EOPAA Research, Research Updates|

Photo of Doctor Richard BrownEOPAA members GR.Davis, Australian Botanical Products and ATTIA have donated significant quantities of eucalyptus, orange and tea tree oil respectively, to collaborative research between QUT and SCU examining the influence of essential oil additives to biofuel emission properties.

The Biofuel Engine Research Facility (BERF) (https://www.qut.edu.au/research/research-projects/biofuel-engine-research-facility) at the Queensland University of Technology is a state-of-the-art, fully automated, multi-fuel and multi-engine emission measurement facility. It currently has three different diesel engines mounted on engine dynamometers, all specifically designed to accommodate different types of alternative fuels. For this research project, a six-cylinder turbocharged diesel engine with a common rail injection system was used, which was coupled to an electronically controlled water brake dynamometer. The essential oils selected for investigation were Sweet Orange, Eucalyptus, and Tea tree oil. From a literature review, it was found that essential oils typically have quite a low cetane number. This number is a measure of the suitability of a fuel for use in a diesel engine. For this reason the engine tests used 5 and 10% blends of essential oils with diesel. From property test results, most of the properties such as higher heating value, viscosity and density of these essential oil blends were found quite similar to diesel fuel. Cetane and oxidation stability (shelf life) tests were carried out by Colorado State University under the supervision of Prof Anthony Marchese. One interesting observation was that, when Eucalyptus oil was blended with diesel, it improved the oxidation stability of diesel significantly. From the engine performance test, essential oil blends produced a similar level of engine power compared to neat diesel. The emission parameters were quite similar with reduction of oxides of nitrogen for most essential oil blends.

Photo of BERF engineOne of the interesting results found from this experiment is that Eucalyptus oil-diesel and Tea tree oil-diesel blends both have oxygen, however, Eucalyptus oil-diesel blends emit the lowest NOX whereas Tea tree oil-diesel blends emit a higher level of NOX. It is suspected that this is the result of complex oxygen bonding in the chemical structure of these two oils. To investigate further on this, another engine campaign has been planned in which fuel blends will be selected based upon oxygen content. Two oxygen contents have been selected, which are 2.2% and 5.5%. This campaign will start in mid-May. We will keep you posted on the results!

The market of essential oil is growing rapidly; in 2014 and 2015, the global demand grew from 165 to 179 kilo tonnes respectively [2, 3]. It is forecast that this demand will surge at a compound annual growth rate of 8.4% from 2016 to 2024 [3]. This rapid growth is influenced by the growing interest in the therapeutic characteristics of essential oils. However, in the health industry only the “therapeutic grade” quality of essential oils can be used; which leaves a significant volume of essential oils as a waste product which may fail to maintain the needed quality.

Previously, the notion of using essential oils in internal combustion engine has not been thought feasible. There have been a few studies, mainly in India, Singapore, Indonesia and South Africa which were focused on using these oils in compression ignition engines. From a literature search, the QUT project is the first research project undertaken which aims to evaluate the performance of Australian grown essential oils as diesel engine fuel.

BERF research locations

Figure: Location of research on use of essential oils in diesel engines. The current project collaboration of SCU/QUT is not shown.

[2] Grandview-Research. Essential Oil Market Analysis By Product (Orange, Corn Mint, Eucalyptus, Citronella, Pepper Mint, Lemon, Clove Leaf, Lime, Spearmint), By Application (Medical, Food & Beverage, Spa & Relaxation, Cleaning & Home) And Segment Forecasts To 2022 2015.

[3] Grandview-Research. Essential Oil Market Analysis By Product (Orange, Corn Mint, Eucalyptus, Citronella, Peppermint, Lemon, Clove Leaf, Lime, Spearmint), By Application (Medical, Food & Beverage, Spa & Relaxation, Cleaning & Home) And Segment Forecasts To 2024. 2016.

S M Ashrafur Rahman & Professor Richard Brown
Biofuels Engine Research Facility (BERF)
School of Chemistry, Physics and Mechanical Engineering
Science and Engineering Faculty
Queensland University of Technology
O Block, Level 7, Room O713-10, Gardens Point Campus
H/P: +61410193428

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