Publication: EVALUACIÓN DE LA PRODUCCIÓN DE HIDRÓGENO A PARTIR DE BIOGÁS PROVENIENTE DE BIODIGESTORES ANAERÓBICOS DE RESIDUOS AGROINDUSTRIALES CON INYECCIÓN DE VAPOR DE AGUA
Date
2018
Authors
ESPINOZA AGUIRRE, LORENA PAZ
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Abstract
En Chile, sólo el 14 % del potencial energético disponible a partir de la metanización de residuos orgánicos es utilizado como fuente de energía primaria. La industria silvoagropecuaria nacional debe lidiar con una multiplicidad de residuos de alto contenido orgánico que requieren de tratamiento, previa disposición final. Como alternativa, la digestión anaerobia permite reducir la carga contaminante del desecho, obteniendo como principal producto biogás (CH4/CO2). Éste, pese a ser utilizado como combustible, posee una alta concentración de CO2 que reduce de forma importante su potencial energético, disminuyendo además la estabilidad de la combustión. En este sentido, el reformado no-catalítico de biogás en reactores de medios porosos inertes, representa una alternativa que eleva la densidad energética del biogás al transformarlo en vector energético en la forma de gas de síntesis (H2/CO).En esta línea, el presente trabajo expone resultados empíricos sobre la generación de H2 y gas de síntesis a partir de la combustión filtrada de biogás, como método no-catalítico de valorización que además favorezca la producción de biometano en digestores anaerobios. Se considera la combustión de mezclas de biogás/aire con una fracción volumétrica GN/CO2 de 1,5 [-] y una velocidad de filtración de 34,4 [cm s-1]. Registros de temperatura y velocidad del frente de llama, y concentración de gases producto se obtuvieron para relaciones de equivalencia (fi) y vapor-combustible (S/C) variables. Se observa que la inyección de vapor de agua en reactivos favorece mecanismos de reformado húmedo, particularmente para mezclas ultra-ricas, registrándose un óptimo de 10,34 %vol H2 y 9,98 %vol CO con una eficiencia térmica de reformado de 64,2 %, para una mezcla compuesta por 56 %vol aire, 24 %vol H2O, 12 %vol GN y 8 %vol CO2, asociada a un fi=2,0 [-] y un S/C=2,0 [-].
In Chile, only 14 % of the potential energy available from organic waste methanization is used as primary energy source. National agroforestry industry must deal with multiple kind of wastes of high organic content that require treatment before final disposal. As an alternative, anaerobic digestion of the waste can reduce its polluting load and produce biogas (CH4/CO2) as a main result, which, despite of being able to be used directly as a fuel, its high CO2 content reduces significantly its energy potential, thus, affecting the stability of combustion processes. In this sense, non-catalytic reforming of biogas in inert porous media reactors represents a valorization alternative to improve the energy density of biogas by converting it into an energy vector in the form of syngas (H2/CO).Accordingly, empirical results for H2 and syngas production from filtration combustion of biogas, as a non-catalytic method of valorization, which could also favor biomethane production in anaerobic digesters, are presented in this work. Experiments on combustion of biogas/air admixtures were conducted at a NG/CO2 volumetric fraction of 1,5 [-] and a filtration velocity of 34,4 [cm s-1]. Temperature acquisition, flame front velocity and product gas compositions were recorded for variable equivalence ratios (phi) and Steam/Carbon fractions (S/C). Results evidenced that co-injection of steam in reagents favored the steam reforming mechanisms, particularly for ultra-rich admixtures, reporting an optimum of 10,34 vol % H2 and 9,98 vol% CO with a thermal efficiency of 64,2 %, for an admixture with 56 vol % air, 24 vol % H2O, 12 vol % NG, and 8 vol % CO2, associated to a phi = 2,0 [-] and S/C = 2,0 [-].
In Chile, only 14 % of the potential energy available from organic waste methanization is used as primary energy source. National agroforestry industry must deal with multiple kind of wastes of high organic content that require treatment before final disposal. As an alternative, anaerobic digestion of the waste can reduce its polluting load and produce biogas (CH4/CO2) as a main result, which, despite of being able to be used directly as a fuel, its high CO2 content reduces significantly its energy potential, thus, affecting the stability of combustion processes. In this sense, non-catalytic reforming of biogas in inert porous media reactors represents a valorization alternative to improve the energy density of biogas by converting it into an energy vector in the form of syngas (H2/CO).Accordingly, empirical results for H2 and syngas production from filtration combustion of biogas, as a non-catalytic method of valorization, which could also favor biomethane production in anaerobic digesters, are presented in this work. Experiments on combustion of biogas/air admixtures were conducted at a NG/CO2 volumetric fraction of 1,5 [-] and a filtration velocity of 34,4 [cm s-1]. Temperature acquisition, flame front velocity and product gas compositions were recorded for variable equivalence ratios (phi) and Steam/Carbon fractions (S/C). Results evidenced that co-injection of steam in reagents favored the steam reforming mechanisms, particularly for ultra-rich admixtures, reporting an optimum of 10,34 vol % H2 and 9,98 vol% CO with a thermal efficiency of 64,2 %, for an admixture with 56 vol % air, 24 vol % H2O, 12 vol % NG, and 8 vol % CO2, associated to a phi = 2,0 [-] and S/C = 2,0 [-].
Description
Catalogado desde la version PDF de la tesis.
Keywords
GAS DE SINTESIS , MEDIOS POROSOS INERTER , PRODUCCION DE HIDROGENO , REFORMADO DE BIOGAS