Cinética da pirólise da palha e do talo de carnaúba usando análise termogravimétrica e o método isoconversional de Friedman

Abstract

The fossil fuels continuous use coupled with the growing concern about he growing concern about global warming and environmental pollution motivates the search for renewable energy sources and alternative technologies for their generation. In this scenario, the biomass residues use becomes one of the alternatives of renewable raw materials for energy generation and biofuel production through conversion processes. The thermochemical biomass conversion, such as pyrolysis, constitutes a promising and attractive strategy for the waste use, being considered an environmentally correct disposal route with potential economic benefits and the generation of high value-added products. An alternative for the residual biomass use is by obtaining energy from the pyrolysis process, which has the potential to transform biomass into solids, liquids and gases; understanding this process involves studying the residual biomass kinetics degradation. Based on this bias, it was necessary to study the by-products (straw and stalk) of the carnauba wax production, an abundant palm tree in the northeast region of Brazil, which is widely used for various purposes - straw is used in handicrafts, the roots are used in medicinal medicines, the trunk is used in civil construction, the palm heart can serve as food for animals, the dry straw (bagana) serves as an excellent quality organic fertilizer and the wax has multiple utilities in various branches of industry - and also known as Copernicia Prunifera Prunifera. Thus, the work main objective is to investigate the pyrolysis kinetics o f carnauba straw and stalk after wax extraction, using thermogravimetric analysis (TGA) under non isothermal conditions and lignocellulosic characterization The experiments were carried out in an inert atmosphere (nitrogen) with a flow rate of 50 𝑚𝐿 𝑚𝑖𝑛 at different heating rates: 5 10 15 𝑒 20 𝐶 𝑚𝑖𝑛. From the lignocellulosic characterization for carnauba straw, alphacellulose, holocellulose, hemicellulose, lignin, extractives, moisture and ash contents were observed, respectively, of 26.32%, 52%, 25.67%, 34.43%, 4.18%, 8.19% and 11.32%, and for the carnauba stalk, levels, respectively, of 20.86%, 46.35%, 25.5%, 30.37%, 9.44%, 9.87% and 4.53%. From the TG/DTG data of carnauba straw and stalk, it was possible to calculate the activation energy 𝐸𝑎 for each α conversion, using Friedman's differential isoconversional method, in which the average value of 𝐸𝑎 found was 225 28 𝑘𝐽 𝑚𝑜𝑙, with standard deviation of 26.83 for straw and mean value of 𝐸𝑎 of 218 13 𝑘𝐽 𝑚𝑜𝑙 with standard deviation of 28.06 for stalk. The results were compared with other biomasses, validating the results found in this study.