Zero Emission Compressor Technology.

1. ZERO EMISSION COMPRESSOR SYSTEM
Ing. Guenter Kirsten
Istanbul / Turkey
kirstenguenter@gmail.com
Phone: 0090 507 6035013

2. Why the Initial worldwide Interest in Water Injection?
Water injected rotary screw air compressors have been developed to
provide an 100% oil free alternative to conventional dry compression
machines. Benefits include the obsolescence, or reduction, of
lubricating oils, a reduction in the number of system components,
increased energy efficiency and high pressure capabilities.
Who’s who in the WIS market?
Water injected rotary screw elements have been developed or
manufactured by seven companies:
• Atlas Copco (Poly-ceramic Rotors)
• GrassAir – Dutch (Poly-ceramic Rotors- hybrid)
• GVM – Germany ( Poly-ceramic Rotors)
• Mitsui Seiki – Japan (Monorotor Screw – hybrid)
• IHI – Japan ( Poly-ceramic Rotors - hybrid)
• SRM – Sweden (Poly-ceramic Rotors )
•Aerzener Maschinenfabrik Germany (stainless steel)
The History

3. Basic Principles
Why do we Inject Water into the Compression
Element?
Water is injected to cool, seal and lubricate the compression
element. This results in much lower compression temperatures,
nearing isothermal compression, and the associated increases
energy efficiency.
4 generic types of WIS elements are available worldwide.
Type 1 - The Pure WIS KIRSTEN
• No oil or grease is used as a lubricant in the machine
• Polymer ceramic rotors are fitted incl. bearings, produced
without shaft
• Hydro-dynamic/hydro-static bearings are fitted direct in
the Rotors accommodate axial and radial loads.
Type 2 - The Pure WIS ATLAS COPCO
• No oil or grease is used as a lubricant in the machine
• Polymer ceramic rotors are fitted
• Hydro-dynamic/hydro-static bearings are fitted to the
element to accommodate axial and radial loads.

4. Type 3 - The Hybrid WIS
•The compression element is fitted with oil or grease
lubricated bearings, or in combination with hydro-
dynamic /hydro-static bearings and shaft sealing's.
•Timing gears are used to synchronize the rotor motion
in applications where stainless steel rotors are used.
Type 4 - The Hybrid Mono Rotor Screw
WIS
• The compression element is fitted with grease
lubricated bearings
• A total of 6 bearings and shaft sealing’s are used
• Main rotor is cast iron, nickel plated and the
satellite rotors are a bronce with polymer material
Basic Principles

5. System Configuration and water tradement
What’s different?
Many factors can influence the final configuration of a water injected
screw air compressor and it need years of expirıence to handle the
water system under all climatic conditıons.
The main drivers include:
• Bearing configuration of element
• Element sealing
• Rotor material and profile
• Element casing material
• No use of timing gears
• No need of an after-cooler
• Water treatment system
• Inclusion of a start up water pump
• Material of pipe work and components
• Cooler material

6. Water Injected Screw Energy Efficiency
Water Injected Screw Technology the right choice
• Highly energy efficient
The higly effective cooling capabilities of water injection combined with pressision
engineering ensure that the water injected screw compressor is highly energy
efficient.
The nearer the compression process to Isothermal
compression the more energy efficient it becomes.

7. Why 100% Oil Free Air Oil removal
THE AIR QUALITY OF AN OIL LUBRICTED AIR COMPRESSOR IS
RELIANT ON THE SCAVINGE SYSTEM OF THE OIL SEPERATOR
An Orifice of 1 mm
diameter and the
seperator element is
the critical component
within this system
IF IT BLOCKS THEN THE
OIL SEPERATOR WILL FAIL
AND ALL THE OIL WILL BE
DELIVERED TO THE
COMPRESSED AIR
INSTALLATION

8. Why 100% Oil Free Air Oil removal
Do Not Accept any Compromise When it comes to
Production Efficiency, Quality and Safety
OIL CARRY OVER COSTS YOU MONEY YES
Do you accept ???
• Product contamination
• Contaminated fumes and condensate
• Increased energy cost
• Increased maintenance costs
• Increased maintenance down time
• Increased installation costs
• Increased floor space
• Environmental costs
• Dissatisfied customers
NO
Compressor 7 bar(e)
1 ppm = 1.2 mg/M³
Temperature of air °C
ResidualOilContentPPM

9. Why 100% Oil Free Air Activated Carbon Filters
Lifetime of active coal filters in function of temperature
NO USE AT AMBIENT
TEMPERATURES ABOVE 40°C
if you don’t cool down the
compressed air, or clean the
cooler on time it will make
problems quick.
An active coal filter
non-saturated absorbs the oil
vapor like a sponge
absorbs water
A saturated active coal filter no
longer absorb oil vapor just as a
saturated sponge
How do you know when
active coal is saturated?

10. Energy Efficiency Pressure Reduction
OIL INJECTED SOLUTION FOR INSTRUMENT AIR APPLICATION, USED ALSO İN VERY
SENSIBLE APPLİCATIONS LIKE HOSPİTALS, PHARMACY, ETC. IS ONLY A RISK.
Inlet valve
Check valve
Oil chamber and seperator
After cooler
Water seperator
dryer
oil removal
Filter
fine filter
active carbon
filter
Control point
Intake filter
Compressor element
New Lubricated
Compressor Seperator outlet Oil Filter Dryer Fine Filter Carbon Filter In System Total
7.7 Bar 0.2 Bar 7.5 Bar 0.2 Bar 0.1 Bar 0.2 Bar 0.3 Bar 6.7 Bar 1 Bar
Pressure
Drop
Pressure
Drop
Pressure
Drop
Pressure
Drop
PressurePressure
Pressure
Drop
Pressure
Pressure
Drop
Serviced Lubricated
Non Serviced Lubricated
8.5 Bar 1 Bar 7.5 Bar 1 Bar 0.1 Bar 1 Bar 0.3 Bar 5.1 Bar 3.4 Bar
8.3 Bar 0.8 Bar 7.5 Bar 0.5 Bar 0.1 Bar 0.5Bar 0.3 Bar 6.1 Bar 2.2 Bar

11. Energy Efficiency Pressure reduction
New oil Free
Compressor outlet Dryer In System Total
7,7 Bar 7,6 Bar 0.1 Bar 7,6 Bar 0.1 Bar
Pressure Pressure
Pressure
Drop
Pressure
Drop
Pressure
Serviced Oil Free
7,7 Bar 7,6 Bar 0.1 Bar 7,6 0.1 Bar
Non Serviced Oil Free
7,7 Bar 7,6 Bar 0.1 Bar 7,6 Bar 0.1 Bar
0 3000 6000
Operating Hours
Oil Free water injected
Compressor
Oil lubricated
Compressor
with Filters
80
90
100
110
120
130

12. Environmental Oil contamination
Water injected Screw Compressor
protects the environment by
eliminating oil in compressed air,
Conventional lubricated compressors generate a significant
amount of oil contamination within compressed air
- Disposal costs.
Increasing installation costs
Contaminating production processes
Incurring cost for condensate
treatment, Oil contamination damages the
environment and increases the cost of compressed air.
Installation and operating costs
can be significantly reduced, with the
purchase of a water injected compressor, by eliminating
the costly removal of oil and the necessity for
condensate treatment

13. Control and Monitoring Variable speed control 20 to 100%
0
10
20
30
40
50
60
70
80
90
100
0 12.5 25 40 50 60 75 80 100
FAD [%]
PC[%]
energy
savings
Traditional
KIRSTEN
The new Kirsten water injected screw compressor
has a permanent magnetic AC high speed motor
and can regulate the speed and power between 20
and 100%, which is the most efficient control
method worldwide for compressed air systems
with wide variations in air demand or systems that
require a very narrow pressure operating band.

14. Oil free adiabatic compression Screw and Tooth compressor
Two Stage Screw Compressor.
As to oil-free air compression with dry-running, adiabatic and oil-free screw compressors, an air end is generally
used in which two screw rotors, one male rotor with four teeth and one female rotor with six slots, are rotating along
each other like a gear mechanism. The first one rotates 50 percent faster than the latter. In order to achieve
acceptable efficiencies in this compressor system, very high speeds and, thus, circumferential speeds must be
performed. Speeds of the male rotor ranging from 80 to 120 m/sec. are normal throughout. So, the internal backflow
losses can be minimized and the final temperature controlled.
This also calls for special demands made on the bearings of screws and gears. The air is prevented to escape along
the rotor shaft by the use of special non-contact labyrinth seals. Other seals prevent any ingress of oil from the rotor
bearings into the compression chamber. A two-stage configuration with intermediate cooling is required for a final
temperature of 6 to 10 bar. The temperatures come up to 180°C per stage at an intake temperature of 20°C. The
greatest advantage of these compressors is the level of popularity as for the ZR compressors of Atlas Copco which
held a unique position for years. When viewing the "flow chart", the significance of oil in these "oil-free" compressors
can be easily discerned.
Oil is needed for lubrication of the synchronous gears in both stages, the bearing and gear transmission. To ensure
availability of such oil in a closed circuit, cooling by means of a cooler must take place. An air-oil collector is
integrated in the gear venting system as leakage air permanently enters into the lubrication circuit through the
labyrinth seals. Escape of oil and oil vapors cannot be prevented. Further, this features an additional maintenance
interface with required disposal cost. Notwithstanding the shaft seal, oil may enter from the bearing side into the
compression chamber a phenomenon that is not immediately discerned, in particular, in idle run of these
compressors as there is a distinct under pressure on suction side due to the closure of throttle valve. This results in
oil-containing compressed air the segregation only being possible by means of expensive filter combinations due to
the high temperatures. In factories where highest quality demands are made on compressed air, it is indispensable to
use superfine filters.
This compressor system needs three high-value coolers: intermediate cooler, after cooler and oil cooler. According
to experience, sediments and wearing in the coolers after approx. 10,000 hours of operation are frequently incurred.
Periodical cleaning of all the coolers with the need of dismounting work is absolutely required. This gives rise to
enormous wage and material cost. Condensation water deposition in the intermediate cooler is also of particular
importance, all liquid parts should be segregated as this condensation water is acid i.e. aggressive. Coating of rotors
to minimize corrosion and friction as well as possible contact due to the increased compression temperature is also
very important.
This coating, normally PTFE, gradually peels off. Consequently, backflows are produced within the stage causing a
reduction of the rate of delivery by up to 15 percent i.e. to ensure availability of the full rate of delivery, by 15 percent
higher energy cost must be spent. Even in case of high-quality coatings, losses in the rate of delivery of at least 5
percent may still occur. This wear already occurs after 2,000 to 4,000 hours of operation. That is why a fine filter
should be installed in the pressure line of dry-running screw compressors to extract the abrasion particles. Generally,
maintenance, inspection of repair of these packages must be performed by shop experts only. Difficulties are
particularly expırienced in control and regulation features which can be adjusted correctly only with plenty of
experience. Contamination or overheating of packages will cause substantial damages in the air ends. Replacement
as well as repair costs are very high.

15. Oil free adiabatic compression Screw and Tooth compressor
Two Stage Tooth Compressor
In order to achieve acceptable efficiencies in this compressor system, very high speeds and, thus,
circumferential speeds must be performed. Speeds of the male rotor ranging from 60 to 100 m/sec. are
normal throughout. So, the internal backflow losses can be minimized and the final temperature
controlled. This also calls for special demands made on the bearings of In most cases, the male rotor is
driven by a gear transmission whereby the male rotor drives the female rotor via synchronous gear
mechanism. Mechanical contacts of tooth flanks are excluded.
A small gap dimensioned to the operating temperature of compressor is provided in between the rotor
surfaces. rotors and gears. The air is prevented to escape along the rotor shaft by the use of special non-
contact labyrinth seals. Other seals prevent any ingress of oil from the rotor bearings into the
compression chamber.
A two-stage configuration with intermediate cooling is required for a final temperature of 6 to 8,5 bar.
The temperatures come up to 180°C per stage at an intake temperature of 20°C. The greatest advantage of
these compressors is the level of popularity as for the ZT compressors of Atlas Copco which held a unique
position for years.
When viewing the "flow chart", the significance of oil in these "oil-free" compressors can be easily
discerned. Oil is needed for lubrication of the synchronous gears in both stages, the bearing and gear
transmission. This compressor system needs three high-value coolers: intermediate cooler, after cooler
and oil cooler. According to experience, sediments and wearing in the coolers after approx. 10,000 hours
of operation are frequently incurred. Periodical cleaning of all the coolers with the need of dismounting
work is absolutely required.
This gives rise to enormous wage and material cost. Condensation water deposition in the intermediate
cooler is also of particular importance, all liquid parts should be segregated as this condensation water is
acid i.e. aggressive. Coating of rotors to minimize corrosion and friction as well as possible contact due to
the increased compression temperature is also very important. This coating, normally PTFE, gradually
peels off. Consequently, backflows are produced within the stage causing a reduction of the rate of
delivery by up to 15 percent i.e. to ensure availability of the full rate of delivery, by 15 percent higher energy
cost must be spent. Even in case of high-quality coatings, losses in the rate of delivery of at least 5 percent
may still occur. This wear already occurs after 2,000 to 4,000 hours of operation. That is why a fine filter
should be installed in the pressure line of dry-running tooth-type rotary compressors to extract the
abrasion particles.
Generally, maintenance, inspection of repair of these packages must be performed by shop experts only.
Difficulties are particularly experienced in control and regulation features which can be adjusted correctly
only with plenty of experience. Contamination or overheating of packages will cause substantial damages
in the air ends. Replacement as well as repair costs are very high.

16. How many water is in the compressed Air of a water injected
compressor? Absolute the same then in all other
compressors.
This diagrams show how many water
is in the air under different
conditions, pressure and temperaturs.
All compressors that compress Air
has the same content of water . Water
can only reduced by coolıng and
drying of the pressed air with a
refrigeratıon, absorbtion or
adsorption dryer, this is up to the
process what the costumer need.

17. How to handle the water tradement internal the system and
from external?
The Water tradement and cleaning system is the
importants device in a water injected compressor.
Atlas Copco and all other use a Reverse Osmosis
System to clean the drinking water and fill it in the
machine when the water level is low. This is sure not
enough to control the water quality in the compressor
system. The water system is not a closed system. The
air that coming in from the atmosphere bring a lot of
bad ions in the system, the water wash all this out and
now the ions are in the water system. Further the
water ever take ions from the material inside the
system, and try to find balance .
A real water tradement has to messuring and clean permanently the
water system. Only the from Kirsten patented system can do this and
give the absolute security under all conditions that the water quality
in the machine is around the world the same. 30 years of expirience
with water lubricated and water injected screw compressors has
shown the way how to do this. When the water in the compressor
system is regulated between a conductivity from 5 to 10 micro
siemens by 20°C, the system runing under safe conditions, water
lubricated bearings life time will more then 50.000 hours.

18. What are the benefit to use the NEW water injected screw
compressor technologie?
The Maintenance Engineer
The oil in compressed air after
compression will attack
downstream equipment, causing
increased maintenance
requirements and increased
plant downtime
The Financial Manager
Low cost oil lubricated
compressors may look attractive,
But when considering the total
operating costs compared to Oil
free compressors, the extra
investment in a water injected
screw compressor will easily pay
for itself
The Application Engineer
Every application can benefit from
oil free air compressors with total
product safety, lower operating,
and maintenance costs and a
healthier working environment
The General Manager
If you require maximum reliability
and energy efficiency to improve
your total operating costs, The
ZERO EMISSİON SCREW
COMPRESSOR provides you with
the optimum compressed air
generation solution without any risk
The Safety and Environment Manager
Breathing oil fumes is definitely not a good
idea and oil Condensate can damage the
environment So why do it the hard way,
when you can do it the smart way with oil
free water injected compressors
The Quality Manager
Do not accept the possibility of
product contamination, and reduced
product quality. Only 100% Oil free
compressors can offer a 100%
Guarantee of Oil Free Air