Supercritical CO2-Extraction –
A New Method to Remove Harmful
Substances from Recovered Paper
EFPRO – CEPI 2nd Early Stage Researchers Workshop
27th November 2013, Brussels
Dipl.-Ing. Saskia Runte
Prof. Dr.-Ing. Samuel Schabel
Paper Technology and Mechanical
Process Engineering (PMV)
Technische Universität Darmstadt
Alexanderstraße 8
64283 Darmstadt, Germany
[email protected]
[email protected]
November 27th 2013 | Chair of Paper Technology and Mechanical Process Engineering | Dipl.-Ing. Saskia Runte | 1
Outline
 Introduction
• Harmful Substances
• Supercritical CO2
 Experimental Set-Up
 First Results
 Conclusion
 Outlook
November 27th 2013 | Chair of Paper Technology and Mechanical Process Engineering | Dipl.-Ing. Saskia Runte | 2
Harmful Substances to be Investigated
Resulting from…
Benzophenone
• Printing inks
Formaldehyd
• Non-carbon papers
Glyoxal
• Additives
PCP = Pentachlorophenol
• Archive papers
Bisphenol A
• ….
Phthalates
Prim. arom. amine = Primary aromatic amines
PCB = Polychlorinated biphenyls
DIPN = Diisopropylnaphthalene
PAH = Polycyclic aromatic hydrocarbons
Mineral oil-HC = Saturated aliphatic and aromatic hydrocarbons
low
Polarity
November 27th 2013 | Chair of Paper Technology and Mechanical Process Engineering | Dipl.-Ing. Saskia Runte | 3
high
Extraction with Supercritical CO2
 Supercritical CO2:
• Above its critical temperature (31 °C) and critical pressure (74 bar)
(31)
Phase diagram of carbon dioxide
Based on: http://de.wikipedia.org/wiki/Kritischer_Punkt_(Thermodynamik) [03.2013]
November
27th
2013 | Chair of Paper Technology and Mechanical Process Engineering | Dipl.-Ing. Saskia Runte | 4
Extraction with Supercritical CO2
 Supercritical CO2:
• Above its critical temperature (31 °C) and critical pressure (74 bar)
• Properties:
Gas
Supercritical CO2
Liquid
Viscosity in mPa*s
0.01
0.01 – 0.1
1
Diffusion coeff. in m²/s
10-5
10-7 – 10-8
10-9
Density in g/cm³
0.001
0.2 – 0.9
1
 Known from various industry sectors
• E. g. food technology for coffee, tobacco
or hops extraction
• Surface cleaning from various steels,
gold, silver, …
(31)
Phase diagram of carbon dioxide
November 27th 2013 | Chair of Paper Technology and Mechanical Process Engineering | Dipl.-Ing. Saskia Runte | 5
Experimental Set-Up
expansion valve
Recovered Paper
rotameter
CO2
highpressure
Dsd
extractor
Extract
extract
collector
Analysis of extracted
recovered paper
piston pump
precooling
HP-Extraction
CO2
November 27th 2013 | Chair of Paper Technology and Mechanical Process Engineering | Dipl.-Ing. Saskia Runte | 6
Removal of Harmful Substances from
Recovered Paper
Target:
•
Influence of CO2 mass flow by variation of extraction time (10, 20,
40, 60 min) and influence of sampling height (top, middle, bottom)
Used material:
•
280 g b. d. newspaper
Process parameters (Pilot plant TU Hamburg-Harburg):
• Pressure: 300 bar
• Temperature: 40 °C
Analysed substances:
• Benzophenone
• Diisopropylnaphthalene (DIPN)
• Mineral oil
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Benzophenone
10 min
20 min
40 min
measuring inaccuracy: 0.2 – 0.3 mg/kg
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60 min
Diisopropylnaphthalene (DIPN)
10 min
20 min
40 min
measuring inaccuracy: ~ 0.5 mg/kg
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60 min
Mineral oil
10 min
20 min
40 min
60 min
measuring inaccuracy: up to 30 %
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Conclusion
 Different extraction behaviour of different harmful substances
• No significant removement of benzophenone content
• Removement of DIPN content up to 60 %
• Removement of mineral oil content up to 95 %
 No significant changes in extraction for different sampling heights
 Tendencial higher removement of harmful substances with
increasing CO2 mass flow
 Promising project to remove harmful
substances from recovered paper
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Outlook
 Detailed view on influencing parameters (temperature, pressure, …)
 Investigation of different paper and board products (magazines,
corrugated board, …)
 Detection of potential synergies (deinking behaviour, strength
properties, …)
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Thank you for your attention.
For further information contact:
Paper Technology and Mechanical Process Engineering (PMV)
Technische Universität Darmstadt
Alexanderstraße 8
64283 Darmstadt, Germany
Dipl.-Ing. Saskia Runte
[email protected]
November 27th 2013 | Chair of Paper Technology and Mechanical Process Engineering | Dipl.-Ing. Saskia Runte | 13