Investigation of Optimal Temperature for Thermal Catalytic Conversion of Marine Biomass for Recovery of Higher-Added-Value Energy Products

Abstract

The eutrophication process, caused by the uncollected seaweed and macroalgae, is a relevant and ongoing ecological issue. In case this biomass is collected from the seashores, it could be used as a potential feedstock for recovery of higher-added-value energy products. This paper aims to investigate the seaweed perspective of uses as a potential feedstock in the slow-pyrolysis process, using microthermal analysis combined with Fourier transform infrared spectrometry and experiments at the laboratory scale at different temperatures with two different types of zeolite catalysts. The primary investigation was performed using a micro-thermal analyser, and the results revealed that seaweed thermally decomposes in two stages, at 250 and 700 °C, while the catalyst slightly decreased the activation energy required for the process, lowering the temperatures of decomposition. Experiments on a laboratory scale showed that the most common compounds in the gaseous phase are CnHm, H2, CO, and CO2. Nevertheless, the most abundant liquid fraction derivatives are substituted phenolic compounds, pyridine, benzoic acid, naphthalene, d-glucopyranose, and d-allose. Furthermore, the catalyst decreased the amount of higher molecular mass compounds, converting them to toluene (71%), which makes this technology more attractive from the recovery of higher-added-value products point of view.