Catalytic solar hydropyrolysis of the Chlamydomonas reinhardtii microalgae

Abstract Hydrogen (H2) and bio-oil production from renewable sources are promising technologies in the energy sector. Particularly, the use of microalgae as a biomass source in the catalytic pyrolysis process in a hydrogen atmosphere is an encouraging approach in the production of high-quality bio-oil. This study combines two forms of harnessing renewable energy: (1) production of H2 through alkaline electrolysis with sunlight as the energy source, and (2) the production of bio-oil through catalytic hydropyrolysis of microalgae using solar energy as a thermal source in biomass degradation. The effects of catalyst (hydrotalcite precursor) percentage (C) and reaction time (t) on the product distribution and bio-oil content are analyzed. An average bio-oil yield of 45.77% is achieved using ex situ catalytic solar hydropyrolysis, which reaches up to 48.83% under optimal experimental conditions. The hydrogen atmosphere contributes to reducing oxygenated compounds and using a catalyst reduces nitrogenous compounds and raises the hydrocarbon level in the liquid fraction. The bio-oil composition is found to reach 37% of hydrocarbons.