Researchers at the Indian Institute of Technology Madras have developed a microwave process to produce biofuel from plastic waste, rice straw and sugarcane bagasse.
A team of three researchers led by R. Vinu, associate professor in Chemical engineering department, published its research work in peer-reviewed journal ‘Bioresource Technology and Fuel Processing Technology’.
Biomass, as a renewable source of carbon with immense potential, leaves no carbon footprint. “Agricultural waste products such as rice straw, sugarcane bagasse and wood chips can potentially serve as bio-oil producing biomass,” he said.
To make bio-oils competitive with fossil fuels, their oxygenate content must be reduced and hydrogen content increased. “Mixing biomass with hydrogen-rich materials during pyrolysis can conceivably make biomass derived bio-oil comparable to fossil-derived fuels in calorific value and chemical/physical properties,” Mr. Vinu explained.
When plastics, rich in hydrogen, are added to biomass they enable conversion to low-oxygenate bio-oils. Plastics also help to produce bio-oils with better properties besides tackling the waste. Bio-oils not only yield high energy and fuel but also reduce char formation.
The team microwaved a variety of biomass including rice straw, sugarcane bagasse, groundnut shells, wood sawdust and wood from Seemai karuvelam tree (Angaraji babul in Hindi, scientific name Prosopis juliflora) with two synthetic plastics, polypropylene and polystyrene.
“We believe that microwave-assisted pyrolysis process is a sustainable and energy efficient approach for resource recovery from a wide variety of wastes such as biomass agri residues, plastic wastes including disposed single-use plastics and non-reusable face masks, and a mixture of these,” Mr. Vinu added. GAIL (India) funded the research.
