Prácticas ambientales que benefician la sostenibilidad empresarial del sistema metro de las ciudades de Europa, Norteamérica y Latinoamérica

71 p.

Protótipo de um microgerador termoelétrico de estado sólido: cogeração a gás

The thermoelectric energy conversion can be performed directly on generators without moving parts, using the principle of SEEBECK effect, obtained in junctions of drivers' thermocouples and most recently in semiconductor junctions type p-n which have increased efficiency of conversion. When termogenerators are exposed to the temperature difference (thermal gradient) eletromotriz a force is generated inducing the appearance of an electric current in the circuit. Thus, it is possible to convert the heat of combustion of a gas through a burner in power, being a thermoelectric generator. The development of infrared burners, using porous ceramic plate, is possible to improve the efficiency of heating, and reduce harmful emissions such as CO, CO2, NOx, etc.. In recent years the meliorate of thermoelectric modules semiconductor (TEG's) has stimulated the development of devices generating and recovery of thermal irreversibility of thermal machines and processes, improving energy efficiency and exergy these systems, especially processes that enable the cogeneration of energy. This work is based on the construction and evaluation of a prototype in a pilot scale, for energy generation to specific applications. The unit uses a fuel gas (LPG) as a primary energy source. The prototype consists of a porous plate burner infrared, an adapter to the module generator, a set of semiconductor modules purchased from Hi-Z Inc. and a heat exchanger to be used as cold source. The prototype was mounted on a test bench, using a system of acquisition of temperature, a system of application of load and instrumentation to assess its functioning and performance. The prototype had an efficiency of chemical conversion of 0.31% for electrical and heat recovery for cogeneration of about 33.2%, resulting in an overall efficiency of 33.51%. The efficiency of energy exergy next shows that the use of primary energy to useful fuel was satisfactory, although the proposed mechanism has also has a low performance due to underuse of the area heated by the small number of modules, as well as a thermal gradient below the ideal informed by the manufacturer, and other factors. The test methodology adopted proved to be suitable for evaluating the prototype

Análise do desempenho de um queimador infravermelho funcionando com gás liquefeito de petróleo e glicerina

The use of infrared burners in industrial applications has many advantages in terms of technical-operational, for example, uniformity in the heat supply in the form of radiation and convection, with greater control of emissions due to the passage of exhaust gases through a macro-porous ceramic bed. This paper presents an infrared burner commercial, which was adapted an experimental ejector, capable of promoting a mixture of liquefied petroleum gas (LPG) and glycerin. By varying the percentage of dual-fuel, it was evaluated the performance of the infrared burner by performing an energy balance and atmospheric emissions. It was introduced a temperature controller with thermocouple modulating two-stage (low heat / high heat), using solenoid valves for each fuel. The infrared burner has been tested and tests by varying the amount of glycerin inserted by a gravity feed system. The method of thermodynamic analysis to estimate the load was used an aluminum plate located at the exit of combustion gases and the distribution of temperatures measured by a data acquisition system which recorded real-time measurements of the thermocouples attached. The burner had a stable combustion at levels of 15, 20 and 25% of adding glycerin in mass ratio of LPG gas, increasing the supply of heat to the plate. According to data obtained showed that there was an improvement in the efficiency of the 1st Law of infrared burner with increasing addition of glycerin. The emission levels of greenhouse gases produced by combustion (CO, NOx, SO2 and HC) met the environmental limits set by resolution No. 382/2006 of CONAMA

Aplicabilidad del plan de sostenibilidad ambiental de la Empresa Volkswagen

108 p.

Evaluación de los impactos ambientales de una incineradora de residuos sólidos urbanos con recuperación de energía mediante el análisis de ciclo de vida

La generación de Residuos Sólidos Urbanos (RSU) se encuentra en continuo aumento y la actividad económica vinculada a los residuos alcanza cada vez mayor importancia. La gestión de los RSU se puede abordar desde dos estrategias básicas: el tratamiento de los residuos producidos, previo vertido o almacenamiento, y la adopción de medidas que eviten o minimicen la eliminación de los mismos. La incineración de residuos está asociada a la primera estrategia, consiguiendo la reducción del volumen de los mismos y en algunos casos el aprovechamiento de su energía. Las incineradoras de RSU son objeto de críticas desde el punto de vista medioambiental, debido a la formación de contaminantes que puedan ser emitidos por estas instalaciones. Para evaluar sus potenciales impactos vamos a utilizar el Análisis de Ciclo de Vida (ACV) que consiste en una metodológica que determina los potenciales impactos ambientales asociados con un producto o servicio, desde la extracción de la materia prima hasta su disposición final. En este trabajo se realiza, mediante la metodología indicada, el perfil medioambiental de una incineradora de RSU con recuperación de energía, con el fin de poder valorar el impacto ambiental de la instalación. Además se realiza una comparativa de la instalación con y sin recuperación energética para poder evaluar el impacto de dicho proceso. Por otra parte, se proponen mejoras y modificaciones tanto en los procesos como en los materiales utilizados de mayor impacto para reducir su contribución a los impactos medioambientales de la incineradora de RSU.

Activación alcalina para mezclas secas

44 p.

A SCR Model based on Reactor and Engine Experimental Studies for a Cu-zeolite Catalyst

A NOx reduction efficiency higher than 95% with NH3 slip less than 30 ppm is desirable for heavy-duty diesel (HDD) engines using selective catalytic reduction (SCR) systems to meet the US EPA 2010 NOx standard and the 2014-2018 fuel consumption regulation. The SCR performance needs to be improved through experimental and modeling studies. In this research, a high fidelity global kinetic 1-dimensional 2-site SCR model with mass transfer, heat transfer and global reaction mechanisms was developed for a Cu-zeolite catalyst. The model simulates the SCR performance for the engine exhaust conditions with NH3 maldistribution and aging effects, and the details are presented. SCR experimental data were collected for the model development, calibration and validation from a reactor at Oak Ridge National Laboratory (ORNL) and an engine experimental setup at Michigan Technological University (MTU) with a Cummins 2010 ISB engine. The model was calibrated separately to the reactor and engine data. The experimental setup, test procedures including a surrogate HD-FTP cycle developed for transient studies and the model calibration process are described. Differences in the model parameters were determined between the calibrations developed from the reactor and the engine data. It was determined that the SCR inlet NH3 maldistribution is one of the reasons causing the differences. The model calibrated to the engine data served as a basis for developing a reduced order SCR estimator model. The effect of the SCR inlet NO2/NOx ratio on the SCR performance was studied through simulations using the surrogate HD-FTP cycle. The cumulative outlet NOx and the overall NOx conversion efficiency of the cycle are highest with a NO2/NOx ratio of 0.5. The outlet NH3 is lowest for the NO2/NOx ratio greater than 0.6. A combined engine experimental and simulation study was performed to quantify the NH3 maldistribution at the SCR inlet and its effects on the SCR performance and kinetics. The uniformity index (UI) of the SCR inlet NH3 and NH3/NOx ratio (ANR) was determined to be below 0.8 for the production system. The UI was improved to 0.9 after installation of a swirl mixer into the SCR inlet cone. A multi-channel model was developed to simulate the maldistribution effects. The results showed that reducing the UI of the inlet ANR from 1.0 to 0.7 caused a 5-10% decrease in NOx reduction efficiency and 10-20 ppm increase in the NH3 slip. The simulations of the steady-state engine data with the multi-channel model showed that the NH3 maldistribution is a factor causing the differences in the calibrations developed from the engine and the reactor data. The Reactor experiments were performed at ORNL using a Spaci-IR technique to study the thermal aging effects. The test results showed that the thermal aging (at 800°C for 16 hours) caused a 30% reduction in the NH3 stored on the catalyst under NH3 saturation conditions and different axial concentration profiles under SCR reaction conditions. The kinetics analysis showed that the thermal aging caused a reduction in total NH3 storage capacity (94.6 compared to 138 gmol/m3), different NH3 adsorption/desorption properties and a decrease in activation energy and the pre-exponential factor for NH3 oxidation, standard and fast SCR reactions. Both reduction in the storage capability and the change in kinetics of the major reactions contributed to the change in the axial storage and concentration profiles observed from the experiments.

Boreal forest fire impacts on lower troposphere carbon monoxide and ozone levels at the regional to hemispheric scales

Tropospheric ozone (O3) and carbon monoxide (CO) pollution in the Northern Hemisphere is commonly thought to be of anthropogenic origin. While this is true in most cases, copious quantities of pollutants are emitted by fires in boreal regions, and the impact of these fires on CO has been shown to significantly exceed the impact of urban and industrial sources during large fire years. The impact of boreal fires on ozone is still poorly quantified, and large uncertainties exist in the estimates of the fire-released nitrogen oxides (NO x ), a critical factor in ozone production. As boreal fire activity is predicted to increase in the future due to its strong dependence on weather conditions, it is necessary to understand how these fires affect atmospheric composition. To determine the scale of boreal fire impacts on ozone and its precursors, this work combined statistical analysis of ground-based measurements downwind of fires, satellite data analysis, transport modeling and the results of chemical model simulations. The first part of this work focused on determining boreal fire impact on ozone levels downwind of fires, using analysis of observations in several-days-old fire plumes intercepted at the Pico Mountain station (Azores). The results of this study revealed that fires significantly increase midlatitude summertime ozone background during high fire years, implying that predicted future increases in boreal wildfires may affect ozone levels over large regions in the Northern Hemisphere. To improve current estimates of NOx emissions from boreal fires, we further analyzed ΔNOy /ΔCO enhancement ratios in the observed fire plumes together with transport modeling of fire emission estimates. The results of this analysis revealed the presence of a considerable seasonal trend in the fire NOx /CO emission ratio due to the late-summer changes in burning properties. This finding implies that the constant NOx /CO emission ratio currently used in atmospheric modeling is unrealistic, and is likely to introduce a significant bias in the estimated ozone production. Finally, satellite observations were used to determine the impact of fires on atmospheric burdens of nitrogen dioxide (NO2 ) and formaldehyde (HCHO) in the North American boreal region. This analysis demonstrated that fires dominated the HCHO burden over the fires and in plumes up to two days old. This finding provides insights into the magnitude of secondary HCHO production and further enhances scientific understanding of the atmospheric impacts of boreal fires.

MODELING AND EXPERIMENTAL SETUP OF AN HCCI ENGINE

For the past three decades the automotive industry is facing two main conflicting challenges to improve fuel economy and meet emissions standards. This has driven the engineers and researchers around the world to develop engines and powertrain which can meet these two daunting challenges. Focusing on the internal combustion engines there are very few options to enhance their performance beyond the current standards without increasing the price considerably. The Homogeneous Charge Compression Ignition (HCCI) engine technology is one of the combustion techniques which has the potential to partially meet the current critical challenges including CAFE standards and stringent EPA emissions standards. HCCI works on very lean mixtures compared to current SI engines, resulting in very low combustion temperatures and ultra-low NOx emissions. These engines when controlled accurately result in ultra-low soot formation. On the other hand HCCI engines face a problem of high unburnt hydrocarbon and carbon monoxide emissions. This technology also faces acute combustion controls problem, which if not dealt properly with yields highly unfavorable operating conditions and exhaust emissions. This thesis contains two main parts. One part deals in developing an HCCI experimental setup and the other focusses on developing a grey box modelling technique to control HCCI exhaust gas emissions. The experimental part gives the complete details on modification made on the stock engine to run in HCCI mode. This part also comprises details and specifications of all the sensors, actuators and other auxiliary parts attached to the conventional SI engine in order to run and monitor the engine in SI mode and future SI-HCCI mode switching studies. In the latter part around 600 data points from two different HCCI setups for two different engines are studied. A grey-box model for emission prediction is developed. The grey box model is trained with the use of 75% data and the remaining data is used for validation purpose. An average of 70% increase in accuracy for predicting engine performance is found while using the grey-box over an empirical (black box) model during this study. The grey-box model provides a solution for the difficulty faced for real time control of an HCCI engine. The grey-box model in this thesis is the first study in literature to develop a control oriented model for predicting HCCI engine emissions for control.

DYNAMIC MODEL BASED STATE ESTIMATION IN A HEAVY DUTY DIESEL AFTERTREATMENT SYSTEM FOR ONBOARD DIAGNOSTICS AND CONTROLS

Estimating un-measurable states is an important component for onboard diagnostics (OBD) and control strategy development in diesel exhaust aftertreatment systems. This research focuses on the development of an Extended Kalman Filter (EKF) based state estimator for two of the main components in a diesel engine aftertreatment system: the Diesel Oxidation Catalyst (DOC) and the Selective Catalytic Reduction (SCR) catalyst. One of the key areas of interest is the performance of these estimators when the catalyzed particulate filter (CPF) is being actively regenerated. In this study, model reduction techniques were developed and used to develop reduced order models from the 1D models used to simulate the DOC and SCR. As a result of order reduction, the number of states in the estimator is reduced from 12 to 1 per element for the DOC and 12 to 2 per element for the SCR. The reduced order models were simulated on the experimental data and compared to the high fidelity model and the experimental data. The results show that the effect of eliminating the heat transfer and mass transfer coefficients are not significant on the performance of the reduced order models. This is shown by an insignificant change in the kinetic parameters between the reduced order and 1D model for simulating the experimental data. An EKF based estimator to estimate the internal states of the DOC and SCR was developed. The DOC and SCR estimators were simulated on the experimental data to show that the estimator provides improved estimation of states compared to a reduced order model. The results showed that using the temperature measurement at the DOC outlet improved the estimates of the CO , NO , NO2 and HC concentrations from the DOC. The SCR estimator was used to evaluate the effect of NH3 and NOX sensors on state estimation quality. Three sensor combinations of NOX sensor only, NH3 sensor only and both NOX and NH3 sensors were evaluated. The NOX only configuration had the worst performance, the NH3 sensor only configuration was in the middle and both the NOX and NH3 sensor combination provided the best performance.

Free Troposphere Ozone and Carbon Monoxide over the North Atlantic for 2001-2011

Carbon Monoxide (CO) and Ozone (O3) are considered to be one of the most important atmospheric pollutants in the troposphere with both having significant effects on human health. Both are included in the U.S. E.P.A list of criteria pollutants. CO is primarily emitted in the source region whereas O3 can be formed near the source, during transport of the pollution plumes containing O3 precursors or in a receptor region as the plumes subside. The long chemical lifetimes of both CO and O3 enable them to be transported over long distances. This transport is important on continental scales as well, commonly referred to as inter-continental transport and affects the concentrations of both CO and O3 in downwind receptor regions, thereby having significant implications for their air quality standards. Over the period 2001-2011, there have been decreases in the anthropogenic emissions of CO and NOx in North America and Europe whereas the emissions over Asia have increased. How these emission trends have affected concentrations at remote sites located downwind of these continents is an important question. The PICO-NARE observatory located on the Pico Mountain in Azores, Portugal is frequently impacted by North American pollution outflow (both anthropogenic and biomass burning) and is a unique site to investigate long range transport from North America. This study uses in-situ observations of CO and O3 for the period 2001-2011 at PICO-NARE coupled with output from the full chemistry (with normal and fixed anthropogenic emissions) and tagged CO simulations in GEOS-Chem, a global 3-D chemical transport model of atmospheric composition driven by meteorological input from the Goddard Earth Observing System (GEOS) of the NASA Global Modeling and Assimilation Office, to determine and interpret the trends in CO and O3 concentrations over the past decade. These trends would be useful in ascertaining the impacts emission reductions in the United States have had over Pico and in general over the North Atlantic. A regression model with sinusoidal functions and a linear trend term was fit to the in-situ observations and the GEOS-Chem output for CO and O3 at Pico respectively. The regression model yielded decreasing trends for CO and O3 with the observations (-0.314 ppbv/year & -0.208 ppbv/year respectively) and the full chemistry simulation with normal emissions (-0.343 ppbv/year & -0.526 ppbv/year respectively). Based on analysis of the results from the full chemistry simulation with fixed anthropogenic emissions and the tagged CO simulation it was concluded that the decreasing trends in CO were a consequence of the anthropogenic emission changes in regions such as USA and Asia. The emission reductions in USA are countered by Asian increases but the former have a greater impact resulting in decreasing trends for CO at PICO-NARE. For O3 however, it is the increase in water vapor content (which increases O3 destruction) along the pathways of transport from North America to PICO-NARE as well as around the site that has resulted in decreasing trends over this period. This decrease is offset by increase in O3 concentrations due to anthropogenic influence which could be due to increasing Asian emissions of O3 precursors as these emissions have decreased over the US. However, the anthropogenic influence does not change the final direction of the trend. It can thus be concluded that CO and O3 concentrations at PICO-NARE have decreased over 2001-2011.

AN INVESTIGATION OF VARIABLE VALVE TIMING EFFECTS ON HCCI ENGINE PERFORMANCE

The Homogeneous Charge Compression Ignition (HCCI) engine is a promising combustion concept for reducing NOx and particulate matter (PM) emissions and providing a high thermal efficiency in internal combustion engines. This concept though has limitations in the areas of combustion control and achieving stable combustion at high loads. For HCCI to be a viable option for on-road vehicles, further understanding of its combustion phenomenon and its control are essential. Thus, this thesis has a focus on both the experimental setup of an HCCI engine at Michigan Technological University (MTU) and also developing a physical numerical simulation model called the Sequential Model for Residual Affected HCCI (SMRH) to investigate performance of HCCI engines. The primary focus is on understanding the effects of intake and exhaust valve timings on HCCI combustion. For the experimental studies, this thesis provided the contributions for development of HCCI setup at MTU. In particular, this thesis made contributions in the areas of measurement of valve profiles, measurement of piston to valve contact clearance for procuring new pistons for further studies of high geometric compression ratio HCCI engines. It also consists of developing and testing a supercharging station and the setup of an electrical air heater to extend the HCCI operating region. The HCCI engine setup is based on a GM 2.0 L LHU Gen 1 engine which is a direct injected engine with variable valve timing (VVT) capabilities. For the simulation studies, a computationally efficient modeling platform has been developed and validated against experimental data from a single cylinder HCCI engine. In-cylinder pressure trace, combustion phasing (CA10, CA50, BD) and performance metrics IMEP, thermal efficiency, and CO emission are found to be in good agreement with experimental data for different operating conditions. Effects of phasing intake and exhaust valves are analyzed using SMRH. In addition, a novel index called Fuel Efficiency and Emissions (FEE) index is defined and is used to determine the optimal valve timings for engine operation through the use of FEE contour maps.

Analisi delle problematiche ambientali dello stabilimento siderurgico ILVA e parziale valutazione dell’impatto delle sue emissioni in atmosfera attraverso il modello CALPUFF

Il presente lavoro di tesi riguarda lo studio di un modello di stima delle emissioni per la previsione della contaminazione ambientale in aria. Il lavoro è stato svolto all’interno del DICAM dell’Università di Bologna attraverso il supporto del relatore Giacomo Antonioni e dei correlatori Ada Saracino e Gigliola Spadoni. L’applicazione modellistica, attraverso l’uso del software CALPUFF, ha trattato le emissioni del camino E312 della sezione Agglomerazione dello stabilimento siderurgico ILVA di Taranto nell’anno 2015. Gli inquinanti simulati sono quelli per i quali lo SME fornisce il flusso di massa: SO2, NOx, PM. Le polveri sono state considerate completamente costituite da polveri PM10 e per esse si è calcolata la concentrazione al suolo e la deposizione. A partire dai risultati per le polveri, ipotizzando che siano in parte veicolati da esse, sono state valutate anche le concentrazioni e le deposizioni di Diossine. Della configurazione modellistica “ottimale” sono stati presentati: ▪ Per i macroinquinanti le medie annue di concentrazione al suolo, e quindi, la dispersione degli inquinanti. ▪ Per i microinquinanti i valori massimi di concentrazione annua e di deposizione ottenuti nell’area di studio. Nel caso in esame, lo studio è stato riferito alla rete deposimetrica di gestione ILVA (per mancanza di dati deposimetrici della rete di gestione ARPA). In particolare è stato preso in considerazione il deposimetro del quartiere Tamburi a fronte delle criticità rilevate nei mesi di Novembre 2014 e Febbraio 2015, tale per cui, visti gli elevatissimi valori di deposizione, vista la notevole importanza che i dati deposimetrici hanno rispetto al rischio sanitario per ingestione, è stata aperta un’indagine della procura che ha affidato l’analisi a ARPA PUGLIA congiunta con l’ISPRA (che ne ha mandato ministeriale) e la Regione Puglia. A fronte di tali episodi, il seguente studio ha voluto fornire un resoconto deposimetrico per l’anno 2015.

'El futuro' del español como lengua segunda y extranjera

La enseñanza y aprendizaje de la gramática de la lengua española como lengua segunda y extranjera es un proceso altamente complejo, cuyas aristas debería incluir la variación para que tanto estudiosos del tema, escritores de material bibliográfico, docentes como alumnos contáramos con una herramienta facilitadora y, pensamos, eficaz, para su abordaje y para un empleo funcional en búsqueda del acto comunicativo exitoso (Searle, 1986). Por esta razón compartimos una línea de investigación que se desprende de la tesis en etapa de desarrollo de la maestría de UBA en Análisis del Discurso titulada ?El futuro de los políticos. Un estudio de la variación morfosintáctica en el empleo de los tiempos de futuro en el discurso político? dirigida por la Doctora Angelita Martínez. Se trata de un estudio de variación etnopragmático(García, E. 1995; Martínez, A. 1995) que sigue los principios de la Escuela de Columbia (Contini Morava, 1995; Diver, 1995; Reid, 2004) sobre las formas morfosintácticas de futuro en el español rioplatense de los políticos de la actualidad. Con un corpus de 161 emisiones de futuro sintáctico (FS) y futuro perifrástico(FP) nos proponemos probar si el factor de la edad del orador político ejerce influencia en la selección o no. Según los significados básicos de las formas, los gramáticos de todos los tiempos han coincidido en que cuando los hablantes quieren expresar certeza optan por el FP mientras que el FS expresa mayor lejanía, y por ende, menor certeza. Sin embargo, en el discurso de los políticos argentinos con frecuencia se observa el empleo del FS, y no pensamos que éstos quieran comunicar incerteza de sus dichos ni promesa, sino, postulamos, que hacen uso de esta forma para expresar la acción futura como algo que inevitablemente ocurrirá, más allá de posibilidad de manipulación o incidencia, casi como una profecía, y que dejan el FP para expresar la posibilidad de manipulación sobre esos hechos futuros (Martínez & Mailhes, 2012; Mailhes, 2011, 2012a,b,c, 2014)

'El futuro' del español como lengua segunda y extranjera

La enseñanza y aprendizaje de la gramática de la lengua española como lengua segunda y extranjera es un proceso altamente complejo, cuyas aristas debería incluir la variación para que tanto estudiosos del tema, escritores de material bibliográfico, docentes como alumnos contáramos con una herramienta facilitadora y, pensamos, eficaz, para su abordaje y para un empleo funcional en búsqueda del acto comunicativo exitoso (Searle, 1986). Por esta razón compartimos una línea de investigación que se desprende de la tesis en etapa de desarrollo de la maestría de UBA en Análisis del Discurso titulada ?El futuro de los políticos. Un estudio de la variación morfosintáctica en el empleo de los tiempos de futuro en el discurso político? dirigida por la Doctora Angelita Martínez. Se trata de un estudio de variación etnopragmático(García, E. 1995; Martínez, A. 1995) que sigue los principios de la Escuela de Columbia (Contini Morava, 1995; Diver, 1995; Reid, 2004) sobre las formas morfosintácticas de futuro en el español rioplatense de los políticos de la actualidad. Con un corpus de 161 emisiones de futuro sintáctico (FS) y futuro perifrástico(FP) nos proponemos probar si el factor de la edad del orador político ejerce influencia en la selección o no. Según los significados básicos de las formas, los gramáticos de todos los tiempos han coincidido en que cuando los hablantes quieren expresar certeza optan por el FP mientras que el FS expresa mayor lejanía, y por ende, menor certeza. Sin embargo, en el discurso de los políticos argentinos con frecuencia se observa el empleo del FS, y no pensamos que éstos quieran comunicar incerteza de sus dichos ni promesa, sino, postulamos, que hacen uso de esta forma para expresar la acción futura como algo que inevitablemente ocurrirá, más allá de posibilidad de manipulación o incidencia, casi como una profecía, y que dejan el FP para expresar la posibilidad de manipulación sobre esos hechos futuros (Martínez & Mailhes, 2012; Mailhes, 2011, 2012a,b,c, 2014)