Celso Oliveira
@fzea.usp.br
Biosystem Engeneering
UNIVERSIDADE DE SÃO PAULO
RESEARCH, TEACHING, or OTHER INTERESTS
Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Energy, Electrical and Electronic Engineering
Scopus Publications
Scopus Publications
Yuhan Arley Lenis-Rodas, Gilles Maag, Celso Eduardo Lins de Oliveira, Lesme Antonio Corredor, and Marco Enrique Sanjuan
Universidad de Antioquia
Gasification using an external heat source is considered as a high potential alternative to take high moisture content biomass into a fuel gas. This gas could reach energy densities close to 12 MJ/Nm3, which allows its use as a fuel in conventional thermal machines or as a precursor for higher fuel gases. Given this, in the present work allothermal gasification for a 50 %w.t. moisture content biomass was analyzed computationally aiming to yield a high hydrogen content syngas.
 Using a power supply of 8 kW, the dry tar-free gas yield was around 51.9 mol/kg of biomass with an average concentration of 45.7% CO, 44.8% H2, 4.8% CH4 and 4.6% CO2. A peak temperature of 1070 K and 33% for chemical efficiency were achieved. In spite of using homogeneous heating along the reactor wall, the process temperature decreases near the gas outlet. This is due to solid material depletion decreasing the process thermal inertia. During the final stages, H2 and CO concentration also record an increase due to the endothermic carbon gasification as well as water-gas shift and methanation reactions.
Yuhan A. Lenis, Gilles Maag, Celso Eduardo Lins de Oliveira, Lesme Corredor, and Marco Sanjuan
ASME International
Considering the potential of using concentrating solar power systems to supply the heat required for the allothermal gasification process, this study analyzes hydrogen production in such a system by assuming typical radiative heat flux profiles for a receiver of a central tower concentrated solar power (CSP) plant. A detailed model for allothermal gasification in a downdraft fixed bed tubular reactor is proposed. This considers solid and gas phases traveling in parallel flow along the reactor. Results for temperature and gas profile show a reasonable quantitative agreement with experimental works carried out under similar conditions. Aiming to maximize H2 yield, eight Gaussian flux distributions, similar to those typical of CSP systems, each with a total power of 8 kW (average heat flux 20 kW/m2), but with varying peak locations, were analyzed. The results show a maximum producer gas yield and a chemical efficiency of 134.1 kmol/h and 45.9% respectively, with a molar concentration of 47.2% CO, 46.9% H2, 3.3% CH4, and 2.6% CO2 for a distribution peak at z = 1.4 m, thus relatively close to the flue gas outlet. Hydrogen production and gas yield using this configuration were 4% and 2.9% higher than the achieved using the same power but homogeneously distributed. Solar to chemical efficiencies ranged from 38.9% to 45.9%, with a minimum when distribution peak was at the reactor center. These results are due to high temperatures during the latter stage of the process favoring char gasification reactions.
Marcia Saladini Vieira Salles, Suelen Corrêa da Silva, Fernando André Salles, Luiz Carlos Roma, Lenira El Faro, Priscilla Ayleen Bustos Mac Lean, Celso Eduardo Lins de Oliveira, and Luciane Silva Martello
Elsevier BV
P. Bezerra, Andreas Pfahl, Erwin Hölle, Phillip Liedke, Érico Tadao Teramoto, Johannes Hertel, Marcelo Lampkowski, and Celso Eduardo Lins de Oliveira
International Solar Energy Society
For Brazil it is important to realize a high local production share because of high import tax rates. The rim drive concept offers an alternative for expensive heliostat drive solutions with slew and linear drives from abroad. By (locally produced) rims the demands on the drives regarding strength and precision are reduced to a very low value and low cost drives can be used. Sandwich facets (which are usually foreseen for rim drive heliostats) are not available from Brazilian manufacturers and are replaced by a frame work steel structure with 4mm glass mirrors. The mirrors are bended only about one axis to avoid too high stress of the mirrors when low focal lengths (e.g. 30m) have to be realized. For an 8.1m² heliostat the mirror panel was divided into six stripes of 2.5m x 0.54m. The stripes have to be canted to reach a sufficiently small focal spot. An accordant heliostat was designed and built. High stiffness was reached and sufficient durability of the mirror facets against wind loads. For 8m² heliostats the framework design should be simplified but for 16m² heliostats (or bigger) it seems to be appropriate.
G. Maag, Kimberly Tolentino de Oliveira, and Celso Eduardo Lins de Oliveira
International Solar Energy Society
José A. Rabi, Robson L. Silva, and Celso E. L. Oliveira
Springer Science and Business Media LLC
Exergetic analysis can provide useful information as it enables the identification of irreversible phenomena bringing about entropy generation and, therefore, exergy losses (also referred to as irreversibilities). As far as human thermal comfort is concerned, irreversibilities can be evaluated based on parameters related to both the occupant and his surroundings. As an attempt to suggest more insights for the exergetic analysis of thermal comfort, this paper calculates irreversibility rates for a sitting person wearing fairly light clothes and subjected to combinations of ambient air and mean radiant temperatures. The thermodynamic model framework relies on the so-called conceptual energy balance equation together with empirical correlations for invoked thermoregulatory heat transfer rates adapted for a clothed body. Results suggested that a minimum irreversibility rate may exist for particular combinations of the aforesaid surrounding temperatures. By separately considering the contribution of each thermoregulatory mechanism, the total irreversibility rate rendered itself more responsive to either convective or radiative clothing-influenced heat transfers, with exergy losses becoming lower if the body is able to transfer more heat (to the ambient) via convection.
Marco Antonio Trindade, Marta Mitsui Kushida, Nilda D. Montes Villanueva, David Uenaka dos Santos Pereira, and Celso Eduardo Lins de Oliveira
Elsevier BV
The aim of this study was to investigate the effects of the use of chlorine or ozone as sanitizing agents in the water of chicken immersion chilling, using the residual levels usually applied in Brazil (1.5 ppm), comparing the effects of these treatments on the microbiological, physicochemical, and sensory characteristics of carcasses. Chicken carcasses were chilled in water (4°C) with similar residual levels of ozone and chlorine until reaching temperatures below 7°C (around 45 min). The stability of carcasses was assessed during 15 days of storage at 2 ± 1°C. Microbiological, surface color (L*, a*, b* parameters), pH value, lipid oxidation (thiobarbituric acid reactive substances index), and sensory evaluation (on a 9-point hedonic scale for odor and appearance) analyses were carried out. The presence of Salmonella was not detected, coagulase-positive staphylococci counts were below 10(2) CFU/ml of rinse fluid, and Escherichia coli and total coliform counts were below 10(5) CFU/ml of rinse fluid until the end of the storage period for both treatments. Psychrotrophic microorganism counts did not differ (P > 0.05) between chlorine and ozone treatments, and both values were near 10(9) CFU/ml of rinse fluid after 15 days at 4 ± 1°C. pH values did not differ between treatments (P > 0.05) or during the storage period (P > 0.05). In addition, neither chlorine nor ozone treatment showed differences (P > 0.05) in the lipid oxidation of carcasses; however, the thiobarbituric acid reactive substances index of both treatments increased (P ≤ 0.05) during the storage period, reaching values of approximately 0.68 mg of malonaldehyde per kg. Samples from both treatments did not differ (P > 0.05) in their acceptance scores for odor and overall appearance, but in the evaluation of color, ozone showed an acceptance score significantly higher (P ≤ 0.05) than that for the chlorine treatment. In general, under the conditions tested, ozone showed results similar to the results for chlorine in the disinfection of chicken carcasses in the immersion chilling, which may indicate its use as a substitute for chlorine in poultry slaughterhouses.
Celso da Costa Carrer, Guilherme Ary Plonski, Célia Regina Orlandelli Carrer, and Celso Eduardo Lins de Oliveira
FapUNIFESP (SciELO)
This research wants to lay emphasis on topics that historicize and rescue concepts, in addition, shows the relation between innovation and socioeconomic development resulted; reviews the legal framework to stimulate new innovation into Brazilian society; considers the definition and the entrepreneur university's new paradigm; and finally, this research highlights the importance of teaching entrepreneur at universities, with straight society benefits. The results suggests that innovation is directly enrolled with a successful development of certain society, as well, is actually the biggest business competitive differential into corporative universe. In one way of getting results of social advancement to inform entrepreneur research practice, it appears that entrepreneurs concepts, necessarily, must be incorporated into the array of Science/Technology/Innovation for the effective development of supported formula. This article develops a thought about actual scientific researches paradigm, the way that is built on today, and if it's sufficient to effectively get the results that society expects from main bodies to create human resource and researches, especially those with innovation aspects, at Brazilian economic improvement.
Celso E. L. de Oliveira, José L. Garcia, Saturnino De La Plaza, and Carolina Chaya
FapUNIFESP (SciELO)
O Coeficiente Global de Perdas de Calor (U) permite o equacionamento das necessidades térmicas de uma casa de vegetação climatizada. No presente trabalho, determinou-se esse coeficiente cujo referencial foi uma casa de vegetação localizada em Madri (Espanha), em que foram utilizadas medidas noturnas de temperatura do ar no interior, no exterior, bem como o consumo de energia para aquecimento. As comparações entre as técnicas de aquecimento utilizadas foram: solo radiante e aerotermos combinados com duas técnicas que visavam a promover melhor aproveitamento térmico, ou seja, a utilização de cobertura plástica formando dupla capa ou a utilização de túnel plástico. Os menores coeficientes foram conseguidos para a utilização de solo radiante com túnel e aerotermos com dupla capa com 7,19 W m-2 ºC-1 e 9,11 W m-2 ºC-1, respectivamente; o maior valor dentre os coeficientes nas condições estudadas foi 15,13 W m-2 ºC-1 ao considerar o uso de aerotermos sem utilização de plásticos. Conclui-se, portanto, que os resultados comprovam o melhor rendimento térmico para as técnicas ensaiadas.