2015 11-19-energy efficiency efficient use of raw materials

Detlev Matzdorf, Nov 2015, Sirris, Gent
Welcome to Sirris
workshop: Energy efficient peripherals and ancillaries
in plastics processing
Gent Meeting Center, Nov. 18th 2015
Subject: Energy efficient use of raw materials
Speaker: Mr. Detlev Matzdorf
motan-colortronic GmbH
Otto-Hahn Str. 14
D-61381 Friedrichsdorf

Energie efficient use of raw materials
Where to save energy in the material handling process
- Where to save energy in the material storage process
- Where to save energy in the drying process
- Where to save energy in the conveying process
- Where to save energy in the dosing process
- Where to save energy in motor design

Where to save energy in the handling process
If possible, heat the
material on the
machine material inlet
Prevent the
material from
re-moisturing
Preheating the
silo with
exhaust heat
Use the right drying
parameters (airflow,
dew point, temperature
and residence time )
for your application.
Dryer
Bin Bin
Octabin
M
Moulding M.
Outdoor silo
Improve the efficiency
of the screw drive
of the moulding
machine
Prevent the material
from recooling
Convey the material
energy efficient

Parameters which influence energy consumption
1. Summer – Winter
changing ambient humidity
changing material temperatures
2. Changing humidity in material supply.
3. Changing drying parameters
- temperature difference between drying temperature
and return air temperature
- dew point for material drying
- material data (cp value) related to specific dry air flow
- changing demand of the connected machines
4. conveying process
5. use of right motors ( please refer to the lecture of
Kurt Muylaert, Danfoss)

1. Initial moisture in granules, Summer – Winter relation
Spring Summer WinterAutumn
Moisture content of the material in relation to
the season
Required rest humidity for production
If plastic granulates are stored in ambient air, it always adapts to the moisture content of the
environment until the moisture of the material and environment is equal.

The specific air flow rate must be adapted
to the material inlet temperatures!
The colder the material, the more air
and energy is needed, in order to
heat up the material to a final
temperature.
Example: In order to heat up a material in
winter time from –10 °C to 175 °C with a
constant exhaust air temperature of 62 °C,
we need a specific dry air flow of 2.7 m³/kg
and 104 Wh/kg of energy will be consumed.
Same case in summer : at 20 °C material
inlet temperature, 2.27 m³/kg air flow will be
sufficient to heat up the material to
175 °C, with an energy consumption of
88 Wh/kg with an exhaust air temperature
of 62 °C.
1.1. Material inlet temperature in relation to the
specific air flow and the energy consumption
1,8 1,92 2,05 2,18 2,30 2,43 2,55 2,68 2,80
Specific dry air flow [m³/kg]
Energy usage and specific dry air flow in relation to the material inlet
temperature
-20
-10
0
10
20
30
40
50
70 75 80 85 90 95 100 105 110
Energy usage [Wh/kg]
Material
inlet
[°C]
Autumn / Fall
Summer
Winter

Dryer
Bin Bin
Octabin
M
Processing machine
T1a T1b
T3
T4 T5
T2
0,2%
0,4%
0°
0,5%
Delivery of pre-
dried material
Winter
Summer
Re-moisturing
dependent on the
storage time and
ambient moisture
More or less drying
performace required
T2T1 T4 T5
Re-moisturing
dependent on the
storage time on the
machine bin
Outdoor silo
T0
T3T0
0,3%
0,1%
Note : Drying systems are always rated for the worst case of maximum material
moisture, minimum inlet temperature and maximum throughput. Solution is: ETA²
1.2. Re-moisturing of the material in a standard production

- Prevent the material from re-moisturing!
The material stays for hours or weeks in the outdoor silo or other storage vessels. Keep the
material in a dry environment.
- For every % of moisture the material absorbs, you have to spend another 25 Watt hours/kg to
remove it!!
Dry air
generator
Outdoor silo Use exhaust heat
from production
2.2. Prevent material re-moisturing in the outdoor silo or
octabin.
Dry air quantity for blanketing
per m³ silo volume = 1m³/h dry air flow

2.3.1. Efficiency of material heat up of heating with hot air
in comparison to heating up by friction by the screw.
Example: to heat up material from 40°C to 120°C we need energy:
- by using friction : 1 kg x 1,2 kJ / kg K x 80°K / 0,49 efficiency / 3,6Wh / kJ = 54,4 Wh/kg
- by using hot air heat up with electric heater : 1 kg x 1,2kJ/kg K x 80°K /0,8 Wirkungsgrad /3,6Wh/kJ = 33,3 Wh/kg
By heating the material on the machine from 40°to 120°C the energy consumption can be
reduced by 38.8 % only for this part of process.
ProcessingE-Motor
Hydro-
drive
= Efficiency
E-Motor
= 0,85
Hydro pump
= 0,80
Tubes and
Valves = 0,90
Hydro drive
= 0,80
Total efficiency for
heating with electrical
heater incl. blower = 0,80
Total efficiency for
heating with friktion = 49%
( 0,8 x 0,9 x 0,8 x 0,85 = 0,49 )

2.3.2 Small application of material drying on the machine
M
Moulding
Dryer
Bin
Re-cooling of the
material due to
conveying and storing
in the machine hopper
Dryer
Bin
M
Moulding
Heat exchanger
Heater
No loss of
heat
100°
200°
0°
250°
T1a Winter
T1a Summer
T1
T2
Cooling by
conveying
with cold
ambient air
Cooling by storing
the material in the
machine hopper
T3 T4 T5
Heating to
230° by
friction and heating
LOSS
Drying
phase
100°
200°
0°
250°
T1a Winter
T1a Summer
T1
T2
Material gets hot
by drying
T4 T5
Heating to.
230° by
Friction und heating
No conveying
no cooling
T2
T2
T4
T4
T5
T5
T3
T1
Winter /
Summer
Drying
phase
With two conveying steps we need approx. 10% of specific energy use for
conveying

2.4 Energy consumption comparison of drying Nylon PA 6
The comparison of the energy usage shows the real benefit of a conditioning process at 60°C with reduced
airflow for Nylon in relation to standard drying at 80°C and full airflow.
- No over-drying or too wet material
- only half size dryer needed and application with low air flow
Energy calculation comparison
Standard drying
at 80°C
Conditioning at
60°C
Material throughput: Kg/h 500 500 Kg/h
Dry air generator LUXOR 1200 600
Dry air fow with ETA plus 950 450 m³/h
Energy usage of a drying system for PA 6 63,2% % Savings
Energy consumption of the system 15,3 5,6 kW
Spezific energy usage = 30,5 11,3 Wh/kg
Cost in Cent / m³ dry air 0,1608 0,1250 Euro Cent / m³
Total cost in 8000 h per year 12219,44 4500,70 Euro/year
Standard drying at
80°C
only conditioning at 60°C
Blower 9,7 5,2
Heater 11,7 3,0
Regeneration 9,2 3,0
0,0
5,0
10,0
15,0
20,0
25,0
30,0
35,0
Standard drying at 80°C only conditioning at 60°C
Energyusage[Wh/kg]
Energy usage of drying or conditioning of PA 6
Regeneration
Heater
Blower

3.1. Desiccant bed dryer with automatic
energy saving technology
- Preheating of regeneration air
with heat exchanger
Reduction of energy usage
- Temperature controlled
regeneration
Energy efficient load related
heating process
- Dew point control Reduced quantity of regeneration
Cycles = energy saving
- Insulated desiccant bed Reduced heat radiation during the
heat up phase
Drying process:
- Frequency controlled
process air blower
Enables load-related energy
consumption
Regeneration process: Advantages:
- Return air controlled
dry air flow
Best way to control the energy
requirement of the drying process
- Dew point control Defined maximum process dew point

3.2. Elements of ETA plus drying process
ETA plus AFC frequency
controlled drying process
blower.
Measurement of the
exhaust air °C, °F
Difference pressure
measurement
Motor valve on every
drying bin
Optional ETA plus heat exchanger
for high temperature and high
airflow solutions
Heater close to the bin air
inlet
M
Heat exchanger for
regeneration air heating up
Dew point controlled
regeneration bed switch
cycles
Separated bed switch
valve blocks for
minimum heat loss
Fully insulated drying bin
Closed loop recooling with active
cooler, in order to prevent the
desiccant bed from re-moisturing.
Up to 30% more dehumidification
power in comparison to ambient air
recooling
Fully separated process
air circuits for regeneration
and material drying
motan

Temperature profile in drying systems with and without ETA plus heat exchanger
Drying temperature (°C)
Blower
Trockentrichter
Dryer
Material
Heat
reclamation
25%
Heat
exchange
return air
Dry
air
heating
Heat
exchange
process air
Molecular
sieve
Air / air
aftercooler
200°C / 392°F
0°C / 32°F
180°C / 356°F
160°C / 320°F
140°C / 284°F
120°C / 248°F
100°C / 212°F
80°C / 176°F
60°C / 140°F
40°C / 104°F
20°C / 68°F
3.2.1. Comparison of drying systems

In drying systems it frequently occurs that the material throughput in
the drying process is changed due to tool change or switching off
some cavities
What would be an intelligent reaction to changing material
throughputs in the drying bin?
Should we lower the level in the bin to keep the residence time
constant?
Should we reduce the air flow?
Should we… ??
3.3. drying process with automatic air flow control

The ETA plus air flow control is an automatic system for efficient regulation
of the air flow and drying temperature in every single drying bin related to the
material throughput.
Main criteria:
• Reduction of the energy consumption by adjustment of the airflow
and drying temperature to the material throughput
• Material-protective drying procedure
(avoiding material damage by drying for too long)
• Adaption of the drying performance to different material inlet
temperatures: Summer / Winter - Day / Night
3.4. Main criteria for the automatic airflow control ETA plus

MM
mo
t
anME
T
R
O
mo
t
anME
T
R
O
12
3.5.1. Main elements of the air flow control
Frequency controlled
drying process blower Hz
Measurement of the
exhaust air temperature
°C
Measurement of pressure
difference between process and
return air
Motor valve for air
control on every drying
bin
Today the air flow control is regarded as the most important system
to adapt the energy consumption of the drying process to the
material drying requirements!
NOTE: The main set value for air
flow control is the return air
temperature at the drying bin.
For 71 materials, a default value of
the return air set value is stored in
a data base.
Normally the return air set value is
around 45% of the heating
temperature.

3.5.2 Coherence of air flow and temperature control
20
40
60
80
100
120
140
60
80
100
120
140
0102030405060708090100
Material throughput [ % ]
Temperature°C
Air flow %
Air flow
[ % ]
Drying-
temperature
[ °C ]
50°C
120°C
50°C
120°C
100 kg/h200 kg/h
mediumhigh
50°C
108°C
50 kg/h
low
65°C
80°C
0 kg/h
lowAir flow
Heater temp.
Exhaust
air temp.
Material 20°C Material 20°C Material 20°C No Material
The new ETA plus
process includes a
combined air flow and
temperature control for
maximum energy
efficiency and safe
material drying.
Motan ETA plus drying
system guarantees
maximum of energy
effectivity and at once
safety against material
damaging or over drying

3.5.3. Results of changing the material throughput
without adjusting the drying parameters
Energy balance:
If more energy is supplied than
removed, the temperature
gradient moves to the top of the
silo!
Consequence: High exhaust air
temperatures, long residence
time at high temperatures
= material degradation!
A lot of cooling energy is
needed to cool the hot exhaust
air for dehumidification in the
dryer!
= Not a good solution!
Return air
temp. 62
°C
Material IN
20°C
1000 kg/h
Heating temp.
175 °C
2280 m³/h
Energy
usage
88 Wh/kg
Material
outlet temp.
172°C
Return air temp.
108 °C
Material IN 20 °C
600 kg/h
Heating temp.
175 °C
2280 m³/h
Energy
usage
137 Wh/kg
Material
outlet temp.
175 °C
Reduction of the
material throughput

3.5.4. Best solution with air flow control at full bin level
Maximum material level
and air flow control
Return air
temp. 108
°C
Material IN 20
°C
600 kg/h
Heating temp.
175 °C
2280 m³/h
Energy usage
79 Wh/kg !!
Return air
temp. 55
°C
Material IN 20 °C
600 kg/h
Heating temp.
175 °C
1230 m³/h
10h
4h
Energy usage
137 Wh/kg
Lower air temperature reduces the
cooling water requirements of the drying
process.
No material degradation, because in
the last 4 hours only the temperature
is above 120 °C!
Through improved efficiency, the air
flow can be reduced to 1230 m³/h.
The full bin causes a 66% larger
heat exchange surface between
bulk material surface and dry air
for material heat-up!
No material center flow!

3.5.5. Best solution with air flow control at full bin level
Summary:
What to do with variable material throughput?
1. Do not reduce the material level!
2. Full bin for better heat transfer!
3. Using the Eta+ air flow control!
4. Avoid expensive equipment!
5. Reduced energy consumption from 137 to
79 Wh / kg = 42%!!
Energy usage
79 Wh/kg !!
Return air
temp.
55 °C
Material IN 20°C
600 kg/h
Heating temp.
175 °C
1230 m³/h
10h
4h

Motor Motor
Pressurized
+ -
T1LMR T2LMR
T3LMR
Air flow process air
Air flow process return air
Motor
by blower
Filter
Desiccantbed
The diagram shows a drying
system with dryer and 2x 600
liter and one 300 liter drying bin.
The blower generates the air
flow in the system, in order to
get a constant pressure in the
process duct work.
At every drying bin a throttle
valve is installed to set the
airflow to the right level.
Throttlling Throttlling
Pressure
drop in the
bulk
Pressure
drop in the
bulk
90%
45%
45%
Pressure difference
measurement between
process and return air
3.6. Diagram of a multiple bin drying system
with air flow control
Heater
Air flow meter

The comparison was carried out for PET drying systems. With variable material
throughputs, the range of energy saving can be from 24% to 64%.
3.7. Comparison of systems with ETA plus air flow control
and systems without energy saving features
0,00
10,00
20,00
30,00
40,00
50,00
60,00
70,00
1 2 3
Energyusage[kW]
Material flow [ kg/h ]
Energy usage of ETA systems with air flow
control
260 390 520
Regeneration energy
Blower energy
Energy savings
Heating energy
0,00
10,00
20,00
30,00
40,00
50,00
60,00
70,00
1 2 3
Energyusage[kW]
Material flow [ kg/h ]
Energy usage of drying systems without
energy saving features
Heating energy
Regeneration energy
Cooling Energy
Blower energy
260 390 520

3.8. Energy usage for drying of ABS with a LUXOR 120
In comparison to a conventional drying system you can save app. 35% to 50% of the
energy consumption by using a ETA plus drying system.
Even with a small LUXOR 120 savings of up to 900 Euro / year can be realized easily.
0
10
20
30
40
50
60
70
80
90
40 45 50 55 60 65 70 75 80
EnergyusageWh/kg
Material throughput kg/h
Energy usage of a LUXOR A 120 for ABS
with Eta plus and conventional
ETA plus ABS
Konv. ABS
ABSETA plus
ABSconventional
20,0%
30,0%
40,0%
50,0%
60,0%
40 50 60 70 80
Energysaving%
Material throughput kg/h
Procentage of savings of
LUXOR 120 with ETA plus
Specific energy usage! Wh / kg Absolute energy usage = kW

Reduction of energy consumption in the
regeneration process by drying with
adequate dew points
Low dew points costs a lot of money!

3.9.1. The regeneration process
Additional features that reduces the numbers of
regeneration cycles:
- Dew point controlled regeneration
-Constant dew point regulation ATTN
-Closed loop re-cooling
Features that reduces the energy usage directly:
-Temperature controlled process steps
-Heat exchanger in the heat up loop
How to optimise the regeneration process?
1. Use of sufficient dew point set value  increased water intake of the desiccant bed
2. Goal: Increased water intake of the desiccant bed  reduced numbers of regeneration cycles
3. Reduced numbers of regeneration cycles  lower total energy consumption

Drying with adequate dewpoints and not with the lowest possible dew point!
An adequate dew point can increase the drying capacity by 133%!
Dew point
Dry air temperature (molecular sieve temp. = process - return air)
Water adsorption
With a maximum
dew point of –40
°C only 6%
adsoption
With a maximum
dew point of –20
°C 14% adsoption
-50 °C / -58 °F
-40 °C / -40 °F
-30 °C / -22 °F
-20 °C / - 4 °F
50 °C
122 °F
150 °C
302 °F
200 °C
392 °F
100 °C
212 °F
250 °C
482 °F
3.9.2. Reduction of energy usage by using
sufficient dew points

Reduction of number of regeneration cycles leads to 20% energy savings by
the use of higher, but sufficient dew points
Energy consumption with different bed switch cycle
times
800
850
900
950
1000
1050
1100
1150
1200
3 4 5 6 8 10 12 14 16 18 20 22 24
Bed switch cycle time ( 6 . . . 24 hours )
Totalenergyconsumption
(KWperday)
Reduction of 225
KWh per day
By changing the
maximum dewpoint
from -40 to -20 °C it
was possible to reduce
the total energy costs
of 20% - only by
increasing the bed
switch cycle time.
From 3 to 10 hours.
The test was carried through at
IFAP in Italia.
3.9.3. Reduction of regeneration cycles saves energy

3.10 Automatic constant dew point
control ATTN for drying systems

3.10.1. Quality losses by over- and under-drying
Moisture content directly affects the viscosity of the melt:
- If the residual moisture is too low, this leads to a tough melt, which increases shearing
in the material and causes a higher drive power of the machine. That leads thereby to a
material damage and to a reduction of the intrinsic viscosity.
- A too high moisture content in the melt phase lowers down the friction, but increases
hydrolysis and also leads to a material damage and to a reduction of the intrinsic
viscosity.
- Only with optimal humidity content the damage is low.
low Moisture content Too high
Degree of
damage
Damage through
friction due to too
tough melt
Damage by vapour
through hydrolysis
Optimum
moisture
content

min. moisture 0,03 0,03 0,03 0,03 0,03 0,03 0,03 0,03 0,03 0,03 0,03
Drying of NORYL GTX at production ( from 2,5 h) up to standby ( >> 2,5 h)
0
0,05
0,1
0,15
0,2
0 0,5 1 1,5 2 2,5 3 3,5 4 4,5 5 5,5
Drying time [h]
Residualmoisture[%]
- 15 °C / 100 °C production
Eta plus on mimimum
- 5 °C / 60 °C standby
Eta plus on maximum
max. moisture
min. moisture
3.10.2. Procedure of the constant dew point control
The combination of ATTN and ETA plus enables a safe drying process.
ATTN avoids material from over drying.
ETA plus function controls the drying speed related to material throughput.

Conventional systems
0 1 3 7
-10
-20
-30
-40
T (c°)
t (h)
Motan dew point control
0 1 3 7
-10
-20
-30
-40
T (c°)
t (h)
Overdrying is effectively avoided!
- Low shear rate of the material melt by uniform water content below 30 ppm.
- Reduced degradation of the material = less AA value
- Lower power consumption of the production machine = energy savings
 Advantage of an adjustable dew point!
3.10.3. Automatic constant dew point control
14 °F
-4 °F
-22 °F
-40 °F

Dew point in relation to the bypass position
Set dew point -15 °C / 5 °F
Fresh desiccant bed Wet desiccant bed
Dew point control with a
valve positioned in front of
the desiccant bed .
This valve mixes return air
and dried air to process
air with a constant dew
point .
3.10.4. Automatic constant dew point control
32°F
5°F
-22°F

Kapitel 1 Grundlagen der
4.1 Material conveying systems

4.1. Material conveying systems
- conventional central vacuum systems
 grown factories with additional maschines
 different vacuum systems for different machine lines
 Vacuum pumps with fixed speed
- Advantages of conventional central vacuum systems
 step by step installation with growth of factory.
 low investment costs for small throughputs
- disadvantages of conventional central vacuum systems
 power loss due to blower after-run, switching on/off, current peaks during
start-up of the blower
 only one hopper loader can be served at one time
 large number of installed vacuum pumps and filter
 required maintenance for large amount of blower

4.2. material gentle conveying for
reduction of material degregation and
reduction of energy consumption of
vaccuum pumps

model comparison
Car driving material conveying
always full speed blower / pump ON/OFF
accelerator pedal
cruise control
Speed adjustable pump
Airflow - control
4.2.1 material gentle conveying

Strong differences in pipe
lengthes of material-lines
the air speed will be automatically
controlled independently of line
resistance
conveying with controlled conveying velocity
4.2.4 material gentle conveying

simple operation
1. one-time configuration at initial start up,
2. On demand fine trimming and saving of pump speed
during operation with + - buttons; D Rohr mm 45
4.2.6. material gentle conveying
reduced energy consumption for conveying
energy consumption increases with the conveying velocity quadratically !
Q = density x velocity² / 2
therefore: even small speed reductions bring significant energy savings!
•reduced wear on pipes, elbows, hopper loader
• reduced maintenance and repair costs
• reduced material degregation ( angel-hair, dust )
speed + -

1. Connection hopper loader – vacuum line
2. Raw gas line
3. Central filter
4. Clean gas line
5. Frequency controlled vacuum blower
6. Control for permanent central vacuum
4.3.1 permanent central vacuum

4.3.2 Example of existing installation
Various Examples
Rehau / Visbek

Example of a floor plan
Big Safety Filter with 29 m² filter surface
Frequency controlled blower up to 18.5 kW

- Field of application for a permanent central vacuum system
 High conveying performances (long distances, high number of consumers)
 Air volumes of approx. 800m³/h – 18.000m³/h
- Advantages of a permanent central vacuum system
 Generation of vacuum depending on the consumption and therefore energy
savings up to 30 - 50% compared to a standard central conveying system
with line blowers
 High conveying performances due to the fact of simultaneous conveying of
severals hopper loaders
 Reduced power loss due to no blower after-run, no switching on/off, no
current peaks during start-up of the blower
 Significantly simplified maintenance due to the fact of less installed blowers
and filters

5. use of right motors
- use of right motors ( please refer to the lecture of
Kurt Muylaert, Danfoss)
Please remember for future installations or revamping
purchasing costs of a motor cover only 2 – 3 % of the overall lifetime costs
due to energy demand.
A motor with demand oriented control will pay off within a short time.

Contacts
interested in more Details ?
Please contact
ORA Machines N.V.
Mr. Philippe Philips
Ambachtenzone Haasrode 3301
Ambachtenlaan 35
BE-3001 Heverlee
info@ora.be
+32-16-400-383
Kapitel 1 Grundlagen der

Thank you for your attention !

2015 11-19-energy efficiency efficient use of raw materials

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