Thèses : « Emissions of pollutant »

1

Gonçalves, Cátia Vanessa Maio. « Contribution of biomass combustion to air pollutant emissions ». Doctoral thesis, Universidade de Aveiro, 2011. http://hdl.handle.net/10773/8104.

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Doutoramento em Ciências e Engenharia do Ambiente
In Portugal, it was estimated that around 1.95 Mton/year of wood is used in residential wood burning for heating and cooking. Additionally, in the last decades, burnt forest area has also been increasing. These combustions result in high levels of toxic air pollutants and a large perturbation of atmospheric chemistry, interfere with climate and have adverse effects on health. Accurate quantification of the amounts of trace gases and particulate matter emitted from residential wood burning, agriculture and garden waste burning and forest fires on a regional and global basis is essential for various purposes, including: the investigation of several atmospheric processes, the reporting of greenhouse gas emissions, and quantification of the air pollution sources that affect human health at regional scales. In Southern Europe, data on detailed emission factors from biomass burning are rather inexistent. Emission inventories and source apportionment, photochemical and climate change models use default values obtained for US and Northern Europe biofuels. Thus, it is desirable to use more specific locally available data. The objective of this study is to characterise and quantify the contribution of biomass combustion sources to atmospheric trace gases and aerosol concentrations more representative of the national reality. Laboratory (residential wood combustion) and field (agriculture/garden waste burning and experimental wildland fires) sampling experiments were carried out. In the laboratory, after the selection of the most representative wood species and combustion equipment in Portugal, a sampling program to determine gaseous and particulate matter emission rates was set up, including organic and inorganic aerosol composition. In the field, the smoke plumes from agriculture/garden waste and experimental wildland fires were sampled. The results of this study show that the combustion equipment and biofuel type used have an important role in the emission levels and composition. Significant differences between the use of traditional combustion equipment versus modern equipments were also observed. These differences are due to higher combustion efficiency of modern equipment, reflecting the smallest amount of particulate matter, organic carbon and carbon monoxide released. With regard to experimental wildland fires in shrub dominated areas, it was observed that the largest organic fraction in the samples studied was mainly composed by vegetation pyrolysis products. The major organic components in the smoke samples were pyrolysates of vegetation cuticles, mainly comprising steradienes and sterol derivatives, carbohydrates from the breakdown of cellulose, aliphatic lipids from vegetation waxes and methoxyphenols from the lignin thermal degradation. Despite being a banned practice in our country, agriculture/garden waste burning is actually quite common. To assess the particulate matter composition, the smoke from three different agriculture/garden residues have been sampled into 3 different size fractions (PM2.5, PM2.5-10 and PM>10). Despite distribution patterns of organic compounds in particulate matter varied among residues, the amounts of phenolics (polyphenol and guaiacyl derivatives) and organic acids were always predominant over other organic compounds in the organosoluble fraction of smoke. Among biomarkers, levoglucosan, β-sitosterol and phytol were detected in appreciable amounts in the smoke of all agriculture/garden residues. In addition, inositol may be considered as an eventual tracer for the smoke from potato haulm burning. It was shown that the prevailing ambient conditions (such as high humidity in the atmosphere) likely contributed to atmospheric processes (e.g. coagulation and hygroscopic growth), which influenced the particle size characteristics of the smoke tracers, shifting their distribution to larger diameters. An assessment of household biomass consumption was also made through a national scale survey. The information obtained with the survey combined with the databases on emission factors from the laboratory and field tests allowed us to estimate the pollutant amounts emitted in each Portuguese district. In addition to a likely contribution to the improvement of emission inventories, emission factors obtained for tracer compounds in this study can be applied in receptor models to assess the contribution of biomass burning to the levels of atmospheric aerosols and their constituents obtained in monitoring campaigns in Mediterranean Europe.
Em Portugal, estima-se que 1.95 Mton/ano de lenha sejam utilizadas na queima doméstica para aquecimento e confecção de alimentos. Em simultâneo, nas últimas décadas, a área de floresta ardida também tem vindo a aumentar. Estes tipos de combustão contribuem para a libertação de quantidades elevadas de poluentes tóxicos que perturbam a química da atmosfera, interferem com o clima e possuem efeitos nefastos na saúde. A quantificação rigorosa, à escala regional e global, das emissões de gases e matéria particulada associada à queima doméstica, queima de resíduos agrícolas e fogos florestais é fundamental para vários fins, nomeadamente na investigação dos diversos processos atmosféricos, na elaboração de relatórios de emissões de gases de estufa, e na quantificação de fontes de poluição atmosférica que afectam a saúde humana. No sul da Europa, as bases de dados com factores de emissão detalhados são praticamente inexistentes. Os modelos climáticos, a modelização fotoquímica, os inventários de emissões e os estudos de identificação de fontes emissoras utilizam valores típicos obtidos para biomassa norte-americana ou do norte da Europa. Assim, é conveniente utilizar valores mais específicos obtidos localmente. Este estudo teve como principal objectivo a caracterização e quantificação dos gases e aerossóis emitidos por fontes de queima de biomassa, englobando as espécies lenhosas mais representativas da realidade nacional. Foram realizadas experiências de amostragem em laboratório (queima doméstica) e no campo (queima de resíduos agrícolas/jardim e fogos florestais controlados). Em laboratório, após selecção das espécies de biomassa e dos equipamentos de queima mais representativos em Portugal, estabeleceu-se um programa de amostragem para determinar os factores de emissão de poluentes gasosos e particulados, incluindo a composição orgânica e inorgânica dos aerossóis. Ao nível do campo, efectuou-se a amostragem das plumas de fumo resultantes da queima de resíduos agrícolas/jardim e de fogos controlados numa área dominada por espécies arbustivas. Os resultados deste estudo mostram que o tipo de equipamento de combustão e o tipo de biomassa utilizados têm um papel importante nos níveis e composição dos poluentes emitidos. Diferenças significativas entre o uso de equipamentos de combustão tradicionais versus equipamentos modernos foram observadas. Estas diferenças devem-se à maior eficiência de combustão dos equipamentos modernos, reflectindo-se na menor quantidade de matéria particulada, carbono orgânico e monóxido de carbono libertados. No que diz respeito ao fogo controlado em áreas dominadas por espécies arbustivas observou-se que a fracção orgânica estudada nas amostras de fumo é composta essencialmente por produtos resultantes da pirólise da vegetação. Estes produtos são constituídos na sua maioria por esteredienos e derivados de esteróis, hidratos de carbono resultantes da quebra das moléculas de celulose, produtos alifáticos provenientes de ceras vegetais e metoxifenóis resultantes da degradação térmica da lenhina. A queima de resíduos agrícolas e de jardim, apesar de ser uma prática proibida no nosso país, é uma realidade bastante frequente. Para avaliar a composição das emissões de alguns tipos de resíduos foram recolhidas amostras de três tamanhos diferentes (PM2.5, PM2.5-10 and PM>10). Apesar de se poder observar uma grande variabilidade em termos de compostos orgânicos dependendo do tipo de resíduo queimado, os compostos fenólicos (derivados do polifenol e guaiacil) e os ácidos orgânicos foram sempre predominantes em relação à restante fracção orgânica. O levoglucosano, o β-sitosterol e o fitol foram os traçadores de queima de biomassa detectados em quantidades mais apreciáveis na generalidade dos resíduos agrícolas e de jardim. O inositol pode ser considerado um bom traçador para as emissões resultantes da queima de rama de batata. Observou-se que as condições ambientais (tais como valores elevados de humidade relativa na atmosfera) provavelmente contribuíram para processos de coagulação e de crescimento higroscópico que influenciaram as características dos traçadores de biomassa, mudando sua distribuição para diâmetros maiores. Foi também feita a avaliação do consumo doméstico de biomassa na forma de um inquérito aplicado à escala nacional. Os resultados obtidos, conjugados com as bases de dados sobre factores de emissão obtidas nos ensaios de queima laboratoriais, permitiram estimar as quantidades emitidas de vários poluentes em cada distrito de Portugal continental. Além de contribuir significativamente para o aperfeiçoamento dos inventários de emissões, os factores de emissão obtidos para vários compostos traçadores poderão ser aplicados em modelos no receptor de forma a avaliar a contribuição da queima de biomassa para os níveis de aerossóis atmosféricas e seus constituintes obtidos em campanhas de monitorização na Europa mediterrânea.

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Rayfield, David. « Estimation of road traffic pollutant emissions in Greater Manchester ». Thesis, Manchester Metropolitan University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364058.

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Kassinis, Georgios Ioannis. « Towards an improved procedure for estimating industrial-pollutant emissions ». Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/67413.

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Franco, García Vicente. « Evaluation and improvement of road vehicle pollutant emission factors based on instantaneous emissions data processing ». Doctoral thesis, Universitat Jaume I, 2014. http://hdl.handle.net/10803/146187.

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Introduction
Current instrumentation makes it possible to measure vehicle emissions with high temporal resolution. But the increased resolution of emissions signals does not equate with increased accuracy. A prerequisite for the derivation of accurate emission factors from instantaneous vehicle emissions data is a fine allocation of measured mass emissions to recorded engine or vehicle states. This poses a technical challenge, because vehicle emission test facilities are not designed to support instantaneous emissions modelling, and they introduce distorting effects that compromise the instantaneous accuracy of the measured signals.

Methodology
These distorting effects can be compensated through a combination of physical modelling and data post-processing. The main original contribution of this dissertation is a novel methodology for the compensation of instantaneous emission signals, which is fully described herein. Whereas previous methodologies relied on systems theory modelling, and on comprehensive testing to model the sub-systems of the measurement setup, the alternative approach uses CO2 as a tracer of the distortions brought about by the measurement setup, which is modelled as a 'lump' system.

Conclusions
The main benefits of this methodology are its low burden of experimental work and its flexibility. Furthermore, it has been fully implemented in the 'esto' software tool, which can perform the compensation of emission signals with minimal user intervention and speed up the creation of engine emission maps.

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Ogunlaja, Olumuyiwa Omotola. « Measurement of Air Pollutant Emissions from a Confined Poultry Facility ». DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/392.

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Air emissions from animal feeding operations have become a growing concern. Much work has been done to study occupational exposures and the exhaust concentrations associated with animal facilities; however little information has been provided about air quality around the houses. Ammonia (NH3 ), ethanol (EtOH), nitrous oxide (N2O), carbon dioxide (CO2), and particulate matter (PM 2.5 and PM10) emissions were monitored in two different buildings for laying hens in northern Utah. Over the six-month sampling period, the observed average temperatures for the west and east fan banks of the high-rise building were 21.2±4 and 19.4±1.3°C, respectively, and the average inside relative humidities during the same period were 43.7±7.2 and 48.4±7.9%, respectively. Furthermore, the observed average temperatures for the west and east fan banks of the manure-belt building were 20.6±4.4 and 17.9±2.7°C, respectively, and the average percent inside relative humidities during the same period were 44.4 ±7.6 and 49.3±7.4%, respectively. The ventilation rates ranged from 0.80 m3 h-1 bird-1 to 4.80 m3 h-1 bird -1 with an average of 2.02 m3 h -1 bird -1 for the high-rise barn and from 0.80 m3 h-1 bird -1 to 6.0 m3 h-1 bird-1 with an average of 2.20 m3 h-1 bird-1 for the manure-belt building over the sampling period of September, October, November, and December 2008 and January 2009. Average NH3 emission factors were 72±17 g d-1 AU-1 for the high-rise system and 9.1±7 g d-1 AU-1 for the manure-belt (1 AU is equal to 500 kg of animal live weight). The NH3 emission reduction factor for the manure-belt technique compared to the high-rise technique was 87%. Ammonia levels outside the house appeared to be less than 1 ppm. No significant emissions were registered for N2O, H2S, and EtOH, which were consistently close to zero for both techniques. The carbon dioxide (CO2) emission factor from the high-rise building was 104±11 g day-1 AU-1 and from the manure-belt building, 105±20 g day-1 AU-1. PM emissions were greater from the manure-belt system in comparison with the high-rise system, showing mean values of 165 vs. 114 g day-1 AU-1 for PM 2.5, 1,987 vs. 1,863 g day-1 AU-1for PM10 and 4,460 vs. 3,462 g day-1 AU-1 for TSP respectively. None of the 24-h PM 2.5 measurements collected from both management techniques exceeded the U.S. EPA 24-hr National Ambient Air Quality Standard (NAAQS) of 35 μg/m 3.

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Upton, Nigel Keith. « Algorithmic solution of air-pollutant cloud models ». Thesis, Cranfield University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304572.

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Graville, Stephen Rhys. « Pollutant formation during the combustion of heavy liquid fuels ». Thesis, University College London (University of London), 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262602.

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Sakhrieh, Ahmad Hasan. « Reduction of pollutant emissions from high pressure flames using an electric field ». Erlangen ESYTEC, Energie- und Systemtechnik GmbH, 2006. http://deposit.d-nb.de/cgi-bin/dokserv?id=2959665&prov=M&dok_var=1&dok_ext=htm.

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Taylor, David. « Assessment of policies to reduce pollutant emissions from European Community freight transport ». Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246084.

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Mashio, Tomoka 1973. « A study of ground-level air pollutant emissions from airport mobile sources ». Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/80650.

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North, Robin J. « Assessment of real-world pollutant emissions from a light-duty diesel vehicle ». Thesis, Imperial College London, 2007. http://hdl.handle.net/10044/1/1288.

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One of the major issues in road transport today is poor air quality and the associated negative health impacts. In particular, diesel vehicles are found to contribute substantially to atmospheric levels of particulate matter (PM) and ozone (O3). Pollutant mass emission rates from motor vehicles vary greatly according to their operating mode. Consequently, changes in road layout or traffic behaviour may have a significant impact on local air quality. Improved understanding of the underlying emission mechanisms can help at the traffic planning stage in order to assess environmental impacts and aid in the design of more efficient air quality management methods. However, existing planning tools do not adequately represent the variable and transient nature of pollutant emission rates from vehicles, especially with regard to emissions of PM. This thesis addresses the issue of how motor vehicles, and in particular, light-duty diesel vehicles contribute to local air pollution. It does so with reference to a series of experiments conducted with a 1999 model-year Ford Focus turbo-diesel test vehicle. The vehicle was equipped with an on-board monitoring system developed and validated for this research to address the shortcomings of existing devices. The resultant data are used to examine the second-by-second mass emission rates of pollutant species, including PM. The extension of an existing instantaneous model for gaseous pollutants to represent PM emissions is then examined, with an adjustment to the model structure found to improve emission estimates. The experimental techniques developed in this thesis are compared to reference data obtained using a chassis dynamometer emissions test facility. The models are compared to the on-board measurements for both laboratory and on-road tests. These comparisons show that on-board monitoring offers a more precise representation of the pollutant mass emission rates than the modelling techniques considered. Nevertheless, the model performance is sufficiently good to suggest that realistic estimates may be obtained through the simulation of vehicle trajectories and the associated pollutant emission rates. Importantly, the techniques developed in this research are able to replicate the high-emission episodes associated with transient vehicle operation. This offers the possibility to assess the impact of traffic management schemes on PM emission levels more accurately than has previously been possible.

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Moore, Kori D. « Measurement of Agriculture-Related Air Pollutant Emissions using Point and Remote Sensors ». DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/6907.

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Measuring air pollution emissions from agricultural activities is usually difficult because of their large area and variability. Traditional air quality sensors, called point samplers, measure conditions in one location, which may not adequately measure a plume. Remote sensors, instruments that measure pollution along a line rather than at a single point, are better able to measure conditions around large areas. This dissertation reports on four agricultural air emissions studies that used both point and remote sensors for comparison. The methods used to calculate the emissions are based on previous work and are further developed in these studies. In particular, an atmospheric dispersion model was developed and tested that can account for a particle behaving different than the surrounding gas due to gravity and inertia and depositing out of the flow. Particulate matter (PM) emissions values are reported for two agricultural tillage conservation management practices (CMPs)and the corresponding traditional tillage methods in order to determine how well the CMP reduces emissions. In addition, gas-phase ammonia (NH3) emissions for a dairy operation and PM emissions from a feedlot operation are reported. These studies can help us better measure emissions from agricultural operations and understand how much air pollution is being emitted.

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Linaritakis, Konstantinos N. « Factors affecting traffic-related air pollutant levels in urban streets ». Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47154.

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Rodríguez, Juan Felipe. « Investigations on the pollutant emissions of gasoline direct injection engines during cold-start ». Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104130.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 200-208).
As the CO2 emission standards around the world become more stringent, the turbocharged downsized gasoline direct injection (GDI) engine provides a mature platform to achieve better fuel economy. For this reason, it is expected that the GDI engine will capture increasing shares of the market during the coming years. The in-cylinder liquid injection, though advantageous in most engine operation regimes, creates emissions challenges during the cold crank-start and cold fast-idle phases. The engine cold-start is responsible for a disproportionate share of the hydrocarbons (HC), nitrogen oxides (NOx) and particulate matter (PM) emitted over the certification cycle. Understanding the sources of the pollutants during this stage is necessary for the further market penetration of GDI under the constraint of tighter emission standards. This work aims to examine the formation processes of the HC, NOx and PM emissions during the cold-start phase in a GDI engine, and the sensitivity of the pollutant emissions to different operation strategies. To this end, a detailed analysis of the crank-start was carried out, in which the first three engine cycles were individually examined. For the steady-state phase, the trade-off between low fast-idle emissions and high exhaust thermal enthalpy flow, necessary for fast catalyst warm-up, is investigated under several operation strategies. The pollutant formation processes are strongly dependent on the mixture formation and on the temperature and pressure history of the combustion process. The results show that unconventional valve timing strategies with large, symmetric, negative valve overlap and delayed combustion phasing are the most effective ways to reduce engine-out emissions during both crank-start and fast-idle phases.
by Juan Felipe Rodríguez.
Ph. D.

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Thorning, Peter James. « Community Knowledge and Use of the National Pollutant Inventory ». Thesis, Griffith University, 2009. http://hdl.handle.net/10072/380711.

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Pollutant Release and Transfer Registers (PRTRs) have been established in many countries on the basis, at least partially, that community awareness will lead to pressure on polluters to reduce their emissions. In Australia, the National Pollutant Inventory (NPI) was established to fulfil this role amongst others. The success of the NPI depends on the extent of engagement that the general population and pro-environment community groups have with the program. This research aims to determine the extent of knowledge and use of the NPI that exists in the community, and to identify whether barriers exist which indicate a need to restructure aspects of the program to overcome these barriers. Surveys were conducted of the general population in Queensland, using a mail-out questionnaire with randomly selected participants, and pro-environment community groups in Australia, using a mail-out survey with purposeful selection of participants, to obtain information about the knowledge and use of the NPI and to identify barriers to that knowledge and use. Data was analysed from 609 completed general population surveys, 78 completed pro-environment community group surveys completed in 2007 and the results compared to 47 pro-environment community group surveys from a survey that had previously been conducted in 2001. It was determined that almost 23% of the general population have sufficient awareness to be able to obtain information from the NPI website should they wish to do so. Lower levels of specific knowledge were found, which was comparable to previous studies. These results were also similar to studies of community knowledge of the Toxics Release Inventory (TRI) in the United States. The level of awareness of the NPI among green groups (that is, nature conservation focussed environment groups) was determined to be just over 51% and the awareness among brown groups (that is, industrial or pollution focussed environment groups) was determined to be almost 76%. The general population carried out limited searches of the website and made limited use of the available information. Members of brown groups were most active in accessing the information and then making use of it, although even among this group use of the information was limited. The main barrier to knowledge and use of the NPI was lack of promotion and awareness raising activities. This has significant implications for the program, identifying a need to establish an effective communication strategy that promotes the NPI website and encourages active participation.
Thesis (Masters)
Master of Science (MSc)
School of Environment and Sc
Science, Environment, Engineering and Technology
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Kwong, Chi Wai. « Effect of co-combustion of coal and biomass on combustion performance and pollutant emissions / ». View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?MECH%202005%20KWONG.

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Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005.
"Sponsored by: CLP Research Institute." "HKUST project no.: CLPRI02/03.EG01." Includes bibliographical references (leaves 76-83). Also available in electronic version.

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Horne, Vincent Howard. « The use of artificial neural networks for the prediction of pollutant emissions from aeroengines ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0034/MQ65856.pdf.

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Darnton, Nicholas Julian. « Fuel consumption and pollutant emissions of spark ignition engines during cold-started drive cycles ». Thesis, University of Nottingham, 1997. http://eprints.nottingham.ac.uk/13250/.

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This thesis details the development and evaluation of a procedure to predict the fuel consumption and pollutant emissions of spark ignition engines during cold-started drive cycles. Such predictions are of use in the early development and optimisation of an engine and vehicle combination with regard to legislated limits on vehicle performance over defined drive cycles. Although levels of pollutant emissions are the main focus of legislation, reducing fuel consumption is also of interest and drive cycle fuel consumption figures provide a useful benchmark of vehicle performance appraisals. The procedure makes use of a combination of engine friction models and experimentally defined correction functions to enable the application of fully-warm engine test bed data to cold-start conditions. This accounts for the effects of engine temperature on friction levels, mixture preparation and start-up transient behaviour. Experimental data to support the models and assumptions used are presented and discussed. Although not an essential part of the procedure, neural networks have been used to characterise the fully-warm engine mapping data. These are shown to provide an effective way of interpolating between engine mapping points. To facilitate the prediction of tail-pipe emissions, a simple catalyst efficiency model has been included and the complete procedure incorporated into a single software package enabling second-by-second fuel and emissions flow rates to be predicted for a given engine and vehicle combination over a defined drive cycle. This package is called CECSP or the Cold Emissions Cycle Simulation Program. The program has been designed to run on PC machines. The procedure has been validated by application to a typical 1.8 litre medium sized vehicle driven over the ECE+EUDC drive cycle and the predictions found to be within the target accuracy of +/-5% for fuel consumption and +/-10% for engine-out emissions. Envisaged applications of the procedure to rank the sources of increased fuel consumption and emissions due to cold-starting and engine and vehicle details are outlined.

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Belton, Christopher. « Fuel behaviour and pollutant emissions during the cold operation of a spark ignition engine ». Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365108.

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Yates, Anthony John. « LCA, clean-up technologies and abatement of gaseous pollutant emissions from chemical processing plant ». Thesis, University of Surrey, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388784.

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Klapmeyer, Michael Evan. « Characterization of Urban Air Pollutant Emissions by Eddy Covariance using a Mobile Flux Laboratory ». Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/37675.

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Air quality management strategies in the US are developed largely from estimates of emissions, some highly uncertain, rather than actual measurements. Improved knowledge based on measurements of real-world emissions is needed to increase the effectiveness of these strategies. Consequently, the objectives of this research were to (1) quantify relationships among urban emissions sources, land use, and demographics, (2) determine the spatial and temporal variability of emissions, and (3) evaluate the accuracy of official emissions estimates. These objectives guided three field campaigns that employed a unique mobile laboratory equipped to measure pollutant fluxes by eddy covariance. The first campaign, conducted in Norfolk, Virginia, represented the first time fluxes of nitrogen oxides (NOx) were measured by eddy covariance in an urban environment. Fluxes agreed to within 10% of estimates in the National Emissions Inventory (NEI), but were three times higher than those of an inventory used for air quality modeling and planning. Additionally, measured fluxes were correlated with road density and increased development. The second campaign took place in the Tijuana-San Diego border region. Distinct spatial differences in fluxes of carbon dioxide (CO2), NOx, and particles were revealed across four sampling locations with the lowest fluxes occurring in a residential neighborhood and the highest ones at a port of entry characterized by heavy motor vehicle traffic. Additionally, observed emissions of NOx and carbon monoxide were significantly higher than those in emissions inventories, suggesting the need for further refinement of the inventories. The third campaign focused on emissions at a regional airport in Roanoke, Virginia. NOx and particle number emissions indices (EIs) were calculated for aircraft, in terms of grams of pollutant emitted per kilogram of fuel burned. Observed NOx EIs were ~20% lower than those in an international databank. NOx EIs from takeoffs were significantly higher than those from taxiing, but relative differences for particle EIs were mixed. Observed NOx fluxes at the airport agreed to within 25% of estimates derived from the NEI. The results of this research will provide greater knowledge of urban impacts to air quality and will improve associated management strategies through increased accuracy of official emissions estimates.
Ph. D.

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Horne, Vincent Howard. « The use of artificial neural networks for the prediction of pollutant emissions from aeroengines ». Ottawa : National Library of Canada = Bibliothèque nationale du Canada, 2002. http://www.nlc-bnc.ca/obj/s4/f2/dsk1/tape4/PQDD%5F0034/MQ65856.pdf.

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Singh, Bhupinder. « Flame blowout and pollutant emissions in vitiated combustion of conventional and bio-derived fuels ». [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0024935.

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Raggini, Lorenzo <1994&gt. « Modelling, control and testing of internal combustion engines to minimize consumption and pollutant emissions ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amsdottorato.unibo.it/10195/1/MODELLING%2C%20CONTROL%20AND%20TESTING%20OF%20INTERNAL%20COMBUSTION%20ENGINES%20TO%20MINIMISE%20CONSUMPTION%20AND%20POLLUTANT%20EMISSIONS.pdf.

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The objective of the PhD thesis was to research technologies and strategies to reduce fuel consumption and pollutants emission produced by internal combustion engines. In order to meet this objective my activity was focused on the research of advanced controls based on cylinder pressure feedback. These types of control strategies were studied because they present promising results in terms of engine efficiency enhancement. In the PhD dissertation two study cases are presented. The first case is relative to a control strategy to be used at the test bench for the optimisation of the spark advance calibration of motorcycle Engine. The second case is relative to a control strategy to be used directly on board of mining engines with the objective or reducing the engine consumption and correct ageing effects. In both cases the strategies proved to be effective but their implementation required the use of specific toolchains for the measure of the cylinder pressure feedback that for a matter of cost makes feasible the strategy use only for applications: • At test bench • In small-markets like large off-road engines The major bottleneck that prevents the implementation of these strategies on mass production is the cost of cylinder pressure sensor. In order to tackle this issue, during the PhD research, the development of a low-cost sensor for the estimation of cylinder pressure was studied. The prototype was a piezo-electric washer designed to replace the standard spark-plug washer or high-pressure fuel injectors gasket. From the data analysis emerged the possibility to use the piezo-electric prototype signal to evaluate with accuracy several combustion metrics compatible for the implementation of advanced control strategies in on-board applications. Overall, the research shows that advanced combustion controls are feasible and beneficial, not only at the test bench or on stationary engines, but also in mass-produced engines.

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Ruge, Montilla Jhonn Hamberth. « Modelling of tilt rotor mission performance to assess environmental impact ». Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/7292.

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New technologies and new rotorcraft operations are being developed in order to meet new environmental requirements such as noise reduction and less pollutant emissions. In this project a parametric study was developed over a tilt rotor model in order to assess the environmental impact in terms of operational parameter and fuel burned looking at pollutant emission released into the air such as NOx, CO, UHC, PM, CO2 & H2O In order to perform the study previously stated, a computational tool build on Simulink titled tilt rotor mission performance was developed to run a single mission profile as a base line making different operational variations on every mission segment looking at deviations over fuel burned and pollutant emissions. The contribution of pollutant emissions during the cruise segment was compared to other phases obtaining 80% of CO2 and H2O, 75% of CO and UHC, 77% of NOx, and 78% of PM. Also, comparing the distance flown of the tilt rotor with some turboprop aircraft, it was found that the fuel burned and levels of CO2 are higher using tilt rotor rather than turboprop aircraft. On the other hand this is much better than helicopters.

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Filimban, Hattan. « The effects of vehicle flow management on pollutant emissions : the M27 as a case study ». Thesis, Lancaster University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.442716.

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GRAMPELLA, MATTIA. « Framework definition to assess airport noise and aircraft emissions of pollutant based on mathematical models ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2012. http://hdl.handle.net/10281/29224.

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During the last ten years, in Civil Aviation sector there have been several initiatives for the development of policies to mitigate the environmental impacts. From ICAO to the single national authorities, like ENAC in Italy, it has been noted a strong increase in studies related to the specific environmental aspects concerning Aviation activities. The last three years have seen a stable 3% sector annual growth trend . Financial crisis, started in 2007, has not changed the estimation of traffic doubling volume for 2020. It is clear that this air traffic increase will request the upgrading of the airport infrastructures. It is very important that sustainable objectives of economic growth will be set in order to protect environment both on local scale, for communities living near airports, and on global scale, for the limitation of Greenhouse gases. In Italy the main aspect has always been noise pollution because the majority of airports are within densely populated areas. In Europe after the introduction of specific Directives, emission of pollutants in the atmosphere has seen an increase in perception not only for the development of mitigation projects like CleanSky, but also for the adoption of ETS for the Commercial Aviation sector. However, it does not exist yet a common set of rules around the world. This potentially can create some conflicting situations due to the interdependence between noise and emissions of pollutant . It is necessary to focus on all the environmental aspects to integrate the mitigation policies and operational procedures. The best choice will be made also taking into account capacity and safety issues in order to increase the effectiveness of the interventions. This thesis presents a method for the determination of two environmental indexes, the first regarding noise and the second atmospheric emissions produced by flight operations. The study case is the Italian airport system in the period 1999-2008. The indexes have been validated with mathematical models at the three major Lombardy airports. In this way, an “environmental tool” for airport impact analysis, both for actual conditions and future developments, has been created in order to simplify the assessment without using models or measures. As a descriptor of the airport noise, we opted for an index similar to the Day Night Level, DNL, which is based on the single event noise, weighed accordingly on whether it takes place in day-time or night-time. The name of the index is LVAyear. As for the impact on air quality, it was decided to assign a monetary cost to emissions to estimate the air traffic externalities in relation to the pollutants considered in this study (HC, NOx, CO, PM and SO2). The designed descriptor is called LAP (Local Air Pollution) index. Scenario simulations were done with mathematical models INM to calculate noise levels and EDMS to quantify emissions of contaminants. As for the structure of the work, chapter 1 and 2 introduce the general aspects concerning noise and gas emissions as well as mathematical models. The procedure for indexes definition is contained in chapter 3 while scenario analysis is described in chapter 4. Results are discussed in chapter 5.

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Eggenspieler, Gilles. « Numerical simulation of pollutant emission and flame extinction in lean premixed systems ». Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-06222005-132512/.

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Thesis (Ph. D.)--Aerospace Engineering, Georgia Institute of Technology, 2006.
Yedidia Neumeier, Committee Member ; Jerry Seitzman, Committee Member ; Fotis Sotiropoulos, Committee Member ; Tim Lieuwen, Committee Member ; suresh menon, Committee Chair.

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Chandru, Santosh. « Trans-boundary pollutant impacts of emissions in the Imperial Valley-Calexico region and from Southern California ». Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24770.

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Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2008.
Committee Chair: Russell, Armistead; Committee Member: Mulholland, James; Committee Member: Odman, Talat.

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Horn, Gregory. « The prediction of fuel economy and pollutant emissions to assess the benefits of direct injection gasoline engines ». Thesis, University of Nottingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395492.

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Meade, Wilbert E. « On Road Mobile Source Air Pollutant Emissions ; Identifying Hotspots and Ranking Roads in the State of Ohio ». Miami University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=miami1305070342.

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Dulbecco, Alessio. « Modeling of Diesel HCCI combustion and its impact on pollutant emissions applied to global engine system simulation ». Thesis, Toulouse, INPT, 2010. http://www.theses.fr/2010INPT0015/document.

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La législation sur les émissions de polluants des Moteurs à Combustion Interne (ICEs) est de plus en plus contraignante et représente un gros défi pour les constructeurs automobiles. De nouvelles stratégies de combustion telles que la Combustion à Allumage par Compression Homogène (HCCI) et l’exploitation de stratégies d’injections multiples sont des voies prometteuses qui permettent de respecter les normes sur les émissions de NOx et de suies, du fait que la combustion a lieu dans un mélange très dilué et par conséquent à basse température. Ces aspects demandent la création d’outils numériques adaptés à ces nouveaux défis. Cette thèse présente le développement d’un nouveau modèle 0D de combustion Diesel HCCI : le dual Combustion Model (dual - CM). Le modèle dual-CM a été basé sur l’approche PCM-FPI utilisée en Mécanique des Fluides Numérique (CFD) 3D, qui permet de prédire les caractéristiques de l’auto-allumage et du dégagement de chaleur de tous les modes de combustion Diesel. Afin d’adapter l’approche PCM-FPI à un formalisme 0D, il est fondamental de décrire précisément le mélange à l’intérieur du cylindre. Par consequent, des modèles d’évaporation du carburant liquide, de formation de la zone de mélange et de variance de la fraction de mélange, qui permettent d’avoir une description détaillée des proprietés thermochimiques locales du mélange y compris pour des configurations adoptant des stratégies d’injections multiples, sont proposés. Dans une première phase, les résultats du modèle ont été comparés aux résultats du modèle 3D. Ensuite, le modèle dual-CM a été validé sur une grande base de données expérimentales; compte tenu du bon accord avec l’expérience et du temps de calcul réduit, l’approche présentée s’est montrée prometteuse pour des applications de type simulation système. Pour conclure, les limites des hypothèses utilisées dans dual-CM ont été investiguées et des perspectives pour les dévélopements futurs ont été proposées
More and more stringent restrictions concerning the pollutant emissions of Internal Combustion Engines (ICEs) constitute a major challenge for the automotive industry. New combustion strategies such as Homogeneous Charge Compression Ignition (HCCI) and the implementation of complex injection strategies are promising solutions for achieving the imposed emission standards as they permit low NOx and soot emissions, via lean and highly diluted combustions, thus assuring low combustion temperatures. This requires the creation of numerical tools adapted to these new challenges. This Ph.D presents the development of a new 0D Diesel HCCI combustion model : the dual Combustion Model (dual−CM ). The dual-CM is based on the PCM-FPI approach used in 3D CFD, which allows to predict the characteristics of Auto-Ignition and Heat Release for all Diesel combustion modes. In order to adapt the PCM-FPI approach to a 0D formalism, a good description of the in-cylinder mixture is fundamental. Consequently, adapted models for liquid fuel evaporation, mixing zone formation and mixture fraction variance, which allow to have a detailed description of the local thermochemical properties of the mixture even in configurations adopting multiple injection strategies, are proposed. The results of the 0D model are compared in an initial step to the 3D CFD results. Then, the dual-CM is validated against a large experimental database; considering the good agreement with the experiments and low CPU costs, the presented approach is shown to be promising for global engine system simulations. Finally, the limits of the hypotheses made in the dual-CM are investigated and perspectives for future developments are proposed

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Cording, Amanda. « Evaluating Stormwater Pollutant Removal Mechanisms by Bioretention in the Context of Climate Change ». ScholarWorks @ UVM, 2016. http://scholarworks.uvm.edu/graddis/541.

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Stormwater runoff is one of the leading causes of water quality impairment in the U.S. Bioretention systems are ecologically engineered to treat stormwater pollution and offer exciting opportunities to provide local climate change resiliency by reducing peak runoff rates, and retaining/detaining storm volumes, yet implementation is outpacing our understanding of the underlying physical, biological, and chemical mechanisms involved in pollutant removal. Further, we do not know how performance will be affected by increases in precipitation, which are projected to occur in the northeastern U.S. as a result of climate change, or if these systems could act as a source or sink for greenhouse gas emissions. This research examines the design, construction, and development of monitoring methods for bioretention research, using the University of Vermont (UVM) Bioretention Laboratory as a case study. In addition, this research evaluates mobilization patterns and pollutant loads from road surfaces during the "first flush" of runoff, or the earlier part of a storm event. Finally, this research analyzes the comparative pollutant removal performance of bioretention systems on a treatment by treatment basis. At the UVM Bioretention Laboratory, eight lined bioretention cells were constructed with monitoring infrastructure installed at the entrance and at the subterranean effluent. A conventional, sand and compost based, bioretention soil media was compared to a proprietary media engineered to remove phosphorus, called Sorbtive Media™, under simulated increases in precipitation. Two drought tolerant vegetation mixes, native to the northeast, were compared for sediment and nutrient retention. Each treatment was sampled for soil gas emissions to determine if it was a source or a sink. The monitoring infrastructure designs used in this research allowed for the effective characterization of pollutant mass loads entering and exiting bioretention. Cumulative mass loads from stormwater were found to be highest for total suspended solids, followed by total Kjeldahl nitrogen, nitrate, non-labile phosphorus and soluble reactive phosphorus, in descending order by mass. Total suspended solids, total Kjeldahl nitrogen, and non-labile phosphorus mass were well retained by all bioretention treatments. However, the compost amendment in the conventional soil media was found to release labile nitrogen and phosphorus, far surpassing the mass loads in stormwater. When compared with conventional media, Sorbtive Media™ was highly effective at removing labile phosphorus and was also found to enhance nitrate removal. Systems containing deep-rooted vegetation (Panicum virgatum) were found to be particularly effective at retaining both labile and non-labile constituents. Overall, none of the bioretention treatments were found to be a significant source of N2O and were small sinks for CH4 in most treatments.

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Quaratino, Marco. « Virtual Calibration of CO2 and Pollutant Emissions of a High-Performance PHEV using Model-in-the-Loop Methodology ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/22053/.

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The study analyses the calibration process of a newly developed high-performance plug-in hybrid electric passenger car powertrain. The complexity of modern powertrains and the more and more restrictive regulations regarding pollutant emissions are the primary challenges for the calibration of a vehicle’s powertrain. In addition, the managers of OEM need to know as earlier as possible if the vehicle under development will meet the target technical features (emission included). This leads to the necessity for advanced calibration methodologies, in order to keep the development of the powertrain robust, time and cost effective. The suggested solution is the virtual calibration, that allows the tuning of control functions of a powertrain before having it built. The aim of this study is to calibrate virtually the hybrid control unit functions in order to optimize the pollutant emissions and the fuel consumption. Starting from the model of the conventional vehicle, the powertrain is then hybridized and integrated with emissions and aftertreatments models. After its validation, the hybrid control unit strategies are optimized using the Model-in-the-Loop testing methodology. The calibration activities will proceed thanks to the implementation of a Hardware-in-the-Loop environment, that will allow to test and calibrate the Engine and Transmission control units effectively, besides in a time and cost saving manner.

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Li, Xiang. « Characterization of Air Pollutant and Greenhouse Gas Emissions from Energy Use and Energy Production Processes in United States ». Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/1082.

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Air pollutants and greenhouse gases are two groups of important trace components in the earth’s atmosphere that can affect local air quality, be detrimental to the human health and ecosystem, and cause climate change. Human activities, especially the energy use and energy production processes, are responsible for a significant share of air pollutants and greenhouse gases in the atmosphere. In this work, I specifically focused on characterizing air pollutants and greenhouse gas emissions from the on-road gasoline and diesel vehicles, which is an important energy use process that largely contributes to the urban air pollutions, and from the natural gas production systems, which is a major energy production process that has increased dramatically in recent years and is expected to have a long-lasting impact in the future. We conducted multi-seasonal measurements in the Fort Pitt Tunnel in Pittsburgh, PA to update the on-road vehicle emission factors, to measure the size distribution of vehicle emitted particulate matter (PM), and to quantify the volatility distributions of the vehicle emitter primary organic aerosol (POA). We also conducted mobile measurements in the Denver-Julesburg Basin, the Uintah Basin, and the Marcellus Shale to quantify facility-level VOC emission from natural gas production facilities, and I constructed a gridded (0.1° × 0.1°) methane emission inventory of natural gas production and distribution over the contiguous US. I found that the stricter emission standards were effective on regulating NOx and PM emissions of diesel vehicles and the NOx, CO and organic carbon (OC) emissions of gasoline vehicles, while the elemental carbon (EC) emissions of gasoline vehicles did not change too much over the past three decades. Vehicle-emitted particles may be largely externally mixed, and a large fraction of vehicle-emitted particles may be purely composed of volatile component. Vehicle-emitted smaller particles (10– 60 nm) are dominantly (over 75%) composed of volatile component. The size-resolved particles and particles emission factors for both gasoline and diesel vehicles are also reported in this work. I also found that the POA volatility distribution measured in the dynamometer studies can be applied to describe gas-particle partitioning of ambient POA emissions. The POA volatility distribution measured in the tunnel does not have significant diurnal or seasonal variations, which indicate that a single volatility distribution is adequate to describe the gas-particle partitioning of vehicle emitted POA in the urban environment. The facility-level VOC emission rates measured at gas production facilities in all three gas production fields are highly variable and cross a range of ~2-3 order of magnitudes. It suggests that a single VOC emission profile may not be able to characterize VOC emissions from all natural gas production facilities. My gridded methane emission inventory over the contiguous US show higher methane emissions over major natural gas production fields compared with the Environmental Protection Agency Inventory of US Greenhouse Gas Emission and Sinks (EPA GHGI) and the Emission Database for Global Atmospheric Research, version 4.2 (Edgar v4.2). The total methane emissions of the natural gas production and distribution sector estimated by my inventory are 74% and 20% higher than the Edgar v4.2 and EPA GHGI, respectively. I also run the GEOS-Chem methane simulation with my inventory and EPA GHGI and compare with the GOSAT satellite data, and results show that my inventory can improve the model and satellite comparison, but the improvement is very limited. The size-resolved emission factors of vehicle emitted particles and POA volatility distribution reported in this work can be applied by the chemical transport models to better quantify the contribution of vehicle emissions to the PM in the atmosphere. Since our measurement of VOC emissions of natural gas production facilities were conducted before EPA started to regulate VOC emissions from the O&NG production facilities in 2016, the facility-level VOC emission rates reported in this work can serve as the basis for future studies to test the effectiveness of the regulatory policies. The spatially resolved methane emission inventory of natural gas production and distribution constructed in this work can be applied to update the current default methane emission inventory of GEOS-Chem, and the updated methane emission inventory can be used as a better a priori emission field for top-down studies that inversely estimate methane emissions from atmospheric methane observation.

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Lim, Guo Quan. « Evaluation of the Influence of Non-Conventional Sources of Emissions on Ambient Air Pollutant Concentrations in North Texas ». Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc804841/.

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Emissions of air pollutants from non-conventional sources have been on the rise in the North Texas area over the past decade. These include primary pollutants such as volatile organic compound (VOC) and oxides of nitrogen (NOx) which also act as precursors in the formation of ozone. Most of these have been attributed to a significant increase in oil and gas production activities since 2000 within the Barnett Shale region adjacent to the Dallas-Fort Worth metroplex region. In this study, air quality concentrations measured at the Denton Airport and Dallas Hinton monitoring sites operated by the Texas Commission on Environmental Quality (TCEQ) were evaluated. VOC concentration data from canister-based sampling along with continuous measurement of oxides of nitrogen (NOx), ozone (O3), particulate matter (PM2.5), and meteorological conditions at these two sites spanning from 2000 through 2014 were employed in this study. The Dallas site is located within the urban core of one of the fastest growing cities in the United States, while the Denton site is an exurban site with rural characteristics to it. The Denton Airport site was influenced by natural gas pads surrounding it while there are very few natural gas production facilities within close proximity to the Dallas Hinton site. As of 2013, there were 1362 gas pads within a 10 mile radius to the Denton Airport site but there were only 2 within a 10 mile radius to Dallas Hinton site. The Dallas site displayed higher concentrations of NOx and much lower concentrations of VOC than the Denton site. Extremely high levels of VOC measured at the Denton site corresponded with the increase in oil and gas production activities in close proximity to the monitoring site. Ethane and propane are two major contributors to the measured VOC concentration, suggesting the influence of fugitive emissions of natural gas. In Dallas, the mean and maximum values of ozone had decreased since 2000 by about 2% and 25%, respectively. Similarly NOx decreased by 50% and 18% in the mean and maximum values. However, the mean VOC value showed a 21% decrease while the maximum value increased by about 46%. In Denton, the change in percentage of ozone and NOx were similar to Dallas but the mean VOC concentration increased by about 620% while the max value increased 1960%. Source apportionment analysis confirmed the findings by identifying the production of natural gas to be the primary source of VOC emissions in Denton, while traffic sources were more influential near the Dallas site. In light of the recent proposal by EPA to revise the ozone standard, the influence of these new unconventional sources should be further evaluated.

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Deighton, Jacob. « Methane and Hazardous Air Pollutant Emissions from Marginally Producing “Stripper”Oil and Natural Gas Wells in Appalachian Ohio ». University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1554120171141725.

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Ferrarotti, Marco. « Experimental and numerical investigation of fuel flexibility and pollutant emissions in novel combustion technologies using renewable synthetic fuels ». Doctoral thesis, Universite Libre de Bruxelles, 2020. https://dipot.ulb.ac.be/dspace/bitstream/2013/312265/6/contraMF.pdf.

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By 2050, Europe needs to have drastically decoupled its economic growth from its emissions of CO2. This is a direct response to the compelling evidence from the increasing risks of climate change brought about by the anthropogenic Greenhouse Gas (GHG) emissions and pollutant emissions (NOx). A replacement of significant percent of fossil fuels with renewable energy sources will be needed. However, energy production from most renewable energy sources, is typically intermittent and unpredictable. This requires a reliable mid-long term energy storage to synchronize production and demand. The Power-to-Fuel option or chemical storage can be the key for a sustainable energy system. Indeed, converting the excess of renewable energy into second generation fuels will unlock a long-term and high-density energy storage, ensuring also a reduction of the carbon footprint. These ”green” non-conventional fuels are blends of CH4, H2, CO and NH3. However, to achieve Power-to fuel, the development of an efficient combustion technology, coupled with virtually zero pollutant emissions, stable working conditions with different load and fuel and significant energy saving is required. In the last years, a so-called MILD or flameless combustion has drawn attention for its ability of meeting the mentioned targets. However, the studies available in literature are conducted on Jet in hot co-flow-like systems or they face conventional fuels, such as natural gas or methane. The examples using non-conventional fuels are scarce and limited to few operating conditions. In this framework, this PhD thesis focuses on a threefold aspect. Experimental campaigns investigated fuel flexibility of flameless combustion in the ULB furnace. A progressive addition of hydrogen in methane enhanced combustion features, reducing the ignition delay time and increasing the reactivity of the system, possibly losing its flameless behavior. Indeed, a threshold of 25% H2 was defined for reaching flameless/MILD conditions, characterized by still low pollutant emissions and temperature peak. This is in line with the goal of introducing “green” hydrogen into the natural gas pipeline (up to 20%) to reduce CO2 emissions. Further experimental campaigns tested the role of the injection geometry (varying the air injector ID) and fuel lance length to reduce NO emissions and retrieve flameless/MILD conditions for high hydrogen content. Finally, ammonia/hydrogen blends were tested. Results suggests that stoichiometry has a major impact on NO emissions. An optimal window, minimizing both NO and NH3-slip emissions was defined using an equivalence ratio of 0.9. To qualitatively describe the observed trends, a simplified reactors network was considered. The analysis highlighted the most important reactions correlated to NO formation and the reason of the NO reduction at stoichiometry condition. On the other side an affordable and reliable numerical model was optimized and tested in the Adelaide Jet in Hot Co-flow burner. The latter is a simplified burner capable of mimicking MILD combustion conditions. A set of RANS simulations were run using the Partially Stirred Reactor (PaSR) approach, investigating different mixing model formulations: a static, a fractal-based and a dynamic formulation, based on the resolution of transport equations for scalar variance and dissipation rate. A study about the role of combustion models and kinetic mechanisms on the prediction of NO formation was also conducted. Finally, an analysis of the choice of a Heat Release Rate (HRR) marker for MILD (HM1 flame) and not MILD (HM3 flame) conditions was carried out. Once having awareness of the capability of the proposed numerical model, simulations were conducted to define the key aspects in simulating a flameless furnace, varying the composition of the fuel, considering methane/hydrogen and ammonia/hydrogen blends. In particular, for the latter case, existing kinetic schemes showed a major over-estimation of NO emissions, reason why an optimization study was conducted in a simplified reactor (well stirred reactor) using a Latin Hypercube Sampling. Finally, the first-of-its-kind digital twin based on CFD simulations for a furnace operating in flameless combustion conditions was created. A reduced- order model (ROM) based on the combination of Proper Orthogonal Decomposition (POD) and Kriging was developed for the prediction of spatial fields (i.e. temperature) as well as pollutant in the exhausts.
D’ici 2050, l’Europe devra découpler sa croissance économique de ses émissions de CO2. Il s’agit d’une réponse nécessaire au changement climatique et à la pollution de l’air induits par les émissions atmosphérique de gaz à effet de serre (GES) et de polluants (NOx). Un remplacement d’un pourcentage significatif des combustibles fossiles par des sources d’énergie renouvelables sera nécessaire. Cependant, la production d’énergie à partir des sources renouvelables est généralement intermittente et imprévisible. Cela nécessite un stockage d’énergie fiable à moyen et long terme, pour synchroniser la production et la demande d’énergie. L’option Power-to-Fuel, ou stockage chimique, peut être la clé d’un système énergétique durable. En effet, la conversion de l’excès d’énergie renouvelable en carburants de deuxième génération permettra de débloquer un stockage d’énergie à long terme et à haute densité, en assurant également une réduction de l’empreinte carbone. Ces carburants non conventionnels « verts » sont des mélanges de CH4, H2, CO et NH3. Cependant, pour exploiter le potentiel du Power-to-Fuel, il est nécessaire de développer une technologie de combustion efficace, avec des émissions de polluants pratiquement nulles, assurant des conditions de travail stables avec une charge et des carburants différents et des économies d’énergie significatives. Au cours des dernières années, une combustion dite « MILD », ou sans flamme, a attiré l’attention pour sa capacité à atteindre les objectifs mentionnés. Cependant, les études disponibles dans la littérature sont menées sur des systèmes de laboratoire (jet in hot co-flow) et avec des carburants conventionnels comme le gaz naturel ou le méthane. Les exemples utilisant des carburants non conventionnels sont rares et limités à quelques conditions de fonctionnement.Dans ce cadre, cette thèse de doctorat se concentre sur un triple aspect.Des campagnes expérimentales ont étudié la flexibilité du combustible dans un four sans flamme installé à l'ULB. L’ajout progressif d’hydrogène dans le méthane permet d’améliorer les caractéristiques de combustion, en réduisant le délai d’allumage et augmentant la réactivité du système, ce qui, par contre, cause un éloignement du système des conditions sans flamme. En effet, un seuil supérieur de 25% H2 a été identifié pour les mélanges méthane/hydrogène, pour travailler dans des conditions sans flammes (MILD), caractérisées par une faible augmentation de température et des émissions de polluants amoindries .Cela est conforme à l’objectif d’introduire de l’hydrogène « vert » dans le gazoduc (jusqu’à 20%) afin de réduire les émissions de CO2. D’autres campagnes expérimentales se sont focalisées sur le rôle de la géométrie d’injection (variation du diamètre de l’injecteur d’air) et de la longueur de la lance du carburant pour réduire les émissions des oxydes d’azote et récupérer les conditions sans flamme/MILD pour une teneur élevée en hydrogène. Enfin, des mélanges ammoniac/hydrogène ont été testés. Les résultats suggèrent que la stœchiométrie a un impact majeur sur les émissions d’oxydes d’azote. Une fenêtre optimale minimisant les émissions de NO et d’ammoniac imbrulées a été définie en utilisant un rapport d'équivalence de 0,9. Pour tracer qualitativement les tendances observées, un réseau de réacteurs simplifié a été construit. L’analyse a mis en évidence les réactions les plus importantes pour la formation des NOx et elle a permis de justifier la réduction des oxydes d’azote à l’état stœchiométrique.De l’autre côté, un modèle numérique robuste et fiable a été optimisé et testé pour le brûleur Jet in Hot Co-flow de l’Université d’Adelaide. Ce dernier est un brûleur simplifié capable de simuler les conditions de combustion MILD/sans flamme. Un ensemble de simulations RANS ont été effectuées à l’aide de l’approche du réacteur partiellement agité (Partially Stirred Reactor – PaSR - en anglais), en examinant les différentes formulations de modèles de mélange :une formulation statique, fractale et dynamique, basée sur la résolution des équations de transfert pour la variance scalaire et le taux de dissipation. Une étude sur le rôle des modèles de combustion et des mécanismes cinétiques dans la prédiction de la formation des oxydes d’azote a également été réalisée. Enfin, une analyse sur le choix d’un marqueur de taux de dégagement de chaleur (Heat Release Rate – HRR – en anglais) pour les conditions MILD et non MILD a été réalisée. Après validation, les modèles développés ont été utilisés pour définir les aspects clés de la simulation d’un four sans flamme, en variant la composition du combustible, pour des mélanges méthane/hydrogène et ammoniac/hydrogène. En particulier, pour ce dernier cas, les schémas cinétiques existants ont montré une surestimation importante des émissions d’oxydes d’azote, raison pour laquelle une étude d’optimisation a été menée dans un réacteur simplifié.Enfin, le premier jumeau numérique en son genre, basé sur des Simulations numériques de Dynamique de Fluides (CFD – Computational Fluid Dynamics en anglais) pour un four fonctionnant dans des conditions de combustion sans flamme, a été créé. Un modèle à ordre réduit (ROM – Reduced Order Model en anglais) basé sur la combinaison de la Décomposition Orthogonale aux valeurs Propres (POD) et du Kriging a été développé pour la prédiction des variables d’intérêt (température et espèces chimiques majeures) ainsi que des polluants dans les fumées.
Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished

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Copani, Giuseppe. « Benefit of including bioactive legumes (sainfoin, red clover) in grass-based silages on ruminant production and pollutant emissions ». Thesis, Clermont-Ferrand 2, 2015. http://www.theses.fr/2015CLF22594/document.

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Les légumineuses permettent de réduire les intrants en élevage (engrais, concentrés) en raison notamment de leurs niveaux élevés en protéines. Cependant, à la fois pendant le processus d'ensilage et celui de fermentation dans le rumen, les protéines peuvent subir une importante dégradation, ce qui affecte la valeur nutritive des fourrages et induit des rejets d'azote (N) importants, notamment dans l'urine. Certaines légumineuses peuvent alors être d'un intérêt particulier car elles produisent des composés secondaires qui peuvent modifier positivement les processus fermentaires et digestifs. Ainsi, les tannins condensés (CT) présents dans le sainfoin (SF, Onobrychis viciifolia) sont capables de se lier aux protéines, réduisant leur dégradation dans le silo et le rumen et se traduisant par un transfert de l'excrétion d'azote de l'urine vers les fèces. Le trèfle violet (RC, Trifolium pratense) contient la polyphénoloxydase (PPO), une enzyme qui catalyse l'oxydation de différents composés phénoliques en quinones. Comme les CTs, les quinones sont capables de former des complexes avec les protéines permettant de réduire leur dégradation dans le silo et le rumen. L'objectif de cette thèse était alors d'étudier et de quantifier les bénéfices potentiels de l'utilisation de ces deux espèces de légumineuses bioactives sur i) la qualité et la conservation des ensilages, ii) la fermentation ruminale, l'efficacité digestive et les performances des ovins, et iii) l'empreinte environnementale (excrétion d'N et de CH4). Nous avons effectué deux essais in vitro et deux essais in vivo, basés sur des ensilages composés de ces deux légumineuses, seules ou en mélange avec une graminée (la fléole- T, Phleum pratense L.) qui nous a servie de contrôle. Les essais in vitro nous ont permis de nous focaliser sur la qualité et la conservation des ensilages ainsi que sur la fermentation ruminale, tandis que les essais in vivo se sont concentrés sur la performance et l'efficacité digestive des agneaux, ainsi que sur leur bilan azoté et leurs émissions de CH4. L'inclusion de légumineuses bioactives dans les ensilages d'herbe a amélioré la qualité du fourrage, la fermentation pendant le processus d'ensilage ainsi que la protection des protéines contre une dégradation au sein du silo et du rumen. Globalement, l'alimentation des agneaux avec des mélanges comportant ces légumineuses s'est traduite par une augmentation de l'ingestion de matière sèche, en comparaison des agneaux alimentés avec la graminée pure. Néanmoins, en raison de la digestibilité nettement plus faible de T-SF, probablement due à une composition et une nature des fibres différentes ainsi qu'à la présence de CT, les agneaux ayant reçu T-SF ont montré une ingestion et des performances plus faibles que ceux ayant reçu les ensilages contenant RC. Dans le rumen, il semble que les protéines de RC aient été plus protégées de la dégradation que celles de SF, tandis que dans la suite du tractus digestif, les complexes formés entre protéines et CT (avec SF) se seraient moins dissociés que ceux formés entre protéines et quinones (avec RC), ce qui pourrait en partie expliquer le transfert d'excrétion de l'N de l'urine vers les fèces, observé chez les agneaux alimentés avec T-SF et bénéfique pour l'environnement. SF a également permis de réduire légèrement les émissions de CH4. Ainsi, utiliser des légumineuses bioactives dans les pratiques d'alimentation des ruminants apparaît une stratégie prometteuse pour fournir des produits animaux de façon plus durable. Nos résultats montrent que chaque espèce apporte des avantages différents, plutôt orientés vers la qualité de l'aliment et les performances animales pour RC mais plutôt orientés vers la réduction des rejets pour SF. Des recherches complémentaires sont donc nécessaires pour mieux caractériser ces avantages et élargir les investigations à d'autres espèces, d'autres mélanges et d'autres bénéfices potentiels. (...)
Fodder legume species allow to reduce inputs in livestock breeding systems (fertilizer, concentrates) notably because they contain high levels of crude proteins which are of primary importance in ruminant nutrition. However, during both silage and rumen fermentation processes, proteins are submitted to degradation which affects forage nutritive value and leads to nitrogen (N) losses notably via urine. Some specific legumes can then be of particular interest as they produce plant secondary compounds that can positively affect silage and digestive processes. Condensed tannins (CTs) present in sainfoin (SF, Onobrychis viciifolia) are able to bind with proteins thereby reducing their degradation in the silo and the rumen, resulting in a shift in N excretion from urine to faeces. Red clover (RC, Trifolium pratense) contains polyphenol oxidase (PPO), an enzyme that catalyses the oxidation of different phenolics into quinones. As CTs, quinones are able to form complexes with proteins that will similarly reduce their degradation in the silo and the rumen. The aim of this thesis was to investigate and quantify the potential benefits of using these two bioactive legume species on i) quality and conservation of silages, ii) rumen fermentation, digestive efficiency and sheep performance, and iii) environmental footprint (N excretion and CH4 emissions). We conducted two in vitro and two in vivo trials which were based on silages of pure legumes or of different mixtures with the grass species (timothy T, Phleum pratense L.), which served as control. In the in vitro trials, we focussed on silage quality, silage conservation and rumen fermentation, while in the in vivo trials, we focussed on lambs' performance, digestion efficiency, N balance and CH4 emissions. Including bioactive legumes in mixtures with grass improved, compared to pure grass, forage quality and fermentation during the silage making process, as well as proteins' protection from degradation within both the silos and the rumen. Lambs fed with the mixtures involving legumes responded with an increase in DM intake compared to their counterparts fed with T. Nevertheless, due to a possibly different fibre composition and to the presence of CT which impaired SF digestibility, lambs that consumed T-SF showed lower intake and performance than those that received RC-containing silages. In the rumen, RC proteins appeared more protected from degradation than SF ones, while in the subsequent parts of the digestive tract, the proteins-CT complexes (from SF) might less dissociate than the proteins-quinones ones (from RC). This could partly explain the environment-friendly shift in N excretion from urine to faeces when animals are fed with T-SF. SF also allowed to slightly reduce CH4 emissions. Thus, utilizing bioactive legumes in livestock feeding practices is a promising strategy to produce animal products more sustainably. Our results show different benefits relative to the bioactive legume species involved, directed towards boosted forage quality and animals' performance for RC but towards lowered wastes for SF. Further research is thus needed to better characterize these benefits and enlarging investigations to other plant species, mixtures and potential benefits (e.g. health). This will help to determine the appropriate choice of plant species according to the objectives

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GASTALDI, PATRICK. « INFLUENCE OF THE MIXTURE PREPARATION ON THE COMBUSTION IN DIRECT INJECTION ENGINES ». Doctoral thesis, Universitat Politècnica de València, 2015. http://hdl.handle.net/10251/48534.

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During the last two centuries, the development of the internal combustion engine has followed the evolution of the customer expectations. From the race for pure performances, high power, and fun to drive, perfectly well illustrated by the fabulous Mercedes 300 SL, the focus moved towards fuel efficient engines under the pressure of the still increasing oil prices. The well-known Diesel powertrain, up to this period limited to industrial vehicles, suddenly became the object of many researches, even for automotive manufacturers, specialists for sport cars. Technologic developments, mainly concerning turbocharging and injection, allowed the opening of the passenger cars market to CI engines due to acceptable noise, power and still unreachable efficiency. On the gasoline side, direct injection moved from racing to economic cars by the introduction of the stratified combustion. More recently, the pressure rose for dramatically reducing the air pollution, both in urban areas, by limiting NOx and soot, but also, at the scale of the earth, for managing CO2 rejections and thereby enlarging the efforts on efficiency. The two first combustion systems described in this document are concerning spray guided and air guided design alternatives to obtain a fuel stratification, and thereby operate the gasoline engine without throttling the air intake, aiming at a better fuel efficiency. The first concept, called MID3S, was based on a 3 valve combustion chamber with a large squish area and a high compression ratio over 12; inspired from the May Fireball system, it was developed with a house made high pressure injector operating up to 80 bars with an outwardly opening needle. An ultra-lean flame-able mixture was formed at WOT in the vicinity of the spark plug for different operating points as low as idle, while the maximum performances were quite close to the targeted 37 kW/l. The efficiency was significantly improved compared to a similar MPI engine while CO and HC were quite acceptable. On the contrary, NOx and soot would have to be improved. The robustness of the squish aerodynamic motion was unfortunately balanced by the sensitivity of spray angle and penetration versus the back pressure and thereby late injection timings, creating plug wetting and fouling. The hollow cone structure of the fuel plume was clearly responsible of this behavior, especially because of the effect of the air entrainment inside the spray. An increase of the injection pressure from 30 to 80 bar, and probably upper, would probably reduce this effect. Concerning methodologies, a dedicated cylinder head was designed with two endoscope locations in order to visualize the interaction between spray, air, walls and combustion –or more precisely soot- with a high speed camera operating within visible wavelengths. The spray structure, formed by a succession of ligaments at the surface of the plume, was clearly emphasized in atmospheric conditions. The second design, called K5M, was based on an adjustable high tumble motion generated in the intake port. A swirl injector provided by Siemens and located between the two intake valves of the pent roof chamber, was operated until 80 bar. Mixture preparation was relying on the interaction between the air motion and the spray, the tumble velocity deviating fuel droplets towards the spark plug situated at the center of the chamber. 3D CFD simulation, PIV and LIF visualization techniques on an optical single cylinder engine were used in parallel in order to understand the spatial evolution of the equivalence ratio during the cycle and the ability to operate the engine at WOT, even at part load. At low BMEP and speed, the natural reduction of the tumble intensity might have been followed by a significant reduction of the injection pressure in order to secure an accurate balance between the two momentum energies; unfortunately, both high cycle to cycle aerodynamic fluctuations and a poor spray atomization at 30 bar didn’t allow to achieve an acceptable ignition stability at low loads due to a too lean mixture in the plug vicinity. Protruded electrodes could have been a solution to the problem but their reliable use in serial life was not secured. On the contrary, mid load performances were globally adequate. The third concept is concerning Diesel combustion aiming at very low NOx and soot emissions by using an innovative injection system. The basic idea relies on the use of a quite homogeneous combustion at low load –called Mild HCCI- and on a diffusion controlled one at higher loads. Based on two injections close one of the other in the vicinity of TDC, the Mild HCCI allows to moderate the combustion noise inherent to the premixed burning phase as the fuel injected during the second injection cools down the first combustion; the advantages of very low NOx and soot emissions until around 8 bar BMEP are meanwhile maintained. Above this value, the noise level becomes unacceptable for automotive applications and the come back to a conventional diffusive combustion becomes mandatory. Based on early academic investigations pointing out the positive effect of small nozzle holes associated to high injection pressures in terms of soot via a significant difference between the lift-off length and the liquid penetration length, an innovative injection system was adapted to a conventional combustion chamber. The first conclusion was concerning a significant improvement of the NOx/soot tradeoff at mid and high loads with quite usual EGR rates. This advantage was due to a much better fuel atomization linked to both small holes and high pressures. The second conclusion was related to the possibility to achieve a “0 soot/ 0 NOx” combustion at high loads while very much increasing EGR and air mass flows. In this case, a Lifted Flame Diffusion Controlled combustion was generated, confirming on a scale 1 engine the results obtained in academic conditions. Nevertheless, the use of 3D simulation allowed to demonstrate that mixture preparation was only one part of the result; the location of the different stages of the combustion in a Kamimoto diagram, much away from the NOx and soot peninsula, highlighted the impact of the LTC (Low Temperature Combustion) thermodynamics. Unfortunately, despite these good results, industrially available EGR and air systems are not able to provide the necessary mass flows. Concerning tools, the development steps were followed by intensive spray visualizations for both the liquid and the vapor phases, in conditions closer and closer to the actual engine. These measurements allowed to precisely evaluate the impact of the diameter size, the rail pressure and the oxygen content on the difference between lift-off and liquid lengths. Finally, the importance of coupling investigation tools like visualization and 3D simulation in conditions as close as possible to the actual engine in terms of temperature, pressure and timing –eg the ability to record a complete mixture and combustion cycle- has been emphasized for both future SI and Diesel engines. In particular, the forecasted increase of the rail pressures will lead to re-optimize the different available spray models and eventually to re-adapt them in terms of physical phenomena because of the great variations of the spray velocity and of the Weber number. The presence of cavitation in the nozzle holes will also have to be taken into account as it has a key role versus coking. In conclusion, it is quite clear that the development of stratified gasoline and low emissions Diesel engines will more and more rely on the mixture preparation and on its association with low gas temperatures.
Gastaldi, P. (2015). INFLUENCE OF THE MIXTURE PREPARATION ON THE COMBUSTION IN DIRECT INJECTION ENGINES [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48534
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Chatel, Juliette. « On the assessment of pollutant emissions : the role of flue gas flow rate measurement : Critical review and industrial feedback ». Thesis, KTH, Energiteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-200393.

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From a bottom-up perspective, the assessment of flow rate of stack flue gases is crucial being the very first brick of the calculation. With the concentration of pollutant, it gives access to the amount of pollutant released in the atmosphere. Nevertheless, flow rate measurement has not been well-framed and can be poorly controlled, leading to large uncertainties. The recent launch of the European Standard EN 16 911 has enlighten the lack of expertise concerning the flow rate assessment in the industry. That is why RECORD, the project sponsor, conscious of the possible lack of expertise and the possible unreliability of the measurement is willing to understand the requirements; theoretical, technical and regulatory; for a reliable pollutant emissions measurement in accordance with the EU regulation in the field of waste treatment and incineration. Thus, this study offers the theoretical, operational and regulatory keys to realize a reliable flow rate measurement. 9 methods are identified for stack flue gases flow rate measurement. For each of these methods an ID-card, based on bibliographical researches, supplier’s interviews and representatives of the industry’s feedbacks, has been built containing information required for a reliable measurement. This thesis will contribute to a report that will offers all the keys for a reliable velocity/flow rate measurement in the waste treatment (domestic waste incineration mainly but it can also be useful in every industry that releases flue gas in the atmosphere: chemistry, steel manufacture, etc.). Moreover, this study proposes an analysis of the European Standard related to flow rate measurement in the industry and enlightens the key information related to these standards for an industrial operator. Finally, in relation with the complete report published on the RECORD website, a comparison tool of the 9 technologies is created to guide the industrial in their flow rate measurement. Once the best technology has been selected thanks to the comparison tool, the ID-card gives the key to realize a reliable measurement with the selected method. Finally, the theoretical part and the standard analysis have to be used as a frame for all the technologies.

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Zaidi, Syed Azhar Mehdi. « The control of combustion and pollutant emissions of pulverised fuel flames through the implementation of fuzzy logic based embedded reasoning ». Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398941.

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ACUTO, Francesco. « Integrating vehicle specific power methodology and microsimulation in estimating emissions on urban roundabouts ». Doctoral thesis, Università degli Studi di Palermo, 2021. http://hdl.handle.net/10447/519477.

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In this study pollutant emissions were estimated from VSP modal emission rates and the distribution of time spent in each VSP mode obtained from the speed profiles both gathered in the field and simulated in AIMSUN at a sample of urban roundabouts. The versatility of the micro-simulation model for a calibration aimed at improving accuracy of emissions estimates was tested in order to ensure that second-by-second trajectories experienced in the field by a test vehicle through the sampled roundabouts properly reflected the simulated speed profiles. The first results which the thesis will refer, confirmed the feasibility of the smart approach that integrates the use of field-observed and simulated data to estimate emissions at urban roundabouts. It is also revealed friendly in collecting information via smartphone and in the subsequent data analysis and provided suggestions for large-scale data collection through a digital community. Another goal of this research is to investigate about the environmental performance after a conversion of a traditional existing roundabout into a turbo-roundabout. This aspect has been considered a positive approach for a novel attitude in the performance evaluation of road networks to align the infrastructural design with the aim of sustainable and low-emission mobility. The main finding provided from this study is referred to the positive potential of a novel attitude in the conceptualization and performance evaluation of road units in order to align urban infrastructural projects with the worldwide shared long-term ambitions for a low-emission mobility.

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Arthozoul, Simon Jean Louis. « Study of the association of premixed and diffusive combustion processes on the combustion and pollutant emissions in a mid-size Diesel engine ». Doctoral thesis, Universitat Politècnica de València, 2016. http://hdl.handle.net/10251/63262.

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[EN] The main objective of this thesis is the analysis and comprehension of the association of two different combustion concepts (premixed and diffusive combustion) on the pollutant emissions and engine performance in a mid-size Diesel engine. The evaluation is performed at mid and high load conditions, where the implementation of premixed combustion is generally challenging. The association of the two combustion modes is hard to attain in a conventional Diesel engine, especially the preparation of the premixed charge with early pilot injection. Therefore, the approach followed during the study has been divided in two main steps: first, the bibliography on the subject is reviewed and two strategies avoiding the main issues mentioned in the literature are grossly evaluated in order to estimate their potential for emission reduction. Second, a deeper study of the combustion processes and emissions formation is performed, focusing only on the partially premixed combustion strategies that actually have the potential for emissions reduction. Along the second part of the study, the association of premixed and diffusive combustion is evaluated together with variation of conventional calibration parameters such as the intake oxygen concentration (via exhaust gas recirculation), the boost pressure and the start of the main injection timing, at different engine speed and load conditions. A cross analysis of the results obtained is performed in order to understand the key reasons that permit the reduction of the pollutant emissions with this strategy. In a final part of the thesis, the partially premixed combustion strategies studied are confronted with the challenges they might face when really considered for their introduction in a production engine (oil-dilution, noise...) to finally conclude on their technological potential.
[ES] El objetivo principal de la Tesis es el an álisis y la comprensi ón de la asociaci ón de dos conceptos de combusti ón diferentes (combusti ón en premezcla y por difusi ón) en las emisiones contaminantes y las prestaciones en un motor Diesel de cilindrada media. La evaluaci ón se realiza en condiciones de media y alta carga, en la cuales la implementaci ón de una combusti ón premezclada es generalmente complicada. La asociaci ón de los dos modos de combusti ón es dif cil de conseguir en un motor Diesel convencional, especialmente la preparaci ón de la carga premezclada con inyecci ón piloto adelantada. Por esa raz ón, el estudio se divide en dos partes principales: primero se revisa la bibliograf ía acerca del tema, centrando la atenci ón en dos estrategias que permiten evitar los principales problemas evocados en la literatura, determinando su potencial para la reducci ón de las emisiones contaminantes. En un segundo lugar, se realiza un estudio m as profundo de los procesos de combusti ón y de formaci ón de contaminantes, centr ándose únicamente en las estrategias de combusti ón parcialmente premezclada que sí tienen el potencial para reducir las emisiones contaminantes. En la segunda parte del estudio, se aborda la asociaci ón de combustiones premezclada y por difusi ón junto con la variaci ón de par ametros de calibraci on convencionales como la concentraci ón de ox ígeno en la admisi ón (por medio de recirculaci ón de los gases de escape), la presi ón de sobrealimentaci ón y el inicio de la inyecci ón principal, en diferentes condiciones de r egimen y de carga del motor. El an álisis cruzado de los resultados se realiza con el af án de entender las razones claves de los procesos que permiten la reducci ón de las emisiones contaminantes con esta estrategia. Como etapa final de esta tesis, se confrontan las estrategias de combusti ón parcialmente premezclada estudiadas con los problemas a los cuales podr ían llevar si realmente se considerar a su implementaci ón y un motor de serie (diluci ón de aceite, ruido...) para finalmente concluir sobre su potencial tecnol ógico.
[CAT] L'objectiu principal de la tesi es l'an alisi i la comprensi o de l'associaci o de dos conceptes de combusti o diferents (combusti o en premescla i per difusi o) en les emissions contaminants i les prestacions en un motor Di esel de cilindrada mitjana. L'avaluaci o es realitza en condicions de mitja i alta c arrega, en las quals la implementaci o d'una combusti o premesclada es generalment complicada. L'associaci o dels dos modes de combusti o es dif cil d'aconseguir en un motor Di esel convencional, especialment la preparaci o de la c arrega premesclada amb injecci o pilot avan cada. Per eixa ra o, l'estudi es divideix en dos parts principals: primer es revisa la bibliogra a sobre el tema, centrant l'atenci o en dos estrat egies que permeten evitar els principals problemes evocats en la literatura, determinant el seu potencial per a la reducci o de les emissions contaminants. En un segon lloc, es realitza un estudi m es profund dels processos de combusti o i de formaci o de contaminants, centrant-se unicament en les estrat egies de combusti o parcialment premesclada que si que tenen el potencial per a reduir les emissions contaminants. En la segona part de l'estudi, s'aborda l'associaci o de combustions premesclada i per difusi o junt amb la variaci o de par ametres de calibratge convencionals com la concentraci o d'oxigen en l'admissi o (per mitj a de recirculaci o dels gasos d'escapament), la pressi o de sobrealimentaci o i l'inici de la injecci o principal, en diferents condicions de r egim i de c arrega del motor. L'an alisi creuat dels resultats es realitza amb l'afany d'entendre les raons claus dels processos que permeten la reducci o de les emissions contaminants amb esta estrat egia. Com a etapa final d'esta tesi, es confronten les estrat egies de combusti o parcialment premesclada estudiades amb els problemes als quals podrien portar si realment es consideraria la seua implementaci o en un motor de s erie (diluci o d'oli, soroll...) per a finalment concloure sobre el seu potencial tecnol ogic.
Arthozoul, SJL. (2016). Study of the association of premixed and diffusive combustion processes on the combustion and pollutant emissions in a mid-size Diesel engine [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/63262
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Mameri, Fateh. « Caractérisation multi-physique et multi-échelle d'une installation de conversion d'énergie : application à une unité de cogénération biomasse ». Thesis, Valenciennes, 2018. http://www.theses.fr/2018VALE0049/document.

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La micro-cogénération désigne la production simultanée de deux énergies finales et utilisables à partir d’une seule source d’énergie primaire. Le cas le plus fréquent est la production de la chaleur et de l’électricité. En France, la micro-cogénération concerne les petites puissances (< 36 kWel). Son intérêt réside dans des rendements globaux supérieurs à ceux obtenus dans le cas d’une production séparée équivalente d’électricité et de chaleur. Dans le cas d’une micro-cogénération biomasse, la chaleur est fournie par une chaudière biomasse qui est couplée à un cogénérateur via un échangeur de chaleur gaz – gaz. À cette échelle de puissance, les moteurs à combustion externe ou moteurs à air chaud sont les plus indiqués comme cogénérateur. L’objet de cette thèse est de caractériser et de modéliser une unité de micro-cogénération biomasse qui se compose d’une chaudière domestique à pellets de puissance 30 kWth, d’un moteur à air chaud de type Ericsson et d’un échangeur air–gaz brûlés inséré dans la chambre de combustion de la chaudière. Des modèles dynamiques 0D de la chaudière biomasse et de l’échangeur de chaleur air – gaz brûlés sont développés pour simuler les phases transitoires et représenter l’évolution des variables du système au cours du temps. Les modèles 0D dynamiques ont été validés par des mesures expérimentales. Ils sont capables d'évaluer les performances énergétiques et les pertes de puissance et de quantifier les transferts thermiques entre les fluides de travail (eau et air), les gaz brûlés et les parois en différentes zones au sein du système considéré (chaudière ou échangeur de chaleur air – gaz brûlés). Une post-combustion a été réalisée en injectant de l’air secondaire à différents débits, chauffé à différentes températures dans la partie haute de la chambre de combustion de la chaudière. Des mesures des émissions polluantes au niveau de la cheminée de la chaudière ont été réalisées afin d’examiner l’influence de la post-combustion. Les principaux composants mesurés sont : le dioxyde de carbone, l’oxygène, le monoxyde de carbone et les oxydes d’azote
Micro-cogeneration refers to the simultaneous production of two final and usable energies from a single primary energy source. The most common case is the production of heat and electricity. In France, micro-cogeneration concerns small powers (< 36 kWel). Its interest lies in higher efficiencies than those obtained in the case of an equivalent separate production of electricity and heat. In the case of biomass micro-CHP system, the heat is supplied by a biomass boiler that is coupled to a cogenerator via a heat exchanger. For this power, external combustion engines or hot air engines are the most suitable. In the case of The purpose of this PhD thesis work is to characterize and model a biomass micro-CHP unit, with a biomass boiler (30 kWth), an Ericsson engine and an air-flue gas heat exchanger inserted inside the combustion chamber of the boiler. Dynamic models 0D of the biomass boiler and the air-flue gas heat exchanger are developed to simulate the transient phases and to represent the evolution of the variables as a time function. Dynamic 0D models have been validated by experimental measurements. They evaluate the energy performances and power losses and quantify heat transfer between working fluids (water and air), flue gases and walls in different zones in the considered system (boiler or air-flue gas heat exchanger). A post-combustion is investigated by injecting secondary air at different flow rates and different temperatures in the upper part of the boiler combustion chamber. Experimental measurements of pollutant emissions in the boiler chimney are performed to examine the post-combustion influence. The main pollutants measured are: carbon dioxide, oxygen, carbon monoxide and nitrogen oxides

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Dohanich, Francis Albert. « On-Road Remote Sensing of Motor Vehicle Emissions : Associations between Exhaust Pollutant Levels and Vehicle Parameters for Arizona, California, Colorado, Illinois, Texas, and Utah ». Thesis, University of North Texas, 2003. https://digital.library.unt.edu/ark:/67531/metadc5524/.

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On-road remote sensing has the ability to operate in real-time, and under real world conditions, making it an ideal candidate for detecting gross polluters on major freeways and thoroughfares. In this study, remote sensing was employed to detect carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxide (NO). On-road remote sensing data taken from measurements performed in six states, (Arizona, California, Colorado, Illinois, Texas, and Utah) were cleaned and analyzed. Data mining and exploration were first undertaken in order to search for relationships among variables such as make, year, engine type, vehicle weight, and location. Descriptive statistics were obtained for the three pollutants of interest. The data were found to have non-normal distributions. Applied transformations were ineffective, and nonparametric tests were applied. Due to the extremely large sample size of the dataset (508,617 records), nonparametric tests resulted in "p" values that demonstrated "significance." The general linear model was selected due to its ability to handle data with non-normal distributions. The general linear model was run on each pollutant with output producing descriptive statistics, profile plots, between-subjects effects, and estimated marginal means. Due to insufficient data within certain cells, results were not obtained for gross vehicle weight and engine type. The "year" variable was not directly analyzed in the GLM because "year" was employed in a weighted least squares transformation. "Year" was found to be a source of heteroscedasticity; and therefore, the basis of a least-squares transformation. Grouped-years were analyzed using medians, and the results were displayed graphically. Based on the GLM results and descriptives, Japanese vehicles typically had the lowest CO, HC, and NO emissions, while American vehicles ranked high for the three. Illinois, ranked lowest for CO, while Texas ranked highest. Illinois and Colorado were lowest for HC emissions, while Utah and California were highest. For NO, Colorado ranked highest with Texas and Arizona, lowest.

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Boucher, Aymeric. « Modélisation de la formation des polluants au sein des foyers aéronautiques par une méthode de chimie tabulée ». Thesis, Châtenay-Malabry, Ecole centrale de Paris, 2015. http://www.theses.fr/2015ECAP0006/document.

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La réduction des émissions polluantes des foyers aéronautiques est un enjeu majeur pour les motoristes. Afin de les accompagner dans cette tâche, il est nécessaire de développer des outils de simulation numérique permettant de prédire avec précision les émissions d'espèces chimiques en sortie du foyer. Pour cela, une description détaillée des réactions chimiques est nécessaire. Celle-ci est néanmoins incompatible avec la simulation des foyers industriels, compte tenu des puissances de calcul actuelles. C'est pourquoi il est nécessaire de recourir à des méthodes de réduction de la chimie qui préservent la capacité de prédire la concentration des polluants. La démarche consistant à tabuler la chimie nous a semblé appropriée pour aborder ces problèmes et son développement a fait l'objet de cette thèse. Un premier travail a été effectué afin de sélectionner dans la littérature les modèles permettant de traiter des écoulements réactifs turbulents diphasiques avec une approche de chimie tabulée. Par rapport à l’existant, des améliorations ont été apportées à la génération des tables chimiques, afin de prendre en compte l'effet du temps de résidence des gaz brûlés dans le foyer sur la formation des oxydes d'azote. Le couplage de la méthode avec un modèle de formation des suies a également été réalisé. La chimie tabulée permet d’avoir accès à la concentration des précurseurs de suie et des espèces oxydantes, quantités sur lesquelles s’appuie le modèle de formation des suies. Le modèle de chimie tabulée développé dans le cadre de cette thèse a été appliqué à la simulation d'une configuration représentative des foyers aéronautiques. Les concentrations d'oxydes d'azote, de particules de suie, mais aussi de monoxyde de carbone et d'hydrocarbures imbrûlés prédites par les calculs ont été comparées aux résultats expérimentaux. Un bon accord avec l'expérience est observé concernant la topologie du champ de suie et l'allure des profils de concentration de polluants en sortie. Néanmoins, les niveaux de concentration obtenus par les simulations diffèrent des résultats expérimentaux. Cela est imputable notamment à une erreur de prédiction du champ de température qui n'est pas due à l'approche de chimie-tabulée puisque une erreur similaire a été observée avec un autre modèle de combustion
The reduction of pollutant emissions of aeronautical combustion chambers is a major issue for engine manufacturers. In order to support them in this task, it is necessary to develop numerical simulation tools able to predict accurately chemical species emissions at the chamber outlet. To achieve this, a detailed description of the chemical reactions is necessary. Nevertheless, considering the current computer capabilities, this description is not presently affordable. This is why the use of chemistry reduction methods preserving the capability to predict pollutants species is necessary. The method of tabulated chemistry is a good candidate to tackle these problems and therefore is used as the basis of model developments achieved in the framework of this PhD thesis. A preliminary work has been made to select in the literature tabulated chemistry methods applying to turbulent reactive two-phase flows. The technique to create the chemical tables has been improved in order to take into account the effect of the residence time of the burnt gases on nitrogen oxides formation. The coupling of the method with a soot model has also been achieved. The tabulated chemistry gives access to the concentration of soot precursors and oxidizers, quantities which are required by the model used for the soot prediction. The developed tabulated chemistry model has been applied to the simulation of a configuration representative of aeronautical combustors. The concentration of nitrogen oxides, soot particles, carbon monoxide and unburnt hydrocarbons predicted by the numerical simulations have been compared to experimental results. The topology of the soot volume fraction field and the shape of pollutant concentrations profiles at the outlet agree quite well with the experiments. Nevertheless, concentration levels obtained from the simulations differ from the experimental results. This can be imputed to the error in the prediction of the temperature field that is independent of the combustion model, since a similar error was observed with another combustion model

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Santos, Rodrigo Fernando Estella dos. « Análise experimental do desempenho e da combustão de um motor de ignição por compressão alimentado por uma mistura ternária de combustíveis : diesel, biodiesel e etanol ». Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/18/18135/tde-01022016-151906/.

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É analisado o desempenho de um motor de ignição por compressão turboalimentado por uma mistura temária de combustíveis (diesel, biodiesel e etanol) através do comportamento do motor operando com um combustível principal, o qual poderá ser o diesel ou biodiesel ou misturas destes dois, com e sem sua substituição parcial por etanol no coletor de admissão. A análise do desempenho é feita através das curvas de torque, potência, rendimento térmico e consumo específico de combustível. A combustão do motor é estudada através de um programa simulador que utiliza um modelo zero-dimensional, que avalia a taxa de liberação de calor durante a combustão e tem como dado de entrada a curva de evolução da pressão dentro do cilindro. Faz-se a identificação e quantificação do fenômeno da detonação utilizando análise espectral, através do sinal de pressão da câmara de combustão, para o motor operando com diversas misturas combustíveis. São analisadas também as emissões gasosas do motor com as misturas, e a viabilidade técnica do uso de biodiesel em motores de ignição por compressão, além de um estudo geral sobre o uso do éster de óleo vegetal.
The performance of a three-fuel system (diesel, biodiesel and ethanol) turbocharged compression-ignition engine is analyzed, through the engine behavior supplied by mixtures of diesel or biodiesel or mixtures of these fuels with ethanol in the intake manifold. The performance analysis is made by torque, power, specific fuel consumption and thermal efficiency curves. The engine combustion is studied by a simulator program that uses a zero-dimensional model, that evaluate the heat release rate during the combustion and it has as input data the pressure evolution curves inside the cylinder. The knocking phenomenon is studied by spectral analysis. The pollutant gases emissions and the technical viability of the utilization of biodiesel also are analyzed, beyond a general study about of vegetal oil ester.

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Vinay, Kumar Nerella V. « An Analysis on Vehicular Exhaust Emissions from Transit Buses Running on Biodiesel Blends ». University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1271886446.

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Al, Hamrani Emad, et Nils Grönberg. « Sustainable flue-gas quench : For waste incineration plants within a water-energy-environment nexus perspective ». Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-36707.

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The function of a flue-gas quench is to remove additional contaminants from flue-gas and to reduce the wastewater from a waste incineration plant. The aim of this degree project is to find how the system is affected by using a quench and what factors limits the performance. This is done by modelling and simulating a waste incineration plant in Aspen Plus. Data and plant schematics were obtained by a study visit to Mälarenergi Plant 6 situated in Västerås, Sweden, which were used as model input and for model validation. The results have shown that the amount of wastewater can be reduced by more than half compared to a plant without a quench. The heat produced in the condenser, when discharging water to the boiler, would be lowered by up to 20%. For systems with a quench present when more water was discharged to the boiler both the heat production and the pollutant capturing became better. However, the system has limits regarding the amount that could be recirculated, in the form of temperature limits in different parts of the system. In addition, if the heat load is low there is an insufficient amount of wastewater generated in the condenser to run the quench. In that situation, clean (fresh) water needs to be used instead. Using clean water is unwanted since the plant will then consume more resources while still producing less heat than a plant without a quench would.

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Thèses sur le sujet « Emissions of pollutant »

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