Pirólise rápida de biomassa de eucalipto na presença de catalisador Al-MCM-41

<p></p><p>ABSTRACT Latin America has considerable potential in the production of biomass, mainly for the use of its waste, Brazil being one of the most important representatives in the generation of energy from these renewable sources. In this sense, the paper approaches eucalyptus biomass, in the form of residue, as a promising source of low cost for the production of energy and chemical products. The objective of this work is to perform the fast pyrolysis at 500 °C in the presence of mesoporous Al-MCM-41 catalyst to evaluate the performance of the phases (bio-oil, biogas and bio-coal), as well as to analyze the products generated in the liquid phase using a gas chromatograph with a coupled mass spectrometer. The catalysts and the biomass were characterized by scanning electron microscopy (SEM) and X-ray fluorescence (FRX). Elemental analysis, immediate analysis, calorific value and thermogravimetric analysis were performed for eucalyptus. Bio-oil, bio-gas and bio-carbon yields were obtained, compatible with the literature, besides proving that the presence of the catalyst influences directly in this distribution. The main compounds identified were acetic acid, 1-hydroxy-2-propanone, 1-1-diethoxyethane, furfural, confirming the importance of the process for obtaining chemical products.</p><p></p

Economic evaluation of post-weaning and finishing cattle supplemented on pasture

The objective of this study was to evaluate the economic viability, through different supplementation strategies, of the post-weaning and finishing stages of cattle supplemented on Brachiaria brizantha cv. Marandu pastures during the rainy and dry seasons. The experimental period was 447 d. The study comprised the post-weaning and finishing stages of 22 intact male crossbred (½ Holstein-Zebu) cattle with an average initial weight of 164.09 ± 12.13 kg and an average age of 7 mo. The animals were distributed in a randomized design with 11 replications per treatment. The following supplementation strategies were tested: strategy 1 (S1): Mineral mix in the 1st and 3rd periods and protein-energy supplementation at 0.2 % of the body weight (BW) in the 2nd period; and strategy 2 (S2): protein-energy supplementation at 0.4 % BW in the 1st and 3rd periods, and protein-energy supplementation at 0.6 % BW in the 2nd period. Strategy 1 resulted in a lower cost per arroba produced and lower cost per hectare, generating a greater net profit per hectare and consequently a higher internal rate of return. When herbage is available, mineral supplementation supplied during the rainy season, associated with low levels of protein-energy supplementation in the dry season (S1), is of greater economic attractiveness for the development of the project, as it leads to higher internal rates of return and net present values in the entire period