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.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 9, 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. The ...
Source: Brazilian Journal of Chemical Engineering - December 9, 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 9, 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 9, 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 9, 2019 Category: Chemistry Source Type: research
SIMULTANEOUS LIPID AND CAROTENOID PRODUCTION BY STEPWISE FED-BATCH CULTIVATION OF Rhodotorula mucilaginosa WITH CRUDE GLYCEROL
Abstract In the present study, an innovative cultivation strategy of Rhodotorula mucilaginosa CCT 7688 to accumulate both lipids and high added value carotenoids was proposed, with the potential to contribute to the economic feasibility of microbial oils in comparison with vegetable oils. The stepwise fed-batch cultivation with crude glycerol feeding at 24 h, 96 h, and 144 h, with the addition of magnesium to the initial culture medium, resulted in a lipid content of 51.0 ± 0.3 % CDW, biomass concentration of 21.00 ± 0.48 g L-1, total lipid production of 10.72 ± 0.18 g L-1, lipid productivity of 0.037 ± 0.001 g L-1 h-1...
Source: Brazilian Journal of Chemical Engineering - December 9, 2019 Category: Chemistry Source Type: research
LIPASE - CATALYZED FORMATION OF PENTYL NONANOATE USING SCREENED IMMOBILIZED LIPASE FROM Rhizomucor meihei
In this study, the synthesis of pentyl nonanoate ester (a short chain ester with fruity aroma) was carried out with a commercial immobilized lipase from Rhizomucor meihei Lipozyme (RMIM) as biocatalyst in the esterification reaction between nonanoic acid and pentanol. Various reaction parameters such as enzyme concentration, substrate concentration, reaction temperature and reaction time in solvent-free system were screened to enhance the ester formation with the best yield. A maximum yield for pentyl nonanoate (86.08 %) in a solvent-free system was obtained within 150 min, at a reaction temperature of 45 OC, molar ratio o...
Source: Brazilian Journal of Chemical Engineering - December 9, 2019 Category: Chemistry Source Type: research
Density calculations of aqueous amine solutions using an excess gibbs based model
Abstract Accurate representation of the physical properties of a solvent is essential for design and simulation of processes. Density and viscosity, for instance, have an important role in modelling and designing absorption and desorption towers. In the present work, a model to accurately calculate the density of aqueous amine solutions used in CO2 capture was developed as a function of temperature and composition. The model is based on excess Gibbs energy functions, and in this work the functional form of the non-random two-liquid (NRTL) model was used. The model is able to accurately represent the density of the tested s...
Source: Brazilian Journal of Chemical Engineering - December 9, 2019 Category: Chemistry Source Type: research
ENERGETIC ANALYSIS OF AN ABSORPTION CHILLER USING NH3/LiNO3 AS AN ALTERNATIVE WORKING FLUID
Abstract This paper presents a thermodynamic model developed for a prototype absorption chiller using NH3/LiNO3 with 10 kW of nominal capacity. The study was undertaken using thermodynamic modeling based on the mass and energy balance, takes the overall heat transfer coefficients into consideration and uses the characteristic equation method. First, the results obtained from the thermodynamic modeling developed were compared with those obtained from the characteristic equations of thermal power activation and the cooling capacity. These showed good agreement with the experimental data, there being maximum relative errors o...
Source: Brazilian Journal of Chemical Engineering - October 1, 2019 Category: Chemistry Source Type: research
Phase behavior data and thermodynamic modeling of the binary system {co2 + coumarin} at high pressures
Abstract In this work, vapor - liquid (VLE) equilibrium for the binary system carbon dioxide (1) + coumarin (2) at high pressures was measured by a static synthetic method using a variable-volume view cell. Experimental data were obtained in the temperature range of 318 - 338 K and pressures up to 20 MPa. Coumarin molar fraction ranged from 3.0x10-3 to 6.0x10-3. Coumarin melting point reduction at high pressures was observed. The experimental results were modeled using the Peng-Robinson (PR) equation of state with van der Waals quadratic mixing rules (vdW - QMRs), providing a good representation of the experimental phase e...
Source: Brazilian Journal of Chemical Engineering - October 1, 2019 Category: Chemistry Source Type: research
ETHANOLIC AND HYDROALCOHOLIC EXTRACTS OF PITANGA LEAVES (Eugenia uniflora L.) AND THEIR FRACTIONATION BY SUPERCRITICAL TECHNOLOGY
Abstract Hydroalcoholic extracts prepared by conventional methods (in stirred vessel at 25 °C and 1 bar) and, hydroalcoholic and supercritical carbon dioxide (scCO2) extracts prepared in fixed bed extractors (60 ºC and 400 bar) were obtained from pitanga leaves (Eugenia uniflora L.) in order to recover phenolic compounds. Hydroalcoholic and ethanolic extracts obtained in fixed bed were further fractionated in four separators by gradual pressure reduction, using scCO2 as an antisolvent. All extracts and fractions were characterized in terms of extraction yield and the presence of total phenolics and flavonoids. Solvents w...
Source: Brazilian Journal of Chemical Engineering - October 1, 2019 Category: Chemistry Source Type: research
Bromelain separation and purification processes from pineapple extract
Abstract The concern about the effective use of agro-industrial residues from the food industry has increased. Bromelain is an enzyme mainly obtained from the pineapple plant (A. comosus), including its parts normally considered as waste. It is a high value-added product with a wide variety of applications such as in food, cosmetic and pharmaceutical industries. Many approaches have been used to purify this enzyme, but an efficient method to produce highly active and pure bromelain is still highly desirable. The investigated methods include ion exchange chromatography, precipitation, an aqueous two-phase system as well as ...
Source: Brazilian Journal of Chemical Engineering - October 1, 2019 Category: Chemistry Source Type: research
Synthesis of morpholine-based ionic liquids for extractive desulfurization of diesel fuel
Abstract Extractive desulfurization with ionic liquids has attracted significant attention from a growing number of scientists due to the current environmental restrictions on fuel. Protic ionic liquids (PILs) were synthesized via equimolar neutralization of morpholine and formic-based compounds. The obtained PILs were characterized by Fourier transform infrared and 1H NMR spectroscopy and used as a promoter for the room temperature deep desulfurization of model oil and commercial B0S500 diesel. Extractive desulfurization of the model oil in n-octane showed that the alkyl chain length of the ionic liquid [Nmorph]+[HCOO]- d...
Source: Brazilian Journal of Chemical Engineering - October 1, 2019 Category: Chemistry Source Type: research
Application of response surface methodology for lipase catalyzed synthesis of 2-ethylhexyl palmitate in a solvent free system using ultrasound
This study aims at clean production of 2-ethylhexyl palmitate catalyzed by lipase Fermase CALB 10000 in a solvent-free system using ultrasound technology. The central composite design (CCD) of response surface methodology with 4 factors at 3 levels consisting of acid to alcohol molar ratio (1:3-1:7), enzyme loading (3 %-7% (w/w)), ultrasound power (60 - 100 W) and duty cycle (30%-70 %) was used for optimization of the reaction. All the reactions were carried out at a fixed temperature of 60 °C, 200 rpm and reaction time (120 min). The statistical software, Design-Expert 9.0, was used for regression analysis and graphical ...
Source: Brazilian Journal of Chemical Engineering - October 1, 2019 Category: Chemistry Source Type: research
Ultrasound-assisted transesterification of soybean oil using combi-lipase biocatalysts
Abstract We applied ultrasonic technology for the transesterification of soybean oil catalyzed by a mixture of lipases (combi-lipase: 75 % Novozym 435; 10 % Lipozyme TL-IM; and 15 % Lipozyme RM-IM), verifying the effects of ultrasonic amplitude, pulse conditions, the ethanol:oil molar ratio, enzyme concentration, and the influence of solvent (tert-butanol on the reaction. We also compared this system against ultrasound combined with mechanical stirring, and the efficiency of the combi-lipase, compared with the individual use of each lipase. The optimum conditions for the transesterification reaction were determined as enzy...
Source: Brazilian Journal of Chemical Engineering - October 1, 2019 Category: Chemistry Source Type: research
