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- 3 Gefahrgutumschließungen; Energiespeicher (27)
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- 2 Prozess- und Anlagensicherheit (3)
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- 8 Zerstörungsfreie Prüfung (3)
- 8.1 Sensorik, mess- und prüftechnische Verfahren (3)
Eingeladener Vortrag
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Schuld an Korrosion
(2003)
Das Gefährdungspotential von Rohrleitungen hängt primär von den Eigenschaften des durchfließenden Stoffes, den Betriebsbedingungen und den äußeren Beanspruchungen ab. Zu den Hauptschadensursachen an Rohrleitungen zählen Korrosion, Druckstöße und Kavitationsschläge, Zeitstandbeanspruchung, struktur- und fluidmechanische Schwingungen, Fremdberührungen, elektrische Fremdbeeinflussung und geologische Besonderheiten im Bereich des Rohrleitungsverlaufes.
Biofuels including ethanol and biodiesel (FAME) represent a renewable fuel alternative to petroleum-derived transport fuels. The aim of this work was to study the interaction between high density polyethylene (HDPE) with permeation barriers in form of polyamide (PA) and fluorination, and biofuels such as E85 (fuel with 85 % ethanol), biodiesel and B10 (heating oil with 10 % biodiesel). 10 l jerrycans made of polyethylene with permeation barrier of PA were filled with E85 and biodiesel and exposed to temperatures of 20 °C and 40 °C for 5 years. Half of the 20 l jerrycans of HDPE for filling with B10 were fluorinated at the inner layer to prevent permeation before the exposure. Tensile properties were determined once a year, and FTIR-spectroscopy was used to evaluate possible changes.
The tensile properties tensile strength and breaking elongation of HDPE jerrycan cuttings with permeation barrier decreased, but not significantly, after immersion in E85, biodiesel and B10. The elasticity modulus of the polyethylene grades was especially reduced during exposure to E85.
The FTIR spectra of HDPE jerrycan cuttings with permeation barrier showed that immersion tests for five years with the test fuels at 20 °C and 40 °C did not lead to a decomposition of the permeation barriers.
Biofuels including ethanol and biodiesel (FAME) represent a renewable fuel alternative to petroleum-derived transport fuels. The aim of this work was to study the interaction between high density polyethylene (HDPE) with permeation barriers in form of polyamide (PA) and fluorination, and biofuels such as E85 (fuel with 85 % ethanol), biodiesel and B10 (heating oil with 10 % biodiesel). 10 l jerrycans made of polyethylene with permeation barrier of PA were filled with E85 and biodiesel and exposed to temperatures of 20 °C and 40 °C for 5 years. Half of the 20 l jerrycans of HDPE for filling with B10 were fluorinated at the inner layer to prevent permeation before the exposure. Tensile properties were determined once a year, and FTIR-spectroscopy was used to evaluate possible changes.
The tensile properties tensile strength and breaking elongation of HDPE jerrycan cuttings with permeation barrier decreased, but not significantly, after immersion in E85, biodiesel and B10. The elasticity modulus of the polyethylene grades was especially reduced during exposure to E85.
The FTIR spectra of HDPE jerrycan cuttings with permeation barrier showed that immersion tests for five years with the test fuels at 20 °C and 40 °C did not lead to a decomposition of the permeation barriers.
Transportation of dangerous goods are worldwide regulated in the rules or standards e.g. in the recommendations on the Transport of Dangerous Goods of the United Nations, in the Accord Européen Relatif au Transport International des Marchandises Dangereuses par Route (ADR) etc. Addi-tional to these international regulations also national regulations and stan-dards e.g. Gefahrgutverordnung Straße und Eisenbahn (GGVSE) in Ger-many are bases for the transport of hazardous materials. For the material properties of tanks in the BAM-List Requirements for Tanks for the Transport of Dangerous Goods specifications for the sub-stance prototype approval for tank materials are listed. Further compati-bility evaluations of selected metallic material groups as well as of poly-meric gasket and lining materials under the influence of dangerous goods are published in the List. There are a large number of highly corrosive dangerous goods listed, in which conventional steels are not resistant. Chemical companies, transportation providers and tank producers need tanks made of corrosion-resistant materials (corrosion retardant materi-als) in order to protect the tank shell. The application of high-alloyed stainless steels and nickel alloys as there are alloy 926 (1.4529; X1NiCrMoCuN25-20-7), alloy 31 (1.4562;X1NiCrMoCu31-27-7) and Nickel-Chromium-Molybdenum Alloy 59 (2.4605; NiCr23Mo16Al) is an al-ternative solution compared with the lining of the tanks with a polymeric material. Due to the limited number of corrosion test results with welded test sam-ples of these high-alloyed materials under the influence of corrosive dan-gerous goods BAM, Institute for Corrosion Protection (IKS) Dresden and ThyssenKrupp VDM have been performing a comprehensive test program since 2002. The program comprised corrosion resistance evaluations of the three high-alloyed materials exposed to substances representing cor-rosive dangerous goods such as inorganic halogenides, organic acidic halogenides, sulfonic acids and nitrating acids.
Pitting Prävention
(2001)
Oxidative damage of an Intermediate Bulk Container (IBC) made of polyethylene by 53 % nitric acid
(2013)
The monitoring of oil and gas pipelines by means of distributed fibre optic sensors is becoming common. The most recent development in the field of fibre optic sensing is the distributed acoustic sensing (DAS), which allows to detect and to localize third party threats to pipelines. For this purpose, fibre optic telecommunication cables located close to the pipelines are usually used. However, DAS carries a far greater potential for continuous condition monitoring of pipelines.
The interdisciplinary research project AGIFAMOR (Ageing Infrastructures – Fibre Optic Monitoring of Pipes) at BAM investigates a new technical approach to extend the application field of DAS towards the detection and localization of acoustic signals that indicate critical alterations and certain damage scenarios originated from within the pipeline or the pipe wall. Therefore, the optical fibre sensors are applied onto the pipe itself and the application procedure towards an optimal acoustic signal transduction is optimized.
A number of laboratory scale experiments were performed focusing on the signal transmission of acoustic signals as well as the detection of damages in the pipe wall by means of DAS. Furthermore, real-scale tests on a pipeline DN100 of 38m length have been carried out at the BAM test site for technical safety (BAM-TTS) to study the detection and localization of leaks and of changing flow profiles due to corrosion or sedimentation processes.
Die im In- und Ausland vorliegenden Forschungsarbeiten zur Kostenabschätzung der immissionsbedingten Materialschäden beruhen auf zwei ökonomischen Bewertungsverfahren. Bewertungsgrundlage des einen Verfahrens sind die in Labor- und Freibewitterungsversuchen ermittelten physikalisch-chemischen Dosis-Wirkungs-Beziehungen zwischen dem Schadstoffgehalt der Luft und den schadensanfälligen Materialien. Die andere Methode geht von den Unterschieden im Instandsetzungverhalten in Abhängigkeit vom Standort (Industrie-, Stadt- und Landatmosphäre) der Sachgüter aus.
Daten über Schadensursachen und die tatsächliche Nutzungsdauer der Tanks zum Transport von Gefahrgütern liegen nur in begrenztem Maße vor. Auf der Basis der Daten von Tankbaufirmen, Speditionen und Eisenbahnkesselwagen-Vermietgesellschaften wurde die durchschnittliche Lebensdauer von Tankcontainern, Tankfahrzeugen und Kesselwagen zur Beförderung von Gefahrgütern in der Praxis ermittelt und die Hauptschadensursachen analysiert. Korrosion, Risse an Schweißnähten, Gestaltungs- und Dimensionierungsfehler sowie fertigungs- und betriebsbedingte Fehler zählen zu den Hauptschadensursachen. Viele Tanks werden vor Ablauf ihrer Nutzungsdauer nicht mehr für den Transport von Gefahrgütern eingesetzt, da sie nicht mehr den geänderten gesetzlichen Anforderungen in den Gefahrgutvorschriften entsprechen. Die Voraussagen durch Literaturangaben und Ergebnisse von Korrosionsversuchen in der BAM-Liste – Anforderungen an Tanks zur Beförderung gefährlicher Güter – spiegeln sich in der Nutzungsdauer/Lebensdauer der Tanks wider.
Heizöllagerbehälter aus Polyethylenformstoffen werden seit Beginn der 70-iger Jahre in Deutschland hergestellt. Die Hersteller empfehlen zur Gewährleistung der Sicherheit nach Ablauf von 30 Jahren den Ersatz dieser Behälter. Polyethylenformstoffe unterliegen im Laufe ihrer Nutzungsdauer der Alterung durch die Veränderung ihrer Eigenschaften. Das Ausmaß der Alterung und die Art des Abbauvorganges hängen im Wesentlichen vom chemischen Abbau des Polyethylens, der Wanddicke des Behälters und den Umgebungsbedingungen ab. Bisher lagen keine Untersuchungen zum Langzeitverhalten der Polyethylenformstoffe vor, insbesondere nach einer Nutzungsdauer der Tanks über 30 Jahre. Ziel der Untersu-chungen war, den tatsächlichen Schädigungsgrad der Polyethylenformstoffe im Vergleich zu den unbelasteten Formstoffen zu ermitteln. Da die BAM bis Mitte der 90-iger Jahre für die Prüfungen und Gutachten zur Zulassung dieser Behälter zuständig war, sind die Werkstoffdaten noch vorhanden.
Als Untersuchungsmethoden wurden die Bestimmung der Schmelze-Masse-Fließrate (MFR) und die Fourier-Transformation-IR-Spektroskopie (FTIR) von Tankausschnitten aus dem Bereich des Bodens, des Mantels und des Daches von 10 ausgesonderten Behältern aus den Polyethylenformstoffen A und B herangezogen. Die Messungen der MFR der Tankaus-schnitte aus diesen Bereichen zeigten Unterschiede in den Werten in Abhängigkeit vom Ge-wicht (5 kg oder 21,6 kg), welches eingesetzt wurde. Eine Abnahme der MFR-Werte wurde für die größere Anzahl der Tankwandungsausschnitte aus dem Formstoff B nach einer Lebensdauer der Tanks > 30 Jahre gemessen. Dieser Formstoff wurde hauptsächlich durch innere Alterung infolge Vernetzungen, Verzweigungen und Weichmacherverlust und weniger durch oxidativen Abbau geschädigt. Die FTIR-Messungen der Proben aus dem Bereich des Bodens und des Mantels der Tanks zeigten, dass die Intensität der asymmetrischen/symmetrischen CH2 -Streckschwingungen im Bereich: 2800 - 2900 cm-1 und der CH2 -Biegeverformungsschwingung bei 1400 cm-1 aufgrund von Kettenspaltungen zugenommen haben. Die Intensität der Carbonylstreckschwingung C=O bei 1740 cm-1 ist niedrig. Sie ist ein Maß für die Oxidation des Polymerwerkstoffes.
Plastic storage tanks for heating oil have been on the market since the early 1970s in Germany, mainly made from polyethylene grades. Tank manufacturers and experts examining the tanks recommend the replacement of the tanks to ensure the safety after a period of 30 years. The tank manufacturer is legally obliged to specify the service life of the tanks.
Polyethylene is subject to ageing by alteration of the properties during its life cycle. A distinction is made between internal and external ageing processes. The internal ageing, such as the breakdown of internal stresses, post-crystallization, phase sepa-ration of multicomponent systems and plasticizer migration is attributed to thermodynamically instable conditions of the plastic material. The external ageing in form of stress cracking, fatigue cracking, thermooxidative degradation or swelling is based on physical or chemical effects of the environment of the polyethylene grade. The degree of ageing and the nature of the degradation process mainly depend on the chemical degradation of the polyethylene, the wall thickness of the tank and the environmental conditions. There are no results available on the long-term behaviour of the polyethylene grades used as materials for heating oil storage tanks, especially after a service life of more than 25 years.
The aim of this investigation was the determination of the factual degree of damage in comparison to the uncontaminated polyethylene grades. Data on the melt flow rate (MFR) and density of the used polyethylene grades are available because the BAM was the competent authority for the approval of the plastic heating oil storage tanks until the end of the 1980s.
The technical service of specialist companies for fuel tank disposal supplied tank sections from the bottom, the shell and the roof of 8 segregated heating oil storage tanks. Some of the tanks had been in service for more than 30 years. Two polyethylene grades mainly were used as materials for these tanks over this time. The determination of the MFR according to EN ISO 1133 and the FTIR spectroscopy followed standard test methods.
The highest average percentage increase in the MFR was determined as 31- 43 % for the bottom section of the tanks, for both the inner shell and the outer shell. The lowest increase in MFR was measured for the top of the tank, with 6 - 12 % for the inner shell and 0 - 8 % for the outer shell. The tank shell sections had an average percentage increase in MFR of 10 - 33 % for the inner shell and of 14 - 40 % for the outer shell.
The oxidative damage of the polyethylene grades was highest in the bottom area due to the permanent contact with the heating oil and degradation products.
The microtome cuttings were analyzed with image-guided infrared microscopy in the transmission mode and confirmed the results obtained with the MFR measurements.
In summary it can be concluded that the oxidative damage of the polyethylene grades after long-term contact with heating oil is relative low.
Tanks for heating oil made of polyethylene grades have been on the market since the early 1970s in Germany. Tank manufacturers recommend the replacement of the tanks after a period of 30 years due to guarantee safety. Polyethylene grades are subject to ageing by alteration of the properties during their life cycle. The degree of ageing and the nature of the degradation process mainly depend on the chemical degradation of the polyethylene, the wall thickness of the tank and the environmental conditions. There are no results available on the long-term behavior of the polyethylene grades, especially after a service life of more than 30 years. The aim of this investigation was the determination of the factual degree of damage in comparison to the uncontaminated polyethylene grades. Material data of the used polyethylene grades are available because the BAM was the competent authority for the tests and expert reports for the approval of these tanks until the middle of the 1990s.
The determination of the Melt Flow Rate (MFR) and the Fourier Transmission IR Spectroscopy (FTIR) of tank sections from the bottom, the shell and the roof of 10 segregated heating oil storage tanks produced of polyethylene grades A and B were used as tests methods.
The MFR measurements of the tank sections showed differences in the values depending on the weight which was used (5 kg or 21.6 kg). A reduction of the MFR values was measured for most of the sections of tanks made of polyethylene grade B after a service life of the tanks of more than 30 years. This grade is mainly subject to the internal ageing by cross-linkages, increased degree of branched molecules and loss of the plasticizer, and to a lesser extent by oxidative degradation. The FTIR analysis, especially of tank sections of the bottom and the shell showed that the intensity of the CH2 asymmetric and symmetric stretching vibrations in the range: 2800 - 2900 cm-1 and the CH2 bending deformation vibration at 1400 cm-1 increased due chain scissions. The intensity of the carbonyl stretching vibration C=O at 1740 cm-1 is low. The carbonyl index characterizes the degree of oxidation.