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Many correlations in the literature have been proposed to predict the external heat transfer coefficient, but most of them are suggested for batch operations. This paper aims to experimentally investigate a steady state condition (usually found in industrial processes) of mixed vessels equipped with a four 45° pitched-blade turbine and vertical tubular baffles to determine the external heat transfer coefficient. An empirical correlation based on the work of Sieder–Tate [Ind. Eng. Chem. 1936, 1429–1435] for a steady state condition using standard configuration of a mixing system is being proposed. A sucrose solution of 20% and 32% concentrations (w/w) and a mixing apparatus with a 50 L cylindrical flat bottom vessel are employed. Water was used as heating fluid running inside the vertical tubular baffles with an inlet temperature range from 25 to 45 °C and an impeller speed from 30 to 330 rpm. A new fit correlation was proposed based on the Sieder–Tate modeling, yielding good agreement with experimental data in steady states with deviations of less than 15% between observed and predicted external heat coefficients.

Inulin is a storage polysaccharide present in more than 30,000 vegetable products, including chicory roots, that are considered suitable for industrial application. The objective of this work was to evaluate the influence of temperature and the soluble solids concentration on the rheological behavior of a concentrated inulin solution obtained from a centrifugation process from chicory roots, after freezing at −24C. For all the evaluated soluble solids concentrations, inulin solutions showed a rheological behavior of a highly pseudoplastic fluid, with high resistance to flow at low strain rates followed by a breakdown of the structure when the shear rate increased. The effect of temperature on the apparent viscosity of inulin solutions can be represented by the Arrhenius equation. The rheological behavior of inulin solutions can be represented by the Herschel–Bulkley, Casson, Cross and Power Law equations, where the consistency index increases as temperature rises and the soluble solids concentration as well. PRACTICAL APPLICATIONS The main objective of this work was to analyze the rheological behavior of a concentrated inulin solution obtained from chicory roots, to check the possibility of its application to obtain powder inulin. The concentrated inulin solution was obtained by diffusion in hot water, followed by concentration by evaporation and phase separation conducted by lowering the temperature (−24C) and centrifugation at a velocity of 10,000 rpm for a time interval of 15 min. However, this solution is still going to be processed. Therefore, it is important to know its rheological behavior. The influence of temperature and the soluble solids concentration on the rheological behavior of the concentrated inulin solution was also studied.

É possível estabelecer uma relação entre o teor de água livre na semente e sua conservação, expresso pela atividade de água, através da relação entre a pressão de vapor de água em equilíbrio na semente e a pressão de vapor de água pura, à mesma temperatura. Uma isoterma é uma curva que descreve a relação de equilíbrio de uma quantidade de água sorvida por componentes da semente e a pressão de vapor ou umidade relativa, a uma temperatura específica. O objetivo deste trabalho foi estudar as isotermas de sorção para sementes de feijoeiro dos cultivares Tibatã e Una. Os graus de umidade das sementes foram ajustados, antes do armazenamento, em dessecadores com sílica gel ou através de reidratação sobre água. Para o controle da quantidade de água removida ou absorvida, as subamostras foram pesadas periodicamente, sendo o processo encerrado ao ser atingido o peso correspondente ao grau de umidade final desejado para cada tratamento. Foram realizadas determinações de umidade e de atividade de água e utilizados diferentes modelos de equações empíricas que correlacionam dados experimentais das isotermas de sorção em materiais biológicos. O melhor ajuste das isotermas de sorção foi alcançado pelos modelos de Oswin e Peleg para sementes de feijoeiro, cultivares Tibatã e Una, respectivamente.

There are several correlations used to predict the external heat transfer coefficient in tanks equipped with vertical tube baffles in batch operations, but little information concerning the external heat transfer coefficient in steady state operations. The objective of the present article is to experimentally determine a correlation of the external heat transfer coefficient based on the model proposed by Sieder and Tate (Ind. Eng. Chem. 1936, 1429–1435) in a steady flow rate in a vessel equipped with a radial impeller, turbine type, with six flat blades. The study was carried out in a 50 dm3 working capacity acrylic vessel, fitted with vertical tube baffles made of copper, in which water and sucrose solutions at mass concentrations of 20% and 50% were heated. Heating temperatures varied from 28 to 45 °C, whereas the rotations varied from 90 to 330 rpm. From the Nusselt, Reynolds, and Prandtl similarity parameters, a correlation was obtained which yielded excellent results of the observed data–a maximum deviation of 21% between the observed and predicted data for the external heat transfer coefficient. In addition, one could also observe that the radial impeller raises the heat transfer to as much as 70% compared to the axial impeller for the same study conditions.

Brazil is the world's largest producer and consumer of passion fruit, being a tropical fruit that produces a lot of waste in its process. As this residue is more than 60% of the mass of the fruit, there is a problem directed to the discard of the same. One way to add economic and financial value to the passion fruit industry would be to use the waste as a source of fuel in a process of converting biomass to energy. The objective of this work was to characterize samples of passion fruit residues by analyzing the moisture content and the experimental calorific value, aiming at its energy utilization, in order to obtain initial information to help define the best conversion path of this biomass: thermochemical or biochemical. After analysis, it was concluded that the most appropriate biomass utilization route would be anaerobic biodigestion due to the high moisture content presented in the samples (greater than 80%). However, the same ones, if in dry basis, also have high calorific value, compared, for example, with sugarcane bagasse. With the results, it was demonstrated that the biomass of the passion fruit pulp presents itself as a potential alternative for the energy utilization.

A Política Nacional de Resíduos Sólidos (PNRS) do Brasil objetiva promover a gestão integrada e o gerenciamento dos resíduos sólidos, de modo a assegurar um destino final ambientalmente adequado. A disposição dos resíduos sólidos domiciliares (RSD) é um desafio na maior parte dos municípios brasileiros, muitas vezes efetuada sem tratamento prévio, com inúmeros impactos ambientais negativos. Nesse contexto, o objetivo deste estudo foi analisar o potencial energético dos RSD do Brasil, a partir do atual cenário do gerenciamento desses resíduos.  O estudo foi feito a partir da estimativa do potencial energético das principais frações combustíveis que compõem os RSD brasileiros, combinando-se informações obtidas da literatura. A fração mais significativa é de matéria orgânica, seguida de recicláveis e por fim rejeitos, com cerca de 51%, 35%, e 14% respectivamente. Com intuito de mostrar os benefícios econômicos e ambientais que esse tipo de resíduo apresenta como recurso, o tratamento é uma alternativa para a demanda de energia que a cada dia aumenta, como solução já que os recursos naturais tendem a esgotar.