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Brazilian Journal of Chemical Engineering, Volume: 30, Número: 2, Publicado: 2013
  • Valorization of agroindustrial solid residues and residues from biofuel production chains by thermochemical conversion: a review, citing Brazil as a case study Reviews

    Virmond, E.; Rocha, J. D.; Moreira, R. F. P. M.; José, H. J.

    Resumo em Inglês:

    Besides high industrial development, Brazil is also an agribusiness country. Each year about 330 million metrics tons (Mg) of biomass residues are generated, requiring tremendous effort to develop biomass systems in which production, conversion and utilization of bio-based products are carried out efficiently and under environmentally sustainable conditions. For the production of biofuels, organic chemicals and materials, it is envisaged to follow a biorefinery model which includes modern and proven green chemical technologies such as bioprocessing, pyrolysis, gasification, Fischer-Tropsch synthesis and other catalytic processes in order to make more complex molecules and materials on which a future sustainable society will be based. This paper presents promising options for valorization of Brazilian agroindustrial biomass sources and residues originating from the biofuel production chains as renewable energy sources and addresses the main aspects of the thermochemical technologies which have been applied.
  • Optimization of the precipitation of clavulanic acid from fermented broth using t-octylamine as intermediate Bioprocess Engineering

    Hirata, D. B.; Oliveira, J. H. H. L.; Leão, K. V.; Rodrigues, M. I.; Ferreira, A. G.; Giulietti, M.; Barboza, M.; Hokka, C. O.

    Resumo em Inglês:

    This work describes the use of clavulanic acid (CA) precipitation as the final step in the process of purification of CA from fermentation broth as an alternative to conventional methods employed traditionally. The purpose of this study was to use a stable intermediate (t-octylamine) between the conversion of CA to its salt form (potassium clavulanate), thereby enabling the resulting intermediate (amine salt of clavulanic acid) to improve the purification process and maintain the stability of the resulting potassium clavulanate. To this end, response surface methodology was employed to optimize the precipitation step. For the first reaction, five temperatures (6.6 to 23.4 ºC), concentrations of clavulanic acid in organic solvent (6.6 to 23.4 mg/mL) and t-octylamine inflow rates (0.33 to 1.17 drop/min) were selected based on a central composite rotatable design (CCRD). For the second reaction, five temperatures (11.6 to 28.4 ºC), concentrations of clavulanic acid amine salt in organic solvent (8.2 to 41.8 mg/mL) and concentrations of potassium 2-ethylhexanoate (0.2 to 1.2 molar) were also selected using CCRD. From these results, precipitation conditions were selected and applied to the purification of CA from the fermentation broth, obtaining a yield of 72.37%.
  • Recombinant Erwinia carotovora l-asparaginase II production in Escherichia coli fed-batch cultures Bioprocess Engineering

    Roth, G.; Nunes, J. E. S.; Rosado, L. A.; Bizarro, C. V.; Volpato, G.; Nunes, C. P.; Renard, G.; Basso, L. A.; Santos, D. S.; Chies, J. M.

    Resumo em Inglês:

    Asparaginases are the cornerstone therapy of many successful combination regimens for the treatment of acute lymphoblastic leukemia (ALL), the most common malignancy in children and adolescents. The aim of this work was to produce recombinant Erwinia carotovora L-asparaginase II in Escherichia coli fed-batch cultures. Using a robust fed-batch technique with pre-determined exponential feeding rates, our bioreactor culture system yielded 30.7 grams of dry cell weight and 0.9 grams of soluble rErAII protein per liter of culture broth. The homogeneous rErAII activity was determined by isothermal titration calorimetry (ITC). The enzyme Km values for the main substrates L-Asn and L-Gln were 33x10-6 M and 10x10-3 M, respectively. Our work shows that it is possible to produce an active homogeneous rErAII enzyme in the soluble cell fraction through IPTG-induced E. coli fed-batch cultivation.
  • Production of clavulanic acid and cephamycin C by Streptomyces clavuligerus under different fed-batch conditions Bioprocess Engineering

    Bellão, C.; Antonio, T.; Araujo, M. L. G. C.; Badino, A. C.

    Resumo em Inglês:

    The effect of carbon source and feeding conditions on the production of clavulanic acid (CA) and cephamycin C (CephC) by Streptomyces clavuligerus was investigated. In fed-batch experiments performed with glycerol feeding, production of CA exceeded that of CephC, and reached 1022 mg.L-1. Highest CephC production (566.5 mg.L-1) was obtained in fed-batch cultivation with glycerol feeding. In fed-batch experiments performed with starch feeding, the production of CephC was in general higher than that of CA. A dissociation index (DI) was used to identify feeding conditions that favored production of CephC relative to CA. In all cultures with glycerol, DI values were less than unity, indicating higher production of CA compared to CephC. Conversely, in cultures fed with starch, the DI values obtained were greater than unity. However, no carbon source or feeding condition was able to completely dissociate the production of CA from that of CephC.
  • Immobilized Lactobacillus acidophilus produced from whey and alginate Bioprocess Engineering

    Rosa, P. R.; Sá, E. M.; Coutinho Filho, U.; Cardoso, V. L.

    Resumo em Inglês:

    An analysis was made of the use of whey fermentation by Lactobacillus acidophilus LA-5 for encapsulated probiotic bacteria cell production. Fermentation was done in a 2-liter Biostat B Fermentor at 28±1 ºC without air supply and agitation maintained at 200 rpm. Different processing conditions were studied using Center Composite Design applied to Surface Response Methodology. Maximum cell yield (2.7 x10(10) NMP/mL for 36 hours) was achieved with 30.85 g/L of lactose, a pH value of 6.45 and 1.04 g/L of inoculum. Cell growth was evaluated using reconstituted and fresh whey after 144 hours of fermentation in pre-optimized conditions. Cell concentration after fermentation was 10(10) MPN/mL in all the assays. The Verhulst model proved to be satisfactory to fit the experimental results, providing a stationary cell concentration of 6.0 g/L and a specific growth rate of 0.09 h-1. Cells were collected by centrifugation at 15000g for 5 minutes at 4 ºC, immobilized in 2% alginate, and dried to a constant weight at 50 ºC. Immobilized probiotic cells presented 10(11) MPN/g, a time required to kill 90% of the organisms (D value) of 18 h (70 ºC), an activation energy of 76.04 kJ/mol for thermal inactivation, and an in vitro resistance to low pH (D value of 62.5 min at 37 ºC, pH 2.5).
  • Spirulina sp. LEB-18 culture using effluent from the anaerobic digestion Bioprocess Engineering

    Borges, J. A.; Rosa, G. M.; Meza, L. H. R.; Henrard, A. A.; Souza, M. R. A. Z.; Costa, J. A. V.

    Resumo em Inglês:

    The carbon source is the most expensive nutrient for Spirulina production; effluents from anaerobic digestion contain this nutrient in the form of HCO3-. The aim of this study was to assess the growth kinetics, composition and fatty acid profile of Spirulina sp. LEB-18 grown in standard Zarrouk medium (NaHCO3 16.8 g L-1) and in Zarrouk medium replaced with 20% (v/v) effluent with reduced concentrations of NaHCO3 (5.3 and 2.8 g L-1). The use of effluent and lower concentrations of HCO3 was found to be an alternative to reduce the costs of Spirulina production, because there were no significant differences in growth parameters (µmax 0.324 - 0.354 d-1; Pmax 0.280 - 0.297 g L-1 d-1), in the different culture medium used. Lipids ranged between 4.9 and 5.0%; the media with effluent had higher levels of linoleic acid compared to the standard medium.
  • Evaluation of wavelength selection methods for 2D fluorescence spectra applied to bioprocesses characterization Bioprocess Engineering

    Masiero, S. S.; Trierweiler, J. O.; Farenzena, M.; Escobar, M.; Trierweiler, L. F.; Ranzan, C.

    Resumo em Inglês:

    In biotechnological processes, the productivity and costs depend strongly on the control of the operating conditions. For this reason, sensors that allow the monitoring of variables of interest become quite important. 2D fluorescence spectroscopy is one promising option among those that are being applied for this purpose. In the present work, three methods were evaluated to select the best excitation/emission wavelength pairs of 2D fluorescence spectra to infer product, substrate and cellular concentrations throughout a fermentation using a multiple linear chemometric model: Exhaustive Search (ES), Stepwise Regression and Genetic Algorithm (GA). The Stepwise Regression presented unsatisfying results, while GA always led to good R² values in short computational times. However, for the proposed problem, the ES showed the best performance, finding the global optimum in a few minutes.
  • The behaviour of an anaerobic baffled reactor (ABR) as the first stage in the biological treatment of hog farming effluents Environmental Engineering

    Motteran, F.; Pereira, E. L.; Campos, C. M. M.

    Resumo em Inglês:

    This present paper reports a study of the efficiency of an anaerobic Baffled Reactor (ABR) composed of three chambers working as the first stage of a biological treatment system for swine wastewater, over a period of 116 days. The average value of the volumetric organic loading rate (VOLR) was 17.8 kgCODtotal m-3 d-1, the biological organic loading rates (BOLR) based on total and filtered COD influents of 14381 mg L-1 and 3610 mg L-1, respectively, were: 1.3 kgCODtotal kgTVS d-1 and 0.98 kgCODfiltered kgTVS d-1, respectively, and the hydraulic loading rate (HLR) was about 1.4 m³ m-3 d-1. The average removal efficiency for total COD was 80% at a hydraulic retention time (HRT) of about 18 hours. The average alkalinity in the effluent was 3801 mgCaCO3 L-1. The average removal efficiencies for oil and grease and total soluble solids were 41% and 78%, respectively. The sludge granulation and biogas production in the ABR were quite different between the first and third compartment, showing a distinct microbial consortium in each chamber. Through this research it was confirmed that this type of reactor can be employed as the first stage in a system treating swine wastewater.
  • Heat transfer to immiscible liquid mixtures in a spiral plate heat exchanger Fluid Dynamics; Heat And Mass Transfer; And Other Topics

    Sathiyan, S.; Rangarajan, Murali; Ramachandran, S.

    Resumo em Inglês:

    This work presents new predictive correlations for heat transfer to immiscible liquid-liquid mixtures in a spiral plate heat exchanger. Liquid-liquid heat transfer studies were carried out in spiral plate heat exchangers for the water-octane, water-kerosene, and water-dodecane systems. For each composition of the mixture, the mass flow rate of the cold fluid was varied, keeping that of the hot fluid and the fluid inlet temperatures constant. Two-phase cold flow rates were in the laminar range, while the hot fluid flow was turbulent. Calculations of the LMTD (log mean temperature difference) correction factor showed that the flow was countercurrent. Heat transfer coefficients of the two-phase liquids were found to be strongly dependent on the composition of the liquid mixture and exhibited abrupt transitions as a function of the compositions. Given the absence of predictive correlations in the literature that sufficiently capture this compositiondependence, new empirical correlations were developed using part of the experimental data, with the composition of the cold fluid as an explicit variable. Statistical analysis of the regression yielded satisfactory results. The correlations were tested against the rest of the experimental data and were found to predict heat transfer coefficients within ± 15%. These preliminary studies should be useful in designing compact exchangers for handling two-phase water-organics mixtures.
  • Verification and validation in CFD for a free-surface gas-liquid flow in channels Fluid Dynamics; Heat And Mass Transfer; And Other Topics

    Soares, C.; Noriler, D.; Wolf Maciel, M. R.; Barros, A. A. C.; Meier, H. F.

    Resumo em Inglês:

    This work deals with experimental and numerical studies of a 3-D transient free-surface two-phase flow in a bench-scale channel flow. The aim was to determine how well the homogeneous model can predict the fluid dynamics behavior and to validate the model. The model was validated with experimental data acquired for two hydrodynamic situations. The mathematical model was based on the mass conservation equations for liquid and gas phases and on the momentum conservation equation for the mixture, assuming interpenetrating, continuum and homogeneous hypotheses. Turbulence has been considered for the mixture through the standard k-ε model. The numerical methods were the finite volume method with pressure-velocity coupling and a numerical grid on a generalized Cartesian coordinate system. Good qualitative and quantitative agreements were found for both cases, making the prediction of the fluid dynamics behavior quite robust.
  • Effect of drying temperature on the nutritional and antioxidant qualities of cumari peppers from Pará (Capsicum chinense Jacqui) Fluid Dynamics; Heat And Mass Transfer; And Other Topics

    Reis, R. C.; Castro, V. C.; Devilla, I. A.; Oliveira, C. A.; Barbosa, L. S.; Rodovalho, R.

    Resumo em Inglês:

    This study evaluated the proximate components, concentration of total polyphenols, antioxidant activity, and capsaicin and dihydrocapsaicin in the Cumari chili pepper from Pará, Brazil (Capsicum chinense Jacqui) both fresh and after subjected to three different drying temperatures. The results showed that the contents of ash and vitamin C for the dried pepper differed significantly (P <0.05) compared with the fresh pepper. There was a significant difference in concentrations of total phenolics, antioxidant activity and capsaicinoids between the fresh pepper and those submitted to the drying treatments. It was concluded that higher temperatures increase shelf life and decrease the volume of the product, preserve macronutrients and degrade micronutrients, antioxidants and the spicy hotness of the Cumari pepper.
  • Modification of PSf membrane nanostructure using different fabrication parameters and investigation of the CO2 separation properties of PDMS-coated PSf composite membranes Kinetics And Catalysis; Reaction Enginneering; And Materials Science

    Pakizeh, M.; Mansoori, S. A. A.; Pourafshari Chenar, M.; Namvar-Mahboub, M.

    Resumo em Inglês:

    The effects of preparation parameters on the performance and morphology of polydimethylsiloxane/ polysulfone (PDMS/PSf) membranes were investigated. The PDMS layer is mainly used for sealing the defects of the PSf selective layer. The membrane morphologies were characterized by using scanning electron microscopy (SEM). The CO2/CH4 separation performance of membranes was studied by a pure gas permeation experimental set up. According to the SEM results, decreasing the water/N,N-dimethylacetamide (DMAc) ratio as the coagulation medium from pure water to mixture of 90 vol.% DMAc and 10 vol.% water resulted in complete disappearance of macrovoids and also a lowering of the membrane selectivity. Permselectivity results showed that the ideal CO2/CH4 separation factor of the membranes was improved by the presence of the non-solvent additive to the polymer solution. It was also observed that reduction of the coagulation bath temperature (CBT) led to elimination of macrovoids which affect gas separation performance. Using methanol as a coagulant resulted in a less selective membrane compared with ethanol and water as coagulants and the CO2 permeance was about 3 and 9 times greater than with ethanol and water as coagulants, respectively.
  • Parametric study of hydrogen production from ethanol steam reforming in a membrane microreactor Kinetics And Catalysis; Reaction Enginneering; And Materials Science

    de-Souza, M.; Zanin, G. M.; Moraes, F. F.

    Resumo em Inglês:

    Microreactors are miniaturized chemical reaction systems, which contain reaction channels with characteristic dimensions in the range of 10-500 µm. One possible application for microreactors is the conversion of ethanol to hydrogen used in fuel cells to generate electricity. In this paper a rigorous isothermal, steady-state two-dimensional model was developed to simulate the behavior of a membrane microreactor based on the hydrogen yield from ethanol steam reforming. Furthermore, this membrane microreactor is compared to a membraneless microreactor. A potential advantage of the membrane microreactor is the fact that both ethanol steam reforming and the separation of hydrogen by a permselective membrane occur in one single microdevice. The simulation results for steam reforming yields are in agreement with experimental data found in the literature. The results show that the membrane microreactorpermits a hydrogen yield of up to 0.833 which is more than twice that generated by the membraneless reactor. More than 80% of the generated hydrogen permeates through the membrane and, due to its high selectivity, the membrane microreactor delivers high-purity hydrogen to the fuel cell.
  • Poly(3-hydroxybutyrate-co-3- hydroxyvalerate) nanoparticles prepared by a miniemulsion/solvent evaporation technique: effect of phbv molar mass and concentration Kinetics And Catalysis; Reaction Enginneering; And Materials Science

    Leimann, F. V.; Cardozo Filho, L.; Sayer, C.; Araújo, P. H. H.

    Resumo em Inglês:

    Miniemulsification and emulsion/solvent evaporation techniques were combined to produce poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanoparticles. Those nanoparticles were prepared with different PHBV molar masses and PHBV concentrations to verify their effect on the final particle size. Nanoparticles with an average diameter of 133 nm were obtained when a low molar mass (Mw = 44,350 g/mol) polymer was used. On the other hand, when high molar mass PHBV (Mw = 369,900 g/mol) was used under the same operational conditions, nanoparticles with a 300 nm average diameter and a broader particle size distribution were formed. Results also showed that increasing the PHBV concentration led to an increase of the particle size and, when the polymer/costabilizer (PHBV/hexadecane) weight ratio was close to 1, nanocapsules (hexadecane core surrounded by a PHBV shell) were formed.
  • Synthesis and properties of collagen-g-poly(sodium acrylate-co-2-hydroxyethylacrylate) superabsorbent hydrogels Kinetics And Catalysis; Reaction Enginneering; And Materials Science

    Sadeghi, M.; Hosseinzadeh, H.

    Resumo em Inglês:

    Novel biopolymer-based superabsorbent hydrogels were prepared by grafting crosslinked poly(acrylic acid-co-2-hydroxyethyl acrylate) (PAA-co-PHEA) chains onto collagen backbones through a free radical polymerization method. The graft copolymerization reaction was carried out in a homogeneous medium and in the presence of ammonium persulfate (APS) as initiator and N,N '-methylene bisacrylamide (MBA) as crosslinker. A proposed mechanism for collagen-g-(PAA-co-PHEA) formation was suggested and the hydrogel structure was confirmed using FTIR spectroscopy and TGA thermal analysis. Moreover, the morphology of the samples was examined by scanning electron microscopy (SEM). The effect of concentration of MBA as well as AA/HEA weight ratio on the swelling capacity of the hydrogel was also studied. Furthermore, the water absorbency of hydrogels was measured in solutions with pH ranging 1 to 13. The collagen-based hydrogel exhibited a pH-responsive character, so that a swelling-deswelling pulsatile behavior was recorded at pHs 2 and 8. Preliminary swelling and deswelling behaviors of the hydrogels were also studied. Additionally, the hydrogels exhibited salt-sensitivity and cation exchange properties.
  • Up-gradation of MoO3 and separation of copper, iron, zinc from roasted molybdenum ore by a leaching process Separation Processes

    Lee, Jin-Young; Kumar, Jyothi Rajesh; Jeon, Ho-Seok; Kim, Joon-Soo

    Resumo em Inglês:

    The present research paper deals with the oxidation process of molybdenum ore. The main target of the present study is the up-gradation of MoO3 from roasted molybdenum ore by a leaching process without waste generation. The most important application of hydrometallurgical processing is the leaching process of the ore and it is the primary process to make pure metal from ore. The present investigations optimize the following experimental parameters to improve the concentration of MoO3 as well as the separation of copper, iron and zinc in roasted molybdenum ore: effect of acid concentration, temperature, pulp density and leaching time were studied systematically. The temperature study was carried out at 550-595 ºC for the oxidation process. The XRD result shows that oxidation process of molybdenum ore and SEM pictures were taken for particles before and after the oxidation process at 585 ºC for 360 min.
  • Effects of gas types and models on optimized gas fuelling station reservoir's pressure Thermodynamics

    Farzaneh-Gord, M.; Deymi-Dashtebayaz, M.; Rahbari, H. R.

    Resumo em Inglês:

    There are similar algorithms and infrastructure for storing gas fuels at CNG (Compressed Natural Gas) and CHG (Compressed Hydrogen Gas) fuelling stations. In these stations, the fuels are usually stored in the cascade storage system to utilize the stations more efficiently. The cascade storage system generally divides into three reservoirs, commonly termed low, medium and high-pressure reservoirs. The pressures within these reservoirs have huge effects on performance of the stations. In the current study, based on the laws of thermodynamics, conservation of mass and real/ideal gas assumptions, a theoretical analysis has been constructed to study the effects of gas types and models on performance of the stations. It is intended to determine the optimized reservoir pressures for these stations. The results reveal that the optimized pressure differs between the gas types. For ideal and real gas models in both stations (CNG and CHG), the optimized non-dimensional low pressure-reservoir pressure is found to be 0.22. The optimized non-dimensional medium-pressure reservoir pressure is the same for the stations, and equal to 0.58.
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