Synthesis of biodiesel from wastes of food industry via direct transesterification with methanol/carbon dioxide mixtures

Dissertation presented at Faculdade de Ciências e Tecnologia from Universidade Nova de Lisboa to obtain the degree of Master in Chemical and Biochemical Engineering

Utilização da tecnologia supercrítica no isolamento de ingredientes biofuncionais - aplicação ao caroço de azeitona e refugo de cereja

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Biotecnologia

Análise da atual unidade de desasfaltação pelo Propano para o tratamento de crudes não parafínicos

Este trabalho teve como principal objetivo o estudo da simulação da unidade de destilação atmosférica e a vácuo da fábrica de óleos base da Petrogal, permitindo verificar que, uma vez conseguido um modelo num programa de simulação que traduz o comportamento real de um dado processo, é possível sem riscos operacionais avaliar o efeito da alteração das condições normais de funcionamento desse processo. O trabalho foi orientado pelo Eng.º Carlos Reis, no que diz respeito à empresa, e pelo Prof. Dr. Luís Silva, pelo ISEP. O trabalho foi dividido em duas partes, sendo a primeira direcionada à obtenção do novo crude a partir de dois crudes pesados e caracterização dessa mistura. Já a segunda parte reside na refinação deste novo crude através da plataforma Aspen Plus para obtenção do resíduo de vácuo, para posterior processamento na coluna de discos rotativos usando um método de separação por extração liquido-liquido. Estudaram-se as propriedades físicas dos fluidos e verificou-se que na destilação atmosférica as curvas de destilação encontram-se muito próximas comparativamente com os resultados obtidos pela empresa, enquanto na destilação a vácuo os valores encontram-se mais afastados, apresentando uma variação de 30ºC a 100ºC em relação aos valores obtidos pelo Petro-Sim. Com a finalidade de cumprir um dos objetivos em falta, irão ser realizadas futuramente simulações no extrator de discos rotativos para otimização do processo para crudes pesados, sendo os resultados facultados, posteriormente, à Petrogal. Durante a realização do trabalho foi atingido um modelo real representativo da unidade de destilação atmosférica e a vácuo da Petrogal, podendo obter-se resultados para qualquer tipo de crude, fazendo apenas variar o assay da corrente de alimentação.

Analisador de dispersão de energia

Dissertação para obtenção do Grau de Mestre em Engenharia Física

Pressupostos teóricos e metodológicos para a extracção automática de unidades terminológicas multilexémicas

Tese de doutoramento em Linguística, especialidade de Lexicologia - Terminologia

Avaliação do potencial de atenuação natural do passivo ambiental das bacias de lamas oleosas da RESIM - Águas de St. André - Caso de estudo

As bacias de lamas oleosas do Ecoparque RESIM de Santo André constituem um passivo ambiental devido à contaminação dos seus solos. O presente trabalho consistiu no estudo de amostras de solo provenientes das bacias de lamas oleosas com o objectivo de avaliar o potencial de atenuação natural nas mesmas. As amostras foram caracterizadas para vários parâmetros físico-químicos como pH, potencial redox, condutividade eléctrica, aniões (através do método de cromatografia iónica), textura, teor de humidade e densidade e foram ainda determinados os compostos orgânicos voláteis e semi-voláteis das amostras de forma a conhecer a natureza da contaminação. A determinação dos compostos orgânicos voláteis foi realizada com os métodos Headspace - Cromatografia Gasosa - Espectrometria de massa. Os compostos semi-voláteis foram extraídos através do método Soxhlet Warm e determinados através de Cromatografia Gasosa - Espectrometria de Massa. Tanto a caracterização físico-química como a determinação dos compostos foram realizadas antes e após um ensaio de respirometria. Os ensaios de respirometria foram realizados em frascos OxiTop e conduzidos em ambiente controlado a uma temperatura média de 23,5 ºC durante alguns dias. Os contaminantes detetados foram essencialmente hidrocarbonetos aromáticos policíclicos (PAH), mais concretamente o naftaleno, compostos BTEX e uma vasta gama de hidrocarbonetos do petróleo. As amostras em estudo apresentaram variações nas abundâncias e natureza dos compostos presentes após os ensaios de respirometria. O método de respirometria utilizado não se mostrou apropriado para amostras com elevadas abundâncias de compostos orgânicos voláteis.

Automatic extraction of concepts from texts and applications

The extraction of relevant terms from texts is an extensively researched task in Text- Mining. Relevant terms have been applied in areas such as Information Retrieval or document clustering and classification. However, relevance has a rather fuzzy nature since the classification of some terms as relevant or not relevant is not consensual. For instance, while words such as "president" and "republic" are generally considered relevant by human evaluators, and words like "the" and "or" are not, terms such as "read" and "finish" gather no consensus about their semantic and informativeness. Concepts, on the other hand, have a less fuzzy nature. Therefore, instead of deciding on the relevance of a term during the extraction phase, as most extractors do, I propose to first extract, from texts, what I have called generic concepts (all concepts) and postpone the decision about relevance for downstream applications, accordingly to their needs. For instance, a keyword extractor may assume that the most relevant keywords are the most frequent concepts on the documents. Moreover, most statistical extractors are incapable of extracting single-word and multi-word expressions using the same methodology. These factors led to the development of the ConceptExtractor, a statistical and language-independent methodology which is explained in Part I of this thesis. In Part II, I will show that the automatic extraction of concepts has great applicability. For instance, for the extraction of keywords from documents, using the Tf-Idf metric only on concepts yields better results than using Tf-Idf without concepts, specially for multi-words. In addition, since concepts can be semantically related to other concepts, this allows us to build implicit document descriptors. These applications led to published work. Finally, I will present some work that, although not published yet, is briefly discussed in this document.

Valorization of olive pomace through combination of biocatalysis with supercritical fluid technology

A supercritical carbon dioxide (scCO2) based oil extraction method was implemented on olive pomace (alperujo), and an oil yield of 25,5 +/- 0,8% (goil/gdry residue) was obtained. By Soxhlet extraction with hexane, an oil extraction yield of 28,9 +/- 0,8 % was obtained, which corresponds to an efficiency of 88,4 +/- 4,8 % for the supercritical method. The scCO2 extraction process was optimized for operating conditions of 50 MPa and 348,15 K, for which an oil loading of 32,60 g oil/kg CO2 was calculated. As a proof of concept, olive pomace was used as feedstock for biodiesel production, in a process combining the use of lipase as a catalyst with the use of scCO2 as a solvent, and integrating the steps of oil extraction, oil to biodiesel transesterification and subsequent separation of the latter. In the conducted experiments, FAME (fatty acid methyl ester) purities of 90% were obtained, with the following operating parameters: an oil:methanol molar ratio of 1:24; a residence time of 7,33 and 11,6 mins; a pressure of 40 MPa; a temperature of 313,15 K; and Lipozyme (Mucor miehei; Sigma-Aldritch) as an enzyme. However, oscillations of FAME purity were registered throughout the experiments, which could possibly be due to methanol accumulation in the enzymatic reactor. Finally, the phenolic content of olive pomace, and the effect of the drying process – oven or freeze-drying – and the extraction methods – hydro-alcoholic method and supercritical method – on the phenolic content were analysed. It was verified that the oven-drying process on the olive pomace preserved 90,1 +/- 3,6 % of the total phenolic content. About 62,3 +/- 5,53% of the oven-dried pomace phenolic content was extracted using scCO2 at 60 MPa and 323,15 K. Seven individual phenols – hydroxytyrosol, tyrosol, oleuropein, quercetin, caffeic acid, ferulic acid and p-coumaric acid – were identified and quantified by HPLC.

Determinação prática do teor de óleo na polpa do abacate (Persea americana Miller) através da correlação com o teor de água

Como o processo atual utilizado para a determinação do teor de óleo na polpa do abacate (extrator de Soxhlet) é oneroso e muito demorado, torna-se importante o conhecimento de um método que possibilite de maneira prática e rápida a avaliação do teor de óleo na polpa. No presente trabalho procurou-se comprovar uma possível correlação entre os teores de água e óleo na polpa do abacate. A determinação da porcentagem de água na polpa é fácil e de baixo custo. Através dela poder-se-ia determinar o teor de óleo. Com esse objetivo conduziu-se um experimento em três regiões ecologicamente diferentes do Estado de São Paulo: Novo Horizonte, Limeira e Itapetininga. Em cada região, utilizou-se três pomares e em cada pomar selecionou-se cinco árvores das cultivares 'Wagner', 'Prince' e 'Collinson' colhendo-se dois frutos de cada árvore, que no conjunto (dez frutos) formaram a amostra a ser analisada, para cada cultivar. Efetuaram-se colheitas em épocas pré-determinadas, visando a análise do teor de óleo e de água na polpa do fruto, desde a sua formação até a época de maturação. Efetuou-se também análises em amostras de frutos deixadas amadurecer até o ponto de consumo (polpa mole). Foi observado que a evolução do teor de óleo na polpa do abacate se processa lentamente no início, acentuando-se no final do desenvolvimento do fruto e o inverso para o teor de água. Foi constatado uma correlação entre o aumento do teor de óleo e a diminuição do teor de água na polpa do abacate. Relacionando-se tal fato, encontrou-se uma equação geral de regressão Y = 86,626 -- 0,727 X, onde Y = porcentagem de água e X = porcentagem de óleo, com ótima adaptação à regressão linear, como comprovou o seu coeficiente de determinação de 91,50%.

Occurrence and bioaccumulation study of PCDD and PCDF from mineral feed additives

Occurrence of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) was evaluated in sepiolite as a widely employed binder and anti-caking agent for animal feed. Also, naturally contaminated kaolinitic clay was used for comparative purposes. Since sepiolite shows remarkable adsorption properties, particular interest was paid to the extraction steps as they become critical for the final determination of these pollutants in such matrixes. Furthermore, classical Soxhlet extraction using different extracting strategies as well as acid treatment were carried out with simultaneous liquid-liquid extraction. Results obtained depended on the extraction procedure applied. Acid treatment or Soxhlet extraction using a mixture of toluene:ethanol as solvent allowed to reach the minimum requirements of recovery rates. However, Soxhlet extraction using a mixture cyclohexane:toluene as extracting solvent did not allow to comply with minimum specifications for recovery. Significant differences were obtained in TEQ units when acid treatment was applied in comparison to Soxhlet extraction. This fact can be explained because the use of drastic acid conditions allows removing strongly adsorbed analytes which can be uniquely extracted after a total destruction of the crystalline structure of sepiolite. On the contrary, Soxhlet extraction was not able to destroy the structure of sepiolite and as a consequence the PCDDs/Fs were strongly adsorbed in the internal structure of the mineral. From biological point of view the availability of these toxicants constitutes a critical aspect playing an important role in the final decision choosing particular analytical procedures. Then, acid conditions in the digestive tract should be taken into account. In this scenario, a bioaccumulation study was conducted to evaluate the transference of PCDDs/PCDFs from the sepiolite into the animal tissues when fed with feed containing sepiolite. To this end, chickens were used as a model to examine the bioavailability of PCDDs/PCDFs. Four groups of chickens were exposed through their diet to a control feed, feed with 3% w/w sepiolite as additive, feed contaminated with PCDDs/PCDFs at concentration around 2.8 pg WHO-TEQ/g and feed with 2% of a contaminated kaolinitic clay (460 pg TEQ/g mineral). Livers of the four studied groups were analyzed throughout the exposure period. Results of this trial showed that the performance of broilers was not affected by the presence of dioxins at levels tested, and chickens did not show any abnormal behaviour. Dioxins intentionally added to the diet were absorbed and accumulated in the liver in a significant manner, whereas the PCDDs/Fs from sepiolite were not available for chickens since livers from broilers fed 3% sepiolite presented similar WHO-TEQ values than those from broilers fed control diet.

Nivells de radó en exterior i recintes tancats a la marjal càrstica de Peníscola

S’ha portat a terme un mostreig de diferents punts de la Marjal de Peníscola i 7 instal·lacions properes amb la finalitat de determinar les concentracions de 222Rn en aire exterior i interior. Les anàlisis en els punts exteriors obtenen unes concentracions de 222Rn elevades, superiors a 50 Bq·m-3 en alguns punts. El fet que el sòl de la marjal tingui altes concentracions de 226Ra i elevades concentracions de 226Ra i 222Rn en l’aigua salobre poden justificar aquests valors. L’alta activitat de l’aigua, les característiques de l’edifici i mala gestió del sistema de clavegueram de Peníscola són els responsables de les elevades concentracions de 222Rn en l’aire interior de la depuradora, amb concentracions màximes de més de 70000 Bq·m-3. Un sistema de ventilació adequat com un extractor de PVC evitaria l’acumulació del 222Rn a l’interior de la instal·lació.

Determinació d'hidrocarburs aromàtics policíclics (PAHs) en mostres de sòls per cromatografia de gasos acoblada a l'espectrometria de masses (GC/MS)

La importància dels Hidrocarburs Aromàtics Policíclics (PAHs) com a contaminants ha estat sempre en debat. Des del moment en què no compleixen els requeriments de persistència, toxicitat i transport a llargues distàncies, no es consideren contaminants orgànics persistents (POPs). En conseqüència, no es troben inclosos dins la llista dels dirty dozen de la Convenció d’Estocolm sobre POPs. A més, ja que el seu alliberament no és intencionat, algunes veus han plantejat la possibilitat d’eliminar o reduir la quantitat d’aquests compostos a l’atmosfera i que arriben també, per deposició, al sòl, sediments, aigües, etc. Tanmateix, segons el Protocol firmat pel Comitè Estats Units-Europa (UNECE), els PAHs haurien d’haver estat inclosos a aquesta llista ja que són productes químics les emissions dels quals haurien de ser minimitzades o previngudes. És per això i l’interès pel medi ambient que dins el projecte Estudi de la influència de contaminants orgànics (BTEX i PAHs) en la mobilitat de metalls pesants en sòls, al qual es vol entendre quin és el mecanisme de transport dels metalls pesants en presència d’aquests contaminants, enfocat sobretot als marges de les carreteres per la combustió de gasolines i l’exhaust dels vehicles, que es justifica aquest treball de recerca. Aquest treball de recerca es basa en la posta a punt d’un mètode d’anàlisi de PAHs mitjançant la Cromatografia de Gasos acoblada a l’Espectrometria de Masses (GC/MS). Cadascun dels mètodes seguits estan reportats a la Environmental Protection Agency dels Estats Units (US EPA), però tot i així cal fer la optimització, realitzant o no, lleus modificacions d’aquests per ajustar-nos a les nostres necessitats específiques. En aquest treball de recerca s’exposen els diferents passos a realitzar un cop feta la presa de mostra fins l’expressió final dels resultats un cop identificats i quantificats els PAHs d’interès presents en una matriu de sòl. Això comprèn la seva extracció inicial mitjançant el Soxhlet, un cleanup posterior a partir tant de l’extracció en fase sòlida (SPE) amb una fase C18 com la cromatografia en columna utilitzant gel de sílice com a adsorbent. Finalment, s’han determinat els paràmetres influents en la separació, identificació i quantificació dels PAHs amb relació a la cromatografia de gasos i la seva detecció per espectrometria de masses.

A new hybrid summarizer based on vector Space model, statistical physics and linguistics

In this article we present a hybrid approach for automatic summarization of Spanish medical texts. There are a lot of systems for automatic summarization using statistics or linguistics, but only a few of them combining both techniques. Our idea is that to reach a good summary we need to use linguistic aspects of texts, but as well we should benefit of the advantages of statistical techniques. We have integrated the Cortex (Vector Space Model) and Enertex (statistical physics) systems coupled with the Yate term extractor, and the Disicosum system (linguistics). We have compared these systems and afterwards we have integrated them in a hybrid approach. Finally, we have applied this hybrid system over a corpora of medical articles and we have evaluated their performances obtaining good results.

Boron extraction and vertical mobility in Paraná State oxisol, Brazil

The deficiency or excess of micronutrients has been determined by analyses of soil and plant tissue. In Brazil, the lack of studies that would define and standardize extraction and determination methods, as well as lack of correlation and calibration studies, makes it difficult to establish limits of concentration classes for analysis interpretation and fertilizer recommendations for crops. A specific extractor for soil analysis is sometimes chosen due to the ease of use in the laboratory and not in view of its efficiency in determining a bioavailable nutrient. The objectives of this study were to: (a) evaluate B concentrations in the soil as related to the fertilizer rate, soil depth and extractor; (b) verify the nutrient movement in the soil profile; (c) evaluate efficiency of Hot Water, Mehlich-1 and Mehlich-3 as available B extractors, using sunflower as test plant. The experimental design consisted of complete randomized blocks with four replications and treatments of five B rates (0, 2, 4, 6, and 8 kg ha-1) applied to the soil surface and evaluated at six depths (0-0.05, 0.05-0.10, 0.10-0.15, 0.15-0.20, 0.20-0.30, and 0.30-0.40 m). Boron concentrations in the soil extracted by Hot Water, Mehlich-1 and Mehlich-3 extractors increased linearly in relation to B rates at all depths evaluated, indicating B mobility in the profile. The extractors had different B extraction capacities, but were all efficient to evaluate bioavailability of the nutrient to sunflower. Mehlich-1 and Mehlich-3 can therefore be used to analyze B as well as Hot Water.

Potassium availability in a hapludalf soil under long term fertilization

In a system in which fertilization is recommended, diagnosis of soil K availability and the establishment of critical levels are made difficult by the possibility of a contribution of non-exchangeable forms of K for plant nutrition. Due to its magnitude, this contribution is well diagnosed in long term experiments and in those which compare fertilization systems with positive and negative balances in terms of replacement of the K extracted by plants. The objective of this study was to evaluate K availability in a Hapludalf under fertilization for sixteen years with the addition of K doses. The study was undertaken in an experiment set up in 1991 and carried out until 2007 in the experimental area of the Soil Department of the Federal University of Santa Maria (Universidade Federal de Santa Maria - UFSM), in Santa Maria (RS), Brazil. The soil was a Typic Hapludalf submitted to four doses of K (0, 60, 120 and 180 kg ha-1 K2O) and subdivided in the second year, when 60 kg ha-1 of K2O were reapplied in the subplots in 0, 1, 2 and 3 times. As of the fifth year, the procedure was repeated. Grain yield above ground dry matter and total K content contained in the plant tissue were evaluated. Soil samples were collected, oven dried, ground, passed through a sieve and submitted to exchangeable K analysis by the Mehlich-1 extractor; non-exchangeable K by boiling HNO3 1 mol L-1 and total K by HF digestion. Potassium fertilization guidelines should foresee the establishment of a critical level as of which the recommended dose should accompany crop needs, which coincides with the quantity exported by the grain, without there being the need for the creation of broad ranges of K availability to predict K fertilization. In adopting the K fertilization recommendations proposed in this manner, there will not be K translocation in the soil profile.