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.A TVD scheme for 3d unstructured grids applied to compositional reservoir simulation
Abstract In reducing the grid orientation effect for the numerical solution of partial differential equations, interpolation functions play an important role when the advective transport of the governing equations is considered. This is due to the fact that, in general, the unknowns are evaluated in the vertices of the elements and such properties must be extrapolated to inner parts of the elements. First-order schemes, such as upwind, are the easiest methods to use for performing the extrapolation of the properties. However, such methods introduce a large amount of numerical diffusion in the solution. A few higher-order i...
Source: Brazilian Journal of Chemical Engineering - February 15, 2018 Category: Chemistry Source Type: research
Discharge of Non-Reactive Fluids from Vessels
Abstract This paper presents simulations of discharges from pressure vessels that consistently account for non-ideal fluid behavior in all the required thermodynamic properties and individually considers all the chemical components present. The underlying assumption is that phase equilibrium occurs instantaneously inside the vessel and, thus, the dynamics of the fluid in the vessel comprises a sequence of equilibrium states. The formulation leads to a system of differential-algebraic equations in which the component mass balances and the energy balance are ordinary differential equations. The algebraic equations account fo...
Source: Brazilian Journal of Chemical Engineering - February 15, 2018 Category: Chemistry Source Type: research
Simulation of species concentration distribution in reactive flows with unsteady boundary conditions
Abstract The determination of species concentration profiles in reactive flows with variable inlets is a problem of practical interest to many fields such as in flow reactor transient operation and in cyclic degradable pollutants disposals in watercourses. In these cases, the inflow condition often consists of a time-dependent function, which may imply unsteady outflows, not always well represented by the usual boundary conditions (BC) used so far. A new approach, using an outlet condition in the form of a material derivative, termed Material Derivative Boundary Condition (MDBC), is introduced and a numerical model to solv...
Source: Brazilian Journal of Chemical Engineering - February 15, 2018 Category: Chemistry Source Type: research
Comparing a Dynamic Fed-Batch and a Continuous Steady-State Simulation of Ethanol Fermentation in a Distillery to a Stoichiometric Conversion Simulation
In this study it was found that the conversion rates of sugar for the fermentation systems analyzedwere predictable from information on the composition of the juice stream. Those rates were used in the stoichiometric model, which accurately reproduced the results from both the fed-batch and the continuous fermenter system. (Source: Brazilian Journal of Chemical Engineering)
Source: Brazilian Journal of Chemical Engineering - February 15, 2018 Category: Chemistry Source Type: research
A novel transition identification mechanism for the diesel blending and distribution scheduling problem using the discrete time representation with two time-scales granularity
ABSTRACT Transitions between tasks arise in many different scheduling problems. Sometimes transitions are undesired because they incur costs; sometimes they are undesired because they require setup time, and sometimes both. In one way or the other, frequently, transitions need to be identified and penalized in order for their frequency to be minimized. The present work is concerned with the study of alternative optimization formulations to address transitions with the blending and distribution scheduling of oil derivatives. Our study starts by revisiting a model proposed in the literature that was built considering a very ...
Source: Brazilian Journal of Chemical Engineering - February 15, 2018 Category: Chemistry Source Type: research
AnaBioPlus: a new package for parameter estimation and simulation of bioprocesses
Abstract A very important step in the study of bioprocesses is the modeling and simulation of bioreactors. This paper presents the AnaBioPlus software package, which was developed for teaching and research purposes concerning the analysis of bioreactors. The package consists of two programs: OptimusFerm and SimulaFerm. OptimusFerm allows the analysis of experimental batch cultivation data sets in order to estimate parameters of kinetic models by means of a differential evolution method. SimulaFerm performs simulations obtaining values of cell growth, product formation, and limiting substrate consumption for batch, fed-batc...
Source: Brazilian Journal of Chemical Engineering - February 15, 2018 Category: Chemistry Source Type: research
Preparation of Zinc Oxide-Nanoclay Hybrids by Alkaline Ion Exchange Method
Abstract ZnO/nanoclay hybrids are synthesized by a single-step solid-state reaction using ZnCl2 as a reagent. These hybrids were prepared by a simple alkaline ion exchange method, without using any surfactant or chelating agents. By adjusting the reagent ’ s immersion time in molten salt, production of pure ZnO/nanoclay hybrids was achieved. Synthesized hybrids were characterized by UV-vis diffuse reflectance spectroscopy, XRD, XRF and SEM. SEM confirmed increased nanoclay porosity. The XRD pattern of the ZnO/nanoclay indicated small changes in the intensity and position of the interlayer spacing of montmorillonite. Anti...
Source: Brazilian Journal of Chemical Engineering - February 15, 2018 Category: Chemistry Source Type: research
Influence of the anodizing process variables on the acidic properties of anodic alumina films
Abstract In the present work, the effect of the different variables involved in the process of aluminum anodizing on the total surface acidity of the samples obtained was studied. Aluminum foils were treated by the electro-chemical process of anodic anodizing within the following variable ranges: concentration = 1.5-2.5 M; temperature = 303-323 K; voltage = 10-20 V; time = 30-90 min. The total acidity of the samples was characterized by two different methods: acid-base titration using Hammett indicators and potentiometric titration. The results showed that anodizing time, temperature and concentration were the main variabl...
Source: Brazilian Journal of Chemical Engineering - February 15, 2018 Category: Chemistry Source Type: research
Effect of dissolution kinetics on flotation response of calcite with oleate
Abstract Phosphate flotation performance can be influenced by the dissolution kinetics of the minerals that compose the ore. The purpose of this work was to investigate the effect of dissolution kinetics on flotation response with oleate (collector) of calcites from different origins and genesis. The calcite samples were first purified and characterized by x-ray Fluorescence (XRF) and the Rietveld method applied to x-ray Diffractometry data (RXD). Experiments of calcite dissolution and microflotationwere performed at pH 8 and pH 10.The pH effect on the calcite dissolution and flotation indicates the possible influence of t...
Source: Brazilian Journal of Chemical Engineering - February 15, 2018 Category: Chemistry Source Type: research
An entirely renewable biofuel production from used palm oil with supercritical ethanol at low molar ratio
Abstract The biofuel production from used palm oil (UPO) using supercritical ethanol (SCE) at low molar ratio was investigated in order to produce an entirely renewable fuel. The effects of the reaction time and ethanol to oil molar ratio were considered from 0.5 to 10 min and 6:1 to 18:1, respectively. The optimal parameters were 10 min and a 12:1 molar ratio, representing a remarkable reduction from 42:1 for the conventional SCE process. Because of the high operating temperature, the triglycerides conversion rate reached 99%, and the glycerides content met the international speci fi cation for biodiesel. However, an est...
Source: Brazilian Journal of Chemical Engineering - February 15, 2018 Category: Chemistry Source Type: research
Convective recirculation effect on the selective non-catalytic reduction behavior in an industrial furnace
Abstract Selective non-catalytic reduction (SNCR) has become an important technique for reducing NOx emissions in industrial furnaces. The occurrence of convective recirculation can cause significant changes in SNCR performance. This paper presents the results of a study performed by Computational Fluid Dynamics (CFD) considering: (i) changes of initial NOX; (ii) injection plan and (iii) NH3/NO molar ratio. The simulations have demonstrated that the convective recirculation (resultant from different injection plans and high temperature gradients) of flue gas assumes a role of vital importance for performance analysis of ex...
Source: Brazilian Journal of Chemical Engineering - February 15, 2018 Category: Chemistry Source Type: research
Investigation of hydrodynamics and heat transfer in pseudo 2D spouted beds with and without draft plates
Abstract In the present study, hydrodynamics and gas to particle heat transfer in pseudo two dimensional spouted beds (2DSB) with and without draft plates were investigated using the Eulerian-Eulerian approach. The main objective of the study was to provide an understanding of effects of the presence of draft plates on the hydrodynamics and heat transfer behavior of solid particles in the spouted beds. To validate the model, the predicted mean particle vertical velocity at the bed axis, the lateral profiles of vertical particle velocity at different bed heights for both systems, and the particle velocity vector fields in t...
Source: Brazilian Journal of Chemical Engineering - February 15, 2018 Category: Chemistry Source Type: research
The effect of temperature on the efficiency of aerobic biodegradation of sugar beet distillery stillage: Removal of pollution load and biogens
Abstract Beet stillage is a high-strength effluent from the production of ethanol from sugar beet. A large annual volume of sugar beet stillage requires finding new effective ways for its utilization. The aim of the study was to investigate the effect of temperature on the efficiency of aerobic biodegradation of beet stillage. Biodegradation was carried out for 168 hours in a stirred-tank reactor with a working volume of 5 L at 27 °C, 36°C, 45°C, 54°C and 63°C. All experiments were performed at uncontrolled pH, aeration of 1.0 vvm and of 900 rpm. The effectiveness of biodegradation was determined by the extent of remo...
Source: Brazilian Journal of Chemical Engineering - February 15, 2018 Category: Chemistry Source Type: research
Dairy manure wastewater in serial UASB reactors for energy recovery and potential effluent reuse
Abstract This manuscript addresses the use of dairy manure wastewater (DMW) as a substrate for methane production in a high rate system - two serial UASB reactors - and the characterization of the effluent in the different phases of the treatment. Two experimental conditions were applied. In the first, the organic load rate (OLR) was 6.2 gCODtotal L-1 d-1 and the hydraulic retention time (HRT) was 12 days, whereas in experiment 2 they were 14.2 gCODtotal L-1 d-1 and 7.5 days, respectively. The reactors showed a high capacity of removal of COD and solids, i.e., above 71%, which led to bioenergy productivities of 0.55 and 0....
Source: Brazilian Journal of Chemical Engineering - February 15, 2018 Category: Chemistry Source Type: research
Nutrient Biological Removal in an Up-flow Sludge Bed Reactor under Intermittent Aeration using Glycerol as the Sole Carbon Source
Abstract This work evaluated the feasibility of glycerol as the sole carbon source for nutrient biological removal in an intermittently aerated bioreactor. The reactor operation was divided into two phases: the first one aimed only at removing nitrogen; and the second one aimed at removing nitrogen and phosphorus. In the first operational phase, three C/N (Carbon / Nitrogen) ratios were tested: 1.2, 1.5 and 1.8. For a C/N ratio of 1.8, higher denitrification efficiency was achieved (91 ± 8%). During the second phase, the reactor was subjected to periods of aeration and non-aeration of 2 h and 4 h, respectively, for a C/P ...
Source: Brazilian Journal of Chemical Engineering - February 15, 2018 Category: Chemistry Source Type: research
