Over the last quarter, the branch has held three technical meetings. On Thursday 22nd September, there was the annual joint meeting with TWI, and Neil Gallon, Principal Engineer of Rosen, gave a talk on ‘Repurposing of Pipelines in the Energy Transition’.
There are many integrity challenges and differences between hydrogen, CO2 and hydrocarbon pipelines, and a pragmatic phased approach is required to enable safe and economic conversion of existing infrastructure.
Hydrogen is the lightest and most abundant element, and has the highest energy content of any common fuel by weight. It is found in water or hydrocarbons and can be produced without carbon footprint through electrolysis, steam methane reforming (SMR) and Carbon Capture (CC). It can be transported over long distances, stored like traditional fuels, but produces clean power and heat so it has advantages over fossil fuels in the drive towards net zero emissions.
The European hydrogen backbone will continue to grow with more connections across member states to about 26,000km by 2035 with a plan to double again by 2040, this will be approximately 69% of retrofitted infrastructure and 31% of new hydrogen pipelines. This emphasis on the re-use of existing infrastructure, while obviously attractive, places heavy demands on inspection and integrity engineering in order to ensure that assets remain fit for purpose.
In the transportation of hydrogen and “rich” CO2 by pipelines, there are key integrity challenges to be addressed for long-term safe operations. However, the major points of interest are the same as any pipeline integrity management system:
• Pipeline condition – What are the time-dependent threats? Which type of defects should I tackle? Where are they located? How severe are they?
• Integrity Remaining Life – How safe is my pipeline operations? How long can l operate it?
• Consequences – What are the consequences of loss of containment?
• Management – Can I safely manage pipeline operations going forwards?
Nonetheless, there are differences between the different modes of transportation which derive from the specific physicochemical behaviour of the fluid, and its interaction with the pipeline materials. For instance, internal corrosion is not a major concern for hydrogen service, while it is a key consideration for CO2 (and hydrocarbon) infrastructures. On the other end of the spectrum, ‘crack management’, broadly speaking, is a more critical topic for hydrogen pipelines than for other services.
While CO2 and hydrogen pipelines could be purpose-built to address the range of applicable integrity concerns, it is very likely that a major proportion of the future transmission network will revolve around the integration of existing Natural Gas (NG) or other hydrocarbon infrastructures. Hydrogen and CO2 pipeline design codes tend to be more constraining or restrictive than that for hydrocarbons. For example, typical hydrogen standards will limit the use of steels up to API 5L X52 (L360) to tackle hydrogen embrittlement issues, while over 45% of the European NG system is designed with higher steel grades.
The fundamental feature, which drives much of the integrity concerns and challenges in gaseous hydrogen pipelines, is the absorption of atomic hydrogen within the steel microstructure. The interactions of hydrogen lead to major degradation of mechanical properties, such as strength, ductility, fracture toughness and fatigue crack growth rate, and have been studied by various researchers of material types used in repurposed pipelines such as, API Series 5L X42, X52, X65, X80 and X100.The data are not yet fully comprehensive but all show that all properties are reduced by increasing levels of hydrogen.
A key reason for this is that the magnitude of interaction of hydrogen and steel is determined by the specific nature of the steel microstructures and chemistries not just the grade. This important facet puts a greater emphasis on the understanding of materials ‘DNA’ and on testing. These aspects are at the core of conversion and integrity management strategies. Crack detection technologies such as Electro-Magnetic Acoustic Transducer (EMAT) and materials properties in-line inspection (ILI), such as ROSEN’s RoMat PGS and DMG services, are likely to be integral to the inspection and conversion of hydrogen pipelines.
In many respects, the management of time-dependent threats in CO2 pipelines is an extension of the knowledge and the experience gained through the traditional oil and gas industry. The main key difference is that in “traditional” gas production, CO2 is mainly an unwanted by-product or impurity, while for CCUS, CO2 will be the primary fluid being transported, and hence will likely be at a higher partial pressure (i.e. presents a greater corrosion risk) and may have its own inherent impurities. Nonetheless, internal time-dependent threats will remain negligible, so as long as no free (separated) liquid water is present in the pipeline. This means that inspection of a CO2 line with ultrasonic technologies, which generally rely on a water couple, can be challenging and other methods must be considered.
Neil summarised by saying, the conversion of existing infrastructure to hydrogen or CO2 service brings unique integrity management challenges. It is unreasonable to expect that facilities designed specifically for hydrocarbon service can be directly converted to hydrogen or CO2 service without due diligence being applied. Management strategies will revolve around understanding material “DNA” and testing, and the deployment of in-line inspections to address pipeline and pipework fitness-for-service.
For hydrogen lines some of the major time dependent integrity threats are associated with potential hydrogen embrittlement of the pipeline steel, and the consequent threat of cracking. ILI of hydrogen pipelines can also be challenging due to the different physical and flow characteristics of hydrogen compared to natural gas, despite this it can be achieved.
For CO2 lines, ILI is necessary to understand the materials and presence of any time dependent threats such as metal loss corrosion or cracking. ILI of dense phase CO2 pipelines is challenging due to the nature of the fluid being transported.
On Tuesday 25th October, the branch welcomed Vinay Tripurana, Applications Engineering, Manager, Flexitallic UK Ltd., to talk on “Flange Face Corrosion in seawater and hydrocarbon environments, related to gasket material selection”.
Vinay oversees the company’s UK Applications Engineering Team. He is a Chartered Mechanical Engineer with Masters’ degree in Manufacturing Systems and has several years’ experience in providing engineered solutions to a wide range of industries including automotive, fabrication and sealing technology.
Bolted flange joints in seawater and hydrocarbon services can be vulnerable to gasket degradation and flange face corrosion. In its guidance document on corrosion management, the UK’s Energy Institute ranks corrosion as the second most frequent cause in initiating loss of hydrocarbon containment in offshore platforms, and highlights corrosion as a major threat to asset integrity and plant efficiency. Flange face corrosion can be extremely difficult to detect prior to leakage leading to considerable loss of valuable resources. The impact on the environment can also be a major concern, as can the immediate safety of plant personnel. Replacement or remedial works often means unscheduled downtime, additional costs, and reduced asset efficiency.
A holistic approach must be taken to a flanged assembly as there are several aspects which are critical to good integrity, and the gasket alone cannot solve all issues. Junctions differ in that there are process parameters of pressure, temperature and carried media, and the hardware differs in design of bolting, support, insulation, and types of flanges. Finally, the installation must be well supervised by competent personnel and correct lubricants and tools used in a controlled and safe manner to give good integrity of a pipe junction.
Unfortunately, gaskets that brought us through the ‘oil boom’ years were traditionally made of asbestos which was a fire-proof material, could deal with most chemicals, and had excellent sealing and corrosion prevention properties, but the material fell from use due to health and safety issues. Traditional alternative materials such as Graphite, Mica and PTFE have characteristics that can be, or appear to be, very useful to flange applications, but they do not have the qualities to offer optimum performance in the area of corrosion prevention. Graphite is naturally an electrical conductor and its ‘noble’ nature promotes corrosion, Mica exhibits very poor sealing characteristics and PTFE is not fire safe and exhibits poor sealing characteristics. This has led to further research into alternative materials to mitigate this issue. For example, Flexitallic went in search of a new material that would:
– Mitigate flange face corrosion – electrically neutral and clean
– Significantly improve connection tightness (Net Zero)
– Be fully compliant with current gasket standards – ASME B16.20
– Meet industry service envelope requirements (-196 to 260oC & B16.5 #150 thru #2500)
– Meet fire safe requirements
– Be easy to use and require no change to established installation procedures
– Economically viable compared with graphite
The solution was a new composite material now known as Corriculite – a spiral wound gasket material based on vermiculite with filler materials and enhancements. It is electrically inert, high purity spiral wound with good tightness properties, that is both fire safe and compliant with the requirements of ASME B16.20. It offers a direct and cost-effective, replacement for conventional, graphite filled gaskets. (Editor: more information can be found in the May/June issue of the magazine).
Once the fundamental gasket property criteria had been fulfilled, the material was tested to validate it for flange face corrosion and in order to prove this, corrosion testing was conducted to ISO 9227, which is simple 600 hour salt spray test (90 mins spray, then 90 mins dry with 170 cycles in total) for M20 Stainless steel bolts, with material to be tested sandwiched between SS washers with PTFE isolator. Multiple rings were placed in series and bolts torqued to 20 MPa.
Other required testing involved flange face corrosion sensitivity testing. Potentiostatic polarisation techniques were used with an impressed current to accelerate the likely corrosion reactions, comparing older graphite performance with the new material. The voltage required to initiate corrosion in graphite was found to be nearly half as much as for the new Corriculite material. Seal tightness was also assessed using a cyclic pressure test to EN13555, whereby 4” diameter sample gaskets were loaded and unloaded to increasing levels of pressure up to 40 bar of helium, and the leakage measured. Quick comparison showed that there is superior performance at the 3 main stress ranges tested when compared with graphite.
A validation test for thermal cycling was also conducted to demonstrate the gasket’s ability to seal when exposed to thermal fluctuations. For the ‘ambient’ test, the gasket was pressurised to 51 bar for 1 hour, a ‘fail’ being drop > 1 bar. A further high temperature test was conducted at 42.5bar pressure at 260°C for 1 hour then cooled for, for 10 cycles in total. These independent results showed max 4 bar loss over the thermal cycling.
Cryogenic testing was also conducted, which is a’ Blowdown’ qualification for between -110C and -196C. Again, this was a pressurised, hold 1 hour, depressurise, but for 3 cycles on ASME Class 150 & 900 grp2.2 flanges. The leakage test showed tight seal and high performance. Fire safety tests were also passed for the new material at 650C 30min cyclic test with forced cool and pressurised cycles.
Vinay then concluded his talk by stating, the Corriculite gasket development is proving to be an innovative spiral wound filler material that mitigates flange face corrosion in up-stream environments. It is fully compliant with current gasket standards and meets industry service envelope requirements fire safe complaint. It can be used as a direct replacement for graphite using existing assembly procedures and is seen as a viable economic alternative to conventional graphite sealing technology.
For its final technical meeting, the branch held a joint event with The Mining Institute of Scotland (an Affiliated Local Society of IOM3) on Wednesday 16th November, with Dr Prafull Sharma as the speaker. Prafull currently serves as the Chief Technology Officer of UK based CorrosionRADAR Ltd which is bringing innovative corrosion monitoring technologies to the Energy Sector using Industrial Internet of Things (IIoT). As a Technologist, he has brought vast industrial experience to Corrosion Management, especially in the area of digitalisation of on which there are several inventions to his credit.
Predictive maintenance and Industry seems to have been talked about for at least a decade now, but in his talk, Prafull considered what this means on a ‘day-to-day’ basis to asset integrity professionals. New advancements in technologies including sensors, battery powered devices, wireless connectivity, remote data analytics are enabling creation of Industrial Internet of Things (IIoT).
Corrosion Management is now emerging as a big user for applications of digitalisation tools. CorrosionRADAR invented a predictive CUI monitoring system that combines corrosion and moisture sensors, which is gaining increasing global traction, addressing a major issue for the industry.
CorrosionRADAR currently have a number of site trials ongoing with both UK and overseas Energy Operators. They continue to have many have many high-profile Investors including – Net Zero Technology Centre (NZTC), and Saudi Aramco Energy Ventures (SAEV).
Certificates of Appreciation were issued to all our branch presenters. The branch also held its AGM at the October meeting, during which a new committee was elected.
Abstracts of potential papers for the Aberdeen Technical Programme are always welcome, and anyone wishing to join committee should correspond with the Aberdeen Chair: Dr Muhammad Ejaz itsejaz@yahoo.com
Further Information about the Aberdeen Branch, and past presentations, may be found on their website page: Aberdeen Branch – Institute of Corrosion (icorr.org), and to join the Aberdeen Branch mailing list, please contact: icorrabz@gmail.com
TABLE:
Dr Muhammad Ejaz Chair Hooman Takhtechian YEP 2022 Coordinator and Past Chair
Adesiji Anjorin Vice-Chair Leela Ramachandran University Liaison & CPD Officer
Dr Nigel Owen Secretary External Steve Paterson YEP Mentors and Case Study Co-ordinator
Lian Ling Beh Secretary Internal Dr Olubayo Latinwo Branch Sponsorship Officer
Bryn Roberts Financial Officer Dr Yunnan Gao Website Officer and Past Chair
Mei Ling Cheah Event Co-ordinator and Young ICorr Officer Stephen Tate Observer and Past Chair
Aberdeen Branch Positions for 2022-2023 Session.
Planned expansion of hydrogen pipeline network in Europe.
Influence of hydrogen on ‘Fitness for Service’ assessment.
Influence of hydrogen on ‘Fitness for Service’ assessment.
New sealing material – materials selection and the galvanic series.
New sealing material – induced corrosion evaluation.
Fire safe testing for flanged assemblies.
Process of CUI and impact on industry.
Example of installation to vessel with cyclic temperature operation.
New Aberdeen Committee 2022-2023 with retiring Branch Members (circled) – Dr Olubayo Latinwo
(last Vice Chair) and Hooman Takhtechian (last Chair).
