THERMOCATALYTIC PYROLYSIS OF MICROALGAE BIOMASS USING PURE KIT-6 IMPREGNATED WITH COBALT AND MOLYBDENUM
Monoraphidium sp.; Scenedesmus sp; Acetylation; Thermocatalytic study; Kinetic study; KIT-6
A renewable and promising alternative to mitigate greenhouse gas emissions in the environment is the use of microalgae biomass. Therefore, the work aims to evaluate pre-treatment processes applied to microalgae, then synthesize KIT-6 and impregnate it with Cobalt and Molybdenum and, finally, evaluate the influence of these materials on the thermocatalytic pyrolysis of microalgae. The kinetic study was carried out using the Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods to evaluate the degradation of microalgal biomass. The thermodynamic parameters: Enthalpy (ΔH), Gibbs free energy (ΔG) and entropy (ΔS) were also calculated and, finally, the analysis of the bio-oils obtained from thermocatalytic pyrolysis was carried out. The pyrolysis of Monoraphidium sp. confirmed that the second acetylation promoted greater bio-oil formation, reaching a yield of 40%. Based on the correlation coefficient (R2) values, the KAS kinetic model best suits the degradation process, presenting Ea values of 147.30; 138.60; 145.80; 144.88 and 166.43 kJ.mol-1 for the following samples MA II, K6MA II, CoK6MA II, MoK6MA II and CoMoK6MA II, respectively. The average values of ΔH, ΔG and ΔS indicate that the thermal and thermocatalytic conversion of microalgae biomass is characterized as an endothermic, non-spontaneous and low reactivity process. Thermocatalytic pyrolysis showed a decrease in nitrogen compounds, indicating that KIT-6 pure and with the addition of metals improved the quality of the bio-oil.