Events / 6th Annual Bioindustrial Meeting: November 22-25, 2015 / Conference Abstracts / Poster Abstracts / Semi-Carbonization of Waste Coffee Grounds as an Energy Feedstock

Semi-Carbonization of Waste Coffee Grounds as an Energy Feedstock

Manzo Uchigasaki1, Kanto Komori1 and Motoyuki Okada2.
1Department of Bioenvironmental Engineering, Nihon University, Fujisawa, Japan.
2Finetech Co. Ltd., Fukushima Renewable Energy, Fukushima, Japan.

In Japan, the rate of dependence to coal-fired power generation is increasing under the influence of the great east Japan earthquake, and reduction of the greenhouse gas (CO2) amount of emergence which is increasing in connection with it has been a subject. Thus, we focus in biomass as a low-carbon emission resource to replace coal.

Semi-carbonization of spent coffee grounds is investigated as a means of valorizing commercial coffee waste. Coffee is the second largest globally traded commodity, as reported by the international coffee organization. Soluble coffee waste retains 65% of the raw coffee mass and is regularly disposed of in landfills where its environmental impact is experienced through oxygen intensive decomposition. Coffee grounds are obtained from large-scale food processing companies as a residue of instant coffee production in Japan.

In this work, waste coffee grounds are explored as an energy feedstock and an alternative processes for the production of valuable chemicals. In particular, focus in lignin related compound. The semi-carbonization, that is the pyrolysis in the temperature range between 300oC and 600oC, is conducted.

In order to determine the effect of temperature in lignin yields and composition, all experiments were run in three different temperatures and screw rates. The total lignin content was 51.3% (400 °C), 64.8% (500 °C) and 74.0% (600 °C) using Klason method. From the variation of heating value and energy yield of lignin yields with pyrolysis temperature, the semi-carbonization pyrolysis is found to be upgrading technology to convert the waste coffee ground into the high energy density fuel and valuable chemical.