Post on 07-Feb-2018
transcript
1 Corporate presentation - june 2014
FULL POLYMER
HEAT-EXCHANGER TUBES
2
THERMAL PROPERTIES
Traditionally plastic profiles have only been known as excellent
thermal insulating parts, mostly in the construction industry.
But things have changed lately. The usage of highly conductive
graphite as a filler is now offering new dimensions in heat
conduction applications such as heat exchangers.
With the Technoform process it is possible to combine a high
degree of filler and an optimized orientation of the particles with
a smooth surface.
This polymer compound combination is able to achieve
similar heat conductivity values as stainless steel or
titanium.
* calculated out of practical heat transfer coefficient measurement, no direct measurement possible
** Measured on test rig under follwing conditions: Salinity 65g/kg, mass flow water 0,1kg/(s*m),
Temperature heating vapour 80°C, Temperature evaporation: 75,8 °C
THERMAL PROPERTIES OF PP-GRAPHITE
Heat resistance long term 90 °C
Specific heat capacity cp 1.21 J/(g*K)
Thermal elongation 29 x 10-6 1/K
Thermal conductivity in plane (injection moulding) 26.6 W/(m*K)
Thermal conductivity through plane (injection moulding) 4.5 W/(m*K)
Thermal conductivity through plane (extruded tube)* 10-15 W/(m*K)
Heat transfer coefficient on tube ** 2316 W/(m²*K)
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MECHANICAL PROPERTIES
of PP-Graphite
In general plastics have a wide range of properties and can be
adjusted to different requirements. The young's-modulus can
be adapted (depending on base polymer and reinforcement
fibers) in a range from 500 to 45000 MPa. A maximum tensile
strength of 330 MPa is possible. The softening-temperature
may be as high as 350°C (under 1.8MPa load).
TECHNICAL DATA
Density 1.56 g/cm³
Flexural-modulus 10400 MPa
Flexural strength (no yield) 49.5 MPa
Elongation 0.63 %
Roughness Rz (extruded tube) < 3 µm
Roughness Ra (extruded tube) <0.5 µm
Burst strength (1.5 mm wall extruded PP-GR tube) >5 bar
δ
X(t)
X0
t
T
PP has the advantage of having a high mechanical damping
factor: tanδ of 0.07-0.01 compared to 0.00002 for steel or
0.002 for copper.
This means system vibrations can be reduced by good
damping behaviour.
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INFLUENCE OF SURFACE ACTIVATION
on wetting behaviour
The polymer solution can be influenced
in its wetting behaviour. In their natural
state the tubes show hydrophobic
properties (see upper sample, right). But
with a special surface activation the
wetting can be increased to values
similar to Al-brass, thus ensuring equal
wetting on the outside.
Material Contact angle Θ
PP (untreated) 93.1°
PP (treated) 68.7°
Al-brass 63.3°
Θ In MED-plants this provides the option to
retain water repellent properties inside
the tube to initialize droplet conden-
sation, which leads to a massive
increase in the partial-heat-transfer
coefficient inside. In contrast, activation
enhances the wetting properties on the
outside.
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FOULING / SCALING BEHAVIOUR
Tests were carried out in a tank with a
spray nozzle system. Artificial seawater
(composition according to Kester et al.
with salinity of 65 g/kg) was used for the
test.
Test conditions: 4 weeks at system-
temperature 72°C (80°C water heating
inside); 4 tubes of each material stacked
in the tester; wetting of all tubes was
ensured.
The result show a much better fouling
behaviour with polymer tubes. The
deposition on polymer tubes can be
removed much easier by wiping. They do
not show the usual encrustation, which
leads us to the assumption that scaling
does not take place.
Reduced fouling/scaling leads to
lower costs due to fewer shut-downs
for cleaning processes as well as the
advantage of using less anti-scalants.
0,0 g/m
0,2 g/m
0,4 g/m
0,6 g/m
0,8 g/m
1,0 g/m
Al-Brass PA6-GR70PA12-GR70
PP-GR70
0.94 g/m
0.59 g/m 0.52 g/m 0.51 g/m
DEPOSITS ON TUBESURFACE [g/m]
Al-brass PP-Graphite
46% less fouling
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PARTICLE ORIENTATION is key to thermal conductivity
The special processing technology of Technoform allows the
alignment of particles relative to the extrusion direction. This
gives the heat transfer across the wall a remarkable boost.
The highest conductivity is achieved with an orientation-angle
of particles between 45° and 90°. We measured over 60% of
particles with an angle like this in our PP-Graphite tubes.
Over 60% with an angle
more than 45°
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THERMAL PROPERTIES in terms of fouling / scaling
Because of its fouling/scaling behaviour,
PP-Graphite tubes show their biggest
benefits after a certain time of usage.
After just 1000 hours of operation,
their heat transmission coefficient
equals tubes made of metal.
0
500
1000
1500
2000
2500
3000
3500
4000
PP-Gaphit Al Brass Alu Alloy 5052 Titanium
2316
2957 2998 2878
2.106 2.161 2.157 2.094
Ove
rall
he
at tr
an
sfe
r co
eff
icie
nt U
[W
/m²K
]
COMPARISON OF HEAT TRANSMISSION PERFORMANCE
heat transmission in fresh state estimated heat transmission after 1000h
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CHEMICAL RESISTANCE
Stainless steel Al-brass Al-alloy Titanium PP-Graphite
critical in dead
water (crevice
corrosion), temp
>45-85° and high
chloride
concentration
critical at temp
>70°
critical at temp
>50°, sensitive to
aerated water,
electrolytic
corrosion
Resistant to
seawater
Resistant to
seawater
Stainless Steel Al-brass Al-alloy Titanium PP-Graphite
Resistant to most
diluted acids
Resistant to most
diluted acids
Sensitive to acids Acid cleaning
unproblematic,
only hot acids may
attack material
Acid contact
unproblematic
pH-value of media
from 0-14 is
possible
Phosphoric acid
95%, Sulfuric Acid
90%, Hypochloric
acid >38%, Sodium
hydroxide >60%
Polymer-graphite compounds have no corrosion problems with high saline water even at
temperatures above 90°.
PP or PPS -Graphite compounds have outstanding chemical resistance against even
highly concentrated acids and bases.
SALT RESISTANCE / CORROSION
CHEMICAL (ACID-) RESISTANCE
9
0 0,5 1 1,5 2 2,5 3
PP-Graphite
Al-brass 2.99 kg CO2 per kg tube
0.78 kg CO2 per kg tube 74% less
CARBON FOOTPRINT
Adding all emissions of CO2, from mining and smelting/refining to
the final tube production, it becomes apparent that heat-
exchanger tubes made of PP-Graphite generate a 74% smaller
footprint than tubes made of Al-brass.
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COMPLIANCE
The polymer has a FDA certification and
all components have been confirmed not
to contain any substance with health
concerns related to drinking water.
Specific tests of the manufactured tubes
are under examination:
• Change of odour and flavour of water
• Change of the appearance of water
• Extraction of substances
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CONNECTING the heat-exchanger tubes For mounting a optimized connection
system should be considered. Possible
ways for a fitting could be
• Thermoforming (by heated
thorn)
• End-connectors with O-Ring
and fitting
• Insert in a Rubber gasket
(like in a drainpipe)
• Welding or bonding
THERMOFORMING
This technology can be used
for non-detachable
connections by beading the
end of the tube with a heated
or ultrasonic driven thorn.
END-CONNECTORS WITH
FITTING AND SEALING
The connector can be formed
with a thread or a self-locking
cone to press on a
rubber O-ring seal. It
combines good pressure
resistance and flexible tube
exchange.
INSERT IN A RUBBER
GASKET
The gasket connection offers
fast and simple connection
like in a drain pipe suitable
for applications with low
pressure difference .
WELDING OR BONDING
For compatible plastic plates
a welding connection with the
tube is possible.
For all other combinations we
recommend bonding. This
enables the safe connection
of different materials and also
provides sealing properties.
A proper bonding system
depending on materials,
temperatures and media has
to be chosen.
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SUMMARY & CONCLUSION
Plastics for the use in seawater-desalination plants form a
whole new material class.
They enable companies not only to realize a cost effective
system, but also to develop individual solutions, matching the
technical demands of the customers.
The freedom in design (of the geometry) in combination with
an outstanding corrosion behaviour and chemical resistance
provides a highly effective system.
Examples of possible geometries
A significant reduction in the use of process-chemicals (such as
anti-scalants and corrosion inhibitors) can be achieved by
utilizing polymer tubes. Furthermore, the wash out of heavy
metals (like copper), that may be harmful to the environment, is
eliminated. This might be of value for possible future regulations.
These properties in combination with the heat-transfer
technology developed by Technoform Kunststoffprofile
extends the possibilities for all heat-exchangers in the
future.
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MARKET LEADER
in extrusion of reinforced technical plastics
Technoform was founded in 1969
by Karl-Hans Caprano and Erwin
Brunnhofer as a family owned
business. Until today the company
has been directed by the families.
High degree of expertise in main
industrial sectors
Electro technology, mechanical
construction, automotive, aviation,
shipping, construction
Pushing the limits of possible
applications
Research and developement as key to
success e.g. thermal conductive
profiles, electrical conductive profiles,
high strength profiles, profiles for metal
substitution.
Continous growth over the past 40 years:
from 2 → 1500 Employees
from 1 → 40 countries (production and sales sites)
from 0 → 300.000.0000 € turnover p.a.
from 0 → 30.000.000 kg processed polyamide p.a.
Sebastian Ossadnik,
R&D engineer
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DRIVEN BY INNOVATION
Technoform Kunststoffprofile GmbH
Otto-Hahn-Str 34 | 34253 Lohfelden
www.tkp.biz | info@tkp.biz