High temperature hydrogen

ISO 609. Determination of Carbon and Hydrogen High Temperature Combustion Method. 

Temperatures up to 1500 °C reduce the reversible thermodynamic potential for water decomposition from a room temperature value of 1.23 V to 0.7 V (43%). The cost of electrolytic hydrogen varies linearly with the potential of the cell at the current density being used, since cost of the electricity is the dominating item in the cost of electrolytic hydrogen, high-temperature steam electrolysis would greatly improve the economics. Heat is needed to maintain the temperature of the system, but heat costs only a third of the cost of electricity. So far, very high temperature cells are research items, but 1000 °C cells have been developed in Europe under the nickname Hot Elly. ... 

ISO. 201 lo. Coal and Coke—Determination of Carbon and Hydrogen, High-Temperature Combustion Method (ISO 625). International Standards Organization, Geneva, Switzerland. 

Production of oxygen and hydrogen High temperature steam electrolysis (HTE) technology R D in progress. 

In practice, no gas shows ideal behaviour, although helium, hydrogen and nitrogen approximate to ideality at high temperatures and low pressures. 

The conversion takes place at high temperature (820-850°C) and very short residence time (hundredth of seconds) in the presence of steam. The by-products are hydrogen, methane and a highly aromatic residual fuel-oil. 

Each of these elements can be extracted by reduction of the respective oxide at high temperature, using either carbon or hydrogen or by electrolysis of an aqueous solution of a salt of the required element. 

Different types of other coal liquefaction processes have been also developed to convert coals to liqnid hydrocarbon fnels. These include high-temperature solvent extraction processes in which no catalyst is added. The solvent is usually a hydroaromatic hydrogen donor, whereas molecnlar hydrogen is added as a secondary source of hydrogen. Similar but catalytic liquefaction processes use zinc chloride and other catalysts, usually under forceful conditions (375-425°C, 100-200 atm). In our own research, superacidic HF-BFo-induced hydroliquefaction of coals, which involves depolymerization-ionic hydrogenation, was found to be highly effective at relatively modest temperatnres (150-170°C). 

Nickel catalysts although less expensive than rhodium and platinum are also less active Hydrogenation of arenes m the presence of nickel requires high temperatures (100-200°C) and pressures (100 atm)... 

Bromoacetic acid can be prepared by the bromination of acetic acid in the presence of acetic anhydride and a trace of pyridine (55), by the HeU-VoUiard-Zelinsky bromination cataly2ed by phosphoms, and by direct bromination of acetic acid at high temperatures or with hydrogen chloride as catalyst. Other methods of preparation include treatment of chloroacetic acid with hydrobromic acid at elevated temperatures (56), oxidation of ethylene bromide with Aiming nitric acid, hydrolysis of dibromovinyl ether, and air oxidation of bromoacetylene in ethanol. 

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