Synthesis gas (or Syngas) is a gas mixture that contains varying amounts of hydrogen (H2), carbon monoxide (CO) and often some carbon dioxide (CO2) as well.
Production
Synthesis gas can be produced using a chemical process at various methods:
- from coal (using coal gasification or coal carbonization)
- from hydrogen and CO
- from methane and steam
Coal can be converted into syngas and methane, also known as town gas, via coal gasification. [1] Another method for conversion is low temperature and high temperature coal carbonization.[2]
CO2 can be split into CO and then combined with hydrogen (H) to form syngas. This method is ie being examined by the Solar Fuels-project of the Dutch Institute For Fundamental Energy Research[3] and by the Sunshine-to-Petrol project by Sandia National Laboratories. The Solar Fuels project envisions to produce CO from CO2, by treating this latter gas with microwave radiation.[4]. The method is very ecologic (as it uses waste CO² ie from fossil fuel power plants). The Sunshine-to-Petrol project simply uses a very high temperature to break up CO2 into CO. This is done using solar radiation (using a solar furnace. A specific device has been made to improve efficiency using this chemical process, and allow the production of syngas (by then combining the CO and the hydrogen -the latter also made using a very high temperature and not electrolysis of water-) in an automated way. This device has been called the Counter Rotating Ring Receiver Reactor Recuperator (or CR5)[5][6][7]
At high temperatures (700–1100 °C), steam (H2O) reacts with methane (CH4) to yield syngas.[8][9]
Usage
Coal gasification processes were used for many years to manufacture illuminating gas (coal gas) for gas lighting, cooking and to some extent, heating, before electric lighting and the natural gas infrastructure became widely available. The process can still be used today, yet it creates a significant amount of pollution.
Syngas can also be used as a fuel for vehicles. having less than half the energy density of natural gas, it needs a lot of pressurization (compression) and even then is still less potent than comparable other gaseous fuels (ie biogas, methane, ...).
Syngas is btw also useful for refining into variety of chemicals. These chemicals can then be converted in specific other chemicals, ie useful for making paint, plastics, ...(see http://en.wikipedia.org/wiki/Biobased_economy )
Syngas vs synfuel
Syngas should not be confused with synfuel (see see http://en.wikipedia.org/wiki/Synthetic_fuel). In general, fossil fuel reforming makes synfuel from fossil fuel (or natural gas) + hydrogen ( see http://en.wikipedia.org/wiki/Fossil_fuel_reforming ) Syngas however is made from hydrogen and CO (or CO² after having treated CO² with microwaves).
References
- ↑ "HFCIT Hydrogen Production: Coal Gasification". U.S. Department of Energy. 2008-12-12.
- ↑ Lee, Woon-Jae; Lee, Yong-Kuk (2001). "Internal Gas Pressure Characteristics Generated during Coal Carbonization in a Coke Oven". Energy & Fuels 15 (3): 618. doi:10.1021/ef990178a.
- ↑ DIFFER
- ↑ NWT magazine 6/2012
- ↑ [http://www.sandia.gov/mission/ste/stories/2008/August/Millerfinal.pdf Sunshine-to-Petrol project reference 1
- ↑ [http://energy.sandia.gov/wp/wp-content/gallery/uploads/S2P_SAND2009-5796P.pdf Sunshine-to-Petrol project reference 2
- ↑ [http://www.sciencedaily.com/releases/2007/12/071208150135.htm Sunshine-to-Petrol project reference 3
- ↑ see here
- ↑ Production of syngas using methane whereby no fossil fuels are used