Researchers at the University of Saskatchewan (USask) in Canada have discovered a way to help utilise agricultural waste to produce pellets.
Tumpa Sarker, a PhD candidate in USask’s department of chemical and biological engineering, has found that heating canola meal, canola hull, and oat hull before compressing it yields a higher quality pellet with lower moisture content and volume, and higher energy content and density. The resulting product has a value similar to coal, Sarker discovered.
“We all have this carbon stored in forests, and plant and agricultural residue,” said Sarker. “We are looking at how to use it in place of fossil fuels to generate energy.”
Many farming by-products are currently left out in the field to rot. The resulting methane releases large amounts of greenhouse gas. Compacting plant material into small pellets increases its density up to 10 times, making it more economical to transport and store.
According to USask, Canada currently exports up to 4 million bio-pellets to Europe annually, the majority of which are manufactured using forestry by-products. While some Saskatchewan firms use agricultural waste in animal feed, none are converting this material into bio-pellets.
Dr Ajay Dalai, Sarker’s PhD supervisor and Canada Research Chair in Bioenergy and Environmentally Friendly Chemical Processing, said: “There is a really huge market for this (biofuel). The world is hungry for reducing CO2 emissions and increasing the use of non-fossil fuels for generating power and heat.
“These pellets are a great solution. They have low net CO2 emissions. This could bring money for (agricultural) producers and generate local employment.”
The treatment process used, called torrefaction, involves heating the biomass at temperatures between 200 and 300oC in an inert environment (an environment free of oxygen and CO2).
Dalai said the objective of the research, which is supported by Agriculture and Agri-Food Canada as part of the Biomass Canada Cluster and Saskatchewan’s Ministry of Agriculture, is to develop a technology that can be picked up by a local company then used to produce high-quality bio-pellets for energy applications.
“Europe is very aggressive in reducing their emissions,” said Dalai. “So, that would be a major market if we had a local company making these pellets and exporting them abroad.”
Dalai and Sarker are now focusing on finding an environmentally friendly binding agent that will make the pellets more durable and resistant to absorbing moisture during shipping.