Gaseificação catalítica de efluente da indústria de biodiesel para a produção de hidrogênio

• Ano de defesa: 2023
• Autor(a) principal: Mourão, Lucas Clementino
• Orientador(a): Alonso, Christian Gonçalves
• Banca de defesa: Alonso, Christian Gonçalves, Corazza, Marcos Lúcio, Chagas, Rafael Pavão das, Colmati Júnior, Flávio, Alves, Helton José
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Programa de Pós-graduação em Química (IQ)
• Departamento: Instituto de Química - IQ (RMG)
• País: Brasil
• Palavras-chave em Português: Hidrogênio; Água supercrítica; Catalisador estruturado; Glicerol; Biomassa residual
• Palavras-chave em Inglês: Hydrogen; Supercritical water; Structured catalyst; Glycerol; Residual biomass
• Área do conhecimento CNPq: CIENCIAS EXATAS E DA TERRA::QUIMICA::FISICO-QUIMICA
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tede/12870

The increasing global pollution, combined with a growing demand for energy, is driving the search for environmentally-friendly alternatives in energy production. Hydrogen, which has emerged as an important energy vector, is primarily produced from non-renewable sources such as petroleum. The development of innovative technologies has facilitated the utilization of renewable sources for hydrogen production, such as Supercritical Water Gasification (ScWG) of biomass. Among the potential feedstocks for hydrogen production, glycerol, a byproduct of the biodiesel industry, stands out as a promising candidate for ScWG. Due to the increasing production of biodiesel, a large supply of glycerol is being produced without a corresponding increase in demand. As a result, the biodiesel production chain has garnered increased interest from several research initiatives aimed at valorizing waste materials into higher value-added products. Combined with heterogeneous catalysis, the ScWG process can increase selectivity towards products of interest and achieve high conversion efficiency of organic matter, even with short residence times. In this work, the catalytic gasification of glycerol and real wastewater from a biodiesel industry were evaluated. Ni based catalyst were synthetized by simple and fast wet impregnation method of metallic nitrates supported on a honeycomb cordierite (CRD) structure. The catalysts were characterized by SEM-EDS, XRD, N2 adsorption/desorption, XRF, WDS and TGA. The performance of the Ni-based catalyst was evaluated in the ScWG of glycerol and compared to two commercial Automotive Catalysts (ACs). The ScWG of glycerol was carried out under different conditions in order to establish optimal operating parameters. The tests were conducted at reactor temperatures ranging from 400ºC to 700ºC, a system pressure of 25 MPa, and glycerol mass concentrations ranging from 10% to 34%. For optimal conditions (600 ºC and glycerol 10wt%), the results indicated that Ni/CRD catalyst showed the highest H2 yield (1,40 mol/mol C) and carbon conversion (95%). Although they have shown efficiency in the gasification of glycerol, the ACs showed higher tendencies for activity loss in carbon conversion compared to Ni based catalys over time (300 min). Preliminary tests using real industrial effluent (BIOD) were conducted, evaluating parameters of temperature (400 - 600°C), feed flow rate (10 - 20 mL/min), and effluent concentration based on total organic carbon (TOC) (50 - 100%). The results showed that temperature had the greatest influence on gasification, with a carbon conversion of 77% and an H2 yield of 2.85 mol/mol C at 600°C (10 mL/min; 50% TOC). Catalytic test conducted under the best condition (600 ºC; 10 mL/min; 100% TOC) showed higher carbon conversion, while non-catalytic test obtained higher H2 selectivity (76%). The results showed that structured catalyst has great potential to enhance the production of H2-rich gas specially from glycerol GASc. The use of biodiesel residue as a raw material for the ScWG process is promising since it allows the treatment of the residue and the production of H2-rich gas simultaneously.