Geração de compostos químicos de interesse via pirólise lenta da microalga spirulina platensis

• Ano de defesa: 2021
• Autor(a) principal: Arruda, Ketley Costa Rocha
• Orientador(a): Ostroski, Indianara Conceição
• Banca de defesa: Ostroski, Indianara Conceição, Andrade, Laiane Alves de, Alonso, Christian Gonçalves, Borél, Lidja Dahiane Menezes Santos
• Tipo de documento: Dissertação
• 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 (RG)
• País: Brasil
• Palavras-chave em Português: Química fina; Bio-óleo; Otimização; Extração; Adsorção
• Palavras-chave em Inglês: Fine chemistry; Biooil; Optimization; Extraction; Adsorption
• Área do conhecimento CNPq: ENGENHARIAS::ENGENHARIA QUIMICA
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tede/11150

Investigations on the use of microalgae biomass, converted by pyrolysis, to replace fossil fuels have increased over the past decade. However, bio-oil contains oxygenated and nitrogenous compounds that prevent its direct application. Although prejudicial to biofuel, nitrogenous compounds could be separated and used for other applications, such as in the production of fine chemicals. Therefore, the potential of the highly proteinaceous biomass Spirulina platensis was evaluated to identify the optimum conditions for the production of high added-value nitrogenous compounds in liquid fraction via slow pyrolysis. Thus, in this work, the effects of operational conditions mass load, temperature, and heating rate on the liquid yield and the formation of nitrogenous compounds were evaluated using Experimental Design and Response Surface Methodology (RSM) techniques. An optimization study was performed through the use of Differential Evolution methodology (DE) to determine the operating conditions that maximize the liquid yield. After the pyrolysis process, extraction and adsorption routes were evaluated as potential processes for the separation of nitrogenous compounds. The experimental results indicated that bio-oil produced from slow pyrolysis of Spirulina platensis is a promising source for the generation of nitrogenous compounds, with a maximum of 90.64% of the compounds identified by gas chromatography – mass spectrometry (GC-MS) at mass conditions of 3.75 g, temperature 450 °C and heating rate of 1.7 ° C min-1. The results showed that operating conditions, especially the heating rate, significantly impacted both the liquid yield and the formation of these compounds. From the experimental test at optimal conditions (1.78 g, 556 °C and 10.48 °C m-1) a maximum liquid yield of 64.59% was obtained. The experimental values showed good agreement with the corresponding predicted values, with an error of less than 10%. The extraction with phosphoric acid showed to be a promising route to selectively separate the classes of compound, having remained cyclic compounds in the heavy phase and non-cyclic compounds in the light phase. While adsorption using activated carbon from coconut shell chemically treated with phosphoric acid (FAAC) was favorable in the selective separation of nitrogen compounds, especially the class of amides.