Hochschule für Technik und Umwelt FHNW
Dauerhafte URI für den Bereichhttps://irf.fhnw.ch/handle/11654/35
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Bereich: Suchergebnisse
Publikation Technology in motion(UKIP Media & Events Ltd., 2018) Simons, Gerd; Pospisek, Tomas01B - Beitrag in Magazin oder ZeitungPublikation Method of mounting a weigh-in-motion sensor in a roadway(Kistler Holding AG, 01.03.2019) Simons, Gerd; Pfluger, Kim12 - PatentPublikation Windsichter mit Zyklon(Hochschule für Technik FHNW, 27.03.2016) Cvetkovic, Darko; Vogel, FrédéricAusgangslage: Die Themen dieser Bachelor Thesis sind Windsichter und Zyklone. Die Arbeit ist eine Fortsetzung des Projekts P5 „Auslegung eines Zyklons zur Auftrennung von Holzstaub“. Der Auftraggeber dieser Projektarbeit ist Prof. Dr. Frédéric Vogel vom Institut für Biomasse und Ressourceneffizienz der Fachhochschule Nordwestschweiz. Ziel dieser Arbeit ist es, eine Anlage bestehend aus einem Windsichter und einem Zyklon als Vorzeigeobjekt für den Unterricht zu bauen. Die Anlage soll als Vorzeigeobjekt im Modul Verfahrenstechnik dienen, welches von Prof. Dr. Frédéric Vogel im Bachelor-Studiengang Energie- und Umwelttechnik unterrichtet wird. Vorgehen: Zu Beginn der Arbeit wurde die Auftragsklärung durchgeführt. Es galt herauszufinden wie eine Klassierung von mehreren hundert Kilogramm Holzstaub in wenigen Stunden zu bewerkstelligen und ob dies im Rahmen der Projektarbeit realisierbar ist. Dies wurde aufgrund der resultierenden Anlagegrösse und möglicher Kosten verworfen und der Fokus wurde auf eine Anlage gelegt, welche als Vorzeigeobjekt im Unterricht genutzt werden kann. Nach der Auftragsklärung wurde das Basic Engineering gestartet. Für die Anlage wurde nach passenden Komponenten gesucht. Diese wurden in die Auslegungsberechnungen eingesetzt und mit Hilfe eines 3D-CAD Models wurde die Anlage entwickelt. Daraufhin wurden Offerten eingeholt und eine Budgetabschätzung erstellt, um die Finanzierung des Projektes zu klären. Im Detail Engineering wurde das Model optimiert, Fertigungszeichnungen erstellt und Komponenten bestellt. Nach dieser Phase folgten die Montage, Inbetriebnahme und ein erster Funktionstest. Hauptergebnisse: Die Anlage wurde im Rahmen der Projektarbeit ausgelegt, gebaut, in Betrieb genommen und getestet. Sie steht als Vorzeigeobjekt für den Unterricht zur Verfügung. Der Windsichter, die Rohrleitungen, der Behälter für das Aufgabegut, die Kübel und der Zyklon wurden aus durchsichtigem Kunststoff hergestellt. Dies erlaubt einen Einblick in die einzelnen Trennprozesse der Anlage sowie die Transportprozesse in den Rohrleitungen. Der Ventilator, der Frequenzumrichter und das Manometer sind in der Anlage fest installiert. Über den Frequenzumrichter lassen sich die Drehzahl des Ventilators und so der Luft-Volumenstrom in der Anlage steuern. Für das Aufgabegut im Unterricht wurde Kunststoffgranulat aus Polypropylen gewählt. Ein kleiner Teil des Aufgabeguts wurde geschreddert, um eine Partikelgrössenverteilung im Aufgabegut zu erreichen. Das Aufgabegut ist weich genug, um die Apparate und Rohre nicht zu verkratzen. Der Zyklon kann Partikel mit einem Durchmesser von 5 bis 25 μm abscheiden. Dies in Abhängigkeit der Beladung und des Volumenstroms. Um kleinere Partikel aus dem Luftstrom abzuscheiden, ist ein HEPA-Filter am Luftaustritt des Zyklons installiert worden. Die Luftgeschwindigkeit im Windsichter kann über den Luft-Volumenstrom berechnet werden. Den Luft-Volumenstrom kann man mithilfe der Irisblende bestimmen. Die Anlage ist in einem Gestell aus Aluminium-Profilen aufgebaut und das Gestell steht auf Rollen. Die Anlage ist so konzipiert, dass sie einfach transportiert werden kann und sie passt durch Türen und in einen Warenlift. Ausblick: Als Einsatzzweck für die Anlage sind Laborversuche für die Studierenden denkbar. Die Studierenden könnten Auslegungsrechnungen zu der gegebenen Anlage durchführen, diese mit einem Versuch auf die Probe stellen und die Resultate diskutieren. Es sind auch weitere Projekte möglich, um die Anlage zu verbessern oder zu erweitern. Die Dosiervorrichtung sollte überarbeitet werden. Zudem könnten weitere Messpunkte installiert wer-den. Es gibt Pläne, die Anlage für das Klassieren von kleinen Holzstaubchargen zu benutzen. Basierend darauf, ob sich der Windsichter für diese Aufgabe gut eignet, kann eine grössere Anlage gebaut werden, welche den gewünschten Durchsatz ermöglicht.11 - Studentische ArbeitPublikation Equation of state and thermodynamic properties for mixtures of H2O,O2, N2, and CO2 from ambient up to 1000 K and 280 MPa(Elsevier, 05.03.2019) Mangold, Fabienne; Pilz, Stephan; Bjelic, Sasa; Vogel, FrédéricSupercritical water oxidation (SCWO) is an effective technique to treat wet organic wastes. Its modeling requires an accurate calculation of thermodynamic properties. In this work an equation of state (EOS) is proposed which accurately predicts the thermodynamic state of mixtures of water, oxygen, nitrogen, and carbon dioxide for a wide range of compositions, temperatures, and pressures including supercritical conditions. The EOS includes a volume translation, an evolved alpha-function and non-quadratic mixing rules. The introduced parameters are regressed to experimental data. From the pressure-explicit EOS, enthalpy, specific heats at constant volume and constant pressure, and fugacity coefficients are derived and calculated. The binary mixtures H2O/O2, H2O/N2, H2O/CO2, N2/CO2 as well as the ternary mixture H2O/O2/N2 are well predicted by the proposed EOS with relative errors below 10% and 15%, respectively. The region of low temperature and high pressure is most difficult to predict with relative errors up to 20%.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Hydrothermal oxidation of fecal sludge. Experimental investigations and kinetic modeling(American Chemical Society, 17.10.2016) Hübner, Tobias; Roth, Markus; Vogel, FrédéricHydrothermal oxidation (HTO) provides an efficient technique to completely destroy wet organic wastes. In this study, HTO was applied to treat fecal sludge at well-defined experimental conditions. Four different kinetic models were adjusted to the obtained data. Among others, a distributed activation energy model (DAEM) was applied. A total of 33 experiments were carried out in an unstirred batch reactor with pressurized air as the oxidant at temperatures of <470 °C, oxygen-to-fuel equivalence ratios between 0 and 1.9, feed concentrations between 3.9 and 9.8 molTOC L−1 (TOC = total organic carbon), and reaction times between 86 and 1572 s. Decomposition of the fecal sludge was monitored by means of the conversion of TOC to CO2 and CO. In the presence of oxygen, ignition of the reaction was observed around 300 °C, followed by further rapid decomposition of the organic material. The TOC was completely decomposed to CO2 within 25 min at 470 °C and an oxygen-to-fuel equivalence ratio of 1.2. CO was formed as an intermediate product, and no other combustible products were found in the gas. At certain reaction conditions, the formation of unwanted coke and tarlike products occurred. The reaction temperature and oxygen-to-fuel equivalence ratio showed a significant influence on TOC conversion, while the initial TOC concentration did not. Conversion of TOC to CO2 could be well described with a first-order rate law and an activation energy of 39 kJ mol−1.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Evidence for the role of organics in aerosol particle formation under atmospheric conditions(National Academy of Sciences, 19.01.2010) Metzger, Axel; Verheggen, Bart; Dommen, Josef; Duplissy, Jonathan; Prévôt, André S.H.; Weingartner, Ernest; Riipinen, Ilona; Kulmala, Markku; Spracklen, Dominick V.; Carslaw, Kenneth S.; Baltensperger, UrsNew particle formation in the atmosphere is an important parameter in governing the radiative forcing of atmospheric aerosols. However, detailed nucleation mechanisms remain ambiguous, as laboratory data have so far not been successful in explaining atmospheric nucleation. We investigated the formation of new particles in a smog chamber simulating the photochemical formation of H2SO4 and organic condensable species. Nucleation occurs at H2SO4 concentrations similar to those found in the ambient atmosphere during nucleation events. The measured particle formation rates are proportional to the product of the concentrations of H2SO4 and an organic molecule. This suggests that only one H2SO4 molecule and one organic molecule are involved in the rate-limiting step of the observed nucleation process. Parameterizing this process in a global aerosol model results in substantially better agreement with ambient observations compared to control runs.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Aerosol nucleation and growth in a mixture of sulfuric acid/alpha-pinene oxidation products at the CERN CLOUD chamber(AIP Publishing, 2013) Tröstl, Jasmin; Bianchi, Federico; Kürten, Andreas; Rondo, Linda; Simon, Mario; Sarnela, Nina; Jokinen, Tuija; Heinritzi, Martin; Dommen, Josef; Kirkby, Jasper; Weingartner, Ernest; Baltensperger, Urs; DeMott, Paul J.; O'Dowd, Colin D.The role of α-pinene in aerosol nucleation and growth was investigated using the CERN CLOUD chamber, a nano scanning mobility particle sizer (nanoSMPS) and several condensation particle counters (CPCs) with different diameter cut-offs. Different oxidation conditions for α-pinene - OH⋅ vs. ozone oxidation - were considered to investigate their contributions to particle nucleation and growth. Results from the latest CERN experiment from fall 2012 (CLOUD 7) are presented.04B - Beitrag KonferenzschriftPublikation Explaining global surface aerosol number concentrations in terms of primary emissions and particle formation(Copernicus, 26.05.2010) Spracklen, Dominick V.; Carslaw, Kenneth S.; Merikanto, Joonas; Mann, Graham W.; Reddington, Carly L.; Pickering, S.; Ogren, John A.; Andrews, Elisabeth; Baltensperger, Urs; Weingartner, Ernest; Boy, Michael; Kulmala, Markku; Laakso, Lauri; Lihavainen, Heikki; Kivekäs, Niku; Komppula, Mika; Mihalopoulos, Ninolaos; Kouvarakis, Giorgos; Jennings, Stephen G.; O'Dowd, Collin D.; Birmili, Wolfram; Wiedensohler, Alfred; Weller, Rolf; Gras, John; Laj, Paolo; Sellegri, Karine; Bonn, Boris; Krejci, Radovan; Laaksonen, Ari; Hamed, Amar; Minikin, Andreas; Harrison, Roy Michael; Talbot, Robert; Sun, JunyingWe synthesised observations of total particle number (CN) concentration from 36 sites around the world. We found that annual mean CN concentrations are typically 300–2000 cm−3 in the marine boundary layer and free troposphere (FT) and 1000–10 000 cm−3 in the continental boundary layer (BL). Many sites exhibit pronounced seasonality with summer time concentrations a factor of 2–10 greater than wintertime concentrations. We used these CN observations to evaluate primary and secondary sources of particle number in a global aerosol microphysics model. We found that emissions of primary particles can reasonably reproduce the spatial pattern of observed CN concentration (R2=0.46) but fail to explain the observed seasonal cycle (R2=0.1). The modeled CN concentration in the FT was biased low (normalised mean bias, NMB=−88%) unless a secondary source of particles was included, for example from binary homogeneous nucleation of sulfuric acid and water (NMB=−25%). Simulated CN concentrations in the continental BL were also biased low (NMB=−74%) unless the number emission of anthropogenic primary particles was increased or a mechanism that results in particle formation in the BL was included. We ran a number of simulations where we included an empirical BL nucleation mechanism either using the activation-type mechanism (nucleation rate, J, proportional to gas-phase sulfuric acid concentration to the power one) or kinetic-type mechanism (J proportional to sulfuric acid to the power two) with a range of nucleation coefficients. We found that the seasonal CN cycle observed at continental BL sites was better simulated by BL particle formation (R2=0.3) than by increasing the number emission from primary anthropogenic sources (R2=0.18). The nucleation constants that resulted in best overall match between model and observed CN concentrations were consistent with values derived in previous studies from detailed case studies at individual sites. In our model, kinetic and activation-type nucleation parameterizations gave similar agreement with observed monthly mean CN concentrations.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation EUCAARI ion spectrometer measurements at 12 European sites – analysis of new particle formation events(Copernicus, 25.08.2010) Manninen, Hanna E.; Nieminen, Tuomo; Asmi, Eija; Gagné, Stéphanie; Häkkinen, Silja; Lehtipalo, Katrianne; Aalto, Pasi Pekka; Vana, Marko; Mirme, Aadu; Mirme, Sander; Hõrrak, Urmas; Plass-Dülmer, Christian; Stange, Gert; Kiss, Gyula; Hoffer, András; Törő, N.; Moerman, Marcel; Henzing, Bas; de Leeuw, Gerrit; Brinkenberg, Marcel; Kouvarakis, Giorgos N.; Bougiatioti, Aikaterini; Mihalopoulos, Nikolaos; O'Dowd, Colin D.; Ceburnis, Darius; Arneth, Almut; Svenningsson, Brigitta; Swietlicki, Erik; Tarozzi, Leone; Decesari, Stefano; Facchini, Maria Cristina; Birmili, Wolfram; Sonntag, André; Wiedensohler, Alfred; Boulon, Julien; Sellegri, Karine; Laj, Paolo; Gysel, Martin; Bukowiecki, Nicolas; Weingartner, Ernest; Wehrle, Günther; Laaksonen, Ari; Hamed, Amar; Joutsensaari, Jorma; Petäjä, Tuukka; Kerminen, Veli-Matti; Kulmala, MarkkuWe present comprehensive results on continuous atmospheric cluster and particle measurements in the size range ~1–42 nm within the European Integrated project on Aerosol Cloud Climate and Air Quality interactions (EUCAARI) project. We focused on characterizing the spatial and temporal variation of new particle formation events and relevant particle formation parameters across Europe. Different types of air ion and cluster mobility spectrometers were deployed at 12 field sites across Europe from March 2008 to May 2009. The measurements were conducted in a wide variety of environments, including coastal and continental locations as well as sites at different altitudes (both in the boundary layer and the free troposphere). New particle formation events were detected at all of the 12 field sites during the year-long measurement period. From the data, nucleation and growth rates of newly formed particles were determined for each environment. In a case of parallel ion and neutral cluster measurements, we could also estimate the relative contribution of ion-induced and neutral nucleation to the total particle formation. The formation rates of charged particles at 2 nm accounted for 1–30% of the corresponding total particle formation rates. As a significant new result, we found out that the total particle formation rate varied much more between the different sites than the formation rate of charged particles. This work presents, so far, the most comprehensive effort to experimentally characterize nucleation and growth of atmospheric molecular clusters and nanoparticles at ground-based observation sites on a continental scale.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Development of an airborne sensor for reliable detection of volcanic ash(IEEE, 2016) Weingartner, Ernest; Jurányi, Zsofia; Egli, Daniel; Steigmeier, Peter; Burtscher, HeinzThis sensor detects volcanic ash particles and distinguishes them from cloud droplets. Operated on an airplane, this detector can quantify the exposure to hazardous refractory ash and the in-situ measurement is not biased by the presence of cloud particles. A volcanic eruption emits a significant amount of hazardous ash particles into the air. If the event is strong enough, the volcanic ash plume can reach high altitudes and can be a serious security risk for airplanes. We have developed a new prototype aerosol sensor for the reliable detection of volcanic ash. The envisaged application is the employment of this new technique on board of passenger aircraft. It allows in-situ monitoring of the airplane's exposure to volcanic ash. The challenge of this development is the requirement that the sensor can distinguish cloud droplets (or ice crystals) from the hazardous refractory ash particles. At aviation altitudes, water droplets and ice crystals are often present in the particle size region of the ash (1-20 micrometer) and their concentrations can reach the levels that are considered as the limits of the different volcanic ash contamination zones. Therefore, it is crucial that the sensor can differentiate between volcanic ash and water or ice particles. The sensor measures the scattered light intensities from individual particles outside of the airplane cabin through a glass window. The desired discrimination is achieved with two lasers operating at different wavelengths. Ash concentrations (in terms of number and mass) are derived, and the exposure of the airplane is recorded and transmitted in real time to the pilot. The volcanic ash detector was tested in the laboratory with various test aerosols and micrometer-sized water droplets. Then, ground-based outdoor measurements were conducted and the instrument response to mineral dust (a surrogate for volcanic ash) and natural cloud droplets (and ice crystals) was investigated. In a next step, this new technique will be tested in summer 2016 on-board of a research aircraft.04B - Beitrag Konferenzschrift