Hidropirólise solar da microalga Chlamydomonas reinhardtii combinada com o precursor catalítico tipo Hidrotalcita

Abstract

Global energy demand is raising over the years owing to the hefty global economic growth. As consequence, carbon emissions related to energy generation also expands and a prompt revolution in power sector capable to lead towards a renewable energy future is still necessary. Hydrogen production as well as solar pyrolysis are promising process, which could contribute to the advancement of a transition route driving to a sustainable global development. The consortium of different renewable energies is important in the technological development for energy production and storage. Hydrogen and bio-oil production from renewable sources such as photovoltaic, wind and solar concentrators can contribute to the change in the world energy matrix, which is currently composed mostly by fossil fuels. The introduction of hydrogen in the thermochemical process has been shown important in the reduction of unwanted oxygenated compounds in the liquid product obtained in the pyrolysis process. The present work combines different forms of renewable energies. The production of H2 through alkaline electrolysis, using sunlight as energy source, converted into electrical energy through a photovoltaic panel. The production of bio-oil through the thermochemical process of hydropyrolysis, which uses solar energy as a thermal source in the biomass degradation to produce bio-oil, implementing a complete prototype to harvest solar energy in two different ways. The present study aims to ascertain the yield and quality of the liquid portion produced out of ex situ catalytic solar hydropyrolysis (CSH) of Chlamydomonas reinhardtii microalgae using a precursor of hydrotalcite type (HTC), [M(1 x)2+ Mx3+(OH)2]•[An−]x/n•mH2O, as catalyst and H2 gas produced by aqueous alkaline solar electrolysis. The effects of catalyst percentage and reaction time in a hydrogen atmosphere were evaluated in relation to product yields and features. Products yields were quantified using gravimetry technique and the liquid chemical composition were characterized by GCMS. The results revealed that the CSH combined with a catalytic hydrotalcite bed was able to produce an average yield of 45.77%, reaching 48.83% in the optimal experimental condition found using the Differential Evolution technique. The hydrogen atmosphere contributed to the reduction of oxygenated compounds and the catalyst was able to reduce nitrogenous compounds and raise the hydrocarbon level in the liquid fraction. The best result related to the bio-oil composition presented 37% of hydrocarbons, 24% of nitrogenous compounds and 39% of oxygen content, showing that the solar hydropyrolysis of Chlamydomonas reinhardtii microalgae combined with the hydrotalcite precursor is a promising alternative for biofuel production. The obtained bio-oil also presented different chemical compounds that can be used as solvents and precursors in the synthesis of fine chemicals or medicines.