Showing papers in "Brazilian Journal of Chemical Engineering in 2015"
TL;DR: In this article, a sugarcane bagasse was pretreated by four different methods: combined acid and alkaline, combined hydrothermal and acid-and-alkaline, alkaline and peroxide pretreatment, and enzymatic hydrolysis.
Abstract: Glucose production from sugarcane bagasse was investigated. Sugarcane bagasse was pretreated by four different methods: combined acid and alkaline, combined hydrothermal and alkaline, alkaline, and peroxide pretreatment. The raw material and the solid fraction of the pretreated bagasse were characterized according to the composition, SEM, X-ray and FTIR analysis. Glucose production after enzymatic hydrolysis of the pretreated bagasse was also evaluated. All these results were used to develop relationships between these parameters to understand better and improve this process. The results showed that the alkaline pretreatment, using sodium hydroxide, was able to reduce the amount of lignin in the sugarcane bagasse, leading to a better performance in glucose production after the pretreatment process and enzymatic hydrolysis. A good xylose production was also observed.
128 citations
TL;DR: In this paper, various water and oil-soluble demulsifiers were selected for separation of water from crude oil emulsions and their productivity measured using the bottle test method at 70 °C and 10 ppm concentration.
Abstract: In this study, various water-soluble and oil-soluble demulsifiers were selected for separation of water from crude oil emulsions and their productivity measured using the Bottle-test method at 70 °C and 10 ppm concentration The best ones among 23 demulsifiers examined through the screening process were fatty alcohol ethoxylate, triethanol amine and urea from the water-soluble group and Basororol E2032, Basorol PDB 9935 and TOMAC from the oil-soluble category Furthermore, the present study investigated the factors effective for demulsification such as temperature, concentration, pH, salinity and modifiers It was found that the separation improves with increasing demulsifier concentration, increasing salt content, increasing temperature up to 80 °C, keeping the pH values between 5-9 Adding solvent modifiers proved unnecessary Two formulations were prepared based on suggested optimal concentrations of demulsifier content by experimental design using Qualitec 4 and these proved to be highly effective in treating real and synthetic emulsions
83 citations
TL;DR: In this paper, the production of 5-hydroxymethylfurfural (HMF) from fructose dehydration was studied using H3PO4 as catalyst, in an organic/water system with different solvents (acetone, 2-butanol and ethyl ether).
Abstract: 5-Hydroxymethylfurfural (HMF) is a key renewable platform compound for production of fuels and chemical intermediates. The production of 5-hydroxymethylfurfural (HMF) from fructose dehydration was studied using H3PO4 as catalyst, in organic/water system with different solvents (acetone, 2-butanol and ethyl ether). The effect of fructose concentration, temperature and acid concentration was investigated in acetone/water medium. The increase in fructose concentration favors the formation of condensation products and rehydration products are favored at high acid concentration. The solvents exhibited similar performance when the volume ratio of organic to aqueous phase was 1:1, but when this ratio increases to 2:1, the HMF yield obtained with ether was much lower. NaCl addition to the aqueous phase promoted the extraction of HMF to the organic phase, with an HMF yield of 80% in the case of 2:1 acetone/water medium.
62 citations
TL;DR: In this paper, hydrophilic hydrogels were employed to remove the water content in biodiesel and diesel fuel samples, starting with samples that had 2160 ppm and 240 ppm of water, respectively.
Abstract: The removal of water content present in fuels such as biodiesel and diesel is quite important to adequate the fuel to standards for commercialization and to avoid corrosion of storage tanks and injection equipment in diesel engines. In this study, hydrophilic hydrogels were employed to remove the water content in biodiesel and diesel fuel samples. The results showed that the hydrogels were capable of decreasing the free water content and also the soluble water content present in the samples. The highest decrease of total water content in samples of biodiesel was 53.3% wt and for diesel samples the reduction of water content was 32.0%, starting with samples that had 2160 ppm and 240 ppm of water, respectively. The highest decrease of total water content (free and soluble water) for diesel samples was 80.4% wt, from a diesel sample initially containing 348 ppm of total water content.
41 citations
TL;DR: In this article, an empirical equation of state for fitting the (p, ρ,T) data of the ionic liquid 1-butyl-3methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIM][NTF2] was developed as a function of pressure and temperature.
Abstract: Pressure-density-temperature (p, ρ ,T) data of the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIM][NTF2] at T = (273.15 to 413.15) K and pressures up to p =140 MPa are reported with an estimated experimental relative combined standard uncertainty of Δ ρ / ρ = ±(0.01 to 0.08)% in density. The measurements were carried out with a newly constructed Anton-Paar DMA HPM vibration-tube densimeter. The system was calibrated using double-distilled water, aqueous NaCl solution, methanol, toluene and acetone. An empirical equation of state for fitting the (p, ρ ,T) data of [BMIM][NTF2] has been developed as a function of pressure and temperature. This equation is used for the calculation of the thermophysical properties of the ionic liquid, such as isothermal compressibility, isobaric thermal expansibility, thermal pressure coefficient, internal pressure, isobaric and isochoric heat capacities, speed of sound and isentropic expansibility.
41 citations
TL;DR: In this article, the production and characterization of cellulase from thermophilic strain Bacillus sp. C1AC5507 was studied and the optimum temperature and pH for the CMCase production were 70 °C and 7.0, respectively.
Abstract: The production and characterization of cellulase from thermophilic strain Bacillus sp. C1AC5507 was studied. For enzyme production, sugarcane bagasse was used as carbon source. The produced carboxymethyl cellulase (CMCase) had a molecular weight around 55 kDa and its activity varied between 0.14 and 0.37 IU mL-1 in conditions predicted by Response Surface Methodology. The optimum temperature and pH for the CMCase production were 70 °C and 7.0, respectively. The enzyme activity was inhibited mostly by Cu+2 and activated mostly by Co+2, Mn2+, Ca+2 and Fe+3. Our findings provide a contribution to the use of natural wastes such as sugarcane bagasse as substrate for growth and production of thermophilic CMCase. Further optimization to increase the production of cellulase enables the use in industrial applications.
38 citations
TL;DR: In this paper, a new surfactant, sodium methyl ester sulfonate (SMES), was synthesized using ricinoleic acid methyl esters, which is obtained from castor oil, for enhanced oil recovery in petroleum industries.
Abstract: Attention has been given to reduce the cost of surfactant by using castor oil as an alternative natural source of feedstock. A new surfactant, sodium methyl ester sulfonate (SMES) was synthesised using ricinoleic acid methyl ester, which is obtained from castor oil, for enhanced oil recovery in petroleum industries. The performance of SMES was studied by measuring the surface tension with and without sodium chloride and its thermal stability at reservoir temperature. SMES exhibited good surface activity, reducing the surface tension of surfactant solution up to 38.4 mN/m and 27.6 mN/m without and with NaCl, respectively. During the thermal analysis of SMES, a 31.2% mass loss was observed from 70 ˚C to 500 ˚C. The phase behavior of the cosurfactant/SMES-oil-water system plays a key role in interpreting the performance of enhanced oil recovery by microemulsion techniques. Flooding experiments were performed using a 0.5 pore volume of synthesized SMES solutions at three different concentrations. In each case chase water was used to maintain the pressure gradient. The additional recoveries in surfactant flooding were found to be 24.53%, 26.04% and 27.31% for 0.5, 0.6 and 0.7 mass% of surfactant solutions, respectively.
37 citations
TL;DR: In this paper, a review of methods used to prepare the adsorbents, along with their adsorption capacity for removal of different dyes from effluents is presented.
Abstract: Industries engaged in dyeing operation generate coloured effluent due to the presence of spent dyes Adsorption is among the various treatment processes employed for removal of dyes from effluents Activated carbon is mostly used as an adsorbent in the treatment process Attempts have been made by researchers to use non-conventional, low-cost, naturally-occurring biomass as adsorbents, including fruit peals, seeds, leaves, bark, sawdust, straw, ash, sludge and others that are abundantly available The literature indicates that the dye adsorption capacities of these non-conventional biomasses largely depend on the methods of processing and the types of dyes This review highlights methods used to prepare the adsorbents, along with their adsorption capacity for removal of different dyes from effluents
35 citations
TL;DR: In this paper, the technical and economic feasibility of membrane bioreactors (MBR) followed by nanofiltration (NF) for dairy wastewater treatment in order to reuse the treated effluent was evaluated.
Abstract: This study evaluated the technical and economic feasibility of membrane bioreactors (MBR) followed by nanofiltration (NF) for dairy wastewater treatment in order to reuse the treated effluent. It was observed that the MBR efficiently removed the organic matter and color of the feed effluent; however, due to the high concentration of dissolved solids in the permeate, it was necessary to use nanofiltration as a polishing step. The final treated effluent could be reused in the industry for cooling, steam generation and cleaning of external areas. A preliminary economic analysis showed the feasibility of the proposed system. The internal rate of return was greater than or equal to 32% when membrane lifespan was at least 2 years and the depreciation time was 15 years. The total cost of the proposed treatment system ranged from R$ 9.99/m3 to R$ 6.82/m3, depending on membrane lifespan.
32 citations
TL;DR: In this paper, artificial neural networks (ANN) and central composite rotatable design (CCRD) have been applied to optimize the performance of nanofluid systems by measuring the stability and thermal conductivity ratio based on the critical independent variables such as temperature, particle volume fraction and the pH of the solution.
Abstract: Central composite rotatable design (CCRD) and artificial neural networks (ANN) have been applied to optimize the performance of nanofluid systems. In this regard, the performance was evaluated by measuring the stability and thermal conductivity ratio based on the critical independent variables such as temperature, particle volume fraction and the pH of the solution. A total of 20 experiments were accomplished for the construction of second-order polynomial equations for both target outputs. All the influential factors, their mutual effects and their quadratic terms were statistically validated by analysis of variance (ANOVA). According to the results, the predicted values were in reasonable agreement with the experimental data as more than 96% and 95% of the variation could be predicted by the respective models for zeta potential and thermal conductivity ratio. Also, ANN proved to be a very promising method in comparison with CCD for the purpose of process simulation due to the complexity involved in generalization of the nanofluid system.
31 citations
TL;DR: In this paper, the authors evaluated MSW gasification-combustion integrated technologies in terms of dioxin and furan emission, and compared the obtained data with literature results on incineration, to point out which operational features differentiate the release of pollutants by these two processes.
Abstract: Thermal treatment is an interesting strategy to dispose of municipal solid waste: it reduces the volume and weight of the material dumped in landfills and generates alternative energy. However, the process emits pollutants, such as dioxins and furans. The present study evaluated MSW gasification-combustion integrated technologies in terms of dioxin and furan emission; and compared the obtained data with literature results on incineration, to point out which operational features differentiate the release of pollutants by these two processes. The results show that the process of integrated gasification and combustion emitted 0.28 ng N-1 m-3, expressed in TEQ (Total Equivalent Toxicity), of PCDD/F, less than the maximum limits allowed by local and international laws, whereas incineration normally affords values above these limits and requires a gas treatment system. The distinct operational conditions of the two thermal processes, especially those related to temperature and the presence of oxygen and fixed carbon, led to a lower PCDD/F emission in gasification.
TL;DR: In this paper, the authors measured the densities and refractive index of binay mixtures of water with four protic ionic liquids, based on ammonium and fatty acids, under atmospheric pressure.
Abstract: Densities and refractive index of binay mixtures of water with four protic ionic liquids, based on ammonium and fatty acids, were measured at 298.15 and 323.15 K, under atmospheric pressure. Apparent and excess molar volumes were obtained by experiments and fitting data to the Redlich-Meyer (RM), Redlich-Kister (RK) and Prigogine-Flory-Patterson (PFP) equations. The molar volume values were high, suggesting strong ion-solvent interaction. The same interaction also became stronger as the temperature increased. Excess volume values were negative, indicating that packing efficiency ability or attractive interactions occurred in mixtures of ionic liquid + water. The errors (AARD) for the properties in excess were in the range of 1.8% to 7.2%. The PFP error for the apparent volume was in the range of 0.34% to 0.06%, lower than the RM error for the same property, which was in the range of 0.70 to 1.55%. The Gladstone-Dale model was applied to correlate the refractive index of the binary mixture with the density from the values of both pure components.
TL;DR: In this paper, the effects of water content and temperature were considered in the study of sedimentation velocity of water-oil emulsions, which yielded high settling velocities at low water contents, even when very small droplets were present.
Abstract: Water-in-oil (W/O) emulsions are complex mixtures generally found in crude oil production in reservoirs and processing equipment. Sedimentation studies of water-oil emulsions enable the analysis of the fluid dynamic behavior concerning separation of this system composed of two immiscible liquids. Gravitational settling was evaluated in this article for a model emulsion system consisting of water and a Brazilian crude oil diluted in a clear mineral oil as organic phase. The effects of water content and temperature were considered in the study of sedimentation velocity of water-oil emulsions. Water contents between 10% and 50 % and temperatures of 25, 40 and 60 oC were evaluated, and a Richardson-Zaki type correlation was obtained to calculate settling velocities as a function of the process variables investigated. Water contents and average droplet sizes were monitored at different levels in the settling equipment, thus enabling identification of the effect of these variables on the phenomena of sedimentation and coalescence of the emulsions studied. The results showed that the emulsion stability during sedimentation was governed by the emulsion water content, which yielded high settling velocities at low water contents, even when very small droplets were present. A quantitative analysis of the combined effects of drop size and droplet concentration supports the conclusion that a stronger effect is produced by the higher concentration of particles, compared with the relatively smaller effect of increasing the size of the droplets.
TL;DR: In this paper, the authors reviewed the cooling effects of hot aerosol fire suppression systems and discussed areas applying generation I, II or III hot fire extinguishing technologies, especially in areas involving delicate electrical and electronic equipments.
Abstract: Since the phase out of Halon extinguishers in the 1980s, hot aerosol fire suppression technology has gained much attention. Unlike traditional inert gas, foam, water mist and Halon fire suppression agents, hot aerosol fire extinguishing agents do not need to be driven out by pressurized gases and can extinguish class A, B, C, D and K fires at 30 to 200 g/m3. Generally, hot aerosol fire extinguishing technology has developed from a generation I oil tank suppression system to a generation III strontium salt based S-type system. S-type hot aerosol fire extinguishing technology greatly solves the corrosion problem of electrical devices and electronics compared to potassium salt based generation I & II hot aerosol fire extinguishing technology. As substitutes for Halon agents, the ODP and GWP values of hot fire extinguishing aerosols are nearly zero, but those fine aerosol particles can cause adverse health effects once inhaled by human. As for configurations of hot aerosol fire extinguishing devices, fixed or portable cylindrical canisters are the most common among generation II & III hot aerosol fire extinguishers across the world, while generation I hot aerosol fire suppression systems are integrated with the oil tank as a whole. Some countries like the U.S., Australia, Russia and China, etc. have already developed standards for manufacturing and quality control of hot aerosol fire extinguishing agents and norms for hot aerosol fire extinguishing system design under different fire protection scenarios. Coolants in hot aerosol fire suppression systems, which are responsible for reducing hot aerosol temperature to avoid secondary fire risk are reviewed for the first time. Cooling effects are generally achieved through vaporization and endothermic chemical decomposition of coolants. Finally, this review discussed areas applying generation I, II or III hot aerosol fire suppression technologies. The generation III hot aerosol fire extinguishing system is most applicable, especially in areas involving delicate electrical and electronic equipments. Nonetheless, developing a much cleaner, non-corrosive and highly efficient hot aerosol fire suppression system is still needed.
TL;DR: In this article, the leaching kinetics of malachite in ammonium sulfate solutions was investigated, and metallic copper was recovered by a cementation method from the resulting actual leach solution.
Abstract: Malachite ore is one of the most important of oxidized copper ores. Copper production can be performed by using this ore. In this work, the leaching kinetics of malachite in ammonium sulfate solutions was investigated, and metallic copper was recovered by a cementation method from the resulting actual leach solution. Copper (II) oxide was prepared by an isothermal oxidation method from the cement copper. In the leaching experiments, the effects of reaction temperature, particle size, and stirring speed on copper leaching from malachite ore were studied. In the cementation experiments, metallic zinc was used as the reductant metal to recover the copper from the solution. Thermal oxidation of cement copper was performed under isothermal conditions. It was found that the leaching rate increased with increasing stirring speed and temperature, and decreased with particle size. It was observed that the leaching reaction fit to diffusion through the product layer. The activation energy of the leaching process was determined to be 25.4 kJ/mol. It was determined that the copper content of the metallic product obtained by the cementation method increased up to 96%. It was found that copper oxide prepared from cement copper had a tenorite structure.
TL;DR: In this article, a polyethersulfone ultrafiltration membrane with the modifier gelatin at 0, 5, 10, 15 and 20 wt % using DMF as solvent by phase inversion process was studied.
Abstract: In this study polyethersulfone ultrafiltration membrane were prepared with the modifier gelatin at 0, 5, 10, 15 and 20 wt % using DMF as solvent by phase inversion process. Morphologies and characteristics of the membranes were investigated through the methods of SEM, XRD, contact angle measurements. The performance of the modified membrane for the treatment of leather and distillery wastewater through a deadend ultrafiltration process was studied. Morphological investigation showed that the 10% gelatin content in 90% PES results in a two layer structure with a porous top and homogeneous sub-layer with uniform number of pores on the surface. The pure water flux of the modified membrane increases with gelatin concentration, which results in better permeation for both leather and distillery wastewater. In addition to 80-90% reduction in BOD and COD, all modified PES UF membranes showed moderate removal of total suspended and dissolved solids, chlorides, sulphate, oil and grease, potassium, sodium and ammonical nitrogen, apart from color removal.
TL;DR: In this article, the authors investigated the phenomenon of Newtonian heating under the application of a uniform magnetic field when thermal-diffusion "Soret" and diffusion-thermo "Dufour" effects appeared in the energy and concentration equations in a flow of a Jeffery fluid.
Abstract: In this communication we have investigated the phenomenon of Newtonian heating under the application of a uniform magnetic field when thermal-diffusion "Soret" and diffusion-thermo "Dufour" effects appear in the energy and concentration equations in a flow of a Jeffery fluid. The flow is induced by the stretching of a disk in the radial direction. The solutions of the nonlinear equations governing the velocity, temperature and concentration profiles are solved analytically "using HAM" and graphical results for the resulting parameters are displayed and discussed. Numerical values of local Nusselt and Sherwood numbers for different values of physical parameters are computed and shown. It is shown that the magnetic field retards the flow, whereas Newtonian heating acts as a boosting agent which enhances the flow. It is also noted that the combined Soret and Dufour effects on the temperature and concentration profiles are opposite.
TL;DR: The performance of an in-situ capacitance sensor for on-line monitoring of biomass concentration was evaluated for some of the most important microorganisms in the biotechnology industry: Escherichia coli, Saccharomyces cerevisiae, Pichia pastoris and Bacillus megaterium.
Abstract: The performance of an in-situ capacitance sensor for on-line monitoring of biomass concentration was evaluated for some of the most important microorganisms in the biotechnology industry: Escherichia coli, Saccharomyces cerevisiae, Pichia pastoris and Bacillus megaterium. A total of 33 batch and fed-batch cultures were carried out in a bench-scale bioreactor and biomass formation trends were followed by dielectric measurements during the growth phase as well as the induction phase, for 5 recombinant E. coli strains. Permittivity measurements and viable cellular concentrations presented a linear correlation for all the studied conditions. In addition, the permittivity signal was further used for inference of the cellular growth rate. The estimated specific growth rates mirrored the main trends of the metabolic states of the different cells and they can be further used for setting-up control strategies in fed-batch cultures.
TL;DR: In this article, the limiting current density in an electrodialysis bench stack was determined for the treatment of an electroplating effluent containing HEDP, and the results demonstrated correlation between the regions defined by theory and the experimental data.
Abstract: Membrane separation techniques have been explored for treating industrial effluents to allow water reuse and component recovery. In an electrodialysis system, concentration polarization causes undesirable alterations in the ionic transportation mechanism. The graphic construction of the current voltage curve is proposed for establishing the value of the limiting current density applied to the cell. The aim of this work was to determine the limiting current density in an electrodialysis bench stack, the function of which was the treatment of an electroplating effluent containing HEDP. For this, a system with five compartments was used with a working solution simulating the rinse waters of HEDP-based baths. The results demonstrated correlation between the regions defined by theory and the experimental data.
TL;DR: The Catalytic Wet Air Oxidation (CWAO) of phenol using copper oxide catalysts supported by γ-Al2O3, TiO2, and pillared clay was evaluated to identify which of these catalysts was the most appropriate for this reaction.
Abstract: The Catalytic Wet Air Oxidation (CWAO) of phenol using copper oxide catalysts supported by γ-Al2O3, TiO2, and pillared clay was evaluated to identify which of these catalysts was the most appropriate for this reaction. The CuO/PILC, CuO/γ-Al2O3 and CuO/TiO2 catalysts were the most successful at removing phenol and resulted in more than 96% conversion. Among these catalysts, CuO/γ-Al2O3 produced the largest amount of CO2, the lowest amount of intermediate products and the lowest amount of copper leaching. These results showed that the CuO/γ-Al2O3catalyst was the best for the end of the reaction. However, the methods used in this study did not allow us to identify the most appropriate reaction time (or catalyst). An alternative approach for this problem was to quantify the costs for each reaction time. Using this approach, the CuO/γ-Al2O3 catalyst was the most economically favorable catalyst when it was used during the first hour of the reaction.
TL;DR: In this article, copolymeric and terpolymeric hydrogel-silver nanocomposites based on poly(acrylamideco-itaconic acid), poly(poly(acrylic acid-co-acrylonitrized polycyclic acid)-co-acetylhexane (PCA-Co-Athonymythropoietrate) and poly(acetylcyclic poly(ACP-CO-ACR) co-AcR) were synthesized by free-radical polymerization and characterized by Fourier Transform Infrared
Abstract: In this study, copolymeric and terpolymeric hydrogel-silver nanocomposites based on poly(acrylamideco-itaconic acid), poly(acrylic acid-co-itaconic acid) and poly(acrylic acid-co-acrylamide-co-itaconic acid) were synthesized by free-radical polymerization. These nanocomposites were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), UV-Visible Spectrophotometry (UV-Vis) and X-Ray Diffraction (XRD) analysis, as well as their swelling behaviors. In addition, antibacterial properties of these hydrogel-silver nanocomposites were investigated against Pseudomonas aeruginosa. Acrylic-based hydrogel-silver nanocomposites demonstrated antibacterial activity against Gram-negative bacteria. These hydrogel-silver nanocomposites can be used as antibacterial material in the medical field.
TL;DR: In this paper, the influence of the initiation on droplet nucleation is discussed and the result of employing different initiator systems on the nucleation mechanism and kinetics in the polymerization of stable styrene/polystyrene miniemulsions with varied droplet size is discussed.
Abstract: In miniemulsion polymerization, droplet nucleation is the key factor to ensure the production of polymer particles with a desired composition. The influence of the initiation on droplet nucleation is conflicting and it has not been completely considered. The result of employing different initiator systems on the nucleation mechanism and kinetics in the polymerization of stable styrene/polystyrene miniemulsions with varied droplet size is discussed here. The initiation systems employed provide all combinations between the phase (aqueous or organic) where initiation mainly occurs and the phase affinity of the produced radicals. Latexes with different contributions of droplet nucleation were synthesized according to the employed initiation system and the droplet size of the miniemulsion. The results presented here could be used as a guide for choosing the initiation system to achieve the required contribution of droplet nucleation.
TL;DR: It is possible to conclude that ammonium nitrate is an interesting alternate nitrogen source for the cultivation of A. platensis in a fed-batch process and could be used for other photosynthetic microorganisms.
Abstract: NH4NO3 simultaneously provides a readily assimilable nitrogen source (ammonia) and a reserve of nitrogen (nitrate), allowing for an increase in Arthrospira platensis biomass production while reducing the cost of the cultivation medium. In this study, a 22plus star central composite experimental design combined with response surface methodology was employed to analyze the influence of light intensity (I) and the total amount of added NH4NO3 (Mt) on a bench-scale tubular photobioreactor for fed-batch cultures. The maximum cell concentration (Xm), cell productivity (PX) and biomass yield on nitrogen (YX/N) were evaluated, as were the protein and lipid contents. Under optimized conditions (I = 148 μmol·photons·m-2·s-1 and Mt = 9.7 mM NH4NO3), Xm = 4710 ±34.4 mg·L-1, PX = 478.9 ±3.8 mg·L-1·d-1 and YX/N = 15.87 ±0.13 mg·mg-1 were obtained. The best conditions for protein content in the biomass (63.2%) were not the same as those that maximized cell growth (I = 180 μmol·photons·m-2·s-1 and Mt = 22.5 mM NH4NO3). Based on these results, it is possible to conclude that ammonium nitrate is an interesting alternate nitrogen source for the cultivation of A. platensisin a fed-batch process and could be used for other photosynthetic microorganisms.
TL;DR: In this paper, the authors investigated the interfacial energy involved in the production of water-in-oil (W/O) emulsions composed of water and a Brazilian heavy crude oil.
Abstract: The aim of this study was to investigate the interfacial energy involved in the production of water-in-oil (W/O) emulsions composed of water and a Brazilian heavy crude oil. For such purpose an experimental set-up was developed to measure the different energy terms involved in the emulsification process. W/O emulsions containing different water volume fractions (0.1, 0.25 and 0.4) were prepared in a batch calorimeter by using a high-shear rotating homogenizer at two distinct rotation speeds (14000 and 22000 rpm). The results showed that the energy dissipated as heat represented around 80% of the energy transferred to the emulsion, while around 20% contributed to the internal energy. Only a very small fraction of the energy (0.02 - 0.06%) was stored in the water-oil interface. The results demonstrated that the high energy dissipation contributes to the kinetic stability of the W/O emulsions.
TL;DR: In this paper, a numerical modeling and simulation based on the available knowledge of SCR kinetics for prediction of NO conversion over a V2O3/TiO3 catalyst through a catalytic filter medium and honeycomb reactor is presented.
Abstract: The present study addresses a numerical modeling and simulation based on the available knowledge of SCR kinetics for prediction of NO conversion over a V2O3/TiO3 catalyst through a catalytic filter medium and honeycomb reactor. After introducing the NH3-SCR system with specific operational criteria, a reactor model was developed to evaluate the effect of various operating parameters such as flue gas temperature, velocity, NH3/NO molar ratio, etc., on the SCR process. Computational investigations were performed based on the proposed model and optimum operational conditions were identified. Simulation results indicate that SCR performance is substantially under the effects of reactant concentration and operating temperature, so that the concentration of unreacted ammonia emitted from reactor discharge (ammonia slip) increases significantly at NH3/NO ratios of more than 1.14 and operating temperatures less than 360 oC and 300 oC, respectively, in the catalytic filter medium and honeycomb reactor. The results also show that there are three sections in NO conversion variation versus changing temperature and the required conversion with a maximum of almost 87% and low level of ammonia slip can be achieved at the NH3/NO ratio of 1 and temperature range of 240–360 oC in both reactors.
TL;DR: In this paper, the mutual solubilities of sets of ionic liquids (n = 4, 8, 12), [C4PY] [TF2N], [C8MIM] [OTF]) and organic compounds (heptane, o-xylene, toluene, or water) are investigated.
Abstract: In this work, the mutual solubilities of sets of ionic liquids ([CnMIM] [TF2N] (n = 4, 8, 12), [C4PY] [TF2N], [C8MIM] [OTF]) and organic compounds (heptane, o-xylene, toluene, or water) are investigated. The experimental data measured for these systems were used to adjust the binary interaction parameters between their components for the Non-Random Two Liquid (NRTL) model. The results showed that the solubility increased with temperature, with high hygroscopicity (10-1 in terms of mole fraction) of the ILs, low interactions with aliphatic hydrocarbons, high interactions with aromatic hydrocarbons and the presence of a lower critical solution temperature (LCST). In addition, this study is the first to show that [C12MIM] [TF2N] is completely soluble in toluene and ortho-xylene between 273.15 and 373.15 K at 1 bar. The average deviations related to the mole fraction between the experimental and calculated values by the NRTL were less than 2.4%.
TL;DR: The experimental design contributed to adjust the concentrations of minerals and urea of the culture media for cellulase and xylanase production by P. echinulatum, avoiding waste of components in the medium.
Abstract: Penicillium echinulatum S1M29 is a mutant with cellulase and xylanase production comparable to the most studied microorganisms in the literature. However, its potential to produce these enzymes has not been fully investigated. This study aimed at optimizing salt and urea concentrations in the mineral solution, employing the response surface methodology. A 25-1 Fractional Factorial Design and a 23 Central Composite Design were applied to elucidate the effect of salts and urea in enzyme production. Lower concentrations of KH2PO4 (2.0 g.L-1), (NH4)2SO4 (1.4 g.L-1), MgSO4.7H2O (0.375 g.L-1) and CaCl2 (0.375 g.L-1) were most suitable for the production of all enzymes evaluated. Nevertheless, higher concentrations of urea (0.525 g.L-1) gave the best results for cellulase and xylanase production. The maximum FPase (1,5 U.m.L-1), endoglucanase (7,2 U.m.L-1), xylanase (30,5 U.m.L-1) and β-glucosidase (4,0 U.m.L-1) activities obtained with the planned medium were, respectively, 87, 16, 17 and 21% higher when compared to standard medium. The experimental design contributed to adjust the concentrations of minerals and urea of the culture media for cellulase and xylanase production by P. echinulatum, avoiding waste of components in the medium.
TL;DR: In this article, an AnSBBR (anaerobic sequencing batch reactor containing biomass immobilized on an inert support) with liquid phase recirculation was used to produce biohydrogen.
Abstract: An AnSBBR (anaerobic sequencing batch reactor containing biomass immobilized on an inert support) with liquid phase recirculation, containing a 3.5 L working volume, treated 1.5 L of cheese whey wastewater in 3 and 4 h cycles at 30 oC to produce biohydrogen. From startup the bioreactor presented process instability. To overcome this problem the following measures were taken, however without success: adaptation of the biomass with uncontaminated easily degradable substrates, pH control at very low levels, and a different form of inoculation (natural fermentation of the feed medium). The problem was solved by cooling the feed medium to 4 oC to prevent acidification in the storage container, by eliminating nutrient supplementation to prevent possible formation of H2S by sulfate-reducing bacteria and by periodic washing of the support material to improve the food/microorganism ratio. Hence, stable hydrogen production could be achieved with minimal presence of methane (36% H2; 62% CO2; 2% CH4) and the AnSBBR fed with cheese whey (influent concentration of 4070 mgCOD.L-1 and 3240 mgCarbohydrate.L-1 and applied volumetric organic loading of 14.6 gCOD.L-1.d-1) presented improved productivity and yield indicators compared to pure lactose and other reactor configurations, reaching values of 420 NmLH2.L-1.d-1 and 0.60 molH2.molCarbohydrate-1 in the steady-state phase (conversions of carbohydrates and COD were 98% and 30%, respectively).
TL;DR: In this paper, the authors used a thermodynamic analysis to find operational conditions that favor the production of hydrogen from steam and oxidative reforming of liquefied petroleum gas (LPG).
Abstract: The objective of this paper was to use a thermodynamic analysis to find operational conditions that favor the production of hydrogen from steam and oxidative reforming of liquefied petroleum gas (LPG). We also analyzed the performance of a catalyst precursor, LaNiO3, in order to compare the performance of the obtained catalyst with the thermodynamic equilibrium predictions. The results showed that it is possible to produce high concentrations of hydrogen from LPG reforming. The gradual increase of temperature and the use of high water concentrations decrease the production of coke and increase the formation of H2. The reaction of oxidative reforming of LPG was more suitable for the production of hydrogen and lower coke formation. Furthermore the use of an excess of water (H2O/LPG =7.0) and intermediate temperatures (973 K) are the most suitable conditions for the process.
TL;DR: In this paper, a mathematical model was formulated to predict the evolution of the effluent concentrations and showed similar evolutions for yields of hydrogen and carbon monoxide at temperatures below 823 K for operations with and without the hydrogen permeation.
Abstract: Syngas and hydrogen production by methane reforming of a biogas (CH4/CO2 = 2.85) using carbon dioxide was evaluated in a fixed bed reactor with a Pd-Ag membrane in the presence of a nickel catalyst (Ni 3.31% weight)/γ-Al2O3) at 773 K, 823 K, and 873 K and 1.01×105 Pa. Operation with hydrogen permeation at 873 K increased the methane conversion to approximately 83% and doubled the hydrogen yield relative to operation without hydrogen permeation. A mathematical model was formulated to predict the evolution of the effluent concentrations. Predictions based on the model showed similar evolutions for yields of hydrogen and carbon monoxide at temperatures below 823 K for operations with and without the hydrogen permeation. The hydrogen yield reached approximately 21% at 823 K and 47% at 873 K under hydrogen permeation conditions.