Hydrogen Fires

Hydrogen is a popular energy storage medium and process element in the Industry. Hydrogen flames are virtually invisible in broad daylight which means extra risk for fire fighters.

Hydrogen applications

Gray Hydrogen is currently used for refining of oil and the production of fertilizers, food, (e.g., vegetable oil shortening), plastics, glass, pharmaceuticals, and semiconductors, etc. Currently, the most common form of Hydrogen that is produced worldwide is Gray Hydrogen. Gray Hydrogen is produced by a process called Steam Methane Reforming (SMR). SMR uses high-pressure steam, (H2O), which reacts with natural gas, (CH4), resulting in Hydrogen, (H2), and the Greenhouse gas, CO2.

Green Hydrogen is produced using sustainable electricity. The most common process uses electrolysis, in which water, (H2O), is split into Hydrogen, (H2), and oxygen, (O2), using Green electricity. Green Hydrogen, therefore, can make an important contribution for energy transition by CO2 reduction in the above-mentioned industries. Also, Hydrogen could replace the fuel in traditional industries that are currently heavily coal dependent, such as electricity generation and steel manufacturing. Currently, Hydrogen powered vehicles are in development as an alternative to fossil fuel powered ones. Electricity generation by wind farms and solar generation is forecast to increase sharply and Hydrogen can be an alternative fuel for power generation when wind and solar farms are not able to provide enough electricity due to weather conditions. With the growing use of Green Hydrogen in both industrial and commercial markets and with governments increasing incentives to move to cleaner fuels, there is the creation of a new worldwide supply chain, which offers many possibilities in the future.

The risks of Hydrogen

Hydrogen is a highly flammable gas, and it must be handled carefully during production, transport, and use. With a Lower Explosive Limit, (LEL), of 4 % and an Upper Explosive Limit, (UEL) of 75 %, Hydrogen can form explosive gas mixtures in a wide range of concentrations. Hydrogen is the lightest gas known and as the light and small H2 gas molecules diffuse rapidly, they can easily escape through valves and flanges, caused by leaking seals. In transport applications, Hydrogen is used under pressures up to 700 bar and these high pressures create additional risks. Hydrogen poses special threats to people and property, as it is odorless and colorless, and a typical risk of Hydrogen fires is that they are invisible. Only in the dark can a Hydrogen fire be seen as a bluish flame. For mitigating the risk of Hydrogen leaks and fires, we advise a combination of Gas Detectors, Ultrasonic Gas Leak Monitors and Flame Detectors. Ultrasonic Gas Leak Detectors respond to Hydrogen high pressure leaks. Gas Detectors should be used to detect diffused gas plumes. Both should respond before the Hydrogen ignites and provide a timely alarm to stop the leakage. If, however, the Hydrogen, after the start of the leakage immediately catches fire, the Flame Detector should be used as measure of last resort to detect the fire. 

Flame Detection suitable for monitoring Hydrogen Fires

A Hydrogen flame does not emit CO2, therefore, IR type Flame Detectors which specifically detect the CO2 band at 4.3 micron and not the 2.7-micron H2O band, are not suitable for detecting Hydrogen fires. UV/IR Flame Detectors, with a “water band” IR sensor at 2.7 micron are suitable for detecting Hydrogen fires. The UV/IR-210/1CZ from Sense-WARE uses an IR 2.7-micron water band sensor, combined with a solar blind UV-sensor, and therefore can detect Hydrogen fires. The UV/IR-210/1CZ is also virtually immune to unwanted alarm sources, such as arc welding, lightning, and sunlight.

Sense-WARE commissioned the Southwest Research Institute (SWRI) to do independent third-party testing of the UV/IR-210/1CZ UV/IR Flame Detector to determine the sensitivity to Hydrogen fires. The results can be found in the closing paragraph of this White Paper.

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