Fueling a cleaner combustion

September 18, 2017

An additive for conventional fuel comprised of oxygenated organic compounds could help reduce the release of pollutants into the atmosphere during the combustion of fossil fuels. Researchers from KAUST have now established how these potential additives decompose under combustion-relevant conditions.

Selecting a suitable additive for a fuel blend hinges on a good understanding of its kinetic behavior under combustion conditions. Because of their ability to burn cleanly, organic compounds that contain more than 33% of oxygen by mass have recently emerged as prospective additives for conventional fuel blends.

Specifically, diethyl carbonate (DEC), which comprises 40.6% of oxygen by mass, is expected to facilitate the clean combustion of diesel fuels. Also, thanks to its high boiling point, it can reduce the volatility of blended fuels, which is desirable in warm weather to minimize vapor buildup that blocks fuel lines. However, its thermal decomposition remains poorly understood.

To fill this knowledge gap, Binod Raj Giri and coworkers have now evaluated the effects of pressure and temperature on the decomposition of DEC. With collaborators from the University of Miskolc, Hungary, the researchers assessed the decomposition kinetics of DEC by monitoring the evolution of ethylene, one of the reaction products, in real time using a tunable CO2 gas laser. "We carefully selected the laser wavelength to minimize interferences from other reaction intermediates," says PhD student, Muhammad AlAbbad, who performed these experiments at the University's low-pressure shock-tube facility.

The researchers combined experiments with theoretical calculations to "provide a detailed and reliable kinetic picture for the decomposition and its products," says Giri.

Giri's team had previously discovered that the carboxylate functional group had a small effect on the decomposition of organic esters called ethyl propionate and ethyl levulinate. "This motivated us to find out whether the same phenomenon would happen for DEC, which bears one more oxygen atom in its carbon skeleton than esters," he says.

The researchers found that the additional oxygen atom destabilized the carbonate by significantly lowering the reaction energy barrier, thereby increasing reactivity.

According to Giri, these findings will shed light into the applicability of biodiesel fuels, which consist of various methyl and ethyl esters, to modern diesel engines and engine hybrids. Also, they will help clarify the blending effect of esters and carbonates with conventional fuels.

Giri's team is currently investigating decomposition pathways for glycerol carbonate, which has a higher oxygen content than DEC. "This molecule might be even more attractive than DEC regarding soot reduction and environmental impact," he adds.
-end-


King Abdullah University of Science & Technology (KAUST)

Related Decomposition Articles from Brightsurf:

Endangered trees in Guam contribute to ecosystem diversity and health
Research at the University of Guam has shown that the decomposition of leaf litter from three threatened tree species releases nitrogen and carbon into the soil for use by other plants.

Biodiversity increases plant decomposition rate; should be factored into climate models, study finds
An international team of researchers published a meta-analysis of 176 studies investigating the effect of diverse leaf litter decay on ecosystems around the world on Sept.

Iron is to blame for carbon dioxide emissions from soil, says a soil scientists from RUDN
Iron minerals and bacteria can be the main agents of carbon dioxide emissions from the soil.

Could plants help us find dead bodies? Forensic botanists want to know
Search teams looking for human remains are often slowed by painstaking on-foot pursuits or aerial searches that are obscured by forest cover.

Studies shed new light on how biodiversity influences plant decay
Scientists have provided new insights on the relationship between plant diversity in forests and the diversity of organisms involved in their decay, such as bacteria and fungi.

Novel theory of climate dynamics: Three-pattern decomposition of global atmospheric circulation
Due to the lack of a complete theoretical system for climate prediction, the forecasting of drought and flood in summer of China has always been a major scientific problem for meteorologists.

New findings help design highly efficient metal oxide catalyst for ozone removal
A research team led by Prof. CHEN Yunfa from the Institute of Process Engineering (IPE) of the Chinese Academy of Sciences demonstrated the electron generation, compensation and transfer between ZnO and O3 through tuning crystal defects in ZnO.

Breaking down wood decomposition by fungi
Through a combination of lab and field experiments, researchers have developed a better understanding of the factors accounting for different wood decomposition rates among fungi.

Overcoming carbon loss from farming in peatlands
Miscanthus, willow found as good biomass crops to add carbon to vulnerable soils.

Interfacial chemistry improves rechargeability of Zn batteries
Prof. CUI Guanglei's group from the Qingdao Institute of Bioenergy and Bioprocess Technology of the Chinese Academy of Sciences has proposed new concepts concerning in situ formed and artificial SEIs as a means of fundamentally modulating the electrochemical characteristics of Zn.

Read More: Decomposition News and Decomposition Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.