Pressurized gaseous hydrogen

Stress-strain curves and microstructure from specimens of pipeline steels precharged with high-pressure gaseous hydrogen at 20,000 psi and 100°C for 8 days (a) API X70, (b) API X70/X80 type, and (c) API X70/X80 type. 

Summary of Mechanical Testing Results of Precharged Steels with High-Pressure Gaseous Hydrogen at 20,000 psi and 100°C for 8 Days... 

Fuel supply is usually from liquid hydrogen or pressurized gaseous hydrogen. For other fuels, a fuel processor is needed, which includes a reformer, water gas shift reactors and purification reactors, in order to decrease the amount of CO to an acceptable level (below a few tens of ppm), which would otherwise poison the platinum-based catalysts. This equipment is still heavy and bulky and limits the dynamic response of the fuel cell stack, particularly for the electric vehicle in some urban driving cycles. 

C San March and BP Somerday, Effects of high-pressure gaseous hydrogen on structural metals (2007-01-0433) , in SAE 2007 Transactions, SAE, Warrendale PA, 2008. 

Conventional fracture mechanics testing specimens, such as the compact, cantilever beam, modified bolt-load compact previously referred to as wedge-opening load (WOL), and contoured double-cantilever beam specimens, have been adapted for testing in both aqueous environments and in a high-pressure gaseous hydrogen environment. 

Fetch, N.O., Stables, P. Embrittlement of 4130 steel by low-pressure gaseous hydrogen. Nature 169, 842-843 (1952)... 

In the CVD coating process, the tools are heated in a sealed reactor with gaseous hydrogen at atmospheric or lower pressure volatile compounds are added to the hydrogen to supply the metallic and nonmetaUic constituents of the coating. For example, TiC coatings are produced by reaction of TiCl vapors with methane (CH and hydrogen (H2) at 900 to 1100°C. The reaction is... 

The UCKR.ON test problem assumes the simplest uniform surface implicitly, because adsorbed hydrogen coverage is directly proportional to the partial pressure of gaseous hydrogen and adversely affected by the partial pressure of the final products. Such a simple mechanism still amounts to a complex and unaccustomed rate expression of the type solved by second order algebraic equations. 

Fig. 8.105 Spring-loaded rig for sustained load testing of a steel specimen in gaseous hydrogen at high pressure (after Cavelt and van Ness )...

Equation (3.1.50) can be developed further. Consider once again cell (3.1.40), together with Eq. (3.1.49). We shall assume that hydrogen gas is under standard pressure in addition, metallic silver, solid silver chloride and gaseous hydrogen at standard pressure are selected as standards, that is... 

In practice, it is very often necessary to determine the potential of a test (indicator) electrode connected in a cell with a well defined second electrode. This reference electrode is usually a suitable electrode of the second kind, as described in Section 3.2.2. The potentials of these electrodes are tabulated, so that Eq. (3.1.66) can be used to determine the potential of the test electrode from the measured EMF. The standard hydrogen electrode is a hydrogen electrode saturated with gaseous hydrogen with a partial pressure equal to the standard pressure and immersed in a solution with unit hydrogen ion activity. Its potential is set equal to zero by convention. Because of the relative difficulty involved in preparing this electrode and various other complications (see Section 3.2.1), it is not used as a reference electrode in practice. 

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