Students of Indian Institute of Technology – Madras have come up with a solution to tackle non-recyclable plastic waste.
The five-member Team Enviro, which included a student from SSN College of Engineering, has developed a mobile solar-powered pyrolysis unit to convert plastic into oil. A kilogram of plastic can produce 500 to 700 ml of oil, depending on the quality of plastic used, the team said.
To conduct experiments, the team procured plastic waste from the Chennai Corporation garbage sorting centre in Velachery. “If we use virgin plastic of good quality, we can get as much as 800 ml of fuel. But the plastic we get from the sorting centre is often soiled and so the quantity of oil is less,” said K. Sivagami, a team member.
This fuel oil can be used in generators, motor boats and irrigation pumpsets. It takes 90 minutes from the time plastic waste is fed into the pyrolysis unit to the time it is converted into oil.
The unit can currently process only 5 kg of plastic at a time. The unit uses as much as 3-4 units of power/kg/hour.
“Large-scale pyrolysis units have been unsuccessful due to issues like transporting plastic waste. We designed a mobile, transportable unit that can be installed in sorting centres at the ward or zonal garbage segregation centres,” said G. Divya Priya, a post-doctoral research scholar involved in the project.
The residue (sludge) generated during the burning process is compressed and made into light charcoal briquettes, which can also be reused to run the unit. The briquettes can also be used to power medium and small-scale industrial units, said team mentor Indumathi M. Nambi, professor, Environmental and Water Resources Engineering Division.
The unit was demonstrated at the UN World Environment Day exhibition in New Delhi earlier this year. It has also won the team the innovation excellence award and funding to incubate a start-up at the institute’s research park. Already NGOs and some community-level organisations have approached the team. Chennai and Thoothukudi corporations have also expressed interest in the product.
“We have submitted a proposal for building a pilot-scale plant for a municipality or corporation with a daily generation capacity of 250kg of non-recyclable plastic waste,” Ms. Sivagami said.