Modelación de un gasificador de biomasa de tiro descendente para la producción de un combustible sostenible de aviación.
Loading...
Date
2024
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Universidad de Concepción
Abstract
En Chile, la mayoría de los residuos forestales generados en terrenos de plantación son gestionados de forma ineficiente, siendo quemados ocasionando significativos impactos ambientales. Aunque no se logró cuantificar con precisión la cantidad de residuos disponibles en terreno, este estudio se centró en los residuos provenientes de la industria del aserrío. A nivel nacional, el 1.03% de estos residuos corresponde subproductos destinados a regalar, el 1% a residuos acumulados, mientras que el 98% restante es destinado a autoconsumo y comercialización. Como alternativa para valorizar estos residuos, esta investigación propone su gasificación como una estrategia para producir un gas de síntesis apto para la generación de biocombustibles sostenibles para aviación.
El objetivo principal de esta investigación es modelar un sistema de gasificación de biomasa en un gasificador de corriente descendente, evaluando su viabilidad técnica, económica y ambiental con el propósito de contribuir a la descarbonización del sector aeronáutico. La hipótesis plantea que el uso de un gasificador de corriente descendente incrementa la eficiencia de conversión del carbono, produciendo un gas con un alto contenido de hidrógeno y monóxido de carbono, lo cual es favorable para la síntesis de combustibles sostenibles mediante el proceso Fischer-Tropsch.
Para abordar este objetivo, se desarrollaron y evaluaron cuatro modelos basados en un enfoque de equilibrio termodinámico no estequiométrico. El modelo M1 es un modelo de equilibrio no estequiométrico puro, el modelo M2 posee una restricción en el contenido de metano, el modelo M3 considera una restricción cinética que determina la tasa de gasificación aparente y finalmente las dos restricciones mencionadas anteriormente se implementan juntas en el modelo M4.
Los resultados indicaron que los modelos M2 y M4 presentaron la mayor precisión, con un error normalizado medio cuadrático (NRMSE) promedio de 0.08 cada uno. Tras validar los modelos utilizando datos experimentales reportados en la literatura, se aplicaron al estudio de la gasificación de aserrín de pino en un gasificador de corriente descendente utilizando aire como agente gasificador. Los análisis mostraron que, bajo condiciones operativas de tiempo de gasificación superior a 30 minutos, relación de equivalencia (ER) de 0.32 y contenido de humedad (MC) del 10%, se alcanzan eficiencias de conversión del carbono mayores al 90%.
Se realizó un análisis económico y ambiental preliminar que demostró la viabilidad de implementar un sistema de gasificación, evidenciando tanto beneficios económicos como ambientales. Sin embargo, este análisis se limitó exclusivamente a la etapa de gasificación. Para obtener una evaluación más completa, es necesario incorporar el proceso de síntesis de Fischer-Tropsch, lo que permitiría un análisis económico y ambiental más detallado y verificará si el biocombustible producido cumple con los requerimientos técnicos, económicos y normativos del sector aeronáutico.
In Chile, most of the forest residues generated on plantation lands are inefficiently managed and burned, causing significant environmental impacts. Although it was not possible to precisely quantify the amount of waste available on the ground, this study focused on waste from the sawmill industry. At the national level, 1.03% of this waste corresponds to by-products destined to be given away, 1% to accumulated waste, while the remaining 98% is destined for self-consumption and commercialization. As an alternative to valorize these wastes, this research proposes their gasification as a strategy to produce a synthesis gas suitable for the generation of sustainable biofuels for aviation. The main objective of this research is to model a biomass gasification system in a downdraft gasifier, evaluating its technical, economic and environmental feasibility with the purpose of contributing to the decarbonization of the aeronautical sector. The hypothesis states that the use of a downdraft gasifier increases the carbon conversion efficiency, producing a gas with a high content of hydrogen and carbon monoxide, which is favorable for the synthesis of sustainable fuels through the Fischer-Tropsch process. To address this objective, four models based on a non-stoichiometric thermodynamic equilibrium approach were developed and evaluated. Model M1 is a pure non-stoichiometric equilibrium model, model M2 has a constraint on the methane content, model M3 considers a kinetic constraint that determines the apparent gasification rate and finally the two constraints are implemented together in model M4. The results indicated that the M2 and M4 models presented the highest accuracy, with an average normalized root mean square error (NRMSE) of 0.08 each. After validating the models using experimental data reported in the literature, they were applied to the study of pine sawdust gasification in a downdraft gasifier using air as the gasifying agent. The analyses showed that, under operating conditions of gasification time greater than 30 minutes, equivalence ratio (ER) of 0.32 and moisture content (MC) of 10%, carbon conversion efficiencies greater than 90% are achieved. A preliminary economic and environmental analysis was conducted that demonstrated the feasibility of implementing a gasification system, showing both economic and environmental benefits. However, this analysis was limited exclusively to the gasification stage. To obtain a more complete evaluation, it is necessary to incorporate the Fischer-Tropsch synthesis process, which would allow a more detailed economic and environmental analysis and will verify whether the biofuel produced meets the technical, economic and regulatory requirements of the aeronautical sector.
In Chile, most of the forest residues generated on plantation lands are inefficiently managed and burned, causing significant environmental impacts. Although it was not possible to precisely quantify the amount of waste available on the ground, this study focused on waste from the sawmill industry. At the national level, 1.03% of this waste corresponds to by-products destined to be given away, 1% to accumulated waste, while the remaining 98% is destined for self-consumption and commercialization. As an alternative to valorize these wastes, this research proposes their gasification as a strategy to produce a synthesis gas suitable for the generation of sustainable biofuels for aviation. The main objective of this research is to model a biomass gasification system in a downdraft gasifier, evaluating its technical, economic and environmental feasibility with the purpose of contributing to the decarbonization of the aeronautical sector. The hypothesis states that the use of a downdraft gasifier increases the carbon conversion efficiency, producing a gas with a high content of hydrogen and carbon monoxide, which is favorable for the synthesis of sustainable fuels through the Fischer-Tropsch process. To address this objective, four models based on a non-stoichiometric thermodynamic equilibrium approach were developed and evaluated. Model M1 is a pure non-stoichiometric equilibrium model, model M2 has a constraint on the methane content, model M3 considers a kinetic constraint that determines the apparent gasification rate and finally the two constraints are implemented together in model M4. The results indicated that the M2 and M4 models presented the highest accuracy, with an average normalized root mean square error (NRMSE) of 0.08 each. After validating the models using experimental data reported in the literature, they were applied to the study of pine sawdust gasification in a downdraft gasifier using air as the gasifying agent. The analyses showed that, under operating conditions of gasification time greater than 30 minutes, equivalence ratio (ER) of 0.32 and moisture content (MC) of 10%, carbon conversion efficiencies greater than 90% are achieved. A preliminary economic and environmental analysis was conducted that demonstrated the feasibility of implementing a gasification system, showing both economic and environmental benefits. However, this analysis was limited exclusively to the gasification stage. To obtain a more complete evaluation, it is necessary to incorporate the Fischer-Tropsch synthesis process, which would allow a more detailed economic and environmental analysis and will verify whether the biofuel produced meets the technical, economic and regulatory requirements of the aeronautical sector.
Description
Tesis presentada para optar al título profesional de Ingeniera Civil Aeroespacial
Keywords
Biomasa, Sustentabilidad, Combustibles Investigaciones