Análise exploratória aplicada a espectros de reflexão total atenuada no infravermelho com transformada de Fourier (ATR-FTIR) de blendas de biodiesel/diesel

In this study, hierarchical cluster analysis (HCA) and principal component analysis (PCA) were used to classify blends produced from diesel S500 and different kinds of biodiesel produced by the TDSP methodology. The different kinds of biodiesel studied in this work were produced from three raw materials: soybean oil, waste cooking oil and hydrogenated vegetable oil. Methylic and ethylic routes were employed for the production of biodiesel. HCA and PCA were performed on the data from attenuated total reflectance Fourier transform infrared spectroscopy, showing the separation of the blends into groups according to biodiesel content present in the blends and to the kind of biodiesel used to form the mixtures.

DETERMINAÇÃO DO TEOR DE BIODIESEL EM DIESEL EMPREGANDO O ENSAIO COLORIMÉTRICO DO ÁCIDO HIDROXÂMICO

The aim of this paper was to use colorimetric assays for hydroxamic acid to quantify the biodiesel content in diesel and compare it with the traditional method (infrared spectroscopy, using the EN 14078 method). Samples were prepared from B2 to B10 with two kinds of diesel - S500 (red) and S50 (yellow) - to obtain two calibration curves. Through statistical methods it was shown that the slopes of the straight lines obtained for the different types of diesel were the same. Thus, the type of diesel did not influence the results of the colorimetric assay for hydroxamic acid. Real samples collected from gas stations were analyzed by both methods (colorimetry and EN 14078). By applying Student's t-test it was concluded that the methods could be considered statistically equivalent. Therefore, it was confirmed that the colorimetric assay for hydroxamic acid is suitable for detecting and quantifying the content of biodiesel in biodiesel/diesel blends and can also be easily adapted to field analyses.

Effect of forest-based biofuels production on carbon footprint, Case: Integrated LWC paper mill

International energy and climate strategies also set Finland’s commitments to increasing the use of renewable energy sources and reducing greenhouse gas emissions. The target can be achieved by, for example, increasing the use of energy wood. Finland’s forest biomass potential is significant compared with current use. Increased use will change forest management and wood harvesting methods however. The thesis examined the potential for integrated pulp and paper mills to increase bioenergy production. The effects of two bioenergy production technologies on the carbon footprint of an integrated LWC mill were studied at mill level and from the cradle-to-customer approach. The LignoBoost process and FT diesel production were chosen as bioenergy cases. The data for the LignoBoost process were obtained from Metso and for the FT diesel process from Neste Oil. The rest of the information is based on the literature and databases of the KCL-ECO life-cycle computer program and Ecoinvent. In both case studies, the carbon footprint was reduced. From the results, it can be concluded that it is possible to achieve a fossil-fuel-free pulp mill with the LignoBoost process. By using steam from the FT diesel process, the amount of auxiliary fuel can be reduced considerably and the bark boiler can be replaced. With a choice of auxiliary fuels for use in heat production in the paper mill and the production methods for purchased electricity, it is possible to affect the carbon footprints even more in both cases.

Determination of Copper, Iron, Nickel and Zinc in fuel kerosene by FAAS after adsorption and pre-concentration on 2-aminothiazole-modified silica gel

Silica gel chemically modified with 2-Aminotiazole groups, abbreviated as SiAT, was used for preconcentration of copper, zinc, nickel and iron from kerosene, normally used as a engine fuel for airplanes. Surface characteristics and surface area of the silica gel were obtained before and after chemical modification using FT-IR, Kjeldhal and surface area analysis (B.E.T.). The retention and recovery of the analyte elements were studied by applying batch and column techniques. The experimental parameters, such as shaking time in batch technique, flow rate and concentration of the eluent (HCl- 0.25-2.00 mol L-1) and the amount of silica, on retention and elution, have been investigated. Detection limits of the method for copper, iron, nickel and zinc are 0.77, 2.92, 1.73 and 0.097 mg L-1, respectively. The sorption-desorption of the studied metal ions made possible the development of a preconcentration method for metal ions at trace level in kerosene using flame AAS for their quantification.

Parallel-Operating Three-Phase Voltage Source Inverters – Circulating CurrentModeling, Analysis and Mitigation

The maximum realizable power throughput of power electronic converters may be limited or constrained by technical or economical considerations. One solution to this problemis to connect several power converter units in parallel. The parallel connection can be used to increase the current carrying capacity of the overall system beyond the ratings of individual power converter units. Thus, it is possible to use several lower-power converter units, produced in large quantities, as building blocks to construct high-power converters in a modular manner. High-power converters realized by using parallel connection are needed for example in multimegawatt wind power generation systems. Parallel connection of power converter units is also required in emerging applications such as photovoltaic and fuel cell power conversion. The parallel operation of power converter units is not, however, problem free. This is because parallel-operating units are subject to overcurrent stresses, which are caused by unequal load current sharing or currents that flow between the units. Commonly, the term ’circulatingcurrent’ is used to describe both the unequal load current sharing and the currents flowing between the units. Circulating currents, again, are caused by component tolerances and asynchronous operation of the parallel units. Parallel-operating units are also subject to stresses caused by unequal thermal stress distribution. Both of these problemscan, nevertheless, be handled with a proper circulating current control. To design an effective circulating current control system, we need information about circulating current dynamics. The dynamics of the circulating currents can be investigated by developing appropriate mathematical models. In this dissertation, circulating current models aredeveloped for two different types of parallel two-level three-phase inverter configurations. Themodels, which are developed for an arbitrary number of parallel units, provide a framework for analyzing circulating current generation mechanisms and developing circulating current control systems. In addition to developing circulating current models, modulation of parallel inverters is considered. It is illustrated that depending on the parallel inverter configuration and the modulation method applied, common-mode circulating currents may be excited as a consequence of the differential-mode circulating current control. To prevent the common-mode circulating currents that are caused by the modulation, a dual modulator method is introduced. The dual modulator basically consists of two independently operating modulators, the outputs of which eventually constitute the switching commands of the inverter. The two independently operating modulators are referred to as primary and secondary modulators. In its intended usage, the same voltage vector is fed to the primary modulators of each parallel unit, and the inputs of the secondary modulators are obtained from the circulating current controllers. To ensure that voltage commands obtained from the circulating current controllers are realizable, it must be guaranteed that the inverter is not driven into saturation by the primary modulator. The inverter saturation can be prevented by limiting the inputs of the primary and secondary modulators. Because of this, also a limitation algorithm is proposed. The operation of both the proposed dual modulator and the limitation algorithm is verified experimentally.

Formation of polyelectrolyte multilayers and polyelectrolyte complexes in dual polymer treatment of papermaking pulp

The goal of this study was to find a new approach to modify chemically the properties of paper by improving fiber quality. This Master’s thesis includes the multiple polymer treatment in general and themeasurement methods with which the formation of multilayers and complexes can be noticed. The treatment by an oppositely charged dual polymer system is a good approach to increase paper strength. In this work, starch, a cationic polymer, and carboxymethyl cellulose (CMC), an anionic polymer, were used step-by-step to improve paper strength. The adsorption of cationic starch and CMC on cellulose fibers were analyzed via polyelectrolyte titration. The results showed that paper strength was enhanced slightly with a layer-by-layer assembly of the polymers. However, if the washing stage, which was required for layer-by-layer assembly, was eliminated, the starch/CMC complex was deposited on fibers more efficiently, and the paper strength was improved more significantly.

Energiavarastojen mitoitus laivasähköjärjestelmään

Jatkuvasti kiristyvät päästörajoitukset ajavat eri alojen energiatuottajia kehittämään uusia ratkaisuja päästöjen pienentämiseksi. Viime aikoina myös laivojen päästörajoituksia on tiukennettu ja tulevaisuudessa niitä tullaan tiukentamaan lisää. Nämä tiukentuvat päästörajoitukset asettavat myös laivan dieselmoottoreiden valmistajat uusien haasteiden eteen. Yhtenä vaihtoehtona on lisätä dieselmoottorin rinnalle energiavarasto, joka vähentää dieselmoottorin päästöjä varsinkin nopeissa kuormituksen muutoksissa. Tässä diplomityössä tarkastellaan sähköisten energiavarastojen mitoitusta laivan sähköjärjestelmään. Energiavarastot mitoitetaan useaan eri toimintatilanteeseen. Mitoituksen lisäksi pohditaan energiavarastoilla saatavaa mahdollista rahallista hyötyä sekä päästöjen vähenemistä.

Design of marine generators for alternative diesel-electric power systems

This study compares different electric propulsion systems. Results of the analysis of all the advantages and disadvantages of the different propulsion systems are given. This thesis estimates possibilities to apply different diesel-electric propulsion concepts for different vessel types. Small and medium size vessel’s power ranges are studied. The optimal delivery system is chosen. This choice is made on the base of detailed study of the concepts, electrical equipment market and comparison of mass, volume and efficiency parameters. In this thesis three marine generators are designed. They are: salient pole synchronous generator and two permanent magnet synchronous generators. Their electrical, dimensional, cost and efficiency parameters are compared. To understand all the benefits diagrams with these parameters are prepared. Possible benefits and money savings are estimated. As the result the advantages, disadvantages and boundary conditions for the permanent magnet synchronous generator application in marine electric-power systems are found out.

Energiapuun haketuksen ja murskauksen kustannukset

Energiapuun tuotannossa puu on hienonnettava kuljettimille ja kattilaan sopivaan kokoon. Tämä tehdään Suomessa yleensä joko metsätien varressa välivarastolla, keskitetyssä terminaalissa tai voimalaitoksella. Puu hienonnetaan joko terävillä terillä hakettamalla tai tylpemmillä työkaluilla murskaamalla. Hakkeessa on vähemmän käsittelyä haittaavia pitkiä tikkuja ja sen valmistamiseen tarvittava energia on hiukan pienempi kuin murskaimilla. Viimeksi mainitulla on merkitystä lähinnä karsittua puuta haketettaessa. Murskain puolestaan sallii enemmän epäpuhtauksia raaka-aineessa, joten esimerkiksi kantoja käsitellään vain murskaimilla. Tässä tarkastellaan erityisesti pienpuun haketuksen ja murskauksen kustannuksia. Pienpuuta saadaan nuoren metsän kunnostuksista ja ensiharvennuksista. Se voi olla joko karsimatonta kokopuuta tai karsittua rankaa. Kokonaiskustannukset pienpuun haketukselle tai murskaukselle ovat tämän tutkimuksen mukaan välivarastolla noin 3,4 euroa/MWh ja terminaalilla tai voimalaitoksella noin 2 euroa/MWh. Pääomakustannukset ovat pienpuulla tavallisesti 1-1,2 euroa/MWh, keskitetyllä terminaalilla toimittaessa noin kolmanneksen vähemmän, jos pääomalle asetetaan 10% tuottovaatimus. Työvoimakustannukset ovat 30-80 snt/MWh varaston ja laitteen koosta riippuen, käyttöenergia dieselmoottoria käytettäessä noin 50 snt/MWh, sähkömoottorilla noin 30 snt/MWh. Muut kulut, mm. huolto, ovat yhteensä 40-80 snt/MWh. Energiapuun hankinnan kokonaiskustannuksista raaka-aineen hienontamisen osuus on 10-30% puutavaran lajista ja käytetystä työmenetelmästä riippuen. Terminaaleilla ja voimalaitoksilla toimittaessa on usein kiinnitettävä huomiota melun- ja pölyntorjuntaan. Muun muassa näistä syistä saattaa kiinteä, sähkökäyttöinen murska olla sopiva sellaisiin kohteisiin, joissa käsiteltävät määrät ovat suuria ja toiminta pysyvää. Melun ja pölyn kunnollinen torjunta vaatii suuria rakenteita, joita on vaikea yhdistää liikuteltaviin laitteisiin.

Dieselmoottorisen kaupunkilinja-auton muuttaminen sarjahybridiajoneuvoksi

Tutkimus on pohjustusta Lappeenrannan teknillisen yliopiston Green Campus–hankkeessa tulevaisuudessa mahdollisesti rakennettavalle Cambus–hybridibussille ja siihen liittyvälle muutostyölle. Tässä tutkimuksessa käsitellään asioita, joita kohdataan kun tavallinen dieselkäyttöinen linja–auto muutetaan hybridiajoneuvoksi. Työ sisältää teoriaosuuden, jossa esitellään peruskomponentteja esimerkiksi moottoreiden ja energianvarastointitekniikoiden osalta sekä uusimpia kehityskohteita polttomoottoreiden osalta. Tutkimuksessa on myös vertailtu erilaisia hybridivaihtoehtoja sekä käsitelty mm. tasauspyörästön välityssuhteen ja vaihteiston vaikutusta bussin teoreettiseen suorituskykyyn. Tehdyn tutkimustyön perusteella on hahmoteltu eräs mahdollinen sarjahybridibussin voimansiirtolinja esimerkkikomponentteineen. Tutkimuksessa esitetään myös laskelmia järjestelmän teoreettisesta polttoaineenkulutuksesta jarrutusenergian talteenotto huomioiden perinteiseen kaupunkilinja-autoon verrattuna.

Comportamento de um motor de ignição por compressão trabalhando com óleo Diesel e gás natural

A previsível escassez de petróleo aliada a uma consciência ecológica está levando pesquisadores a procurar novas fontes de energia e processos de combustão mais eficientes e menos poluentes. Entre os combustíveis menos poluentes está o gás natural, cujo consumo aumenta ano a ano. Os motores de combustão interna são transformadores de energia que têm baixa eficiência de conversão. Este trabalho avaliou um motor Diesel, bicombustível, movido a Diesel e gás natural. Nesse motor, a energia provém, basicamente, da combustão do gás natural. O Diesel tem a função de produzir o início da combustão do gás, que é o combustível principal. Assim, haverá uma substituição parcial de óleo Diesel por gás natural, aumentando o rendimento da combustão. Inicialmente, foi feito um ensaio-testemunha, somente com óleo Diesel e após foram feitos ensaios, com três repetições, para variadas proporções de óleo Diesel, gás natural e ângulos de avanço da injeção. O melhor desempenho foi obtido para 22% de óleo Diesel em relação ao máximo débito da bomba injetora e 13 L min-1 de gás natural com ângulo de avanço de injeção original (21º). Nesse caso, a potência média aumentou 14%, e o consumo específico (medido em valores monetários) diminuiu 46% em relação ao ensaio-testemunha.