Students make pellets from coffee grounds as fuel

Using coffee grounds and sawdust, four young people from the Coffuel project create pellets to burn in industrial boilers to replace coal, firewood, and gas.

The Coffuel project was carried out by Nguyen Xuan Bao, School of Chemistry and Life Sciences, Hanoi University of Science and Technology, and a group of friends Pham Minh Long Hai, Bui Nguyen Khanh Linh, and Nguyen Minh Anh.

Biomass pellets from coffee grounds. — Biomass pellets from coffee grounds made by Coffuel group. Photo: *Research team*

Bao said the idea for this agricultural by-product was sparked during a trip to a coffee plantation in Dak Lak, where he realized "there was too little value from coffee trees being utilized". In February 2022, the group began looking for a solution to exploit energy from coffee grounds.

The group collects grounds from coffee processing plants and sawdust from woodworking workshops. The coffee grounds are treated for odor, excess essential oils and substandard size scraps are removed. The sawdust is screened for size, cleanliness and moisture. The raw materials are fed into an industrial rotary dryer to bring the moisture content to about 8-10%.

After the drying stage, the mixture is mixed at a ratio of 50 - 55% coffee grounds, 42 - 44% sawdust, and heated to maintain the right humidity and avoid mold. The temperature is maintained at 75 - 80 degrees to melt the tannin compounds in the coffee grounds, combined with the high lignin content of sawdust to form a natural adhesive.

In the final step, the raw material will go through a high pressure pressing process and be pressed into pellets with an output mold. The pressing pressure is adjusted according to the form of industrial pellets or household pellets.

"Pellet performance is 120% that of wood pellets and ash is reduced by 90% compared to traditional coal," said Pham Minh Long Hai, a team member.

Coffuel project won the Champion of the HUST Technology Startup Innovation Competition (Techstart 2023).

Coffuel project won first prize in the technology startup competition. — Coffuel project won the championship in the technology startup competition. Photo: *Ha An*

Associate Professor Dr. Nguyen Phong Dien, Vice President of Hanoi University of Science and Technology, highly appreciated the idea and proposed solutions that benefit the community. This is also a promising research direction for commercializing products.

Nhu Quynh

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