Win-win research aims to provide solutions to landfilling waste while generating Australian-standard diesel

Published:29 October 2020

CQUniversity researchers Dr Jahirul Islam (top) and Mr Mehedi Hasan.

Could waste plastics one day power your vehicle?

That is the question researchers are currently trying to answer - in a project that looks at how waste plastics can be converted to Australian-standard diesel.

CQUniversity researcher Professor Mohammad Rasul said the project, which is led by Northern Oil Refinery (NOR) in partnership with CQUniversity, RMIT University and SYNBIO, is supported with a Commonwealth grant through the Cooperative Research Centres (CRC-P) Program.

“Fuel security and solid waste management are carbon management issues, and this project is addressing both of these,” Prof. Rasul explained.

CQUniversity has commissioned a pilot-sized, double-condenser, fixed-bed pyrolysis reactor with 20-litres of capacity that converts plastics wastes into crude pyrolytic oil using raw materials such as plastic bottles (milk, coke, and oil bottles), PVC pipes and general plastic waste normally diverted to landfill (i.e. packaging and used toys).

“Pyrolysis is the process of thermo-chemically decomposing carbon-rich materials at elevated temperatures in the absence of oxygen. This process typically occurs at temperatures above 350°C. In this process, the waste simultaneously undergoes physical and chemical changes. As no oxygen is present, the materials do not combust and instead thermally decompose into volatile gases, liquids, and solid material (char), project team member and Adjunct Professor Masud Khan, said.

Prof. Rasul is joined on the project by fellow CQU researchers Associate Professor Nanjappa Ashwath, Dr Jahirul Islam and Mr Mehedi Hasan from the Clean Energy Research Group, who are researching pyrolysis of wastes such as green waste, biomass, agricultural waste, organic industrial wastes, and waste tyres.

“About 80 percent of the volatile gases produced from pyrolysis can be condensed to form pyrolytic crude oil with the remaining non-condensable gases to be utilised as heat source in the process or blended into air mixtures for stationary combustion engines”, A/Prof Ashwath said.

Prof. Rasul explained that based on the recent national plastics recycling survey, about 2.5 gigalitres (GL) of diesel could be produced from non-recyclable waste plastics available in Australia each year, meeting about 10 percent of Australia’s demand.

“In addition, about 20 GL of diesel per annum can be produced from mixed waste currently landfilled in Australia, meeting about 70 percent of Australia’s demand,” Lead Research Chemist and project lead at NOR, Dr David Schaller, said.

“Pyrolytic crude oil derived from CQUs condenser is currently being refined at SYNBIO/NOR. The aim is to achieve sufficient conversion of the crude oil into a refined diesel that meets the Australian-standard fuel specifications for on-road use. Distillation followed by catalytic hydro-treatment are the technologies chosen to accomplish this”, Dr Schaller said.

RMIT University project team members Professor Karen Wilson and Professor Adam Lee are developing, and testing specialised catalyst materials aimed at tuning the fuel composition of the diesel product via ring opening mechanisms.

“This research project is the first-of-its-kind in Australia conducted at this scale and has the potential to create a new alternative-fuel-industry domestically, starting with waste conversion at the source (such as landfills and plastic waste collection centres) and transporting the crude oil to a centralised refinery for upgrading and distribution” Prof Rasul said.

Together, the group is striving to find sustainable solutions to dealing with landfill wastes.

CQUniversity’s facilities are also equipped with test engines to determine the performance, emissions and combustion characteristics of the diesel being produced.