Influence of mixed fuels combustion on boiler operation

The aim of this work is to study the effect of different fuel mixtures on the operation of circulating fluidized bed (CFB) boiler. The applicability of heat balance modeling software IPSEpro to simulate CFB boiler operation is also investigated. The work discusses various types of boilers and methods of boiler operation. The fuel properties and the possible fuel influence on the boiler efficiency are described. Various biofuel types that are possible to use in combination with other fuels are presented. Some examples of the fuel mixtures use are given. A CFB boiler model has been constructed using IPSEpro and applied to analyze boiler operation outside design conditions. In the simulations, the effect of different load levels and moisture contents for the fuel mixture has been studied.

Evaluation of the dioxin and furan formation thermodynamics in combustion processes of urban solid wastes

Specific combustion programs (Gaseq, Chemical equilibria in perfect gases, Chris Morley) are used to model dioxin and formation in the incineration processes of urban solid wastes. Thanks to these programs, it is possible to establish correlations with the formation mechanisms postulated in literature on the subject. It was found that minimum oxygen quantities are required to obtain a significant formation of these compounds and that more furans than dioxins are formed. Likewise, dioxin and furan formation is related to the presence of carbon monoxide, and dioxin and furan distribution among its different compounds depends on the chlorine and hydrogen relative composition. This is due to the fact that an increased chlorine availability leads to the formation of compounds bearing a higher chlorine concentration (penta-, hexa-, hepta-, and octachlorides), whereas an increased hydrogen availability leads to the formation of compounds bearing a lower chlorine number (mono, di-, tri-, and tetrachlorides).

Avaliação do desempenho analítico do método de determinação de TPH (Total Petroleum Hydrocarbon) por detecção no infravermelho

No presente trabalho os parâmetros de desempenho (validação intralaboratorial) da metodologia de determinação de TPH (Total Petroleum Hydrocarbons) foram determinados por detecção na região do infravermelho com o equipamento da Infracal TOG/TPH, visando aplicação em amostras de areia contaminadas com petróleo. Os ensaios foram realizados utilizando Óleo Marine Fuel 380, com densidade igual 0,987 g cm-3 e viscosidade de 5313 cP a 20°C. Este óleo foi fornecido pelo Centro de Pesquisa da Petrobrás (CENPES/PETROBRÁS/RJ), sendo o mesmo óleo derramado no acidente ocorrido em janeiro de 2000, na Baia de Guanabara, RJ, quando 1.300 m3 vazaram do duto que interliga a REDUC (Refinaria Duque de Caxias, RJ) ao terminal da Ilha d’Água/RJ, atingindo praias. Os resultados da validação indicaram que o desempenho da metodologia foi favorável à aplicação que se destina. Entre os parâmetros metrológicos obtidos neste trabalho, o limite de detecção do método foi de 4,06 mg L-1, consideravelmente inferior à faixa de concentração normalmente obtida para amostras em tais situações.

Model based study of a calcium oxide looping process for post-combustion carbon dioxide capture

Calcium oxide looping is a carbon dioxide sequestration technique that utilizes the partially reversible reaction between limestone and carbon dioxide in two interconnected fluidised beds, carbonator and calciner. Flue gases from a combustor are fed into the carbonator where calcium oxide reacts with carbon dioxide within the gases at a temperature of 650 ºC. Calcium oxide is transformed into calcium carbonate which is circulated into the regenerative calciner, where calcium carbonate is returned into calcium oxide and a stream of pure carbon dioxide at a higher temperature of 950 ºC. Calcium oxide looping has proved to have a low impact on the overall process efficiency and would be easily retrofitted into existing power plants. This master’s thesis is done in participation to an EU funded project CaOling as a part of the Lappeenranta University of Technology deliverable, reactor modelling and scale-up tools. Thesis concentrates in creating the first model frame and finding the physically relevant phenomena governing the process.

Flow injection visible diffuse reflectance quantitative analysis of total sulfur in biodiesel, in plant leaves and in natural waters

Flow injection (FI) methodology, using diffuse reflectance in the visible region of the spectrum, for the analysis of total sulfur in the form of sulfate, precipitated in the form of barium sulfate, is presented. The method was applied to biodiesel, to plant leaves and to natural waters analysis. The analytical signal (S) correlates linearly with sulfate concentration (C) between 20 and 120 ppm, through the equation S=-1.138+0.0934 C (r = 0.9993). The experimentally observed limit of detection is about 10 ppm. The mean R.S.D. is about 3.0 %. Real samples containing sulfate were analyzed and the results obtained by the FI and by the reference batch turbidimetric method using the statistical Student's t-test and F-test were compared.

Use Of Systems Approach with Total Quality Management in Industrial Organizations

The objective of the work has been to study why systems thinking should be used in combination with TQM, what are the main benefits of the integration and how it could best be done. The work analyzes the development of systems thinking and TQM with time and the main differences between them. The work defines prerequisites for adopting a systems approach and the organizational factors which embody the development of an efficient learning organization. The work proposes a model based on combination of an interactive management model and redesign to be used for application of systems approach with TQM in practice. The results of the work indicate that there are clear differences between systems thinking and TQM which justify their combination. Systems approach provides an additional complementary perspective to quality management. TQM is focused on optimizing operations at the operational level while interactive management and redesign of organization are focused on optimization operations at the conceptual level providing a holistic system for value generation. The empirical study demonstrates the applicability of the proposed model in one case study company but its application is tenable and possible also beyond this particular company. System dynamic modeling and other systems based techniques like cognitive mapping are useful methods for increasing understanding and learning about the behavior of systems. The empirical study emphasizes the importance of using a proper early warning system.

A study of combustion phenomena in circulating fluidized beds by developing and applying experimental and modelling methods for laboratory-scale reactors

The results shown in this thesis are based on selected publications of the 2000s decade. The work was carried out in several national and EC funded public research projects and in close cooperation with industrial partners. The main objective of the thesis was to study and quantify the most important phenomena of circulating fluidized bed combustors by developing and applying proper experimental and modelling methods using laboratory scale equipments. An understanding of the phenomena plays an essential role in the development of combustion and emission performance, and the availability and controls of CFB boilers. Experimental procedures to study fuel combustion behaviour under CFB conditions are presented in the thesis. Steady state and dynamic measurements under well controlled conditions were carried out to produce the data needed for the development of high efficiency, utility scale CFB technology. The importance of combustion control and furnace dynamics is emphasized when CFB boilers are scaled up with a once through steam cycle. Qualitative information on fuel combustion characteristics was obtained directly by comparing flue gas oxygen responses during the impulse change experiments with fuel feed. A one-dimensional, time dependent model was developed to analyse the measurement data Emission formation was studied combined with fuel combustion behaviour. Correlations were developed for NO, N2O, CO and char loading, as a function of temperature and oxygen concentration in the bed area. An online method to characterize char loading under CFB conditions was developed and validated with the pilot scale CFB tests. Finally, a new method to control air and fuel feeds in CFB combustion was introduced. The method is based on models and an analysis of the fluctuation of the flue gas oxygen concentration. The effect of high oxygen concentrations on fuel combustion behaviour was also studied to evaluate the potential of CFB boilers to apply oxygenfiring technology to CCS. In future studies, it will be necessary to go through the whole scale up chain from laboratory phenomena devices through pilot scale test rigs to large scale, commercial boilers in order to validate the applicability and scalability of the, results. This thesis shows the chain between the laboratory scale phenomena test rig (bench scale) and the CFB process test rig (pilot). CFB technology has been scaled up successfully from an industrial scale to a utility scale during the last decade. The work shown in the thesis, for its part, has supported the development by producing new detailed information on combustion under CFB conditions.

Development of chemical looping combustion process

Chemical looping combustion (CLC) provides a promising technology to help cut carbon dioxide emissions. CLC is based on separated oxidation and reduction processes. Oxygen carrier, which is made from metal and supporting material, is in continuous recirculation between the air and fuel reactors. The CLC process does not require separation unit for carbon dioxide. The fuel reactor can produce an almost pure carbon dioxide feed which decrease costs of carbon capture and storage (CCS). The CLC method is one of the most promising ones for energy efficient carbon capture. A large amount of literature was examined for this study and from it the most promising methods and designs were chosen. These methods and designs were combined as reactor system design which was then sized during the making of this thesis. Sizing was done with a mathematical model that was further improved during the study.

Effect of Potato virus X on total phenol and alkaloid contents in Datura stramonium leaves

The present paper reports results of the effect of Potato virus X (PVX) on the contents of total phenols and alkaloids in leaves of Datura stramonium. A significant decrease in the contents of phenols and alkaloids was observed in leaves inoculated with PVX (X-I). However, there was an increase in the percentage of phenols in leaves rubbed with phosphate buffer (C1-I) and in leaves from the nodes immediately above, possibly induced by mechanical injury. Gas chromatography/mass spectroscopy revealed amounts of scopolamine in samples submitted to all treatments, except X-I, in which the amount of this alkaloid was low. High amounts of an unidentified compound (molecular ion m/z 302 and a prominent peak at m/z 129) were noted in extracts from leaves X-I, C1-I and leaves from the nodes immediately above the leaves inoculated with PVX. It is suggested that the synthesis and accumulation of the unidentified compound is a result of stress from mechanical injury and virus inoculation.

Differentiation of Colletotrichum gloeosporioides isolates by using total proteins and esterase electrophoretic patterns and extracellular enzymes production

Isolates of Colletotrichum gloeosporioides (ISO-1, ISO-2, ISO-3, ISO-4, ISO-5 and ISO-6), the causal agent of anthracnose disease on mango fruits, were characterized by electrophoretic patterns of total proteins and esterase in polyacrylamida gel, and also, by production of extracellular enzymes on specific solid substrate. The electrophoretic analysis showed variation in number, intensity of coloration and position of the bands in the gel at each studied system tested. In contrast to the monomorphic behavior to total proteins, high esterase polymorfism was observed indicating difference among isolates. All isolates showed the activity of extracellular enzymes such as amylase, lipase, and protease with some variation among them. The proteolitic activity seemed to be more accentuated than the two other enzymes studied.

Importância das variáveis altura dominante e altura total em equaçõea hipsométricas e volumétricas

Este estudo foi conduzido, visando avaliar as seguintes hipóteses: a) equações hipsométricas devem ser obtidas por parcela, apenas em função do dap; e b) equações volumétricas devem ser locais, em função apenas do dap. Foram utilizados dados de quatro parcelas distribuídas ao acaso em um povoamento de eucalipto de 67,81 ha e de 50 parcelas distribuídas ao acaso em um povoamento de 121,3 ha, da mesma espécie. Em uma análise inicial, a fim de obter valores reais de altura total e de volume sólido, realizou-se uma cubagem rigorosa de todas as árvores das quatro parcelas. Foram utilizados, ainda, dados de 277 árvores cubadas rigorosamente nos povoamentos. Para avaliar a exatidão das estimativas e as hipóteses formuladas, empregou-se o procedimento estatístico proposto por Leite & Oliveira (2002). Com base nos resultados, as hipóteses a e b foram rejeitadas a 1% de probabilidade. Concluiu-se, portanto, que em um inventário florestal a variável Hd deve ser considerada e que as equações volumétricas devem ser regionais.

Dry biomass distribution in a cerrado sensu stricto site in Brazil central

The Cerrado has been the main source of firewood and charcoal in Brazil, but despite being one of the hot spots for conservation of the world's biodiversity, neither plantations of native species nor sustainable management has been adopted in the region. The aim of this work was to investigate the biomass distribution and the potential for energy production of the cerrado species. The study was conducted in a cerrado sensu stricto site at the Água Limpa Farm (15º 56'14'' S and 47º 46'08'' W) in the Cerrado Biosphere Reserve. An area of 63.54ha was divided in 20 x 50m plots and, a random sample consisting of ten of these plots, representing 1.56% of the study-site, was assessed. All woody individuals from 5 cm diameter at 30 cm above ground level were identified and measured. Each individual was felled, the twigs thinner than 3cm were discarded while the larger branches and the trunks, both with bark, were weighted separately. After that, 2.5cm transverse sections of the trunk with bark were taken at 0, 25, 50, 75 and 100% of the length. A similar sample was also taken at the base of each branch. A total of 47 species in 35 genera and 24 families were found, with an average density of 673 individuals per ha. The diameter distribution showed a reversed-J shape with 67% of the individuals up to 13cm, while the maximum diameter was 32.30cm. Seven species represented 72% of the total biomass. In general, the species with higher production per tree were among those with higher production per ha. This content was distributed by diameter classes, reaching a maximum of 2.5ton/ha between 9 to 13cm and then, decreasing to 0.96 ton/ha between 29 to 33cm diameter. Carbon sequestering was 6.2ton/ha (until the actual stage of cerrado) based on an average 50% carbon content in the dry matter. The heat combustion of the wood varied from 18,903kj/kg to 20,888kj/kg with an average of 19,942kj/kg. The smaller diameter classes fix more carbon due to the large number of small plants per ha. But, for a species that reached larger dimensions and contained individuals in all diameter classes, Vochysia thyrsoidea, one can verify an increase in carbon fixation from 1.41 kg/ha in the first class (5 to 9cm) to 138,3kg/ha in the last (25 to 33cm). That indicates that it is possible to select species that reach larger size with a higher capacity of carbon accumulation per plant. The species that reached larger dimensions, with a production per tree above average and had high calorific power values were Dalbergia miscolobium, Pterodon pubescens and Sclerolobium paniculatum. These species have potential for use in fuelwood plantations and sustainable management.

Liiketoimintamahdollisuudet sähköisessä liikkumisessa

Tässä työssä tarkastellaan pk-yrityksen kohtaamaa monimutkaista ja alati muuttuvaa toimintaympäristöä. Ympäristöään tarkkailemalla yritys pystyy varautumaan ja vastaamaan muutoksiin nopeasti ja toimintakykyään heikentämättä. Työssä käydään läpi tapoja, joilla toimintaympäristöä ja tulevaisuudessa mahdollisti tapahtuvia muutoksia tarkkaillaan sekä miten yritys voi strategiallaan vaikuttaa omaan ketteryyteensä. Työssä tutustutaan myös sähköisen liikkumisen toimialaan ja siinä odotettavissa oleviin muutoksiin. Liikkumisen sähköistymiseen on useita syitä. Sähköenergiaa voidaan tuottaa kulloinkin parhaasta käytettävissä olevasta vaihtoehdosta, eikä liikenteen energian käyttö ole enää vain öljystä riippuvainen. Sähköajoneuvoja käytettäessä energian kulutus myös pienenee, sillä energiaketjun kokonaishyötysuhde paranee sähkömoottoreiden paremman hyötysuhteen ansiosta. Lisäksi sähköajoneuvot eivät tuota käytössä lainkaan paikallisia ilmapäästöjä ja niissä on polttomoottoreita huomattavasti alhaisempi melutaso. Palvelusektorilla on entistä merkittävämpi rooli yhteiskunnassa, sillä jopa kaksi kolmasosaa Euroopan työpaikoista ja bruttokansantuotteesta tulee erilaisista palveluista. Palvelut ovat enenevästi muodostumassa tuottavuuden ja kasvun tekijäksi, lisäksi se on ainoa osa-alue Euroopan taloudessa, jolla on onnistuttu luomaan uusia työpaikkoja kahden viime vuosikymmenen aikana. Elmotion Oy onkin tarttumassa vapaa-ajalla tapahtuvaan palveluliiketoimintaan. Työssä tutustutaan muutamiin vaihtoehtoihin, joissa yritys voi tuottaa mielenkiintoista ja hauskaa tekemistä ympäristömyönteisellä teknologialla.

Modelo de predição para o volume total de Quaruba (Vochysia inundata ducke) via análise de fatores e regressão

Neste trabalho propôs-se um método para a construção de um modelo de regressão para determinar o Volume de Madeira Total da espécie florestal (Vochysia inundata ducke) Quaruba, em função de suas características (Diâmetro à Altura do Peito (DAP), Idade e Altura). O modelo foi determinado utilizando-se a técnica estatística multivariada de Análise de Fatores com do Método das Componentes Principais via Rotação Ortogonal do Tipo Varimax para Extração dos Fatores, procurando contornar o problema da Multicolinearidade. Por fim desenvolveu-se um modelo de Regressão Linear Simples com base nos Escores Fatoriais. O modelo determinado apresentou-se de fácil interpretação e utilização, usando-se um fator e proporcionando um bom ajuste (R² = 96 %) aos dados e uma boa capacidade preditiva. Ele atendeu a todas as suposições teóricas para sua existência e utilização.