Hydrothermal carbonization of olive tree pruning as a sustainableway for improving biomass energy potential: effect of reaction parameters on fuel properties

• Autor(a) principal: González-Arias, Judith
• Data de Publicação: 2018
• Outros Autores: Sánchez, Marta Elena, Martínez, Elia Judith, Covalski, Camila de Almeida, Alonso-Simón, Ana, González, Rubén, Cara-Jiménez, Jorge
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10198/23376
• topic: Bioconversion; Bioenergy; Biofuel; Combustion; Hydrochar; Hydrothermal carbonization; Olive tree pruning biomass

Hydrothermal carbonization (HTC) allows the conversion of organic waste into a solid product called hydrochar with improved fuel properties. Olive tree pruning biomass (OTP), a very abundant residue in Mediterranean countries, was treated by HTC to obtain a solid fuel similar to coal that could be used in co-combustion processes. Three different reaction temperatures (220, 250, and 280 °C) and reaction times (3, 6, and 9 h) were selected. The hydrochars obtained were extensively analyzed to study their behavior as fuel (i.e., ultimate, proximate, fiber and thermogravimetric analysis, Fourier-transform infrared spectroscopy (FTIR), activation energy, and combustion performance). The concentrations of cellulose, hemicellulose, and lignin in the samples depict a clear and consistent trend with the chemical reactions carried out in this treatment. Regarding O/C and H/C ratios and HHV, the hydrochars generated at more severe conditions are similar to lignite coal, reaching values of HHV up to 29.6 MJ kg-1. The higher stability of the solid is reflected by the increase of the activation energy (≈60 kJ mol-1), and ignition temperatures close to 400 °C. With this, HTC is a proper thermal treatment for the management of raw OTP biomass and its further conversion into a solid biofuel.