Estudo sobre pirólise de microalgas

Abstract

This work investigated microalgae pyrolysis, with an approach in the influence of parameters in solar pyrolysis of microalga Spirulina platensis. First, it was conducted a description of the microalga, with chemical, immediate and element analysis, as well as thermogrametric and infrared analysis. Using a mirrored paraboloid, attached to a solar tracking system, a reactor was placed in the focal spot formed, where the pyrolysis reaction occured. The catalyst used was the hydrotalcite. The steam was removed from the reactor with the help from a vaccum pump and taken to a conditioning system, where part of the steam was conditioned. With the solid, liquid, gas masses and oxygen products from the bio-oil data, the influence of some parameters, biomass mass, reaction time and catalyst fraction, was evaluated. A factorial 2k was planned to evaluation of the parameters. The mass varied between 2.5 to 5g, the reaction time varied between 10 and 30 minutes and the catalyst fraction varied between 6.9 and 40.2%. The TGA analysis showed the behavior of Spirulina in different heating rates, showing protein, carbohydrate and lipid degradation regions. The infrared showed vibration from amide bondage, as well as carbohydrates, nitrile and amine. The studies, made in the software Statistica®, showed that the liquid yield was negatively influenced by the biomass amount used. The hypothesis for this behavior is that the biomass hinders the steam remotion favoring the repolymerization reactions. This hypothesis is reaffirmed by the positive influence of the biomass amount in solid yield. Gases and liquid yields were negatively influenced by the catalyst fraction, whereas solid yield was positively influenced. These data brings the hypothesis of catalyst hydrotalcite is favoring solid-product reactions. The oxygen-rich bio-oil was positively influenced by reaction time and was not significantly influenced by biomass amount.