Syngas
Syngas, or synthesis gas, is a mixture of hydrogen and carbon monoxide,[1] in various ratios. The gas often contains some carbon dioxide and methane. It is principally used for producing ammonia or methanol. Syngas is combustible and can be used as a fuel.[2][3][4] Historically, it has been used as a replacement for gasoline, when gasoline supply has been limited; for example, wood gas was used to power cars in Europe during WWII (in Germany alone half a million cars were built or rebuilt to run on wood gas).[5]
Production
Syngas is produced by steam reforming or partial oxidation of natural gas or liquid hydrocarbons, or coal gasification.[6]
C + H2O → CO + H2[1]
CO + H2O → CO2 + H2[1]
C + CO2 → 2CO[1]
Steam reforming of methane is an
- CH4 + H2O → CO + 3 H2
In principle, but rarely in practice, biomass and related hydrocarbon feedstocks could be used to generate biogas and biochar in waste-to-energy gasification facilities.[7] The gas generated (mostly methane and carbon dioxide) is sometimes described as syngas but its composition differs from syngas. Generation of conventional syngas (mostly H2 and CO) from waste biomass has been explored.[8][9]
Composition, pathway for formation, and thermochemistry
The chemical composition of syngas varies based on the raw materials and the processes. Syngas produced by coal gasification generally is a mixture of 30 to 60% carbon monoxide, 25 to 30% hydrogen, 5 to 15% carbon dioxide, and 0 to 5% methane. It also contains lesser amount of other gases.[10] Syngas has less than half the energy density of natural gas.[11]
The first reaction, between incandescent coke and steam, is strongly endothermic, producing carbon monoxide (CO), and hydrogen H
2 (water gas in older terminology). When the coke bed has cooled to a temperature at which the endothermic reaction can no longer proceed, the steam is then replaced by a blast of air.
The second and third reactions then take place, producing an
In order to produce more hydrogen from this mixture, more steam is added and the
- CO + H2O → CO2 + H2
The hydrogen can be separated from the CO2 by
Electricity generated from
Syngas that is not methanized typically has a lower heating value of 120 BTU/scf .[22] Untreated syngas can be run in hybrid turbines that allow for greater efficiency because of their lower operating temperatures, and extended part lifetime.[22]
Uses
Syngas is used as a source of hydrogen as well as a fuel.[12] It is also used to directly reduce iron ore to sponge iron.[23] Chemical uses include the production of methanol which is a precursor to acetic acid and many acetates; liquid fuels and lubricants via the Fischer–Tropsch process and previously the Mobil methanol to gasoline process; ammonia via the Haber process, which converts atmospheric nitrogen (N2) into ammonia which is used as a fertilizer; and oxo alcohols via an intermediate aldehyde.
See also
References
- ^ ISBN 978-0-07-137433-0.
- ^ "Syngas Cogeneration / Combined Heat & Power". Clarke Energy. Archived from the original on 27 August 2012. Retrieved 22 February 2016.
- ^ Mick, Jason (3 March 2010). "Why Let it go to Waste? Enerkem Leaps Ahead With Trash-to-Gas Plans". DailyTech. Archived from the original on 4 March 2016. Retrieved 22 February 2016.
- S2CID 94791479.
- ^ "Wood gas vehicles: firewood in the fuel tank". LOW-TECH MAGAZINE. Archived from the original on 2010-01-21. Retrieved 2019-06-13.
- S2CID 93526789. Archived from the original(PDF) on 3 March 2016.
- ^ "Sewage treatment plant smells success in synthetic gas trial - ARENAWIRE". Australian Renewable Energy Agency. 11 September 2019. Archived from the original on 2021-03-07. Retrieved 2021-01-25.
- S2CID 102872424.
- S2CID 265385618. Retrieved 29 December 2023.
- ^ "Syngas composition". National Energy Technology Laboratory, U.S. Department of Energy. Archived from the original on 27 March 2020. Retrieved 7 May 2015.
- OSTI 5364207.[page needed]
- ^ ISBN 978-3527306732.
- ^ "dieBrennstoffzelle.de - Kvaerner-Verfahren". www.diebrennstoffzelle.de. Archived from the original on 2019-12-07. Retrieved 2019-12-17.
- ^ EU patent 3160899B1, Kühl, Olaf, "Method and apparatus for producing h2-rich synthesis gas", issued 12 December 2018
- ^ "Sunshine to Petrol" (PDF). Sandia National Laboratories. Archived from the original (PDF) on February 19, 2013. Retrieved April 11, 2013.
- ^ "Integrated Solar Thermochemical Reaction System". U.S. Department of Energy. Archived from the original on August 19, 2013. Retrieved April 11, 2013.
- ^ Matthew L. Wald (April 10, 2013). "New Solar Process Gets More Out of Natural Gas". The New York Times. Archived from the original on November 30, 2020. Retrieved April 11, 2013.
- ^ Frances White. "A solar booster shot for natural gas power plants". Pacific Northwest National Laboratory. Archived from the original on April 14, 2013. Retrieved April 12, 2013.
- PMID 27714905.
- ^ US patent 5159900A, Dammann, Wilbur A., "Method and means of generating gas from water for use as a fuel", issued 3 November 1992
- ^ "Audi in new e-fuels project: synthetic diesel from water, air-captured CO2 and green electricity; "Blue Crude"". Green Car Congress. 14 November 2014. Archived from the original on 27 March 2020. Retrieved 29 April 2015.
- ^ ISBN 978-0-7918-4792-3.
- OCLC 1075942093.[page needed]
