Whereas hydrogen has benefits that specify its ongoing use as a putative inexperienced substitute for a lot of different fuels, it does current a fairly distinct set of security challenges. But it surely appears the dangers will be mitigated with adequate consciousness, and the deployment of applicable applied sciences and greatest practices, as Envirotec found in dialog with industrial security and gasoline detection knowledgeable Dräger. The agency assists organisations to work safely with hydrogen, and to equip their websites accordingly. Fuel detection techniques are a key ingredient.
Hydrogen’s specific power is with its versatility as a way to retailer, transport and distribute power over massive distances and between sectors – certainly, it’s the one at-scale expertise ready to take action. It may be produced wherever renewable power akin to wind or photo voltaic is generated, after which transported to the place it’s required. That is the perfect, no less than.
There are actually similarities between hydrogen and methane, and among the present infrastructure for pure gasoline will be repurposed for it. Each are explosive, for one factor. However there are key variations by way of their properties and the precise dangers they current. Adam Pope, Advertising and marketing Supervisor and Fuel Detection Lead with Dräger suggests this isn’t all the time obvious to operators and workers who’ve labored with pure gasoline or LPG. “They’ll perhaps have some thought concerning the Hindenburg catastrophe,” he muses, referencing the 1937 calamity that drew a line below an earlier period’s exploration of hydrogen as a gas, however they’ll usually be unfamiliar with hydrogen’s particular challenges, and the mandatory risk-mitigation methods.
For one factor, hydrogen’s flame traits are fairly distinct from different widespread fuels, in that it’s troublesome to detect with the bare eye in daylight (though it may be seen in darker circumstances). It additionally emits little or no warmth – so you’ll be able to’t really feel it till you’re in very shut proximity.
A technique it may be detected is by the electromagnetic radiation emitted when it burns – a signature that may be picked up by sure lessons of detector.
A number of the key threat components particular to hydrogen are listed within the facet panel (“Hydrogen threat components”, see finish of article). Its flammability and propensity to leak from constructions place a premium on high-integrity storage. And leak detection is an important component of safeguarding.
These threat components will clearly be unfamiliar the place hydrogen is a latest add-on to an organisation’s core experience. For instance, at a wind or photo voltaic power web site the place the operators have opted to provide hydrogen through electrolysis.
Factors of vulnerability within the worth chain are explored in an e-book from Dräger.1 Even the place present infrastructure will be tailored there will probably be very important new concepts to know. For instance, present gasoline pipelines, the place appropriate, would require new monitoring and upkeep regimes.
The e-book explains that “the chance of security incidents will increase when individuals are concerned”. The doc provides: “When heavy machines akin to vans are moved round, even minor bumps must be taken critically as they improve the chance of leakage.”
Profiling a web site
Gaining a full image of a web site’s dangers is an important precursor to designing mitigation measures – and requires an individualised threat evaluation, one thing Dräger’s literature recommends “earlier than becoming a member of the hydrogen financial system”. There isn’t a customary threat profile, seemingly, and the dangers manifest in several methods in every web site.
Hearth and gasoline mapping is one service the group introduces at this early stage, says Adam Pope, which can lead to a colour-coded 3d map of a web site supposed to afford a transparent understanding of the completely different dangers, and of the place leaked gases will journey in several circumstances.
Mounted gasoline and flame detection is the first means to guard a web site from explosion threat, by alerting operators to the presence of a leak, in order that premises will be evacuated and processes can doubtlessly be shut down.
A variety of various applied sciences is used right here, every with completely different strengths and weaknesses. Greatest observe includes a mixture of applied sciences, as Adam explains.
Three layers of safety
Level detectors are the core expertise for gasoline detection and kind the muse of most security techniques, he says. These will probably be situated anyplace there’s a hazard that gasoline can accumulate, akin to in confined areas. The draw back is that the gasoline should have the ability to make contact with the detector or it is likely to be missed.
The selection of sensor expertise is essential right here. As Adam factors out, the infrared sensors used to detect hydrocarbons are utterly blind to hydrogen. As an alternative, catalytic bead (CatEx) sensors, or electrochemical (EC) sensors, can be utilized right here. CatEx sensors provide a strong technique to detect hydrogen as much as the explosive restrict (i.e., under 100% LEL, the Decrease Explosion Stage), offering a quick response time. EC sensors are sometimes used the place decrease (ppm) focus ranges of hydrogen are to be detected, and in addition provide a quick response time and excessive accuracy.
An earlier warning of leakage is offered with ultrasonic detectors, to be deployed as an extra layer of detection the place applicable. These exploit the truth that hydrogen’s small molecule measurement leads to a high-frequency noise, wherever there’s a leak. The acoustic sensor can detect leaks occurring as much as 7 – 15 m away from the leak supply, and ship an on/off sign that can be utilized to set off an alarm or computerized shutdown of apparatus.
Ultrasonic detectors are good for outside areas, the place the wind may in any other case carry hydrogen away from level detectors.
The relative invisibility of hydrogen flames means an extra layer of detection can generally be applicable for a web site, within the type of hydrogen flame detectors. Two applied sciences seem to face out: UV/IR detectors, and 3IR.2 A standard choice for detecting hydrocarbon fires is a UV/IR detector, using one ultraviolet and one infrared sensor, and offering a swift response time however with some potential for false alarms, significantly when making an attempt to detect hydrogen.
To help with hydrogen detection particularly, Dräger has adopted a expertise referred to as “3IR” – so-named for its use of three separate IR sensors, and that is included within the firm’s Flame 1750 H₂ detector. The 3IR expertise produces a low charge of false alarms and a quick response – as Adam says, it could actually detect a 1m flame at a distance of as much as 40m, inside 5 seconds. It additionally offers a large discipline of detection compared to UV/IR. A case examine explores the small print of those claims, which can be the main target of a latest white paper.
Dräger’s flame-detection expertise associate Micropack performed the evaluation and used HazMap3D software program to mannequin a fancy industrial set up, and to point the detection protection out there with ten Dräger Flame 1750 H2 detectors. A color-coded evaluation displayed the detected fire-risk areas in inexperienced, and blind spots in crimson. And this seemingly confirmed that it offered 64% protection, with 36% of the goal areas remaining exterior the flame detector’s vary or obstructed. Compared, twenty UV/IR flame detectors in the identical set up achieved solely 44% protection, leaving 56% unprotected. The conclusion? 3IR expertise reduces price and will increase protection.
Multichannel method
Not like hydrocarbon combustion, which is often detected by way of CO₂ emissions, hydrogen flames are primarily recognized by the presence of water vapour — a distinction that seems central to this detection technique. The 3IR detector focuses on the two–4 µm area of the electromagnetic spectrum, the place hydrogen’s attribute spectral options are discovered. Every of the three separate IR sensors focuses on a particular area of this band: One focuses on the realm the place combustion signatures are strongest, and the opposite two present reference channels, to assist distinguish any detected hydrogen flame signature from different potential warmth sources within the neighborhood. By a steady comparability of the three alerts, the detector is ready to filter out sources of false positives akin to welding gear or daylight.
Quite a lot of points come into play when safeguarding a web site that makes use of or shops hydrogen in any means. When conducting a threat evaluation, Dräger advises on points akin to the position and selection of gasoline and flame detectors, along with issues akin to appropriate storage areas for hydrogen, and figuring out the place any gasoline will go if it escapes.
Safeguarding a web site may contain integrating gasoline and flame detectors with an inside alarm administration system, and different techniques that may, for instance, shut down processes which may carry an explosion threat when mixed with hydrogen.
Dräger offers an end-to-end service which additionally incorporates third-party merchandise akin to alarms, “to create a seamless security infrastructure”.
Whereas the panorama of dangers is likely to be unfamiliar to many at this level – or the world is within the strategy of getting acquainted with them – a constant message from Dräger appears to be that each one the dangers will be managed. With consciousness of the suitable safeguards, number of the precise applied sciences, and placing best-practice into motion, this promising clear power supply can turn out to be as routine as another type of gas.
Notes
[1] “Hydrogen: The best way to meet the security challenges.” Book out there from Dräger. https://www.draeger.com/Content material/Paperwork/Content material/hydrogen-safety-challenges-ebk-11064-en-master.pdf.
[2] “Detecting the Invisible: Understanding hydrogen flames and selecting the best detector”, PDF, out there from Dräger.
Hydrogen threat components – SIDE PANEL
The universe’s lightest component presents its personal distinctive set of threat components, a few of that are listed right here.
- Explosion threat: Whereas hydrogen just isn’t explosive by itself, it turns into extremely explosive when combined with air in sure concentrations. It additionally has a comparatively low ignition power. After manufacturing, hydrogen will are typically compressed to organize it for storage or transport, and this provides to the explosion threat. It additionally produces a a lot greater explosion than pure gasoline, with round 7x the explosion velocity.
- Leak threat: With its small molecule measurement, and low viscosity, hydrogen leaks extra readily than different fuels akin to methane. A container that’s “air-tight” for methane, won’t essentially be “air-tight” for hydrogen. This additionally means pipelines and different constructions must be engineered to hydrogen-ready specs, and it is going to be necessary to make sure there are common inspections of issues like joints in pipelines.
- Menace to constructions: The small measurement of molecules additionally accounts for hydrogen’s potential to embrittle constructions, by permeating their inside. To guard in opposition to this, storage tanks are typically fabricated from chrome steel or composites.
- Types gasoline pockets: Its lightness is one necessary distinction with methane, and the actual fact of hydrogen’s being lighter than air means leaks aren’t so simply detected at floor stage, even when harmful quantities is likely to be accumulating beneath a close-by ceiling, as Dräger’s literature explains. The position of gasoline detectors ought to mirror this.
- Odourless: Hydrogen is odourless, like methane. An odourant marker is added to the latter (mostly a specific mix of mercaptans), to get round this nasal invisibility. Such a risk is being investigated and trialled with hydrogen, however the outcomes are nonetheless awaited.
