Steam Reforming
Fossil fuels are the dominant source of industrial hydrogen. Hydrogen can be generated from natural gas with approximately 80% efficiency, or from other hydrocarbons to a varying degree of efficiency. Specifically, bulk hydrogen is usually produced by the steam reforming of methane or natural gas. At high temperatures (700–1100 °C), steam (H2O) reacts with methane (CH4) to yield syngas.
- CH4 + H2O → CO + 3 H2 + 191.7 kJ/mol
In a second stage, additional hydrogen is generated through the lower-temperature water gas shift reaction, performed at about 130 °C:
- CO + H2O → CO2 + H2 - 40.4 kJ/mol
Essentially, the oxygen (O) atom is stripped from the additional water (steam) to oxidize CO to CO2. This oxidation also provides energy to maintain the reaction. Additional heat required to drive the process is generally supplied by burning some portion of the methane.
Read more about this topic: Hydrogen Production
Famous quotes containing the words steam and/or reforming:
““If Steam has done nothing else, it has at least added a whole new Species to English Literature ... the booklets—the little thrilling romances, where the Murder comes at page fifteen, and the Wedding at page forty—surely they are due to Steam?”
“And when we travel by electricity—if I may venture to develop your theory—we shall have leaflets instead of booklets, and the Murder and the Wedding will come on the same page.””
—Lewis Carroll [Charles Lutwidge Dodgson] (1832–1898)
“Nothing so needs reforming as other people’s habits.”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)