RESUMO
This study is the first report that focuses on investigating the effects of torrefaction on the bioenergy-related properties, combustion behavior, and potential emissions of banana leaf waste (BLW). Experiments were first conducted in a bench-scale fixed-bed reactor operating at light (220 °C), mild (250 °C), and severe (280 °C) torrefaction conditions to torrefy the raw BLW. Torrefaction pretreatments reduced the weight of the raw BLW by about 60%, but the resulting solid biofuel can preserve up to 77% of the energy content of the raw biomass. It was found that torrefied BLW contains more concentrated fixed carbon than the raw BLW, volatile matter content of up to 59.8 wt.%, and a higher HHV of up to 20.7 MJ kg-1 with higher concentrations of carbon, nitrogen, and ash. Bulk density increased 13.0% over the raw BLW, and the torrefied BLW became a solid biofuel with 51.5% greater energy density under the severe torrefaction condition. The upgrading of BLW by torrefaction enhanced its combustion performance in terms of comprehensive combustion, ignition, burnout, and flammability indices. Compared with commercial hard coal, BLW torrefied at the mild condition (250 °C) had lower potential emissions per unit of energy, 25.3% less CO2 emission, 3.1% less CO emission, 96.4% less SO2 emission, and 18.4% less dust emission, except for NOX emission. This study conclusively indicates that BLW after torrefaction has enhanced bioenergy-related properties, improved combustion performance, and reduced emissions potential, proving to be a promising method for its valorization.
Assuntos
Biocombustíveis , Musa , Biomassa , Carbono , Folhas de Planta , TemperaturaRESUMO
Abstract Data Centers are growing steadily worldwide, and they are expected to continue growing up to 53% in 2020. Energy efficiency, in high power consumption, is a key venue. There are methodologies to measure this efficiency, one example is using the PUE (Power Usage Effectiveness) index. In this paper is proposed a new index for measuring efficiency at the design stage, the EUED (Energy Usage Effectiveness Design). This index allows to evaluate systems using "free cooling" and adiabatic system. A comparison is performed considering the equipment in the worst situation. The thermodynamics parameter enthalpy is used to calculate the results. This new methodology allows to determine differences between the cities of São Paulo and Curitiba (1.21%) and between Rio de Janeiro and Curitiba (10.61%). The values for the EUED index were 1.245 kW/kW for Curitiba, 1.260 kW/kW for São Paulo and 1.377 kW/kW for Rio de Janeiro, respectively, reaching a difference of 16.86% for Curitiba, 16.19% for São Paulo and 10.31% for Rio de Janeiro in relation to PUE COA (Power Usage Effectiveness Constant Outdoor Air). The advantage of the EUED is that it works with the 8,760 hours in the design phase, using psychometric elements to determine when to use free cooling and evaporative system, and more importantly varying the COP according to environmental characteristics.
Assuntos
Eficiência , Consumo de Energia , Temperatura Alta , TermodinâmicaRESUMO
This work aimed to investigate the antioxidant capacity of the guava agroindustrial waste as a functional additive in broiler feed to improve the performance and meat quality of boilers. The experiment was conducted in a completely randomized design, consisting of four treatments and six replicates with 12 birds. Treatments included different levels of guava byproduct in the feed: 0, 0.5, 1.0, and 1.5%. We evaluated the performance of broilers at 7 and 21 days old. At 21 days old, two birds from each experimental unit were euthanized for intestine histologic evaluation (duodenum, jejunum, and ileum) and breast and deboned thigh samples were collected for analyzes of pH, colorimetry (L*, a*, and b*), and thiobarbituric reactive substances (TBARS). The use of guava byproduct in the diet at 7 days old did not affect feed intake and feed conversion of the birds. However, the body weight and weight gain increased linearly with the inclusion of the byproduct. At 21 days old, the guava byproduct did not depress the performance of birds. There was no effect of treatments on villus height, crypt depth, and villus:crypt ratio of the duodenum and jejunum of the birds. The inclusion of guava byproduct resulted in lower crypt depth and linear increase in villus:crypt ratio of the ileum. There was no significant difference in pH and colorimetry of the breast and thigh. With increasing inclusion of byproduct, TBARS value was reduced to 0.72%, indicating greater lipid stability in thigh meat in this inclusion amount. Guava byproduct can be used as an alternative antioxidant additive in broiler feed because it does not depress the productive performance and improves thigh meat quality of boilers.(AU)