Compressed Dry Air System
Deo R. Ybarrita Technical & Training Manager
Program Agenda
Air Requirements Requirements
Understanding Air Compression, Distribution & Control
Performance of compressed air system – Compressor efficiency
Operation and control of air compressor, auxiliaries & Accessories
Operator care of air compressor, piping & control systems
Monitoring & inspection of air system – Failure modes & their effects
Evaluation of risk of failure and fitness – for – service
Control techniques
Compressed air system audit
Feed mill compressed air requirements
Instrumentation
Production pneumatic cylinders & valves
Conveyors
Blowers for Waste Water Treatment Plant
Understanding Air Compressor
Basic Parameters
Pressure
Atmospheric Pressure Gauge Pressure Absolute Pressure
Temperature
Ambient temperature
Room temperature
Discharge temperature
°C or °F
Flow rate
Volume per unit time
Psi or Bar
l/s or cfm
Power
Package power
Shaft input power
HP or KW
Understanding Air Compression
Basic Compression
Characteristics of compression
Displacement
Enclosing a volume of air and then increasing the pressure by reducing the area of the enclosed volume
Reciprocating
Rotary
Dynamic
The flowing gas accelerates to a high velocity by means of the rotating blades, after which the velocity of the gas is transformed to pressure
Understanding Air Compression
Types of Compressor
Displacement
Reciprocating
Rotary
Piston Compressor Screw Compressor
Other types
Dynamic
Distribution Air Receiver
Final filter
End User
Pre-filter
Compressor
Refrigerated Air Dryer
Control
% RH = 14 to 26%
Pg = working pressure T out = Cooling air + 10 °C
T inlet < 40 °C Pg = 0 psi
Oil removal = 1 ppm
Oil removal = .01 ppm
Part removal = 1 µm
Part removal = 0.01 µm
PDP = 3 to 10 °C
Compressor Efficiency
% Efficiency = Output / input X 100
CFM / shaft input power
l/s / shaft input power
The higher the cfm / shaft input power the more efficient is the compressor
The higher the motor efficiency the more efficient is the compressor package Power
cfm
Operational and Control of Air Compressor, Auxiliaries & Accessories
Working Principle
Airflow Oil Flow Regulation
Operating Principle : Air Flow Air Filter Inlet Valve Assembly Compressor Element
Air Intake
Minimum Pressure Valve Air Cooler
Cooling Fan Moisture Trap
Check Valve Delivery Line Float Valve Oil/Air separator tank
Oil Separator Element
Air Flow Control Tin < 40 °C
Toutelement < Tin + 60 °C
Pin = 0 (g)
Pout = WP (g)
Toutcomp = T cool air + 10 °C Pout = WP (g)
Tout < Tin + 60 °C
Pout = WP (g)
Working Principle
- Airflow - Oil
Flow
- Regulation
Operating Principle: Oil Flow
Compressor Element
Oil Cooler Cooling Fan
Check Valve
Oil stop Valve
Thermostatic bypass valve
Scavenging Line
Oil/Air separator tank
Oil Filter
Oil Line
Oil Separator Element
Oil Flow Control - Loading T = Tin + 60 °C P = (WP – 1 to 2 bar) (g)
Tout = (Tin + 60 °C) - 25 P = (WP – 1 to 2 bar) (g)
Tout = (Tin + 60 °C) - 25 P = (WP – 1 to 2 bar) (g)
Air Flow & Oil Flow During Loading Tair = Tcooling air + 10 °C P = WP (g)
Tair = Tin + 60 °C P = WP (g)
100% in inlet, cfm cap Tout = Tin + 60 °C
Toil = (Tin + 60 °C) - 25
P = WP (g)
P = WP (g)
Oil Flow Control - Unloading 10% air inlet, cfm capacity
T = Depends on TBV (60 to 75 °C P = (< 1 bar) (g)
Tout = (Tin + 60 °C) - 25 P = (< 1 bar) (g)
Tout = (Tin + 60 °C) - 25 P = (< 1 bar) (g)
Air flow and Oil Flow During Unloading Tout = (Tin + 60 °C) 25 P = (< 1 bar) (g)
10% air inlet, cfm cap
Regulating System – Load / Unload
Pressure Transducer
Feedbacks signal to elektronikon for data processing
Electrical signal is 0 to 5 Vdc 0.5 to 4.5 Vdc for 0 bar and max pressure (bar) respectively
Solenoid Valve
Supplies control air into the unloader valve during loading Vent the control air trap in the unloader valve into the atmosphere during unloading. Supply voltage is controlled by elektronikon.
Regulating System – Load / Unload
Elektronikon
Monitor Compares feedback data against setting
Provides or cuts off electrical supply to solenoid valve
Unloading Assembly
Opens or close the air intake
Control air is coming through solenoid valve
Regulating System - Unloaded Y1 – Solenoid Valve is de-energized
Regulating System - Loaded Y1 – Solenoid Valve is energized
Proper Operation
Before Starting:
Check vacuum indicator, clean or replace air filter element if necessary
Check Oil level, top-up if necessary
Check belt condition if belt driven, retighten or replace if necessary
Check external condition of coolers, schedule servicing if necessary
Close the manual drain valve.
Proper Operation
During Operation
Check vacuum indicator, schedule replacement if necessary
Check pressure of oil separator if supported by the elektronikon
Check if automatic drain is working, schedule immediate servicing if malfunctioning.
Record the operating parameter data
Stopping the compressor
Push program stop button
During emergency cases, push emergency stop for the compressor to stop immediately
Open the manual drain valve
Monitoring & Inspection
Important Parameters
% RH = 14 to 26%
Pg = working pressure T out = Cooling air + 10 °C
T inlet < 40 °C Pg = 0 psi
Oil removal = 1 ppm
Oil removal = .01 ppm
Part removal = 1 µm
Part removal = 0.01 µm
PDP = 3 to 10 °C
Protections
Protection
Overheating protection
Element out temperature sensor – PT 1000
Trips at 110 °C (or 120 °C)
Over pressure protection
Delivery pressure sensor (for the new units)
Electrical protection
Can be set at Elektronikon module (1.5 bars above maximum working pressure MWP)
Safety Valve
Mechanical protection
Setting is 1.5 bars above MWP
Protection
Overload Protection
Located at load side, Phase current
Located at supply side, FLA
OL Setting, Phase = (FLA/1.73) x Service Factor OL Setting = FLA x Service Factor
Phase sequence relay (Optional)
Protect the motor against reverse rotation
Protect the motor against single phasing supply side
Protection
Short circuit protection
Circuit breaker
Ground fault protection
Circuit breaker
Elektronikon
Control and Monitoring System
Elektronikon ®
The hardware – compact electronic controller, microprocessor based, with a real time operating system – stabilized 24 V AC, wide voltage band power supply (-30% to + 40%) – ergonomic user interface (3xLEDs, easy to read alfa-numeric display, high quality push buttons)
Elektronikon ®
Reliability – controls and monitors compressor and integrated ancillaries – protects compressor and surroundings via automatic shut-down in case of a fault in a vital function – gives warnings well before shutdown, so proactive measurements can be taken
Elektronikon ®
Service friendliness
– monitors service intervals – generates service ‘WARNING’ messages – easy troubleshooting and fault-diagnosis
Atlas Copco Compressors
Proper Care
Proper Care – Compressor Elements
Air Filter
Must be maintained/replaced regularly
Oil
Right Quality is of utmost ut most importance
Non Foaming Property
Correct Viscosity Grade
Oil affects the lifetime of the bearings
Operating temperature
Proper Care - Main Drive Motor
Greasing
Frequency
Every 4,000 running hours or
Every 2,000 running hours
Quality
As specified in the manual manual and reflected in motor motor data plate Do not mix different type of grease
Quantity
As specified in manual or data plate if re-greasing is done every 4,000 running hrs
½ of specified quantity if re-greasing is done every 2,000 running hours
Proper Care - Main Drive Motor
Re-bearing
Every after 24,000 hours < 100 hp
Every after 40,000 hours > 100 hp
Proper Care - Operational Integrity
Compressor Room
Timely implementation of PMS
Ambient should not exceed 40 °C
Minimizes or reduced possibility of an expensive unscheduled shutdown Use of OEM Parts only
Electrical components must be audited or inspected every two years
Contactors
Overload Relay
Transformers
Wire & Cables including terminal connections
Air Filter
Air Compressor Oil
Oil Separator
Oil Filter
Atlas Copco
Preventive Maintenance Schedule
Types of Maintenance
Reactive/Breakdown Maintenance
Preventive Maintenance
Predictive Maintenance
Preventive + Predictive Maintenance
Practiced by Atlas Copco and Introduced through Service Plan Program
Compressor filtration system Oil Separator Air Filter
Oil Filter Air Compressor Oil
PMS: Preventive Maintenance Schedule
Every 2,000 hrs Change Oil Change
oil filter
Change
air filter
For
GX units: Replace oil separator
Change
drive belt/s for GX units & GA5GA10 units Grease
motor bearing (if not greased for
life) Servicing
of moisture trap
2,000 hrs PM kit is available
Every 4,000 hrs Repeat Change
2,000 hrs PM Oil separator for units up to 22 kW
(30 hp) Clean
the coolers externally if the condition demands
PMS: Preventive Maintenance Schedule
Every 6,000 hrs Repeat 2,000 hrs PM Change
Oil Separator for units bigger than 22 kW (30 hp) or Delta P of 1 bar across oil separator element if available (GA 55 & above) Ever y
12,000 hrs
Repeat 4,000/6,000 hrs PM Overhaul
Oil Stop Valve
Overhaul
Unloading/inlet valve
Overhaul
Minimum Pressure Valve
Overhaul
Check Valve
Overhaul
Moisture Trap
Clean
the coolers externally
Replace
thermostatic by pass valve
Replace
rubber coupling for non direct drive
units 12,000
hrs PM kit is available
PMS: Preventive Maintenance Schedule
> 24,000 hrs Repeat 12,000 hrs PM Overhauling
of compressor elements ( depend on SPM Reading for GA 30 up to 90C) Overhauling
of the drive
arrangement Re-bearing
of the electric motors
( SPM Reading) Re-conditioning
Internal
of electric motors
cleaning of oil cooler
Troubleshooting
Troubleshooting
Overheating: »
Causes, Prevention & Solution
Not Loading or Not Unloading: »
Systematic approach
Water & Oil Mixture in air receiver
Water in the Air System
High Oil carry-over: oil in the air system at receiver or end use
Air/Oil mixtures back-flow in Air intake filter element.
Electrical Failure:
Causes, Prevention & Solution
Troubleshooting
Compressor overheating
High ambient/room temperature
Very low oil level
Clog air filter
Clog oil separator element
Clog cooling fins of oil cooler
Oil cooler clog internally
Clog oil filter – insufficient cooling during unloading
Oil stop valve stuck up at close position
Thermostatic by pass valve stuck up at by passed position
Malfunctioning cooling fan motor & damaged cooling fan
Overheating Problem >40 °C
High ambient / room temperature
Very low oil level
Clog cooling fins
Oil cooler clog internally
Clog oil filter - OF
Cooling fins
Low oil level
OF
Oil cooler, internally
Overheating Problem
Malfunctioning cooling motor or damaged cooling fan
Clog air filter - AF
Clog oil separator
Oil stop valve stuck up at close position – OSV
Stuck up thermostatic by pass valve at by passed position – TBV
Oil separator
AF
OSV
TBV
Motor & fan
Troubleshooting
Scavenging Line
Excessive oil carry over
Wrong oil use
Clog scavenging line nozzle
Clog oil separator element, OS
Damaged oil separator Tank element, OS
Leaking o – ring & fittings inside oil/air separator tank
Internal condensation
OS
Oil
Clog OS
Troubleshooting
P < MWP Inlet or discharge
Compressor overloading
Clog oil separator element, OS
High operating pressure (should be less than the MWP)
Bearing problem for the compressor element – Inlet or discharge side
Bearing problem for the motor – Drive End or N Drive End
Leaking check valve CV – trip during starting
CV
Drive end or N Drive end
Troubleshooting
P sensor
Compressor not loading
Loading pressure setting is below operating pressure (with other units)
Malfunctioning pressure sensor
Upper solenoid valve plunger leaking
No supply voltage for solenoid valve SV
KO4 always open
Loose connection loading circuit
Open solenoid valve coil
Loose con. KO4 to SV
Upper plunger
Open coil
Supply voltage
KO4 inside module
P set
Troubleshooting
Compressor not loading
Open contact from KO4 relay (Elektronikon module)
Leaking switching valve & broken spring for unloading valve assembly
Inlet valve stuck up at closed position
Leaking loading piston seal ring and o-ring
Leaking pilot air line
Seal ring & o ring
KO4 inside module
Inlet valve Switching valve & Spring
Pilot air
Troubleshooting
Compressor not unloading/partial loading
High unloading pressure setting (with other units)
High plant demand
Air leak
Malfunctioning pressure sensor
Leaking lower solenoid valve plunger
Inlet valve stuck up at open position
Clog pressure sensor - air side
Pressur e sensor
Leaking plunger
IV Broken inlet valve Spring
spring
Plant deman d
Inlet valve
P settin g
Compressed Air Audit
Air Leakages
Moisture content & Relative humidity
Room Lay out & Ventilation
Restrictions on air filters, oil separator & line filters
Control
% RH = 14 to 26%
Pg = working pressure T out = Cooling air + 10 °C
T inlet < 40 °C Pg = 0 psi
Oil removal = 1 ppm
Oil removal = .01 ppm
Part removal = 1 µm
Part removal = 0.01 µm
PDP = 3 to 10 °C
Air Leakage
Air leakage and corresponding Power Consumption EQUIVALENT HOLE DIAMETER (mm)
1 2 5 10
AIR LEAKAGE @ 7 BAR (L/sec) (cfm)
0.9 3.6 22.5 88
1.9 7.6 48 186
Power Rate = PHP/kw – hr = 5
COMPRESSOR POWER REQUIREMENT ( Kw ) ( hp )
0.3 1.3 8.1 32
0.4 1.8 11 44
COST PER YEAR (PHP)
12,000 52,000 324,000 1,280,000
Water in Compressed Air System
Compressed Air Quality After AR – Wet Air
Delivery – Wet Air
Air Receiver , AR – Wet Air
Air Inlet – Depends on % RH at site
Dry Air, Design %RH = 15 to 26
Water in the system
Water entering the system = 39.286 g/m³ x 0.85 x 200 liters/s x 60 s/min x 60 min/hr x m³/1000 liters x 24 hrs/day = 577,032.768 g/day x liters/1000 g = 577.032768 liters/day ≈ 577 liters/day
Compressor with a working pressure of 7 bar (e), compressed the air to 1/8 of the volume.
7 bar (e)
How much water enter the system in liters/day?
Answer: 577 liters/day 577 l/day of water
Inlet: 35 °C, 85 % RH, 200 l/s
Water in the system
How much water separated at the air cooler °C
Answer = 437 l/day of water or condensates
How much water enter to the air net at a temperature of 45 °C?
Answer = 140 l/day of water or condensates At 45 °C (Tamb + 10) after air cooler, 64.848 g/m³
Inlet: 35 °C, 85 % RH, 200 l/s
How much water goes to the air receiver = 64.8 g/m³ x 90 m³/hour x 24 hrs/day = 139,968 g/day x liter/1000 g = 139.968 liters/day ≈ 140 l/day
577 l/day of water
140 l/day of water
Outlet: 45 °C, 100 % RH, 200 l/s, 7 bar (e)
How much water is separated = 39.286 g/m³ x 0.85 x 8 (P.R.) – 64.8 g/m³ = 202.3448 g/m³ x 90 m³/hr x 24 hrs/day = 437,064.768 g/day x liter/1000 g = 437 liters/day Or = 577 – 140 = 437 liters/day (at 35 °C, 85% RH, FAD of 200 l/s)
437 l/day of water
Water in the system
From the set up: Comp > Air Receiver > FD dryer
45 °C
7 bar (e)
109.45 l/day
How much water separated at the moisture trap of the Air Receiver in liters/day?
Water into the FD dryer = 50.672 g/m³ x 200 l/s x 3600 s/hour x 1/8 x m³/1000 l x l/1000 g x 24 hours/day = 109.45 l/day
Answer: 30.62 l/day
How much water enter the FD dryer in liters/day?
40 °C
Answer: 109.45 l/day
Condition: Air temperature going to air receiver, 45 °C = 64.848 g/m³, for a dT of 5 °C, the temperature of air leaving the air receiver is 40 °C = 50.672 g/m³
30.62 l/day
Solutions: Water separated at air receiver = (64.848 g/m³ - 50.672 g/m³) x 200 l/s x 3600 s/hour x 1/8 x m³/1000 l x l/1000g x 24 hours/day = 30.62 l/day
Inlet: 35 °C, 85 % RH, 200 l/s
32 °C
Water in the system
From the set up: Comp > Air Receiver > FD dryer
40 °C
How much water separated at the moisture trap of FD dryer
7 bar (e)
Water into air net = 12.86 l/day
32 °C
Answer: 96.59 l/day
How much water enter the air net (leaving the dryer) with a PDP or LAT of 3 °C?
Answer: 12.86 l/day
Water separated at moisture of FD dryer = (50.672 g/m³ - 5.953 g/m³) x 200 l/s x 3600 s/hour x 1/8 x m³/1000 l x l/1000g x 24 hours/day = 96.59304 l/day ≈ 96.59 l/day Water into the FD dryer = 5.953 g/m³ x 200 l/s x 3600 s/hour x 1/8 x m³/1000 l x l/1000 g x 24 hours/day = 12.85848 l/day ≈ 12.86 l/day
PDP = 3 °C
Inlet: 35 °C, 85 % RH, 200 l/s
Water sep = 96.59 l/day
Water in the system
32 °C
% RH ?
What is the relative humidity of compressed air leaving the dryer?
Answer: % RH = 18
PDP = 3 °C
Condition: % RH = (Actual moisture content, g/m³) / possible moisture content at given temperature, g/m³ x 100
Actual moisture at PDP of 3 °C = 5.953 g/m³ Possible moisture at given temperature of 32 °C = 33.490 g/m³ Solution: % RH = (5.953 g/m³) / (33.490 g/m³) x 100 = 17.17 ≈ 18 Note: Design Delta T between dryer inlet & outlet = 8 °C, 40°C – 8°C = 32°C
% RH = 18
Room Lay Out & Ventilation
Compressor Room Layout
Wall
A A Wall
A Compressor
A
A = 1000 mm, Minimum
Wall
Compressor Room Layout
Wall
A Comp 1
>A
>A A Comp 2
A A = 1000 mm, Minimum
Compressor Room Ventilation
Limit temperature rise to 5 °C
Maximum pressure drop of 30 Pa for ducting
Maximum length of 6 meters
Maximum bends of 2
Cross sectional area of ducting should be > the area of the base.
Ventilation air from coldest and cleanliest location
Ventilation requirements
Where:
Qv – Required ventilation capacity in m³/s
N – Shaft input of compressor in kw
dT – Temperature increase in compressor room in °C
dp max across ducting < 30 Pa
dT < 5 ˚C
Compressor
Compressor Room Ventilation
Installation of Pre Filter for dusty surroundings
Ventilation with louvers and grid multiply area by 1.7
Effective area is decreased to 60% with installed louvers
Ventilation Air Speed
Maximum air velocity through unrestricted opening is 5 m/s
Max T < 40 ˚C
Compressor
For motor cooling
Maximum air inlet temperature
40 °C High air intake temperature causes a decrease in mass fl ow
approx.3 % for each 10°C above normal ambient temperature, 0 % RH.
Material Specification
Committed to sustainable productivity.
