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Master's Dissertation
DOI
https://doi.org/10.11606/D.18.2021.tde-04102021-165214
Document
Author
Full name
Andrêza Borba da Silva
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 2021
Supervisor
Committee
Silva, Edson Luiz (President)
Garcia, Marcelo Loureiro
Kwong, Wu Hong
Title in Portuguese
Efeito de temperaturas termofílica e hipertermofílica na produção de hidrogênio e 1,3-propanodiol a partir de vinhaça de cana-de-açúcar e glicerol bruto como cossubstratos em reatores anaeróbios de leito fluidificado
Keywords in Portuguese
Biocombustível
Biohidrogênio
Digestão anaeróbia
Metabólitos solúveis
Abstract in Portuguese
A produção de H2 e intermediários químicos por processos fermentativos é uma linha de pesquisa atual e pode representar uma alternativa para o setor sucroenergético e para a indústria de biodiesel, possibilitando melhorias na eficiência produtiva e energética dos processos. Nesse sentido, o objetivo principal deste trabalho foi investigar a produção de H2 e 1,3-Propanodiol (1,3-PDO) pela estratégia de codigestão de vinhaça de cana-de-açúcar e glicerol, em reatores anaeróbios de leito fluidificado (RALF), sob condições termofílicas e hipertermofílicas (55, 60 e 65°C). Neste estudo, foram utilizados três reatores, com concentração afluente fixa (10 g DQO.L-1), contudo com proporções previamente estabelecidas para cada reator (RALF 1: 75% DQO vinhaça + 25% DQO glicerol; RALF 2: 50% DQO vinhaça + 50% DQO glicerol; RALF 3: 25% DQO vinhaça + 75% DQO glicerol). As fases de operação dos reatores foram estabelecidas em função do aumento da temperatura na faixa termofílica e hipertermofílica (55, 60 e 65°C). Os maiores valores de produção volumétrica de H2 (PVH) registrados no presente trabalho foram obtidos no RALF 1 (75% DQO vinhaça + 25% DQO glicerol), com PVH máxima de 2,92 ± 0,45 L.h-1 L-1 e rendimento de H2 (HY) de 0,74 mmol H2 g DQOadicionada-1. Os valores máximos relacionados a PVH foram obtidos nas temperaturas de 55°C para os RALFs 1 e 2. No RALF 3 a PVH máxima e o HY foram registrados na temperatura de 60°C. É pertinente sugerir que durante a 3ª fase (65°C) dos RALFs 1, 2 e 3 ocorreu síntese de células, visto que em maiores temperaturas o crescimento celular líquido é menor e a produção celular necessita compensar essa perda. O mesmo foi observado na 2ª fase (60°C) do RALF 2. A elevada temperatura pode ter causado alterações no metabolismo dos microrganismos, implicando prejuízo a PVH. Quanto à produção de 1,3 propanodiol (PV 1,3-PDO), os maiores valores foram observados no RALF 2 (50% DQO vinhaça + 50% DQO glicerol), com PV 1,3-PDO de 0,41 ± 0,11 g.L-1 h-1 e rendimento de 1,3-PDO (1,3-PDOY) de 0,89 ± 0,26 mol 1,3 PDO.mol-1 glicerol consumido. Notou-se que a temperatura de 65°C não implicou prejuízo na produção de 1,3-PDO, no RALF 2, visto que os valores de PV 1,3-PDO e 1,3-PDOY mantiveram-se estáveis. Contudo, foi observado decréscimo nos valores de PV 1,3-PDO e 1,3-PDOY nos RALFs 1 e 3, durante a 3ª fase experimental (65°C), indicando que, assim como na produção de H2, o aumento da temperatura exerceu influência negativa na produção de 1,3-PDO.
Title in English
Effect of thermophilic and hyperthermophilic temperatures on hydrogen and 1,3-propanodiol production from sugarcane vinasse and raw glycerol as co-substrates in anaerobic fluidized bed reactors
Keywords in English
Anaerobic digestion
Biofuel
Biohydrogen
Soluble metabolites
Abstract in English
The production of H2 and chemical intermediates by fermentative processes is a current research line and may represent an alternative for the sugar-energy sector and for the biodiesel industry, enabling improvements in the production and energy efficiency of the processes. In this sense, the main objective of this work was to investigate the production of H2 and 1,3-Proponodiol (1,3-PDO) by the codigestion strategy of sugarcane and glycerol vinasse, in anaerobic fluidized bed reactors (RALF), under thermophilic and hyperthermophilic conditions (55, 60 and 65°C). In this study, three reactors were used, with fixed affluent concentration (10 g COD.L-1), however with proportions previously established for each reactor (RALF 1: 75% COD vinasse + 25% COD glycerol; RALF 2: 50% COD vinasse + 50% COD glycerol; RALF 3: 25% COD vinasse + 75% COD glycerol). The operating phases of the reactors were established due to the increase in temperature in the thermophilic and hyperthermophilic range (55, 60 and 65°C). The highest values of volumetric production of H2 (HPR) recorded in the present work were obtained in RALF 1 (75% COD vinasse + 25% COD glycerol), with maximum HPR of 2.92 ± 0.45 Lh-1 L-1 and H2 yield (HY) of 0.74 mmol H2 g added DQO-1. The maximum values related to HPR were obtained at temperatures of 55°C for RALFs 1 and 2. In RALF 3 the maximum HPR and HY were recorded at a temperature of 60°C. It is pertinent to suggest that during the 3rd phase (65°C) of RALFs 1, 2 and 3, cell synthesis occurred, since at higher temperatures the liquid cell growth is lower and cell production needs to compensate for this loss. The same was observed in the 2nd phase (60°C) of RALF 2. The high temperature may have caused changes in the metabolism of microorganisms, causing damage to HPR. As for the production of 1.3 propanediol (PV 1.3-PDO), the highest values were observed in RALF 2 (50% COD vinasse + 50% COD glycerol), with PV 1.3-PDO 0.41 ± 0 , 11 g L-1 h-1 and yield of 1,3-PDO (1,3-PDOY) of 0.89 ± 0.26 mol 1.3 PDO.mol-1 glycerol consumed. It was noted that the temperature of 65°C did not affect the production of 1,3-PDO, in RALF 2, since the PV values 1,3-PDO and 1,3-PDOY remained stable. However, a decrease in the values of PV 1,3-PDO and 1,3-PDOY was observed in RALFs 1 and 3, during the 3rd experimental phase (65°C), indicating that, as in the production of H2, the increase temperature had a negative influence on the production of 1,3-PDO.
 
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Publishing Date
2021-10-15
 
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