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.

Microbioreactors as engineering tools for bioprocess development
ABSTRACT Within the engineering and development of industrial bioprocesses, microbioreactors are microfluidic tools able to provide high-throughput screening tests in a fast and cheap manner by using small amounts of reagents. In addition, such tools are versatile and may allow a better controllability of parameters when compared to conventional bench-scale reactors. Consequentially, this technology has been gaining attention from the scientific community over the past years. In such scenario, this work provides a review study of the microbioreactor technology, outlining the origin, main concepts and principles of such tec...
Source: Brazilian Journal of Chemical Engineering - March 28, 2019 Category: Chemistry Source Type: research

Thermodynamic properties and pitzer parameter determination for orthophosphoric acid from freezing point and isopiestic measurement data
Abstract The freezing depression points of aqueous phosphoric acid have been determined using a method based on measurement of solution conductivity. The osmotic coefficient for freezing point lowering was calculated by the condition of solid-liquid equilibrium and by the equation proposed by Bjerrum (1918). A calculation method is presented in this study to evaluate the ion interaction parameters for the Pitzer model from freezing point and isopiestic molalities of aqueous phosphoric acid solution. The model of Chen, Bromely and the Three-Characteristic Parameter Correlation (TCPC) are also used to model this system. The ...
Source: Brazilian Journal of Chemical Engineering - January 21, 2019 Category: Chemistry Source Type: research

Study of alpha-amylase obtained by solid state fermentation of cassava residue in aqueous two-phase systems
Abstract The α -amylase enzyme was produced by solid state fermentation (SSF) and its partition behavior in Aqueous Two-Phase Systems (ATPS) was determined using systems consisting of polyethylene glycol (PEG) and potassium phosphate buffer. To determine the best conditions for α -amylase production, a central composite design was constructed for two independent variables: fermentation time and moisture content, and for the partition study, a face-centered central composite design (CCF) with four independent variables: PEG molecular weight, pH, temperature and partition time. It was indicated that the best enzyme product...
Source: Brazilian Journal of Chemical Engineering - January 21, 2019 Category: Chemistry Source Type: research

Fractionation process of essential oils by batch distillation
Abstract The greatest obstacle in simulating processes involving essential oils is the small number of thermo-physical properties and experimental data available in the literature. In this work, thermodynamic models are investigated in order to predict such properties, which are requisites for the modelling and simulation of the Eucalyptus essential oil batch distillation processes. A group contribution method was used to predict the vapor pressure (CSGC-PVR) when experimental data were unavailable. Regarding the activity coefficients, a fully predictive model based on quantum calculations (COSMO-SAC) is used. Moreover, th...
Source: Brazilian Journal of Chemical Engineering - January 21, 2019 Category: Chemistry Source Type: research

C-phycocyanin purification: multiple processes for different applications
Abstract C-phycocyanin is a potential nutraceutical/pharmaceutical candidate with functionalities that are better documented than those of health foods in general. Studies have demonstrated that C-phycocyanin has antioxidant and antitumor properties and potential activities against other diseases. However, its large-scale purification remains problematic and expensive. The aim of this work was to establish the best process for obtaining C-phycocyanin of different purities for different applications. The first step of this study was the maximization of the ultrafiltration process. Under the best ultrafiltration conditions, ...
Source: Brazilian Journal of Chemical Engineering - January 21, 2019 Category: Chemistry Source Type: research

Optimization of preparation conditions for activated carbons from polyethylene terephthalate using response surface methodology
Abstract This work proposes the optimal conditions for the preparation of activated carbons from polyethylene terephthalate (PET) with good surface area and yield. The PET-based activated carbon was prepared using a chemical activation technique employing sulfuric acid (H2SO4). Different preparation conditions involving impregnation ratio, activation temperature and activation time were investigated to evaluate their effects on both surface area and yield. The central composite design (CCD) approach was adopted to determine the effects of preparation conditions on responses. Based on the CCD, quadratic models for both surf...
Source: Brazilian Journal of Chemical Engineering - January 21, 2019 Category: Chemistry Source Type: research

EFFECT OF ETHANOL ON THE DRYING CHARACTERISTICS AND ON THE COUMARIN YIELD OF DRIED GUACO LEAVES (Mikania laevigata SCHULTZ BIP. EX BAKER)
In this study, the drying kinetics and coumarin yield of guaco leaves dried with and without treating the surface with ethanol were evaluated. The drying experiments were carried out in a forced convection tunnel at 50 and 60 ºC temperatures and air velocities of 0.42 and 0.84 m/s. The results show that the samples with ethanol experienced faster water evaporation during drying experiments, thereby reducing the drying time by up to 35%, and also had higher yields of coumarin. Storage experiments and color analysis were also performed. Treatment of dried guaco leaves with ethanol resulted in color degradation, but increase...
Source: Brazilian Journal of Chemical Engineering - January 21, 2019 Category: Chemistry Source Type: research

Predicting kappa number in a kraft pulp continuous digester: a comparison of forecasting methods
Abstract This paper discusses kappa number prediction models using Single Exponential Smoothing, Multiple Linear Regression Analysis, the Time Series Method of Box-Jenkins (ARIMA) and Artificial Neural Networks. Applying a database of an industrial eucalyptus Kraft pulp continuous digester, these four different methods were evaluated according to different statistical decision criteria. After fitting the parameters of the models, validations were performed using a new dataset. Results, advantages and limitations of the four methods were compared. Some statistical forecasting indexes indicate that the ARIMA model showed mor...
Source: Brazilian Journal of Chemical Engineering - January 21, 2019 Category: Chemistry Source Type: research

Model-based run-to-run optimization for process development
Abstract Research and development of new processes is a fundamental part of any innovative industry. For process engineers, finding optimal operating conditions for new processes from the early stages is a main issue, since it improves economic viability, helps others areas of R&D by avoiding product bottlenecks and shortens the time-to-market period. Model-based optimization strategies are helpful in doing so, but imperfect models with parametric or structural errors can lead to suboptimal operating conditions. In this work, a methodology that uses probabilistic tendency models that are constantly updated through expe...
Source: Brazilian Journal of Chemical Engineering - January 21, 2019 Category: Chemistry Source Type: research

Modeling of multiphase flow in an air-cooling system using the cfd-fsca approach
Abstract The deposition of crystallized ammonium salt particles presents serious damage to the hydrogenation reactor effluent air cooler (REAC) in petrochemical engineering. The correlation technology process was analyzed for predicting the particle deposition situation in air coolers. Moreover, the particle crystallization and deposition were revealed, and a mathematical model for flow field simulation was established by computational fluid dynamics (CFD). In addition, the fast search clustering algorithm (FSCA) realized in Matlab software was applied to detect tube anomaly. The relatively greater risk of deposition or bl...
Source: Brazilian Journal of Chemical Engineering - January 21, 2019 Category: Chemistry Source Type: research

Pyrolysis kinetics of hulless barley straw using the distributed activation energy model (daem) by the tg/dta technique and sem/xrd characterizations for hulless barley straw derived biochar
Abstract The pyrolysis kinetics of hulless barley straw at different heating rates of 5 ， 10, 15, 20 and 30 ºC/min were investigated via thermogravimetry, and the activation energy distribution E and pre-exponential factor k0 were calculated using the Distributed Activation Energy Model (DAEM) from thermogravimetric analysis (TGA) curves, and characterizations of pyrolysis product of biochar were analyze d by techniques of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The pyrolysis process consisted mainly of the dehydration stage (50-150 ºC), the active pyrolysis stage (200-400 ºC) and the passive p...
Source: Brazilian Journal of Chemical Engineering - January 21, 2019 Category: Chemistry Source Type: research

Reversibility of al-kaolin and al-humic aggregates monitored by stable diameter and size distribution
Abstract The reversibility of aggregates during flocculation was investigated. The stable diameter (d) and the power law slope coefficient of the particle size distribution ( β ) were applied to follow re-formation after breakage. A non-intrusive image-based technique was used for monitoring flocs. Aggregates were formed by adding alum [Al2(SO4)3 ·18H2O] by the sweep-coagulation mechanism to two synthetic waters, prepared from kaolin (Fluka) and humic acid (Aldrich Chemical). Velocity gradients (G) varied from 20 to 120 s-1 during experiments, and the rupture occurred under controlled conditions. After rupture, the initi...
Source: Brazilian Journal of Chemical Engineering - January 21, 2019 Category: Chemistry Source Type: research

Simulation of a direct reduction moving bed reactor using a three interface model
Abstract In the present study, the rate of reduction in the direct reduction moving bed reactor of a MIDREX plant has been studied. The reactor was modeled by a one-dimensional, nonisothermal, steady-state model. The three interface unreacted shrinking core model accounting for different iron oxides reduction was used for describing the reaction behaviors at the pellet scale. The quasi steady state assumption was used to calculate the gas species concentrations at the interfaces. The effects of external and internal mass transfer resistance through the pellets and heat transfer on the overall rate of reduction were conside...
Source: Brazilian Journal of Chemical Engineering - January 21, 2019 Category: Chemistry Source Type: research

Chemical interesterification of cotton oil with methyl acetate assisted by ultrasound for biodiesel production
In this study, research was performed on the interesterification reaction of cotton oil with methyl acetate, using potassium methoxide as catalyst, in the presence of ultrasonic waves. In order to obtain a better understanding of the process variables behavior, a response surface methodology was used along with statistical methods. The experiments were performed with molar ratio varying from 1:8 to 1:24, catalyst percentage of 0.1 to 1.3% (weight), ultrasonic nozzle amplitude varying from 30% to 90% (180 to 540 W) and vibration pulse varying from 50% to 90%. Process variables were optimized with the optimal molar ratio of ...
Source: Brazilian Journal of Chemical Engineering - January 21, 2019 Category: Chemistry Source Type: research

Estimation of the kinetic parameters for h2o2 enzymatic decomposition and for catalase deactivation
Abstract Catalase is a potentially useful biocatalyst in various industrial bioprocesses (textile industry, food processing, and pulp and paper) that require removal of hydrogen peroxide. This process can be achieved in such reactors even under isothermal conditions. However, it is usually connected with a long duration of the process or with spending a considerable amount of biocatalyst for a unit mass of the transformed substrate, which in turn leads to an increase in operating costs. They can be limited by applying the optimal temperature control, which requires the values of the thermodynamic parameters -the activation...
Source: Brazilian Journal of Chemical Engineering - January 21, 2019 Category: Chemistry Source Type: research