Valves are an essential part of a functioning NTS and are installed throughout the system to enable effective isolation of sections of the network, limit gas loss in an emergency, manage flow direction, facilitate maintenance, repair, modification, testing and commissioning to enable safe and effective start-up and shutdown.
Valves on our network vary in Original Equipment Manufacturer (OEM), age and size and although some are to be incorporated into our FutureGrid facility for testing, three-piece bodied isolation valves are unable to be tested for hydrogen service.
This project will understand the impact of hydrogen on three-piece bodied valves performance and materials, while also considering the repurposing vs refurbishment CBA when compared to replacing all valves with new for hydrogen service.
Benefits
Define NTS safety case for hydrogen and understanding of potential replacement
vs refurbishment cost savings associated with NTS three-piece bolted ball isolation valves.
Learnings
Outcomes
Key findings of the project:
• Criticality of historical valve information e.g. materials of construction to inform the safety case for re-use
• Methodology for repurposing of existing valves
• Methodology for reviewing the existing valve data prior to selection for repurposing
• Requirements for testing / specification of new valves
• Analysis of the impacts of API 6D Annex M to current NGT specification
• Cost benefit Analysis of repurpose versus replacement
• Environmental impact of repurposing compared to replacement
• Identification of seal grades for use for Hydrogen service
• Performance of seals in hydrogen was assessed
• Hydrogen compatibility with existing seal grades
Value tracking
Maturity
TRL4-5
This project investigated 3-Piece Robert Cort Ball 36” valves performance and materials compatibility for hydrogen use, while also considering the repurposing vs refurbishment CBA when compared to replacing the valves of this type with new for hydrogen service.
Opportunity
100% of single asset class
The project can be applied to all three-piece bodied isolation valves units primarily those manufactured by Robert Cort but learnings could also be extended to cover other OEMs
Deployment costs
Costs are detailed in the CBA of repurposing vs new. More work will be needed to up-scale the learnings and estimate the deployment cost.
Innovation cost
£ 765,462
The cost includes desktop-based work and site visits.
Financial Saving
Costs are detailed in the CBA of repurposing vs new. More work will be needed to up-scale the learnings and estimate cost and time savings.
Safety
Understanding has been developed on the impact of hydrogen on valve performance and impact on internal materials e.g. sealants for the repurposing which will feed into building the NTS safety case evidence to HSE.
Environment
Carbon footprint assessment was provided on repurposing of a valve vs. procurement of new (consider steel production, machining, and transport) has been performed.
Compliance
Support compliance
Skills & Competencies
Individuals
The project will inform individuals who are directly involved.
Future proof
Supports business strategy
The project will help enable hydrogen in the NTS and support the energy transition.
Lessons Learnt
Consideration should be made to take the learning of this project and apply them to pilot line in order to assess the effectiveness of the findings at a limited scale. Additionally further work should be committed to address practical impacts of hydrogen for example investigating the effectiveness of leakage detection and mitigation strategies. Additional work should also be undertaken to look at the performance of valve closures over time / number of operations while in hydrogen service to assess impact to current maintenance strategies.
