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Previous issue date: 2016-06-09 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Recentemente as microalgas e cianobact?rias vem sendo muito estudadas como fonte de biocombust?veis devido a sua elevada produtividade, elevado teor de ?leo e capacidade de crescer em uma grande variedade de climas e terras sem competir com a produ??o de alimentos. A pir?lise ? um m?todo de convers?o termoqu?mica eficaz capaz de converter biomassa em bio-?leo, carv?o e gases combust?veis. O bio-?leo ? uma mistura l?quida de compostos org?nicos potencial para substituir o ?leo diesel. Tem sido demosntrado que bio-?leos de microalgas e cianobact?rias s?o mais est?veis, apresentam teor de oxig?nio mais baixo e poder calor?fico mais alto que bio-?leos de biomassa lignocelul?sica, embora contenha um alto teor de nitrog?nio devido a presen?a de prote?nas na mat?ria-prima. A Spirulina ? uma cianobact?ria que vem sendo muito estudada nos processos de degrada??o t?rmica por apresentar alto teor de prote?nas (74%) e baixo teor de lip?dios (< 1%) podendo ser totalmente convertida em biocombust?vel. Nesta tese, foi investigado o potencial de produ??o de combust?veis e qu?micos a partir da pir?lise r?pida de Spirulina. Os experimentos de pir?lise r?pida convencional em Py-GC/MS foram conduzidos para investigar a influ?ncia dos par?metros de pir?lise, tais como temperatura, taxa de aquecimento e tempo de resid?ncia nos rendimentos dos produtos. O rendimento dos produtos da pir?lise foi maximizado a 450 ?C e 30 s, independente da taxa de aquecimento. Essas condi??es foram escolhidas para o estudo da pir?lise catal?tica com 9 ze?litas diferentes para avaliar a produ??o de hidrocarbonetos espec?ficos, compostos oxigenados e nitrogenados em func?o da raz?o biomassa/catalisador. O rendimento de hidrocarbonetos arom?ticos aumentou ? medida que a propor??o de catalisador/biomassa aumentou de 1:1 para 10:1. A ze?lita H-ZSM5 (23) apresentou o rendimento m?ximo de hidrocarbonetos e a maior redu??o de f?nois quando comparada as outras ze?litas, por?m os compostos nitrogenados totais n?o foram significativamente reduzidos por nenhum catalisador testado. Posteriormente testes de pir?lise r?pida de Spirulina foram conduzidos em um reator de leito fluidizado da USDA-ARS sob diferentes atmosferas de rea??o. Foram testadas a pir?lise convencional com atmosfera inerte (N2) e um processo de pir?lise com atmosfera reativa compostas por gases reciclados da pi?lise, denominado ?Tail Gas Reactive Pyrolysis? (TGRP). O bio-?leo, carv?o e gases produzidos pelo processo TGRP tiveram suas caracter?sticas melhoradas em rela??o aos produtos obtidos na pir?lise convencional, houve um aumento na concentra??o dos hidrocarbonetos arom?ticos e predominaram compostos nitrogenados com um ?nico ?tomo de nitrog?nio (piridinas, pirroles, indoles, nitrilas e amidas). Devido a esta composi??o, esse bio-?leo apresentou um n?vel suficientemente elevado de estabilidade t?rmica para ser destilado. Al?m disso, o bio-?leo produzido pelo processo TGRP foi mais est?vel, menos ?cido e apresentou um poder calor?fico mais alto que bio-?leos de biomassa lignocelul?sica. / Recently microalgae and cyanobacteria have been widely studied as a source of biofuels
due to its high yield, high oil content and ability to grow on a wide variety of climates and
land without competing with food production. Pyrolysis is an effective thermochemical
conversion method capable of converting biomass to fuels, including bio-oil, bio-char and
gas. Bio-oil is a liquid mixture of organic compounds that can be a source of valuable
chemicals and potential to replace diesel oil depending on its quality. It has been shown
that bio-oil from microalgae and other proteinaceous biomass are more stable, have a low
oxygen content and higher calorific value than those produced from lignocellulosic
feedstock, though contains high nitrogen content due to the presence of protein in its
constitution. Spirulina is a cyanobacteria that has been studied in the thermal degradation
processes due to its high protein and low lipids content. In this thesis, we investigated the
potential for production of fuels and chemicals from the fast pyrolysis of Spirulina.
Conventional fast pyrolysis experiments in Py-GC/MS were performed to investigate the
influence of pyrolysis parameters such as temperature, heating rate and residence time in
distribution of products. The pyrolysis yield was maximized at 450 ?C and 30 s, regardless
of heating rate. H-ZSM5 (23) showed the maximum hydrocarbon yield and the largest
phenols reduction when compared to the other zeolites, but the total nitrogenated
compounds were not significantly reduced by any catalyst tested although some specific
nitrogenous have been reduced or eliminated. H-? (38) was also able to increase aromatics
production, although its effect was less significant when compared to H-ZSM5 (23) and
(50). Subsequently tests of Spirulina fast pyrolysis were conducted in USDA?s bubbling
fluidized bed pyrolysis reactor under different reaction atmospheres. Conventional (N2
atmosphere) and reactive (Tail Gas Reactive Pyrolysis - TGRP) pyrolysis were tested. Biooil,
bio-char and gas obtained from TGRP process had their fuel characteristics improved
when compared to the products from conventional pyrolysis. TGRP Spirulina pyrolysis oil
showed an increased concentration of aromatics hydrocarbon and the presence of
nitrogenous compounds with single nitrogen atom (pyridines, pyrroles, indoles, nitriles and
amides), low oxygen content and low acidity being thermally stable therefore a good
feedstock for distillation process. Distillation successfully allowed concentrating various
chemicals into distillate fractions which, in turn, could be individually isolated for
processing to fuels or chemical co-products.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/21610 |
| Date | 09 June 2016 |
| Creators | Chagas, Bruna Maria Emerenciano das |
| Contributors | 04514998320, http://lattes.cnpq.br/5840621182000517, Boateng, Akwasi Acheampong, 00000000000, Oliveira, Jackson Ara?jo de, 65331060587, http://lattes.cnpq.br/5058617634570704, Pacheco Filho, Jos? Geraldo de Andrade, 32681089468, http://lattes.cnpq.br/6315186407922891, Braga, Renata Martins, 05165674460, http://lattes.cnpq.br/4603529162393328, Ata?de, Carlos Henrique, Melo, Marcus Antonio de Freitas |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM ENGENHARIA QU?MICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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