Dissertações em Engenharia Química (Mestrado) - PPGEQ/ITEC

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2309

O Mestrado Acadêmico iniciou-se em 1992 e pertence ao Programa de Pós-Graduação em Engenharia Química (PPGEQ) do Instituto de Tecnologia (ITEC) da Universidade Federal do Pará (UFPA).

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Acesso aberto (Open Access)
Absorção de gases da queima de combustíveis fósseis em torre de recheio estruturado utilizando lama vermelha
(Universidade Federal do Pará, 2013-03-11) SANTOS, Iara Ferreira; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968; SOUZA, Célio Augusto Gomes de; http://lattes.cnpq.br/0800747860976046
The production of alumina from the Bayer process produces 1-3 tons of waste per ton of aluminum. This residue is known red mud, compound of minerals insoluble in concentrated sodium hydroxide, hematite and other iron oxides, quartz and titanium oxides. The red mud has in its composition varied levels of NaOH, depending on the specific industrial plant used. The purpose of this study is to evaluate the process of absorption of gases from a boiler countercurrent with a suspension of red mud, in a spray tower and a packed column. Experiments were performed varying the type of absorption tower, temperature of the liquid phase and solids content in liquid phase to evaluate the reduction in content of gases of combustion in the output of absorption tower and pH variation with time of operation, it was possible to identify the time required for the occurrence of red mud neutralization, and also a reduction in the content of carbon dioxide, thereunto were performed measurements of the concentrations of gasesin the input and output packed column, and also measurements of temperature and pH. The absorption of CO2 existing in the gases of combustion for suspension of red mud occurs by the carbonation process, where the gas reacts with NaOH present in red mud, with water as catalyst. The results obtained after the experiments were satisfactory, and it was concluded that the process performed in absorption towers is efficient for pH reduction of red mud and reducing the content of CO2 freed to atmosphere, providing a double profit for the environment.
Acesso aberto (Open Access)
Adsorção de ácido 2,4-diclorofenoxiacético em carvão ativado granular de resíduos de buriti (mauritia flexuosa l.): estudo em batelada e leito fixo. Orientador: Lênio José Guerreiro de Faria. 2024. 135 f.
(Universidade Federal do Pará, 2024-12-27) ARAÚJO, Raíssa Cristine Santos de; FARIA, Lênio José Guerreiro de; http://lattes.cnpq.br/7428609361678173
Pesticides, when applied responsibly, are essential for agricultural productivity, however, depending on their dosage or frequency of exposure, they can cause numerous problems for human health, in addition to the contamination of soil and surface or underground water. Following this problem, this manuscript aimed to evaluate the adsorption of the herbicide 2,4- dichlorophenoxyacetic acid (2,4-D) using physically activated granular carbon (CAT) and chemically activated granular carbon with ZnCl2 (CAQ) produced from the endocarp and endosperm of buriti (Mauritia flexuosa L.), typical fruit from the Amazon region. The adsorbents were characterized in terms their textural and physicochemical properties through the percentage of ash, moisture, specific surface area (SBET), pore volume (Vtotal), by SEM/EDS, XRD, FTIR spectroscopy, TGA/DTA, the surface functional groups, point of zero charge (pHPCZ) and the surface pH of the carbon. Batch adsorption tests were carried out to elucidate the influence of activated carbon dosage and the effect of solution pH. The adsorption mechanisms and the nature of the process were investigated by studying the kinetics, equilibrium and thermodynamics for the coal with the highest performance. The best results for adsorbate removal percentage were CAT (96.93%) and CAQ (92.46%) and the adsorption capacity CAT (29.00 mg.g-1 ) and CAQ (137.70 mg.g -1 ) within 24 hours, pH 2.0 and dosage of 0.25 g of CAT and 0.05 g of CAQ. The CAQ adsorbent showed superior results in removal and adsorption capacity, with its kinetics fitting the pseudo-second order model, with external diffusion being the determining stage of the adsorption process. The isotherms were satisfactorily fitted to the Sips model. The thermodynamic data revealed the endothermic, physical and spontaneous nature of the adsorption process. The adsorption on fixed bed confirmed that the adsorvent mass, concentration of solution and the inlet flow were influent in the adsorption process, highlighting the efficiency of simultaneous optimization tecnic, within the experimental region explored in this work. Both interactions showed that the charcoals produced present high yield, with the development of pores and surface groups, and excellent performance in removing the 2,4-D herbicide, promising substitutes for commercial carbons.
Acesso aberto (Open Access)
Adsorção monocomponente e binária de antiinflamatórios não esteroidais (Ibuprofeno e Diclofenaco) do meio aquoso por carvão ativado de resíduos da castanha-do-Brasil (Bertholletia excelsa H.B.K.)
(Universidade Federal do Pará, 2024-09-12) SILVA, João Paulo Sousa da; VIEIRA, Melissa Gurgel Adeodato; http://lattes.cnpq.br/6611289393148830; CARVALHO, Samira Maria Leão de; http://lattes.cnpq.br/6192858937057152
Emerging contaminants (ECs) present in low concentrations have caused damage to water bodies. This study investigated the single-component and binary adsorption of sodium ibuprofen (IBU) and diclofenac (DIC) using activated carbon (AC) produced from Brazil nut shells. The single-component adsorption process of IBU and DIC by AC was denoted as (AC_IBU and AC_DIC), and the binary adsorption process was denoted as (AC_IBU+DIC). The AC was synthesized by chemical activation using phosphoric acid (H3PO4) as the activating agent. The AC was characterized through physical, chemical, and textural analyses, including moisture content, ash content, yield, Thermogravimetric Analysis/Differential Thermal Analysis (TGA/DTA), X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy (SEM/EDS), surface pH, point of zero charge (pHPZC), Boehm titration, and nitrogen (N2) adsorption/desorption at 77 K. The AC presented moisture and ash contents of 8.62% and 4.2%, respectively. The XRD analysis confirmed the amorphous nature of the AC, while FT-IR, surface pH, and pHPZC analyses indicated its acidic nature. The specific surface area (SBET) of the AC was 1,383.624 m².g-1 , with a predominance of micropores (VMIC=77.88%). From the analysis of the Central Composite Rotational Design (CCRD), the experimental conditions for the kinetic and equilibrium adsorption tests were defined for single-component adsorption: (i) IBU (pH = 6.1; initial adsorbate concentration, C0 = 50 mg.L-1 ; adsorbent dosage, DA = 0.5 g.L-1 ) and (ii) DIC (pH = 5.5; C0 = 50 mg.L-1 ; DA = 0.5 g.L-1 ). In the single-component adsorption kinetics study, the pseudofirst-order (PFO) and pseudo-second-order (PSO) models resulted in the best fits to the experimental data for the AC_IBU and AC_DIC adsorption processes, respectively, and external mass transfer was the rate-controlling step of the processes. In the singlecomponent adsorption equilibrium study, the Langmuir, Freundlich, Sips, DubininRadushkevich, and Redlich-Peterson isotherms were investigated. The Sips and Freundlich models showed the best correlations for AC_IBU and AC_DIC, respectively. The thermodynamic parameters calculated from the adsorption isotherms showed that the AC_IBU and AC_DIC processes are spontaneous, favorable, and exothermic. The CCRD, the experimental conditions for the binary adsorption kinetics and equilibrium tests were defined: (i) AC_IBU+DIC (C0IBU = 50 mg.L -1 ; C0DIC = 50 mg.L-1 ; DA= 0.5 g.L-1 ). Binary adsorption indicated, through the calculation of the separation factor parameter, that the adsorption preference order by the adsorbent is IBU > DIC, and the interaction between the adsorbates was antagonistic. In the binary adsorption process, the PSO model was well fitted to the experimental kinetics data of IBU and DIC; the intraparticle diffusion (IPD) kinetic models and the Boyd equation were correlated with the experimental data, and external mass transfer was the rate-controlling step of the adsorption processes. The isotherms of binary adsorption (AC_IBU+DIC) at different temperatures (26 ºC, 45 ºC, and 55 ºC) showed inflection points, and after these inflection points, there was an increase in the adsorption capacity values of AC (qe). The qe values of binary adsorption (AC_IBU+DIC) were lower than the qe values of the singlecomponent adsorption processes of the adsorbates IBU and DIC. The reduction percentages of the qe values were approximately 35% to 48% for IBU and about 52% to 53% for DIC.
Acesso aberto (Open Access)
Avaliação da influência da natureza da matriz sólida sobre a extração supercrítica de óleos vegetais
(Universidade Federal do Pará, 2013-05-10) COSTA, João Fernando Alves; FRANÇA, Luiz Ferreira de; http://lattes.cnpq.br/6545345391702172
The extraction of substances from solid substrates both low and high pressures involves at least two phases, a solid and another fluid. The content of the solute in each phase is expressed in terms of the volume of phase and / or volume of solvent. Then, by modeling the interfacial mass transfer it requires a partition coefficient. In general, the simplest way to address this problem is to model the phases separately. The mechanism predominant mass transfer can vary from system to system. For some substrates higher resistance may be in the solid phase and for others it is in the fluid phase. As the interface concentrations for each phase are represented by different variable, phases have to be modeled separately. However, depending on the system, there may be a transfer mechanism predominated over the other, and many effects can be discarded for simplification of the model. The utilization of simpler mathematical models requires a combination of variables for definition of parameters that can represent the phenomenon. In this work the extraction curves were fitted to a model which describes the interfacial mass transfer like a first order kinetics, since the constant of the extraction rate is the unique adjustment parameter. It has been proposed that the adjustment parameter depends on the solubility of solute in the supercritical solvent and on the solid substratum characteristics. To avail that, extraction experiments with babaçu, powder açaí and pupunha pulp using super-critic carbon dioxide at 20, 25 and 30 MPa and temperature of 50°C have been carried out. The results showed that the experimental data fit well to a model with a constant characteristic of each material, with values 4.1983 x 10-5 m/kg∙s to babaçu, 4.2258 x 10-5 m/kg∙s to pupunha pulp, to 10-5 m/kg∙s to powder açaí.
Acesso aberto (Open Access)
Avaliação das condições de secagem no rendimento e na qualidade do óleo de linhaça (Linum usitatissimum L.)
(Universidade Federal do Pará, 2011-06-20) VALENTE, Maria da Conceição da Costa; COSTA, Cristiane Maria Leal; http://lattes.cnpq.br/0581730621014796; SOUZA, Célio Augusto Gomes de; http://lattes.cnpq.br/0800747860976046
From Asian origin flaxseed (Linum usitatissimum L.) and belongs to the linaceae family and it is obtained from flax. It is considered a functional food, because it contains substances that may prevent diseases such as degenerative and cardiovascular diseases. Flaxseeds are still a major lignans source, that are photochemical compounds similar estrogen, which it may performs cancer-preventative. In addition to being one of the richest sources of α-linolenic acid oil and soluble fibre. The drying is a unit operation, in general, usually means removal of relatively small amounts of water from material by evaporation or by sublimation, applying heat under control conditions. Aiming to analyze the behavior of flax seeds during the drying operation, this study aimed to perform the experimental design and statistically analyze the results used to quantify the influence of air temperature (T), drying time (t) fluidization air velocity (Uf) and solids loading (Cs) on the humidity ratio (Xr), oil yield (Rend.) and the parameters oleochemicals. The estimate of the optimal point of operation was determined according to the input variables by applying the concept of global desirability. Among the conditions set out in this work, the optimal value of the function you want and when T is shifted to high level (72 oC), Uf is shifted to high level (0,83 m/s), t you for the minimum (3h ) and Cs for the secondary level (500 g), thus obtaining: 0.126 to Xr, 36,92 % for Rend.; 4.51 mg KOH/g for IA, 22,52meq O2/g IP and 0,31% for DC. We obtained the sorption isotherms of flaxseed at temperatures 40, 60 and 80 °C. Six mathematical models were applied to analyze the experimental data. The enthalpy and differential entropy were determined by appying Clausius-Clapeyron and Gibbs-Helmholtz equation, respectively. Peleg model and GAB model showed the best fit to experimental data. The enthalpy-entropy compensation theory was applied to the isotherms, indicating that they are enthalpy - controlled. The flaxseed Drying were evaluated in a fixed and fluidized bed dryer, the experimental runs were done at temperatures 40, 60 and 80 °C. Five mathematical models were evaluated and the Midilli et al. model was found to be the best model for describing the flaxseeds drying behavior. It was observed that the effective diffusivity for the flaxseeds increased with increasing drying air temperature. The diffusivity dependence by temperature was described by the Arrhenius equation. It was estimated the activation energy.
Acesso aberto (Open Access)
Avaliação do potencial biotecnológico para o tratamento de um minério de ouro de uma mina do estado do Amapá
(Universidade Federal do Pará, 2016-04-08) GRANGEIRO, Luana Cardoso; BEVILAQUA, Denise; http://lattes.cnpq.br/9156111627025084; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505
One of the most commonly used pre-treatments prior conventional cyanidation is the biooxidation. This technical is a biological process capable of promote solubilization of metals such as copper, iron through the oxidative action of microorganisms in metal sulfides and it is applied as a pretreatment in the cyanidation process to reduce free cyanide consumption making this a feasible and economic process. Thus, the aim of this work was to study the best biotechnology route for the pretreatment of the gold ore in order to reduce cyanide consumption during the convencional cyanidation and increasing the gold recovery. For this purpose, biological tests has been investigated at laboratory scale on a gold ore sample coming from Estado do Amapá, Brazil (90 g/ton). Bacterial cultures utilised in the biological tests of 20 days consisted of Acidithiobacillus ferrooxidans-LRe Acidithiobacillus thiooxidans-LR. The biooxidated samples were submitted to cyanidation tests for gold recovery and tests of consumption of cyanide. Experimental studies demonstrate that after 24h leaching time by direct cyanidation, the gold recovery was 93% (32 mg/L) with a cyanide consumption of 2,84 kg.t-1, while the best gold extraction between biooxidated samples was from bioreactor R2 with 87% (30 mg/L), and the cyanide consumption of 2,64 kg.t-1. Experimental results have shown the technical feasibility of the biooxidative prior to convencional leaching for for reducing the consumption of reagent cyanide.
Acesso aberto (Open Access)
Caracterização, análise fluidodinâmica e secagem de sementes de painço em leito de jorro
(Universidade Federal do Pará, 2014-05-16) NASCIMENTO, Lidiane Diniz do; COSTA, Cristiane Maria Leal; http://lattes.cnpq.br/0581730621014796; FARIA, Lênio José Guerreiro de; http://lattes.cnpq.br/7428609361678173
S. italica seeds were analyzed in chemical, physical and qualitative aspects and then the fluidynamics was evaluated at ambient temperature, for different loads of material in two spouted bed configurations: conical (500, 800, 1100 and 1400 g ) and conventional ( 1300, 1700 and 2100 g). From the experimental data it was found that the particles were suitable for the system used, so the operating parameters of the spouted bed were collected , which were compared with their theoretical values calculated by empirical correlations available in literature. According to experimental conditions, it was necessary to choose only one of the configurations of spouted bed, so it was decided to operate the conventional spouted bed. For the seed drying kinetics only the optimal load (1700g) was utilized and the temperatures used were 44 , 65 and 86 °C, verifying the absence of constant drying rate, indicating that drying was controlled by diffusion mechanisms. The effective moisture diffusivity was estimated, resulting in the range from 0.7729x10-11 to 2.3189x10-11 and the relationship between the temperature and the effective moisture diffusivity was described by Arrhenius equation, providing an activation energy of 24,86 kJ/mol. The mathematical models that best described the drying curve were Diffusion Approximation, Page and Midilli et al. Furthermore, a rotational central composite design was applied with the objective of evaluating the influence of the independent variables time (X1) and temperature (X2) on the responses moisture ratio (XR), germination (G) and speed germination index (SGI) . The chosen answers are necessaries in the seeds quality control, as in the case of the moisture content during the storage. The G and SGI responses are indicative of the physiological state of the seeds, which are also important, in accordance with the purpose of the product. Through statistical analysis, for a confidence interval of 95%, it was found that XR and SGI were influenced only by X1, X2 and X22 , while G was statistically affected by X2 and X22 . The effects for all responses were negative , indicating that SGI and XR decrease with increasing of temperature and drying time. The answer G decreases with increasing of temperature. Quadratic models were proposed by the statistical analyzes, reaching good correlation coefficients (R2); 0.9632 (XR), 0.8998 (G) and 0.9724 (SGI). Then, the optimal value of the foxtail millet drying process was determined, using the concept of Desirability Function, which was corresponding to a drying time of 121 min at a temperature of 64 ° C, getting seeds with 82.99% of germination; speed germination index of 29.33 (dimensionless) and final moisture content of 11%.
Acesso aberto (Open Access)
Determinação de parâmetros de transferência de massa do processo de extração supercrítica
(Universidade Federal do Pará, 2013-03-01) SANTANA, Ádina Lima de; MACHADO, Nélio Teixeira; http://lattes.cnpq.br/5698208558551065; ARAÚJO, Marilena Emmi; http://lattes.cnpq.br/8983914018546682
Supercritical fluid extraction of liquid and solid materials sparked interest for industrial applications in recent decades, particularly under the concept of green chemistry and biorefineries, so it is essential to make a modeling of this process in order to optimize and simulate operating conditions process. The objective of this work consists in determining the parameters of mass transfer of supercritical extraction of solid matrix by employing carbon dioxide as solvent, from kinetic data extraction and five systematic evaluation of mathematical models to describe the kinetics extraction of oils from the peel and pulp of buriti, oil from açaí and oleoresin from turmeric, measured in Supercritical Extraction Laboratory, Faculty of Chemical Engineering (UFPA) in order to contribute to the study of scale-up and production cost analysis. Were evaluated the models of Tan and Liou, Goto et al. (1993), Martinez et al. (2003), Esquível et al. (1999), and Sovová (1994). The extraction kinetics modeling was performed using computer applicatives developed and validated in this work from different experimental data published in the literature. Facing 40 kinetic measurements with different extraction equipment, bed settings, types of raw materials, preparation of materials, pressure and temperature and other process parameters (especially income and global flow solvent), was built an overview of results ability of the models on the mass transfer in more different curves describing the overall extraction. Generally, the model Goto et al. (1993) and Sovová (1994) showed the best predictions to experimental data of raw materials treated in this work with smaller values of chi-square, relative errors, range and standard error and R2 values close to unity.
Acesso aberto (Open Access)
Determinação de propriedades termofísicas e estudo do equilíbrio líquido-líquido de sistemas envolvendo líquidos iônicos próticos
(Universidade Federal do Pará, 2017-03-24) GOMES, Rossimar dos Santos; SILVA, Silvana Mattedi e; http://lattes.cnpq.br/8741124364246075; SANTOS, Geormenny Rocha dos; http://lattes.cnpq.br/0844662601945669
This work consisted of the synthesis of protic ionic liquids (Ethyl 2-hydroxyethylammonium propionate [E2HEAP][PR], Diethylammonium propionate, [DEA][PR] and Butylammonium propionate, [BA][PR] and determination of density and viscosity of protic ionic liquids [DEA] [PR] and [BA] [PR] pure and the binary systems formed by these ionic liquids + water at different temperatures and atmospheric pressure. The density data were determined using a digital densimeter and viscosity by the viscometer, both of Anton Paar, the experimental results were used to obtain excess molar volume (𝑉𝑚𝐸), apparent molar volume (𝑉∅,1), viscosity deviation (Δη) and excess Gibbs free energy (ΔGE), being the results correlated with the Redlich-Kister or Redlich-Meyer equation. The results were compared and discussed based on the molecular interactions between the studied componentes. It was also made the study of liquid-liquid equilibrium data (LLE) for systems, involving 1-butanol + water + protic ionic liquids: [E2HEA][PR] or [DEA][PR] or [BA][PR] K and atmospheric pressure, being the systems quantified by the gravimetric method. The quality of the equilibrium data was verified by the semi-empirical methods of Othmer-Tobias and Hand. From the obtained equilibrium data, the values of the distribution coefficient found indicated the hydrophilic behavior of the LIs studied. Data liquid–liquid equilibrium was correlated by the NRTL and UNIQUAC thermodynamic models, which was observed that the NRTL model correlated in a more satisfactory way the results presenting global deviation of 1,56% for NRTL and 1,78% for UNIQUAC.
Acesso aberto (Open Access)
Estudo comparativo dos processos de separação na obtenção do biodiesel de óleo de palma bruto (Elaeis guineensis, Jacq)
(Universidade Federal do Pará, 2014-05-05) RIBEIRO, Haroldo Jorge da Silva; ARAÚJO, Marilena Emmi; http://lattes.cnpq.br/8983914018546682; MACHADO, Nelio Teixeira; http://lattes.cnpq.br/5698208558551065
This work investigated the influence of the separation processes on the yield and properties relating to the quality of biodiesel from crude palm oil ( Elaeis guineensis, Jacq ) obtained in laboratory scale , such as decantation , centrifugation , evaporation , washing and dehydration, where the following operating conditions are used : the settling time ( sludge/neutral oil ) - 120 minutes at 50 ° C; settling time used for washing the neutral oil 60, 90 and 120 minutes at 50 °C; H2O percentages used in washing the neutral oil 10%, 20% and 30% ( m./m.); temperatures centrifugation for separating the neutral/oil sludge and washings neutral oil 40, 50 and 60 °C; temperature and pressure range of dehydration of neutral oil and biodiesel and 80 °C from 480,0 to 80,0 mbar respectively; temperature and pressure in the evaporation of excess ethanol 75 °C and 213,3 and 146,6 respectively March; the settling time of biodiesel/glycerol system and washes 60, 90 and 180 minutes at 50 °C; operating temperature used in the centrifuge separation system biodiesel/glycerin 50 °C; H2O percentage of biodiesel used for washing by centrifugation 20% relative to the ester phase. The results found that neutralization in general was satisfactory as generated about 10% of blurs, highlighting the Experiment 1 that generated about 84,6% by weight of neutral oil. Washes in 90 minutes (Exp. 1) and 20% water (exp.2) showed the best performance for the separation by settling, while in the process of centrifugation and washing better separation occurred at 40 and 50 ° C respectively. In relation to the evaporation of ethanol, the best percentage in alcohol was obtained at 80 °C and 1466 mbar. Regarding the separation of phases rich in glycerol esters and the process of centrifugation at 50 °C led to a better quality biodiesel, however, the best yields were observed in the biodiesel from the settling process. The final evaluation of the biodiesel produced in this study was positive, because most of the analyzed parameters is according to the official specifications.
Acesso aberto (Open Access)
Estudo da aplicação da lama vermelha como catalisador na reação de craqueamento térmico catalítico de resíduos de caixas de gordura
(Universidade Federal do Pará, 2015-07-02) EID, Janaina Guedes; BORGES, Luiz Eduardo Pizarro; http://lattes.cnpq.br/8756886156388456; MACHADO, Nelio Teixeira; http://lattes.cnpq.br/5698208558551065
This study aimed to evaluate the use of residual fat taken from retaining grease traps as an alternative raw material in the biofuel production process. The catalytic process of thermal cracking of the residual fat was carried out in bench scale and pilot using the red mud (LV) calcined at 1000 ° C as catalyst at different concentrations (5%, 10% and 15%). Organic liquids (PLO's) obtained in the cracking experiments were distilled in a bench unit, which was the production of hydrocarbon fractions in bands of light green diesel and heavy green diesel. Thus, PLO'se fractions were characterized by carrying out physicochemical and compositional analysis where the results turned out to be compared according to the specifications established by the standard of ANP No. 65 for diesel S10. The produced in the PLO counter and cracking unit using the pilot content of 5% catalyst (LV calcined at 1000 ° C) when compared with experiments using concentrations of 10% and 15% of LV showed the best results for the acid value, kinematic viscosity and density, confirming that this experiment had one of the best yields of the process and significant results regarding the physicochemical and compositional analysis. Distillation processes of the PLO's done in the distillation unit in Bench Scale showed good yields for hydrocarbon fractions in heavy green diesel range. The heavy green diesel fractions obtained after distillation of the PLO produced with 5% catalyst content showed significant yield and the best physicochemical results of all fractions obtained in this study, especially with regard to the acid value. It was confirmed through analysis of the Infrared, nuclear magnetic resonance, and gas chromatography coupled to a mass spectrometer the presence of hydrocarbons in the composition of the organic liquids.
Acesso aberto (Open Access)
Estudo da reciclagem de cinza volante para produção de agregado sintético utilizando reator de leito fixo
(Universidade Federal do Pará, 2016-02-16) PEREIRA, Luiz Felipe Silva; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968
The use of such industrial waste boiler fly ash for recycling and reuse, has intensified in recent years much for its physico-chemical characteristics that may result after the processing, in a material with good mechanical strength and can be designed for use in several areas such as construction. In this paper we obtain synthetic aggregates, after sintering process in a fixed bed reactor. For the production of aggregates pellet sewed up mixer from a mixing wheel boiler ash, clay and charcoal. After the process of ceramic sintering were measured material properties such that: porosity, density and water absorption. For the characterization of phases and mineralogical structures of the sintered material, we used the techniques of X-ray diffraction and scanning electron microscopy. Thus the contribution of this work is aimed at reducing environmental impacts, due to the possibility that the material produced has to replace natural aggregates.
Acesso aberto (Open Access)
Estudo da síntese de zeólitas tipo A, X e sodalita empregando reatores vítreos: análise dos métodos dinâmico e estático de síntese a partir de caulim residual da Região Amazônica
(Universidade Federal do Pará, 2013-12-26) SENA, Rafael dos Santos Fernandes; MARTELLI, Marlice Cruz; http://lattes.cnpq.br/1213009262936026
Kaolin processing companies generate kaolinitic residue that is stored in sedimentation ponds, occupying large physical areas. The utilization of these wastes is an important factor in the economic and the environmental terms. Here a study of the synthesis of A, X and sodalite zeolites using as raw material a kaolin waste from the Amazon Region is presented. The waste was pretreated for removal of the organic matter, comminuted and thermally activated at 750 °C for 2 hours. After selecting the optimum particle size for the synthesis by the pré-zeolitização step, two methods were tested to obtain the zeolites: dynamic and static. For the reaction mixture of the synthesis, were worked with the ratios SiO2/Al2O3 of 2/1 and 3/1 to obtain zeolites. Analyses of X-Ray Diffraction (XRD), X-Ray Fluorescence Spectroscopy (XRF) and Scanning Electron Microscopy (SEM) analyzes showed good phase formation for the NaA zeolite to the ratio 2/1, in the both sinthesys methods, dynamic and static, and without aging, and good phase formation for the NaX zeolite to the ratio 3/1, using static synthesis and with 12 hours aging. The sodalite phase was formed in the same stoichiometry of the NaX zeolite, but using static synthesis and without aging.
Acesso aberto (Open Access)
Estudo da utilização de polímeros naturais como auxiliares de floculação no tratamento de água para fins industriais
(Universidade Federal do Pará, 2012-09-27) SILVA, Juliane da Silva e; SILVA, Denilson Luz da; http://lattes.cnpq.br/4241759369873376
This work is to evaluate the effectiveness of new alternatives for use with natural species of okra (Abelmoschus esculentus) seed angico red (Anadenanthera peregrina (L.) Speng) and seed-eye dragon (Adenanthera pavonina L.) also known as ‘falso angico’, sprayed with a particle size of 0.074 mm, sieving for water treatment as natural polymers, helping the flocculation on removal of main parameters in turbidity and color through tests in the scanner equipment using Jar Test static bench adding a chemical coagulant (aluminium sulfate). The powder of polymers were obtained after washing, drying, crushing, grinding, sieving, and used in the coagulation process, flocculation and sedimentation to test the efficiency of each one, when used alone and when used in conjunction with the chemical coagulant, followed by the analysis of physical-chemical parameters pH, turbidity, apparent color, true color and temperature. The results showed that the polymer of okra presented better efficiency in removing turbidity and color compared to the same doses used with other polymers considered and when reducing the dosage of coagulant used in conjunction with the polymers, it was observed a great removal of turbidity, especially with the conjunction of coagulant and polymer of okra, with the removal efficiency of 94% of turbidity and 98% of color with optimum dosage of okra equal to 1.0 mg/L and coagulant equal to 10 mg/L. Therefore it is possible to reduce the dosage of the coagulant when used in conjunction with the auxiliary flocculation, as the polymer of okra can be used for water treatment and facing the possibility of multiple economic and ecological uses in industry.
Acesso aberto (Open Access)
Estudo das variáveis operacionais dos processos de separação na produção de biodiesel, a partir do óleo de palma bruto (Elaeis guineensis, Jacq) em escala de laboratório
(Universidade Federal do Pará, 2013-11-14) CASTRO, Douglas Alberto Rocha de; ARAUJO, Marilena Emmi; http://lattes.cnpq.br/8983914018546682; MACHADO, Nelio Teixeira; http://lattes.cnpq.br/5698208558551065
In this work, the operational variables involved on the separation processes applied on the pre-treatment of crude palm oil (guineensis Elaeis, jacq) , as well as on the purification of biodiesel, produced by transesterification with ethanol and using NaOH as catalyst, have been investigated systematically in laboratory scale. In the pre-treatment step, the processes of Filtration and Decantation have been investigated, being the filtration of the product, carried out by neutralization at 40ºC, 50ºC and 60ºC, whereas by Decantation, it had been evaluated the temperatures of 40ºC and 60ºC in 120 minutes. After that, it was investigated the influence of the time of decantation by 60, 90 and 120 minutes on the water washing process of the neutralized oil at 40ºC and 60ºC, followed by dehydration under vacuum at 80ºC, having been investigated in this stage the influence of the pressure. After the production of biodiesel, it had been evaluated the process of Evaporation of ethanol in excess, whereas in a first step, it had been investigated the temperatures of 70 and 80 ºC, maintaining the evaporation time constant and equal to 20 minutes, within the interval of 613,30 and 80,0 mbar, and in a second step, it had been investigated the system pressures of 480,00 and 346,60 mbar. After that, it had been investigated the influence of time on the decantation process of the glycerol rich phase at 70ºC, for times of 60, 120 and 180 minutes. Afterwards, the ester rich phase has been submitted to water washing at 70ºC, for the times of 60, 90 and 120 minutes. After that, it was evaluated the efficiency of the process of centrifugation of the mixture biodiesel and glycerol at 60 and 70ºC, 2000 rpm, and a time of 15 minutes. After that, the ester rich phase has been washed with water at 60 and 70ºC, being the separation carried out by centrifugation at 60 and 70ºC. The ester rich phases, obtained by decantation and centrifugation have been submitted to dehydration under vacuum, and characterized according to the specifications of the ANP. In accordance with the experimental results, on the basis of the quality of neutral oil and process yield, it has been observed that the Filtration at 50ºC produced the best results. In relation to the evaporation of ethanol, the higher ethanol recovery was obtained by 80ºC and 346.6 mbar. In relation the separation of ester and glycerol rich phases, the process of centrifugation at 60ºC produced a biodiesel of better quality and higher yield. It was still observed, the necessity of one second step of centrifugation to minimize the losses of biodiesel in the rich phase in glycerol.
Acesso aberto (Open Access)
Extratos de sementes de gergelim preto (Sesamum indicum L) obtidos via CO2 supercrítico: isotermas de rendimento global, dados cinéticos e ajustes, ácidos graxos totais, fitosteróis e efeitos neuroprotetores
(Universidade Federal do Pará, 2013-12-17) BOTELHO, José Rafael Santos; ARAUJO, Marilena Emmi; http://lattes.cnpq.br/8983914018546682; CARVALHO JÚNIOR, Raul Nunes de; http://lattes.cnpq.br/5544305606838748
In Brazilian folk medicine, black sesame (Sesamum indicum L) seeds is one of the most important ingredients present in the tea used to treat encephalic stroke victims. Nevertheless, isolation of black sesame extracts to medicinal finality using supercritical fluid technology has not been performed. The objective of this work was to investigate some process variables of supercritical fluid extraction in black sesame to generate extracts applicable in stroke research. Two isothermal (40 and 60 °C) were explored, combined with pressures that ranged from 200-400 bar, at a constant CO2 mass flow rate of 5,9 x 10-5 kg/s. The global yields ranged from 37-53% in dry basis. The highest mass yield was obtained at 60 °C and 400 bar. The fatty acid composition comprised a high unsaturated/saturated ratio. Chromatographic analysis of phytosterol content in the high global yield extract revealed higher amounts of β-sitosterol + sitostanol, cholesterol, campesterol + campestanol + 24-methylene cholesterol, Δ-5 avenasterol and stigmasterol, while lower levels of Δ-5,24 stigmastadienol, brassicasterol, clerosterol + Δ-5-23 stigmastadienol, Δ-7 avenasterol, eritrodiol and Δ-7 stigmastenol were present in the black sesame extract. Overall extraction curves from the supercritical fluid extraction in lower and higher global yields (200 e 400 bar at 60 °C) fitted the Tan and Liou (1989), Martinez et al. (2003), Esquível et al. (1999), Goto et al. (1993) e Sovová models (1994 and 2012). The models of Tan and Liou (1989), Goto et al. (1993) and Sovová (1994 and 2012) presented the best residual sum of squares values. Pilot experiments suggest that black sesame extract is neuroprotective following endothelin-1 induced focal ischemia into the motor cortex of male adult rat, observing indications that a prejudicial cell form for the stroke`s status was inhibited by the treatment.
Acesso aberto (Open Access)
Influência da granulometria nas propriedades reológicas da polpa de bauxita pós beneficiamento
(Universidade Federal do Pará, 2015-11-13) REIS, Izabela de Nazaré Souza da Fonseca; FELIPE, Augusta Maria Paulain Ferreira; http://lattes.cnpq.br/8871741271063047; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968
The knowledge of factors that influence the rheology of bauxite pulp is necessary and important for the quality control of the flow through the pipeline process.This work evaluated the effect of different granulometric fractions (-100#+150#; -150#+200#; -200#+270#; -270#+325# and -400#) on rheology of bauxite pulp that is carried through Mineração Paragominas S/A (MPSA) pipelines. Distinct fractions of bauxite obtained by wet screening were analyzed by an X-Ray Diffractometer (XRD) to determine the mineralogical composition of the samples. The results of those analysis revealed that each fraction has a similar composition (gibsite, kaolinite, hematite, goethit and anatase) though different proportion in the fractions. The studies of rheological parameters were developed by using Thermo Scientific HAAKE Viscotester 550 and the SV1 coaxial cylinder sensor at 30ºC. Bauxite pulps, with constant solids content and equal to 50 wt% were prepared in order to simulate the actual conditions of flow through the pipeline. Testing of apparent viscosity curves versus additive concentration were carried out using sodium polyacrylate at concentrations that ranged from 0 – 1 wt% in order to determine the optimal concentration of additive necessary to stabilize the bauxite pulp. From the results found of optimal concentration of sodium polyacrylate, the hysteresis tests were performed. It was found that the smaller the average particle diameter, the greater the amount of additive is necessary to stabilize the pulp and the addition of sodium polyacrylate in the finer fraction of bauxite caused the flocculation of system. In general, the rheological behavior of the bauxite pulps with their optimal concentrations of sodium polyacrylate was shown to be non-Newtonian and time dependent, with rheopetic behavior for fractions with granulometry between 127 and 48.5 micrometers and thixotropic behavior to fine fraction with average diameter smaller than 37 micrometers. The bauxite pulp formulated with the fine particle size and without addition of sodium polyacrylate showed rheopetic behavior. It was observed, for the dispersed bauxite pulps, that the decrease the average particle size influences the size of the hysteresis area formed, causing a decrease in rheopetic behavior.
Acesso aberto (Open Access)
Influência da temperatura de calcinação na redução da hematita e na liberação do titânio na lama vermelha (resíduo do processo bayer)
(Universidade Federal do Pará, 2016-12-26) VIEGAS, Bruno Marques; MAGALHÃES, Edilson Marques; CV: http://lattes.cnpq.br/1570353513360972; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505
In this work a technological route was proposed aiming at the reduction of hematite to magnetite and the release of titanium present in red mud from Hydro Alunorte. The fluorescence and x ray diffraction analysis showed that the red mud presents in their composition approximately 5% of titanium oxide as anatase and 28% of iron oxide in the forms of hematite and goethite. Therefore, the proposed route will enable the obtainment of a material with magnetic characteristics which can be used as source of titanium after extraction of iron compounds in magnetic form. So, the reduction of the hematite to the magnetite was carried out by thermal treatment in a reducing atmosphere. To accomplish this, mixtures were made in different concentrations of red mud and charcoal. These mixtures were calcined at temperatures of 500, 600 and 1000 ° C for two hours. Then, X ray diffraction analysis were performed, which showed that the hematite was reduced to magnetite in all experimental conditions and, for the mixtures calcined at 1000 ° C, besides the formation of the magnetite, there was also the formation of maghemite. Through analysis of Raman spectroscopy and scanning electron microscopy, it was verified that for calcination temperatures of 500 to 600° C titanium remained in the free form of anatase, but for the calcination carried out at 1000° C this passed to the combined form with iron (ilmenite). The technological route allowed the formation of magnetite from the red mud, which can be extracted with the use of a magnetic separator.
Acesso aberto (Open Access)
Otimização do processo de extração do óleo essencial de priprioca (Cyperus articulatus L.) por arraste com vapor
(Universidade Federal do Pará, 2009-05-29) CORUMBÁ, Lorena Gomes; FARIA, Lênio José Guerreiro de; http://lattes.cnpq.br/7428609361678173
It is analyzed the process of extraction of the essential oil of priprioca (Cyperus articulatus L.) rhizomes experimentally with water steam, in a prototype in bench scale. Through design of experiments and response surfaces methodology, they are considered the optimal conditions to maximize the response variables yield and mustakone concentration, majority component of the essential oil of priprioca, in function of operational entrance variables of the process. The independent variables and respective levels are: load or mass of priprioca rhizomes, in grams (64, 200, 400, 600, 736); granulometry of the rhizomes, in millimeters (0,61; 1,015; 1,6; 2,19; 2,58) and extraction time, in minutes (44, 60, 90, 120, 140). Using a central composite design, with aid of the application StatisticaR 7.0, mathematical models are proposed for the responses in function of the isolated independent variables and of their combinations. It is verified that the yield in essential oil and the mustakone tenors can be fitted appropriately for second order polynomials models. They are obtained larger yield simultaneously in oil and mustakone tenors, when the load of rhizomes varies from 105 to 400 grams for extraction times between 105 and 140 minutes.
Acesso aberto (Open Access)
Processo de secagem de Morinda citrifolia L. em secador de radiação com lâmpadas refletoras, utilizando planejamento composto central rotacional
(Universidade Federal do Pará, 2015-10-16) BARROS, Hellen Carvalho; BRASIL, Davi do Socorro Barros; http://lattes.cnpq.br/0931007460545219; FARIA, Lênio José Guerreiro de; http://lattes.cnpq.br/7428609361678173
Morinda citrifolia Linn, popularly known as Noni, is a plant in the Rubiaceae, family that has been used for many centuries in popular medicine. The ancestors of the Polynesians discovered the plant and there have been numerous reports of its therapeutic and nutritional properties. For that reason, it was decided to carry out a study with the fruits of the species Morinda citrifolia L., in order to encourage use of the fruit for consumption in people’s diet, as well as to confirm its functional potential after drying. In this research, the conditions for drying Noni fruits were studied, and the phenolic compounds and antioxidant activity of the extracts obtained were assessed and quantified. In the drying process a dryer with reflecting lamps was used at the laboratory scale. In analyzing the process a statistical model was used as a basis, to quantify the effects of the entry variables in the Responses, by means of regression analyses through rotational central compound planning (PCCR) with two entry variables and five levels, employing temperature and size of the pulp as entry variables and final humidity level, antioxidant capacity and free radical sequestration activity as responses. It was observed that increasing the drying temperature led to a decrease in the final humidity level of Morinda citrifolia L fruits.The values of the responses observed varied from 0,01 a 3,50 bs, for drying; 1,32% a 38,8%, and 12,54 to 26,56(mg Eag/g) for phenolic levels.Within the experimental domain, only the variable of the isolated entry X1 (temperature) in the linear and quadratic forms were statistically influential on the Xbsresponse variable.