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Abstract(s)
Las constantes preocupaciones sobre el cambio climático y el calentamiento global,
producido por las emisiones de dióxido de carbono asociadas al uso de combustibles fósiles,
convirtieron el hidrogeno en el principal vector energético del futuro inmediato debido a que
es el único combustible que se puede producir de un recurso renovable tan abundante como el
agua y cuyo producto de combustión es únicamente agua. Al contrario que los hidrocarburos,
no puede ser destruido, sino que simplemente cambia de estado, siendo una buena opción para
reducir las emisiones de gases de efecto invernadero. Se conocen cuatro grandes categorías de
métodos de síntesis que producen hidrógeno: biológica, química, electroquímica y tecnologías
térmicas. En este proyecto se optó por trabajar con el método de síntesis electroquímica,
concretamente en la electrolisis del agua que representa el 4% de la producción mundial de
hidrógeno y que comparado con otros métodos, tiene la ventaja de producir hidrógeno
extremadamente puro (> 99.9%) y no emite contaminantes ni gases de efecto invernadero ya
que el producto de su combustión es solo agua.
En este proyecto se diseñó, proyecto y construyo una célula para la electrolisis alcalina
del agua, con el objetivo de conseguir producir gas de Brown para ser utilizado, en un futuro,
como combustible en un motor de combustión interna.
Para conseguir producir gas de Brown, se utilizó como electrolito una solución acuosa
de hidróxido de potasio (KOH≈ 1𝑚𝑜𝑙/𝐿). Se establecieron como parámetros fijos la
distancia entre electrodos (15 mm), el volumen de electrolito (VKOH=160 mL), el tiempo de
medición de producción de gas.
Se estudió la producción de gas Brown utilizando electrodos de dos materiales
diferentes, uno de referencia de estudios anteriores, el acero inoxidable 304 L y otro material
nuevo, el acero inoxidable 420 MC. Se estudió el efecto de un tratamiento de decapado en los
electrodos, usando ácido clorhídrico (HCl≈ 1𝑚𝑜𝑙/𝐿) y ácido nítrico (HNO3 al 5%), en la
producción de gas. Se determinó el consumo de electrolito durante el proceso de electrólisis y
se evaluó el efecto de la intensidad de corriente en el aumento o disminución de la producción de gas, trabajando con tres intensidades de corriente diferentes 1, 2 y 3 amperios. Finalmente
se realizó un estudio de la influencia de la porosidad y la rugosidad del metal en la producción
de gas de Brown.
Se concluyó que el aumento de la intensidad de corriente provoca un aumento en la
producción de gas de Brown. El acero 304 L y el acero 420 MC tienen un comportamiento
similar en lo que se refiere al volúmen de producción de gas de Brown, pero el acero 420 MC
no se recomienda en este tipo de procesos electroquímicos porque libera óxido durante el
proceso de electrolisis contaminando el electrolito (KOH). No se recomienda realizar un
tratamiento de decapado ya que no produce mejoras en la producción de gas y debilita el
material del electrodo disminuyendo su vida útil. El consumo de electrolito (KOH) no
representa un problema, ya que se obtuvieron valores muy bajos de consumo durante los
ensayos de electrolisis. Se determinó que el aumento de la rugosidad en la superficie del
electrodo facilita el desprendimiento de las burbujas de gas aumentando la producción de gas
y se comprobó que a medida que aumenta la porosidad en la superficie del acero, aumenta el
área útil del metal a través de la formación de cavidades que favorecen un aumento en la
producción de gas de Brown, ya que se dispone de una superficie mayor.
The constant concerns about climate change and global warming, produced by carbon dioxide emissions associated with the use of fossil fuels, turned hydrogen into the main energy vector of the immediate future because it is the only fuel that can be produced from a renewable resource as abundant as water and whose combustion product is only water. Unlike hydrocarbons, it can not be destroyed but simply changes its status, being a good option to reduce greenhouse gas emissions. There are four main synthesis methods toproduce hydrogen: Biological, chemical, electrochemical and thermal technologies. In this project we focus on the electrochemical synthesis method, specifically in the electrolysis of water, which represents 4% of the world's hydrogen production and which, compared to other methods, has the advantage of producing extremely pure hydrogen (> 99.9%) and it does not emit pollutants or greenhouse gases since the product of its combustion is only water. In this project, was designed, projected and built an alkaline water electrolysis cell, with the aim of producing Brown gas to be used, in the future, as fuel in an internal combustion engine. In order to produce Brown's gas, a solution of potassium hydroxide (KOH≈1mol/L) was used as the electrolyte. The distance between electrodes (15 mm), the volume of electrolyte (VKOH = 160 mL), the measurement time of gas production were established as fixed parameters. The Brown gas production of two types of electrodes of different materials was studied, one of reference of previous studies, the stainless steel 304 L and another new material, the stainless steel 420 MC. The effect of a pickling treatment on the electrodes was studied, using hydrochloric acid (HCl≈1 mol/L) and nitric acid (5% HNO3), in gas production. The electrolyte consumption was determined during the electrolysis process and the effect of current intensity on the increase or decrease of the gas production was evaluated, working with three different currents 1, 2 and 3 amperes. Finally, a study of the influence of the porosity and the roughness of the metal in Brown's gas production was made. It was verified that the increase in current intensity causes an increase in Brown's gas production. Steel 304 L and steel 420 MC have a similar behavior regarding to Brown's gas production, but 420 MC steel is not recommended in this type of electrochemical processes because it releases rust during the electrolysis process, contaminating the electrolyte (KOH). It is not recommended to perform a pickling treatment as it does not produce improvements in gas production and weakens the material of the electrode, decreasing its useful life. The consumption of electrolyte (KOH) is not a problem, since very low consumption values were obtained during the electrolysis tests. It was determined that the increase in roughness at the surface of the electrode facilitates the release of gas bubbles by increasing gas production and it was found that as the porosity on the surface of the steel increases, the useful area of the metal increases because the formation of cavities that favor an increase in Brown's gas production, since a larger area is available.
The constant concerns about climate change and global warming, produced by carbon dioxide emissions associated with the use of fossil fuels, turned hydrogen into the main energy vector of the immediate future because it is the only fuel that can be produced from a renewable resource as abundant as water and whose combustion product is only water. Unlike hydrocarbons, it can not be destroyed but simply changes its status, being a good option to reduce greenhouse gas emissions. There are four main synthesis methods toproduce hydrogen: Biological, chemical, electrochemical and thermal technologies. In this project we focus on the electrochemical synthesis method, specifically in the electrolysis of water, which represents 4% of the world's hydrogen production and which, compared to other methods, has the advantage of producing extremely pure hydrogen (> 99.9%) and it does not emit pollutants or greenhouse gases since the product of its combustion is only water. In this project, was designed, projected and built an alkaline water electrolysis cell, with the aim of producing Brown gas to be used, in the future, as fuel in an internal combustion engine. In order to produce Brown's gas, a solution of potassium hydroxide (KOH≈1mol/L) was used as the electrolyte. The distance between electrodes (15 mm), the volume of electrolyte (VKOH = 160 mL), the measurement time of gas production were established as fixed parameters. The Brown gas production of two types of electrodes of different materials was studied, one of reference of previous studies, the stainless steel 304 L and another new material, the stainless steel 420 MC. The effect of a pickling treatment on the electrodes was studied, using hydrochloric acid (HCl≈1 mol/L) and nitric acid (5% HNO3), in gas production. The electrolyte consumption was determined during the electrolysis process and the effect of current intensity on the increase or decrease of the gas production was evaluated, working with three different currents 1, 2 and 3 amperes. Finally, a study of the influence of the porosity and the roughness of the metal in Brown's gas production was made. It was verified that the increase in current intensity causes an increase in Brown's gas production. Steel 304 L and steel 420 MC have a similar behavior regarding to Brown's gas production, but 420 MC steel is not recommended in this type of electrochemical processes because it releases rust during the electrolysis process, contaminating the electrolyte (KOH). It is not recommended to perform a pickling treatment as it does not produce improvements in gas production and weakens the material of the electrode, decreasing its useful life. The consumption of electrolyte (KOH) is not a problem, since very low consumption values were obtained during the electrolysis tests. It was determined that the increase in roughness at the surface of the electrode facilitates the release of gas bubbles by increasing gas production and it was found that as the porosity on the surface of the steel increases, the useful area of the metal increases because the formation of cavities that favor an increase in Brown's gas production, since a larger area is available.
Description
Keywords
Electrolisis alcalina del agua Gas de Brown Electrodo de acero inoxidable 304 L Electrodo de acero inoxidable 420 MC