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Internal pressure: At high hydrogen concentrations, absorbed hydrogen species recombine in voids to form hydrogen molecules (H 2), creating pressure from within the metal. This pressure can increase to levels where cracks form, commonly designated hydrogen-induced cracking ( HIC ), as well as blisters forming on the specimen surface, designated ...
An idealized reaction is: [1] + + The first review on HDO was published in 1983. [2] HDO is of interest in producing biofuels, which are derived from oxygen-rich precursors like sugars or lipids. An example of a biomass refining process employing hydrodeoxygenation is the NEXBTL process.
These reactions were demonstrated reversible without catalysts addition at relatively low hydrogen pressure and temperatures. The addition of TiCl3 was found to decrease the working temperature of the first dehydrogenation step of 50 K, [59] but no variations were recorded for the last two reaction steps. [51]
The addition of hydrogen to double or triple bonds in hydrocarbons is a type of redox reaction that can be thermodynamically favorable. For example, the addition of hydrogen to ethene has a Gibbs free energy change of -101 kJ·mol −1 , which is highly exothermic . [ 11 ]
The produced hydrogen and oxygen can permeate across the membrane, referred to as crossover. [15] Mixtures of both gases at the electrodes result. At the cathode, oxygen can be catalytically reacted with hydrogen on the platinum surface of the cathodic catalyst. At the anode, hydrogen and oxygen do not react at the iridium oxide catalyst. [15]
The pressure swing adsorption (PSA) process is based on the phenomenon that under high pressure, gases tend to be trapped onto solid surfaces, i.e. to be "adsorbed". The higher the pressure, the more gas is adsorbed. When the pressure is dropped, the gas is released, or desorbed.
An inert gas is a gas that does not readily undergo chemical reactions with other chemical substances and therefore does not readily form chemical compounds. Though inert gases have a variety of applications, they are generally used to prevent unwanted chemical reactions with the oxygen ( oxidation ) and moisture ( hydrolysis ) in the air from ...
Electrochemical hydrogen compressors have been proposed for use in hydrogen refueling stations to pressurize hydrogen gas for storage. They have also been applied into novel refrigeration systems to pressurize hydrogen for absorption into metal hydrides or to pressurize other working fluids (such as refrigerants) [5] as demonstrated by Xergy Inc. winners of the global GE's Ecomagination awards ...