Showing papers in "Chemical Engineering and Processing in 2013"

Molten salts database for energy applications

Abstract: The growing interest in energy applications of molten salts is justified by several of their properties. Their possibilities of usage as a coolant, heat transfer fluid or heat storage substrate, require thermo-hydrodynamic refined calculations. Many researchers are using simulation techniques, such as Computational Fluid Dynamics (CFD) for their projects or conceptual designs. The aim of this work is providing a review of basic properties (density, viscosity, thermal conductivity and heat capacity) of the most common and referred salt mixtures. After checking data, tabulated and graphical outputs are given in order to offer the most suitable available values to be used as input parameters for other calculations or simulations. The reviewed values show a general scattering in characterization, mainly in thermal properties. This disagreement suggests that, in several cases, new studies must be started (and even new measurement techniques should be developed) to obtain accurate values.

Review: Microstructured reactors for distributed and renewable production of fuels and electrical energy

Abstract: The current paper provides an overview of recent and past research activities in the field of microreactors for energy related topics. The main research efforts in this field are currently focussing on fuel processing as hydrogen source, mostly for distributed consumption through fuel cells. Catalyst development, reactor design and testing for reforming and removal of carbon monoxide through water-gas shift, preferential oxidation, selective methanation and membrane separation are therefore under investigation. An increasing number of integrated complete micro fuel processors has been developed for a large variety of fuels, assisted by static and dynamic simulation of these systems. The synthesis of liquid fuels is another emerging topic, namely Fischer-Tropsch synthesis, methanol and dimethylether production from synthesis gas and biodiesel production.

Microbubble generation and microbubble-aided transport process intensification—A state-of-the-art report

Abstract: This article aims to provide a state-of-the-art assessment of the research work carried out so far in microbubble-aided transport processes The different methods of microbubble generation and the properties of microbubble have been reported in this article The different components that constitute the microbubble are also discussed The characteristics of microbubble are pointed out The measuring methods of zeta potential in microbubble system are described This article provides an update of important research works in the microbubble technology This article also reports the important future research scope and their significance in the microbubble flow system For researchers, this article may be useful for further research in microbubble technology

Vacuum membrane distillation processes for aqueous solution treatment—A review

Abstract: The current applications of vacuum membrane distillation (VMD) process for various industrial aqueous solutions have been thoroughly reviewed. The applications of VMD can be grouped into three major processes: the single component transport process, the binary component transport process and the multicomponent transport process. The porous and hydrophobic membrane in the VMD system serves as a physical support for the liquid–gas interface and does not allow one of the phases to disperse into the other. The membrane provides an efficient separator for the phase-change process. The use of the correct membrane can offer a high production rate and a high separation factor at low temperatures. VMD, an alternative separation technology with applications in desalination, concentration, organic extraction and dissolved gas removal, can compete with conventional liquid–gas separation systems. The present paper critically reviewed VMD technology; the important components of the scope of this review included applications and processes, membrane modules, heat and mass transfer, model development, membrane, process conditions, fouling, energy consumption and production cost. Finally, the potential for future research as a requisite for VMD industrialisation was suggested.

Optimization of electrocoagulation process for removal of an azo dye using response surface methodology and investigation on the occurrence of destructive side reactions

Abstract: The optimization and modeling of the electrocoagulation process which conducted by means of iron (EC-Fe) and aluminum (EC-Al) anodes, in the removal of C.I. Reactive Red 43 were performed through the response surface methodology (RSM). Moreover, the occurrence of possible destructive reactions during both EC-Fe and EC-Al processes was investigated using UV–Vis spectrometry, total organic carbon (TOC) and GC–MS analyses. The electrocoagulation experiments were carried out in a monopolar batch reactor using two anodes and two cathodes in parallel connections. Current density, time, pH and chloride concentration were considered as input variables for RSM. The analysis of variance revealed a high coefficient of determination ( R EC-Fe 2 = 0.981 and R EC-Al 2 = 0.934 ) between experimental removal efficiency and predicted one by RSM developed models. The optimum conditions proposed by RSM to reach the maximum RR43 removal through the EC-Fe were different from the ones proposed for the EC-Al. At the optimum conditions, the removal efficiency of dye was more than 99% for both processes, whereas 90.58% and 98.37% of initial TOC concentration decreased during EC-Fe and EC-Al processes, respectively. The analyses results confirmed that beside sweep flocculation mechanism, known as the main removal mechanism, the degradation of dye was occurred during EC-Fe as a minor pathway.

Comparison of effectiveness of acoustic and hydrodynamic cavitation in combined treatment schemes for degradation of dye wastewaters

Abstract: Cavitation has shown promising applications but individually it cannot prove to be an energy efficient approach for wastewater treatment. The present study reports the use of combined treatment strategies based on cavitation and different oxidizing agents (H 2 O 2 , Na 2 S 2 O 8 and NaOCl). Decolorization of two biorefractory dye pollutants viz. orange acid-II (OA-II) and brilliant green (BG) has been investigated as model systems for comparison of the effectiveness of cavitating conditions generated by acoustic and hydrodynamic modes. The optimum conditions for temperature, pH and power dissipation in the case of acoustic cavitation and inlet pressure in the case of hydrodynamic cavitation have been established initially. At the optimum operating conditions, the effect of combination of different oxidizing agents has been examined with an objective of obtaining the maximum decolorization. Basic extent of decolorization due to the use of oxidizing agents has also been quantified by performing experiments in the absence of cavitating conditions. The obtained results for cavitational yields indicate that the decolorization is most efficient for the combination of hydrodynamic cavitation and chemical oxidation as compared to chemical oxidation and acoustic cavitation based combination for both the dye effluents.

Slot-die processing of lithium-ion battery electrodes—Coating window characterization

Abstract: Slot-die coating is actually the most used coating method for the manufacturing of lithium-ion battery electrodes. An easy way of reducing production costs is to increase the line capacity. Thus, the relatively high-viscous slurries are coated at continuously increasing velocities. Facing these higher and higher velocities, the main processing challenge is to ensure that the surface quality stays constant. Therefore we investigated coating of high-viscous anode slurries consisting of large graphite particles. Systematically detected conditions for which coating defects occurred were discussed and compared with different theoretical limits for stable coating conditions. Thereby the uniformity of the stable wet film was analyzed and logged with a two dimensional laser sensor system. Even though the detected break-up lines are, in some regions, congruent with the applied viscocapillary models, the appearing coating defects are not as expected in the literature. Furthermore, large particles and agglomerations may provoke an additional film break-up at small film thicknesses regardless of the coating speed. For stable conditions the roughness of the film increases when the dimensionless gap width increases.

Extraction of ursolic acid from Ocimum sanctum by ultrasound: Process intensification and kinetic studies

Abstract: The present work describes the application of ultrasound for the intensification of ursolic acid (UA) extraction from Ocimum sanctum (OS). The different process parameters such as extraction time, solid to solvent ratio, extraction temperature, ultrasound power and frequency have been optimized based on the maximum extraction yield. The maximum yield 16.47 mg UA/g of OS was obtained at optimum extraction conditions (extraction time 12 min, solid to solvent ratio 1:30, temperature 45 °C and frequency of 25 kHz). Effect of 25 kHz and 40 kHz has been observed at different power dissipation. The combined effect of frequency and ultrasound power gives a better extraction yield while temperature has no significant effect on extraction. The yield obtained with ultrasound-assisted extraction (UAE) has been compared with batch and soxhlet extraction of UA. This research clearly shows that the UAE method is quite better than conventional extraction as it effectively reduces the extraction time of UA to just 12 min without deterioration. Further, the kinetics of the extraction is investigated by the Peleg's model. The extraction rate constant, initial extraction rate and equilibrium concentration for all experimental conditions have been predicted. The mathematical model applied showed a good agreement with the experimental results.

A review on combustion synthesis intensification by means of microwave energy

Abstract: Combustion synthesis (CS) is a materials manufacturing technique, which gained increased attention by both academia and industries, due to its intrinsic energy saving characteristics and high purity of the products. Energy requirements for CS are limited to the ignition step, since the desired products are obtained by using the heat generated by exothermic reactions occurring between the reactants. CS has been here addressed from a process intensification perspective, since CS characteristics perfectly fit into several process intensification definitions, aims and approaches. Particular attention has been dedicated to the use of microwaves as energy source for CS, and the benefits deriving from the combination of these two techniques have been reviewed. The doubtless better energy transfer efficiency of microwaves, with respect to conventional heating techniques, arising from the direct interaction of the electromagnetic energy with the reactants, contributes to further intensify both solid state and solution CS processes. Moreover, microwaves peculiarities, such as their selective and volumetric nature, together with their energy transfer nature, open new attractive opportunities for CS in different fields of materials science, like joining and advanced protective coatings. Innovative strategies of microwaves-ignited and/or sustained CS for the process intensification of advanced materials manufacturing are proposed as well.

Scalable high-power ultrasonic technology for the production of translucent nanoemulsions

Abstract: Oil-in-water nanoemulsions are widely used in cosmetics, pharmaceutical, food, agricultural and other industries as delivery systems for active lipophilic compounds and drugs. Translucent nanoemulsions are especially attractive because their extremely small droplet sizes lead to long-term stability, improve absorption by the skin and enable the delivery of exceptionally high concentrations of active substances. High-power ultrasound has previously been successfully used to produce translucent nanoemulsions on laboratory scale. However, due to limitations of conventional ultrasonic liquid processing technology, scaling up has not been possible, restricting industrial implementation of this process. In this study, ultrasonic production of translucent oil-in-water nanoemulsions was optimized on a laboratory scale and then directly scaled up. The ultrasonic amplitude played a significant role in this process, and was determined to be optimal near 90 μm peak-to-peak. Barbell Horn Ultrasonic Technology was employed to scale up the process by a factor of 10 without reducing the ultrasonic amplitude or compromising the product quality. The scale-up procedure is described in detail. Further scale-up by a factor of five is theoretically shown to be possible, potentially making high-power ultrasound an important industrial method for producing nanoemulsions.

Comparison of large scale coating techniques for organic and hybrid films in polymer based solar cells

Abstract: Polymer based solar cells (PSC) can be manufactured in a continuous roll to roll process as a low cost regenerative energy source. Coating ink properties and film thicknesses of 30–200 nm are challenging with respect to the manufacturing process, which itself has an important impact on film properties and cell efficiencies. In this paper we compare the large area coating methods: knife coating, slot-die coating, and spray coating with laboratory spin coating. Properties of coating inks and a viscosity model for commercial PEDOT:PSS types are discussed. The significantly smaller viscosity to surface tension ratio, of typical coating inks for PSC compared to conventional coating inks, causes a different behavior during the coating process. Wet film thickness, homogeneity, and process stability and their dependence on process parameters are addressed for each coating method. Hole-conductive and photoactive layers, consisting of polymer-fullerene and polymer-nanoparticle blends, are then compared with respect to homogeneity, AFM topography and absorption spectra. First results indicate that the coating method itself has an impact on polymer-fullerene film morphology and opto-electric properties.

A batch LED reactor for the photocatalytic degradation of phenol

Abstract: Photocatalytic degradation of phenol by titanium dioxide illuminated by one light emitting diode (LED) in a batch photocatalytic reactor is reported in this paper. The effect of catalyst loading, catalyst type, phenol–hydrogen peroxide ratio, pH, initial phenol concentration and irradiance by applying pulse width modulation (PWM) was studied. The effect of the beam width on photocatalytic degradation of phenol is also included in this paper as is the use of different type of reflectors outside the reactor. With both an LED beam width of 120° and optimal chemical conditions of 10 ppm phenol concentration with a hydrogen peroxide–phenol molar ratio of 100 and pH of 4.8, a degradation rate of 42% was achieved after 4 h. Decreasing the beam width to 40° raised degradation to 87%. In order to study the irradiance distribution and its effect on the reactor performance, experiments were conducted incorporating various catalysts loading, reactor heights and beam widths. The irradiance was measured for different amount of catalyst loading ranging from 0.17 to 1.8 g L −1 at different reactor heights. The results are compared with optimal catalyst loading measurement to assess the correlation between phenol degradation and irradiance distribution. The UV LED in combination with titanium dioxide is appropriate for water treatment to degrade organic pollutants at low concentration.

A novel process configuration for co-production of NGL and LNG with low energy requirement

Abstract: In this study a novel integrated process configuration for NGL/LNG production is introduced and analyzed. This configuration uses two mixed refrigerant cycles in order to supply the required refrigeration for production of both NGL and LNG. The results showed that not only liquefaction efficiency of the process is considerable (0.414 kWh/kg LNG) but also it can recover the ethane (from a rich typical feed gas (methane 75%, and heavier hydrocarbons 23%)) higher than 93.3%. Four multi stream heat exchangers were utilized, the composite curves of them shows that they have been designed optimally. These heat exchangers perform their role for both targets simultaneously due to the integration of the NGL and LNG processes. Even though this point increases their size, but the total capital costs of the plant decrease. This process can be used for large LNG plants in the natural gas refineries. It can also be said that the overall efficiency will be higher for the leaner feed gases.

Hydrodynamic cavitation as an efficient approach for intensification of synthesis of methyl esters from sustainable feedstock

Abstract: Investigations related to process intensification of synthesis of methyl esters from sustainable feedstock is gaining importance because of considerable energy requirements and higher reaction time in the conventional approach. The present work illustrates the use of hydrodynamic cavitation for intensification of methyl ester synthesis from the high acid value non-edible oil. Two-step synthesis of acid esterification followed by alkaline transesterification has been employed for obtaining the methyl esters. In first step, acid esterification is used to reduce the acid value of oil from 18.7 to less than 1.5 mg of oil/g of oil beyond which alkaline transesterification can be used without any problems of soap formation. The molar ratio and catalyst concentration have been optimized for the esterification and transesterification stages. The optimized molar ratios were 1:3 and 1:6 for esterification and transesterification respectively. Under optimized conditions, 92% conversion has been obtained in the transesterification stage. It has been established that due to the use of hydrodynamic cavitation, the energy requirement for the synthesis is significantly reduced as compared to the conventional approach. The novel route discussed in the present work provides a viable option and can be explored easily for the industrial scale of operations.

Bio-ethanol steam reforming and autothermal reforming in 3-μm channels coated with RhPd/CeO2 for hydrogen generation

Abstract: A silicon micromonolith of 7 mm diameter and 0.2 mm length containing 1.5 million regular channels with a diameter of 3.3 μm was used for obtaining hydrogen through ethanol or bio-ethanol steam reforming (ESR) and oxidative steam reforming (OSR). The microchannels were coated with RhPd/CeO 2 catalyst by a two-step method. First a CeO 2 layer of ca. 100 nm thickness was deposited from cerium methoxyethoxide over a SiO 2 layer, which was previously grown over the silicon microchannels by oxidation. Then, noble metals were grafted over the CeO 2 support from chloride precursors. The unit was successfully tested for hydrogen production, achieving hydrogen rates of 180 L H 2 c m R − 3 for the steam reforming of bio-ethanol at 873 K, S/C = 2 and 0.009 s contact time. Reaction yields of 3.8 and 3.7 mol hydrogen generated per mol ethanol in feed were measured for ESR and OSR, respectively. A performance comparison was performed with a conventional cordierite monolith with the same catalyst formulation. Results show for the silicon microreactor an outstanding improvement of the specific hydrogen production rate, operating at considerably reduced residence times, due to the increase in contact area per unit volume.

Ultrasound assisted synthesis of polythiophene/SnO2 hybrid nanolatex particles for LPG sensing

Abstract: Polythiophene (PTP) coated SnO 2 nano-hybrid particles have been synthesized using an ultrasound assisted in situ oxidative polymerization of thiophene monomers. Reference experiments have also been performed in the absence of ultrasound to clearly illustrate the effect of ultrasonic irradiations. FTIR results show broadening and shifting of peaks toward lower wave numbers, suggesting better conjugation and chemical interactions between PTP and SnO 2 particles. Due to strong synergetic interaction between the SnO 2 nanoparticles and polythiophene, this hybrid nanocomposite has the potential application as chemical sensors. It has been observed that PTP/SnO 2 hybrid sensors could detect liquefied petroleum gas (LPG) with high sensitivity at room temperature. PTP/SnO 2 hybrid composite containing 20 wt% SnO 2 showed the maximum sensitivity at room temperature. The sensing mechanism of PTP/SnO 2 hybrid nanocomposites to LPG was mainly attributed to the effects of p–n heterojunction between PTP and SnO 2 .

Process intensification in lactic acid production by three stage membrane integrated hybrid reactor system

Abstract: l (+) lactic acid was directly produced in a three-stage membrane-integrated hybrid reactor system starting with a cheap, renewable and clean carbon source. Provision of flat sheet cross flow membrane modules for microfiltration and nanofiltration permitted selective production of l (+) lactic acid under high cell density with recycling of cells and unconverted sugars. This modular design ensured high yield (0.96 g g −1 ), productivity (12.4 g L −1 h −1 ), concentration (250 g L −1 ) and purity (95%) in a very simple, environmentally benign, compact and flexible plant configuration reflecting all the major characteristics of high process intensification. Such process intensification has been analysed for the first time in terms of space intensification, application flexibility, capacity flexibility, energy reduction parameter and cost advantage parameter. The value of space intensification parameter, energy reduction parameter and cost advantage parameter that were computed to be 3.33, 0.022 and 0.35 respectively indicated high degree of process intensification in such a novel and green production scheme.

Bubbling fluidization of biomass and sand binary mixtures: Minimum fluidization velocity and particle segregation

Abstract: Understanding the minimum fluidization velocity of biomass and sand mixtures is fundamental to ensuring the optimal performance of fluidized beds in a thermo-conversional process, such as fast pyrolysis. The present work aimed to determine the minimum fluidization velocity of binary mixtures using the characteristic diagram of pressure drop in the bed and to develop an experimental correlation for the minimum fluidization velocity of biomass and sand mixtures. Three types of biomass (sweet sorghum bagasse, waste tobacco and soybean hulls) and four sands with different sizes were investigated. The results showed that the fluid dynamic behavior of binary mixtures is directly related to the biomass size and shape. For sweet sorghum bagasse (more irregular particles), higher biomass percentages led to lower minimum fluidization velocities, which differed from the behaviors observed for waste tobacco and soybean hulls. The diameter ratio inert/biomass effectively influenced the segregation, with a higher ratio causing more pronounced bed segregation. A good fluidization regime (with little segregation) for biomass and sand mixtures was obtained using the smallest sand ( d 50 = 0.35). Considering the studied operating conditions, the proposed correlation can be used satisfactorily to predict the minimum fluidization velocities for mixtures of biomass and sand in fluidized beds.

Dip coating with colloids and evaporation

Abstract: We investigate the coating of a glass plate with silica colloids by a dip coating method in presence of evaporation. We show experimentally that the deposed quantity plotted versus plate velocity V exhibits a minimum, in agreement with a simple argument developed by us in a previous, theoretical paper. This minimum corresponds to a crossover between the well-known Landau–Levich regime observed at higher plate velocity and a less well-known regime at lower plate velocity where the deposit is formed directly at the contact line. This very general result is consistent with experiments and calculations made by other teams with different compounds or under different drying geometries. Modifying our initial argument by taking into account the particle density gradient, we show that a simple modeling of each regime in terms of scaling laws is possible, the deposed mean thickness scaling respectively as V−1 and V2/3 in the lower and higher velocity limits.

Industrial applications of plasma, microwave and ultrasound techniques: Nitrogen-fixation and hydrogenation reactions

Abstract: The MAPSYN project (Microwave, Acoustic and Plasma assisted SYNtheses) aims at nitrogen-fixation reactions intensified by plasma catalysis and selective hydrogenations intensified by microwaves, possibly assisted by ultrasound. Energy efficiency is the key motif of the project and the call of the European Union behind (NMP.2012.3.0-1; highly efficient chemical syntheses using alternative energy forms). The material (catalysis) and process innovations given in the literature for the two demonstration examples (of the project) are reviewed and added by the project's own ones derived from the latest state of the art. From there still a gap to industrialization needs to be closed which needs innovation as well on the level of process control and plant operation, finally opening gates to new business models (distributed production and modular plant-numbering up instead of scale-up). Such systemic solution shall be developed under the supervision of energy and cost analysis as well as life-cycle analysis to ensure following a holistic approach. This demands for a new science management not focusing only on the key innovation, but as well as on other assisting enabling technologies needed and for the systemic vision with plant view and process control – all centered around industrial reaction equipment.

Kinetic study of catalytic esterification of acrylic acid with butanol catalyzed by different ion exchange resins

Abstract: The esterification of acrylic acid and n-butanol catalyzed by three different ion exchange resins, Amberlyst 15, Amberlyst 131 and Dowex 50Wx-400 was studied. Amberlyst 131 was found to be more efficient catalyst giving the maximum conversion of acrylic acid. The effects of temperature, molar ratio of alcohol to acid, stirrer speed and catalyst loading on the reaction rate were investigated. The chemical equilibrium constants were obtained experimentally and theoretically from thermodynamic properties. The experimental data were tested with four different reaction mechanisms according to adsorption status of reactants. The activity coefficients were calculated using UNIQUAC method to account for the non-ideal thermodynamic behavior. The activation energy was found to be 57.4 kJ/mol according to the LHHW model which correlates the experimental data with minimum error.

Palm oil transesterification in sub- and supercritical methanol with heterogeneous base catalyst

Abstract: An environmentally benign process for the production of methyl ester using γ-alumina supported heterogeneous base catalyst in sub- and supercritical methanol has been developed. The production of methyl ester in refluxed methanol conventionally utilized double promoted γ-alumina heterogeneous base catalyst (CaO/KI/γ-alumina); however, this process requires a large amount of catalyst and a long reaction time to produce a high yield of methyl ester. This study carries out methyl ester production in sub- and supercritical methanol with the introduction of an optimized catalyst used in the previous work for the purpose of improving the process and enhancing efficiency. CaO/KI/γ-Al 2 O 3 catalyst was prepared by precipitation and impregnation methods. The effects of catalyst amount, reaction temperature, reaction time, and the ratio of oil to methanol on the yield of biodiesel ester were studied. The reaction was carried out in a batch reactor (8.8 ml capacity, stainless steel, AKICO, Japan). Results show that the use of CaO/KI/γ-Al 2 O 3 catalyst effectively reduces both reaction time and required catalyst amount. The optimum process conditions were at a temperature of 290 °C, ratio of oil to methanol of 1:24, and a catalyst amount of 3% over 60 min of reaction time. The highest yield of biodiesel obtained under these optimum conditions was almost 95%.

Process intensification of uniform loading of SnO2 nanoparticles on graphene oxide nanosheets using a novel ultrasound assisted in situ chemical precipitation method

Abstract: In this paper, a novel ultrasound assisted, solution-based chemical synthesis method for the preparation of SnO 2 –graphene nanocomposite is presented. Graphene oxide (GO) was prepared by the modified Hummers–Offeman method in presence of ultrasonic irradiation. Further loading of SnO 2 on GO was carried out with an ultrasound assisted solution-based synthesis route. The prepared GO and SnO 2 –graphene nanocomposite were characterized by XRD, TEM, FTIR spectra, TGA and DTA analysis in order to confirm the formation of graphene–SnO 2 nanocomposite. TEM analysis of ultrasonically prepared graphene–SnO 2 composite shows the uniform and fine loading of SnO 2 particles (3–5 nm) on graphene nanosheets. However agglomerated morphology was observed in case of conventionally prepared graphene–SnO 2 composite. The cavitational effects generated due to the ultrasonic irradiations during the synthesis of graphene–SnO 2 composite improve the fine and uniform loading of SnO 2 on graphene nanosheets by oxidation–reduction reaction between GO and SnCl 2 ·2H 2 O compared to conventional synthesis methods. The formed material was used for the preparation of anode in lithium ion batteries and its electrochemical performance was characterized by cyclic voltammetry and charge/discharge cycles. It is found that the capacity of SnO 2 –graphene nanocomposite based Li-battery is stable for around 120 cycles, and the battery could repeat stable charge–discharge reaction.

A study on developing aviation biofuel for the Tropics: Production process—Experimental and theoretical evaluation of their blends with fossil kerosene

Abstract: In the present work, the production process of bio-jet paraffins is appropriately proposed according to the conditions of the socioeconomic situations, the current technologies of biofuel production and the available feedstock sources for the tropical countries. The blending process of bio-kerosene which is a mixture of bio-jet paraffins and fossil kerosene is also displayed. The two prototypes of bio-paraffins (Bio-P1 and Bio-JP2), which were manufactured in Indonesia following the proposed production process, are used for making bio-kerosenes in current study. The theoretical and experimental investigations have been carried out to evaluate and identify the critical properties of bio-kerosenes: distillations, freezing point, lower heating value, density, flash point and viscosity to ensure ASTM criteria of jet fuel. The results show it can be blended directly 5% volume of Bio-P1 or 10% volume of Bio-JP2 to commercial Jet A-1 for powering aviation gas turbine engines without redesigning fuel system or fuel supply infrastructure. The use of these bio-paraffins not only reduces CO 2 lifecycle but also significantly decreases emissions of sulfur compounds (SO x ). With preliminary achievements of this work, it is no doubt about the feasibility of developing aviation alternative fuels according to the proposed production process for the tropical countries.

Successive processes for purification and extraction of phosphoric acid produced by wet process

Abstract: Different technologies were tested for purification of phosphoric acid produced by the wet process Iliminite clay was found suitable for removal of humic acids and suspended materials from crude phosphoric acid Minimizing of ferric ions from phosphoric acid was carried out using silica, while removal of fluoride was proceeded by addition of carbonate salt Isoamyl alcohol was used for extraction of P 2 O 5 giving value of 785% Using McCabe–Thiele diagram, the number of stages for complete extraction of P 2 O 5 was predicted as two stages Warm distilled water had a good efficiency for stripping of P 2 O 5 Flow chart for sequential treatment process and extraction was constructed

Control structure selection for three-product Petlyuk (dividing-wall) column

Abstract: This paper deals with selecting control structures for a three-product Petlyuk (dividing-wall) column with an objective to achieve desired product purities with minimum use of energy (V). We consider four alternate control structures with and without the vapor split as a degree of freedom. This work also demonstrates the usefulness of the graphical V min diagram to visualize minimum boilup requirement and choose the appropriate control structure.

The effect of sparger geometry on gas holdup and regime transition points in a bubble column equipped with perforated plate spargers

Abstract: This paper investigates the effect of sparger geometry on flow regime of a bubble column. The experiments presented in this study were performed under atmospheric pressure with water/air in a cylindrical Plexiglas® column of 33.0 cm i.d. and 3.0 m height. Three different perforated plate spargers were employed. Hole diameter was varied in the range of 1–3 mm, while the free area was 1.0%. The theory of linear stability is used for the prediction of regime transitions in the bubble column and a comparison has been presented between the predictions and the experimental observations. A good agreement between the predictions and the experimental values of transition gas holdup has been obtained. In addition, the data from the literature has been analyzed. Experimental values of transition gas holdups and predictions by the theory of linear stability have been compared with those of literature. A correlation based on dimensionless numbers (Archimedes, Froude, Eotvos and Weber) and the group (do/DC) for the prediction of gas holdup in homogeneous regime is proposed. The average error between the correlation predictions and experimental values remains under ±10%. The proposed correlation is compared with the published data and found to be in fairly good agreement.

Intensification of biodiesel production from vegetable oils using ultrasonic-assisted process: Optimization and kinetic

Abstract: Intensification of biodiesel production process using low frequency ultrasonic irradiation (20 kHz, 200 W) is elucidated in this study. Effects of five process variables in an ultrasonic-assisted reactor catalyzed by SrO through transesterification of vegetable oils are investigated. RSM was employed and the optimum conditions were at an ultrasonic pulse on of 9 s followed by 2 s of pulse off within a reaction time of 30.7 min. The optimum ultrasonic power was found to be 130 W using an oil amount of 52 g ( R 2 = 0.97). The model was applicable to different types of oil with errors less than 10%. FFA content was responsible for the different yields obtained with different oils. Three steps of the transesterification process were measured to obtain the kinetic study. The results revealed that the reaction followed a second-order kinetic. The activation energies varied between 70.63 kJ/mol and 136.93 kJ/mol showing relatively high coefficient of determinations.

Fabrication and testing of a planar microstructured concept module with integrated palladium membranes

Abstract: A planar microstructured hydrogen separation module has been fabricated to study the hydrogen permeation through free-standing palladium-based membranes (Pd, PdCu and PdAg) with minimal influence by concentration polarization. The membranes were laser-welded directly between two face-to-face arranged stainless-steel sheets with 10 microchannels each (width × depth × length of the channels: 500 μm × 300 μm × 2 cm). Single gas hydrogen and mixed gas permeation experiments (H 2 /N 2 ) were conducted between 300 and 400 °C. The permeabilities and activation energies of the membranes in this temperature range were calculated. The 12.5 μm thick membrane was successfully tested up to 650 kPa, indicating that the microchannel plates provide a good mechanical support even for very thin membranes. However, settling of the film into the microchannels on the permeate side was observed due to the overpressure on the retentate side suggesting even finer channels and eventually the use of an additional porous support for very high differential pressure. The concentration polarization effects in the membrane module were evaluated in terms of the film effectiveness factor η which is a familiar concept from heterogeneous catalysis. It could be shown that the microchannel configuration effectively decreases concentration polarization.

A one-step electrochlorination/electroflotation process for the treatment of heavy metals wastewater in presence of EDTA

Abstract: This study demonstrated the feasibility of simultaneous removal of heavy metals and EDTA in an electrolytic undivided cell equipped with Ti/RuO 2 as anode and stainless steel as cathode. In absence of EDTA, results show that nickel and copper removal by EF process is pH sensitive. In addition, nickel and copper may be substantially removed by EF. Removal efficiencies were 99.6% and 97%, respectively. In presence of EDTA, the metal removal by the EF process was inhibited. The inhibition rate was found to be dependent on EDTA/metal molar ratio. A one-step process, involving the combination of two techniques electrochlorination (EC) and electroflotation (EF), was set thanks to chloride addition. In situ generated active chlorine allowed the decomplexation of M-EDTA. Then, free metal ions were removed by precipitating and subsequent floating to the surface by rising electrogenerated bubbles. The obtained results revealed that, with 0.6 EDTA/metal molar ratio, removal efficiencies were 77% and 78% for nickel and EDTA, respectively, in the case of nickel–EDTA solutions. Removal efficiencies were 89% and 96% for copper and EDTA, respectively, in the case of copper–EDTA solutions. Furthermore, heavy metal removal efficiency by the combined process showed to be affected by chloride content and current intensity.