Researchers from KAUST’s Clean Combustion Research Centerin Saudi Arabia, with colleagues at the University of Miskolc in Hungary, have found that glycerol carbonate produced from the crude glycerol byproduct of biodiesel production has great potential for enabling cleaner combustion as a fuel additive.

Crude glycerol of about 10–20% by volume appears as a byproduct in conventional biodiesel production. Increasing demand for biodiesel has led to a substantial increase of glycerol supply in the global market and a dramatic fall in the price of glycerol.

One potential way to deal with the crude glycerol overflow is to convert it to glycerol carbonate (GC) and use GC as a fuel or fuel additive. Prior studies have indicated that carbonate esters can significantly reduce particulate emissions during engine combustion. In this work, we have explored possible reaction pathways in the initial stage of glycerol carbonate pyrolysis.

Ab initio/RRKM-master equation methods are employed to differentiate various reaction pathways and to obtain the pressure- and temperature-dependence of the major channels.

We have found that glycerol carbonate decomposes almost exclusively to produce CO₂ and 3-hydroxypropanal over 800–2000 K and radical forming channels are unimportant. As 3-hydroxypropanal is one of the main products of GC decomposition, and aldehydes are known to have a very high impact on soot reduction, we conclude that GC has great potential for cleaner combustion as a fuel additive.

—Szőri et al.

Resources

• Szőri, M., Giri, B. R., Wang, Z., Dawood, A. E., Viskolcz, B. & Farooq, A. (2018) “Glycerol carbonate as a fuel additive for a sustainable future.” Sustainable Energy & Fuels 2, 2171-2178 doi: 10.1039/C8SE00207J