The invention manufactures spent coffee grounds as biofuels, which dries the spent coffee grounds and the additive unit to constant weight. Mixing the spent coffee grounds and the additive in a weight ratio of 1:1 to 3:7 to form a mixture, and then forming the mixture into a predetermined shape. Finally, roasting the mixture at a temperature of no more than 300 ℃.

This technology fabricates biofuels by mixing spent coffee grounds, pine wood chips, and silver skin by torrefaction method. The mixture is palletized and torrefied under 200 to 300 ℃ condition. The heating value of the torrefied product reaches 6,516 cal/g which equals to the C level high volatile bituminous coal. Also, the burden to the environment can be release with the producing cost of US$188.

Waste energy (WtE), in addition to reducing waste disposal, can also be a source of renewable energy. Torrefaction is a very promising technology in WtE, especially in the recovery of valuable fuel oil from biomass and production of biofuels. The current market applications of biofuel products include food, boiler, electricity, renewable energy and energy products.