Hydrogen as a compressed gas

The containers used to store hydrogen as a compressed gas are similar in con struction to containers for compressed natural gas. These containers can be made from steel, aluminum, or composite materials. They must incorporate pressure relief devices so that the hydrogen is vented in the event that the tank is exposed to fire. 

Because hydrogen can be produced from a variety of feedstocks, at a wide range of sizes from city scale to household level, and delivered in various ways ranging from truck delivery of cryogenic liquid to gas pipeline delivery of compressed gas, there are many possible supply options. (To simplify the analysis, all supply options in this chapter assume delivery to motor vehicles of hydrogen as a compressed gas.) Near term supply options include ... 

Hydrogen can be stored as a compressed gas or liquid, or in reversible or alkali metal and chemical hydrides. The advantages of storing hydrogen as a compressed gas are simplicity, indefinite storage time and no purity limits on the hydrogen. Metal hydride compounds must have the following characteristics ... 

Silane. Silane is a colorless gas that is spontaneously flammable in air and slowly decomposed by water in the presence of aqueous alkah it is completely hydrolyzed to form hydrogen and siUcates. It is manufactured on a commercial scale and sold as a compressed gas in cylinders. It is prepared by the reaction... 

Hydrogen can be stored and transported as a compressed gas, a cryogenic liquid or in solids. Liquid hydrogen is closer to gasoline in the areas of volume and vehicular weight. In commercial aircraft, the takeoff... 

Hydrogen has been suggested as a convenient, clean-burning fuel. Hydrogen gas may be stored as a compressed gas or as a liquid, and it also has properties that make it suitable as a fuel for internal combustion engines in automobiles. 

Because oxygen is relatively insoluble in water, it can be collected by water displacement using the same apparatus employed to collect hydrogen (Figure 14.1). Oxygen is seldom prepared in the laboratory, though, because it is commercially available as a compressed gas in high-pressure steel cylinders. 

It is interesting to note that the most common method of onboard hydrogen storage in today s demonstration vehicles is as a compressed gas at pressures of roughly 700 bar. 

Use and exposure Hydrogen bromide is a colorless or faintly yellow-colored, corrosive gas it is highly toxic, with a sharp, unpleasant, irritating odor. It can also be found as a liquid, either as hydrobromic acid (hydrogen bromide dissolved in water) or as a compressed gas under pressure (anhydrous... 

Once the coal is converted to hydrogen, captured C02, and electricity, the C02 must be transported to the site of sequestration. C02 can be transported as a compressed gas, a liquid, a solid, or in a high-pressure supercritical state. If a pipeline right-of-way is available, economic considerations show a clear advantage for C02 transport in the supercritical state,- pipelines delivering nearly 50,000 t/day of supercritical C02 have operated safely... 

In the Clean Air Now (CAN) Solar Hydrogen Project near Los Angeles, a standalone electrolyzer is powered by photovoltaic cells with 48 kW total power. The produced hydrogen stored as a compressed gas (up to 34 MPa) is used to fuel three Ford Ranger trucks which are in commercial operation meeting the ULEV standard [89]. 

One of the biggest problems with hydrogen stored as a compressed gas is its very low volumetric density and the resulting need for large storage facilities. Liquefied hydrogen provides one solution to this problem. 

As a compressed gas, hydrogen can be transported by truck, ship, rail, or pipeline, or some combination of the above. 

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