Industrial energy efficiency has received increasing attention in many countries because of its importance in the pursuit of energy supply security, increased economic competitiveness and in the mitigation of greenhouse gases emissions. This paper aimed to evaluate the energy consumption development of the Brazilian pulp and paper industry through an energy decomposition analysis and an energy efficiency index approach over a 30 years period. An international comparison with other important paper-producing countries (i.e., Canada, United States of America, Finland and Sweden) was carried out. It was concluded that despite a significant increase in the energy efficiency levels, responsible for 5.6 PJ savings in electricity consumption and for 38.6 PJ savings in fuels consumption between 1979 and 2009, a saving potential of 7.8 PJ and 146.2 PJ related to the annual consumption of electricity and fuels, respectively, could be identified in the Brazilian pulp and paper industry. Among the countries evolved in the international comparison, both the Swedish and Finnish industries were the most efficient, followed by the Brazilian, American and Canadian, the latter being the only one where there was a reduction in the energy efficiency levels from 1979 to 2009.

A geração de resíduos alimentares cresce conforme aumenta a demanda por alimentos, sendo atrelada a toda a cadeia de produção alimentar. Isso evidencia que novas técnicas devem ser desenvolvidas para assegurar o manejo e o tratamento adequado desses resíduos. A digestão anaeróbia surge então como uma alternativa promissora para o tratamento desses resíduos, que simultaneamente promove a geração de energia limpa e renovável. Sendo assim, a presente pesquisa teve por objetivo elucidar as principais características sobre os parâmetros operacionais da digestão anaeróbia de resíduos alimentares. Os resultados apresentam os problemas encontrados na digestão anaeróbia bem como suas possíveis soluções, descrevendo as características operacionais envolvidas. Pode-se concluir que, dentre os parâmetros pertinentes à digestão anaeróbia de resíduos alimentares, o teor de nutrientes é o mais significativo, o qual pode ser corrigido com a adição de cosubstratos para que o processo ocorra de maneira mais estável.

Different mechanical configurations of diesel engines, when powered by biogas, can influence engine performance and efficiency. Consequently, this study aims to evaluate various generator engines to determine the optimal configuration for a distributed generation unit at a swine farm. In this study, we assess the biogas consumption, specific consumption, and efficiency of five biogas generator engines. Three engines (A, D, and E) were provided by Biogás Motores Estacionários, while the remaining two (B and C) were provided by Electro Hager models and MWM, respectively. The biogas used was produced in plug flow biodigesters (piston flow) by the treatment of swine waste. Engine A, provided by Biogás Motores Estacionários, exhibited specific consumption at a power of 30 kW (low load) similar to engines B and C. However, engines B and C displayed higher efficiencies at high loads compared to engines A, D, and E, attributed to their advanced fuel injection and control systems.

In this study, we compared cassava starch-based biodegradable polymers (PBMs) and glycerol (G) as additives used to increase biogas production from the co-digestion of swine wastewater (ARS). We chose to work with an inoculum comprising 40% (v/v) of the total volume of the reactor; this inoculum was obtained from a Canadian model digester for treating swine waste. In the anaerobic digestion process, batch reactors were used on a laboratory scale with a total volume of approximately 4 L and a working volume of 3.2 L. Three treatments were conducted to compare the efficiency of solid removal, the chemical oxygen demand (COD), and the production of biogas. The first treatment contained only swine waste; the second included the addition of glycerol at 1, 3, and 5% (w/v); and the third treatment included the addition of 1, 3, and 5% (w/v) of PBM residue in relation to the swine wastewater. From the results, it can be concluded that higher yields were obtained for the treatment with 3% PBM and 1% glycerol. Most treatments showed high removal rates of total solids and total volatile solids. Reductions lower than 70% were obtained only for treatments with PBM and glycerol at a ratio of 5%.

DIGESTÃO ANAERÓBIA DE RESÍDUOS ALIMENTARES UTILIZANDO ENSAIOS BMP

Through a review of the bibliographic base was identified the potential and difficulties of using biofuels based on babassu culture for use as aviation biofuel. Babassu palm is one of the most important crops for family farming in the north and northeast of Brazil due to its vast use potential. From babassu oil, by transesterification, good quality biodiesel can be obtained. However, it does not have the properties necessary to be used as aviation biofuel. Researches with biofuels from this culture and cultures with a similar organic profile were analyzed pointing out the feasibility of these biofuels as a mixture in aviation kerosene, nevertheless, these biofuels present several problems when used alone. Among the physical-chemical properties analyzed, the freezing point was a critical factor for not using these biofuels. This review points out the best results to improve the physicochemical properties of babassu biofuels to use as aviation fuel and present an important social factor to this palm uses.