Avaliação do potencial energético da palha e talo da carnaúba

Abstract

Carnauba (Copernicia prunifera) is a plant species that exists in abundance in the northeast region, including in the state of Ceará, and is already used for extracting carnauba wax. The objective of this work was to evaluate the energy potential of the biomass from the stem and the carnauba straw as fuel for thermal energy generation. Characterization of carnauba stalks and straw in natura forms and briquettes was carried out. A comparison between the carnauba properties in the in natura and briquette forms was carried out in relation to the Ash, Volatile Content, Fixed Carbon Content, Moisture Content and Higher Heat Value (HHV) analyzes. The characterization of the residues was carried out using the guidelines contained in the Brazilian standards ABNT NBR 8112 and 8633. Also, ways of compaction of this material were studied by means of the transformation of this biomass into briquettes, which facilitates the handling and storage in large quantity. The methodology is to dry the in natura biomass and briquettes separately in a greenhouse and then burn them in a muffle oven, to obtain the results of immediate analysis. A calorimetric pump was used to determine PCS. The analysis revealed that carnauba straw and in natura stem had a moisture content (11.76% and 11.60%), respectively, whereas straw and stalk briquettes had a lower moisture content (9 , 34% and 9.96%). In relation to the volatile content, the values obtained were 70.89% and 81.12% for the straw and the in natura stem and 70.02%, 80.41% for the straw and threshing briquettes. As for the ash content, the results obtained were 9.13% and 2.80%, respectively for straw and fresh stalk and 8.99%, 2.75% for straw and threshing briquettes. For Fixed Carbon content 19.98%, 16.08% for straw and fresh stalk and 20.9%, 16.8% for briquettes, respectively. The obtained PCS results were 17.51 MJ / kg, 17.29 MJ / kg for straw and in natura stem and 17.76 MJ / kg, 17.44 MJ / kg for straw and thallium briquettes. The energy density of the briquettes increased from 2.98 to 12.78 kJ / cm³ and the briquette presented a mechanical resistance of 0.1 MPa; the stalk varied from 2.89 to 11.33 kJ / cm³ with a mechanical strength of 0.3 MPa; the blend (50% straw, 50% thallus) ranged from 2.79 to 11.98 kJ / cm³ with strength of 0.2 MPa. It is noticed from the results that the briquetting increases the energy density of the material and that the carnauba has a great application potential as a source of thermal energy.