Produção de hidrogênio e metano a partir da vinhaça de cana-de-açúcar em reatores anaeróbios de leito fluidizado

Abstract

The concern for environmental issues has become increasingly clear, leading to the search for new clean and sustainable technologies. In this context, it appears as an alternative the production of hydrogen and methane from anaerobic processes. One of the byproducts of this renewable source is vinasse and the conversion of this material into fermentable sugars by the anaerobic digestion process is considered a promising alternative to increase production of another source of clean energy, the biogas. In this context, the objective of this study was to apply the agro-industrial residue from sugarcane processing in anaerobic reactors for the biological production of hydrogen and methane, studying, simultaneously, the acidogenic phase and methanogenic phases. The reactors were operated under progressive increase of volumetric organic load (VOC), varying the hydraulic holding time (HDT) of operation. For adherence of the microorganisms, the expanded clay was used as support material in the two reactors. The production of hydrogen and methane in the two phase system was identified, obtaining higher yield, yield and percentage in the hydrogen biogas in the TDH of 4 h, corresponding to the values of 0.33 L H2 (h L)-1, 2.40 mol H2(mol glucose)-1 and 32.85%. For production, yield and percentage of methane in biogas, higher values were observed in the TDH of 12 h. These values corresponded respectively to 0.00708 L CH4 (h L)-1, 0.0235 L CH4 gDQO-1 and 51.81%. During the reactor operation, acetic (12.2 - 7.9%), butyric (31.3 - 38.2%), isobutyric (2.5 - 1.9%), propionic (16.2 - 23%), caproic (1.3 - 1.2%) and valeric (1,7 - 1,1%), in addition to methanol (22 - 11.3%) and ethanol (12.8 - 15.2%). We conclude in general that the present work had a very interesting gain for both biogas production, as well as an environmental gain, since it is an industrial effluent treatment.