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Projects: Projects for Investigator
Reference Number	NIA2_SGN0028
Title	Hypurge Safe Tooling
Status	Completed
Energy Categories	Hydrogen and Fuel Cells(Hydrogen, Other infrastructure and systems R&D) 100%;
Research Types	Applied Research and Development 100%
Science and Technology Fields	ENGINEERING AND TECHNOLOGY (Mechanical, Aeronautical and Manufacturing Engineering) 100%
UKERC Cross Cutting Characterisation	Not Cross-cutting 100%
Principal Investigator	Project Contact No email address given SGN - Scotland
Award Type	Network Innovation Allowance
Funding Source	Ofgem
Start Date	01 September 2022
End Date	28 February 2023
Duration	ENA months
Total Grant Value	£62,260
Industrial Sectors	Energy
Region	Scotland
Programme	Network Innovation Allowance
Investigators	Principal Investigator	Project Contact , SGN - Scotland (99.999%)
	Other Investigator	Project Contact , SGN - Scotland (99.999%) Project Contact , SGN - Southern England (0.001%)
	Industrial Collaborator	Project Contact , SGN (0.000%)
Web Site	https://smarter.energynetworks.org/projects/NIA2_SGN0028
Objectives	The outline of work to be carried out includes:Investigation of flame arrestor development, (IGE/SR/22 requires flame arrestors to be used on vents that flow less than 10 m/s.) Investigations should be made to see if these need sourcing for hydrogen and if so, identifying where and how this can be done.Calculation of purge tables and purge calculators for hydrogen use as specified in ML2 and other SGN procedures.A purge vent design that is clearly different to a natural gas vent that can be used for hydrogen. The vent is not expected to include a flame arrestor but instead produce a flow speed sufficient to prevent burn back during a purge.Mitigating unwanted ignition mechanisms including non-sparking hand tools – review non-sparking tools used in the offshore environment and provide recommendations for H100. WP1: Project management, and communicationsThe first work pack is the project management, regular updates and project reporting to wrap up the various work packs delivering the individual tool elements.The individual work packs have individual reporting requirements, it is expected that the individual reports would be collated together in the form of a concise final report. It is not expected that this will be a detailed theoretical report, but a collection of evidence to support the design of the various tools.WP2: Flame arrestors (for use on bleed vents)The purge standard IGE/SR/22 requires flame arrestors to be used on vents that flow less than 10 m/s. The picture to the left shows four end of line flame arrestors being used on bleed pipes during a dead insertion of new PE pipe into a cast iron main. The requirement for flame arrestors needs verifying for hydrogen.A market survey is then required to identify where flame arrestors for hydrogen could be sourced. Flame arrestors are available for use with hydrogen in certain process industries. We will explore the transfer or development of this tooling for use in the Gas industry. Proposed scope of workReview standards to understand the requirement of flame arrestors, discussions with SGN and third parties to confirm field uses and requirements of flame arrestors.Carry out a market survey on flame arrestors used in the gas industry and flame arrestors used for hydrogen (including in-line and end of line arrestors) for the process industry. The survey could also include liquid seal arrestors.Identify gaps between requirements and products availableIdentify supplier/s willing to develop hydrogen flame arrestorsScope up for stage 2 if development is requiredShort report of findings and recommendationsThe standard review and market survey may extend to examining the requirement for bleed vents. Options may include producing a bleed design that will mitigate ignition of the vent without the need for a flame arrestor.WP3: Calculation of purge tablesWork from the HyPurge project has shown that gas exchange between air and hydrogen is as efficient as that between air and methane in like for like conditions. The speed up effect in hydrogen tends to improve purges for hydrogen over methane in the field. Gravitational effects due to the very low density of hydrogen hasnt caused any more challenges to the purge process than with methane, even at slow speeds. The purge calculator spreadsheet used by SGN refers to section 28.3.2 of SGN-PM-MSL/1 Management Procedure for Distribution Main-laying and Service-laying Activities as a reference document for the tables (named C11, C12 and C13 in the calculator). These tables are the basis of minimum rider and vent sizes for use with methane systems.The tables dictate the rider and vent sizes to be used to guarantee flow rates. It is likely, however that if the same tables and equipment is used for hydrogen then the flow rates will be significantly different once hydrogen dominates the system. Flow rates in hydrogen are likely to be x2.8 those for methane which will result in much faster flows during purging and other vent operations. It would be prudent to re-calculate relevant tables for use with hydrogen.The tables themselves refer back to Table 2 of IGE/SR/22 and are also linked to Table 12 of the utilisation standard IGE/UP/1. A full re-write of the standards for hydrogen would involve testing large diameters which although needed at some point is not required for H100 Fife. The proposed scope is therefore to produce a subset of tables for pipe diameters up to those involved in H100 Fife, (up to 250 mm).Once the theoretical calculations are made, a selection of examples should be tested to compare the theoretical calculated results with actual measurements. One of the challenges expected here is that purge speeds are established in air, but the speeds will change dramatically as the air transitions to hydrogen. This may need to be noted in the updated tables.The scope will also look at options for setting up a training rig that can be used for validation measurements. The training rig is also to be scoped to provide demonstration tests of purging in hydrogen and also as a training rig to be used to train operators to carry out purging operations on relevant network sections.Proposed scope of workTheoretical work to update purge tables as per ML1 and ML2.Practical work to test a couple of instances of this on relevant network pipes to validate the theoryProviding assistance in re-writing the relevant sections of SGN documents (Schedule H of ML2)Scope up training opportunities for SGN commissioning teams to give exposure to hydrogen purgingDeliverablesThe deliverables for this work pack are a section of updated purge calculations that can be used in place of Table 56 in ML1 and Table 46 in ML2 up to 250 mm diameter. A short report will provide details of the theory used for this work and the evidence generated to support the theory that leads to the tabulated data and the purge calculator. Demonstration of purging with hydrogen, (using the purge vent from WP4) and scoping of training for H100 Fife commissioning teams.WP4: Hydrogen purge vent designBefore commissioning the H100 Fife network, vent stacks should be checked and agreed to be suitable for use with hydrogen. In particular, checks should be made to see if a new minimum vent speed is required to guarantee an acceptable safety factor in preventing burn back in hydrogen-air mixtures during venting operations.The purge standard IGE/SR/22 section 5.5.6 states that:a flame trap should not be used unless venting velocity is below 10 ms-1 for Natural Gas. Other gases may need a higher venting velocity. Flame speeds range from between 0.5 ms-1 for Natural Gas and 3.5 ms-1 for hydrogenThe laminar flame speed for Natural Gas is given as 0.5 ms-1 and the minimum vent velocity 10 ms-1. This implies a safety factor of 20. The laminar flame speed for hydrogen is given as 3.5 ms-1 with the same safety factor, this suggests a minimum vent velocity of 70 ms-1. A formal recommendation of a safety factor is not provided in the standards.The work will carry out experiments to review the possibility of burn-back during a purge. The vent speed will be varied and the degree of burn back measured for methane and hydrogen. This will allow comparisons to be made between existing vents and modifications to achieve similar performance in hydrogen. The results of these tests will be used to recommend the design of a modified purge stack for hydrogen. A vent stack with a restriction at the end will significantly increase the vent speed at the end of the stack, moving towards ensuring that the fastest speed during the purge is at the vent itself, potentially making the vent process safer. Production of a hydrogen vent stack will also facilitate the use of the Hydrogen Whistle, a passive hydrogen indicator being developed by Steer. The sample point on the stack could have a mount for the whistle that delivers an audible tone indicating real time the purge progress and confirmation of purge completion, minimising the volume of excess gas vented during a purge.Proposed scope of workScaled vent flow tests to assess likelihood and degree of burn back with various air-hydrogen mixesIgnition tests with vent pipes up to 2” during hydrogen purgesModification of vent stacks to mitigate burn back in the event of slow purgesTests using additional equipment such as the hydrogen whistle and pressure measurement to give real time, passive indication of the purge progressDesign of a clearly labeled hydrogen purge ventDeliverablesA purge vent suited for hydrogen and clearly marked to be different from a purge vent used for Natural Gas. A short report and demonstrations on the safe use of the stacks to be used in H100 commissioning operations.WP5: Mitigation of ignition mechanismsOver 750 purge operations have been carried out to date on the HyPurge project. During this time no unwanted or unexpected ignitions occurred, this is a small data set compared to the number of gas operations safely carried out each year. There is however, anecdotal evidence in the literature involving ignitions of hydrogen-air mixtures and this is a cause for concern regarding the safety of hydrogen in future. The exact nature of the ignition mechanisms is often unclear but suggestions include sparking from static electricity or heat or sparks generated by particulates such as rust impacting the pipe wall during high flow venting operations.Offshore oil and gas operations often specify non-sparking tools to be used in zoned areas where flammable atmospheres could be present.This work aims to look at realistic ignition mechanisms that are likely to exist during commissioning of H100 Fife and identify mitigation methods recognising that this is a trial and so the consequences of an unwanted ignition go beyond the safety of the individuals concerned. In the first instance we need to ensure the safety of all workers carrying out operations on the network. There then needs to be an additional level of confidence of safe operations to provide overall assurance for a transition to hydrogen as a domestic fuel.Proposed scope of workThis work will carry out a review of possible ignition mechanisms aims to develop an understanding of those ignitions in hydrogen and looks at methods to reduce the probability of unwanted ignitions occurring. This could include non-sparking tooling and anti-static clothing.Literature review of potential ignition mechanisms in gas networks (building on work already carried out for UK hydrogen projects).Examination of practices in other industries such as offshore sector in zoned areas.Review of tooling that is used during purging and identify where non-sparking alternatives are available.DeliverablesThe deliverable is a report on ignition mechanisms that may be applicable to H100 Fife and options of tooling to mitigate unwanted ignitions. Work Package 1: Project management, and communications The first work pack is the project management, regular updates and project reporting to wrap up the various work packs delivering the individual tool elements.The individual work packs have individual reporting requirements, it is expected that the individual reports would be collated together in the form of a concise final report. It is not expected that this will be a detailed theoretical report, but a collection of evidence to support the design of the various tools.Work Package 2 Flame arrestors (for use on bleed vents)The deliverable for this work pack is a short report detailing what is required / desirable in terms of flame arrestors and a market survey of what is currently available. The report will ideally include likely candidates for manufacturing flame arrestors purposed for hydrogen and suited to the gas market.Work Package 3: Calculation of purge tablesThe deliverables for this work pack are a section of updated purge calculations that can be used in place of Table 56 in ML1 and Table 46 in ML2 up to 250 mm diameter. A short report will provide details of the theory used for this work and the evidence generated to support the theory that leads to the tabulated data and the purge calculator. Demonstration of purging with hydrogen, (using the purge vent from WP4) and scoping of training for H100 Fife commissioning teams.Work Package 4: Hydrogen purge vent designA purge vent suited for hydrogen and clearly marked to be different from a purge vent used for Natural Gas. A short report and demonstrations on the safe use of the stacks to be used in H100 commissioning operations.Work Package 5: Mitigation of ignition mechanismsThe deliverable is a report on ignition mechanisms that may be applicable to H100 Fife and options of tooling to mitigate unwanted ignitions.
Abstract	The objectives of this Project are set out below: Investigation of flame arrestor development, (IGE/SR/22 requires flame arrestors to be used on vents that flow less than 10 m/s.) Investigations should be made to see if these need sourcing for hydrogen and if so, identifying where and how this can be done.Calculation of purge tables and purge calculators for hydrogen use as specified in ML2 and other SGN procedures.A purge vent design that is clearly different to a natural gas vent that can be used for hydrogen. The vent is not expected to include a flame arrestor but instead produce a flow speed sufficient to prevent burn back during a purge.Mitigating unwanted ignition mechanisms including non-sparking hand tools – review non-sparking tools used in the offshore environment and provide recommendations for H100
Publications	(none)
Final Report	(none)
Added to Database	14/10/22