Produção de biogás integrada ao conceito de biorrefinaria para biomassa lignocelulósica: aspectos operacionais e uso de nanopartículas

Author(s)

Maria Paula Cardeal Volpi

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia de Alimentos
• Defense date: 2022-05-24

Examining board members

Bruna de Souza Moraes; Renata Piacentini Rodriguez; Lucas Tadeu Fuess; Ariovaldo José da Silva

• Advisor: Bruna de Souza Moraes; Flavia Vischi Winck

Abstract

Biogas production occurs through anaerobic digestion (AD), which allows the energetic recovery of the organic source through the use of methane (CH4). Substrates from the sugar-alcohol activity are considered as potential facilitators of the development of biorefineries, making the system more resilient and versatile. In this context, the co-digestion of substrates of different biodegradability (more degradable with less degradable) appears as an interesting alternative, being able to soften the inhibitory effects of those residues to AD, in addition to being able to improve the process of monodigestion of vinasse that is "conventionally " carried out in ethanol plants. Therefore, the objective of this work was to co-digest residues from the 1G ethanol-producing (vinasse and filter cake) and residues from the 2G ethanol-producing (deacetylation liquor) to obtain biogas and propose the integration of the 1G2G biorefinery. Stage 1 of the project consisted of performing the Biochemical Methane Potential (BMP) analysis of each residue, stage 2 was the operation in a continuous reactor for the co-digestion of three residues, and stage 3 was an optimization of biogas production with adding Fe3O4 nanoparticles (NP) in the co-digestion reactor operation (the same was operated in stage 2). For stages 2 and 3 was done identification of the microbial consortium together with extracellular proteins (proteome analysis), to trace the metabolic route in both reactor operations. BMP results showed that co-digestion of vinasse 1G with filter cake and deacetylation liquor improved the CH4 yield of isolated substrates, reaching 605 NmLCH4 gVS-1. Vinasse and deacetylation liquor as the only co-substrates increased PBM by 38% over vinasse, indicating nutritional synergism. In the continuous operation of the co-digestion reactor of the three residues, the highest CH4 yield was 230 NmLCH4 gSV-1 with average organic matter removal efficiency of 83% + 13 achieved at Organic Load Rate (OLR) of 4.16 gVS L-1day-1. Furthermore, the use of Fe3O4 NP proved to be efficient in the process of optimizing the production of CH4, since the maximum value was were 2.8 ± 0.1 NLCH4 gVS-1 being 90% higher than that obtained in the co-digestion without the presence of NP. The main methanogenic Archaea found in both reactors (stage 2 and stage 3) was Methanoculleus, indicating that the predominant metabolic route possible was syntrophic acetate oxidation (SAO) coupled with hydrogenotrophic methanogenesis. Through these results, was possible to perform an energy analysis and obtained the installed capacity for an integrated 1G2G ethanol biorefinery of more than 50 MW (considering only the energy capacity of biogas) during the season period. By converting biogas into biomethane, the need for biofuel in the fleet of the largest ethanol plant in Brazil was provided and still obtained a surplus that can be injected into the gas grid and generate electricity. In general, the results obtained showed that the co-digestion of the proposed residues is a viable alternative for the production of biogas and integration of the 1G2G ethanol biorefinery (AU)

• FAPESP's process: 18/09893-1 - Biogas production integrated to the concept of lignocellulosic biomass: operational aspects and use of nanoparticles
• Grantee: Maria Paula Cardeal Volpi
• Support Opportunities: Scholarships in Brazil - Doctorate