Hydrogen as a gas is colorless, odorless and tasteless. The Hydrogen content of atmospheric air at sea level is 0.5 ppm. It is the lightest of all elements and will rise in a confined space and displace Oxygen to create Oxygen deficient or an explosive atmosphere.
Hydrogen is a flammable gas and will burn in air with a pale blue flame that is almost invisible in well lighted areas. A single volume of liquid Hydrogen expands to about 850 volumes of gas at standard temperature and pressure when vaporized. At 7,000 ft elevation, this expansion rate is increased to approximately 1,000 volumes of gas at standard temperature.
Concentrations of Hydrogen in air between 4% and 75% by volume can be easily ignited by a low energy spark which is as small as 20 micro joules. Smoking, open flames, spark producing equipment are prohibited in areas where Hydrogen is stored, handled or used.
Hydrogen is able to reduce the performance of some containment and piping materials, such as carbon steel. Because of its small molecular size, Hydrogen can easily pass through porous materials and is capable of being absorbed by some containment materials, which can result in loss of ductility or embrittlement. At elevated temperatures, this process is accelerated because of the possibility of Hydrogen embrittlement of some materials, piping and component materials that are not subject to this form of degradation should be selected. Recommended materials include 300-series stainless steels, copper, and brass.
Owing to the extremely low temperature of liquid Hydrogen (-423oF/-253oC), air will condense on exposed liquid Hydrogen surfaces such as vaporizers and piping.
All Hydrogen storage and handling equipment must be equipped with a common grounding system to prevent the buildup of static electricity and a resultant spark. Because of the extremely low energy required to ignite flammable mixtures of Hydrogen gas, one must exercise caution when using Hydrogen around electrical equipment. All flexible hoses and piping systems must be electrically grounded.
It is very important to secure all compressed gas cylinders in an upright position so that they cannot be knocked over. Never crack a Hydrogen cylinder valve to remove dust or dirt from fittings prior to attaching a regulator. This practice with Hydrogen renders a risk of self-ignition.
To detect a small, local Hydrogen fire (the flame is nearly invisible), use a piece of tissue paper on a stick; the paper will readily ignite when it contacts a flame. If fire is present, then the following should be performed:
1. Shut off the Hydrogen source.
2. Let the fire burn itself out. (If the flame is snuffed out, it may reignite and cause greater damage.)
3. If you have received hands-on training in the proper operation of a water fire extinguisher then you may use water spray to thermally protect people and other equipment if the fire is hot enough. However, a venting Hydrogen flame cannot normally be extinguished with water. The basic idea is to keep the surrounding area and equipment cool with large quantities of water in the form of a spray.
4. Initiate the emergency plan (which should include calling the fire department) and make the required emergency contacts.
6.3 m3 capacity cylinder at 130-140 kg/cm2 pressure
H2 in mixture with inert gases is used to obtain a reducing atmosphere in the metallurgical industry, such as heat treating steel and welding. Also used in annealing (Heat treatment process that alters the microstructure of a material) stainless steel alloys, magnetic steel alloys, sintering and copper brazing. Used as a “shield gas” in welding methods such as “atomic hydrogen welding”.
In chemical industry, H2 is used as a raw material in the chemical synthesis of ammonia, methanol, hydrogen peroxide, polymers and solvents. They are also employed to “hydrogenate” non-edible oils for soaps, plastics, ointments and other speciality chemicals.
In refineries, it is used to remove sulphur in the form of H2S (Hydro-desulphurization).
Also used in :
Hydro cracking (It is a catalytic process to convert oil to gasoline, diesel, chemical feed stocks which prevents coking of catalyst).
Hydrogenation (In the production of oxy-alcohols, higher fatty amines, poly olefins, poly butadiene etc.
H2 is used to cool alternator to maintain efficiency of power plants.
H2 as a “clean energy carrier” is used in “fuel cells” to generate electric power. Used as “rotor coolant” in electrical generators at power stations.
H2 is used as fuel in spacecrafts, rockets and power for life-support systems (to recycle waste water etc).
H2 is used to hydrogenate unsaturated fatty acids and produce solid fats for margarine(just like butter but having less calories and saturated fat content) and other food products like soya bean, fish, cotton seed, corn, peanut. It is also used to convert them into semi-solid food materials.
H2 is used in float glass manufacturing process; H2/N2 is used to prevent oxidation of the large tin bath. Also used for heat treatment of the hollow glass and pre-forms optic fibers.
H2 is used for the production of plastics, polyester and nylon.
H2 is used as a “carrier gas” (mobile phase) for active trace elements such as Arsine and Phosphine (PH3), in the manufacture of semi-conducting layers in integrated circuits. H2 is used as a “scavenger gas” in atmosphere for soldering and annealing of copper films.
H2/N2 (Forming gas) is used for complete removal of O2 (purification of gases).
H2 is a carbon-free energy source used in the fuel cells.
H2 is used as carrier gas in gas chromatography and in various analytical instrument applications, as a fuel component of combustion gases for Flame Ionization (FID) and Flame Photometric (FPD) detectors.
H2 is widely used as a lifting agent in balloons and airships.
“Nuclear fuel industry” uses hydrogen as a protective atmosphere in the fabrication of fuel rods. Used as a “tracer gas” for minute “leak detection”. Tritium (Hydrogen-3) is used in the production of “hydrogen bombs”. H2 allows food package leak testing. H2 is used in the processing of fossil fuels.