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FEA simulation aids development of seals for use in challenging oil and gas applications
TECHNOLOGY FOCUS
FEA simulation aids development of seals for use in challenging oil and gas applications Edited by Simon Atkinson The range of benefits associated with finite element analysis (FEA) simulation makes the technique highly favourable when it comes to developing sealing technology and products for particularly demanding applications, such as those found in the oil and gas sector, as Precision Polymer Engineering Ltd briefly explains in this technology focus article. FEA is a computer-based technique that calculates how components are likely to perform in real-life applications. This advanced technique can determine how components may be impacted by exposure to extremes in temperature and pressure, particular stresses and aggressive chemical environments. Skilled use of FEA simulation can remove the need for extensive manual testing by accurate modelling through predictive behaviour. Mechanical stress and vibration are amongst the factors typically considered in this type of analysis.
Highlighting potential faults FEA simulation enables design engineers to highlight potential faults or areas of weakness in a
component, which may impact its overall efficiency or its ability to function in a given application. The range of benefits associated with FEA simulation makes the technique highly favourable when it comes to developing sealing technology and products for particularly demanding or complex applications, such as those found in the oil and gas sector.
Challenging industry The long-term reliability of sealing components is vital for any critical application. Precision Polymer Engineering (PPE) works across a diverse range of industries – offering sealing products for critical applications in, for example, the food, pharmaceutical, chemical processing and marine engine sectors. Whilst there are severe ramifications for sealing component failures across applications
in these industries, few challenges are more intense than those faced by seals used in equipment and systems in the oil and gas industry.
‘The long-term reliability of sealing components is vital for any critical application.’ These need to withstand the most intense of operating environments, with extreme temperatures, pressures and chemical aggression. FEA simulation enables component developers to foresee what may have been considered unpredictable variables, and to engineer resistances to counteract these issues before they materialise.
Long-term reliability Owing to costs involved with missed productivity, downtime is not an option for oil and gas applications. Design engineers working in these fields must opt for component manufacturers adhering to the highest standards of quality and long-term
Finite element analysis simulation (graphic courtesy of Precision Polymer Engineering Ltd).
February 2019
Sealing Technology
7
TECHNOLOGY FOCUS/RECENTLY PUBLISHED PAPERS
FEA at Precision Polymer Engineering At PPE, the virtual environment of FEA simulation enables its engineers to create accurate models by characterising PPEspecific materials under set conditions. Through this it is able to predict how sealing components will behave in real-life applications and detect where compromises in performance and/or reliability may become apparent. Alongside FEA simulation, the firm offers a comprehensive suite of sealing technologies and services to ensure that a customer’s set-up delivers optimal performance. reliability in order to deliver undisturbed operational efficiency. FEA simulation is of
Recently Published Papers • P. Pourmand, M.S. Hedenqvist and U.W. Gedde, KTH Royal Institute of Technology, School of Chemical Science and Engineering, Fibre and Polymer Technology, Stockholm, Sweden; and I. Furó, KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Stockholm, Sweden: ‘Radiochemical ageing of highly filled EPDM seals as revealed by accelerated ageing and ageing in-service for 21 years’, Polymer Degradation and Stability, Volume 144, October 2017, pages 473– 484. In this study, highly filled EPDM rubber, used in cable transit seals in nuclear power plants, was exposed to γ radiation at a high dose rate at 23°C in media with different oxygen partial pressures (1 kPa to 21.2 kPa). The motivation of this research was driven by the following: highly filled polymers are replacing halogen-containing polymers and these materials have not received sufficient attention in the literature; and there is a need to find efficient tools to make possible condition monitoring and extrapolation. Several profiling methods were used: IR microscopy, micro-indentation, micro-sample extraction/gravimetry and non-invasive NMR spectroscopy. Three different deterioration pro8
Sealing Technology
central importance to ensuring these standards are met and maintained. Oil and gas companies must also consider their environmental responsibilities in addition to their own losses, should component failure occur. Whilst plummeting productivity levels during downtime are costly to the company, should component failure cause an oil or gas leak, these costs are minor in relation to the resulting environmental fines.
Benefits of FEA
• •
•
•
performance is weak or requires modification – improving time efficiency; requires less testing and fewer modifications; improves versatility, because any modification can be tested using FEA simulation before a component is approved and manufactured; safeguards against the potential risks of component failure, enabling engineers to identify and react to them in advance – improving cost efficiency; and helps engineers gain a more thorough understanding of the general behaviour of the product, and the nature of the application as a whole.
FEA simulation is an advantageous asset for any sealing application in any industry – not just the oil and gas sector. This kind of detailed analysis: • removes the need for real-life testing and, therefore, is more efficient in terms of materials and resources; • provides an analysis accurate enough to isolate the exact area or location where
(This technology focus is based on press material issued by Precision Polymer Engineering Ltd.)
cesses were identified: polymer oxidation, migration of low molar mass species and anaerobic changes in the polymer network. IR microscopy, micro-indentation profiling and the portable NMR method confirmed diffusion-limited oxidation in samples irradiated in air. The inner non-oxidised part of the blocks showed a pronounced change in the indenter modulus by migration of primarily glyceryl tristearate (migration was accelerated by the presence of oxygen in the surface layer) and anaerobic changes in the polymer network. For extrapolation or for condition monitoring, it is best to use the data obtained by indenter modulus profiling and to use the correlation between indenter modulus and strain-at-break to quantify the sample status. Non-invasive NMR profiling provided useful data, but was less precise than the indenter modulus data in predicting the strain-at-break. • X. Liu, R. Yamaguchi, N. Umehara, M. Murashima and T. Tokoroyama, Department of Mechanical Science and Engineering, Nagoya University, Furocho, Chikusa-ku, Nagoya, Japan: ‘Effect of oil temperature and counterpart material on the wear mechanism of ta-CNx coating under base oil lubrication’, Wear, Volumes 390–391, 15 November 2017, pages 312–321. Tetrahedral amorphous carbon nitride (ta-CNx) – as an emerging and promising diamond-like carbon (DLC) – has better mechanical properties than amorphous carbon nitride (a-CNx), ensuring sufficient durability, and overcoming the limit of high internal stress of tetrahedral amorphous carbon
(ta-C). This means that further research into ta-CNx coatings for tribological and mechanical applications is certainly worthwhile. In this study, the authors look at the effects of oil temperature and counterpart material on the wear behaviour of ta-CNx coatings under baseoil lubrication, and further clarify the wear mechanism. The ta-C and ta-CNx coatings, with an N/C atomic ratio of 2.2% and 11.0%, were deposited by an ion-beam assisted filtered arc deposition (IBA-FAD) system, and the tribological tests were performed using a ball-ondisk tribo-tester, with a steel ball coated with ta-C and ta-CNx sliding against an uncoated disk under base-oil lubrication. The results show that nitrogen doping tends to decrease the hardness and Young’s modulus by reducing the sp3 structure. When sliding against a steel disk, with an increase in sliding distance, ta-CNx shows obviously distinct wear behaviour compared with ta-C – much more slowly increasing wear volume and exhibiting excellent wear resistance. Increasing the oil temperature from room temperature to 120°C results in rising wear rates for all coatings, with a totally worn out ta-C and much lower wear rate for ta-CNx, which decreases by more than half, compared with ta-C, for high nitrogen content ta-CNx. However, as the counterpart material changed from steel to alumina, the wear rate presents oppositely increasing tendency with the N/C ratio. It is found that the wear performance of ta-CNx coating has a clear dependence on the oil temperature and
For further information, visit: www.prepol.com/industries/oil-gas
February 2019
FEA simulation aids development of seals for use in challenging oil and gas applications Edited by Simon Atkinson The range of benefits associated with finite element analysis (FEA) simulation makes the technique highly favourable when it comes to developing sealing technology and products for particularly demanding applications, such as those found in the oil and gas sector, as Precision Polymer Engineering Ltd briefly explains in this technology focus article. FEA is a computer-based technique that calculates how components are likely to perform in real-life applications. This advanced technique can determine how components may be impacted by exposure to extremes in temperature and pressure, particular stresses and aggressive chemical environments. Skilled use of FEA simulation can remove the need for extensive manual testing by accurate modelling through predictive behaviour. Mechanical stress and vibration are amongst the factors typically considered in this type of analysis.
Highlighting potential faults FEA simulation enables design engineers to highlight potential faults or areas of weakness in a
component, which may impact its overall efficiency or its ability to function in a given application. The range of benefits associated with FEA simulation makes the technique highly favourable when it comes to developing sealing technology and products for particularly demanding or complex applications, such as those found in the oil and gas sector.
Challenging industry The long-term reliability of sealing components is vital for any critical application. Precision Polymer Engineering (PPE) works across a diverse range of industries – offering sealing products for critical applications in, for example, the food, pharmaceutical, chemical processing and marine engine sectors. Whilst there are severe ramifications for sealing component failures across applications
in these industries, few challenges are more intense than those faced by seals used in equipment and systems in the oil and gas industry.
‘The long-term reliability of sealing components is vital for any critical application.’ These need to withstand the most intense of operating environments, with extreme temperatures, pressures and chemical aggression. FEA simulation enables component developers to foresee what may have been considered unpredictable variables, and to engineer resistances to counteract these issues before they materialise.
Long-term reliability Owing to costs involved with missed productivity, downtime is not an option for oil and gas applications. Design engineers working in these fields must opt for component manufacturers adhering to the highest standards of quality and long-term
Finite element analysis simulation (graphic courtesy of Precision Polymer Engineering Ltd).
February 2019
Sealing Technology
7
TECHNOLOGY FOCUS/RECENTLY PUBLISHED PAPERS
FEA at Precision Polymer Engineering At PPE, the virtual environment of FEA simulation enables its engineers to create accurate models by characterising PPEspecific materials under set conditions. Through this it is able to predict how sealing components will behave in real-life applications and detect where compromises in performance and/or reliability may become apparent. Alongside FEA simulation, the firm offers a comprehensive suite of sealing technologies and services to ensure that a customer’s set-up delivers optimal performance. reliability in order to deliver undisturbed operational efficiency. FEA simulation is of
Recently Published Papers • P. Pourmand, M.S. Hedenqvist and U.W. Gedde, KTH Royal Institute of Technology, School of Chemical Science and Engineering, Fibre and Polymer Technology, Stockholm, Sweden; and I. Furó, KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Stockholm, Sweden: ‘Radiochemical ageing of highly filled EPDM seals as revealed by accelerated ageing and ageing in-service for 21 years’, Polymer Degradation and Stability, Volume 144, October 2017, pages 473– 484. In this study, highly filled EPDM rubber, used in cable transit seals in nuclear power plants, was exposed to γ radiation at a high dose rate at 23°C in media with different oxygen partial pressures (1 kPa to 21.2 kPa). The motivation of this research was driven by the following: highly filled polymers are replacing halogen-containing polymers and these materials have not received sufficient attention in the literature; and there is a need to find efficient tools to make possible condition monitoring and extrapolation. Several profiling methods were used: IR microscopy, micro-indentation, micro-sample extraction/gravimetry and non-invasive NMR spectroscopy. Three different deterioration pro8
Sealing Technology
central importance to ensuring these standards are met and maintained. Oil and gas companies must also consider their environmental responsibilities in addition to their own losses, should component failure occur. Whilst plummeting productivity levels during downtime are costly to the company, should component failure cause an oil or gas leak, these costs are minor in relation to the resulting environmental fines.
Benefits of FEA
• •
•
•
performance is weak or requires modification – improving time efficiency; requires less testing and fewer modifications; improves versatility, because any modification can be tested using FEA simulation before a component is approved and manufactured; safeguards against the potential risks of component failure, enabling engineers to identify and react to them in advance – improving cost efficiency; and helps engineers gain a more thorough understanding of the general behaviour of the product, and the nature of the application as a whole.
FEA simulation is an advantageous asset for any sealing application in any industry – not just the oil and gas sector. This kind of detailed analysis: • removes the need for real-life testing and, therefore, is more efficient in terms of materials and resources; • provides an analysis accurate enough to isolate the exact area or location where
(This technology focus is based on press material issued by Precision Polymer Engineering Ltd.)
cesses were identified: polymer oxidation, migration of low molar mass species and anaerobic changes in the polymer network. IR microscopy, micro-indentation profiling and the portable NMR method confirmed diffusion-limited oxidation in samples irradiated in air. The inner non-oxidised part of the blocks showed a pronounced change in the indenter modulus by migration of primarily glyceryl tristearate (migration was accelerated by the presence of oxygen in the surface layer) and anaerobic changes in the polymer network. For extrapolation or for condition monitoring, it is best to use the data obtained by indenter modulus profiling and to use the correlation between indenter modulus and strain-at-break to quantify the sample status. Non-invasive NMR profiling provided useful data, but was less precise than the indenter modulus data in predicting the strain-at-break. • X. Liu, R. Yamaguchi, N. Umehara, M. Murashima and T. Tokoroyama, Department of Mechanical Science and Engineering, Nagoya University, Furocho, Chikusa-ku, Nagoya, Japan: ‘Effect of oil temperature and counterpart material on the wear mechanism of ta-CNx coating under base oil lubrication’, Wear, Volumes 390–391, 15 November 2017, pages 312–321. Tetrahedral amorphous carbon nitride (ta-CNx) – as an emerging and promising diamond-like carbon (DLC) – has better mechanical properties than amorphous carbon nitride (a-CNx), ensuring sufficient durability, and overcoming the limit of high internal stress of tetrahedral amorphous carbon
(ta-C). This means that further research into ta-CNx coatings for tribological and mechanical applications is certainly worthwhile. In this study, the authors look at the effects of oil temperature and counterpart material on the wear behaviour of ta-CNx coatings under baseoil lubrication, and further clarify the wear mechanism. The ta-C and ta-CNx coatings, with an N/C atomic ratio of 2.2% and 11.0%, were deposited by an ion-beam assisted filtered arc deposition (IBA-FAD) system, and the tribological tests were performed using a ball-ondisk tribo-tester, with a steel ball coated with ta-C and ta-CNx sliding against an uncoated disk under base-oil lubrication. The results show that nitrogen doping tends to decrease the hardness and Young’s modulus by reducing the sp3 structure. When sliding against a steel disk, with an increase in sliding distance, ta-CNx shows obviously distinct wear behaviour compared with ta-C – much more slowly increasing wear volume and exhibiting excellent wear resistance. Increasing the oil temperature from room temperature to 120°C results in rising wear rates for all coatings, with a totally worn out ta-C and much lower wear rate for ta-CNx, which decreases by more than half, compared with ta-C, for high nitrogen content ta-CNx. However, as the counterpart material changed from steel to alumina, the wear rate presents oppositely increasing tendency with the N/C ratio. It is found that the wear performance of ta-CNx coating has a clear dependence on the oil temperature and
For further information, visit: www.prepol.com/industries/oil-gas
February 2019