Brazilian Journal of Chemical Engineering 
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This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.N-acetylcysteine micronization by the seds technique using supercritical co2
ABSTRACT N-Acetylcysteine (NAC) is a thiol (-SH) with a strong antioxidant activity. This compound has demonstrated positive effects on chronic kidney disease, cancer, pulmonary insufficiency and other diseases. The aim of this work was to investigate the application of the Solution Enhanced Dispersion by Supercritical Fluids (SEDS) technique in the micronization of NAC using a 23 Central Composite Design (CCD) with 3 central points, as well as to assess the influence of active compound concentration, temperature and pressure on the particle size produced. The average size of the drug before SEDS processing was verified to...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research
Chemical potentials of hard-core molecules by a stepwise insertion method
ABSTRACT A molecular simulation algorithm was implemented to calculate chemical potentials of hard-core molecular systems at high densities. The method is based on the Widom particle insertion method and the step-function character of free energy variations. The algorithm was evaluated for hard-sphere mixtures at infinite dilution approximation by varying the solute/solvent diameter ratio, for systems with reduced densities from 0.1 to 0.8. The proposed methodology was verified by comparing simulations of trimers diluted in spheres and of single-component dimer systems with results from the literature. Then, the method was...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research
Erratum
Abstract Gas hydrates are crystalline compounds, solid structures where water traps small guest molecules, typically light gases, in cages formed by hydrogen bonds. They are notorious for causing problems in oil and gas production, transportation and processing. Gas hydrates may form at pressures and temperatures commonly found in natural gas and oil production pipelines, thus causing partial or complete pipe blockages. In order to inhibit hydrate formation, chemicals such as alcohols (e.g., ethanol, methanol, mono-ethylene glycol) and salts (sodium, magnesium or potassium chloride) are injected into the produced stream. T...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research
An Examination of the Prediction of Hydrate Formation Conditions in the Presence of Thermodynamic Inhibitors
Abstract Gas hydrates are crystalline compounds, solid structures where water traps small guest molecules, typically light gases, in cages formed by hydrogen bonds. They are notorious for causing problems in oil and gas production, transportation and processing. Gas hydrates may form at pressures and temperatures commonly found in natural gas and oil production pipelines, thus causing partial or complete pipe blockages. In order to inhibit hydrate formation, chemicals such as alcohols (e.g., ethanol, methanol, mono-ethylene glycol) and salts (sodium, magnesium or potassium chloride) are injected into the produced stream. T...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research
Competitive Adsorption of Dye Species onto Biomass Nanoporous Carbon in Single and Bicomponent Systems
ABSTRACT We first present a cost-effective approach to simultaneously dispose of rutaceae plant waste (the discarded peels of orange, finger citron, pomelo and lemon) to yield biomass nanoporous carbons (BNCs). The adsorption of orange II (OII) and acid chrome blue K (ACBK) from aqueous solutions in single and binary dye systems by four types of BNCs were studied in a batch adsorption system. The adsorption studies include both equilibrium adsorption isotherms and kinetics. Four adsorption models for predicting the multicomponent equilibrium sorption isotherms have been compared in order to determine which one is the best ...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research
Mathematical modeling of the batch adsorption of proteins on new restricted access media with poly(ethylene glycol) as a semi-permeable barrier using compact finite differences
Abstract In this work we describe a mathematical analysis of the batch adsorption process of several proteins using a new restricted access medium consisting of agarose beads grafted with poly(ethylene glycol) (PEG) as a semi-permeable barrier and immobilized metal ions or ion exchange groups as binding sites. The model was fitted to experimental data, allowing the estimation of the adsorption rate constant and the effective diffusivity for each protein. The model was solved using compact finite differences in a MATLAB ® platform. According to the results, the presence of grafted PEG reduces the adsorption of all proteins...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research
Fractionation of Apis mellifera venom by means of ultrafiltration: removal of phospholipase A 2
Abstract The fractionation of apitoxin (bee venom) by means of a commercial 10 kDa ultrafiltration membrane was investigated aiming at the removal of phospholipase A2, the main allergenic substance. The feed content was varied from 1 to 50 g apitoxin/L, in deionized water, and caused changes in membrane flux and rejection, due to concentration polarization. The increase in pressure difference and stirring rate improved the flux through the membrane. The best result was achieved for 1 g apitoxin/L in feed stream, with a pressure difference of 220 kPa, and 750 rpm, with a permeate flux of 103 kg/m2h. The use of ultrafiltrati...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research
Harmonious interaction of incorporating CNTs and zeolitic imidazole frameworks into polysulfone to prepare high performance MMMs for CO 2 separation from humidified post combustion gases
Abstract Multi-walled carbon nanotubes (CNTs) and zeolitic imidazole frameworks (ZIF-301) were synergistically incorporated into glassy polysulfone (PSF) to prepare mixed-matrix membranes (MMMs) to separate CO2 from post combustion flue gas. The flexible MMMs rendering consistent distribution and improved adhesion of nanofillers with the polymer matrix were hydrothermally stable under wet conditions. Gas sorption analysis along with dry and wet gas permeation experiments showed that both CO2 permeability and CO2/N2 selectivity of MMMs were improved owing to the synergistic effect of nanofillers. The MMM filled with 18 wt %...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research
An integrated optimization and simulation model for refinery planning including external loads and product evaluation
This study describes an integrated approach involving nonlinear optimization and simulation of refinery units in order to obtain a production planning for a given refinery that maximizes profit. The problem is modeled through the LINGO 16.0 software interface and is solved using LINGO ’ s Global Solver on an Intel i5-2410M processor (8 GB RAM). A case study pertaining to the Refinaria de Paul ínia (REPLAN) is proposed, and external loads, product adding, and product pricing is studied, achieving a global optimum solution for the blending in less than a second in every case.The small computational time assures the model ...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research
Lithium containing MgAl mixed oxides obtained from sol-gel hydrotalcite for transesterification
Abstract The innumerous advantages of heterogeneous catalysts employed in biodiesel production have stimulated the search for a solid catalyst capable of replacing the industrially used homogeneous catalysts. This paper investigates the effect of the sol-gel method in the catalytic activity and stability of Li-MgAl mixed oxides prepared by the “ in situ ” lithium addition to a MgAl hydrotalcite. The analyses based on N2 physisorption, thermogravimetric analysis, X-ray diffractometry, scanning electron microscopy and temperature-programmed desorption of CO2 were carried out to elucidate the properties of the catalysts....
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research
ZnO nanoparticle fabrication starting from ultra-high (1:2) PVOH/ZnAc proportion electrospun nanowire mats
Abstract: The high versatility of nanostructured ZnO has drawn considerable attention from the scientific community since the second half of the two thousand decade. Within this timeframe, electrospinning became one of the simplest ways to produce nanostructured ZnO. In this work, we present the production and characterization of ZnO nanoparticles obtained from electrospun fiber mats using the highest (1:2) PVOH/ZnAc proportion reported so far. The thermally annealed samples were characterized using , X-Ray Diffraction (XRD), High Resolution Scanning Electron Microscopy (HRSEM), Energy Dispersive X-Ray analysis (EDS) and C...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research
Modification of palm oil crystallization by phytosterol addition as a tool for structuring a low saturated lipid blend
Abstract Fat structural modifications promoted by phytosterol addition ( a hypocholesterolemic component ( to palm oil and a mixture of palm oil and canola oilwere evaluated in order to develop fats with reduced saturated fatty acids. Palm oil added with free or esterified phytosterols was investigated in terms of triacylglycerol composition, microstructure, solid fat content, and crystallization behavior before and after chemical interesterification. The addition of 10% of free phytosterols to samples before interesterification built up a denser crystal fat network structure. After interesterification, the free phytostero...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research
Effect of Lime Addition to CaSO 4 Oxygen Carrier in Chemical Looping Combustion
In this study, CLC experiments of methane using CaSO4 oxygen carrier with lime addition were carried out in a batched fluidized bed reactor, where the sample was exposed to alternate oxidizing and reducing conditions. The influences of temperature, calcium-to-sulphur ratio and lime particle size on the conversion of CaSO4 and sulfur capture were investigated and a suitable operation condition was determined. Under the optimal operation condition, a multi-cycle test was performed to evaluate the cyclic redox behavior of the lime-promoted CaSO4 sample. X-ray diffraction and a field emission scanning electron microscope were ...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research
Ce/kaolin clay as an active catalyst for fatty acid methyl esters production from cottonseed oil in a new integrated apparatus
Abstract An efficient solid acid catalyst (Ce/Kaolin clay) was prepared and investigated for transesterification of cottonseed oil to fatty acid methyl esters (FAME). The catalysts were characterized by XRD, BET, and NH3-TPD measurements. A new integrated apparatus for extraction and transesterification of cottonseed oil was developed. The effects of cerium loading, catalyst calcination temperature, methanol flow rate, reaction temperature, reaction time, and catalyst amount were also investigated. The results indicated that the Ce/Kaolin clay showed high catalytic activity under the calcination temperature of 700 oC and c...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research
Optimization of the performance of a microbial fuel cell using the ratio electrode-surface area / anode-compartment volume
Abstract This paper focus on the determination of the influence of the electrode-surface area / anode-compartment volume ratio (ESAVR) on the performance of microbial fuel cells (MFC), both in terms of the generation of electricity and the removal of organic matter from waste. Real wastewater coming from a winery factory was used and five ESAVRs were tested in separate MFCs, ranging from 0.15 to 0.75cm2cm-3. Results demonstrate that the electricity generation increases by decreasing the anode-compartment volume. Thus, by increasing ESAVR, maximum current density increased from 583 to 2416 mA m-2. However, the COD removal w...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research
