Publication: DETERMINACIÓN DEL POTENCIAL CONTAMINANTE Y TOXICOLÓGICO DE EMISIONES PRODUCIDAS POR COMBUSTIBLES FÓSILES Y BIOCOMBUSTIBLES DE INTERÉS NACIONAL
Date
2019
Authors
PLACENCIA LOBOS, FABIÁN ANDRÉS
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
La inserción de los biocombustibles, en particular el biodiésel, a la matriz energética nacional obedece a la necesidad de abastecer y dar sustentabilidad al suministro energético, dar cumplimiento a compromisos internacionales para disminuir el calentamiento global y generar una economía menos dependiente del petróleo fósil. La presente Tesis doctoral tuvo como objetivo evaluar el impacto toxicológico de las emisiones reguladas y no reguladas, generadas por biocombustibles que puedan insertarse en el mercado nacional, respecto a su origen y proporción de mezcla con combustibles fósiles (diésel) en un vehículo representativo de la flota vehicular chilena.
Para conseguir los objetivos de la tesis se emplearon una gran diversidad de técnicas de medición de contaminantes en tiempo real y en laboratorio. Para ello se hizo uso de una camioneta Mitsubishi Katana L-200 montada sobre un dinamómetro de chasis con túnel de dilusión, bajo el Nuevo Ciclo de Conducción Europeo (NEDC). Los compuestos analizados en tiempo real fueron; CO, CO2 NOx, hidrocarburos totales, black carbon y partículas. Mientras que las muestras de hidrocarburos aromáticos policíclicos (HAPs), en fase gaseosa y particulada, junto con los carbonilos fueron analizados en laboratorio mediante la cuantificación por cromatografía de gases con espectrometría de masas (GC-MS) para HAPs y cromatografía líquida de alta resolución (HPLC) para carbonilos. La evaluación toxicológica se realizó de manera teórica (BaP equivalente y Pontencial formador de ozono), y de manera experimental exponiendo in situ y en vivo al biomonitor Tradescantia a las emisiones vehiculares, mediante los ensayos de micronúcleos (TradMCN) y de pelos estaminales (TradSH).
Los resultados más relevantes de la presente tesis, confirman una disminución significativa de las emisiones de hidrocarburos totales, PM10, PM2.5, PM1 y Black carbon con el empleo de todos los biocombustibles (entre un 80-90% de disminución con el uso de B80). Las emisiones de NOx, se incrementaron durante las fases de mayor carga de motor (ciclo extraurbano) siendo el biodiésel de soya al 80% (B80) el que presentó el mayor incremento de NOx. Estos comportamientos de las emisiones se asociaron al mayor aporte de oxígeno del biocombustible y a un desplazamiento del tiempo de combustión por las diferencias entre sus propiedades físicas, en particular su viscosidad. En las emisiones de carbonilos, el formaldehído fue el principal compuesto emitido. presentando un incremento con el uso de biodiésel, siendo el biodiésel de aceite de soya y biodiésel de aceite de palma los de mayor y menor porcentaje de oxígeno respectivamente. Este incremento de las emisiones de carbonilos produjo un incremento significativo del factor de formación de ozono, en especial para biodiésel de grasa animal, cuyo valor se dispara con B80 debido a un fuerte incremento de acetaldehído durante los ensayos. Los resultados de especiación de hidrocarburos aromáticos policíclicos (HAPs), indican que para emisiones de HAPs gaseosos el compuesto más abundante fue naftaleno (NAP), siendo biodiésel de palma el que entregó la mayor emisión y biodiésel de aceite de soya, la menor emisión. En fase partícula, la predominancia de los HAPs fueron pireno (PYR), fluoranteno (FLT) y antraceno (ANT). De acuerdo con los análisis realizados se determinó que el biodiésel de palma fue el que presento una menor cantidad de impurezas y el menor contenido de insaturaciones (cadenas con dobles enlaces), mientras que el biodiésel de soya fue el que presentó mayor contenido de dobles enlaces debido a su rico contenido de metil ester de ácido linoleico y linolénico, estableciéndose una propuesta de mecanismo de formación de HAPs para metíl esteres saturados e insaturados. Otro punto relevante de las emisiones de HAPs en fase partícula, fueron los resultados de las proporciones diagnósticas moleculares (MDR). Estos indican que fenantreno, criseno, antraceno, fluoranteno y prieno, son los marcadores moleculares importantes para las emisiones de combustión diésel y biodiésel, permitiendo asociar nuestros resultados con el de otros autores, quienes hallaron proporciones similares.
Finalmente, la evaluación toxicológica de las emisiones a través de los biomonitores indican un efecto mutagénico similar para casi todas las mezclas evaluadas (B80), siendo el biodiésel de aceite de palma el único que reporto efectos de disminución en su toxicidad con los ensayos de pelos estaminales y micronúcleos, en comparación al biomonitor expuesto a diésel. Los análisis de clúster realizados entre las emisiones de los biocombustibles y los resultados de mutagenicidad revelan que los efectos tóxicos dependen principalmente de los PAHs en fase gaseosa y los carbonilos presentes en los gases de escape. Sin embargo, los resultados teóricos de toxicidad mencionados anteriormente para los PAHs en fase partícula, no descartan su importancia toxicológica.
Como conclusiones de toda la información generada, se comprueba que los biodiéseles producen una disminución significativa de una serie de contaminantes y del potencial toxicológico de sus emisiones, desechando la hipótesis original de la tesis (la cual apostaba por un mayor incremento de la mutagenicidad), pero aporta mayor relevancia, ya que la implementación de mayores porcentajes de biodiésel sin un aumento significativo de la toxicidad permite a las autoridades modificar la legislación, incrementando el porcentaje de biodiésel permitido por ley y tomando en consideración la pureza (calidad) y composición química (saturación) del biocombustible (tomando como ejemplo, el biodiésel de palma en un 20%).
The insertion of biofuels, in particular biodiesel, into the national energy matrix is due to the need to supply and sustain energy supply, to comply with international commitments to reduce global warming and generate an economy less dependent on fossil oil. The objective of this PhD Thesis was to evaluate the toxicological impact of regulated and unregulated emissions, generated by biofuels that can be inserted in the national market, with respect to their origin and proportion of mixture with fossil fuels (diesel) in a vehicle representative of the Chilean vehicular fleet. To achieve the objectives of the thesis, a wide variety of techniques for measuring pollutants were used in real time and in the laboratory. For this purpose, a Mitsubishi Katana L-200 truck was used, mounted on a chassis dynamometer with a dilution tunnel, under the New European Driving Cycle (NEDC). The compounds analyzed in real time were; CO, CO2 NOx, total hydrocarbons, black carbon and particles. While samples of polycyclic aromatic hydrocarbons (PAHs), in gaseous and particulate phase, together with carbonyls were analyzed in the laboratory by quantification by gas chromatography with mass spectrometry (GC-MS) for HAPs and high performance liquid chromatography (HPLC) for carbonyls. The toxicological evaluation was carried out in a theoretical manner (BaP equivalent and Pontencial ozone maker), and experimentally exposing in situ and in vivo the Tradescantia biomonitor to vehicular emissions, through the tests of micronuclei (TradMCN) and of stem hairs (TradSH ). The most relevant results of this thesis confirm a significant decrease in total hydrocarbon emissions, PM10, PM2.5, PM1 and Black carbon with the use of all biofuels (between 80-90% decrease with the use of B80). NOx emissions increased during the phases of higher engine load (extra-urban cycle) with 80% soybean biodiesel (B80) having the highest increase in NOx. These behaviors of the emissions were associated to the greater contribution of oxygen of the biofuel and to a displacement of the combustion time due to the differences between its physical properties, in particular its viscosity. In carbonyl emissions, formaldehyde was the main compound emitted. presenting an increase with the use of biodiesel, being the biodiesel from soybean oil and biodiesel from palm oil those with the highest and lowest percentage of oxygen respectively. This increase in carbonyl emissions produced a significant increase in the ozone formation factor, especially for animal fat biodiesel, whose value is triggered by B80 due to a strong increase in acetaldehyde during the tests. The speciation results of polycyclic aromatic hydrocarbons (PAHs), indicate that for emissions of gaseous PAHs the most abundant compound was naphthalene (NAP), being palm biodiesel the one that delivered the highest emission and biodiesel from soybean oil, the lowest emission. In the particle phase, the predominance of PAHs were pyrene (PYR), fluoranthene (FLT) and anthracene (ANT). According to the analyzes carried out, it was determined that the palm biodiesel was the one with the least amount of impurities and the lowest content of unsaturations (chains with double bonds), while soybean biodiesel was the one with the highest content of double bonds. due to its rich content of linoleic acid and linolenic acid methyl ester, establishing a proposal for the mechanism of formation of PAHs for saturated and unsaturated methyl esters. Another relevant point of the emissions of PAHs in the particle phase, were the results of the molecular diagnostic proportions (MDR). These indicate that phenanthrene, chrysene, anthracene, fluoranthene and priene, are the important molecular markers for diesel and biodiesel combustion emissions, allowing us to associate our results with that of other authors, who found similar proportions. Finally, the toxicological evaluation of the emissions through the biomonitors indicate a similar mutagenic effect for almost all of the mixtures evaluated (B80), with palm oil biodiesel being the only one that reported diminishing effects on its toxicity with hair tests. staminales and micronuclei, in comparison to the biomonitor exposed to diesel. Cluster analyzes carried out between biofuel emissions and mutagenicity results reveal that the toxic effects mainly depend on the gas phase PAHs and the carbonyls present in the exhaust gases. However, the theoretical toxicity results mentioned above for particle phase PAHs do not rule out their toxicological importance. As conclusions of all the information generated, it is verified that the biodiesels produce a significant decrease of a series of pollutants and the toxicological potential of their emissions, discarding the original hypothesis of the thesis (which bet for a greater increase in mutagenicity), but it is more relevant, since the implementation of higher percentages of biodiesel without a significant increase in toxicity allows the authorities to modify the legislation, increasing the percentage of biodiesel allowed by law and taking into consideration the purity (quality) and chemical composition ( saturation) of the biofuel (taking as an example, the palm biodiesel by 20%).
The insertion of biofuels, in particular biodiesel, into the national energy matrix is due to the need to supply and sustain energy supply, to comply with international commitments to reduce global warming and generate an economy less dependent on fossil oil. The objective of this PhD Thesis was to evaluate the toxicological impact of regulated and unregulated emissions, generated by biofuels that can be inserted in the national market, with respect to their origin and proportion of mixture with fossil fuels (diesel) in a vehicle representative of the Chilean vehicular fleet. To achieve the objectives of the thesis, a wide variety of techniques for measuring pollutants were used in real time and in the laboratory. For this purpose, a Mitsubishi Katana L-200 truck was used, mounted on a chassis dynamometer with a dilution tunnel, under the New European Driving Cycle (NEDC). The compounds analyzed in real time were; CO, CO2 NOx, total hydrocarbons, black carbon and particles. While samples of polycyclic aromatic hydrocarbons (PAHs), in gaseous and particulate phase, together with carbonyls were analyzed in the laboratory by quantification by gas chromatography with mass spectrometry (GC-MS) for HAPs and high performance liquid chromatography (HPLC) for carbonyls. The toxicological evaluation was carried out in a theoretical manner (BaP equivalent and Pontencial ozone maker), and experimentally exposing in situ and in vivo the Tradescantia biomonitor to vehicular emissions, through the tests of micronuclei (TradMCN) and of stem hairs (TradSH ). The most relevant results of this thesis confirm a significant decrease in total hydrocarbon emissions, PM10, PM2.5, PM1 and Black carbon with the use of all biofuels (between 80-90% decrease with the use of B80). NOx emissions increased during the phases of higher engine load (extra-urban cycle) with 80% soybean biodiesel (B80) having the highest increase in NOx. These behaviors of the emissions were associated to the greater contribution of oxygen of the biofuel and to a displacement of the combustion time due to the differences between its physical properties, in particular its viscosity. In carbonyl emissions, formaldehyde was the main compound emitted. presenting an increase with the use of biodiesel, being the biodiesel from soybean oil and biodiesel from palm oil those with the highest and lowest percentage of oxygen respectively. This increase in carbonyl emissions produced a significant increase in the ozone formation factor, especially for animal fat biodiesel, whose value is triggered by B80 due to a strong increase in acetaldehyde during the tests. The speciation results of polycyclic aromatic hydrocarbons (PAHs), indicate that for emissions of gaseous PAHs the most abundant compound was naphthalene (NAP), being palm biodiesel the one that delivered the highest emission and biodiesel from soybean oil, the lowest emission. In the particle phase, the predominance of PAHs were pyrene (PYR), fluoranthene (FLT) and anthracene (ANT). According to the analyzes carried out, it was determined that the palm biodiesel was the one with the least amount of impurities and the lowest content of unsaturations (chains with double bonds), while soybean biodiesel was the one with the highest content of double bonds. due to its rich content of linoleic acid and linolenic acid methyl ester, establishing a proposal for the mechanism of formation of PAHs for saturated and unsaturated methyl esters. Another relevant point of the emissions of PAHs in the particle phase, were the results of the molecular diagnostic proportions (MDR). These indicate that phenanthrene, chrysene, anthracene, fluoranthene and priene, are the important molecular markers for diesel and biodiesel combustion emissions, allowing us to associate our results with that of other authors, who found similar proportions. Finally, the toxicological evaluation of the emissions through the biomonitors indicate a similar mutagenic effect for almost all of the mixtures evaluated (B80), with palm oil biodiesel being the only one that reported diminishing effects on its toxicity with hair tests. staminales and micronuclei, in comparison to the biomonitor exposed to diesel. Cluster analyzes carried out between biofuel emissions and mutagenicity results reveal that the toxic effects mainly depend on the gas phase PAHs and the carbonyls present in the exhaust gases. However, the theoretical toxicity results mentioned above for particle phase PAHs do not rule out their toxicological importance. As conclusions of all the information generated, it is verified that the biodiesels produce a significant decrease of a series of pollutants and the toxicological potential of their emissions, discarding the original hypothesis of the thesis (which bet for a greater increase in mutagenicity), but it is more relevant, since the implementation of higher percentages of biodiesel without a significant increase in toxicity allows the authorities to modify the legislation, increasing the percentage of biodiesel allowed by law and taking into consideration the purity (quality) and chemical composition ( saturation) of the biofuel (taking as an example, the palm biodiesel by 20%).
Description
Keywords
BIODIESEL , BLACK CARBON , GENOTOXICIDAD , EMISIONES VEHICULARES , HIDROCARBUROES AROMATICOS POLICICLICOS , NUEVA CAMARA DE EXPOSICION