KOENST
Renewable energy-efficient plastics production technologies
Granular Preheating
VS.
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Renewable energy-efficient plastics production technologies
300000
700000
250000
600000
Gas consumption [MJ]/dag
Electricity [kWh]/dag
Motivation
Electricity Consumption
Gas consumption
500000
200000
400000
150000
300000
100000
200000
50000
100000
00
2
KOENST
Renewable energy-efficient plastics production technologies
Motivation
Heat
(140 ⁰C)
Heat
(60⁰C)
Heat
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KOENST
Renewable energy-efficient plastics production technologies
How could we reuse the hot air?
Hot air (contaminated with paraffines)
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KOENST
Renewable energy-efficient plastics production technologies
SHS
Preheater model
1. Build for one specific plant situation
2. Performed practical tests
Windesheim
Computermodel
1. To optimize preheater model SHS
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2. Find most optimal configuration in other plant situations
KOENST
Renewable energy-efficient plastics production technologies
Computer simulation model
Plan
1. Practical testsetup → validation Computer model
– Collect data for different configurations
2. Collected data serve as input for Computer
simulation model
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KOENST
Renewable energy-efficient plastics production technologies
Methodology
Testsetup: simplyfication of model used at SHS
1. Preheater
2. Control & Recording
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KOENST
Renewable energy-efficient plastics production technologies
Preheater
1.
2.
3.
4.
5.
The frame
The Silo
Bunker
Screw pump
Hot air input
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KOENST
Renewable energy-efficient plastics production technologies
Control & Recording
labVIEW
ANSYS simulation software
1. Temperature heated air
2. Flow of the heated air
3. Speed of the screwpump
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KOENST
Renewable energy-efficient plastics production technologies
Computer simulation model
For the simulation three situations (with increasing complexity)
were formulated:
I. A test set-up with an empty silo
II. A test set-up with granules, simulated as a packed bed
III. A test set-up with granules, simulated as fluidized bed
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KOENST
Renewable energy-efficient plastics production technologies
Results Situation I
Results practical test set-up
Results computer simulation
Situation: I
Target temperature: 47˚C
Target flow: 80 m3/h
Environmental temperature: 22˚C
Situation: I
Target temperature: 47˚C
Target flow: 80 m3/h
Environmental temperature: 22˚C
Air temperature
50
Temperature (˚C)
45
40
35
30
25
20
0
2000
4000
6000
8000
10000
12000
Time (s)
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KOENST
Renewable energy-efficient plastics production technologies
Discussion situation I
Target temperature is set at 47 ˚C → heated air is
not reaching the inner side of the silo.
Air temperature
50
Temperature (˚C)
45
40
35
30
25
20
0
2000
4000
6000
8000
10000
12000
Time (s)
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KOENST
Renewable energy-efficient plastics production technologies
Discussion situation I
The peaks shown in the graphs → thermocouple 1
will measure sometimes a flow of cold air mixed in
the hot air.
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KOENST
Renewable energy-efficient plastics production technologies
Results & Discussion
Situation II & III
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Renewable energy-efficient plastics production technologies
Most efficient heat transfer
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Renewable energy-efficient plastics production technologies
Fluidization phases
• Packed bed
• Incipient bed
• Fluidized bed
Source: R. Shankar Subramanian - Flow through Packed Beds and Fluidized Beds
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Renewable energy-efficient plastics production technologies
Minimum fluidization velocity
• The Ergun equation
∆𝑝
150𝜇 1 − 𝜀 2 𝑢0 1.75 1 − 𝜀 𝜌𝑢02
=
+
2
2
3
𝐿
𝜑𝜑 3 𝑑𝑝
𝜑 𝜀 𝑑𝑝
• Rewritten Ergun equation
𝑔𝑔𝑓 (𝜌𝑝 − 𝜌𝑓 )𝑑𝑝 3
150(1 − 𝜀)𝑅𝑅 1.75𝑅𝑅 2
𝐴𝐴 =
=
+
2
2
3
𝜑 𝜀
𝜇
𝜑𝜀 3
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KOENST
Renewable energy-efficient plastics production technologies
Pressure drop
• Pressure drop at the minimum fluidization velocity
∆𝑝
150𝜇 1 − 𝜀 2 𝑢0 1.75 1 − 𝜀 𝜌𝑢02
=
+
𝐿
𝜑𝜑 3 𝑑𝑝
𝜑 2 𝜀 3 𝑑𝑝2
• Resistance coefficients
𝐶𝑟𝑟 =
150𝜇 1−𝜀 2
2
𝜑 2 𝜀 3 𝑑𝑝
𝐶𝑟𝑟 =
1.75(1−𝜀)𝜌
𝜑𝜀 3 𝑑𝑝
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KOENST
Renewable energy-efficient plastics production technologies
Front view
Total pressure
drop
Top view
3d view
Detail view
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KOENST
Renewable energy-efficient plastics production technologies
Front view
Total velocity profile
Top view
3d view
Detail view
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Renewable energy-efficient plastics production technologies
Test results
Packed bed height
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Renewable energy-efficient plastics production technologies
Conclusion
• Theory and simulation model match
• Simulation model and real model match
• Good base for further research
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