RCAAP Repository

Among the various renewable feedstocks available for ethanol fuel production, special emphasis has been given to sweet sorghum because the extracted juice of its stalk is composed of sucrose, glucose, fructose and can therefore be easily fermented to produce ethanol. In this paper we evaluate the behavior of the concentrations of sugars (sucrose, glucose, and fructose), nutrients (N, Ca, Mg, P) and starch in the juice from four sweet sorghum cultivars developed by Embrapa Maize and Sorghum (BRS 506, BRS 507, BRS 509, BRS 511) during time of maturation. The industrial use period was also determining the yield of cane and ethanol production using sweet sorghum juice in different planting dates. The cultivars showed different concentrations of sugars, industrial use period, and productivity between them as well as between the ages of plantings, showing influence of climatic conditions and the characteristics of each cultivar. All cultivars showed similar behavior with regard to nutrient content which were characterized by decreased concentration of nutrients throughout the analysis and increase in starch period. After fermenting both cultivars for 8 hours, it was found that cultivar BR 508 showed the best performance in terms of productivity (9.0 g/Lh) and yield (YP/ART = 90.5 %). Also, the feasibility of freezing the juice of sweet sorghum was verified and it was observed that after 30 days the levels of total sugars were reduced in their concentrations. Characterizations of sugar content were made in different parts of the stalk for the four cultivars and found that higher concentrations of total sugars are at the base of the stalk. Fermentations of the sorghum cultivars was carried out in order to evaluate the effectiveness of nutrient addition and stirring during fermentation process, which found that these two parameters did not add gains during fermentation. The fermented broths with different concentrations of sorghum sugar , in comparison with the juice of sugar, in order to evaluate the effect of different concentrations of total sugar (160, 180, 220, 260, and 300 g/L) yield the fermentation. It was found that with increasing sugar concentration, it did not increase the production of ethanol to concentrations of 160, 180, 220, and 260 g/L and the concentration was reduced to 300 g/L, showing inhibition on ethanol production when using sorghum broth with increased initial concentration of sugar and it has been found that yield and productivity in 8 hours of fermentation broth for the sorghum was from 0.8 to 4.8% and from 2 to 3.7% higher fermentations sugarcane juice under the same conditions. Reviews the use of enzyme a-amylase and amyloglucosidase the enzymatic hydrolysis of the juice in the juice of this sweet sorghum starch were made. It was noticed that the joint action of the addition of the two enzymes in the broth provided greater hydrolysis of starch present in the juice of sweet sorghum, an increase of 1.67 gallons of ethanol per ton of processed sweet sorghum .

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Iinteractions between flavor molecules and other compounds are often investigated in binary and ternary systems (for example, water, aroma compounds, carbohydrates) to characterize specific release mechanisms. The influence of different types of sugar should be noted that in situations where they are part of the solution of interest. However, the release of aromas complex food matrices is difficult to predict and the knowledge of data solubility are useful in the development of industrial processes. Solubilities of butyl acetate and ethyl acetate from pure water and aqueous solutions of low viscosity was investigated. Aqueous solutions were prepared with sucrose, glucose and fructose in concentration range 10-30 g L-1. The static method was used and the concentrations of aroma compounds in thermodynamic equilibrium was monitored by gas chromatography with a flame ionization detector (CG -FID). The experiments were performed in the temperature range of 5-25 ° C, using jacketed Pyrex glass vessels connected in series, called cells, interconnected by a latex hose and connected to a thermostatic bath to control the temperature during the experimental trials. The samples were shaked for 2 h, then they were kept at rest for 24 h and only after these step, triplicate sampling of 1μL injection were carried out in the gas chromatograph. Solubilities of butyl acetate and the ethyl acetate mixtures and the pure water increased with decreasing temperature. The flavour components are retained more extensively in the presence of glucose solutions in comparison with that of pure water. In some situations the size of the sugar molecule showed negatively influence on the solubility of the esters, suchs as sucrose, that due to its higher molecular mass competed with the ester molecule by water. All aqueous solutions had a similar behavior as the sugar concentration was increased when, although it was expected that the molecular weight of sugar could have an influence on the equilibrium concentration. The acetate-water-sugar systems thermodynamic equilibrium reached time to time equal to 22 h, both as the butyl acetate to ethyl acetate. The gas chromatography was found to be valid to determine the solubility of the esters in pure water and in aqueous solutions. Besides the experimental data, it was also possible to correlate the experimental data by estimating parameters of four equations. Results solubility of ethyl acetate in water is in agreement with the literature. The experimental solubility and solubility available in the literature of butyl acetate in pure water at 25 °C are equal to 0.5917 g 100g-1 and 0.5928 g 100g-1, respectively. The value experimental solubility of ethyl acetate in pure water was equal to 7.1504 g 100g-1 and the literature value is 7.270 g 100g-1. The correlation of the experimental data set in software were satisfactory.

In this thesis are presented experimental measurements of pressure drop and profiles of velocity and pressure gradient simulated via CFD of non-Newtonian fluids in annular ducts concentric/eccentric, with/without rotation of the inner tube, for cases with/without partial obstruction of the annular region. Annular fluid flow is a relevant subject for many industrial applications, especially for the oil and gas industry. It is very important to know the fluid dynamics of the drilling fluid, to assure a proper cleaning of the well and to reduce the effective costs of the operation.In directional drilling often the annulus is eccentric as a result of the column weight, and due to drill bit fluctuations, the eccentricity may vary along the length of the well. Furthermore, by the gravity effect there will be a strong tendency for the solids to accumulate in the bottom of the well, forming a bed of settled cuttings that partially obstructs the flow, which can hinders and even interrupt the drilling operation. For this reason it is important to study the effect of the overlap of these two factors (eccentricity and obstruction) in the flow, which has not been addressed in the literature. Thus, a partnership formed between PETROBRAS and FEQUI/UFU research group allowed the development of this work. A experimental design was used to the acquisition of data regarding hydrodynamic losses in horizontal sections with partial obstruction of 6 mm considering the eccentricity (0, 0.23 and 0.46), flow rate (3, 6 and 9 m3/h), Xanthan Gum concentration (0.1, 0.3 and 0.5%) and rotation of the inner cylinder (0, 200 and 400 rpm). Numerical simulations conducted by using the software FLUENT® 14.0 for periodic sections with different eccentricities (0, 0.23 and 0.46) and obstruction heights (0, 6 and 12 mm) allowed evaluating the influence of operating variables (flow rate of 3 and 9 m3/h and rotations of 0 and 400 rpm) and rheology of the fluid (0.1 and 0.5%) on the flow (axial and tangential velocities profiles and pressure drop data). The injection of particles allowed visualization and dimensioning of the helical path of the same in the annular, which were compared with streamlines simulated by FLUENT®. Comparisons between numerical calculations and literature data indicated, in general, a very good agreement. The results reported on helical flow in annular partially obstructed are a novelty in literature and allow a better understanding of the complex phenomena that may occur in drilling of horizontal and inclined wells.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Due to social and environmental issues, considerable attention has been given to the production of biodiesel in substitution or addition of petroleum diesel. Biodiesel a mixture of fatty acids methyl esters is a renewable fuel obtained from a transesterification of vegetable oils and animal fats, in which alkaline hydroxides are used as catalyst. This process presents two main disadvantages: the catalyst cannot be reutilized or regenerated and there is a high quantity of residual water being produced during the separation fases. In this way, the production of biodiesel by means of heterogeneous catalytic transesterification becomes an interesting alternative in order to minimize the problems associated with homogeneous catalytic. In this respect, this study evaluates the production process of biodiesel by means of soybean oil methanolysis utilizing free and supported solid alkaline catalysts in a polymeric matrix. Initially, three distinct mixed oxides (Hidrotalcita de Mg/Al; CaO-CeO2 e CaZrO3) have been synthesized. These oxides were also supported in polysulphone (PS) and polyvinyl alcohol (PVA). The catalysts samples were physically and chemically characterized by different technics. These samples were then evaluated for their catalytic performance in the transesterification reaction, for pre-established conditions. It has been found that the CaZrO3 free and supported in PVA showed the best performance, attaining conversions greater than 90% in all conditions investigated. Thus, these two catalysts were selected for further experiments. It has been analyzed the influence of the operational conditions (methanol/oil molar ratio, temperature, amount of catalyst and time reaction) in the conversion of soybean oil into fatty acids methyl esters (% FAME). These conditions were optimized applying artificial neural network methodology in order to obtain the highest %FAME. Furthermore, it has been studied the behavior of different configurations of reactors (magnetic agitation, ultrasonic agitation with and without recirculation), the biodiesel synthesis in a spiral catalytic membrane and the stability of CaZrO3 free and supported in PVA. It is worth mentioning that under the studied conditions all variables presented significant influence in the %FAME. It is possible to conclude that under optimal conditions conversion above 96% FAME can be obtained for both catalysts under mild conditions of temperature and pressure (64°C and at atmospheric pressure). It was also found that the transesterification reaction under magnetic agitation resulted in higher mass transfer coefficients, either for the free catalyst or the supported one. This magnetic agitation prove to be more efficient then the ultrasonic agitation. The fact that the use of CaZrO3 in its free form has given the possibility of eight consecutive batch reaction cycles, which shows a high reuse capacity, without lixiviation, demonstrates its capability to be used successfully in continuous processes of biodiesel production. In conclusion, the use of a spiral catalytic membrane as a reactor presented satisfactory results (92,7 %FAME and 24 h reaction time) and thus confirming its viability to be used in the industrial production of biodiesel.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Granulation or enlargement of particle size plays an important role in industry for many reasons, such as improving the flowability of powders, reduction of environmental impact and ease to handle. In the fertilizer industry, the granulation can promote slower and more efficient absorption of the nutrients by the plants. The demand for agricultural production is increasing quickly because of the world´s population is growing fast and the Planet has a scarce agriculture resources. Only 24% of the world lands are farmable, 27% can be used just for pastures and 47% of superficies are considered unproductive. Besides of that, to respond of those demands for food will, the world needs to develop new ways to produce more in less land. So, fertilizers have a fundamental importance to the world in order to feed all these people. Fertilizers are mineral actives non renewable and their production must be based on sustainability, this way an granulation production with low costs, high quality and maximum efficiency could increase service life of the reserves. Considering the main importance of Fertilizer in the world´s food production and the criticism of this subject by new generations, the main purpose of this work was found the best conditions in granulation process to reach best granulation efficiency and hardness of particles. Granulation efficiency is an important response of the process since it determines production plant productivity, throughput, and, consequently, the size of industrial equipment, as well as the process and product quality conditions. Both of these characteristics are critical in costs and quality of fertilizers. The granulation´s experiments were performed using ordinary super phosphate from igneous Araxá rock and the evaluated variables were rotation speed, liquid phase, granulation time, fill level of the drum granulator, recycle rate, single super phosphate acidity and dosage of neutralizing. Central Composite Design (CCD) was used to choose the experimental conditions. The correlation between data and process variables was established using Multiple Regression. Images analyses made from microscopic and SEM (scanning electron microscope) with EDX, energy dispersive x-ray detector were used to explain the behavior of process granulation, the mechanism of granule´s formation and quality of granules. The results showed that the best efficiency and the best mechanical proprieties were found in different process conditions. The responses, efficiency of granulation and hardness of the product were found to be greatly dependent on the variable studies. Recycle rate about 1:1, drum´s rotation of 38% cs (critical speed), granulation time around 4-5 min, filling of drum about 11%, super phosphate acidy about 9 10% and small liquid phases showed to be a good condition of work.

Companhia Energética de Minas Gerais