Effect of ecofriendly bio-based solvents on oil extraction from green coffee bean and its industrial press cake
Abstract Oil recovery, retention index, and thermodynamic parameters of green coffee beans (GCB) and its press cake (PC) extraction using bio-based solvents were investigated. The extraction parameters investigated were temperature (35 to 55 °C), type of material (coffee beans and press cake), and type of solvent (ethanol, acetone, and ethyl acetate), at a fixed solvent to solid mass ratio (5:1) (w/w). The fatty acid profile of the ethanolic extract was assessed for both GCB and PC, and compared to the oil obtained from the mechanical pressing. It was observed that higher temperatures affected positively the extraction...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Effect of cyclopentane hydrates on the stability of dodac and aot structures
In this study, hydrate formation was induced in two different systems, one obtained with the cationic surfactant DODAC (dioctadecyldimethylammonium chloride), water, mineral oil and cyclopentane, and the other with the anionic surfactant AOT (di-(2-ethylhexyl) sulfosuccinate of sodium), water and cyclopentane. The surfactants used can form emulsions or self-associated systems, depending on compositions and concentrations of the substances that are present in the samples. The stability of the hydrates formed in the different structures was analyzed. Moreover, we also perform a study of the stability of the structures obtain...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

MEASUREMENTS AND THERMODYNAMIC MODELING OF VAPOR-LIQUID EQUILIBRIA FOR BINARY SYSTEMS OF ISOPROPYL CHLOROACETATE WITH CYCLOHEXANE, ISOPROPANOL AND BENZENE AT 101.3 kPa
Abstract In this work, the vapor-liquid equilibrium experimental data for the systems of isopropyl chloroacetate + isopropanol, isopropyl chloroacetate + cyclohexane and isopropyl chloroacetate + benzene were measured by a modi fi ed Rose-type recirculating still under the pressure of 101.3 kPa. The thermodynamic consistency of the measured data was verified by the Herington and van Ness methods, respectively. The experimental data were correlated by the NRTL, Wilson, and UNIQUAC activity coefficient models, and the corresponding interaction parameters of the three models were obtained. The root-mean-square deviations bet...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Deep eutectic solvents based on betaine and propylene glycol as potential denitrification agents: a liquid-liquid equilibrium study
Abstract Two deep eutectic solvents (DES) based on betaine (B) and propylene glycol (PG) in molar ratios of 1:4 and 1:5 were prepared and their physico-chemical properties were determined. Liquid-liquid equilibria at 298.15 K and atmospheric pressure were determined for 13 quasi-three-component systems with a hydrocarbon (n-hexane, n-heptane, i-octane or toluene), solute (pyridine or thiophene) and DES (B-PG 1:4 or B-PG 1:5). Experimental phase diagrams and calculated distribution ratios showed that DESs are more suitable for denitrification than for desulfurization. The equilibria in the investigated systems were describe...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

VALORIZATION OF Solanum viarum DUNAL BY EXTRACTING BIOACTIVE COMPOUNDS FROM ROOTS AND FRUITS USING ULTRASOUND AND SUPERCRITICAL CO2
In this study, ultrasound-assisted extraction (UAE) and supercritical CO2 extraction (SFE-CO2) were applied to evaluate the extraction yield and chemical composition of fruits and roots matrices of Solanum viarum Dunal. A hydroalcoholic solution (60% ethanol/40% water, v/v) was the solvent used for UAE. For comparisons, extractions with Soxhlet and maceration were carried out. For SFE-CO2, the highest yield was obtained at 60 °C and 250 bar. For UAE, the highest yield was obtained at an ultrasound intensity of 75.11 W/cm2 and pulse cycle of 0.93. The techniques seem to be efficient for the extraction of chemical compou...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Maximization of essential oil antioxidant capacity via star anise hydrodistillation
This study shows the innovative approach of optimizing not only EO yield, but also to therapeutic activity. The product obtained follows the principle of the Pure Food and Drug Act and of eco-friendly technology. Also, the best analytical control methodology of the active principle during industrial production was also defined. The AC was found to be dependent on the extraction conditions, and the best antioxidant performance was reported after 3h of hydrodistillation time, using 500 mL distilled water and 8% dry fruits whose granulometry was inferior to 425 μ m. Although all four analytical methodologies used for asses...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Modelling ion transport in an amine solution through a nanofiltration membrane
Abstract The performance of a flat sheet polyamide nanofiltration membrane in rejection of a binary mixture of heat stable salts (acetate and sulfate) from methyl-diethanolamine (MDEA) solution was investigated. The effects of pressure and concentration of MDEA solution on rejection of acetate and sulfate ions were studied. At MDEA concentration of 20% wt. and pressure of 70 bar, 80% and 98% rejection can be obtained for acetate and sulfate ions, respectively. Membrane performance and transport coefficients were investigated using the Spiegler-Kedem-Katchalsky (SKK) model, film theory and extended Nernst-Planck (FT-ENP) mo...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Implication of microwaves on the extraction process of rice bran protein
Abstract During the processing of rice grain, a wide range of by-products are generated, including Rice Bran (RB), which presents rich composition, offering great potential for application in the food and pharmaceutical industries. Thus, the objective of this work was to evaluate the best operating variables in the extraction of rice bran protein through alkaline extraction and Microwave-Assisted Extraction (MAE). It was found that MAE, in similar conditions, resulted in a higher yield of protein extraction and protein content in the extracted material in a relatively shorter process time, when compared to the values obtai...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Polyetherimide/polyvinylpyrrolidone hollow-fiber membranes for use in hemodialysis
In this study, polyetherimide/polyvinylpyrrolidone (PEI/PVP) hollow fiber membranes (HFMs) were synthesized by the phase inversion method. The synthesized PEI/PVP membranes were characterized by morphological analysis and transport properties (hydraulic permeability and solute rejection coefficient). Their performance in uremic solutes separation was also investigated. Urea removal and clearance were measured. Surface properties were analyzed by infrared spectroscopy (FT-IR), water uptake, zeta potential and protein adsorption. The results showed that PEI/PVP membranes had transport properties comparable to those of curren...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Chemical regeneration of bone char associated with a continuous system for defluoridation of water
Abstract Sources of fluoride contaminated water are found around the world and their treatment is required before human consumption. This paper contributes to advances in the use of bone-char as an adsorbent for fluoride, associating steps of chemical regeneration and fluoride adsorption in continuous systems, thereby making feasible the multiple use of the adsorbent. Following the development of low cost treatment of water defluoridation in a fixed bed column, using bone-char, regeneration was carried out with NaOH (0.5 mol/L) solution in subsequent adsorption/desorption cycles. The continuous system was modeled applying ...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

SELECTIVE SEPARATION OF Mn(II) AND Cd(II) AS WELL AS REGENERATION OF POLYMER VIA SHEAR INDUCED DISSOCIATION COUPLING WITH ULTRAFILTRATION
Abstract The selective separation of Mn(II) and Cd(II) as well as regeneration of the complexing agent were conducted by shear induced dissociation coupling with ultrafiltration (SID-UF), and the copolymer of maleic acid and acrylic acid (PMA) was used as complexing agent. At the optimal complexation conditions, pH 6 and P/M (mass ratio of polymer to metal ions) 9, both the rejections of Mn(II) and Cd(II) arrived at more than 99%. The shear stabilities of two PMA-metal complexes at different pHs were particularly investigated using rotating disk membrane and the results indicated that critical shear rates γ c of PMA...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Study of the effect of functionalization of carbon nanotubes on gas separation
Abstract In order to improve the adsorption capacity and selectivity of CO2/CH4 and CO2/N2, we have functionalized multi-walled carbon nanotubes (MWCNT) with 3-aminopropyltriethoxysilane (APTES). The functionalized MWCNT was characterized by Fourier transform infrared (FT-IR), energy dispersive X-ray spectroscopy (EDX) and BET analysis. CO2, CH4 and N2 adsorption at two different temperatures and P
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

A new computational fluid dynamics study of a liquid-liquid hydrocyclone in the two phase case for separation of oil droplets and water
Abstract A liquid-liquid hydrocyclone, so-called de-oiling equipment, was investigated for separation of oil droplets and wastewater in an Iranian petroleum unit. To generate the geometry and the mesh of the hydrocyclone Gambit software was used. Afterwards, by taking advantage of the Euler-Lagrangian principle, the governing equations covering the motion of fluid and that of particles in the hydrocyclone were solved. Initially, it was shown that the outcomes of CFD are in agreement with experimental data, and then 15 hydrocyclones with different overflow diameters, overflow lengths and input velocities were employed for m...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Catalyst preparation methods to reduce contaminants in a high-yield purification process of multiwalled carbon nanotubes
Abstract CoMo/MgO catalysts with low loading of cobalt and molybdenum were prepared by incipient wetness impregnation and the sol-gel method for high yield production of carbon nanotubes (CNT). A detailed characterization of the catalysts, as-produced CNT and purified CNT, indicated a relationship between carbon nanotube properties, synthesis and purification steps. Excess of molybdenum in the catalyst caused a decrease in carbon yield and produced CNT with a lower degree of graphitization. Catalysts prepared by the sol-gel method and with higher molybdenum loading showed an improved interaction between cobalt and molybden...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

PREPARATION AND SIMULATION OF THE ON-LINE SiO2/S COATING FOR COKING INHIBITION IN THE INDUSTRIAL CRACKING FURNACE
Abstract Coke formation inside radiant coils is one of the main problems during thermal cracking of hydrocarbons. The on-line preparation of the coating for coking inhibition is a promising technology because it provides more flexibility to the operators on site. The SiO2/S coating was prepared on the inner surface of coils in an 8-year-served GK-VI industrial cracking furnace. The effects of the coating preparation process on the operation of TLE were studied. The coking rates of the tube with and without coating preparation were evaluated by the trend change of tube metal temperature. Simulations of the coating depositio...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

KINETIC MODELING AND EXPERIMENTAL VALIDATION OF A PHOTOCATALYTIC FLUIDIZED BED REACTOR FOR n-HEXANE DEGRADATION
Abstract This work presents a modeling procedure for a tall photocatalytic fluidized bed photoreactor used for the photocatalytic oxidation of n-hexane on the anatase TiO2 surface. The modeling strategy split the reactor into two parts: a lower dense phase, with high solids concentration behaving as a bubbling bed treated as a continuous stirred tank reactor (CSTR); and an upper lean phase of low solids concentration behaving as a plug-flow reactor (PFR). The Langmuir-type kinetic parameters were obtained for the flow rate of 1.67 × 10-4 m3 s-1 and catalyst mass of 0.1 kg. The model revealed a good adjustment with ex...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

In situ DEPOSITION OF COPPER NANOPARTICLES ON POLYETHYLENE TEREPHTHALATE FILTERS AND ANTIBACTERIAL TESTING AGAINST Escherichia coli AND Salmonella enterica
This study reports a synthesis of copper nanoparticles (CuNP) deposited on polyethylene terephthalate (PET) filters and antibacterial evaluation of the obtained filters against Escherichia coli and Salmonella enterica. CuNP were synthesized by a two-step method involving adsorption of [Cu(OH)4]2- ions onto a PET filter and subsequent chemical reduction by ascorbic acid without using other capping agents. The synthesized CuNP were 105 ±26 nm (mean±SD) in size and agglomerated into clusters on the PET fibres. Increasing the immersion time of the filters in [Cu(OH)4]2- solutions yielded higher amounts of deposit...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Preliminary assessment of the processing of high-acidity fatty materials using solid catalysts for the obtainment of fatty acid methyl esters
Abstract This work presents the processing of a high-acidity oil through sequential reactions of esterification using montmorillonite K10 and transesterification using zinc monoglycerolate. Since these solids had not been employed along with this approach beforehand, the objective of this work is to provide a general insight of the proposed process and demonstrate its technical feasibility. In this sense, the processing of a synthetic mixture containing soybean oil and lauric acid provided a reduction of the free fatty acid content from (40.8 ±0.1) % to (3.1±0.4) % after the esterification reaction and a fatt...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Evaluation of silica nanoparticle colloidal stability with a fiber optic quasi-elastic light scattering sensor
Abstract Colloidal silica is an important biocompatible, inert and non-toxic material for imaging, therapy, and drug delivery biomedical applications. In this context, the evaluation of colloidal suspensions and their stabilities by a Fiber Optic Quasi-Elastic Light Scattering sensor is proposed. Two different silica nanoparticles were prepared and characterized by scanning electron microscopy and X-ray diffraction, being completely amorphous, with mean diameters of 125 and 159 nm and average specific weight of 1.94 g.cm-3. The nanoparticles were dispersed in deionized water in different concentrations ranging from 0 to 2%...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

EVALUATION OF THE PHOTOCATALYTIC ACTIVITY OF SiO2@TiO2 HYBRID SPHERES IN THE DEGRADATION OF METHYLENE BLUE AND HYDROXYLATION OF BENZENE: KINETIC AND MECHANISTIC STUDY
Abstract Silica spheres coated with titania (SiO2@TiO2) were synthesized using chitosan as template. The N2 adsorption/desorption isotherms of the spheres point to meso and macroporous characteristics and the elemental mapping by EDS shows uniform distribution of Ti on the surface of the silica spheres, leading to formation of an amorphous structure (XRD). The results from the model reaction of photocatalytic degradation of methylene blue (MB) show a good stability of the spheres regarding their reuse. The tests with various additives pointed to hydroxyl radical production as the main via of MB degradation. The photocataly...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Biodiesel synthesis from waste cooking oil using a variety of waste marble as heterogeneous catalysts
Abstract The research article is based on biodiesel synthesis by the transesterification of waste cooking oil with methanol in the presence of heterogeneous catalysts prepared from different marble. Eight samples of marble were successfully converted into potential catalysts by calcination. The thermal treatment of waste marbles at 300oC-1000oC converted the metal carbonates (CaCO3) to metal oxides (CaO). The calcined marble was analyzed by chemical tests, flame atomic absorption spectroscopy (FAAS), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction studies (XRD). The presence of CaO in these catalysts...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Numerical and experimental investigation of air-water system to simulate bubble dynamics in liquid sodium pool
We report an in-house experimental technique to depict the bubble dynamics along with numerical support to establish similarity behavior between water and liquid sodium, to reduce the number of experiments in sodium systems for in-depth knowledge of bubble dynamics in the case of the fast breeder reactor. In the present work, 3-D bubble dynamics is studied in the OpenFOAM platform and the validated numerical model is used to study bubble dynamics in sodium to establish similitude between the water and sodium systems. The bubble aspect ratio of 0.9 cm diameter bubbles in the sodium system is found to be in close agreement w...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Experimental and numerical analysis of chaotic advection as an efficient approach to maximize homogeneous laminar mixing in a batch mixer
Abstract In the present work, the impacts of effective parameters on the mixing of Stokes flows in a chaotic batch mixer are numerically and experimentally studied. The batch mixer consists of a container and two circular rotors where the rotors can rotate independently. To investigate the possibility of improving the mixing, the effect of non-constant speeds, contra-rotating rotors, and varying rotor speeds are studied. The results showed that varying the rotor speed while rotating in the same direction does not significantly increase mixing. However, if the rotors rotate in opposite directions, 10-times more mixing is ac...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Study of parameters affecting the coalescence of dimethyl disulfide drops in a merox unit
This study focuses on the coalescence of dimethyl disulfide drops with the mother phase at a flat aqueous-organic interface between dimethyl disulfide and different sodium hydroxide solutions. Drop coalescence is an important part of the Merox process for regenerating the solvent. A digital high-frame rate camera was used for recording drops coalescence and duration time. Drops of dimethyl disulfide were directed in different sodium hydroxide solutions as the continuous phase. Applying the experimental design method, the influences of independent variables of drop size and physical properties on coalescence time were inves...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Simulation and experimental investigation of power consumption, gas dispersion and mass transfer coefficient in a multi-phase stirred bioreactor
Abstract Bio-oxidation leaching of refractory gold concentrate was carried out in a typical gas-liquid-solid three-phase stirred bioreactor. The bacteria, which adhered to solid particle surfaces and spread over the liquid phase, require sufficient oxygen and nutrient of carbon and nitrogen, and then the mass transfer rate should be considered. However, the mass transfer coefficient, which could be used to evaluate the mass transfer rate, was determined by gas holdup, bubble diameter and power consumption. Therefore, a three-phase Eulerian equation with k- ε turbulence model and additional models of two bubble diam...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Cantilever nanobiosensor based on the enzyme urease for detection of heavy metals
Abstract Cantilever nanobiosensors have emerged as an alternative to conventional methods of analysis to monitor heavy metals, which are being highlighted by detecting substances at the micro and nanoscale through the use of sensor layers. In the present study, a new cantilever nanobiosensor was developed functionalized with urease enzyme by self-assembled monolayers for the detection of heavy metals (lead, nickel, cadmium, zinc, cobalt, and aluminum) in water. From the calibration curves, using the statistical method of Principal Component Analysis, it was possible to observe that the nanobiosensor was highly efficient in...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

DISRUPTION OF Nannochloropsis gaditana (EUSTIGMATOPHYCEAE) RIGID CELL WALL BY NON-THERMAL PLASMA PRIOR TO LIPID EXTRACTION AND ITS EFFECT ON FATTY ACID COMPOSITION
This study assessed the effect of non-thermal plasma (NTP) on Nannochloropsis gaditana cell rupture and subsequent lipid extraction. Micrograph images showed that the surface of original N. gaditana cells appeared smooth and had no apparent holes, whereas after NTP the cells showed a non-uniform apparently fractured surface with many pores and large splits. Maximum lipid recovery from N. gaditana cells (~19%) for NTP-assisted rupture was observed at 10 min, similar to extraction after 10 min sonication (19.0%). The lipid recovery after both pretreatments (average 19.0%) was 2-fold higher than the control treatment (no pret...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

STABILIZATION STUDY OF TETRAMERIC Kluyveromyces lactis β-GALACTOSIDASE BY IMMOBILIZATION ON IMMOBEAD: THERMAL, PHYSICO-CHEMICAL, TEXTURAL AND CATALYTIC PROPERTIES
Abstract We investigated the immobilization of a tetrameric Kluyveromyces lactis β -galactosidase (EC: 3.2.1.23) (KL-Gal) on Immobead 150 using different support modification strategies. Immobead support was modified using an acid solution of H2SO4:HNO3 (3:1) (Immobead-Ac) or 5 % (v/v) glutaraldehyde (Immobead-Glu). Its unmodified form (Immobead) was also tested. Immobilization yields and efficiencies were evaluated by testing protein loads from 10 to 200 mg.g-1 support. The thermal, physico-chemical, textural and catalytic properties of the supports (modified and unmodified) and their derivatives (Immobead-KL-Gal, Im...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

ENZYMATIC PRODUCTION OF β-CYCLODEXTRIN FROM JACKFRUIT SEEDS (Artocarpus intergrifolia L.)
The objective of this study was to produce β -CD using an alternative source of starch, such as jackfruit seed (Artocarpus intergrifolia L.) bran (JSB) by a commercial CGTase. The highest productivity of β -CD (52.10 µM/h.g) was obtained from 10 g of JSB in 100 mL of citrate buffer (10 mM / pH 6.0), with 17 % (v/v) of ethanol and 1.34 U/g of CGTase, at 59 °C for 4 hours. These same conditions were applied to starches extracted from the JSB (SJSB) and ginger (SG) and also, potato starch (SP). The SJSB and SG pe rformances were similar to SP, and resulted in productivities around 2.7 times higher in relat...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Study of solubility in supercritical fluids: thermodynamic concepts and measurement methods - a review
This study reviews the fundamental knowledge of solubility in supercritical fluids and investigates the significant topics in this field, including high-pressure phase behavior, experimental measurement methods, modeling, and molecular simulation of solubility. (Source: Brazilian Journal of Chemical Engineering)
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Energy and exergetic evaluation of the multicomponent separation of petrochemical naphtha in falling film distillation columns
Abstract Multicomponent separation of synthetic petrochemical naphtha (hexane, cyclohexane, toluene and xylene) was carried out in a falling film distillation sequence with heat supply using a vapor chamber (thermosyphon). Tests were carried out by varying feed flow rate and temperatures of the feed and the vapor chamber in two ways of heat supply: isothermal and with a vapor chamber temperature profile. Regarding the distillation behavior of the multicomponent separation with the proposed falling film column, it was verified that the lower values of the studied variables and the profile temperature mode promoted the best ...
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research

Separation of sulfur-containing compounds from diesel by oxidation followed by solvent extraction in a single drop column
Abstract Oxidative desulfurization (ODS) is an attractive complementary or alternative process for the hydrodesulfurization (HDS) process due to advantages such as mild operating conditions. In the ODS process, the sulfur-containing compounds are oxidized first to polar sulfoxide and sulfone products and then these polar compounds are separated using solvent extraction or an adsorption process. In the present study, the separation of oxidized sulfur-containing compounds of diesel as a real fuel has been investigated using extraction in a single drop column. The oxidation system was hydrogen peroxide/formic acid. The select...
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research

INVESTIGATION OF THE EFFECT OF ELECTRIC FIELD ON CO2 ABSORPTION IN WATER/Fe3O4 NANOFLUID
In this study, a novel strategy for controlling the mass transfer rate in a gas-liquid system was reported and used for the industrially important system of CO2 absorption. The strategy used Fe3O4 nanoparticles in the liquid phase and also exerting an external electric field. To demonstrate this approach, a unique experimental set up was applied to form a falling liquid film, which was water, to be in contact with the gas phase, which was pure carbon dioxide. Nanofluid with concentrations less than 0.03% by volume and field intensities of 133, 200, 266 kV/m were used in this study. Experimental results showed that the exte...
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research

Synthesis, characterization, adsorption and thermodynamic studies of pure and binary co2-n2 mixtures on oxygen enriched nanostructured carbon adsorbents
Abstract Oxygen enriched porous carbons have been synthesized by a nanocasting technique using mesoporous zeolite as template and epoxy resin as precursor. Characterization results show the effect of the nanocasting technique on the development of heterogeneous surface, high basicity, and high surface area of 686.37 m2g-1, beneficial for CO2 adsorption. Pure component adsorption isotherms were correlated with Langmuir, Sips, and dual-site Langmuir (DSL) models and found that Sips and DSL isotherm models fitted well, indicating thre heterogeneous nature of the adsorbent surface. Dynamic breakthrough data for the binary syst...
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research

Quadrature algorithms for phase equilibrium of continuous mixtures
Abstract Several methods for computing the Gauss-Christoffel quadrature used for the adaptive characterization of continuous mixtures were compared as to their efficiency and robustness. Two mixtures with molar fraction distribution given by truncated gamma distributions were used. We analyzed the Product-Difference, the Golub-Welsch, the Long Quotient-Modified Difference and the Chebyshev algorithms using regular and generalized moments, when applicable. The robustness and computational efficiency of changes in the distribution variable and in the orthogonal polynomial family used to calculate the generalized moments were...
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research

Numerical simulation of coal gasification in a circulating fluidized bed gasifier
Abstract This paper presents a 3D full-loop simulation of a circulating fluidized bed gasifier. The model is validated with experimental results from the literature. The validated model is thereupon used to compare Bubbling Fluidized Bed (BFB) and Circulating Fluidized Bed (CFB) gasifiers to highlight the effect of a change in fluidization regime from bubbling to fast fluidization on hydrodynamics, temperature and gas composition. Feed temperature as well as Air/Coal (A/C) and Steam/Coal (S/C) ratios are kept constant, whereas the velocity of the feed (Air-Steam) is increased so as to get into the fast fluidization regime....
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research

Numerical study of viscoplastic flow in a t-bifurcation: identification of stagnant regions
Abstract Identification of stagnant regions of viscoplastic fluid flows in production lines and equipment is of paramount importance owing to potential material degradation and process contamination. The present work introduces an assessment strategy to identify, classify and quantify unyielded regions with the objective of optimizing the flow conditions with the purpose of minimizing stagnant regions. Flow of Carbopol ® 980 in a T-bifurcation channel is adopted to illustrate the procedure. The rheological behavior of Carbopol® 980 was simulated using the Herschel-Bulkley viscoplastic model regularized by Papanasta...
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research

A methodology to obtain analytical models that reduce the computational complexity faced in real time implementation of nmpc controllers
Abstract Model Predictive Control, MPC and NMPC, and real-time optimization, RTO and D-RTO, are known to help plant operability through the mitigation of impacts caused by external disturbances. However, the usage of these tools in industry requires overcoming some challenges, for instance: accurate models of the process, particularly in regard to nonlinearities; suitable computational time for obtaining the solution of large-scale problems and model mismatch between the RTO or D-RTO and NMPC. In this paper, we present a methodology to obtain analytical model predictions based on a Hammerstein structure to represent the pr...
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research

Sucrose crystallization: modeling and evaluation of production responses to typical process fluctuations
Abstract This work describes a phenomenological model of the two-massecuite system for sucrose crystallization, developed using EMSO software. In most Brazilian sugarcane industries, sucrose crystallization is performed using this system. This process is considered to be a fundamental step in obtaining sugar of the desired quality and accounts for a substantial fraction of the production costs. The simulation results - crystal percentage in massecuite, brix and purity of molasses, magma purity, sugar pol, crystal size distribution - were validated by comparing them with real process data of an industrial plant. The interes...
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research

Estimation of parameters and states using a bayesian particle filter for the sulfate ion adsorption process in a fixed bed column
Abstract Ensuring that industrial effluents meet quality standards to be released into water bodies is still one of the major environmental concerns. Liquid phase adsoption in fixed bed collumns is one of the most known treatments. Measurements are needed to monitor the process. However, as they are often corrupted by noise from the measuring equipment, performing an accurate analysis becomes an important challenge. The present work demonstrates the effectiveness of particle filter Sampling Importance Resampling as a fast and robust tool for monitoring a problem of sulfate ion removal. Experimental measurements were used t...
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research

Integrating real time optimization and model predictive control of a crude distillation unit
Abstract This work reports the integration of Real Time Optimization and Model Predictive Control in the multi-layer control structure of an existing Crude Distillation Unit (CDU) of an oil refinery. The MPC considers output control zones and targets for the inputs or outputs. Both the infinite horizon and the finite output horizon controllers were tested. The plant results show that the infinite horizon controller tends to perform similarly or better then the finite horizon MPC when the CDU system needs to operate at quite different conditions. Although the dynamic layer based on the infinite horizon controller is nominal...
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research

Re-esterification of macauba acid oil using glycerol for acidity reduction and biodiesel production
Abstract Biodiesel production using acid oils is an important alternative for biofuel cost reduction. However, it is a huge challenge for homogeneous transesterification, the main industrial route commonly used. This paper presents macauba oil with high acidity, 43.90 w/w%, as a potential raw material for biodiesel production. The acidity was reduced to 0.8 w/w% after re-esterification (80 min) with glycerol at high temperature (235 °C), without catalysts. Zinc (powder and coating) and NbOPO4 were also tested as catalysts in comparison with the reaction without a catalyst. Reactions catalyzed by metallic Zn produced a ...
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research

Synthesis, characterization and evaluation of the heterogeneous basic catalyst dapts-mcm-41 in the interesterification reaction of palm oil and palm kernel oil blends
Abstract In recent years, the replacement of homogeneous catalysts by heterogeneous catalysts has been investigated as a sustainable alternative technology to obtain different products. In this context, this study investigated the activity of the heterogeneous catalyst DAPTS-MCM-41, obtained from the reaction between the MCM-41 molecular sieve and an organic base 3-ethylenediamine (trimethoxy) propyl silane (DAPTS) in the interesterification reaction of palm oil and palm kernel oil blends. The catalyst was characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD) and textural analysis (ASAP). The interesterifi...
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research

CATALYTIC OXIDATION OF ISOPROPYL ALCOHOL OVER PLATINUM BASED CATALYST: A STUDY OF THE EFFECT OF METHYL CELLULOSE ON Pt PARTICLES DISPERSION OVER MULLITE
This study showed that platinum exhibits better dispersion on alumina sites than silica sites. This can be due to a strong interaction between platinum and alumina, leading to a higher dispersion of platinum species. Furthermore, the addition of MC enhanced the Pt dispersion over the mullite, leading to an improvement in the catalytic performance. (Source: Brazilian Journal of Chemical Engineering)
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research

GRAPHENE OXIDE AND A GO/ZnO NANOCOMPOSITE AS CATALYSTS FOR EPOXY RING-OPENING OF EPOXIDIZED SOYBEAN FATTY ACIDS METHYL ESTERS
Abstract In this work, the grapheme oxide (GO) and GO/ZnO nanocomposite were successfully obtained from the oxidation of graphite and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). In the GO/ZnO nanocomposite, the GO sheets were coated with aggregated ZnO nanoneedles with ca. 20 nm of diameter. The obtained materials were used as heterogeneous catalysts for acetylation of Soybean Fatty Acids Methyl Esters (FAME), promoting the epoxy ring-opening using acetic anhydride. The epoxy ring was almost completely opened in ...
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research

Determination of reactivity and thermodynamic analysis of nickel-based oxygen carriers for chemical-looping combustion
Abstract This work aimed to study nickel-based oxygen carriers (OC) for Chemical Looping Combustion (CLC) using H2 and CH4 as fuel. The reactivity and reaction kinetics of the OC were investigated, applying the shrinking core, nucleation and diffusion models in three dimensions, as well as whether the OC is thermodynamically favorable for the reaction. The results showed that the OC achieved high conversion for both fuels, proving to be quite reactive, while the fuel gas concentration and the temperature have a strong effect on the solids conversion. For the H2 combustion, the reaction rate can be described well by the shr...
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research

An investigation of the heat transfer performance of dual improved intermig impellers in a stirred tank with an inner heating coil
Abstract The heat transfer process in a stirred tank of diameter T=0.5m equipped with dual-layer improved Intermig impellers and helical coils was investigated by experiment and numerical simulation methods. The temperature field, the temperature boundary layer lateral to the coil and the heat transfer coefficient were measured at different rotational speeds. The standard k- ε turbulence model and multiple reference frames combined with a sliding mesh method were adopted in the numerical simulation. The results show that the temperature errors between numerical simulation and experimental measurement were within 2K...
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research

Water holding capacity and heat transfer aspects of a mixture of sugar cane bagasse and wheat bran in a partially filled rotating drum
Abstract Maximum water holding capacity of a mixture of sugarcane bagasse and wheat bran was determined in static conditions and in a drum rotated at 1 rpm. The variables filling degree, water flow rate, volume of added water and number of sprinklers were tested to control the moisture content of the solid and the number of rotations to achieve homogeneous moisture content. None of the selected variables was significant, giving the apparatus high flexibility to control moisture content. For the heat transfer experiments, the tested variables were introduction of air through an inner tube amidst the particles, water sprinkl...
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research

Modeling and simulation of a vacuum membrane distillation plant coupled with solar energy and using helical hollow fibers
In conclusion, these results are important in the membrane module design for practical membrane distillation applications. (Source: Brazilian Journal of Chemical Engineering)
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research

Influence of hydraulic retention time on hydrogen production by treating cheese whey wastewater in anaerobic fluidized bed bioreactor - an approach for developing countries
This study assessed the effect of hydraulic retention time (HRT) on biohydrogen production by dark fermentation using an anaerobic fluidized bed reactor fed with cheese whey synthetic wastewater. The reactor of 1.2 L was operated with an approximate carbohydrate concentration of 2800 mg L-1, and HRTs of 6, 4, 2, 1 and 0.5 h. Acetic and butyric acids were the main metabolites produced in the reactor. The hydrogen production increased from 0.039 to 1.43 L-H2 h-1 L-1-reactor as the HRT decreased from 6 to 0.5 h. The best hydrogen yield (HY) (2.73 mol-H2 mol-carbohydrate-1) and carbohydrate consumption (81.02%) were achieved a...
Source: Brazilian Journal of Chemical Engineering - December 10, 2019 Category: Chemistry Source Type: research