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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Fermenta??o alco?lica utilizando l?quido da casca de coco verde como fonte de nutrientes / Fermenta??o alco?lica utilizando l?quido da casca de coco verde como fonte de nutrientes

Teixeira, Renata Beltr?o 15 June 2007 (has links)
Made available in DSpace on 2014-12-17T15:01:12Z (GMT). No. of bitstreams: 1 RenataBT.pdf: 1220401 bytes, checksum: a52c88053d4d3cde9e007821b799d056 (MD5) Previous issue date: 2007-06-15 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The liquid of the rind of green coconut (LCCV), an effluent stream from the industrial processing of green coconut rind, is rich in sugars and is a suitable feedstock for fermentation. The first step of this study was to evaluate the potential of natural fermentation of LCCV. As the literature did not provide any information about LCCV and due to the difficulty of working with such an organic effluent, the second step was to characterize the LCCV and to develop a synthetic medium to explore its potential as a bioprocess diluent. The third step was to evaluate the influence of initial condensed and hydrolysable tannins on alcoholic fermentation. The last step of this work was divided into several stages: in particular to evaluate (1) the influence of the inoculum, temperature and agitation on the fermentation process, (2) the carbon source and the use of LCCV as diluent, (3) the differences between natural and synthetic fermentation of LCCV, in order to determine the best process conditions. Characterization of LCCV included analyses of the physico-chemical properties as well as the content of DQO, DBO and series of solids. Fermentation was carried out in bench-scale bioreactors using Saccharomyces cerevisiae as inoculum, at a working volume of 5L and using 0.30% of soy oil as antifoam. During fermentations, the effects of different initial sugars concentrations (10 - 20%), yeast concentrations (5 and 7.5%), temperatures (30 - 50?C) and agitation rates (400 and 500 rpm) on pH/sugars profiles and ethanol production were evaluated. The characterization of LCCV demonstrated the complexity and variability of the liquid. The best conditions for ethanol conversion were (1) media containing 15% of sugar; (2) 7.5% yeast inoculum; (3) temperature set point of 40?C and (4) an agitation rate of 500 rpm, which resulted in an ethanol conversion rate of 98% after 6 hours of process. A statistical comparison of results from natural and synthetic fermentation of LCCV showed that both processes are similar / A utiliza??o do l?quido da casca de coco verde (LCCV) em fermenta??o surgiu como uma alternativa ao aproveitamento de um efluente, rico em a??cares ferment?veis, liberado pelas usinas de beneficiamento da casca de coco verde. A primeira fase deste trabalho foi avaliar o potencial fermentativo do l?quido da casca de coco verde atrav?s da fermenta??o natural do l?quido. Por n?o possuir informa??o dispon?vel na literatura e pela dificuldade de se trabalhar com um efluente org?nico, a segunda fase foi realizar a caracteriza??o do l?quido e a elabora??o de um meio sint?tico, para melhor explorar seu potencial como diluente em bioprocessos. A terceira fase, estudar a influ?ncia de taninos iniciais condensados e hidrolis?veis em fermenta??o alco?lica. A ?ltima fase foi dividida em tr?s etapas, na qual se avaliou a influ?ncia da quantidade de in?culo no processo fermentativo; a influ?ncia da fonte de carbono e do uso de LCCV como diluente; a temperatura; a agita??o e, finalmente, o estudo comparativo entre o LCCV in natura e sint?tico, nas condi??es ?timas de processo. Para a caracteriza??o foram realizadas an?lises f?sico-qu?micas do LCCV, bem como os teores de DQO, DBO e s?rie de s?lidos. As fermenta??es foram realizadas em biorreator de bancada, com volume de trabalho de 5L, Saccharomyces cerevisiae e 0,30% de ?leo de soja como antiespumante. Nas fermenta??es foram avaliadas diferentes concentra??es de a??cares iniciais (10 a 20%) e de levedura (5 e 7,5%), e diferentes temperaturas (30 a 50?C) e agita??es (400 e 500rpm). Durante o processo foram analisados o perfil de pH e de a??cares, e a produ??o de etanol. A caracteriza??o do LCCV demonstrou a complexidade e variabilidade do l?quido. As melhores condi??es foram alcan?adas nos meios contendo 7,5% de levedura, 15% de a??cares, 40?C, sob agita??o de 500rpm, sendo obtida uma efici?ncia de convers?o em etanol de 98% ap?s 6 horas de processo. Durante o estudo comparativo do LCCV in natura e sint?tico, atrav?s dos par?metros avaliados durante a fermenta??o, um estudo estat?stico revelou a similaridade do meio sint?tico com o meio natural
2

Tratamento BiolÃgico do LÃquido da Casca do Coco Verde / Coconut Husk Liquor treatment Biological

MÃrio de Alencar Freitas Neto 26 July 2007 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / With the aim of aggregating value to the productive chain of coconut and to expand its agrobusiness, Embrapa AgroindÃstria Tropical (Brazilian Agricultural Research Corporation, Tropical Agroindustry National Centre) developed a system for processing the husk of immature coconut in order to produce fibre and coir dust, which have several environmental and commercial applications. During the pressing stage, a liquid is generated, denominated Coconut Husk Liquor (CHL), which contains high concentration of organic matter (varying form 60 to 80 gDQO/L), including tannins. In this work, the performance of an Upflow Anaerobic Sludge Blanket Reactor (UASB) and a Fungi Biological Reactor (FBR) were evaluated for the treatment of CHL. The lab-scale UASB reactor, with a working volume of 16,8L, was operated during 222 days with an increasing organic loading rate (OLR), starting from 2.2 kgCOD/m3.d and reaching up to 10 kgCOD/m3.d. The lab-scale FBR, with a working volume of 100L, was operated with OLR of 5,0 kgCOD/m3.d, during 116 days, and then with OLR of 2,5 kgCOD/m3.d during 158 days. The performance of UASB reactor evaluated based on influent and effluent COD and total tannins; sludge specific methanogenic activity (SMA) and anaerobic toxicity; gas production and composition; pH, alkalinity and volatile fatty acids; and sludge retention time. The performance of FBR was monitored on the basis of on influent and effluent COD, total tannins and suspended solids. Other analysis were also accomplished: aerobic CHL biodegradability, sludge stability, and effect of Aspergillus niger on the degradation of CHL. Results showed that UASB reactor was maintained stable during the whole operation, with COD removal efficiency higher than 80%, total tannins removal efficiency of around 48%, and the ratio AGV/alkalinity lower than 0,30. Biogas presented 75% of methane on its composition. Toxicity tests demonstrated that CHL was not toxic to the methanogenic consortia. FBR was initially inoculated with Aspergillus niger AN-400. However, this fungus was substituted by the yeast that is natural on coconut husk, which was confirmed by tests carried out on Petri plate tests. When this reactor was operated with OLR of 5.0 kgCOD/m3.d and without sludge removal, the COD removal efficiency was around 58%. The performance improved up to 91% when OLR was decreased to 2.5 kgCOD/m3.d and sludge was weekly removed from the top or reactor. During this period, total tannin removal efficiency was approximately 15%. Despite the low tannin removal efficiency, this aerobic reactors can be used as an alternative for easy-degradable organic matter, facilitating the recovering of tannins for commercial uses. Results obtained from Petri plate tests show that Aspergillus niger AN-400 was able to grow in a medium with CHL. However, results from batch tests demonstrated that this species did not affect the DQO and tannins removal rates, when it is inoculated in a solution with raw CHL. The configuration of the reactor with fungi used in this research showed operational problems related with excess biomass removal. / Buscando agregar valor à cadeia produtiva do coco e expandir o agronegÃcio envolvido, a Embrapa AgroindÃstria Tropical desenvolveu um sistema de beneficiamento da casca do coco verde para produÃÃo de pà e fibra que tem diversas aplicaÃÃes ambientais e comerciais. Durante a etapa de prensagem do beneficiamento deste resÃduo, à gerado um lÃquido denominado LÃquido da Casca do Coco Verde (LCCV), que apresenta elevada concentraÃÃo de matÃria orgÃnica, cuja DQO varia de 60 a 80 gO2/L, incluindo taninos. Nesta Tese avaliou-se a performance de um reator anaerÃbio de fluxo ascendente e manta de lodo (Upflow Anaerobic Sludge Blanket â UASB) e um Reator BiolÃgico com Fungos (RBF) para tratamento do LCCV. O UASB escala de bancada (16,8L) foi operado durante 222 dias, com carga orgÃnica volumÃtrica (COV) crescente, iniciando com 2,2 KgDQO/mÂ.d, e finalizando com 10,0 KgDQO/mÂ.d. O RBF escala de bancada (100L) foi operado com COV de 5,0 KgDQO/mÂ.d durante 116 dias, e em seguida com COV de 2,5 KgDQO/mÂ.d durante 158 dias. A performance do UASB foi avaliada atravÃs de determinaÃÃes de DQO e taninos totais do afluente e efluente; atividade metanogÃnica especÃfica (AME) do lodo e toxicidade anaerÃbia; composiÃÃo e produÃÃo de biogÃs; pH, alcalinidade e Ãcidos graxos volÃteis (AGV). A performance do RBF foi monitorada atravÃs de determinaÃÃes de DQO, taninos totais e sÃrie de sÃlidos do afluente e efluente. AlÃm disso, foram realizados alguns ensaios: Biodegradabilidade aerÃbia do LCCV, estabilidade anaerÃbia do lodo, e o efeito da espÃcie Aspergillus niger AN 400 na degradaÃÃo do LCCV. Os resultados demonstraram que o UASB manteve-se estÃvel durante a operaÃÃo, com eficiÃncia de remoÃÃo de DQO superior a 80% e de taninos em torno de 48%. A razÃo AGV/alcalinidade ficou sempre inferior a 0,30. O biogÃs apresentou composiÃÃo de 75% de metano. Os ensaios de toxicidade demonstraram que o LCCV nÃo foi tÃxico à biomassa metanogÃnica presente no UASB. O RBF foi inicialmente inoculado com Aspergillus niger AN 400. No entanto, atravÃs de anÃlises microbiolÃgicas, foi comprovado que este fungo foi substituÃdo por leveduras naturalmente presentes no LCCV. Quando este reator foi operado com COV de 5,0 KgDQO/mÂ.d, e sem descarte de biomassa, a eficiÃncia de remoÃÃo de DQO ficou em torno de 58%. Esta eficiÃncia aumentou para 91% quando a COV aplicada diminuiu para 2,5 KgDQO/mÂ.d, e foram realizados descartes semanais da biomassa localizada na parte superior do reator. Neste perÃodo, a remoÃÃo mÃdia de taninos foi de 15%. Apesar desta baixa remoÃÃo de taninos, reatores aerÃbios podem ser usados como alternativas para remoÃÃo de matÃria orgÃnica facilmente degradÃvel, viabilizando a recuperaÃÃo dos taninos para uso comercial. Os resultados obtidos em testes em placas de Petri demonstraram que a espÃcie fÃngica Aspergillus Niger AN 400 foi capaz de se desenvolver em meio contendo LCCV. Contudo, resultados dos testes em batelada demonstraram que esta espÃcie nÃo alterou as taxas de remoÃÃo de DQO e taninos, quando foi inoculado em meio contendo LCCV bruto. A configuraÃÃo do reator com fungos utilizada nesta pesquisa apresentou problemas operacionais relacionados com o descarte do excesso de biomassa.
3

Estudo teÃrico-experimental de uma caldeira de queimador poroso recÃproco aplicado ao biogÃs / Theoretical and experimental study of reciprocal porous burner applied to biogas

LuÃs Carlos Eduardo Oliveira de Souza 27 March 2009 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / A DissertaÃÃo deMestrado trata do desenvolvimento de uma caldeira de vapor nÃo-convencional, onde à empregada a âCombustÃo de FiltraÃÃoâ. O objetivo da pesquisa foi estudar a combustÃo do BiogÃs do lÃquido da casca do coco verde, com respeito à eficiÃncia e emissÃes. A combustÃo à analisada com um modelo numÃrico, estruturado em FORTRAN e PREMIX, adaptado para processos de âCombustÃo em Meios Porososâ. Os resultados de simulaÃÃo sÃo confrontados com dados experimentais, que ressaltam vantagens operacionais em relaÃÃo Ãs caldeiras convencionais, destacando-se elevada eficiÃncia de extraÃÃo de energia e baixos nÃveis de emissÃes de CO e NOx. / The current Dissertation treats the theoretical and experimental studies about a non- conventional saturated steam boiler, in which a com bustion technology is employed, the âFiltration Combustionâ, as basis for conception of its burner construction design. This combustion thermal system was studied by means of a prototype, in laboratory scale, specially developed for this research. It was prop erly instrumented in order to make it possible to monitor as well as the combustion proce ss as the energy extraction in the reaction zone. The objective of this investigation is to verify the effects of the Biogas obtained from the anaerobic digestion of the Green Coconut Skin Liquid (GCSL), on the boiler operation, concerning efficiency and polluta nt emissions, as well as the reaction stability. Biogas combustion is analyzed by numeri cal model simulations, which take in account the mass, energy (gas and solid phases) and species conservation equations. The model is structured with a flexible code in languag e FORTRAN, which includes equilibrium calculation performed through premixed combustion simulation software, the PREMIX, adapted to the combustion process and heat transfer in porous medium. The simulation allows the prediction of the temperature distribution profiles along the burner and the combustion products as function of two main operation parameters, the equivalence ratio and the air-fuel mixture flow vel ocity. Simulation results are compared with measurements in this analysis and some design aspects of the "Porous Burner Boilerâ are discussed, which evidences its operational adva ntages in comparison to the conventional boilers, especially the high energy ex traction efficiency and low carbon and nitrogen oxides emission levels
4

Tratamento AnaerÃbio do LÃquido da Casca de Coco Verde / Anaerobic treatment of Coconut Husk Liquor (CHL)utilizing UASB reactor.

Alex Miranda de AraÃjo 21 February 2008 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Para promover o reuso de resÃduos da agroindÃstria e agregar valor à cadeia produtiva do coco verde, a Embrapa agroindÃstria tropical desenvolveu uma tecnologia capaz de aproveitar cascas deste produto. Atualmente, as cascas do coco verde compÃem a maior parte dos resÃduos sÃlidos depositados nas praias. A tecnologia converte as cascas em pà e fibra que possuem grandes aplicaÃÃes comerciais e ambientais. Durante a etapa de prensagem, ocorre a geraÃÃo do LÃquido da Casca de Coco Verde (LCCV), que apresenta elevada concentraÃÃo de matÃria orgÃnica, cuja Demanda QuÃmica de OxigÃnio (DQO) varia de 60 a 80 gO2/L, incluindo compostos fenÃlicos e aÃucares. Neste trabalho, avaliou-se a performance de um reator anaerÃbio de fluxo ascendente e manta de lodo (Upflow Anaerobic Sludge Blanket â UASB) para tratamento do LCCV. O reator UASB em escala de laboratÃrio (16,8 L) foi operado por 222 dias tendo sua carga orgÃnica volumÃtrica (COV) aumentada gradativamente de 2,2 atà 10 Kg DQO/ m3 d. A performance do UASB foi avaliada atravÃs de determinaÃÃes de DQO, compostos fenÃlicos totais (taninos) do afluente e efluente; atividade metanogÃnica especÃfica (AME) e toxicidade anaerÃbia do lodo; composiÃÃo e produÃÃo de biogÃs; pH, alcalinidade e Ãcidos graxos volÃteis (AGV). Os resultados demonstraram que o UASB pode ser usado para prÃ-tratamento do LCCV, mantendo-se estÃvel durante toda a operaÃÃo do sistema com remoÃÃo de DQO superior a 80% e de taninos em torno de 48%. A razÃo AGV/alcalinidade bicarbonato ficou sempre inferior a 0,40. O biogÃs apresentou composiÃÃo de 75% de metano. Os ensaios de toxicidade demonstraram que o LCCV nÃo foi tÃxico à biomassa metanogÃnica presente no UASB. / With the aim of reusing the agroindustry waste and aggregating value to the productive chain of immature coconut, Embrapa AgroindÃstria Tropical (Brazilian Agricultural Research Corporation, Tropical Agroindustry National Centre) has developed a system for processing this raw material. During the pressing stage, the Coconut Husk Liquor (CHL) is generated. It contains high concentration of organic matter, with Chemical Oxygen Demand (COD) varying from 60 to 80 g/L, including phenolic compounds and sugars. In this work, the performance of an Upflow Anaerobic Sludge Blanket Reactor (UASB) was evaluated for CHL treatment. The lab-scale UASB reactor (16.8 L) was operated during 222 days increasing the organic loading rate (OLR) from 2.2 kgCOD/m3.d to 10 kgCOD/m3.d. The UASB reactor performance was evaluated based on influent and effluent COD and total phenolic compounds (tannin); sludge specific methanogenic activity (SMA) and anaerobic toxicity; biogas production and composition; pH, alkalinity and volatile fatty acids (VFA). Results showed that UASB reactor can be used for pre-treatment of CHL, showing stability during the operation period, with COD removal efficiency higher than 80%, phenolics compounds removal efficiency of around 48%. The ratio AGV/alkalinity was always lower than 0,30. Biogas presented 75% of methane on its composition. Toxicity tests demonstrated that CHL was not toxic to the methanogenic consortia.

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