Analysis of the performance of an extraction-condensation steam turbine on a cogeneration system of a Brazilian sugar-alcohol factory

In this work a detailed thermodynamic analysis for an extraction-condensation steam turbine capable to drive a 40 MVA electricity generator in a sugar-alcohol factory was carried out. The use of this turbine in the cogeneration system showed that its efficiency contributed to increase the power generation, although the condensation reduces the overall efficiency of the plant. Sensibility analyses were performed to evaluate the behavior of the overall energy efficiency of a plant with the extraction-condensation turbine in function of the boiler efficiency, the specific consumption of steam in the processes and the condensation rate in the turbine. It was observed that the plant efficiency is very sensible to the condensation rate variation and it increases when there is an increase in the demand of steam for processes.

Thermodynamic analysis of the cogeneration system expansion in a sugar-alcohol factory

In this work it was performed energetic and exergetic analyses of three thermal plants to assessment a cogeneration system in expansion of a sugar-alcohol factory. The initial configuration considered is constituted by a low pressure steam generator, single stage steam turbines for electricity generation and crusher, shredder and mills with mechanical driving. In the intermediary configuration, the low pressure steam generator was substituted by another which generates steam at higher pressure and higher temperature, the steam turbines for electricity generation were substituted by a multiple stages extraction-condensation turbine and the other steam turbines were maintained. The final configuration consists in the substitution of these last turbines by electrical motors. Thermodynamic analyses were performed to evaluate the equipment and the overall plants efficiencies to permit a comparison among the plants. Besides of this, some important parameters of the sugar-alcohol factories were calculated.

Analysis of efficiency and rationality in a sugar-alcohol mill using hyperboloid a-load and potency

Brazil is the world's largest producer of sugar cane and which in the state of São Paulo concentrate the greatest amount of sugar cane field of the country. The sugar-alcohol sector has the capacity to produce sufficient thermal and electrical energy to be used in their process of production and commercialize of surplus in electricity distribution network. Therefore it is necessary to evaluate the energy efficiency and rationality within the mill. Accordingly this research proposed analyze the sugar-alcohol mill's sectors globally and individually, located in the west center of the São Paulo state, using the valuation methodology employed by the Agência Nacional de Energia Elétrica (ANEEL) in the industries that do not have systems of cogeneration. In this analysis, the hyperboloids of load and potency were applied based on the indexes of potency factor and load factor that allow estimate the efficiency and rationality. © 2013 IEEE.

Análise termodinâmica, termoeconômica e econômica de uma usina sucroalcooleira com processo de extração por difusão

Pós-graduação em Engenharia Mecânica - FEIS

Análise termodinâmica e termoeconômica do aproveitamento do gás natural em sistemas de cogeração de energia de usinas de açúcar e álcool

Pós-graduação em Engenharia Mecânica - FEIS

Effects of KCl concentration on accumulation of acyclic sugar alcohols and trehalose in conidia of three entomopathogenic fungi

Beauveria bassiana, Metarhizium anisopliae and Paecilomyces farinosus were grown on Sabouraud Dextrose Agar (SDA) modified with KCl to give a range of water activity (a(w)) from 0.938 to 0.998. Growth of all three species was optimal at 0.983 a(w) and growth occurred over the a(w) range tested. Acyclic sugar alcohol (polyol) and trehalose content of conidia was determined by HPLC and found to vary with species and a(w). Conidia of B. bassiana and P. farinosus were found to contain totals of 1.5% and 2.3% polyols respectively at 0.998 a(w), and double these amounts at <0.950 a(w). Conidia of M. anisopliae contained from 5.7% to 6.8% polyols at each a(w) tested. In conidia of all three species the predominant polyol was mannitol. The lower molecular weight polyols, arabitol and erythritol, were found to accumulate at reduced a(w). Small amounts of glycerol were present in conidia of each species; <15% total polyols. Conidia of B. bassiana and M. anisopliae contained about 0.5% trehalose from 0.970 to 0.998 a(w), but only trace amounts below 0.950 a(w). Conidia of P. farinosus contained 2.1% trehalose at 0.998 a(w) and this decreased to <0.1% below 0.950 a(w). Potential to manipulate the endogenous reserves of conidia of these biological control agents to enhance viability and desiccation tolerance is discussed.

Multi-choice mixed integer goal programming optimization for real problems in a sugar and ethanol milling company

Goal Programming (GP) is an important analytical approach devised to solve many realworld problems. The first GP model is known as Weighted Goal Programming (WGP). However, Multi-Choice Aspirations Level (MCAL) problems cannot be solved by current GP techniques. In this paper, we propose a Multi-Choice Mixed Integer Goal Programming model (MCMI-GP) for the aggregate production planning of a Brazilian sugar and ethanol milling company. The MC-MIGP model was based on traditional selection and process methods for the design of lots, representing the production system of sugar, alcohol, molasses and derivatives. The research covers decisions on the agricultural and cutting stages, sugarcane loading and transportation by suppliers and, especially, energy cogeneration decisions; that is, the choice of production process, including storage stages and distribution. The MCMIGP allows decision-makers to set multiple aspiration levels for their problems in which the more/higher, the better and the less/lower, the better in the aspiration levels are addressed. An application of the proposed model for real problems in a Brazilian sugar and ethanol mill was conducted; producing interesting results that are herein reported and commented upon. Also, it was made a comparison between MCMI GP and WGP models using these real cases. © 2013 Elsevier Inc.

As transformações técnicas na agricultura canavieira: um estudo do setor canavieiro de Araras/SP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação energética e custo de produção da cana–de açúcar (Saccharum) do preparo de solo ao 5ºcorte

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Exploring the biological basis for Salmonella persistence in food manufacturing environments

The persistence of Salmonella spp. in low moisture foods is a challenge for the food industry as despite control strategies already in place, notable outbreaks still occur. The aim of this study was to characterise isolates of Salmonella, known to be persistent in the food manufacturing environment, by comparing their microbiological characteristics with a panel of matched clinical and veterinary isolates. The gross morphology of the challenge panel was phenotypically characterised in terms of cellular size, shape and motility. In all the parameters measured, the factory isolates were indistinguishable from the human, clinical and veterinary strains. Further detailed metabolic profiling was undertaken using the biolog Microbial ID system. Multivariate analysis of the metabolic microarray revealed differences in metabolism of the factory isolate of S.Montevideo, based on its upregulated ability to utilise glucose and the sugar alcohol groups. The remainder of the serotype-matched isolates were metabolically indistinguishable. Temperature and humidity are known to influence bacterial survival and through environmental monitoring experimental parameters were defined. The results revealed Salmonella survival on stainless steel was affected by environmental temperatures that may be experienced in a food processing environment; with higher survival rates (D25=35.4) at temperatures at 25°C and lower humidity levels of 15% RH, however a rapid decline in cell count (D10=3.4) with lower temperatures of 10°C and higher humidity of 70% RH. Several resident factories strains survived in higher numbers on stainless steel (D25=29.69) compared to serotype matched clinical and veterinary isolates (D25=22.98). Factory isolates of Salmonella did not show an enhanced growth rate in comparison to serotype matched solates grown in Luria broth, Nutrient broth and M9 minimal media indicating that as an independent factor, growth was unlikely to be a major factor driving Salmonella persistence. Using a live / dead stain coupled with fluorescence microscopy revealed that when no longer culturable, isolates of S.Schwarzengrund entered into a viable nonculturable state. The biofilm forming capacity of the panel was characterised and revealed that all were able to form biofilms. None of the factory isolates showed an enhanced capability to form biofilms in comparison to serotype-matched isolates. In disinfection studies, planktonic cells were more susceptible to disinfectants than cells in biofilm and all the disinfectants tested were successful in reducing bacterial load. Contact time was one of the most important factors for reducing bacterial populations in a biofilm. The genomes of eight strains were sequenced. At the nucleotide and amino acid level the food factory isolates were similar to those of isolates from other environments; no major genomic rearrangements were observed, supporting the conclusions of the phenotypic and metabolic analysis. In conclusion, having investigated a variety of morphological, biochemical and genomic factors, it is unlikely that the persistence of Salmonella in the food manufacturing environment is attributable to a single phenotypic, metabolic or genomic factor. Whilst a combination of microbiological factors may be involved it is also possible that strain persistence in the factory environment is a consequence of failure to apply established hygiene management principles.

A rapid HPLC protocol for detection of polyols and trehalose

A procedure was developed to extract polyols and trehalose (protectants against stress) from fungal conidia. Conidia were sonicated (120 s) and immersed in a boiling water bath (5.5 min) to optimize extraction of polyols and trehalose, respectively. A rapid method was developed to separate and detect low-molecular-weight polyols and trehalose using high-performance liquid chromatography (HPLC). An ion exchange column designed for standard carbohydrate analysis was used in preference to one designed for sugar alcohol separation. This resulted in rapid elution (less than 5 min), without sacrificing peak resolution. The use of a pulsed electrochemical detector (gold electrode) resulted in limits of reliable quantification as low as 1.6 μg ml-1 for polyols and 2.8 μg ml-1 for trehalose. This is very sensitive and rapid method by which these protectants can be analysed. It avoids polyol derivatization that characterizes analysis by gas chromatography and the long run times (up to 45 min) that typify HPLC analysis using sugar alcohol columns.

Controlo da fermentação do mosto e das condições ambientais de uma sala de lagares

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Mecânica

Contribution of fungi to primary biogenic aerosols in the atmosphere: wet and dry discharged spores, carbohydrates, and inorganic ions

Biogenic aerosols play important roles in atmospheric chemistry physics, the biosphere, climate, and public health. Here, we show that fungi which actively discharge their spores with liquids into the air, in particular actively wet spore discharging Ascomycota (AAM) and actively wet spore discharging Basidiomycota (ABM), are a major source of primary biogenic aerosol particles and components. We present the first estimates for the global average emission rates of fungal spores.

Measurement results and budget calculations based on investigations in Amazonia (Balbina, Brazil, July 2001) indicate that the spores of AAM and ABM may account for a large proportion of coarse particulate matter in tropical rainforest regions during the wet season (0.7–2.3 μg m⁻³). For the particle diameter range of 1–10 μm, the estimated proportions are ~25% during day-time, ~45% at night, and ~35% on average. For the sugar alcohol mannitol, the budget calculations indicate that it is suitable for use as a molecular tracer for actively wet discharged basidiospores (ABS). ABM emissions seem to account for most of the atmospheric abundance of mannitol (10–68 ng m⁻³), and can explain the observed diurnal cycle (higher abundance at night). ABM emissions of hexose carbohydrates might also account for a significant proportion of glucose and fructose in air particulate matter (7–49 ng m⁻³), but the literature-derived ratios are not consistent with the observed diurnal cycle (lower abundance at night). AAM emissions appear to account for a large proportion of potassium in air particulate matter over tropical rainforest regions during the wet season (17–43 ng m⁻³), and they can also explain the observed diurnal cycle (higher abundance at night). The results of our investigations and budget calculations for tropical rainforest aerosols are consistent with measurements performed at other locations.

Based on the average abundance of mannitol reported for extratropical continental boundary layer air (~25 ng m⁻³), we have also calculated a value of ~17 Tg yr⁻¹ as a first estimate for the global average emission rate of ABS over land surfaces, which is consistent with the typically observed concentrations of ABS (~10³–10⁴ m⁻³; ~0.1^–1 μg m⁻³). The global average atmospheric abundance and emission rate of total fungal spores, including wet and dry discharged species, are estimated to be higher by a factor of about three, i.e. 1 μg m⁻³ and ~50 Tg yr⁻¹. Comparisons with estimated rates of emission and formation of other major types of organic aerosol (~47 Tg yr⁻¹ of anthropogenic primary organic aerosol; 12–70 Tg yr⁻¹ of secondary organic aerosol) indicate that emissions from fungi should be taken into account as a significant global source of organic aerosol. The effects of fungal spores and related chemical components might be particularly important in tropical regions, where both physicochemical processes in the atmosphere and biological activity at the Earth's surface are particularly intense, and where the abundance of fungal spores and related chemical compounds are typically higher than in extratropical regions.

Contribution of fungi to primary biogenic aerosols in the atmosphere : active discharge of spores, carbohydrates, and inorganic ions by Asco- and Basidiomycota

Spores and related chemical compounds from actively spore-discharging Ascomycota (AAM) and actively spore-discharging Basidiomycota (ABM) are primary biogenic components of air particulate matter (characteristic size range 1–10 μm). Measurement results and budget calculations based on investigations in Amazonia (Balbina, Brazil, July 2001) indicate that the forcible discharge of fungal spores may account for a large proportion of coarse air particulate matter in tropical rainforest regions during the wet season. For the particle diameter range of 1–10 μm, the estimated proportions are ~25% during day-time, ~45% at night, and ~35% on average. For the sugar alcohol, mannitol, the budget calculations indicate that it is suitable for use as a molecular tracer for actively discharged basidiospores (ABS), and that the literature-derived emission ratio of about 5 pg per ABS may be taken as a representative average. ABM emissions may account for most of the atmospheric abundance of mannitol, and can explain the observed diurnal cycle (higher abundance at night). ABM emissions of hexose carbohydrates might also account for a significant proportion of glucose and fructose in air particulate matter, but the literature-derived ratios are not consistent with the observed diurnal cycle (lower abundance at night). AAM emissions appear to account for a large proportion of potassium in air particulate matter over tropical rainforest regions during the wet season, and they can also explain the observed diurnal cycle (higher abundance at night). The results of our investigations and budget calculations for tropical rainforest aerosols are consistent with measurements performed at other locations.

Based on the average abundance of mannitol in particulate matter, which is consistent with the above emission ratio and the observed abundance of ABS, we have also calculated a value of ~17 Tg yr−1 as a first estimate for the global average emission rate of ABS over land surfaces. Comparisons with estimated rates of emission and formation of other major types of organic aerosol (~47 Tg yr−1 of anthropogenic primary organic aerosol; 12–70 Tg yr−1 of secondary organic aerosol) indicate that emissions from actively spore-discharging fungi should be taken into account as a significant source of organic aerosol. Their effects might be particularly important in tropical regions, where both physicochemical processes in the atmosphere and biological activity at the Earth's surface are particularly intense, and where the abundance of fungal spores and related chemical compounds are typically higher than in extratropical regions.

O planejamento estratégico do capital humano como fator de desenvolvimento sustentável das organizações na agroenergia: estudo de caso

O objetivo desta tese é analisar, orientar e indicar algumas formas de mensuração de resultados das ações ou programas na área de Gestão de Pessoas ao longo dos anos, bem como de novas tendências no setor de agroenergia. O trabalho procura também propor práticas de planejamento estratégico e, indicadores para as organizações com foco no desenvolvimento e nas mudanças previstas nas organizações, no mercado de trabalho, nos modelos de gestão e de negócios do segmento de produção de cana-de-açúcar para os próximos anos. No estudo são analisados as transformações organizacionais, novos desafios competitivos do presente e do futuro, e a forma como a área de Recursos Humanos nas diversas organizações do setor, tem acompanhado tal processo, verificando o impacto dessas ações em um contexto de mudanças nos processos da cadeia agrícola (mecanização do plantio, colheita,.dentre outros), da cadeia industrial (biorefinarias, etanol de segunda geração, gaseificação...dentre outros), e no desenvolvimento organizacional e humano como parte integrante de um programa de sustentabilidade das organizações. São abordados metodologias, sistemas e ferramentas de planejamento estratégico, e mensuração propostas por certos autores que visam a demonstrar o impacto das estratégias e as ações na Gestão de Pessoas em direção ao cumprimento das metas e objetivos das organizações, em um cenário de forte crescimento interno e global do mercado de bioenergia. Nesse cenário, expõe-se e discute-se como as empresas do setor sucroalcooleiro utilizam, na prática, essas metodologias e os indicadores de performance da área frente às necessidades, e indicam-se as melhores práticas e ferramentas que visam a facilitar os processos decisórios, o uso de métricas de Recursos Humanos para previsão e acompanhamento do Capital Humano, e a otimização dos recursos e dos investimentos frente aos novos desafios do setor. Embora já se notem várias iniciativas visando a tornar a Gestão de Pessoas um fator estratégico para as organizações da agroenergia, a pesquisa identificou que a área de Recursos Humanos está evoluindo nessa direção e pode contribuir de forma efetiva para a melhor performance e sustentabilidade dos negócios. Palavras chaves: Cana-de Açúcar, Estratégia Organizacional, Capital Humano