Influência do pré-tratamento termoquímico de grama na produção de biogás

Abstract

The search for renewable energy sources is a scenario that is increasingly gaining prominence. Biogas appears as an alternative to minimize the impacts caused by animal husbandry waste contributing to the increase of energy in the energy matrix. There are residues that can be incorporated to the anaerobic process to potentiate the biogas production, denominated as substrates. Among them are the lignocellulosics that are mainly composed of cellulose, hemicellulose and lignin. The objective of this work was to evaluate the influence of thermo-chemical pre-treatment applied to grass residues for biogas production using three NaOH concentrations (1%, 3% and 5%) and two temperature ranges (28 and 100°C ). The composition of the grass used in the tests showed, on average, cellulose, hemicellulose and lignin contents of 34%, 24% and 11%, respectively, and low C/N ratio (15/1) for anaerobic digestion. The results indicated that the increase in temperature had a negative influence on the production of biogas due, according to data obtained in the literature, to the release of polyphenolic antioxidants. The results indicated that the highest specific production, with 340 mLNgSV-1 of biogas and 55% of methane, was obtained at a temperature of 28 °C and 3% of NaOH concentration.