Brazilian Journal of Chemical Engineering 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.

Comparative study for adsorption of hydrogen-methane mixtures on activated carbon and 5a molecular sieve
Abstract Equilibrium adsorption isotherms were obtained experimentally by a static method for a binary component hydrogen-methane mixture on activated carbon and 5A molecular sieve adsorbents. The temperature range 303-333 K and pressure range 0 - 4 MPa were examined. Methods for predicting gas-mixture equilibrium adsorption data from the pure-component isotherms were evaluated. Extended Langmuir model correlated the adsorption of binary mixtures fairly well. In all cases mutual interference was found, that is, the amount of a given gas adsorbed at a given partial pressure was always less in the mixture than it would have ...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Extraction of rice bran oil using supercritical co2 combined with ultrasound
Abstract Rice bran oil (RBO) contains oryzanol and tocopherols. Its recovery was performed using conventional techniques with toxic solvents that leave residues in the final product. Supercritical fluid extraction (SFE) has been used, obtaining high global yields without residual solvent. This work proposes to use ultrasound to enhance the kinetics of the RBO extraction using supercritical CO2. The factors considered were ultrasound power (160 to 320 W) and sonication time (40 to 120 min), at 40 ºC and 25 MPa. The best condition (160 W / 40 min) resulted in a 12.65 wt% extraction yield. When ultrasound was not used, the g...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Operational design and improvement of conventional batch distillation and middle-vessel batch distillation
Abstract Conventional batch distillation and middle-vessel batch distillation were studied for the separation of the ternary system of cyclohexane/n-heptane/toluene, which has low relative volatilities. The modified variable and constant reflux operations were applied in the conventional batch distillation. Two control structures were used: one of which was referred to as the composition control structure with a modified level-set point, and the other was referred to as the flowrate-limiting control structure. Thus, the middle-vessel batch distillation was able to simultaneously separate the components of the ternary mixtu...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Optimization of kinetic lumping model parameters to improve products quality in the hydrocracking process
In this study a typical continuous lumping model with five parameters has been used for kinetic modeling of thermal and catalytic hydrocracking. Model parameters have been optimized according to experimental product distributions using a particle swarm optimization (PSO) algorithm. Experimental data from the hydrocracker setup have been employed to validate the proposed model. In this setup hydrogen and vacuum gasoil feed were introduced from the top of a vertical reactor and, after passing through a catalyst bed, the liquid and gas products were separated and analyzed. Temperature of the reactor was adjusted in the range ...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Soft sensor models for a fractionation reformate plant using small and bootstrapped data sets
Abstract In refinery plants key process variables, like contents of process stream and various fuel properties, need to be continuously monitored using adequate on-line measuring devices. Such measuring devices are often unavailable or malfunction and, hence, laboratory assays which are irregular and time consuming and therefore not suitable for process control are inevitable alternatives. This research shows a comparison of different soft sensor models developed from a small industrial data set with soft sensor models developed from data generated by a bootstrap resampling method. Soft sensors were developed applying mult...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Predicting the penetration and navigating the motion of a liquid drop in a layered porous medium: viscous fingering vs. capillary fingering
Abstract In this paper, penetration of a liquid drop in a layered porous medium as well as its motion navigation was investigated using the lattice Boltzmann method (LBM). The porous medium was generated by locating square obstacles randomly in the each layer which would cause the layered porosity in the domain. Two regimes of penetration; (a) capillary fingering regime and (b) viscous fingering regime were used for this study. The relationship between the porosity and the penetration rate was studied. The effect of porous surface type (i.e., hydrophobicity or hydrophilicity) on the penetration rate and penetration pattern...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Fabrication of spinel coating on hp40 alloy and its inhibition effect on catalytic coking during thermal cracking of light naphtha
Abstract A novel two-step process of Cr-Mn pack cementation and thermal oxidation was applied to fabricate a MnCr2O4 spinel coating on HP 40 alloy. The Cr-Mn diffusion layer formed after the Cr-Mn pack cementation process is lacking in Fe and Ni. A dense and uniform coating formed on the alloy following thermal oxidation. The coating is mainly composed of MnCr2O4 spinel phase, while the outer surface of the coating is completely MnCr2O4 spinel. The coating exhibits a favorable thickness of about 7 µm according to SEM and EDS maps of its cross-section. The MnCr2O4 spinel coating significantly affects the coking mechanism a...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Preparation of micron-sized droplets and their hydrodynamic behavior in quiescent water
Abstract To study the hydrodynamics of rising droplets (especially less than 1 mm) in quiescent water, a microfluidic device with co-flowing configuration was integrated to prepare micron-sized droplets. Soybean oil and toluene droplets of size from 100 to 600 µm were obtained by five co-flowing devices with different capillary sizes. It is found that the capillary device with smaller tip size produces smaller droplets and, for a given device, the droplet size decreases with the increase of continuous phase flow rate. Alternatively, the increase of dispe rsed phase flow rate has little influence on the droplet size. To pr...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Production of castor oil maleate using di-tert-butyl peroxide as free radical catalyst
Abstract Castor oil maleate is used in healthcare products, synthetic lubricants, drying oils, water-soluble paints and as a monomer in several polymers. This compound is formed by direct reaction between castor oil and maleic anhydride, which can be accelerated using free radical catalysts. In this work, the influence of processing temperature and the concentration of di-tert-butyl peroxide (DTBP) in the production of castor oil maleate was studied applying response surface methodology. The results showed that the use of the radical initiator increased the rate of reaction, leading to a shorter reaction time and higher pr...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Development of antioxidant poly(thioether-ester) nanoparticles
Abstract Poly(Thioether-Ester) nanoparticles synthetized via thiol-ene polymerization from a renewable castor oil monomer are produced by miniemulsion polymerization and emulsification/evaporation of pre-formed polymer. Its antioxidant activity, probably due to the oxidation of sulfide groups, is confirmed by 2,2-diphenyl-1-picryl hydrazyl (DPPH) free radical-scavenging and β -carotene/linoleic acid assays, with an amount of polymer required to reduce the initial concentration of DPPH · radicals by 50% of ~195 µg.ml-1 promoting hydrogen or electron exchange and the capability to prevent lipid peroxidation of ~55%. The r...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Theoretical models for rates of heterogeneous reactions during combustion and gasification of liquid fuels in fluidized beds
Abstract Two mathematical models to allow computations of chemical species production or consumption rates by heterogeneous reactions taking place during combustion and gasification of liquid fuels sprayed on or injected into fluidized beds of solid particles are proposed. The possibilities envisaged here are called: the CIP (Coated Inert Particles) and the CSP (Coke Shell Particle) models. The former assumes that the injected liquid fuel immediately coats the fluidized inert particles in the bed and then goes through pyrolysis, combustion and gasification reactions. The latter presumes that the liquid fuel drops go throug...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Hydrotalcite-impregnated copper and chromium-doped copper as novel and efficient catalysts for vapor-phase hydrogenation of furfural: effect of clay pretreatment
Abstract A series of novel catalysts based on immobilization of copper and chromium-doped copper on calcined and uncalcined hydrotalcite support have been developed and used for promoting vapor-phase hydrogenation of furfural. The results indicated that a pre-calcination of the support has a negative role in changing the structural features and catalytic activity of the final catalysts. Moreover, the presence of the Cr promoter can improve the catalyst performance. The best performance (furfuryl alcohol selectivity of 94% and furfural conversion of 89%) was obtained over the Cr-doped copper catalyst supported on as-synthes...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Selective chlorination of glycerol to 3-chloro-1,2-propanediol catalyzed by brØnsted acidic ionic liquids
Abstract Br ønsted acidic ionic liquids composed of 1-butyl-3-methylimidazolium, triethylbutylammonium, and 1-butylpyridinium cation counterparts and HSO4 ‾ and H2PO4 ‾ anion counterparts were used as the catalysts for the selective chlorination of glycerol with hydrogen chloride to 3-chloro-1,2-propandiol. From the perspective of the glycerol conversion and product yields, the catalytic activities of the ionic liquids containing HSO4 ‾ were higher than the ionic liquids containing H2PO4 ‾ . As compared with the carboxylic acid catalysts, Br ønsted acidic ionic liquids favored the catalytic chlorination of gly...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Cellulase immobilization on poly(methyl methacrylate) nanoparticles by miniemulsion polymerization
Abstract Cellulases are efficient enzymes for the conversion of cellulose into glucose. Their use in immobilized form enables them to be reused in successive cycles in many biotechnological processes. Unlike conventional methods of immobilization by covalent bonding, in miniemulsion polymerization the immobilization of enzyme and the synthesis of polymer nanoparticles (support) occur simultaneously. Based on these aspects, the immobilization of cellulose on poly(methyl methacrylate) (PMMA) nanoparticles by miniemulsion polymerization was studied. The surfactant type (non-ionic and ionic) and latex pH showed great influence...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Hydrodynamic characteristics of a structured bed reactor subjected to recirculation and intermittent aeration (sbrria)
ABSTRACT This work aimed at evaluating the effect of recirculation ratio on the degree of mixing in the flow of a structured bed reactor. Stimulus-response assays were carried out with hydraulic retention times of 6 h and 12 h, subjected to recirculation ratios of 0, 1, 2, 3, and 4. The assays were undertaken with dextran blue as a tracer and without aeration. The results fitted a compartment model, allowing the determination of the mixed-flow and plug-flow volumes inside the reactor. The model application showed that recirculation ratios between 1 and 3 do not increase the mixed-flow volume of the reactor. Higher mixed-fl...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research