Hydrogen Blending
Accelerating to Net Zero with Hydrogen Blending Standards Development in the UK, Canada and the US - Part 1
Mar 2021
Publication
"Hydrogen is expected to play a critical role in the move to a net-zero economy. However large-scale deployment is still in its infancy and there is still much to be done before we can blend hydrogen in large volumes into gas networks and ramp up the production that is required to meet demands of the energy transport and industry sectors. KTN Global Alliance will host two webinars to explore these challenges and opportunities in hydrogen blending on the 2nd and 3rd March 2021.
Exciting pilot projects are being conducted and explored in the UK Canada and US states such as California to determine the technical feasibility of blending hydrogen into existing natural gas systems. Whilst the deployment of hydrogen is in its early stages there is increasing interest around permitting significant percentage blends of hydrogen into gas networks which would enable the carbon intensity of gas supplies to be reduced creating a new demand for hydrogen and with the use of separation and purification technologies downstream support the transportation of pure hydrogen to markets.
Gaps in codes and standards need to be addressed to enable adoption and there may be opportunities for international collaboration and harmonisation to ensure that best practices are shared globally and to facilitate the growth of trade and export markets. There is an opportunity for the UK Canada and US three G7 countries to work together and show market making leadership in key enabling regulation for the new hydrogen economy.
Delivered by KTN Global Alliance on behalf of the British Consulate-General in Vancouver and the UK Science and Innovation Network in Canada and the US these two webinars will showcase hydrogen blending pilot projects in the UK Canada and California highlighting challenges and opportunities with regard to standards development for hydrogen blending and supporting further transatlantic collaboration in this area. The events also form part of the UK’s international engagement to build momentum towards a successful outcome at COP26 the UN climate summit that the UK will host in Glasgow in November 2021. The webinars will bring together experts from industry academia and policy from the UK Canada and California. Attendees will have an opportunity to ask questions and interact using Mentimeter."
Part 2 Highlights and Perspectives from Canada and California can be found here.
Exciting pilot projects are being conducted and explored in the UK Canada and US states such as California to determine the technical feasibility of blending hydrogen into existing natural gas systems. Whilst the deployment of hydrogen is in its early stages there is increasing interest around permitting significant percentage blends of hydrogen into gas networks which would enable the carbon intensity of gas supplies to be reduced creating a new demand for hydrogen and with the use of separation and purification technologies downstream support the transportation of pure hydrogen to markets.
Gaps in codes and standards need to be addressed to enable adoption and there may be opportunities for international collaboration and harmonisation to ensure that best practices are shared globally and to facilitate the growth of trade and export markets. There is an opportunity for the UK Canada and US three G7 countries to work together and show market making leadership in key enabling regulation for the new hydrogen economy.
Delivered by KTN Global Alliance on behalf of the British Consulate-General in Vancouver and the UK Science and Innovation Network in Canada and the US these two webinars will showcase hydrogen blending pilot projects in the UK Canada and California highlighting challenges and opportunities with regard to standards development for hydrogen blending and supporting further transatlantic collaboration in this area. The events also form part of the UK’s international engagement to build momentum towards a successful outcome at COP26 the UN climate summit that the UK will host in Glasgow in November 2021. The webinars will bring together experts from industry academia and policy from the UK Canada and California. Attendees will have an opportunity to ask questions and interact using Mentimeter."
Part 2 Highlights and Perspectives from Canada and California can be found here.
Emissions control and performance evaluation of spark ignition engine with oxy-hydrogen blending
Mar 2018
Publication
Fast depletion of fossil fuels and their detrimental effect to the environment is demanding an urgent need of alternative fuels for meeting sustainable energy demand with minimum environmental impact. Expert studies indicate hydrogen is one of the most promising energy carriers for the future due to its superior combustion qualities and availability. The use of hydrogen in spark ignition internal combustion engine may be part of an integrated solution to the problem of depletion of fossil fuels and pollution of the environment. The broader flammability limits and fast flame propagation velocity of hydrogen ensures complete combustion of fuel and allows engine to be operated at lean ranges. Lean burn operation comparatively maintains NOx CO and HC emissions at a very low level. In the present work oxyhydrogen (HHO) gas is produced in leak proof plexiglass reactor by electrolysis of water using potassium hydroxide as electrolyte. The HHO gas generator is attached to a spark ignition engine currently operating on the road without any modifications of the engine. The HHO gas produced is then added to the air which is being drawn into the engine. Experiments were conducted on a 4-stroke single cylinder natural air cooled spark ignition engine to determine total fuel consumption specific fuel consumption air fuel ratio brake power and brake thermal efficiency and emissions CO CO2 O2 NOx HC at different loads with and without addition of HHO gas to gasoline for lower speeds ranging from 700 rpm to 1500 rpm. Also mileage tests were conducted to find the speed at which the fuel consumption is optimum.
Blended Hydrogen: The UK Public’s Perspective
Nov 2019
Publication
Hydrogen is increasingly being positioned as an important component of the UK’s Net Zero ambitions and commitments. In particular hydrogen could be an appropriate way to decarbonise the heat produced for domestic and industrial buildings. It is possible that hydrogen could replace natural gas in the UK gas network achieving key carbon emissions reduction targets while enabling homes to be heated to a similar level and standard as they currently are.<br/>In the interim small amounts of hydrogen will soon be blended into current natural gas supplies. The premise of this idea is to blend hydrogen into the existing gas network in small enough quantities to not require any adjustments to domestic cookers boilers and other gas-fired appliances but in large enough quantities to generate significant immediate reductions in carbon emissions. Three trials will take place between 2019 and 2022 as part of the HyDeploy project with the aim of demonstrating that hydrogen blending can occur at scale with no safety implications and no disruption to users.<br/>Public perceptions and acceptance of hydrogen will be pivotal in this scenario. At present there is very little indication of how acceptable hydrogen will be for heating homes and questions around safety cost and performance are only beginning to be understood and addressed.<br/>This report investigates public perceptions of blended hydrogen as a fuel for UK homes. In March 2019 we administered a survey to a sample (n=742) representative of the UK adult population in terms of age sex ethnicity and personal income. Our survey covered initial perceptions values and knowledge of hydrogen; the possibilities and pitfalls of hydrogen blending; public trust; and participants’ overall support for hydrogen. Key Findings and Conclusions and Recommendations for Policy and Practice follow immediately with the full report beginning on p.6.
A Statistical Assessment of Blending Hydrogen into Gas Networks
Aug 2021
Publication
The deployment of low-carbon hydrogen in gas grids comes with strategic benefits in terms of energy system integration and decarbonization. However hydrogen thermophysical properties substantially differ from natural gas and pose concerns of technical and regulatory nature. The present study investigates the blending of hydrogen into distribution gas networks focusing on the steady-state fluid dynamic response of the grids and gas quality compliance issues at increasing hydrogen admixture levels. Two blending strategies are analyzed the first of which involves the supply of NG–H2 blends at the city gate while the latter addresses the injection of pure hydrogen in internal grid locations. In contrast with traditional case-specific analyses results are derived from simulations executed over a large number (i.e. one thousand) of synthetic models of gas networks. The responses of the grids are therefore analyzed in a statistical fashion. The results highlight that lower probabilities of violating fluid dynamic and quality restrictions are obtained when hydrogen injection occurs close to or in correspondence with the system city gate. When pure hydrogen is injected in internal grid locations even very low volumes (1% vol of the total) may determine gas quality violations while fluid dynamic issues arise only in rare cases of significant hydrogen injection volumes (30% vol of the total).
Testing Programme for Hydrogen Tolerance Tests of Domestic and Commercial Natural Gas Appliances
Jan 2021
Publication
The THyGA project (‘Testing Hydrogen admixture for Gas Applications’) focusses on technical aspects and the regulatory framework concerning the potential operation of domestic and commercial end-user appliances with hydrogen / natural gas blends.<br/>The core of the project is a broad experimental campaign with the aim to conduct up to 100 hydrogen tolerance tests. In addition the technical status quo and present knowledge about hydrogen impact on domestic and commercial appliances are assessed and potential future developments of rules and standards are discussed. Also mitigation strategies for coping with high levels of hydrogen admixture will be developed. By this broad approach the project aims at investigating which levels of hydrogen blending impact the various appliance technologies and to which extent in order to identify the regime in which a safe efficient and low-polluting operation is possible.<br/>The series of public reports by the THyGA project starts with several publications from work package 2 which sets the basis for the upcoming results and discussion of the experimental campaign as well as mitigation and standardisation topics.<br/>This report D2.5 completes the series of public reports from work package 2. It explains the steps of development of the test programme for gas-fired appliance tests with hydrogen admixture and especially describes the exchange between the THyGA partners and the external stakeholders.<br/>The report also explains the process of acquisition of appliances to test and method of selecting appliances.
Indicative Analysis of Blending Hydrogen in Gas Networks
May 2020
Publication
Frontier Economics has been engaged by the Commonwealth Department of the Environment and Energy (now Industry Science Energy and Resources) (the Department) to undertake an indicative analysis of the economics of blending hydrogen in Australian natural gas distribution networks. Our analysis is limited to a specific gas distribution network servicing urban areas of Melbourne.
We have investigated the economics of blending hydrogen in a natural gas distribution network by examining a number of energy supply options including options that involve blending hydrogen. While we consider that these cases we have examined are useful for understanding the economics of hydrogen blending at low rates in Victoria and for understanding the factors that are likely to drive the economics of blending at higher rates or in other regions it cannot be assumed that the results we find for the cases we investigate will necessarily apply in other regions or for blending at other rates. This report should be read as an assessment of the specific cases we have investigated and our findings cannot necessarily be extended to other cases (such as other locations or other rates of blending)"
The full report can be found via the website of the Australian government at this link
We have investigated the economics of blending hydrogen in a natural gas distribution network by examining a number of energy supply options including options that involve blending hydrogen. While we consider that these cases we have examined are useful for understanding the economics of hydrogen blending at low rates in Victoria and for understanding the factors that are likely to drive the economics of blending at higher rates or in other regions it cannot be assumed that the results we find for the cases we investigate will necessarily apply in other regions or for blending at other rates. This report should be read as an assessment of the specific cases we have investigated and our findings cannot necessarily be extended to other cases (such as other locations or other rates of blending)"
The full report can be found via the website of the Australian government at this link
Differentiating Gas Leaks from Normal Appliance Use
Jun 2021
Publication
DNV has carried out an investigation into potential uses for smart gas meter data as part of Phase 1 of the Modernising Energy Data Applications competition as funded by UK Research & Innovation. In particular a series of calculations have been carried out to investigate the possibility of differentiating accidental gas leaks from normal appliance use in domestic properties. This is primarily with the aim of preventing explosions but the detection of leaks also has environmental and financial benefits.
Three gases have been considered in this study:
An examination of detailed historical incident information suggests that the explosions that lead to fatalities or significant damage to houses are typically of the type that would be more likely to be detected and prevented. It is estimated that between 25% and 75% of the more severe explosions could be prevented depending on which potential improvements are implemented.
Based on the conservative estimates of explosion prevention a cost benefit analysis suggests that it is justifiable to spend between around £1 and £10 per meter installed to implement the proposed technology. This is based purely on lives saved and does not take account of other benefits.
Three gases have been considered in this study:
- A representative UK natural gas composition.
- A blend of 80% natural gas and 20% hydrogen.
- Pure hydrogen.
- Small holes of up to 1 mm rarely reach flammable gas/air concentrations for any gas except under the most unfavourable conditions such as small volumes combined with low ventilation rates. These releases would likely be detected within 6 to 12 hours.
- Medium holes between 1 mm and 6 mm give outflow rates equivalent to a moderate to high level of gas use by appliances. The ability to detect these leaks is highly dependent on the hole size the time at which the leak begins and the normal gas use profile in the building. The larger leaks in this category would be detected within 30 to 60 minutes while the smaller leaks could take several hours to be clearly differentiated from appliance use. This is quick enough to prevent some explosions.
- Large holes of over 6 mm give leak rates greater than any gas use by appliances. These releases rapidly reach a flammable gas/air mixture in most cases but would typically be detected within the first 30-minute meter output period. Again some explosions could be prevented in this timescale.
An examination of detailed historical incident information suggests that the explosions that lead to fatalities or significant damage to houses are typically of the type that would be more likely to be detected and prevented. It is estimated that between 25% and 75% of the more severe explosions could be prevented depending on which potential improvements are implemented.
Based on the conservative estimates of explosion prevention a cost benefit analysis suggests that it is justifiable to spend between around £1 and £10 per meter installed to implement the proposed technology. This is based purely on lives saved and does not take account of other benefits.
HyDeploy Project - First Project Progress Report
Dec 2017
Publication
The HyDeploy Project seeks to address a key issue for UK customers: how to reduce the carbon they emit in heating their homes. The UK has a world class gas grid delivering heat conveniently and safely to over 83% of homes. Emissions could be reduced by lowering the carbon content of gas through blending with hydrogen. Compared with solutions such as heat pumps this means that customers would not need disruptive and expensive changes in their homes. This Network Innovation Competition (NIC) funded project seeks to establish the level of hydrogen that can be safely blended with natural gas for transport and use in a UK network.
Under its Smart Energy Network Demonstration innovation programme Keele University is establishing its electricity and gas networks as facilities to drive forward innovation in the energy sector. The objective of HyDeploy is to trial natural gas blended with potentially up to 20% volume of hydrogen in a part of the Keele gas network. Before any hydrogen can be blended with natural gas in the network the percentage of hydrogen to be delivered must be approved by the Health and Safety Executive (HSE). It must be satisfied that the approved blended gas will be as safe to use as normal gas. Any approval will be given as an exemption to the Gas Safety (Management) Regulations. These regulations ensure the safe use and management of gas through the gas network in the UK. The evidence presented to the HSE comprises critically appraised literature combined with the results from a specifically commissioned experimental and testing programme. Based on engagement with all local customers this includes detailed safety checks on the network appliances and installations at Keele. Subject to approval by the HSE the hydrogen production and grid injection units will be installed and an extensive trial programme of blending will be undertaken. If hydrogen were blended at 20% volume with natural gas across the UK it would save around 6 million tonnes of carbon dioxide emissions every year the equivalent of taking 2.5 million cars off the road.
This report and any attachment is freely available on the ENA Smarter Networks Portal here. IGEM Members can download the report and any attachment directly by clicking on the pdf icon above.
Under its Smart Energy Network Demonstration innovation programme Keele University is establishing its electricity and gas networks as facilities to drive forward innovation in the energy sector. The objective of HyDeploy is to trial natural gas blended with potentially up to 20% volume of hydrogen in a part of the Keele gas network. Before any hydrogen can be blended with natural gas in the network the percentage of hydrogen to be delivered must be approved by the Health and Safety Executive (HSE). It must be satisfied that the approved blended gas will be as safe to use as normal gas. Any approval will be given as an exemption to the Gas Safety (Management) Regulations. These regulations ensure the safe use and management of gas through the gas network in the UK. The evidence presented to the HSE comprises critically appraised literature combined with the results from a specifically commissioned experimental and testing programme. Based on engagement with all local customers this includes detailed safety checks on the network appliances and installations at Keele. Subject to approval by the HSE the hydrogen production and grid injection units will be installed and an extensive trial programme of blending will be undertaken. If hydrogen were blended at 20% volume with natural gas across the UK it would save around 6 million tonnes of carbon dioxide emissions every year the equivalent of taking 2.5 million cars off the road.
This report and any attachment is freely available on the ENA Smarter Networks Portal here. IGEM Members can download the report and any attachment directly by clicking on the pdf icon above.
Blending Ammonia into Hydrogen to Enhance Safety through Reduced Burning Velocity
Sep 2019
Publication
Laminar burning velocities (SL) of hydrogen/ammonia mixtures in air at atmospheric pressure were studied experimentally and numerically. The blending of hydrogen with ammonia two fuels that have been proposed as promising carriers for renewable energy causes the laminar flame speed of the mixture SL to decrease significantly. However details of this have not previously available. Systematic measurements were therefore performed for a series of hydrogen/ammonia mixtures with wide ranges of mole fractions of blended ammonia (XNH3) and equivalence ratio using a heat flux method based on heat flux of a flat flame transferred to the burner surface. It was found that the mixture of XNH3 = 40% has a value of SL close to that of methane which is the dominant component of natural gas. Using three chemical kinetic mechanisms available in the literature i.e. the well-known GRI-Mech 3.0 mechanism and two mechanisms recently released SL were also modelled for the cases studied. However the discrepancies between the experimental and numerical results can exceed 50% with the GRI-Mech 3.0 mechanism. Discrepancies were also found between the numerical results obtained with different mechanisms. These results can contribute to an increase in both the safety and efficiency of the coutilization of these two types of emerging renewable fuel and to guiding the development of better kinetic models.
Injecting Hydrogen into the Gas Network- A Literature Search
Jan 2015
Publication
Hydrogen injection into the GB gas network is a likely consequence of using excess offshore wind generated electricity to power large-scale onshore electrolysis plants. Government and DECC in particular now have a keen interest in supporting technologies that can take advantage of the continued use of the gas networks. HSE can contribute to the government’s Growth and Green agendas by effectively regulating and safely enabling this technology.
This report will allow HSE to regulate effectively by pulling together scientific and engineering knowledge regarding the hazards of conveying hydrogen/methane mixtures in network pipes and its use in consumer appliances into a single ‘state-of-play’ report. It enables Energy Division to consider and assess submissions for ‘gas quality’ exemptions to the Gas Safety (Management) Regulations 1996 (GSMR).
In particular the report has examined the following hazards:
This report will allow HSE to regulate effectively by pulling together scientific and engineering knowledge regarding the hazards of conveying hydrogen/methane mixtures in network pipes and its use in consumer appliances into a single ‘state-of-play’ report. It enables Energy Division to consider and assess submissions for ‘gas quality’ exemptions to the Gas Safety (Management) Regulations 1996 (GSMR).
In particular the report has examined the following hazards:
- conveyance of H2/CH4 mixtures in network pipes
- use of H2/CH4 mixtures in consumer appliances (domestic/commercial/industrial)
- explosion and damage characteristics (and ignition likelihood) of H2/CH4 mixtures
- effects on odourisation
Numerical Study on Combustion and Emission Characteristics of a PFI Gasoline Engine with Hydrogen Direct-Injection
Mar 2019
Publication
In this paper the effects of hydrogen blending radio and EGR rate on combustion and emission characteristics of a PFI gasoline engine with hydrogen direct-injection have been investigated by numerical modelling methods using a new generation of CFD simulation software CONVERGE. Results showed that compared with original engine hydrogen direct-injection PFI gasoline engine had a better performance on combustion characteristics but it also had a disadvantage of increasing NOx emissions. With the increase of hydrogen blending radio combustion duration shortened and CA50 advanced and was closer to TDC. And CO and THC emissions decreased however NOx emission increased. The variations of the combustion and emission characteristics followed by the increase of the EGR rate were exactly the opposite to the change of hydrogen blending radio. Considering both the combustion and emission characteristics using moderate EGR rate (15%~20%) under high hydrogen blending radio (15%~20%) condition can realize the simultaneous improvement of combustion and emission performance.
HyDeploy Project - Second Project Progress Report
Dec 2018
Publication
The HyDeploy project seeks to address a key issue for UK customers: how to reduce the carbon they emit in heating their homes. The UK has a world class gas grid delivering heat conveniently and safely to over 83% of homes. Emissions can be reduced by lowering the carbon content of gas through blending with hydrogen. This delivers carbon savings without customers requiring disruptive and expensive changes in their homes. It also provides the platform for deeper carbon savings by enabling wider adoption of hydrogen across the energy system.
This Network Innovation Competition (NIC) funded project seeks to establish the level of hydrogen that can be safely blended with natural gas for transport and use in a UK network. Under its smart energy network innovation demonstration programme Keele University is establishing its electricity and gas networks as facilities to drive forward innovation in the energy sector. The objective of HyDeploy is to trial natural gas blended with 20%mol of hydrogen in a part of the Keele gas network. Before any hydrogen can be blended with natural gas in the network the percentage of hydrogen to be delivered must be approved by the Health and Safety Executive (HSE). It must be satisfied that the approved blended gas will be as safe to use as normal gas. Such approval is provided as an Exemption to the Gas Safety (Management) Regulations. These regulations ensure the safe use and management of gas through the gas network in the UK. Following such approval hydrogen production and grid injection units are to be installed and an extensive trial programme undertaken. Blending hydrogen at 20%mol with natural gas across the UK would save around 6 million tonnes of carbon dioxide emissions every year the equivalent of removing 2.5 million cars from the road.
This report and any attachment is freely available on the ENA Smarter Networks Portal here. IGEM Members can download the report and any attachment directly by clicking on the pdf icon above.
This Network Innovation Competition (NIC) funded project seeks to establish the level of hydrogen that can be safely blended with natural gas for transport and use in a UK network. Under its smart energy network innovation demonstration programme Keele University is establishing its electricity and gas networks as facilities to drive forward innovation in the energy sector. The objective of HyDeploy is to trial natural gas blended with 20%mol of hydrogen in a part of the Keele gas network. Before any hydrogen can be blended with natural gas in the network the percentage of hydrogen to be delivered must be approved by the Health and Safety Executive (HSE). It must be satisfied that the approved blended gas will be as safe to use as normal gas. Such approval is provided as an Exemption to the Gas Safety (Management) Regulations. These regulations ensure the safe use and management of gas through the gas network in the UK. Following such approval hydrogen production and grid injection units are to be installed and an extensive trial programme undertaken. Blending hydrogen at 20%mol with natural gas across the UK would save around 6 million tonnes of carbon dioxide emissions every year the equivalent of removing 2.5 million cars from the road.
This report and any attachment is freely available on the ENA Smarter Networks Portal here. IGEM Members can download the report and any attachment directly by clicking on the pdf icon above.
Can the Addition of Hydrogen to Natural Gas Reduce the Explosion Risk?
Sep 2009
Publication
One of the main benefits sought by including hydrogen in the alternative fuels mix is emissions reduction – eventually by 100%. However in the near term there is a very significant cost differential between fossil fuels and hydrogen. Hythane (a blend of hydrogen and natural gas) can act as a viable next step on the path to an ultimate hydrogen economy as a fuel blend consisting of 8−30 % hydrogen in methane can reduce emissions while not requiring significant changes in existing infrastructure. This work seeks to evaluate whether hythane may be safer than both hydrogen and methane under certain conditions. This is due to the fact hythane combines the positive safety properties of hydrogen (strong buoyancy high diffusivity) and methane (much lower flame speeds and narrower flammability limits as compared to hydrogen). For this purpose several different mixture compositions (e.g. 8 % 20 % and 30 % hydrogen) are considered. The evaluation of (a) dispersion characteristics (which are more positive than for methane) (b) combustion characteristics (which are closer to methane than hydrogen) and (c) Combined dispersion + explosion risk is performed. This risk is expected to be comparable to that of pure methane possibly lower in some situations and definitely lower than for pure hydrogen. The work is performed using the CFD software FLACS that has been well-validated for safety studies of both natural gas/methane and hydrogen systems. The first part of the work will involve validating the flame speeds and flammability limits predicted by FLACS against values available in literature. The next part of the work involves validating the overpressures predicted by the CFD tool for combustion of premixed mixtures of methane and hydrogen with air against available experimental data. In the end practical systems such as vehicular tunnels garages etc. is used to demonstrate positive safety benefits of hythane with comparisons to similar simulations for both hydrogen and methane.
Autoignition of Hydrogen/Ammonia Blends at Elevated Pressures and Temperatures
Sep 2019
Publication
Hydrogen stored or transported as ammonia has been proposed as a sustainable carbon-free alternative for fossil-fuels in high-temperature industrial processes including power generation. Although ammonia itself is toxic and exhibits both a low flame speed and calorific value it rapidly decomposes to hydrogen in high temperature environments suggesting the potential use in applications which incorporate fuel preheating. In this work the rate of ammonia-to-hydrogen decomposition is initially simulated at elevated temperatures to indicate the proportion of fuel conversion in conditions similar to gas pipelines gas-turbines or furnaces with exhaust-gas recirculation. Following this different proportions of hydrogen and ammonia are numerically simulated in independent zero-dimensional plug-flow-reactors at pressures ranging from atmospheric to 50 MPa and pre-heating temperatures from 600 K to 1600 K. Deflagration of very-lean-to-fuel-rich mixtures was investigated employing air as the oxidant stream. Analyses of these reactors provide estimates of autoignition thresholds of the hydrogen/ammonia blends which are relevant for the safe implementation and operation of hydrogen/ammonia blends or pure ammonia as a fuel source. Further operational considerations are subsequently identified for using ammonia or hydrogen/ammonia blends as a hydrogen fuel carrier by quantifying residual concentrations of hydrogen and ammonia fuel products as well as other toxic emissions within the hot exhaust products.
Burning Velocity and Markstein Length Blending Laws for Methane/Air and Hydrogen/Air Blends
Sep 2016
Publication
"Because of the contrasting chemical kinetics of methane and hydrogen combustion the development of blending laws for laminar burning velocity ul and Markstein length for constituent mixtures of CH4/air and H2/air presents a formidable challenge. Guidance is sought through a study of analytical expressions for laminar burning velocity. For the prediction of burning velocities of blends six blending laws were scrutinised. The predictions were compared with the measured burning velocities made by Hu et al. under atmospheric conditions. These covered equivalence ratios ranging from 0.6 to 1.3 and the full fuel range for H2 addition to CH4. This enabled assessments to be made of the predictive accuracy of the six laws. The most successful law is one developed in the course of the present study involving the mass fraction weighting of the product of ul density heat of reaction and specific heat divided by the thermal conductivity of the mixture. There was less success from attempts to obtain a comparably successful blending law for the flame speed Markstein length Lb despite scrutiny of several possibilities. Details are given of two possible approaches one based on the fractional mole concentration of the deficient reactant. A satisfactory empirical law employs mass fraction weighting of the product ulLb.
HyDeploy Webinar - Public Perceptions
May 2020
Publication
HyDeploy is a pioneering hydrogen energy project designed to help reduce UK CO2 emissions and reach the Government’s net zero target for 2050.
As the first ever live demonstration of hydrogen in homes HyDeploy aims to prove that blending up to 20% volume of hydrogen with natural gas is a safe and greener alternative to the gas we use now. It is providing evidence on how customers don’t have to change their cooking or heating appliances to take the blend which means less disruption and cost for them. It is also confirming initial findings that customers don’t notice any difference when using the hydrogen blend.
As the first ever live demonstration of hydrogen in homes HyDeploy aims to prove that blending up to 20% volume of hydrogen with natural gas is a safe and greener alternative to the gas we use now. It is providing evidence on how customers don’t have to change their cooking or heating appliances to take the blend which means less disruption and cost for them. It is also confirming initial findings that customers don’t notice any difference when using the hydrogen blend.
Blending Hydrogen into Natural Gas Pipeline Networks: A Review of Key Issues
Mar 2013
Publication
The United States has 11 distinct natural gas pipeline corridors: five originate in the Southwest four deliver natural gas from Canada and two extend from the Rocky Mountain region. This study assesses the potential to deliver hydrogen through the existing natural gas pipeline network as a hydrogen and natural gas mixture to defray the cost of building dedicated hydrogen pipelines.
Combustion Features of CH4/NH3/H2 Ternary Blends
Mar 2022
Publication
The use of so-called “green” hydrogen for decarbonisation of the energy and propulsion sectors has attracted considerable attention over the last couple of decades. Although advancements are achieved hydrogen still presents some constraints when used directly in power systems such as gas turbines. Therefore another vector such as ammonia can serve as a chemical to transport and distribute green hydrogen whilst its use in gas turbines can limit combustion reactivity compared to hydrogen for better operability. However pure ammonia on its own shows slow complex reaction kinetics which requires its doping by more reactive molecules thus ensuring greater flame stability. It is expected that in forthcoming years ammonia will replace natural gas (with ~ 90% methane in volume) in power and heat production units thus making the co-firing of ammonia/methane a clear path towards replacement of CH4 as fossil fuel. Hydrogen can be obtained from the precracking of ammonia thus denoting a clear path towards decarbonisation by the use of ammonia/hydrogen blends. Therefore ammonia/methane/hydrogen might be co-fired at some stage in current combustion units hence requiring a more intrinsic analysis of the stability emissions and flame features that these ternary blends produce. In return this will ensure that transition from natural gas to renewable energy generated e-fuels such as so-called “green” hydrogen and ammonia is accomplished with minor detrimentals towards equipment and processes. For this reason this work presents the analysis of combustion properties of ammonia/methane/hydrogen blends at different concentrations. A generic tangential swirl burner was employed at constant power and various equivalence ratios. Emissions OH*/NH*/NH2*/CH* chemiluminescence operability maps and spectral signatures were obtained and are discussed. The extinction behaviour has also been investigated for strained laminar premixed flames. Overall the change from fossils to e-fuels is led by the shift in reactivity of radicals such as OH CH CN and NH2 with an increase of emissions under low and high ammonia content. Simultaneously hydrogen addition improves operability when injected up to 30% (vol) an amount at which the hydrogen starts governing the reactivity of the blends. Extinction strain rates confirm phenomena found in the experiments with high ammonia blends showing large discrepancies between values at different hydrogen contents. Finally a 20/55/25% (vol) methane/ammonia/hydrogen blend seems to be the most promising at high equivalence ratios (1.2) with no apparent flashback low emissions and moderate formation of NH2/OH radicals for good operability.
HyDeploy: The UK’s First Hydrogen Blending Deployment Project
Mar 2019
Publication
The HyDeploy project is the UK’s first practical project to demonstrate that hydrogen can be safely blended into the natural-gas distribution system without requiring changes to appliances and the associated disruption. The project is funded under Ofgem’s Network Innovation Competition and is a collaboration between Cadent Gas Northern Gas Networks Progressive Energy Ltd Keele University (Keele) Health & Safety Laboratory and ITM Power. Cadent and Northern Gas Networks are the Gas Distribution Network sponsors of the project. Keele University is the host site providing the gas-distribution network which will receive the hydrogen blend. Keele University is the largest campus university in the UK. Health & Safety Laboratory provides the scientific laboratories and experimental expertise. ITM Power provides the electrolyser that produces the hydrogen. Progressive Energy Ltd is the project developer and project manager. HyDeploy is structured into three distinct phases. The first is an extensive technical programme to establish the necessary detailed evidence base in support of an application to the Health & Safety Executive for Exemption to Schedule 3 of the Gas Safety (Management) Regulations (GS(M)R) to permit the injection of hydrogen at 20 mol%. This is required to allow hydrogen to be blended into a natural-gas supply above the current British limit of 0.1 mol%.
The second phase comprises the construction of the electrolyser and grid entry unit along with the necessary piping and valves to allow hydrogen to be mixed and injected into the Keele University gas-distribution network and to ensure all necessary training of operatives is conducted before injection. The third phase is the trial itself which is due to start in the summer of 2019 and last around 10 months. The trial phase also provides an opportunity to undertake further experimental activities related to the operational network to support the pathway to full deployment of blended gas. The outcome of HyDeploy is principally developing the initial evidence base that hydrogen can be blended into a UK operational natural-gas network without disruption to customers and without prejudicing the safety of end users. If deployed at scale hydrogen blending at 20 mol% would unlock 29 TWh pa of decarbonized heat and provide a route map for deeper savings. The equivalent carbon savings of a national roll-out of a 20-mol% hydrogen blend would be to remove 2.5 million cars from the road.
HyDeploy is a seminal UK project for the decarbonization of the gas grid via hydrogen deployment and will provide the first stepping stone for setting technical operational and regulatory precedents of the hydrogen vector.
The second phase comprises the construction of the electrolyser and grid entry unit along with the necessary piping and valves to allow hydrogen to be mixed and injected into the Keele University gas-distribution network and to ensure all necessary training of operatives is conducted before injection. The third phase is the trial itself which is due to start in the summer of 2019 and last around 10 months. The trial phase also provides an opportunity to undertake further experimental activities related to the operational network to support the pathway to full deployment of blended gas. The outcome of HyDeploy is principally developing the initial evidence base that hydrogen can be blended into a UK operational natural-gas network without disruption to customers and without prejudicing the safety of end users. If deployed at scale hydrogen blending at 20 mol% would unlock 29 TWh pa of decarbonized heat and provide a route map for deeper savings. The equivalent carbon savings of a national roll-out of a 20-mol% hydrogen blend would be to remove 2.5 million cars from the road.
HyDeploy is a seminal UK project for the decarbonization of the gas grid via hydrogen deployment and will provide the first stepping stone for setting technical operational and regulatory precedents of the hydrogen vector.
Non-combustion Related Impact of Hydrogen Admixture - Material Compatibility
Jun 2020
Publication
The present document is part of a larger literature survey of this WP aiming to establish the current status of gas utilisation technologies in order to determine the impact of hydrogen (H2) admixture on natural gas (NG) appliances. This part focuses on the non-combustion related aspects of injecting hydrogen in the gas distribution networks within buildings including hydrogen embrittlement of metallic materials chemical compatibility and leakage issues. In the particular conditions of adding natural gas and hydrogen (NG / H2) mixture into a gas distribution network hydrogen is likely to reduce the mechanical properties of metallic components. This is known as hydrogen embrittlement (HE) (Birnbaum 1979). This type of damage takes place once a critical level of stress / strain and hydrogen content coexist in a susceptible microstructure. Currently four mechanisms were identified and will be discussed in detail. The way those mechanisms act independently or together is strongly dependent on the material the hydrogen charging procedure and the mechanical loading type. The main metallic materials used in gas appliances and gas distribution networks are: carbon steels stainless steels copper brass and aluminium alloys (Thibaut 2020). The presented results showed that low alloy steels are the most susceptible materials to hydrogen embrittlement followed by stainless steels aluminium copper and brass alloys. However the relative pressures of the operating conditions of gas distribution network in buildings are low i.e. between 30 to 50 mbar. At those low hydrogen partial pressures it is assumed that a gas mixture composed of NG and up to 50% H2 should not be problematic in terms of HE for any of the metallic materials used in gas distribution network unless high mechanical stress / strain and high stress concentrations are applied. The chemical compatibility of hydrogen with other materials and specifically polyethylene (PE) which is a reference material for the gas industry is also discussed. PE was found to have no corrosion issues and no deterioration or ageing was observed after long term testing in hydrogen gas. The last non-combustion concern related to the introduction of hydrogen in natural gas distribution network is the propensity of hydrogen toward leakage. Indeed the physical properties of hydrogen are different from other gases such as methane or propane and it was observed that hydrogen leaks 2.5 times quicker than methane. This bibliographical report on material deterioration chemical compatibility and leakage concerns coming with the introduction of NG / H2 mixture in the gas distribution network sets the basis for the upcoming experimental work where the tightness of gas distribution network components will be investigated (Task 3.2.3 WP3). In addition tightness of typical components that connect end-user appliances to the local distribution line shall be evaluated as well.
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