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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Agora exibindo 1 - 20 de 35

Acesso aberto (Open Access)
Absorção do dióxido de carbono por resíduo de bauxita em torres de absorção
(Universidade Federal do Pará, 2013-03-04) BOTELHO, Fernando Aracati; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968
One of the most discussed environmental problems on the world scene today is global warming and its implications. Although the greenhouse effect is a natural phenomenon, the increase in emissions of gases such as CO2 from the combustion process may favor its aggravation. Following this line, there is interest in conducting research to minimize the release of this gas in the atmosphere. This work aims to study the process of absorption of carbon dioxide by aqueous phase of bauxite residue (soda and dissolved ions in solution) in spray tower and tower saddles random (both pilot scale), as well as check the pH change in this absorption process to both towers. Evaluate pH change and CO2 absorption capacity by considering the following variables: the type of absorption tower, using the supernatant as the absorbent means and the use of the suspension heated by resistances. The results showed that the suspension of bauxite residue absorbed significant amount of CO2, both the spray tower as the tower saddles. The average absorption rate was around 8.42% for the spray tower and 9.34% for the tower saddles. The ability carbonating the suspension of 27%-p was about 33.3 kg CO2 per tonne of waste and there was a substantial reduction of the alkalinity of the residue by reaction with gaseous effluents with a mean decrease of 4.0 and 3.5 pH units for the tower saddles and sprinkler respectively.
Acesso aberto (Open Access)
Adsorção de corantes básicos empregados na indústria têxtil por argila: cinética e perfil de equílibrio
(Universidade Federal do Pará, 2015-10-14) AZEVEDO, Luiz Eduardo Chaves de; VIEIRA, Melissa Gurgel Adeodato; http://lattes.cnpq.br/6611289393148830; CARVALHO, Samira Maria Leão de; http://lattes.cnpq.br/6192858937057152
In this work, the adsorption of textile basic dyes by clay was studied in aqueous solutions and batch system. Clay was obtained from Icoaraci, metropolitan region of Belém, Pará (Brazil) and was used without treatment (A-BRU) and treated by sedimentation (A-TRA). The basic dyes studies were: Basic Yellow 28, Basic Blue 26 (Blue Victory), Basic Yellow 02 (Auramine), Basic Red 01 (Rhodamine 6G) and Basic Orange 02. The clays were characterized by chemical (CTC and charge density), physical (particle size analysis, SBET and He picnometry), thermal (ATG and DTA), mineralogical and morphological analyses (XRD, SEM/EDS and FTIR). Adsorption experiments were carried out to investigate affinity between dyes and clays (qualitative test), initial concentration and pH effects of the dye solutions. The adsorption kinetics data were analyzed by theoretical models. The adsorption equilibrium data were fitted by Langmuir and Freundlich models. The thermodynamic parameters were calculated from adsorption equilibrium data at different temperatures. The concentration of clay particles in the A-TRA increased 100% after sedimentation. In the clay composition minerals as quartzo, kaolinite and illite /muscovite were identified. The SBET increased from the 22.38 m².g-1 (A-BRU) to 33.02 m².g-1 (A-TRA). Significant differences between the values of density and total pore volume of the clays were not observed. Comparatively, the CTC value of the A-TRA increased 300%. The clay surfaces are predominantly negatives, according to the charge density results (Q). There were no significant differences between the thermal analysis results of the samples. From the adsorption affinity tests the more reactive dyes were the Basic Yellow 2 (BY2) and Basic Blue 26 (BB26) and the adsorbent with improved performance was A-TRA. The adsorption kinetics data were well fitted by pseudo-second order (BY2/A-TRA) and intraparticle diffusion models (A-TRA/BB26). The adsorption equilibrium data were well fitted by Langmuir (BY2/A-TRA) and Freundlich (A-TRA/BB26) models. The parameters of the mathematic models indicated that the adsorption is favorable. The thermodynamic parameters showed that the adsorption processes investigated are spontaneous and endothermic.
Acesso aberto (Open Access)
Adsorção de CU2+ em alumina de transição obtida a partir da mistura de gibbsita e hidróxido de alumínio gel
(Universidade Federal do Pará, 2015-09-30) PINHEIRO, Darllan do Rosário; MARTELLI, Marlice Cruz; http://lattes.cnpq.br/1213009262936026
Alumina is one of the most important oxides in the ceramic industry, being used mainly in the form of calcined alumina or fused applied, among other ways, as adsorbent material. In this work is a transition alumina production method from a mixture of gibbsite, from the Bayer process, gel and aluminum hydroxide, from the reaction of aluminum sulfate and ammonium hydroxide targeting the application as an adsorbent material for removing Cu2 + in aqueous solution. Adsorption conditions including contact time and pH were investigated. Assays were carried out at 30 ° C and 50 ° C, in which 1 g of alumina produced was subjected to contact with 100 ml of an aqueous solution containing Cu2 +. The concentrations of the aqueous solutions employed were 100, 200, 400, 800, 1600 and 2000 ppm copper sulphate solution. The characterization of copper sulfate solutions was performed in UV spectrophotometry and characterization of the material produced was carried out by XRD, EDX and BET surface area. Evaluated the contact time to achieve the adsorption equilibrium which is optimized time 15 min. The effect of pH on the adsorption shows that the adsorption temperature increases there is an increased pH compared with the pH of the initial solution of copper sulfate. The isotherms of Langmuir and Freundlich had satisfactory results for adsorption, and the Langmuir isotherm that better fits the adsorption data. Through the equilibrium isotherms it was found that the material produced has adsorption capacity for Cu2 + ion.
Acesso aberto (Open Access)
Análise experimental da secagem do corante hidrossolúvel de urucum (Bixa orellana L.) em leito de jorro
(Universidade Federal do Pará, 2016-02-15) SILVA, Adriano Gomes Paixão da; FARIA, Lênio José Guerreiro de; http://lattes.cnpq.br/7428609361678173; https://orcid.org/0000-0002-9534-9998; COSTA, Cristiane Maria Leal; http://lattes.cnpq.br/0581730621014796
The water-soluble dye annatto norbixin salt is mainly used in the pharmaceuticals industry, cosmetics and especially in industrial food sector in breads, sausages, yogurts, confectionery, pasta, cheese, sandwich cookies, juice concentrates and others. The low toxicity and its coloring ability make the annatto norbixin salt a very attractive and convenient dye, replacing many synthetic dyes. These characteristics encourage to seek ways to facilitate the use of natural dyes in the various segments of industry, as well as promoting research about obtaining in order to get a product with the desired characteristics and qualities. This work it is carried out experimental analysis of water soluble dye drying annatto (Bixa orellana L.) in spouted bed, using cassava starch as a carrier agent and particles of low-density poliestileno (LDPE) as an inert material. The extraction of the dye was carried out by immersion and agitation of annatto seeds in 5% potassium hydroxide solution. It is statistically evaluated the influence of the drying process input variables, temperature (70, 80 and 90 ° C), atomization pressure (10, 15 and 20 psi), and atomization of the suspension flow (10, 7 and 8.5 mL/min) one the response variables: efficiency (η), moisture content (U) and norbixin salt content of the dye powder (S), using Statistica®7.0 application. The estimate of the optimum condition of drying within the analyzed experimental area is determined based on the input variables applying the concept of global desirability. The conditions in this work, it was reached a optimum value of Desirability Function considered as very good and that matches the temperature of the drying air 82.6 °C, atomization pressure of 13.7 psi and flow of suspension dye 10 ml / min, generating satisfactory values for the response variables corresponding to 71.69 % yield, 0.06161 g H2O/g dry solids of moisture and 2.3605 % dye of norbixin salt powder.
Acesso aberto (Open Access)
Aproveitamento da torta de dendê (elaeis guineenses) para a produção do acetato de celulose
(Universidade Federal do Pará, 2022-06-17) MORAES JUNIOR, Elio Ferreira de; ALMEIDA, Ossalin de; http://lattes.cnpq.br/7040173036131516; HTTPS://ORCID.ORG/0000-0003-3895-0952; CHAVES NETO, Antônio Maia de Jesus; http://lattes.cnpq.br/3507474637884699; https://orcid.org/0000-0002-9730-3512
This work aimed to produce cellulose acetate (CA) from in natura palm kernel pie (TD) it was subjected to different chemical treatments: bleaching (TDB), alkaline (TDA) and alkaline followed by bleaching (TDAB). The CA was obtained from the different materials by homogeneous acetylation in the mass ratios: 1:5, 1:10 and 1:15 (acetic acid), 1:15 (acetic anhydride) and 1:0.1 (sulfuric acid). Reactions were carried out at room temperature under constant stirring (120 rpm, 24 h). The characterization was performed using scanning electron microscopy (SEM), infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H and 13C-NMR) techniques. The degree of substitution (GS) was determined by titration with 0.25 mol.L-1 sodium hydroxide solution, being confirmed by FTIR and 1H and 13C NMR with different GS. The CA synthesized from the combination of pre-treatments presented DS of 2.81 (TDAB5), 3.02 (TDAB10) and 3.07 (TDAB15), being, therefore, it characterized as cellulose triacetate, corresponding to the yield values (m/m) of 50.45%, 65.5% and 97.21%. By analyzing the results, TDAB15 was the best condition for obtaining cellulose acetate from palm kernel cake.
Acesso aberto (Open Access)
Argila caulinita da região norte do Brasil: caracterização e aplicação como adsorvente de compostos orgânicos (btx) e oxiânions de cromo hexavalente
(Universidade Federal do Pará, 2014-06-26) MIRANDA, Edgar de Souza; VIEIRA, Melissa Gurgel Adeodato; http://lattes.cnpq.br/6611289393148830; CARVALHO, Samira Maria Leão de; http://lattes.cnpq.br/6192858937057152
Clays have a high technical-economic viability for diverse industrial applications. In certain regions of State of Pará, clays are abundant and their extraction occurs intensively, usually used in manufactures of ceramic artifacts. The use of modified clays as adsorbents in the remediation of contaminated water has been the subject of several studies. In this work, a kaolinite characterization and its application as adsorbent in the form "in natura" heat treated in the adsorption of BTX and after modification of its surface by catônico surfactant (HDTMA-Br) was studied, as adsorbent of hexavalent chromium oxyanions. In the study of adsorption of chromium (VI) a factorial design (DCCR) was used, applying variables such as pH and concentrations of surfactant. The clay from Icoaraci District (PA) was classified by sieving, as (NBR 7181). Fractions "in natura" (FR-NAT) and modified (FR-ORG) and (FR-TR), with particles smaller than 44 m and the modified materials were submitted to analysis: x- ray diffraction (XRD), x-ray fluorescence, ATG/DTA, electron microscopy (SEM), determination of surface area (SBET), mercury porosimetry, CTC and pH (pcz). The composition of the clay material were identified: quartz, kaolinite and illite/muscovite (I/M); SiO2 (59.6%) and Al2O3 (17.5%). The property values of: 21.8 SBET m2/g; pore size distribution in the mesopore and macropore region; CTC 17 (meq/100 g) and pHPCZ value equal to 4.3. The analyzes of ATG/DTA samples of organoclays showed that there was loading the clay surface by surfactant (HDTMA-Br). Samples thermally modified natural clay and showed no affinity for organic compounds (BTX). In the study of the adsorption of hexavalent chromium, a factorial design (CCRD) based on pH and concentration of surfactant was used. The adsorption of hexavalent chromium by natural clay was not satisfactory, but the chemically modified clay reached satisfactory values. From the statistical analysis of the adsorption data, only the concentration of cationic surfactant produced statistically significant effects in removing the adsorbate.
Acesso aberto (Open Access)
Avaliação do processo de produção de etanol pela fermentação do caldo de mandiocaba (Manihot esculenta Crantz)
(Universidade Federal do Pará, 2013-02-28) SOUZA, Leiliane do Socorro Sodré de; FRANÇA, Luiz Ferreira de; http://lattes.cnpq.br/6545345391702172
The physico-chemical characteristics identified at sweet cassava root, was: moistures (%), fiber (%), protein (%), ash (%), total lipids (%), reducing sugars and total reducing sugars (%); the sap extract from sweet cassava root was characterized by pH, soluble solids (%), glucose and titratable acidity. This study used the yeast Saccharomyces cerevisiae PE-2. Was realized 15 tests that followed the conditions determined by the experimental design of Box- Behnken, with 3 independent variables: temperature (oC) (X1), pH (X2) and concentration of inoculum (g/L) (X3). The statistical analysis was performed with p>0,05. Through the analysis of variance (ANOVA) was proposed a second order polynomial model to the alcohol content (ºGl), and by analysis of response surfaces it was determined the optimum condition to the fermentation of sap extract from sweet cassava root without addition of nutrients, on original substrate concentration of it (6,46 g/L): 28ºC (temperature), 4,88 (pH) and 10 g/L (inoculum concentration). Under these conditions a test was conducted, which aimed to raise the curves of cell growth (yeast), CO2 production, consumption of sugars and ethanol production, to better understand the process of fermentation broth of sweet cassava. Through the cellular growth curve was determined the duration of the exponential phase, using the method of linear regression; this step in this study occurred at different time intervals. The value found to μm was 0,05 h-1.
Acesso aberto (Open Access)
Caracterização e proposta de tratamento de lixiviados de resíduos de madeira
(Universidade Federal do Pará, 2012-09-24) ALMEIDA JÚNIOR, Walter Figueiredo de; SILVA, Denilson Luz da; http://lattes.cnpq.br/4241759369873376
This is a characterization study and proposal for treatment of woodwaste leachate produced in laboratory. Woodwaste leachate or stormwater runoff or log yard runoff are generated when wood waste resulting fi-om the manufacturing process, are arranged inappropriately, making the interaction with water, generally climate rainfall, resulting in a dark colored liquid which can contam n a number of components with the potential negative impact on aquatic environments. The effluent generated in the laboratory was studied by two separate experiments. In Experiment A, in polyethylene bottles, were mixed water and sawdust in proportion 9:1, in an open system and room temperature for 90 days. At times 0, 1, 5, 10, 20, 30, 45, 60, 75, 80 and 90 days, the solution was filtered and brought to the laboratory for analysis. In Experiment B, stored in a plastic container (bucket type) about 5 kg of sawdust, where the bottom was adapted a drain to collect effluent. This system was exposed to sunlight and rainfall climate, so as to simulate the minimum conditions for generation ofleachate fi-om a waste pile of wood in the real case. In both observed the generation of a liquid amber beige to dark, strong characteristic odor, slightly acidic (pH 5.53 to 6.97), high oxygen demand (BOD 17 — 310 mg.L-1; COD 857 — 3161 mg.L-1; DO 0.63 — 5.56 mg.L-1), high charges of organic matter (TC 170.93 — 425.19 mg.L-1, TOC 167.66 — 415.66 mg.L-1 and TIC 2.22 — 34.05 mg.L-1), high solids concentrations (SS 10 — 23 mL.L-1; TSS 463 — 1330 mg.L-1; TDS 31 — 640 mg.L-1 and turbidity 10.0 — 638.5 UNT). Due to these characteristics has been proposed a physicochemical treatment for runoff produced by combining the processes of coagulation/flocculation and oxidation with potassium permanganate, which resulted, respectively, in the removal of 20.95% and 88.53 % of COD, 98.18% and 43.31% of color, 40.45% and 98.16 of turbidity, 65.71% and 100% of TSS, per process. The overall removal efficiency of the proposed treatment was 90.93% of the values of COD, 98.97% in true color values, 98.90% of turbidity and 100.00% values of TSS.
Acesso aberto (Open Access)
Caracterização mineralogica do agregado obtido a partir da lama vermelha do processo bayer
(Universidade Federal do Pará, 2014-12-27) REIS, André Wilson da Cruz; NEVES, Roberto de Freitas; http://lattes.cnpq.br/9559386620588673; MARTELLI, Marlice Cruz; http://lattes.cnpq.br/1213009262936026
The industrial activities increasingly generate a lot of waste and by-products being stored in the environment, with physicochemical characteristics which can most often be reused. The red mud residue from the Bayer process, is being studied for use in the production of synthetic aggregates, which aims to replace natural aggregates used in construction. This work studies the physical, chemical and mineralogical characteristics of the aggregates synthesized from a mixture of red mud, clay, sand and charcoal in 4 compositions, varying amounts of red mud and clay. The raw materials were pretreated and analyzed by X-ray fluorescence, X - ray diffraction, thermal and particle size analysis. The samples were calcined at 1200 °C for 4 hours. Then subjected to analysis by X-ray diffraction, X- ray fluorescence, differential thermal analysis and scanning for characterization and physical tests electron microscopy. For the study of the observation of synthetic mullite aggregate specimens embedded in resin, and adding 5% HF for 3 to 4 minutes were made. The material presented after sintering, apparent specific gravity average below 2 g\cm3 main crystalline phases by XRD quartz and hematite and the presence of mullite from the HF treatment can be observed.
Acesso aberto (Open Access)
Craqueamento termocatalítico da borra de neutralização do óleo de palma (Elaeis guineensis) em escala piloto
(Universidade Federal do Pará, 2013-06-21) ABREU, Deise Hellen Soares de; MACHADO, Nelio Teixeira; http://lattes.cnpq.br/5698208558551065; BORGES, Luiz Eduardo Pizarro; http://lattes.cnpq.br/8756886156388456
The byproducts of oil refining industries and biodiesel, as the dregs of neutralization are quite extensive and due to their low economic value and purity are a problem for these industries in the culling and disposal, are of fundamental interest for the use of this research reject. Therefore, this work aims to investigate a viable, economic and environmental fate of this byproduct using Termocatalítico Cracking Process of Neutralization Sludge Palm Oil (Elaeis guineensis Jaqc) pilot scale using 5, 10 and 15% sodium carbonate (Na2CO3) as catalyst and final temperatures of 440 ° C and 420 ° C. The sludge was obtained by the neutralization process and subjected to a dehydration and characterized as the catalyst was dried in an oven and characterized in relation to the X-ray diffraction, Thermal Gravimetric Analysis (TGA) and Differential Thermal Analysis (TDA). Five tests were performed in termocatalítico cracking Cracking Pilot Plant (THERMTEK / FEQ / UFPA) which consists in a reactor with mechanical agitation and capacity 125 liters, and the dynamics of the process and distillation of cracking. The organic liquid product (PLO), samples of the dynamics of the process and the distillation fractions were characterized according to each standard required by ANP N°65 and analyzed by IR and NMR. After analysis of the results showed that the efficiency of the process increases with temperature and catalyst and the feedstock provides products of low acidity and good characteristics for use as fuel. By analyzing the thermodynamic realized that some of the process parameters such as viscosity, flash point and density decrease with increasing time and temperature, forming lighter hydrocarbons. Regarding distillation fractions in the heavier tracks resemble diesel oil in most of the parameters required by the ANP Nº 65.
Acesso aberto (Open Access)
Craqueamento termocatalítico do óleo de fritura residual
(Universidade Federal do Pará, 2013-06-20) SANTOS, Wenderson Gomes dos; MACHADO, Nelio Teixeira; http://lattes.cnpq.br/5698208558551065; BORGES, Luiz Eduardo Pizarro; http://lattes.cnpq.br/8756886156388456
This paper studied the cracking process termocatalítico the frying oil in bench and pilot scales, varying the percentage of sodium carbonate catalyst 5 and 10% m / m of raw material used and temperature of 440 º C. The objective was to obtain hydrocarbon mixtures rich in diesel fraction. The frying oil was neutralized and dried characterized in relation to the Acid Value, Saponification, Viscosity, Density and Refractive Index. After cracking, the liquid product obtained was purified by decanting the aqueous phase and simple filtration bench scale. This product was fractionated by fractional distillation and condensate were collected in a separating funnel according to the distillation range of gasoline (40ºC-175ºC), kerosene (175ºC-235ºC), light diesel (235°C-305°C) and heavy diesel (305°C-400°C). Were characterized both physical as chemical composition of the liquid products and their fractions. We also carried out the evolution of the cracking process in pilot scale, with the behavior of physical characteristics and chemical composition of the product formed during the cracking process. The results showed that the catalyst sodium carbonate supplied products of low acidity and good characteristics for use as fuel. The variation in the percentage of catalyst significantly influences the physical and chemical composition of both the product and its fractions. It was found also that the cracking termocatalítico the frying oil promotes the formation of hydrocarbons in rich fraction of diesel (19.16% and 41.18% light diesel heavy diesel to the test with 10% Na2CO3 and 13, 53% light and heavy diesel 52.73% for the test with 5% Na2CO3 ). The time intervals generate the final cracking fuel with low acid content and physicochemical properties according to the specified standard mineral diesel.
Acesso aberto (Open Access)
Desacidificação de frações destiladas de produto líquido orgânico do craqueamento termo-catalítico de óleos vegetais via adsorção em y-alumina e lama vermelha ativada
(Universidade Federal do Pará, 2015-04-16) COSTA, Karen Marcela Barros da; BORGES, Luiz Eduardo Pizarro; http://lattes.cnpq.br/8756886156388456; MACHADO, Nelio Teixeira; http://lattes.cnpq.br/5698208558551065
This paper studied the adsorption of residual free fatty acids (carboxylic acids) present in distilled fractions from the Liquid Organic Product (PLO) obtained by thermal catalytic cracking of vegetable oil. The objective was to deacidification of distilled fractions obtained from the distillation of the PLO. The experiments were performed using different distilled fractions using three different adsorbents, y-Alumina, Red Mud Thermally activated (400 °C) and Red mud chemically activated with solutions of HCl in different concentrations (0.25, 1 and 2M). The adsorbent capacity relative to adsorption of free fatty acids was evaluated by means of kinetic studies, measuring the change in concentration of free fatty acids present before and after adsorption by determining the Acid Number. The results indicated that increasing the initial concentration of acids decreases the adsorption capacity of the adsorbent, showing that the process is less effective at higher concentrations. For experiments with different percentages of adsorbents seen that when using 0.5% adsorbent to obtain greater efficiency in the removal of fatty acids, which decreases with increasing percentage of adsorbent. The most efficient adsorbent was red mud activated with 1M HCl, which was obtained a reduction of 98% of the fatty acids to a sample with an initial acid number of 4 mg KOH/g. Mathematical modeling indicated that the kinetic model that best represents the process was the Pseudo Second- Order. Therefore, the results show that the adsorbents used are mostly effective in the removal of free fatty acids and the initial concentration of acids in the sample has a direct effect on the performance of adsorption thereof.
Acesso aberto (Open Access)
Dinâmica molecular de armazenamento de H2 em nanotubos de carbono sob ação de campo elétrico externo
(Universidade Federal do Pará, 2016-01-27) AIRES, Júlio Cesar Nunes; CHAVES NETO, Antônio Maia de Jesus; http://lattes.cnpq.br/3507474637884699; https://orcid.org/0000-0002-9730-3512
Several thermodynamic properties were analyzed through computer simulations systems, in which we used a carbon nanotube a gas molecule (H2), the very low initial temperature of 10-3K order. This H2 molecule was chosen because of its properties are of great application in different branches of study, the physical sciences, chemical and biological. The H2 molecule is individually relaxed inside and outside the nanotube during simulations. Each system was under the influence of a uniform electric field parallel to the carbon nanotube and the thermal effect on the initial temperature in the simulations generating the evanescent effect. Due to the electric field, the molecule rotates at a low temperature in orbit about the carbon nanotube while increasing the value of the electric field permitted the variation of the radius of the orbit atoms. The calculated amounts were the following: kinetic energy, potential energy, the total energy, temperature variation in situ, the molar entropy and the mean radius of the orbit atoms. The data suggest the action of the electric field is sufficient only to generate the evanescent attractive potential and this system can be used as a sensor selector atoms.
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)
O estudo da docagem e dinâmica molecular de potenciais fármacos: rodatina, scedapina C e cequinadolina A, utilizados no tratamento da SARS-COV-2
(Universidade Federal do Pará, 2022-05-06) LIMA, Antonio Sanderlei dos Santos; ALMEIDA, Ossalin de; http://lattes.cnpq.br/7040173036131516; HTTPS://ORCID.ORG/0000-0003-3895-0952; CHAVES NETO, Antônio Maia de Jesus; http://lattes.cnpq.br/3507474637884699; https://orcid.org/0000-0002-9730-3512
Due to the study of new drugs to combat the SARS-COV-2 virus, which is causing the COVID-19 pandemic. In this work, we address the use of three drugs (Rhodatin, Scedapin C and Scequinadoline A) as possible inhibitors of SARS-CoV-2, as they have several interactive properties, showing potential to be used in the treatment of COVID19 disease. Molecular docking provided information about the affinity energy which was -8.186, -9.617, -7.866, -7.601, -7.527 kcal/mol, for the best conformations with Scequinadoline A. Molecular couplings and affinity energy showed the residues of the site macrostructures, and analyzed the electrostatic potential map to predict some promising candidates for virus antagonists. Molecular dynamics techniques were used, where the targets were the external structures of the virus, but specifically the envelope protein, main protease, Spike glycoprotein. Using the GROMACS 2021.2 modules, the results showed that the ligands have characteristics of interaction over time. Molecular dynamics provided values between 1.5 and 4.5Å for the mean square deviation of atomic positions. Among the results obtained through molecular dynamics, it was noted that the hydrogen bonds, when compared to the calculation of the square root of the mean square deviation, underwent a change in the amount of hydrogen bonds in the bonding process, according to the proximity of the ligand used to filter out unrealistic poses in the snap, and also improved the accuracy of binding energy calculation. Analysis of molecular couplings showed that the S-gly active site residues strongly interacted with the three drugs. The reuse of these drugs in the fight against SARSCoV-2 may be candidates via virus antagonists, which if confirmed through experimental approaches, can contribute to the resolution of the global crisis of the COVID-19 pandemic.
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 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)
Estudo de quantificação de compostos fenólicos, avaliação de atividades antioxidantes e modelagem molecular da croton pullei var. Glabrior lanj
(Universidade Federal do Pará, 2021-04-16) SOUZA, Alexandre Augusto Moraes de; COSTA, Renato Araújo da; http://lattes.cnpq.br/6578338979054891; BRASIL, Davi do Socorro Barros; http://lattes.cnpq.br/0931007460545219
The study aimed to evaluate, from extracts, the yield (on a dry basis), quantify the total polyphenols, evaluate the antioxidant activity, perform a theoretical NMR research of the julocrotine, crotonimide A and crotonimide B structures, from Croton pullei VAR. glabrior LANJ. and evaluate these molecules in molecular docking against the enzymes Candida albicans (PDB ID: 1AI9), Staphylococcus aureus (PDB ID: 1DIM) and Salmonella thyphimurium (PDB ID: 4URM). A conventional extraction was performed using a stainless-steel extractor and three-factor planning (temperature, particle size and solid/liquid ratio) and three Box-Behnken levels, to determine which variables were influential in the responses. The quantification of total polyphenols was performed according to the Folin-Ciocalteu methodology. For the antioxidant analysis, the IC50 method was applied. And the theoretical NMR study was carried out via DFT, where the computational methods DFT/B3LYP/cc-pvDZ and DFT/B3LYP/6-31 G* were applied to obtain the chemical displacements (δH and δC), to compare to the experimental ones and thus provide which computational method is the most efficient. Yields vary between 5.57 and 10.61. In the quantification of total polyphenols, there was a variation between 101.33 and 308.84 mg EAG/g. The minimum and maximum antioxidant values were 94.74% and 98.97%. In general, the DFT/B3LYP/cc-pvDZ methodology was more efficient compared to the analyzed structures. The molecules showed hydrogen bonds with residues Lys 57 (A), Arg 56 (A), Cys37, Gly38, Asp62, Gly193, Tyr342, Gly56, Arg37, Tyr128, Arg56, Thr58 (A), Gly114 (A) and Thr 127.
Acesso aberto (Open Access)
Estudo do processo de craqueamento termocatalítico do óleo de palma (Elaeis guineensis) com lama vermelha calcinada e alumina ativada em reatores de bancada e batelada
(Universidade Federal do Pará, 2015-05-29) LOURENÇO, Rafael Martins; BORGES, Luiz Eduardo Pizarro; http://lattes.cnpq.br/8756886156388456; MACHADO, Nelio Teixeira; http://lattes.cnpq.br/5698208558551065
In the present work was to study the thermal catalytic cracking process palm oil for biofuel production. In the development of this study were performed in crackings Bench and Semipilot. Initially, basic catalysts in cracking tests were performed (Red Mud; Red Mud Calcined at 550 ° C; Red Mud Calcined at 800C; Red Mud Calcined at 1000 ° C; Activated Alumina (AA) with NaOH 20% solution and Activated Alumina (AA) NaOH solution 30%) and acid (not activated alumina) in bench scale using as raw palm oil. Before the mentioned catalysts are used in thermal catalytics crackings, they were subjected to the following tests: Fourier Transform Infrared (FT-IR); Scanning Electron Microscopy (SEM); X-ray Diffraction (XRD) and BET in order to characterize them. The results of the bench scale showed that the cracked products Gross (PCB's) achieved in thermal catalytics oil crackings using as a catalyst 15% Red Mud Calcined at 800 ° C and 15% AA by NaOH 20% solution, had a significant reduction in their Acidity Index (IA's) compared to the IA's of heat and thermal catalytics crackings used with other catalysts. In Semipilot Scale the thermal catalytics crackings were developed with the best results obtained, Bench Scale, between the Red Mud’s Calcined or not in different concentrations (15% of Red Mud Calcined 800 ° C) and between the Activated Aluminas or not at various concentrations (AA with 15% NaOH solution at 20%) compared to IA's, in addition to the thermal cracking which was also reproduced on the scale. Some of the products obtained in Semipilot Scale was submitted to distillation in Bench Scale to obtain fractions corresponding to the tracks: gasoline, kerosene, light diesel and heavy diesel. The RMN analysis of 13C, held on the heat crackings and diesel thermal catalytic with 15% Red Mud Calcined at 800 °C proves that they are basically formed from long chain fatty acids. Moreover, the GC-MS performed in the cut of gasoline range (40 °C- 175 °C) showed that the three gasolines analyzed showed the formation of paraffinic hydrocarbons, olefinic and naphthenic.
Acesso aberto (Open Access)
Estudo eletroquímico de ligas metálicas alumínio-silício em meio ácido
(Universidade Federal do Pará, 2012-03-30) SANTOS, Luana Santana dos; CARDOSO FILHO, José Carlos; http://lattes.cnpq.br/7033790503322903
The alloys based on aluminum-silicon have low specific weight, good mechanical strength and corrosion resistance, have been widely used as substitutes for some ferrous alloys in manufacturing parts for various industries. In this research we studied the electrochemical behavior of aluminum and aluminum-silicon alloys 0.3 and 0.7% by mass in electrolytes sulfuric acid and hydrochloric acid, both at 0.1 mol/L. The results of electrochemical techniques showed that the Si caused a shift to more positive values corrosion potential was observed a region of passivity anodic curves of the electrodes in sulfuric acid, this phenomenon was not observed in hydrochloric acid. The Nyquist diagrams show two arcs, a capacitive region of high frequencies related to the formation of the layer oxidizes and an inductive at low frequencies attributed to adsorption of anions on the metal surface, the similarities in the diagrams show that the electrochemical phenomena are identical and independent addition of Si. The impedance diagrams also showed low polarization resistance of the alloys Al-Si. Considering only the electrochemical studies it can be stated that the electrodes did not show significant differences between themselves and susceptibility to corrosion in these acidic solutions does not imply a negative feature to your application.