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:
“The windows were then closed and the steam turned on. There was a sign up saying that no one could smoke, but you couldn’t help it. You were lucky if you didn’t burst into flames.”
—Robert Benchley (1889–1945)
“Nothing so needs reforming as other people’s habits.”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)