Pirólise solar catalítica de microalgas

Abstract

In past decades, new investments in renewable energy sources have been highlighted.According to the International Energy Agency (IEA) these investments are led by solar, wind and biomass sources. The process of solar pyrolysis is a technology that combine the use of biomass and solar energy as a potential solution to harness the energy of the sun by converting biomass energy into transportable and storable fuel and also chemicals of interest.In the context of the generation of renewable fuels, algae-derived fuel has been presented as a promising alternative with potential to meet global fuel demand. This is because this biomass presents a form of simple cultivation has no crop and can be generated continuously even on uncultivated land. However, the bio-oil generated from both lignocellulosic materials (traditionally used) and the bio-oil generated in the pyrolysis of microalgae present undesirable components in their composition, so investigative processes to improve the quality of this bio-oil have been developed in order to use oil as a source of fuel and chemicals of interest.The aim of this thesis was to characterize and evaluate the potential of two microalgae biomasses to Chlamydomonas reinhardtii and Spirulina Platensis in the generation of bio-oil via solar pyrolysis. n addition to evaluating the use of the hydrotalcite type catalyst in the improvement of the quality of the bio-oil generated. For this, several characterization techniques were used and solar tests were performed according to the Central Composite Design technique. The characterization analyzes revealed that both biomasses have potential for fuel generation. According to the FRX analysis the Spirulina biomass, according to the minerals present and respective proportions, was more adequate to the gasification process. In the study of the analytical pyrolysis of Chlamydomonas reinhardtii, in the absence of catalyst, it was indicated that the increase in temperature increased the amount of hydrocarbons and decreased that of oxygenated compounds. However, the bio-oil produced from catalytic pyrolysis of this microalga showed a decrease in the nitrogenous compounds, detrimental to the quality of the bio-oil. In the solar tests of Chlamydomonas reinhardtii using the technique of Central Composite Design and response surface, the analysis of the main effects showed that the most significant in the net yield was the interaction between the time and the mass load of microalgae used in the reactor. As for the quality of the bio-oil, the oxides derived from hydrotalcite showed a good performance, since they decreased the nitrogen compounds and increased the relative percentage of hydrocarbons, in the same sense obtained in the previous tests of analytical pyrolysis. The solar tests with the Spirulina platensis microalgae revealed some similarities with the solar pyrolysis of Chlamidomonas reinhardtii, both having the same optimum points of microalgae mass loading and reaction time for the generation of liquid products. However, the catalyst worked in different ways in the microalgae used, probably due to the distinction of chemical composition between them. The use of a catalyst percentage of 23.35% was more adequate for optimization of the liquid in the case of Chlamydomonas reinhardtii. In turn, the use of a percentage of the catalyst of 43.33% was more favorable for the conversion of the biomass to liquid in the case of Spirulina platensis. From the development of this work it can be concluded that solar energy has the potential to be used as an energy source for thermal processes at high temperatures