Emissões gasosas durante a co-combustão de carvão com resíduos

Dissertação para a obtenção do Grau de Doutor em Engenharia Química especialidade Engenharia de Reacção QuímicaA biomassa e os resíduos não tóxicos poderão desempenhar um papel importante no âmbito do programa comunitário para encorajar o uso de energias renováveis. No entanto, a experiência mostra que a disponibilidade destes materiais poderá ser um sério obstáculo para uma utilização energética em grande escala. Deste modo, poderão ser utilizados como combustíveis auxiliares para a co-combustão em instalações a carvão. A sua utilização para produção de energia é prometedora, desde que se integrem bem com os outros combustíveis durante o processo de conversão energética e que não apresentem efeitos negativos no ambiente. Portanto, é imperativo que exista uma sinergia positiva entre o carvão e a biomassa, ou os resíduos, para que o impacte da co-combustão dos vários materiais minimize qualquer característica negativa de um combustível isolado. O presente estudo visou a determinação das condições de operação que poderiam trazer efeitos benéficos na eliminação dos resíduos e na utilização de biomassa para geração de energia, de uma forma ambientalmente aceitável, utilizando a tecnologia de leito fluidizado. Os sistemas de combustão em leito fluidizado são particularmente apropriados para a cocombustão devido à sua versatilidade quanto ao combustível utilizado. Este trabalho tinha como objectivo a determinação das condições de sinergia para minimização das emissões de alguns dos principais poluentes gasosos, nomeadamente CO, NOX, N2O, SO2, HCl e mercúrio. Foram cinco os resíduos estudados passando por um combustível derivado de resíduos sólidos urbanos (daqui em diante designado por CDR) por um resíduo resultante dos desperdícios da linhas de triagem da recolha selectiva de papel e de plástico (designado por RPP), por duas lamas pré-secas e granuladas resultante de dois lotes diferentes de um processo de tratamento de águas residuais urbanas (designadas por BG1 e BG2) e por um resíduo resultante da actividade de serração de madeira de pinho habitualmente chamado serrim pelo que se adoptou a designação de SR. O princípio de escolha residiu na disponibilidade de quantidades de resíduos existentes no departamento no âmbito de contratos comunitários e pela importância relativa crescente que este tipo de resíduos assume, hoje em dia, no desenvolvimento urbano e na qualidade de vida das populações (CDR e LRU). A utilização de SR prendeu-se mais com a preocupação de utilizar um recurso endógeno que constitui uma das riquezas do país – a floresta – de modo a reduzir a nossa dependência externa em termos energéticos. O estudo envolveu um levantamento de quantidades de resíduos existentes, a preparação adequada do combustível para alimentação, e a avaliação do seu desempenho durante a combustão. Actualmente, devido às alterações climáticas atribuídas em grande parte à libertação de gases de efeito de estufa, uma questão de grande preocupação é a emissão de grandes quantidades de CO2 para a atmosfera pelas centrais termoeléctricas a carvão. As suas emissões poderiam ser reduzidas substituindo parte dos combustíveis fósseis por combustíveis considerados como sendo neutros na emissão efectiva de CO2, como a biomassa e alguns resíduos. As quantidades de biomassa e resíduos disponíveis não são suficientes para satisfazer as necessidades energéticas do país, pelo que, o seu uso em co-combustão poderá diminuir o fluxo líquido de CO2 para a atmosfera, numa prespectiva de substituição parcial do carvão. Como a combustão de carvão origina níveis elevados de NOX e de SO2, devido à presença de azoto e de enxofre no combustível, são necessárias medidas para minimizar a sua formação e consequente emissão. Utilizando combustíveis auxiliares com menores teores em azoto e em enxofre em co-combustão, as quantidades de poluentes formados poderão decrescer. Mais ainda, dependendo da natureza do azoto no combustível, a formação de NOX pode ser reduzida durante a co-combustão. A adição de calcário é utilizada para remoção do SO2, no entanto, isto poderá favorecer o aumento do NOX pelo que terão de ser tomadas medidas para evitar este fenómeno. Por outro lado, a queima de resíduos minimiza os problemas físicos, em termos de espaço, associados à sua deposição em aterro. Por combustão pode-se diminuir em cerca de 60 a 80 % a sua massa e até cerca de 90 % do seu volume (no caso dos CDR). O carvão poderá desempenhar um efeito estabilizador em termos do processo de queima e em termos de garantia de disponibilidade contínua de combustível. Relativamente às emissões de outros poluentes como o mercúrio e outros metais pesados, e cloro, a utilização da co-combustão com o carvão poderá diminuir a sua emissão especialmente quando utilizado juntamente com os resíduos do tipo do CDR e da LRU. A opção pela co-combustão introduz algumas vantagens que poderão ser maximizadas jogando com as percentagens relativas dos combustíveis envolvidos. Este trabalho mostrou que é possível alcançar uma sinergia positiva na redução dos níveis de CO, NOX, N2O, SO2, HCl e mercúrio durante a co-combustão de carvão com cinco diferentes combustíveis auxiliares. Mais ainda, ficou demonstrada a redução nas quantidades de CO2 libertadas o que enaltece e reforça a opção pela co-combustão. O âmbito deste trabalho poderá ser estendido a outros poluentes e a outros tipos de biomassa e resíduos para optimizar as emissões

Relatório de estágio

RESUMO Neste relatório de estágio está contida informação relativa ao percurso de aprendizagem realizado na empresa TE Connectivity de Évora. A aprendizagem consistiu num conhecimento focado para a tecnologia do relé. Sendo o relé um componente eletromecânico engloba ter um conhecimento sobre várias áreas científicas nomeadamente, a Física , a Química, a Eletrónica, o Magnetismo e a Mecânica. O conteudo do relatório contém uma descrição do funcionamento básico, os vários tipos de relés existentes, suas características, testes mais importantes e necessários para a validação (para relés de sinal), aparelhos e métodos de medição utilizados, as principais aplicações dos relés e no ultimo capitulo uma descrição das aplicações práticas desenvolvidas de modo a possibitar a análise dos relés.Instituto Politécnico de Toma

Waste tyres valorisation through gasification in a bubbling fluidised bed: An exhaustive gas composition analysis

Waste tyres gasification in a bubbling fluidised bed reactor is evaluated by means of a complete characterisation of the product gas. The experiments are carried out at two temperatures, 700 and 850 degrees C, and various equivalence ratios (ER) while using air as a gasifying. Additionally, the effect of steam is also studied at 850 degrees C. High temperature and low ER increase the production of H2, CH4, and C2H4. Steam addition mainly affects H2 and CO production. Low carbon conversion (CC) into gas and cold gas efficiency (CGE) are obtained, increasing with temperature and ER. The lower heating value (LHV) of the gas decreases with the ER because of the higher partial combustion rates. LHV values range between 12 MJ/Nm3 with steam addition at ER = 0.13 and 850 degrees C to 5.3 MJ/Nm3 at ER = 0.33 and 700 degrees C using air only. Along with a major permanent gas (CO2, CO, H2, CH4, and C2Hn), up to 25 short-chain hydrocarbons (non-aromatic hydrocarbons ranging from C3 to C6+) and two light aromatics are present in the product gas. Among short-chain hydrocarbons, C3 and C4 compounds are present in the highest yields. All these minor hydrocarbon species (i.e., C3 to C6+), not usually reported in biomass or waste gasification studies, yield up to 13 %vol. on a N2-free basis. Their contribution to the gasification performance is important because they account for half of the energy content in the product gas. Therefore, it is important to consider them in the gasification process, not only for energy purposes but also for the chemical industry.This research has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 731101 (BRISK II project: Biofuels Research Infrastructure for Sharing Knowledge II). Funding for APC: Universidad Carlos III de Madrid (Read & Publish Agreement CRUE-CSIC 2022)

Evaluation of slagging and fouling tendency during biomass co-firing with coal in a fluidized bed

Over the last decades, several indices based on ash chemistry and ash fusibility have been used to predict the ash behaviour during coal combustion, namely, its tendency for slagging and fouling. However, due to the physicalechemical differences between coals and biomass, in this work only the applicability of an ash fusibility index (AFI) to the combustion and co-combustion of three types of biomass (straw pellets, olive cake and wood pellets) with coals was evaluated. The AFI values were compared with the behaviour of ash during combustion in a pilot fluidized bed and a close agreement was observed between them. For a better understanding of the mechanisms associated with bed ash sintering, they were evaluated by SEM/EDS and the elements present on the melted ash were identified. Evidences of different sintering mechanisms were found out for the fruit biomass and herbaceous biomass tested, depending on the relative proportions of problematic elements. The particles deposited on a fouling probe inserted in the FBC were analyzed by XRD and the differences between the compounds identified allowed concluding that the studied biomasses present different tendencies for fouling. Identification of KCl and K2SO4 in the deposits confirmed the higher tendency for fouling of fruit biomass tested rather than wood pellets

Prediction of COVID-19 diagnosis based on openEHR artefacts

Nowadays, we are facing the worldwide pandemic caused by COVID-19. The complexity and momentum of monitoring patients infected with this virus calls for the usage of agile and scalable data structure methodologies. OpenEHR is a healthcare standard that is attracting a lot of attention in recent years due to its comprehensive and robust architecture. The importance of an open, standardized and adaptable approach to clinical data lies in extracting value to generate useful knowledge that really can help healthcare professionals make an assertive decision. This importance is even more accentuated when facing a pandemic context. Thus, in this study, a system for tracking symptoms and health conditions of suspected or confirmed SARS-CoV-2 patients from a Portuguese hospital was developed using openEHR. All data on the evolutionary status of patients in home care as well as the results of their COVID-19 test were used to train different ML algorithms, with the aim of developing a predictive model capable of identifying COVID-19 infections according to the severity of symptoms identified by patients. The CRISP-DM methodology was used to conduct this research. The results obtained were promising, with the best model achieving an accuracy of 96.25%, a precision of 99.91%, a sensitivity of 92.58%, a specificity of 99.92%, and an AUC of 0.963, using the Decision Tree algorithm and the Split Validation method. Hence, in the future, after further testing, the predictive model could be implemented in clinical decision support systems.This work is funded by "FCT-Fundacao para a Ciencia e Tecnologia" within the R &D Units Project Scope: UIDB/00319/2020. D.F. thanks the FundacAo para a Ciencia e Tecnologia (FCT), Portugal for the Grant 2021.06308.BD

An OpenEHR adoption in a portuguese healthcare facility

The quality and safety of clinical decisions depend to a large extent on the knowledge acquired by the records of health professionals. However, a traditional Electronic Health Record (EHR) has become insufficient in terms of knowledge acquisition and clinical decision support. The development of these aspects may bring marked improvements in the quality and safety of health care. The usage of open models promotes interoperability between systems, minimizing the impact of information systems on the efficient production of knowledge useful for clinical decisions. In this sense, this article describes an implementation project of a system that support the production and use of knowledge in clinical environments, based on OpenEHR two levels modelling open data approach, in a healthcare facility on the north of Portugal.he work has been supported by FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/202

Gasification improvement of a poor quality solid recovered fuel (SRF): Effect of using natural minerals and biomass wastes blends

The need to produce energy from poor quality carbonaceous materials has increased, in order to reduce European dependency on imported fuels, diversify the use of new and alternative fuels and to guarantee secure energy production routes. The valorisation of a poor quality solid residual fuel (SRF), with high content of ash and volatile matter, through its conversion into fuel gas was studied. The rise of gasification temperature and equivalent ratio (ER) led to higher gas yields and to lower undesirable gaseous components, though higher ER values led to a gas with lower energetic content. To reduce the negative effect of SRF unfavourable characteristics and to diversify the feedstocks used, SRF blended with three different types of biomass wastes: forestry pine, almond shells and olive bagasse was co-gasified. The use of biomass wastes tested was valuable for SRF gasification, as there was an increase in the overall reactivity and in H2 production and a reduction of about 55% in tar released, without great changes in gas yield and in its HHV. The use of natural minerals mixed with silica sand was also studied with the aim of improving SRF gasification performance and fuel gas quality. The best results were obtained in presence of dolomite, as the lowest tar and H2S contents were obtained, while an increase in gas yield was observed. Co-gasification of this poor quality SRF blended with biomass wastes in presence of dolomite increased gas yield by 25% while tar contents decreased by 55%

Knowledge discovery for pervasive and real-time intelligent decision support in intensive care medicine

Pervasiveness, real-time and online processing are important requirements included in the researchers’ agenda for the development of future generation of Intelligent Decision Support Systems (IDSS). In particular, knowledge discovery based IDSS operating in critical environments such of intensive care, should be adapted to those new requests. This paper introduces the way how INTCare, an IDSS developed in the intensive care unit of the Centro Hospitalar do Porto, will accommodate the new functionalities. Solutions are proposed for the most important constraints, e.g., paper based data, missing values, values out- of-range, data integration, data quality. The benefits and limitations of the approach are discussed.Fundação para a Ciência e a Tecnologia (FCT) - PTDC/EIA/72819/ 2006, SFRH/BD/70156/201

OpenEHR modeling: improving clinical records during the COVID-19 pandemic

The COVID-19 pandemic had put pressure on various national healthcare systems, due to the lack of health professionals and exhaustion of those avaliable, as well as lack of interoperability and inability to restructure their IT systems. Therefore, the restructuring of institutions at all levels is essential, especially at the level of their information systems. Furthermore, the COVID-19 pandemic had arrived in Portugal at March 2020, with a breakout on the northern region. In order to quickly respond to the pandemic, the CHUP healthcare institution, known as a research center, has embraced the challenge of developing and integrating a new approach based on the openEHR standard to interoperate with the institution’s existing information and its systems. An openEHR clinical modelling methodology was outlined and adopted, followed by a survey of daily clinical and technical requirements. With the arrival of the virus in Portugal, the CHUP institution has undergone through constant changes in their working methodologies as well as their openEHR modelling. As a result, an openEHR patient care workflow for COVID-19 was developed.This work has been supported by FCT - Fundacao para a Ciuencia e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020

Steps towards an Healthcare Information Model based on openEHR

During COVID-19 pandemic crisis, healthcare institutions globally were experiencing a VUCA - Volatile, Uncertain, Complex, and Ambiguous - environment. Efficient clinical and administrative management had never been so emergent. To achieve this goal, different components of the Healthcare Information System (HIS) must cooperate and interoperate flawlessly. Data standardization is a necessary step towards normalization and interoperability between existing Legacy Systems (LSs), and provides for longitudinal, highly reliable and persistent Electronic Health Records (EHRs). The openEHR standard was chosen for its overall dual domain architecture, where the more dynamic clinical information model may evolve independently from the relatively stable Reference Model (RM). Its Information Model (IM) comprises demographic, administrative and clinical systems. Critical clinical terms have been aligned to the FHIR HL7 standard, as to further support interoperability.This work has been supported by FCT -Fundacao para a Ciencia e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020