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Nothing goes to waste with CQUni’s latest clean energy project

Published:06 September 2019

L-R Associate Professor Mohammad Rasul, Associate Professor Nanjappa Ashwath and PhD students Mohammad Hasan and Mohd Rahman.

Australia produces tens of millions of tonnes of waste each year, and this could be effectively used as a source of ‘renewable’ energy.

When the climate policy settings and economics line up, it will be crucial to know the most viable process of producing fuel from farm harvest by-products and city landfill staples like green waste, rotting waste, tyres and hard plastics,

That’s why CQUniversity’s Clean Energy researchers have commissioned a new ‘pyrolysis’ test rig which is designed to provide this valuable data.

Waste shredded into 5 mm pieces is fed into the test rig’s high-temperature zone (reactor), in the absence of oxygen, to produce three valuable products - syngas, biochar and biooil.

Syngas can fuel a generator to produce electricity, biooil can be converted into an alternative diesel fuel, and biochar can be used to condition the soils on farms, or used in the synthesis of fuel cells to store energy from solar panels.

Associate Professor Mohammad Rasul says his postgraduate students will focus on producing data on a range of inputs and output variables.

“Even a mix of municipal landfill wastes could be used in the process,” he says.

“The pyrolysis machine is worth around $100 000 and it’s one of only a few of this scale in Australia.

“The beauty of this machine is that industries - either locally or anywhere from Australia – can come to us if they generate considerable amounts of waste from their normal operations.

“The test plant will help forecast how much of each of biochar, biooil and syngas can be produced from their waste."

Associate Professor Nanjappa Ashwath says a large proportion of agricultural ‘biomass’ (such as corn stalks, rice husk) is wasted when it could be better used for bioenergy production.

He said Australia should also consider establishing selected plant species on marginal lands, solely for biofuel production.

Plants, such as the beauty leaf tree (BLT), pongamia and agave, should be considered as they help re-green degraded land and provide sought-after biofuel.

“When beauty leaf trees are grown, the ground will be covered with fruits twice a year. These fruits contain oil-rich seeds (up to 60% oil) which can be squeezed for extraction. This oil can be converted as biodiesel or it can be used in the production of medicinal oil (Tamanu oil), soaps and shampoos.

"The shell and the press cake, which are the by-products of oil extraction, can be utilised in the pyrolysis process to produce syngas, biooil and biochar, so you are making use of the main oil as well as the waste.”

Associate Professor Rasul adds that the clean energy researchers "acknowledge and thank CQUni's Research Division, School of Engineering and Technology, and Centre for Intelligent Systems for supporting this infrastructure".