failures of major air compressor components.
-
1
4. 4. Understanding Air gTreatment
1
4. Understanding Air Treatment
Impurities in the air
2
Regardless of which type of construction, all compressorsdraw in the impurities in the air and concentrate them many times
-
2
4. Understanding Air Treatment
Solid particles in the air%
3
Size in micron5-10µm 10-20µm 20-40µm 40-80µm0-5µm
4. Understanding Air Treatment
Overall hydro carbon concentrationMean daily value (mg/m3)
10
12
14
16mg/m3
Mean daily value (mg/m )Location: a small German town
Period: July 1992
4
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 310
2
4
6
8
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
-
3
4. Understanding Air Treatment
Sulphur-dioxide (SO2) concentrationPeriod: July 1991 - June 1992
0·08
0·10
0·12
0·14
ppm
Period: July 1991 June 1992Location: a small German town
5
0
0·02
0·04
0·06
0 08
Jul-91 Aug-91 Sep-91 Oct-91 Nov-91 Dec-91 Jan-92 Feb-92 Mar-92 Apr-92 May-92 Jun-92Jul-91 Aug-91 Sep-91 Oct-91 Nov-91 Dec-91 Jan-92 Feb-92 Mar-92 Apr-92 May-92 Jun-92
4. Understanding Air Treatment
mg/m3
Concentration in mg of mineral oil / m3 airTime period 8:00 - 17:00
Gear grinding workshop
Drilling workshop
Turning shop
Other
mg/m Time period 8:00 17:00
6
-
4
4. Understanding Air TreatmentQuality classification of compressed airto ISO 8573-1: 2001 (E)
ISO
8573-1
Class
Solid particle content Moisture contentOil
contentmax. number of particles per m³ sized d [μm]
µm mg/m³
PDP / (x=liquid water content g/m³ ) mg/m³ 0,1 0,1< d 0,5 0,5< d 1,0 1,0< d 5,0
0 as specified by the equipment user or supplier and more stringent than class 11 - 100 1 0 - - -70 °C 0,012 - 100.000 1.000 10 - - -40 °C 0,13 - - 10.000 500 - - -20 °C 1,0
7
4 - - - 1.000 - - +3 °C 5,05 - - - 20.000 - - +7 °C -6 - - - - 5 5 +10 °C -7 - - - - 40 10 x 0,5 -8 - - - - - - 0,5 x 5,0 -9 - - - - - - 5,0 x 10,0 -
4. Understanding Air Treatment
Air quality downstream of the compressor
8
-
5
4. Understanding Air Treatment
CONDENSATE:
9
This compressor with an air delivery of 5 m3/min (referred to +20° C, 70 % moisture carry-over
and 1 bar absolute) transports around 30 litres ofwater into the air main during an 8 hour day
4. Understanding Air Treatment
CONDENSATE:around 20 litres of this water
accumulates in the aftercoolerin the form of condensate (at
7 bar gauge working pressureand an outlet temperature of
+30° C at the aftercooler)
10
-
6
4. Understanding Air Treatment
CONDENSATE:As the air cools down further the remaining 10 litres
accumulate at convenient points in the air main
the results are expensivemaintenance, repairs and d f t i
11
defects in production
4. Understanding Air Treatment
Water Content of Ambient AirDewpoint g/m3
+100+90+80+70+60
588.208417.935290.017196.213129.020
Dewpoint g/m3
+6+4
+0-10
7.2466.3595.5704.8682.156
+2
12
+50+40+30+20+10+8
82.25750.67230.07817.148
8.3429.356
-20-30-40-50-60-70
0.880.330.1170.038
0.00330.011
-
7
4. Understanding Air Treatment
P d i
pressuredewpoint in degrees °C.
Pressure dewpoint -atmospheric dewpoint
Example:Pressure dewpoint: 2-3 °C.Working pressure: 7 bar
13
Working pressure: 7 barAtmospheric dewpoint: - 25 °C.
atmospheric dewpoint in °C.
4. Understanding Air TreatmentCompressed air drying methodsDiffusion
Solid drying
Adsorption (desicc.)
Liquid drying method
Absorption
SorptionCondensation
Mechanism Cooling
RefrigerationCoolingOverpressurisation
14
Regeneration
Warm airregeneration
HeatedHeatless
Solid drying Deliquescentdrying
-
8
4. Understanding Air Treatment
Why Dry Compressed Air?Untreated air
dirt
oil aerosols
moisture
Problems in the air main
corrosion
pressure loss
contamination
Problems with equipment
contamination
tool wear
scrap
Why Dry Compressed Air?
15
freezing
maintenance
p
downtime
COSTSCOSTS
4. Understanding Air Treatmentair outlet
air inletCondensate separation
cyclonicair movement
deflectorTo ensure sufficient separation,liquids and heavy particles are
subjected to centrifugal forces athigh rates of flow.
The degree of separation is around 95% t 6 b 20 °C d th i l
16
condensate collection
air movement95% at 6 bar, 20 °C and the nominalvolumetric flow rate. The pressure
drop is approximately 0.05 bar .
-
9
4. Understanding Air Treatment
Condensate separation
The compressed air discharged from the aftercooler of a compressor is normally 100% saturated with water vapor. If the temperature of the compressed air falls, the water vapor condenses.
A coarse separation of the condensate
17
compressedair outlet
condensatecollector
condensatedrain
A coarse separation of the condensate can be achieved if the pipework and the compressed air outlets are installed as shown in the illustration.
4. Understanding Air Treatment
Condensate separation
• used directly at the takeoff point• mechanical filter • rotating movement• deflection plate• condensate drain (important!)
Fine filter
18
condensate drain (important!)
-
10
4. Understanding Air Treatment
Simplest methodDisadvantage: high energy requirement
Over-compressing
Suction of atmospheric air,
high compression e.g. 300 bar (g),
Example:
High-voltage safety switchWorking pressure 15 bar (g)Preliminary compression to 300 bar (g)
Manufacture of high pressure cableWorking pressure 0.5 bar (g)Preliminary compression to 30 bar (g)
19
cooling the airand separationof condensate,
decompression to15 bar (g).
high humiditylow humidity
4. Understanding Air Treatment
Refrigeration drying
1. Air inlet2. Air to air heat exchanger3. Refrigerant to air heat exchanger4. Refrigerant compressor5. Condensate separation,
automatic condensate drain
20
6. Compressed air outlet
-
11
4. Understanding Air TreatmentHigh Inlet Temperature Refrigerated Dryer
Description:
Air inlet temperatures up to 82 °C Centriflex separator system Automatic, float-controlled
condensate drain
Ideal for reciprocating compressors
Description:
Advantages:
21
Pressure dew point +10 °C : selected to suit the practical requirements of reciprocating compressor operation
Hot gas-bypass valve for constant PDP
4. Understanding Air Treatment
The hot-gas bypass controller allows high-pressure refrigerant gas to flow g yp g p g gto the inlet of the refigerant compressor under fluctuating load.
This ensures constant temperature cooling of the compressed air.
> no pressure dew point fluctuations> no danger of freezing
22
-
12
4. Understanding Air TreatmentAir inlet
Separator systems
First stage of separation:A special stainless steel insert separates all particles larger than 10 micron, using the basic principle of centrifugal force and deflection. The re-usable separator is fabricated as a
for refrigeration dryersCentriflex
Displaced holes
23
The re usable separator is fabricated as a cartridge and is easy to remove for cleaning.
Air outlet
4. Understanding Air Treatment
Separator systems for compressed air dryersType: Zentri-Dry
mesh of stainless steel
air inlet
air outletwaterseparatorsystem
Type: Zentri Dry
24
condensate
air inlet
stainless steel housing
-
13
4. Understanding Air Treatment
Water Vapor Outlet Water Vapor at Atmospheric Pressure
Air Inlet Air Outlet
Water Vapor Outlet
25
Membrane Dryer
4. Understanding Air Treatment
filler neck for toppingup the drying medium
Absorption dryingmedium
dry airdrying
medium
Chemical processSolid soluble drying mediumDeliquescent drying medium
Periodic renewal of the drying mediumDewpoint: + 15 ° Celsius
Low compressed air inlet temperatures
26
predrying
condensate
humid air
-
14
4. Understanding Air Treatment
Application:Desiccant drying - heatless
Application:Systems subjected to freezing.High ambient temperatures.Extreme requirements of air quality.
1 microfilter (0.01 µm, 0.01 ppm)2 changeover valve
27
g3 flow diffuser4 desiccant bed: moisture adsorption5 outlet collector6 particulate filter 1 µm7 purge (regeneration ) air valve8 desiccant bed: regeneration9 purge air exhaust silencer
Design of the heatless regenerating desiccant dryers 100 % desiccant volume100 % air flow35 °C inlet temperature
Standard Cycle
10
time (min)
4 min regenerating
0.5 min pressurising0.5 min standby
35 C inlet temperature7 bar (g)pressure dew point - 40 °C
Regenerating air requirement:average 14 %
+ chamber filling 1 %
total average 15 %
28
0
5
5 min drying
g g
Regenerating air (max.)
15 % x 5 min
4.5 min 17 %
-
15
Conventional dryers80 % desiccant volume
100 % air flow35 °C inlet temperature
Standard Cycle
10
time (min)
4 min regenerating
0.5 min pressurising0.5 min standby
p7 bar (g)pressure dew point - 40 °C
Regenerating air requirement:average 17 %
+ chamber filling 1 %
total average 18 %
29
Regenerating air (max.)
18 % x 5 min
4.5 min0
5
5 min drying
4 min regenerating
20 %
Economy Dryer
60 % desiccant volume100 % air flow35 °C inlet temperature
Economy Cycle
10
time (min)
35 C inlet temperature7 bar (g)pressure dew point - 40 °C
Regenerating air requirement:average 22 %
+ chamber filling 2 %
total average 24 %
30
0
5
2.5 min drying
2 min regenerating0.25 min pressurising0.25 min standby Regenerating air (max.)
24% x 2.5 min
2.25 min 27 %
-
16
4. Understanding Air Treatment
Desiccant drying -i t ll h t d
- integrated heating rods(desiccant not heated evenly duringregeneration)
- low purge air requirement (cooling,pressure build-up)
internally heated
31
- constant dry, oil-free and cleancompressed air
4. Understanding Air TreatmentDesiccant drying - externally heated
1 microfilter (0.01 µm, 0.01ppm)2 changeover valve3 flow diffuser4 desiccant bed: adsorption 5 outlet collector6 regeneration (purge) valve7 particulate filter
32
8 desiccant bed: regeneration 9 purge air inlet
10 purge air blower11 purge air heating12 purge air outlet
-
17
4. Understanding Air Treatment
1 microfilter (0 01 µm 0 01ppm)
Desiccant drying, externally heat regeneratedPrinciple of no compressed air loss: 1 microfilter (0.01 µm, 0.01ppm)
2 changeover valve3 flow diffuser4 desiccant bed: adsorption5 outlet collector6 particulate filter7 purge air blower
Principle of no compressed air loss:
11
33
8 desiccant bed: regeneration 9 purge air heating
10 changeover valve11 purge air inlet12 purge air outlet
12
7 microfilter 0.01µm8 changeover valve9 flow diffuser
10 desiccant bed11 outlet collector12 particulate filter13 blower14 purging (regeneration) of drying
1 compressed air inlet2 air/air heat exchanger3 refrigerant/air heat
exchanger4 refrigerant compressor5 automatic condensate drain 14 purging (regeneration) of drying
medium15 purge air heating16 changeover valve17 purge air recovery18 cooling/purge air outlet
5 automatic condensate drain6 compressed air outlet
12
15
171311
34
5 18
14
16
-
18
4. Understanding Air Treatment
100 %Absolute
Refrigerationdryers
Adsorptiondryers
Absolutehumidity Ranges of
dryer application
35
020400 %
-40-20
After-cooler
Pressure dewpointt
4. Understanding Air Treatment
Pressure dewpoints for some areas of application
Area of application Required pressure dewpoint in °C
Workshop air - indoor pipework
Paint spraying
Instrument air
Air motors
10 to - 10
10 to - 25
10 to - 40
10 to - 40
36
Sand blasters
Pneumatic tools
Packaging
Plastics industry
5 to 0
5 to - 25
5 to - 25
5 to - 40
-
19
4. Understanding Air TreatmentHow large are the impurities in the air?
Description: vapour / mist / smoke dust fog: spray rain
Perception: Description: microscopic visualPerception: Description: microscopic visual
Falling time at 1 m heightSec.
Min.
foundry sandheavy industrial smogwater mist
carbon dusttraffic dust
cement dustpollen
plant sporesbacteria
metallurgical dust
oil mistoil vapoursVirusestobacco smoke
paint spray mist
Influence of the Brownian Molecular movement
37
tobacco smokegas molecules
pore dia, activ. carbon, silica-gel, etc.
centrifugalnormal
heavybag-typeair filter
separation and filtration performance
Particle size in microns
4. Understanding Air Treatment
Permissible particle sizes
Compressed airusage
Permissible particlesize in micron
rotary vane air motorspercussion tools
cylindercontrollers
40 - 20
20 - 5
p
38
control systems. instru-ments, spray guns
fluidic elements, phar-maceutics. electronics
pure breathingair
5 - 1
< 1
0.01
-
20
4. Understanding Air Treatment
Current hydro carbon carry-over limits
Application Max. hydro carbon carry-overin compressed air in mg/m3
Working airNormal breathing air
< 5
for various applications
39
Testing air
Pure breathing air
Oil-free air
< 1
< 0.5
< 0.003
4. Understanding Air Treatment
Prefilter
Streamed from the inside to the outside.Used as a liquid filter
Principle the same as all deep bed filters
used as a coarse filter for 100% saturated compressed air (or for water vapor components in the liquid phase)
40
Principle the same as all deep-bed filters
-
21
4. Understanding Air Treatment
Particulate filter
Streamed from the outside
used as dust filterfor dried air (e.g.downstream of adesiccant dryer)
41
Streamed from the outside to the inside. Used as surface filter
4. Understanding Air Treatment
MicrofilterMicrofilter
0.01 to 0.001 micronfor liquids(aerosols) and particles
42
Streamed from the inside to the outside. Used as a deep-bed filter
-
22
4. Understanding Air TreatmentHow does the microfilter work?
contaminated air filter medium (deep-bed filter) technically oil-free clean air
43
Direct interception
Impact
Diffusion /Coalescence
4. Understanding Air Treatment
Coalescing filter behaviour in the partial load range
0 010
0.015
0.020
0.025
Rem
aini
ng o
il m
g/m
³
Filter (old)
44
10 20 30 40 50 60 70 80 90 100 110 120 130
0.005
0.010
Loading (flow in %)
Filter (old)Filter (new)
-
23
4. Understanding Air Treatment
Quality of inlet air:Activated carbon adsorberQuality of inlet air:
hydro carbon content 0.01 m
• long contact time of the air and activated carbon bed
• long and reliable life
Particulate
filter 1 µm
(recommended)
45
g
• hydro carbon indicator for continuous quality control
Quality of outlet air:
hydro carbon content 0.003 mg/m3
4. Understanding Air Treatment
Condensate drainage
46
Reliable drainage must be ensured at all condensate collectingpoints of the air main
-
24
4. Understanding Air Treatment
Condensate drains: float type
Drainage occurs only when sufficient condensate has collected
condensate inlet
air back flow line connection
47
No compressed air blowoff
Regular maintenance required
manual valvecondensate
outlet
4. Understanding Air Treatment
Condensate drains: solenoid valve,
1
3
2
1 ball valve2 dirt trap3 solenoid valve with
integrated or externaltimer
,timer controlled
48
• automatic and regular drainage• interval 1.5 to 30 min• opening period 0.4 to 10 sec• condensate can be directed into a disposal canister
-
25
4. Understanding Air Treatment
Condensate drains: Electronic level-sensing typeCapacitive level sensingAutomatic pressure matchingSelf-monitoringVolt-free alarm contact
49
2 collection chamber 9 discharge pipe6 level sensor8 valve seat
1 condensate inlet 4 solenoid valve2 collection chamber 5 valve diaphragm
3 pressure balance line
4. Understanding Air Treatment
What’s the reason for treating condensate?
50
Regardless of which type of construction, all compressorsdraw in the impurities in the air and contentrate them many times
-
26
4. Understanding Air Treatment
Condensate: Oil-Water separator
1 condensate inlet2 expansion chamber3 separating tank: gravitational separation4 oil overflow drain5 oil collector tank6 prefilter: retention of solids 7 adsorption filter: retention of oil particles8 water drain (clean water)
51
Used to separate condensate dispersions
( )
4. Understanding Air Treatment
Pollutants in the condensate of oil-freed il l d it
Sample
oil-free
fluid-injected
oil-free
fluid injected
HC mg/l
4.2
7.1
7
0 1
Ph Cu mg/l
7 1
6.6
5.5
Zn mg/l
0.75
1
0.22
0 04
Cl mg/l
1.3
1
2.4
1
Pb mg/l
0.2
0.2
0.2
0 2
Fe mg/l
0.2
0.2
0.2
0 2
Na mg/l
1.6
0.12
0.45
0 64
2.5
1.7
1.1
0 11
4.7
and oil-cooled compressor units
52
fluid-injected
oil-free
oil-free
0.1
5.3
16
7.1
4.2
6.2
0.04
2
2.2
1
6.4
1
0.2
2.1
0.2
0.2
4
0.2
0.64
1.5
0.76
0.11
0.11
HC .... Hydro carbon contentPh .... ph value
-
27
4. Understanding Air Treatment
53
-
1
5. 5. Understanding Systems
The Demand Side
1
5. Understanding Systems
Pneumatic PowerPneumatic PowerAir Flow > Mass or Weight of AirPressure > Potential Energy
Increasing – or – DecreasingFl P
2
Flow – or – PressureIncrease – or – Decrease
Power Delivered & Power Consumed
-
2
5. Understanding Systems
5 TON CLAMP CYLINDER12” Bore x 10” Stroke5.6 Tons @ 100 psig
5 Ton Clamping Cylinder1.5 seconds4 cycles per minute320mm Bore (45,000 Newtons @ 6.9 bar)250mm Stroke Length
Time Required to Clampand Unclamp is 1.5 Seconds
Machine Operates at4 Cycles / Minute
MainlineCompressed Air
Header
3
Filter Regulator Lubircator
5. Understanding Systems
Cylinder Volume CalculationCylinder Volume Calculation
Cylinder Air Use
meterscubiclrV 02.0
1000250)160(
1000 32
3
2
4
-
3
5. Understanding Systems
Cylinder Average Air Demand (1 i t )Cylinder Average Air Demand (1 minute)
What Size Components?Air Line Size
5
Air Line Size _______________________Filter, Regulator, Lubricator ___________Valve Size _________________________
5. Understanding Systems
Cylinder Peak Dynamic Flow RateCylinder Peak Dynamic Flow Rate
What Size Components Now?Air Line Size
6
Air Line Size _______________________Filter, Regulator, Lubricator ___________Valve Size _________________________
-
4
5. Understanding Systems
•When does the Peak Air Flow Occur?•When does the Peak Air Flow Occur?
•When is the High Pressure Required?
•What Size Components Now?
7
•What Size Components Now?
5. Understanding Systems
•Flow Static Demand•Flow Static DemandPeak air flow and minimum pressure required do not occur simultaneously.
•Flow Dynamic Demand
8
Peak airflow rate and minimum pressure required must occur simultaneously.
-
5
•Perceived High Pressure Demands
5. Understanding Systems
Perceived High Pressure DemandsOften Dictate the System Pressure
Validate Pressure Requirements
Rule Out Excessive Pressure Drop
Measure Flow & Pressure (Data Logging)
Evaluate • Connection Practice – Modify Equipment – Storage – Pressure Boosters
9
5. Understanding Systems
Validate Perceived High PressurePressure Gauges – Mechanical DampingPressure Gauges Mechanical Damping
Air System AuditPoint of Use (P5) Pressure @ Test Machine
5.8
6
6.2
6.4
6.6
6.8
7
Pres
sure
(bar
)
10
5
5.2
5.4
5.6
11:05 11:10 11:15 11:20 11:25 11:30
Time of Day 11/13/92System Supply Pressure (bar) Header Pressure (bar)Average Point of Use Pressure (bar) Minimum Point of Use Pressure (bar)
© 1992 Tom Taranto
-
6
5. Understanding Systems
Test Machine Flow Dynamic DemandWhat’s Wrong With This Picture?What s Wrong With This Picture?
11
•High Volume Intermittent Demand
5. Understanding Systems
•High Volume Intermittent DemandConsume Large Airflow for Short Periods
High Peak Airflow Rate and Low Average Demand
Affects the System Pressure ProfileControl Signals Supply PressureDistribution Gradient Use Point Pressure
12
-
7
High Volume Intermittent Demand
5. Understanding Systems
High Volume Intermittent Demand•Wastes Energy
Initiates Compressor Start-upOperational Remedy – Increased PressureAdds to Artificial Demand
•Data Logging Airflow & Pressuregg gPeak Airflow RateDuration of Event & Total Air ConsumedDwell Time Between Events – Storage RefillEvaluate Control Response & Excess Supply Pressure
13
5. Understanding Systems
High Volume Intermittent DemandHigh Volume Intermittent Demand Event - Dynamic Profile
5.6
5.8
6
6.2
6.4
6.6
6.8
7
7.2
Pres
sure
(bar
)
8
10
12
14
16
18
20
22
24
Flow
to S
yste
m (m
3/m
)
Dense Phase Transport System (Tanks 1 & 2) - Test 2
14
4.8
5
5.2
5.4
11:25 11:26 11:27 11:28 11:29 11:30 11:31 11:32 11:33 11:34 11:35 11:36 11:37
Time of Day on Tuesday 03/20/2001
0
2
4
6
System Pressure (bar) Event Flow @ Tanks 1&2 (m3/m)
Page 2
© 2001 Tom Taranto
-
8
•Pipe Layouts – Point of Use Piping
5. Understanding Systems
Pipe Layouts Point of Use Piping Delivers Air From Header to – Demand Energy = Airflow & Pressure
•1 to 2 bar Loss in Point of Use Piping is Common Poor Unreliable, Inconsistent Applications Performance Don’t Increase Pressure Don t Increase Pressure Decrease Piping Resistance
15
5. Understanding Systems
16
• Which Piping Configuration Performs Best?
-
9
Key Points
5. Understanding Systems
Key Points• Identify dynamic airflow conditions of average
–vs- peak airflow.
• Classify air demands as Flow Static and Flow Dynamic.
• Point of use connection practice has a significant affect on applications performance.
17
– Key Points
5. Understanding Systems
– Key Points• Review perceived high pressure air
demands to validate their pressure requirements.
P h l t• Pressure gauges have slow response to pressure changes. It may be necessary to use pressure transducers and high-speedsampling to capture pressure dynamics.
18
-
10
Key Points
5. Understanding Systems
Key Points• Minimize the use of hose for connections.
Hose has much smaller ID size (higher pressure drop) than pipe.
• Where hose must be used select the hose size based on the inside diameter and peaksize based on the inside diameter and peak airflow rate. Avoid the use of hose barbs and pipe clamps, they are dangerous, very restrictive and frequently develop leaks.
19
Key Points
5. Understanding Systems
Key Points • Do not use redundant point of use dryers, filters, etc.
as each component represents additional pressure drop.
• Avoid over filtration, maintain an appropriate compressed air cleanliness class for the application requirements.
• Size all connection equipment to the actual dynamic conditions associated with the application.
• Account for to peak airflow rate that must be supported, do not size equipment based on average airflow rate.
20
-
11
5. Understanding Systems
BALANCING THE SUPPLY TO DEMAND
21
5. Understanding Systems
• Supply > Demand ~ Pressure
Demand > Supply Pressure• Demand > Supply ~ Pressure
22
-
12
5. Understanding Systems
• Air System Minimum Pressure• Air System Minimum PressureWhat is the correct pressure?What is the Cost?
• Increased Air Pressure = Waste
23
Artificial Demand Increasing Pressure Increases Airflow
• Artificial Demand
5. Understanding Systems
– Increasing pressure applied to a hole in the air system, increases the airflow through the air system.
– Leaks and unregulated air demands all have a potential component of artificial demand.
– Leak repair without pressure control is not fully effective.
24
-
13
5. Understanding Systems
Discharge of Air Through an OrificeIn cubic meters of free air per minute at standard atmospheric pressure 1.013 bar absolute and 21° C
Gauge pressure
before orifice, bar
Diameter of Orifice, mm
1 2 3 4 5 6 7 8 9 10 15 20
4 0.03 0.11 0.25 0.45 0.70 1.01 1.38 1.80 2.28 2.82 6.34 11.284.5 0.03 0.12 0.28 0.50 0.78 1.12 1.52 1.98 2.51 3.10 6.98 12.40
5 0.03 0.14 0.30 0.54 0.85 1.22 1.66 2.16 2.74 3.38 7.61 13.535.5 0.04 0.15 0.33 0.59 0.92 1.32 1.79 2.34 2.97 3.66 8.24 14.65
6 0.04 0.16 0.35 0.63 0.99 1.42 1.93 2.52 3.19 3.94 8.87 15.786.5 0.04 0.17 0.38 0.68 1.06 1.52 2.07 2.70 3.42 4.23 9.51 16.90
7 0 05 0 18 0 41 0 72 1 13 1 62 2 21 2 88 3 65 4 51 10 14 18 03
25
7 0.05 0.18 0.41 0.72 1.13 1.62 2.21 2.88 3.65 4.51 10.14 18.037.5 0.05 0.19 0.43 0.77 1.20 1.72 2.35 3.06 3.88 4.79 10.77 19.15
8 0.05 0.20 0.46 0.81 1.27 1.82 2.48 3.24 4.11 5.07 11.40 20.278.5 0.05 0.21 0.48 0.86 1.34 1.93 2.62 3.42 4.33 5.35 12.04 21.40
9 0.06 0.23 0.51 0.90 1.41 2.03 2.76 3.60 4.56 5.63 12.67 22.529.5 0.06 0.24 0.53 0.95 1.48 2.13 2.90 3.78 4.79 5.91 13.30 23.6510 0.06 0.25 0.56 0.99 1.55 2.23 3.03 3.96 5.02 6.19 13.94 24.77Table is based on 0.61 coefficient of flow.
5. Understanding Systems
Engineer Appropriate StorageAir System Audit - Artificial Demand Reductiony
Test #21 Throttled System Response
6.9
7
7.1
7.2
7.3
7.4
7.5
7.6
7.7
7.8
7.9
8
Pres
sure
(bar
)
34
36
38
40
42
44
46
48
50
52
54
56
yste
m F
low
(m3/
m)
26
6.3
6.4
6.5
6.6
6.7
6.8
13:07 13:08 13:09 13:10 13:11 13:12 13:13 13:14 13:15 13:16 13:17 13:18 13:19 13:20
Time of Day 11/14/92
22
24
26
28
30
32 Sty
System Pressure (bar) C#1 225 kW Discharge Pressure (bar)
C#2 262 kW Discharge Pressure (bar) Stystem Flow (m3/m)
© 1992 Tom Taranto
-
14
5. Understanding Systems
Storage; A Lake – vs – A Reservoir
LAKE
AIR RECEIVER
RESERVOIR
AIR STORAGE
27
8.2 barWorking Pressure
6.2 barWorking Pressure
8.2 barStorage Pressure
IntermediateControl
• Stabilize System Operation
5. Understanding Systems
Stabilize System Operation– Minimize the cost of generating compressed air.– Control air demand and reduce artificial demand.– Create controlled air storage to supply peak
demand
• Evaluating Controlled Storage• Evaluating Controlled Storage– Meet surge demands– Satisfy events as defined in the demand profile– Improve compressor control response
28
-
15
5. Understanding SystemsCompressed Air Storage - for Stable System Operation
603 0 bar
Useable air in storage based on receiver size and pressure differential
20
30
40
50ab
le A
ir St
orag
e (m
3 )3.0 bar
2.5 bar
2.0 bar
1.5 bar
1.0 bar
Receiver = 10 m3
Useable Air Storage@ 3.0 bar 30 m3
@ 2.5 bar 25 m3
@ 2.5 bar 25 m3
@ 1.5 bar 15 m3
@ 1.0 bar 10 m3
@ 0.5 bar 5 m3
@ 0.2 bar 2 m3
29
0
10
20
0 2 4 6 8 10 12 14 16 18 20Receiver Size (m3)
Usea
0.5 bar
0.2 bar
5. Understanding Systems
Tuning Compressor & System ControlsAi S t P f T t C iAir System Performance Test Comparison
Properly Tuned System Performance w/ Intermediate Control
5.65.8
66.26.46.66.8
77.27.47.67.8
Pres
sure
(bar
)
40
45
50
55
60
65
70
75
80
85
90
95
Syst
em F
low
(m3 /m
)kW
x 1
0
30
4.44.64.8
55.25.4
19:00
19:10
19:20
19:30
19:40
19:50
20:00
20:10
20:20
20:30
20:40
20:50
21:00
Time of Day on Thursday 5/26/94
10
15
20
25
30
35
S
Storage Pressure (bar) System Pressure (bar )Flow (m3/m) kW x 10 (source)
© 1994 Tom Taranto
-
16
5. Understanding Systems
Tuning Compressor & System ControlsAir System Performance Test ComparisonAir System Performance Test Comparison
Improperly Tuned System Performance w/ Compressor Source Control
5.4
5.6
5.8
6
6.2
6.4
6.6
6.8
7
7.2
7.4
7.6
7.8Pr
essu
re (b
ar)
35
40
45
50
55
60
65
70
75
80
85
90
95
Syst
em F
low
(m3 /m
)kW
x 1
0
31
4.4
4.6
4.8
5
5.2
19:00
19:10
19:20
19:30
19:40
19:50
20:00
20:10
20:20
20:30
20:40
20:50
21:00
Time of Day on Wednesday 5/25/94
10
15
20
25
30
Storage Pressure (bar) System Pressure (bar )
Flow (m3/m) kW x 10 (source)
© 1994 Tom Taranto
5. Understanding Systems
Key Points• Stabilize system operating pressure.• Increased air pressure increases
compressed air demand at leaks and unregulated air demands.
• Leakage can be reduced by controlling
32
to a lower system pressure.• Artificial demand is a component of any
unregulated leak or air demand.
-
17
5. Understanding Systems
Key PointsTarget pressure should be the lowest optimal• Target pressure should be the lowest optimal pressure to supply productive air demands.
• Air storage should be designed to supply surge demands, satisfy events defined in the demand profile, and improve compressor control response.Th t f i t d d
33
• The amount of energy in storage depends on storage volume and controlled pressure differential.
5. Understanding Systems
-
UNIDO Industrial Systems Optimization Module 4 Compressed Air Systems -Instructor Notes
© 2005 US Department of Energy and Lawrence Berkeley National Laboratory – Tom Taranto and Wayne Perry 1
6. Pressure Profile
Graphical description of d icompressed air pressure as
measured throughout the system.
1
Typical pressure measurement locations
• Compressor maximum working pressure (MWP)• Compressor control range• Treatment equipment pressure drop• Pressure differential reserved for primary storage• Supply header pressure to the system• Distribution header pressure in one or more
demand side locations• Point of use connection pressure• End use pressure
2
-
UNIDO Industrial Systems Optimization Module 4 Compressed Air Systems -Instructor Notes
© 2005 US Department of Energy and Lawrence Berkeley National Laboratory – Tom Taranto and Wayne Perry 2
Compressor 001-5040Atlas Copco GA250-100
300 Hp 480 Volt254 kW FL - 56 kW NL
1,448 acfm 107 psig
TA1TP1
Plant Air Compressors
Compressor 001-5130Gardener Denver EAUSAV
300 Hp 416