6 - Hydrogen
Review articleOpen access
1980/01/01 Chapter DOI: 10.1016/B978-0-08-023269-0.50010-6
Publisher SummaryThis chapter explores the role of hydrogen in the gasification of coal and its production and transmission. Hydrogen can be used as a common energy carrier derivable from coal or nonfossil resources such as nuclear and solar energy. Hydrogen is naturally found in a chemically bonded form such as water or hydrocarbons and is stored in the form of energy sources such as fossil fuels, electric power, nuclear power, and solar power. Gasification of coal requires almost 50% of hydrogen, and it involves several stages. The higher the level of hydrogen present in the coal, the lesser is the amount of hydrogen needed to be introduced in subsequent processes. Most of the hydrogen currently produced is derived by the high temperature reaction of natural gas or naphtha with steam. Small quantities of high-purity hydrogen are produced by the electrolysis of water. Two major methods for producing hydrogen are electrolysis (liquid alkaline electrolytes) and thermochemical cycling. The direct use of electromagnetic energy could make hydrogen available at less cost. Storage in hydride compounds introduces a number of transition metals such as stainless steels and their alloys capable of absorbing hydrogen gas to form hydrides, which when heated slightly release the hydrogen. Transmission of hydrogen is associated with the gas mixture technique that is employed at low pressure.
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