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Conselho Nacional de Desenvolvimento Científico e Tecnológico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Factors such as global climate change, environmental pollution and reduction of the availability of fossil energy resources make renewable energy a topic of growing importance, and in this context biomass has been considered the major current source of clean energy. Among the technologies of energy conversion from biomass, pyrolysis is a promising tool as it generates products with high energy content in solid (charcoal), liquid (bio-oil) and gas phases. These products have diverse application: energy production, refinery input and in the preparation or activated charcoal (solid product). In the context presented, this work investigates the reaction of pyrolysis of some residues of Brazilian agribusiness (cashew nut shells, sugarcane straw, chicken litter and sawdust) as a way to obtain products of higher energy level. For that, the samples were pyrolyzed in a stainless steel reactor externally heated. The effect of varying temperature and pressure on yield and quality of the products obtained from cashew nut shells was investigated. For the other biomass, the reaction was performed at different temperatures: 300 C, 400 ° C, 500 º C, 600 º C and 700 º C at atmospheric pressure. The products obtained were charcoal, bio-oil, aqueous phase and pyrolytic gas. The experimental results showed that the increase in pyrolysis temperature resulted in decreasing yield of solid product obtained. The yield of charcoal ranged between (19.83 - 27.61) % for cashew nut shells, (27.65 - 47.35) % for sugarcane straw, (37.13 - 53.38) % for chicken litter and (26.86 - 45.29) % for sawdust. The highest oil yield was obtained at 500 ° C for chicken litter (9.50 wt.%) and sawdust (10.00 wt.%). The yield of biooil from cashew nut shells reached its peak at 600 º C (37.83 wt.%). Sugarcane straw produced no measurable amount of oil in the reaction conditions studied.

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Universidade Federal de Goiás - Goiânia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

The São Paulo Brasília Pipeline (OSBRA), owed by PETROBRAS, starts at the Planalto Refinery (REPLAN) and supplies gasoline, Diesel oil and liquefied petroleum gas (LPG) to the mid-west region of Brazil. The pipeline is 786 kilometers long with diameter of 20 inches in its first segment and 178 kilometers with 12 inches of diameter in the second. The fuels are pumped by seven unmanned pump stations and are delivered to five tank farms. Previously, these products were pumped into the pipeline in batches, those of Diesel or LPG located between gasoline batches. These sequences allowed the dilution of the transmix, which are mixtures generated between two products during the pipeline transportation, to the pure product tanks, keeping compliance to the former standards. The Diesel/gasoline transmix were mixed direct to pure product tanks of Diesel or gasoline. The LPG/gasoline transmix were submitted to flashing in a vessel before to be mixed into gasoline tanks or LPG spheres. The National Petroleum Agency (ANP) changed the Diesel and LPG standards, in 2001 and 2004 respectively. The properties which were altered are the flash point of the Diesel and the residues of the LPG. This new regulation turned the OSBRA installations unable to dilute the whole transmix volumes generated during pipeline transportation. Part of the transmix had to be sent back to the REPLAN, increasing the costs and making the LPG pipeline transportation unprofitable. To overcome this situation, a new product was developed the QINTER. The QINTER can be mixed in suitable rates either to Diesel or to gasoline keeping the compliance of these fuels to the new standards at the receiving tanks. The QINTER has been pumped into the pipeline between the batches of Diesel oil and gasoline since then. The standard solution to treat the mixture created between LPG and gasoline batches, which is a distillation tower, was studied, but it showed to be unprofitable and it would compel changes to the existing working schedule time, from Monday to Friday (6:00am to 10:00pm) to a 24:00h/day continuous work. In this thesis, there were studied three new configurations which would need lower capital investment and would not change the working schedule time. It was used the process simulator Petrox, developed by the Research Center of PETROBRAS, to carry out the necessary process simulations. In the first configuration it was studied the change of the actual treatment system operation, from batches to a steady state way, as well as it was made a search of the optimum pair of pressure and temperature operation of the existing system. In the second configuration it was included a new flash vessel in series with the existing flash vessel. In the third configuration it was added two flash vessels and two new heat exchanges to the existing system. The simulations which were carried out showed that in the three configurations studied the compliance with the new standards were achieved. Nevertheless, in the first configuration would be needed more time than the available in the current working schedule to treat the whole transmix generated in the pipeline transportation. The second and the third configurations provided the necessary capacity to treat the transmix. The advantage of the last one is the residue of its vapor stream to be within the standards. This feature turns the operational work easier, because it eliminates the necessity of controlling the proportion in that the vapor stream is mixed with LPG to keep compliance with the standards. Therefore, the desired target, to find technical and operational solution to treat the transmix volumes generated in the OSBRA transportation, was attained.

Oil by-products, such as lubricating oils, gasoline, diesel and their constituting organic compounds, pollutants hard to degrade, are constantly released into the hydrographic basins as a result of different industrial processes, accounting for serious pollution problems to sea life. An increasing concern at the environment has intensified the study of techniques for the removal of these polluting charges from liquid effluents. In this respect, adsorption has drawn much attention because it presents itself as an effective, money-saving, highly selective method at molecular level besides having low energy consumption. Besides the concern at the efficacy of the removal of pollutants, the final destination of the adsorbing solid once its life-span is over, must also be taken into consideration. Thus, the research for low-cost adsorbing materials likely to be reused for other purposes has been intensified, having their aggregate value increased by the adsorption process. Once sugar-cane bagasse is abundant throughout Brazil, it has a high surface area and is highly hydrophobic, its use as a bioadsorbent for organic contaminants has aroused the interest of the academic community. Thus, the aim of the present work is to assess the adsorption ability of sugar-cane bagasse for the removal of oil by-products contaminating liquid effluents, with the aim of treating those and carrying out the concomitant energetic enrichment of bagasse for its later use as fuel in boilers. This way, adsorption experiments in agitated reactor were carried out to investigate the factors which influence and optimize the bioadsorption of oil by-product contaminants on sugar-cane bagasse and to understand the mechanisms of this process. Therefore, the assessment of the kinetic curves and of the adsorption isotherms of gasoline and of n-heptane in aqueous solutions at room temperature was carried out. The results show the promising trait of bagasse as an adsorbent, being able to adsorb up to 99 % of gasoline and 90 % of n-heptane contained in solution containing about 5 % of these contaminants. Furthermore, the adsorption kinetics of gasoline is very quick (with equilibrium times lower than 5 minutes) and adsorption is favourable and takes place in multi layers. When describing experimental isotherms the models of Langmuir, Freundlich, Langmuir-Freundlich, Jovanovic-Freundlich, Dual-Site Langmuir Model (DSL) and Multispace Adsorption Model (MSAM) were assessed. The DSL and MSAM models are the ones which better describe the isotherms for gasoline adsorption, however, they are still poor to describe the isotherms of n-heptane adsorption.

Spouted bed has been studied intensively because of its potential of application in several processes. Identification and characterization of flow regimes in spouted bed based on visual observation have been reported in literature. However, the characterization of flow regimes based on visual observation is not either usual or possible in industrial equipments. Therefore, the aim this thesis is to design an experimental apparatus dotted a data acquisition system in order to identify the flow regime of the spouted bed. The experimental data obtained from the experimental apparatus were compared with data obtained from simulation studies by using a computational fluid dynamic technique (CFD). Soybean and cotton seeds were used in this study. The spouted bed was build in stainless steel with the following dimensions: H = 85 cm, Dc = 21 cm, Di = 3.5 cm e θ = 60°. The pressure drop fluctuations in the bed were acquired on line by using the LabVIEW® 7.1 software. A 100 Hz sampling frequency was used in all runs. Graphical analysis of the pressure fluctuations versus time showed to be not appropriate for identification of the flow regimes. On the other hand, the use of the fast Fourier transform technique (FFT) over the pressure drop signals yielded a power spectrum. Based on this power spectrum it was possible to propose an effective identification criterion. By using this criterion it was possible to identify clearly all flow regimes in the bed: fixed, transition and spouting. Simulation results used for comparison with experimental data were obtained by using the commercial package FLUENT® 6.1.18. The porosity profiles and the characteristic curve of the spouted bed were calculated by using an Eulerian multiphase model. The comparisons showed a very good agreement between experimental and simulation results.

Brazil holds second place in world production of dicalcium phosphate, which represents the main source of phosphorus for complementing the mineral salt that makes up the daily feed for cattle, hogs and fowls. Considering the fact that the increase in consumption of phosphates due to the increased annual consumption of meat by the world population, development of the technology necessary to guarantee quality and productivity has become imperative in order to supply this competitive market. The requirement for BUNGE Fertilizantes S.A. to accompany the world trend, reflected by client suggestions for sales of bulk quantities, originated the search for a new technology to produce microgranulated dicalcium phosphate. Due to characteristics adverse to forming the microgranulated dicalcium phosphate grain (particle size, monocalcium phosphate and residual acidity), it has become necessary to apply a final product classification process to guarantee compliance with the physical specifications of the material at the moment of expediting to clients. The purpose of this dissertation is to perform a study of the classification system used for fluidization, seeking scale-up information for construction of an industrial unit to be installed at the Cajati Facilities of BUNGE Fertilizantes. Fluidization is utilized commercially in a wide range of processes such as: catalytic operations, cooling, drying, recovery, etc, it utilizes the elutriation effect in wich the relatively small components are entrained by the gas flow for physical classification of materials. Within this concept an effort was made to quantify the effects of operational and dimensional variables of the fluidized bed system: porosity of the distribuition screen, residence time and freeboard angle. In accordance with the main experimental results, a statistical analyses was made by multiple regression, thus obtaining parameters related to the isolated variables and the interactions among them. It was observed that the operational and dimensional conditions that promote the best Separation and Recovery efficiencies for the system were those for which the screen porosity was 11 %, the residence time was 5,34 minutes and the freeboard angle was 33,62o. On the basis of the optimum data obtained from the fluidization pilot system, an industrial system was designed for the Cajati Facilities, having classification capacity of microgranulated dicalcium phosphate of 100 Tons/h. The resultant Separation end Recovery efficiencies of the industrial system demonstrate an excellent application of technology for FBC (dicalcium phosphate) classification and the model obtained from the pilot project precisely predicts the efficiencies for industrial systems. Thus, the mathematic model obtained from the pilot plant can be used as a reference for design and scale-up of microgranulated dicalcium phosphate industrial classification units, having characteristics similar to those studied in this dissertation.

Slaked lime is a suspension of hydrated lime in water that can contain up to 40% of solids in suspension. It is a cheap base with high alkaline content. It is used in a variety of industrial applications such as process of treatment of water and sewerage, treatment of waste, in the stages of sugar clarification, in gas cleaning systems, among several other processes. The quality of the suspensions of slaked lime depends on the quality of lime used and on a careful choice of the conditions during the hydration process. A high quality slaked lime is a product with a small quantity of insoluble residues, high specific surface area, high alkaline content, small particle size and low viscosity. Therefore, the objective of this work was study the best conditions of temperature, concentration (relation lime/water), lime particle size, and agitation to produce a superior slaked lime. A statistic analysis was performed using the results obtained in order to optimize the operational conditions of the hydration process. It was observed that the use of small lime particle size, a temperature around 74 °C and concentrations between 217 g/L e 228 g/L minimize the amount of insoluble residue. The use of the same particle size and temperature, with a concentration around 175 g/L contributes to increase of the specific surface area of calcium hydroxide. It was observed that the degree of agitation does not interfere in any slaked lime properties investigated. The majority of the slaked lime suspensions presented a pseudoplastic fluid behavior. It was verified that the samples with high reactivity and high surface area presented smaller agglomeration observed by images of scanning electron microscopy. Parametric optimization disclosed the conditions necessary to produce a slaked lime suspension of fine quality.

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Batch processes are usually systems for which defined raw materials quantities are combined in specific recipe during a designated time to produce intermediate or final high added value products and generating the smallest waste of raw material. Most of the batch processes with economic interest are inherently nonlinear, making the control task a challange. The iterative learning control is a methodology that involves the use of learning strategies in order to achieve the better reference trajectory tracking and disturbance rejection. Thus, the addressedmethodology uses important features for the control of industrial batch plants, as the disturbances rejection, the inclusion of restrictions on the control variables making control more realistic, added to the ability to track reference trajectories over the batch, among others. In this context, this work presents the iterative learning control methodology successfully applied to various plants with distinct features, ranging from minimum and nonminimal phase SISO and MIMO linear systems and nonlinear systems. Comparative studies about the proposed control quality against classical control methods were also performed to show the degree of increasing performance due to the iteractive learning strategy. The results of the use of iterative learning control strategies looked promising since they provide versatility and tuning with easy, making the controller intuitive. For LTI minimum phase processes, the learning was almost immediate. The iterative learning controller was able to compensate for nonminimum phase behavior resulting from delay or nonminimum phase zeros, leading to a perfect tracking of the reference trajectory. The use of the methodology for nonlinear plants control was evaluated for reaction systems in which are tried two different ways to get the learning matrix, such as FIR models and locally linearized models. The iterative learning control methodology brought improvement on the setpoint tracking in all studied cases.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

The purpose of the present study was to develop a Neem (Azadirachta indica) leaves processing technology an enzymatic inactivator (fast pre-heating device, sapecador ) as a pilot project following by drying process in a tray dryer with heating air. The best operational condition consisted on fast pre-heating ( sapeco ) for 5 min running the device in 200.1 rpm. The final product resulted in olive green coloration, brittle aspect and absence of peroxidase enzyme. The initial moisture of leaves was reduced from 88.33% (wet base) to 24.81% (wb) after 5 min of fast pre-heating process ( sapeco ). Using a try drier with hot air stream (60ºC) at 0.55 m/s. After 120 min of drying process the leaves moisture content, in wet base, was 5% approximately, that is an appropriate value for storage. After grinding of dried leaves, 80.45% of particles has size less than 0.149 mm (100 mesh Tyler). In the moisture content of 5.86%, in wet base, superficial contraction of 19.6% on leaf surface has occurred.

The soy lecithin, usually known as being a phosphorous group or phospholipids of the rude oil of soy. He/she possesses in his/her composition not only molecules lipids containing match molecules, but they count considerable amounts of chlorophylls, carotenes and brown substances. All these possess specific spectra of absorptions that for spectrophotometric can be quantified, therefore they supply characteristic coloration to the lecithin. The coloration is a brown darkness, a lot of times denominated of amber, it can be decisive factor in the choice and use of that natural emulsificant. Therefore, the coloration of the soy lecithin can be reduced through the addition of compositions chemical peroxides, which possess to structures (OO-²) of radical peroxides in their molecules, such as the peroxides of hydrogen (inorganic chemical bleach) and the benzoíla peroxides (organic chemical bleach). The application of the peroxides of hydrogen and of the benzyl peroxides as clarificant of the soy lecithin was studied and certain the minimum concentration was 0,5%, to the maximum of 2,0%. The analyses accomplished in the soy lecithin and in the samples treated with the bleaching agents were regarding the humidity tenors, saponification index, stability oxidative, composed chlorophylls, carotenes and brown substances. A preliminary test was accomplished soon in the beginning of the study, to determine which among ten solvents organic solubilized the lecithin to the maximum. The hexane was chosen as the appropriate for solubilization the soy lecithin in the physiochemical analyses of carotenes, brown substances and stability oxidative, because it possesses better custom/benefice, it is used thoroughly in the extraction of rude oil and it possesses characteristic of 100% of apolarity. The results obtained in the physiochemical analyses of the lecithin of added soy of peroxide of hydrogen to 35% in the proportions of 0,5%, 1,0%, 1,5% and 2,0% were: index bass of saponification, gradual increase in the stability oxidative for the decrease in the tenors of primary and secondary structures of the peroxidation reaction, degradation of compositions chlorophylls, decrease of the carotenes and of brown substances. To the peroxide of hydrogen to be decomposed it generates gas oxygen and free water, however the analysis on the humidity tenor was not satisfactory. And, regarding the results regarding the addition of peroxide of benzyl anidre 65% is had that the increase in the concentration of that it caused elevation of the saponification index, increase of the stability oxidative of the lecithin, suave degradation of composed chlorophylls and carotenes, besides reducing the amount of brown substances. Finally, at the end of the study the clarification terminology was determined as appropriate to describe the despigmentation of the soy lecithin with peroxide of hydrogen and benzyl peroxide visually e quantitivity with physic-chemistry analyses realized.

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Due to its high performance and great processing capacity, the rotary dryer has an important role in drying processes of various products. The rotary dryer is based in a cylindrical drum, slightly inclined in relation to the horizontal line that rotates in slow speed. The inner side of drum is equipped with flights that collect the solids on the bottom of the drum and are transported to an angular position where they fall as a raining curtain through a hot air stream. The modeling of the process was carried out by application of the mass and energy conservation equations to the fluid and particulate phases in infinitesimal element of volume of dryer. In a previous work at the Chemical Engineering School of the Federal University of Uberlândia-MG, it was developed a new model to describe the distributions of air s and fertilizer s humidity and temperature throughout the dryer, being validated with experimental data for granulated single superphosphate (SSPG). The comparison of results obtained from the model proposed by ARRUDA (2008) demonstrated a good agreement with the experimental data obtained from a small scale unit (diameter 0.3m and length 1.5m). However, the model proposed by ARRUDA (2008) demonstrated significant deviation when compared to experimental results obtained by FERNANDES (2008) in an industrial scale dryer (diameter 3.0m and length 30m), although these deviations were probably caused by measurements imprecision, false air (losses) assumptions and/or potential different behavior between the material used by ARRUDA (2008) and the one used by FERNANDES (2008). Aiming to improve the model s predictability, the main objective of this work was to analyze the influence of the following parameters: heat transfer coefficient, material drying rate and solid and air specific heat, through parametric sensitivity study using experimental design evaluated for solid moisture and temperature and air humidity and temperature responses, obtained by fertilizers drying model in rotary dryers countercurrent proposed by ARRUDA (2008). The variance analysis together with the surface plots demonstrated that each studied parameters has a statistic result, although in some results were observed a strong influence that features an important meaning in physical terms. The results obtained from the parametric analysis demonstrate the importance of knowing the most significant parameters in order to describe them accurately, which will contribute to aim in depth knowledge about the drying process enabling efficiency increase on already existent equipment and more accuracy on projects of new equipment.