International Journal of Chemical Engineering The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Synthesis of CuNi/C and CuNi/-Al2O3 Catalysts for the Reverse Water Gas Shift Reaction Sun, 22 Mar 2015 13:29:54 +0000 A new polyol synthesis method is described in which CuNi nanoparticles of different Cu/Ni atomic ratios were supported on both carbon and gamma-alumina and compared with Pt catalysts using the reverse water gas shift, RWGS, reaction. All catalysts were highly selective for CO formation. The concentration of CH4 was less than the detection limit. Cu was the most abundant metal on the CuNi alloy surfaces, as determined by X-ray photoelectron spectroscopy, XPS, measurements. Only one CuNi alloy catalyst, Cu50Ni50/C, appeared to be as thermally stable as the Pt/C catalysts. After three temperature cycles, from 400 to 700°C, the CO yield at 700°C obtained using the Cu50Ni50/C catalyst was comparable to that obtained using a Pt/C catalyst. Maxime Lortie, Rima Isaifan, Yun Liu, and Sander Mommers Copyright © 2015 Maxime Lortie et al. All rights reserved. Analysis of Process Variables via CFD to Evaluate the Performance of a FCC Riser Tue, 24 Feb 2015 14:19:28 +0000 Feedstock conversion and yield products are studied through a 3D model simulating the main reactor of the fluid catalytic cracking (FCC) process. Computational fluid dynamic (CFD) is used with Eulerian-Eulerian approach to predict the fluid catalytic cracking behavior. The model considers 12 lumps with catalyst deactivation by coke and poisoning by alkaline nitrides and polycyclic aromatic adsorption to estimate the kinetic behavior which, starting from a given feedstock, produces several cracking products. Different feedstock compositions are considered. The model is compared with sampling data at industrial operation conditions. The simulation model is able to represent accurately the products behavior for the different operating conditions considered. All the conditions considered were solved using a solver ANSYS CFX 14.0. The different operation process variables and hydrodynamic effects of the industrial riser of a fluid catalytic cracking (FCC) are evaluated. Predictions from the model are shown and comparison with experimental conversion and yields products are presented; recommendations are drawn to establish the conditions to obtain higher product yields in the industrial process. H. C. Alvarez-Castro, E. M. Matos, M. Mori, W. Martignoni, and R. Ocone Copyright © 2015 H. C. Alvarez-Castro et al. All rights reserved. Model-Based Control of a Continuous Coating Line for Proton Exchange Membrane Fuel Cell Electrode Assembly Sun, 18 Jan 2015 14:28:15 +0000 The most expensive component of a fuel cell is the membrane electrode assembly (MEA), which consists of an ionomer membrane coated with catalyst material. Best-performing MEAs are currently fabricated by depositing and drying liquid catalyst ink on the membrane; however, this process is limited to individual preparation by hand due to the membrane’s rapid water absorption that leads to shape deformation and coating defects. A continuous coating line can reduce the cost and time needed to fabricate the MEA, incentivizing the commercialization and widespread adoption of fuel cells. A pilot-scale membrane coating line was designed for such a task and is described in this paper. Accurate process control is necessary to prevent manufacturing defects from occurring in the coating line. A linear-quadratic-Gaussian (LQG) controller was developed based on a physics-based model of the coating process to optimally control the temperature and humidity of the drying zones. The process controller was implemented in the pilot-scale coating line proving effective in preventing defects. Vikram Devaraj, Luis Felipe Lopez, Joseph J. Beaman, and Serge Prudhomme Copyright © 2015 Vikram Devaraj et al. All rights reserved. Fluence Rate in UV Photoreactor for Disinfection of Water: Isotropically Radiating Cylinder Mon, 10 Nov 2014 14:04:37 +0000 The calculation of fluence rate in the photochemical reactor using ultraviolet (UV) radiation for disinfection of water for the case, when a cylinder of infinite length is used as a light source, has been considered. Such a cylinder is filled with an isotropically radiating medium. The dependence of the fluent rate on the diameter of the radiating cylinder has been analytically analyzed. The limiting case when the diameter of the radiating cylinder tends to zero has been considered and the notion of “effective interval” has been introduced. Based on this notion, the comparison of fluence rates for the cylinders of finite and infinite lengths has been performed. In the calculations of fluence rate, it is advisable to use the Chebyshev method for the operations of numerical integration. Roman Ilinsky and Andrey Ulyanov Copyright © 2014 Roman Ilinsky and Andrey Ulyanov. All rights reserved. Recent Trends in Integrated Biorefineries Development for Sustainable Production Sun, 09 Nov 2014 12:43:44 +0000 Diego T. Santos, Adriano V. Ensinas, Anuj K. Chandel, François Maréchal, and M. Angela A. Meireles Copyright © 2014 Diego T. Santos et al. All rights reserved. Optimization of Indium Recovery and Separation from LCD Waste by Solvent Extraction with Bis(2-ethylhexyl) Phosphate (D2EHPA) Sun, 28 Sep 2014 10:00:01 +0000 Indium tin oxide (ITO) is currently the choice of electrode material in liquid crystal displays (LCDs). D2EHPA is known to be an extractant that can be used to selectively recover indium from 1 M sulfuric acid. In order to optimize the extraction and separation of indium from LCD waste, the effects of pH, temperature, time, and extractant concentration on the distribution ratios of In(III) and the major impurities such as Al(III), Cu(II), Fe(III), and Zn(II) were investigated. Metal concentrations in the aqueous feed were based on the concentrations found in the leach liquor of LCD panel glass at 0.1 g/mL S/L ratio. This study showed that extraction of indium could be increased at <293 K and stripping of indium could be increased at >293 K. Furthermore, by increasing D2EHPA concentration from 0.1 M to 0.25 M, extraction of indium could be increased from 70% to >95%. Jiaxu Yang, Christian Ekberg, and Teodora Retegan Copyright © 2014 Jiaxu Yang et al. All rights reserved. Synthesis of Titanium Containing SBA-15 and Its Application for Photocatalytic Degradation of Phenol Tue, 09 Sep 2014 08:41:42 +0000 We synthesized Ti-containing SBA-15 by one-pot hydrothermal method and extensively investigated its physicochemical properties and examined its photocatalytic activity to degrade phenol. It’s shown that appropriate amount of titanium could be effectively incorporated into the framework of SBA-15 without provoking structure change and the tetrahedrally coordinated titanium species were well-ordered in Ti-incorporated SBA-15. Under UV-irradiation, the Ti-containing SBA-15 exhibits good photocatalytic activity for phenol degradation in the simulated waste water. The higher photocatalytic activity of Ti-containing SBA-15 to degrade phenol was ascribed to the more titanium content and anatase titanium dioxide. In addition, the new photocatalyst displays a good regeneration and cyclic performance after six runs. Lili Yang, Zeyu Jiang, Sufeng Lai, Chongwen Jiang, and Hong Zhong Copyright © 2014 Lili Yang et al. All rights reserved. Experimental Study on Calcium Hydroxide-Assisted Delignification of Hydrothermally Treated Sweet Sorghum Bagasse Tue, 02 Sep 2014 07:19:16 +0000 The hydrothermally treated sweet sorghum bagasse (SSB) powder was treated using Ca(OH)2 to extract the lignin from it. Changes in chemical composition of SSB and the formation of sugars and hydrolytic products were studied. The optimum conditions of 10% (g/g substrate) Ca(OH)2 and 106.3 min of isothermal treatment residence time at 394 K resulted in 69.67 ± 1.26% of the lignin extracted from the hydrothermally treated SSB powder, producing a solid residue containing 68.29 ± 0.31% residual cellulose and 13.26 ± 0.32% residual lignin in it. The Ca(OH)2 concentration and isothermal treatment residence time were significant in the responses observed. Treatment using Ca(OH)2 is one of the potential processes for the on-farm processing of lignocellulosic materials. Jiby Kudakasseril Kurian, Yvan Gariepy, Mark Lefsrud, Valerie Orsat, Philippe Seguin, Varoujan Yaylayan, and G. S. Vijaya Raghavan Copyright © 2014 Jiby Kudakasseril Kurian et al. All rights reserved. Improved Transient Performance of a Fuzzy Modified Model Reference Adaptive Controller for an Interacting Coupled Tank System Using Real-Coded Genetic Algorithm Tue, 26 Aug 2014 00:00:00 +0000 The main objective of the paper is to design a model reference adaptive controller (MRAC) with improved transient performance. A modification to the standard direct MRAC called fuzzy modified MRAC (FMRAC) is used in the paper. The FMRAC uses a proportional control based Mamdani-type fuzzy logic controller (MFLC) to improve the transient performance of a direct MRAC. The paper proposes the application of real-coded genetic algorithm (RGA) to tune the membership function parameters of the proposed FMRAC offline so that the transient performance of the FMRAC is improved further. In this study, a GA based modified MRAC (GAMMRAC), an FMRAC, and a GA based FMRAC (GAFMRAC) are designed for a coupled tank setup in a hybrid tank process and their transient performances are compared. The results show that the proposed GAFMRAC gives a better transient performance than the GAMMRAC or the FMRAC. It is concluded that the proposed controller can be used to obtain very good transient performance for the control of nonlinear processes. Asan Mohideen Khansadurai, Valarmathi Krishnasamy, and Radhakrishnan Thota Karunakaran Copyright © 2014 Asan Mohideen Khansadurai et al. All rights reserved. Methyl Esters Selectivity of Transesterification Reaction with Homogenous Alkaline Catalyst to Produce Biodiesel in Batch, Plug Flow, and Continuous Stirred Tank Reactors Mon, 25 Aug 2014 08:48:14 +0000 Selectivity concept is essential in establishing the best operating conditions for attaining maximum production of the desired product. For complex reaction such as biodiesel fuel synthesis, kinetic studies of transesterification reaction have revealed the mechanism of the reaction and rate constants. The objectives of this research are to develop the kinetic parameters for determination of methyl esters and glycerol selectivity, evaluate the significance of the reverse reaction in transesterification reaction, and examine the influence of reaction characteristics (reaction temperature, methanol to oil molar ratio, and the amount of catalyst) on selectivity. For this study, published reaction rate constants of transesterification reaction were used to develop mathematical expressions for selectivities. In order to examine the base case and reversible transesterification, two calculation schemes (Case  1 and Case  2) were established. An enhanced selectivity was found in the base case of transesterification reaction. The selectivity was greatly improved at optimum reaction temperature (60°C), molar ratio (9 : 1), catalyst concentration (1.5 wt.%), and low free fatty acid feedstock. Further research might explore the application of selectivity for specifying reactor configurations. N. F. Nasir, W. R. W. Daud, S. K. Kamarudin, and Z. Yaakob Copyright © 2014 N. F. Nasir et al. All rights reserved. Thermochemical Equilibrium Model of Synthetic Natural Gas Production from Coal Gasification Using Aspen Plus Wed, 13 Aug 2014 07:03:09 +0000 The production of synthetic or substitute natural gas (SNG) from coal is a process of interest in Colombia where the reserves-to-production ratio (R/P) for natural gas is expected to be between 7 and 10 years, while the R/P for coal is forecasted to be around 90 years. In this work, the process to produce SNG by means of coal-entrained flow gasifiers is modeled under thermochemical equilibrium with the Gibbs free energy approach. The model was developed using a complete and comprehensive Aspen Plus model. Two typical technologies used in entrained flow gasifiers such as coal dry and coal slurry are modeled and simulated. Emphasis is put on interactions between the fuel feeding technology and selected energy output parameters of coal-SNG process, that is, energy efficiencies, power, and SNG quality. It was found that coal rank does not significantly affect energy indicators such as cold gas, process, and global efficiencies. However, feeding technology clearly has an effect on the process due to the gasifying agent. Simulations results are compared against available technical data with good accuracy. Thus, the proposed model is considered as a versatile and useful computational tool to study and optimize the coal to SNG process. Rolando Barrera, Carlos Salazar, and Juan F. Pérez Copyright © 2014 Rolando Barrera et al. All rights reserved. Effective Photodegradation of Methyl Orange Using Fluidized Bed Reactor Loaded with Cross-Linked Chitosan Embedded Nano-CdS Photocatalyst Tue, 05 Aug 2014 11:36:57 +0000 Chitosan-based photocatalyst composites containing CdS nanocrystals with and without glutaraldehyde or epichlorohydrin cross-linking treatments were investigated and the catalyzed photodegradation of methyl orange in aqueous solution was examined. In addition, the effects of catalyst dosage, initial dye concentration, and initial pH of the dye solution on the photodegradation kinetics were investigated. In this study, the effect of initial solution pH was more important than other factors. The photocatalyst composite could remove 99% dye in 80 minutes at pH 4. The catalyst composite was characterized by using X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), fourier transform infrared (FT-IR), and visible reflectance spectroscopy. The dye removal mechanism of methyl orange involved an initial sorption process followed by photodegradation. The sorption process underwent the pseudo-second order kinetics, while photodegradation followed the Langmuir-Hinshelwood kinetics. Although the glutaraldehyde cross-linked chitosan enhanced the initial dye sorption, the epichlorohydrin cross-linked catalyst composite demonstrated a better overall dye removal performance, especially in the photodegradation step. Both chitosan encapsulated catalyst with and without epichlorohydrin cross-linking demonstrated the same pseudo-first order photodegradation kinetic constant of 0.026 min−1 and the same dye removal capacity. The catalyst composite could be reused but the photocatalytic activity dropped successively in each cycle. Wai Szeto, Chi Wai Kan, C. W. M. Yuen, Shun-Wan Chan, and Kim Hung Lam Copyright © 2014 Wai Szeto et al. All rights reserved. Unsteady Flow of Reactive Viscous, Heat Generating/Absorbing Fluid with Soret and Variable Thermal Conductivity Wed, 23 Jul 2014 09:21:08 +0000 This study investigates the unsteady natural convection and mass transfer flow of viscous reactive, heat generating/absorbing fluid in a vertical channel formed by two infinite parallel porous plates having temperature dependent thermal conductivity. The motion of the fluid is induced due to natural convection caused by the reactive property as well as the heat generating/absorbing nature of the fluid. The solutions for unsteady state temperature, concentration, and velocity fields are obtained using semi-implicit finite difference schemes. Perturbation techniques are used to get steady state expressions of velocity, concentration, temperature, skin friction, Nusselt number, and Sherwood number. The effects of various flow parameters such as suction/injection (), heat source/sinks (S), Soret number (Sr), variable thermal conductivity , Frank-Kamenetskii parameter , Prandtl number (Pr), and nondimensional time on the dynamics are analyzed. The skin friction, heat transfer coefficients, and Sherwood number are graphically presented for a range of values of the said parameters. I. J. Uwanta and M. M. Hamza Copyright © 2014 I. J. Uwanta and M. M. Hamza. All rights reserved. Hydrogenation of Styrene Oxide to 2-Phenylethanol over Nanocrystalline Ni Prepared by Ethylene Glycol Reduction Method Thu, 17 Jul 2014 06:34:39 +0000 Nanocrystalline nickel prepared by glycol reduction method and characterized by XRD and magnetic measurements has been used as a catalyst for hydrogenation of styrene oxide to 2-phenylethanol. Effect of process variables such as particle size of the catalyst, temperature, and pressure have been optimized to achieve a maximum conversion of 98% of styrene oxide with 99% selectivity towards 2-phenylethanol. The structure of the transition state has been computed employing density functional theory and using Gaussian 09 suite. The enthalpy of reaction (ΔH) and activation energy () are calculated to be 85.3 kcal·mol−1 and 123.03 kcal·mol−1, respectively. A tentative mechanism for the reaction is proposed according to which atomized hydrogen and styrene oxide react together over the catalyst surface to produce 2-phenylethanol. Sunil K. Kanojiya, G. Shukla, S. Sharma, R. Dwivedi, P. Sharma, R. Prasad, M. Satalkar, and S. N. Kane Copyright © 2014 Sunil K. Kanojiya et al. All rights reserved. Performance Assessment of Sintered Metal Fiber Filters in Fluid Catalytic Cracking Unit Wed, 16 Jul 2014 00:00:00 +0000 A long-term test was performed in a fluid catalytic cracking (FCC) hot gas filtration facility using sintered metal candle filters. The operating temperature and pressure were maximum 55°C and 0.28 MPa, respectively. Specific particle sampling systems were used to measure the particle size and concentration directly at high temperature. The range of inlet particle concentration is from 150 to 165 mg/Nm3. The outlet particle concentration is in the range of 0.71–2.77 mg/Nm3 in stable operation. The filtration efficiency is from 98.23% to 99.55%. The inlet volume median diameter and the outlet volume median diameter of the particle are about 1 μm and 2.2 μm, respectively. The cake thickness is calculated based on the equation of Carman-Kozeny. The effects of operating parameters including face velocity, gas cleaning pressure, pulse duration, and maximum pressure drop were investigated. The optimal operating conditions and cleaning strategies were determined. The results show that sintered metal fiber filters are suitable for industrial application due to the good performance and high efficiency observed. Liang Yang, Zhongli Ji, Qiaoqi Xu, and Hao Li Copyright © 2014 Liang Yang et al. All rights reserved. Effect of Sulfation on Zirconia-Pillared Montmorillonite to the Catalytic Activity in Microwave-Assisted Citronellal Conversion Thu, 10 Jul 2014 11:59:12 +0000 Preparation of sulfated zirconia-pillared montmorillonite was carried out in two steps; zirconia pillarization and sulfation to zirconia-pillared montmorillonite. The prepared materials were characterized by using X-ray diffraction (XRD), measurement of the specific surface area, total pore volume and pore size distribution by the N2 adsorption method, scanning electron microscopy-energy dispersive X-ray (SEM-EDX), and surface acidity determination by using pyridine adsorption-FTIR analysis. The activity of the materials as catalysts was evaluated for a microwave-assisted conversion of citronellal. The results showed that the prepared materials had a physicochemical character that promoted high catalytic activity to convert citronellal. From varied Zr content and study of the effect of sulfation on the activity, it was found that Zr content and sulfation increase the surface acidity of the material as shown by the higher total conversion and tendency to produce menthol as a product of the tandem cyclization-hydrogenation mechanism. Is Fatimah, Dwiarso Rubiyanto, and Thorikul Huda Copyright © 2014 Is Fatimah et al. All rights reserved. Experimental Research and Numerical Simulation on Gas-Liquid Separation Performance at High Gas Void Fraction of Helically Coiled Tube Separator Wed, 09 Jul 2014 11:05:17 +0000 The industrial removal process of the light hydrocarbon and water from wet natural gas can be simulated in laboratory with the independently designed helically coiled tube gas-liquid separator. Experiment and numerical simulation are combined to analyze the influences of various inlet velocities and gas void fractions on the gas-liquid separation efficiency and pressure-drop between the inlet and outlet of the helically coiled tube. The results show that, at the inlet velocity of 4 m/s to 18 m/s and the gas void fraction of 88% to 97% for the gas-liquid mixture, the gas-liquid separation efficiency increases at the beginning and then decreases with increasing inlet velocity. Afterwards there is another increasing trend again. The gradient of pressure-drop increases slowly and then fast with the increasing inlet velocity. On the other hand, the gas-liquid separation efficiency first increases with the gas void fraction and then shows a decreasing trend while the pressure-drop keeps falling down with the gas void fraction increasing. Above all the optimal operating parameters of the helically coiled tube separator are inlet velocity of 13 m/s and gas void fraction of 93%, and the separation efficiency and pressure-drop are 95.2% and 0.3 MPa, respectively. Yongxue Zhang, Chan Guo, Hucan Hou, and Guomin Xue Copyright © 2014 Yongxue Zhang et al. All rights reserved. Growing Chlorella vulgaris in Photobioreactor by Continuous Process Using Concentrated Desalination: Effect of Dilution Rate on Biochemical Composition Wed, 02 Jul 2014 00:00:00 +0000 Desalination wastewater, which contains large amount of salt waste, might lead to severely environmental pollution. This study evaluated the effect of dilution rate ( day−1) on microalgal biomass productivity, lipid content, and fatty acid profile under steady-state condition of Chlorella vulgaris supplemented with concentrated desalination. Continuous culture was conducted for 55 days. Results show that the biomass productivity () varied from 57 to 126 mg L−1 d−1 (dry mass) when the dilution rate ranged from 0.1 to 0.3 day−1. At lowest dilution rate ( day−1), the continuous culture regime ensured the highest values of maximum biomass concentration ( mL−1) and protein content (52%). Biomass lipid content was an increasing function of . The most abundant fatty acids were the palmitic () at day−1 and the gamma-linolenic acid () at day−1 ones. These fatty acids present 14 to 18 carbons in the carbon chain, being mainly saturated and polyunsaturated, respectively. Overall, the results show that continuous culture is a powerful tool to investigate the cell growth kinetics and physiological behaviors of the algae growing on desalination wastewater. Ângelo Paggi Matos, Regina Coeli de Oliveira Torres, Luiz Rodrigo Ito Morioka, Elisa Helena Siegel Moecke, Kepler Borges França, and Ernani Sebastião Sant’Anna Copyright © 2014 Ângelo Paggi Matos et al. All rights reserved. Multimicronutrient Slow-Release Fertilizer of Zinc, Iron, Manganese, and Copper Tue, 01 Jul 2014 00:00:00 +0000 The process for the production of a slow-release micronutrient fertilizer is described. The compound contains zinc, iron, manganese, and copper as micronutrients and is produced by polymerizing a system containing phosphoric acid, zinc oxide, hematite, pyrolusite, copper sulfate, and magnesium oxide followed by neutralization of the polyphosphate chain with ammonium hydroxide. Changes in temperature, density, and viscosity of the reaction system during polymerization were studied. Reaction kinetics was studied at three different temperatures. Rate curves revealed a multistage process with essentially linear rates at each stage. Thus, each stage displayed zero order kinetics. The product was crystalline and revealed ordering of P-O-P chains. It had low solubility in water but high solubility in 0.33 M citric acid and 0.005 M DTPA. Three different field trials showed significant yield increments using the slow-release micronutrient fertilizer compared to the conventional micronutrients. Yield increments in rice were in the range of 10–55% over control (with no micronutrient) and up to 17% over the conventional micronutrient fertilizers. There were significant increases in total uptake of zinc, iron, and manganese in the grain. Slow-release fertilizers also produced significant yield increases in potato as well as significant increase in vitamin C content of the tuber. Siladitya Bandyopadhyay, Kunal Ghosh, and Chandrika Varadachari Copyright © 2014 Siladitya Bandyopadhyay et al. All rights reserved. Multiphase CFD Simulation of Solid Propellant Combustion in a Small Gun Chamber Wed, 25 Jun 2014 06:51:02 +0000 The interior ballistics simulations in 9 mm small gun chamber were conducted by implementing the process into the mixture multiphase model of Fluent V6.3 platform. The pressure of the combustion chamber, the velocity, and the travel of the projectile were investigated. The performance of the process, namely, the maximum pressure, the muzzle velocity, and the duration of the process was assessed. The calculation method is validated by the comparison of the numerical simulations results in the small gun with practical tests, and with lumped-parameter model results. In the current numerical study, both the characteristics and the performance of the interior ballistic process were reasonably predicted compared with the practical tests results. The impact of the weight charge on the interior ballistic performances was investigated. It has been found that the maximum pressure and the muzzle velocity increase with the increase of the charge weight. Ahmed Bougamra and Huilin Lu Copyright © 2014 Ahmed Bougamra and Huilin Lu. All rights reserved. Anaerobic Digestion and Biogas Production: Combine Effluent Treatment with Energy Generation in UASB Reactor as Biorefinery Annex Wed, 25 Jun 2014 00:00:00 +0000 The issue of residues and industrial effluents represents an unprecedented environmental challenge in terms of recovery, storage, and treatment. This work discusses the perspectives of treating effluents through anaerobic digestion as well as reporting the experience of using an upflow anaerobic sludge blanket (UASB) reactor as biorefinery annex in a pulp and paper industrial plant to be burned in the boilers. The performance of the reactors has shown to be stable under considerable variations in load and showed a significant potential in terms of biogas production. The reactors UASB treated 3600.00 m3 of effluent daily from a production of 150.00 tons. The biogas generation was 234.000 kg/year/mill, equivalent in combustible oil. The results of methane gas generated by the anaerobic system UASB (8846.00 kcal/m3) dislocate the equivalent of 650.0 kg of combustible oil (10000.00 kcal/kg) per day (or 234.000 kg/year). The production of 8846.00 Kcal/m3 of energy from biogas can make a run at industrial plant for 2 hours. This substitution can save US$ 128.700 annually (or US$ 550.0 of fuel oil/tons). The companies are invested in the use of the biogas in diesel stationary motors cycle that feed the boilers with water in case of storage electricity. Mauro Berni, Ivo Dorileo, Grazielle Nathia, Tânia Forster-Carneiro, Daniel Lachos, and Breno G. M. Santos Copyright © 2014 Mauro Berni et al. All rights reserved. Waste Material Adsorbents for Zinc Removal from Wastewater: A Comprehensive Review Tue, 24 Jun 2014 06:52:46 +0000 This review examines a variety of adsorbents and discusses mechanisms, modification methods, recovery and regeneration, and commercial applications. A summary of available researches has been composed by a wide range of potentially low-cost modified adsorbents including activated carbon, natural source adsorbents (clay, bentonite, zeolite, etc.), biosorbents (black gram husk, sugar-beet pectin gels, citrus peels, banana and orange peels, carrot residues, cassava waste, algae, algal, marine green macroalgae, etc.), and byproduct adsorbents (sawdust, lignin, rice husk, rice husk ash, coal fly ash, etc.). From the literature survey, different adsorbents were compared in terms of Zn2+ adsorption capacity; also Zn2+ adsorption capacity was compared with other metals adsorption. Thus, some of the highest adsorption capacities reported for Zn2+ are 168 mg/g powdered waste sludge, 128.8 mg/g dried marine green macroalgae, 73.2 mg/g lignin, 55.82 mg/g cassava waste, and 52.91 mg/g bentonite. Furthermore, modification of adsorbents can improve adsorption capacity. Regeneration cost is important, but if consumption of virgin adsorbent is reduced, then multiple economic, industrial, and environmental benefits can be gained. Finally, the main drawback of the already published Zn2+ adsorption researches is that their use is still in the laboratory stage mostly without scale-up, pilot studies, or commercialization. Haider M. Zwain, Mohammadtaghi Vakili, and Irvan Dahlan Copyright © 2014 Haider M. Zwain et al. All rights reserved. CFD Simulation for Separation of Carbon Dioxide-Methane Mixture by Pressure Swing Adsorption Thu, 19 Jun 2014 13:00:20 +0000 A developing technology for gas separations is pressure swing adsorption, which has been proven to be more economical and energy efficient compared to other separation methods like cryogenic distillation and membrane separation. A pressure swing adsorption (PSA) column, with carbon dioxide-methane as feed mixture and 6-FDA based polyimides as the adsorbent, was modeled and simulated in this work. Ansys Fluent 12.1, along with supplementary user defined functions, was used to develop a 2D transient Eulerian laminar viscous flow model for the PSA column. The model was validated by comparing the simulated results with established analytical models for PSA. The developed numerical model was used to determine the carbon dioxide concentration in the column as a function of time based on different operating conditions. Effect of various operating parameters like pressure, temperature, and flow rate on the separation efficiency has been studied and reported. Optimization studies were carried out to obtain suitable operating conditions for the feed gases separation. Simulation studies were carried out to determine the separation length required for complete separation of the feed mixture corresponding to different inlet feed concentrations which were entering the column at a given flow rate. K. Rambabu, L. Muruganandam, and S. Velu Copyright © 2014 K. Rambabu et al. All rights reserved. Comparative Study of Textural Characteristics on Methane Adsorption for Carbon Spheres Produced by CO2 Activation Tue, 17 Jun 2014 09:54:40 +0000 Resorcinol-formaldehyde resin polymer was used as raw material for preparation of carbon spheres. Samples were treated with CO2 flow at 850°C by varying activation times. The CO2 activation granted better pore development of pore structure. The experimental data of CH4 adsorption as a function of equilibrium pressure was fitted by Langmuir and Dubinin-Astakhov (D-A) models. It was concluded that the high surface area and micropore volume of carbon spheres did unequivocally determine methane capacities. In addition, a thermodynamic study of the heat of adsorption of CH4 on the carbon spheres was carried out. Adsorption of CH4 on carbon spheres showed a decrease in the adsorption heat with CH4 occupancy, and the heat of adsorption fell from 20.51 to 12.50 kJ/mol at 298 K and then increased to a little higher values at a very high loading (>0.70), indicating that CH4/CH4 interactions within the adsorption layer became significant. Wen Yang, Yanyan Feng, and Wei Chu Copyright © 2014 Wen Yang et al. All rights reserved. Experimental Investigation of Based Oxygen Carriers Used in Continuous Chemical-Looping Combustion Thu, 12 Jun 2014 00:00:00 +0000 Three materials of perovskite structure, (M = Mg or Mg and Ti), have been examined as oxygen carriers in continuous operation of chemical-looping combustion (CLC) in a circulating fluidized bed system with the designed fuel power 300 W. Natural gas was used as fuel. All three materials were capable of completely converting the fuel to carbon dioxide and water at 900°C. All materials also showed the ability to release gas phase oxygen when fluidized by inert gas at elevated temperature (700–950°C); that is, they were suitable for chemical looping with oxygen uncoupling (CLOU). Both fuel conversion and oxygen release improved with temperature. All three materials also showed good mechanical integrity, as the fraction of fines collected during experiments was small. These results indicate that the materials are promising oxygen carriers for chemical-looping combustion. Peter Hallberg, Malin Källén, Dazheng Jing, Frans Snijkers, Jasper van Noyen, Magnus Rydén, and Anders Lyngfelt Copyright © 2014 Peter Hallberg et al. All rights reserved. Optimization of Two-Step Acid-Catalyzed Hydrolysis of Oil Palm Empty Fruit Bunch for High Sugar Concentration in Hydrolysate Wed, 11 Jun 2014 13:18:32 +0000 Getting high sugar concentrations in lignocellulosic biomass hydrolysate with reasonable yields of sugars is commercially attractive but very challenging. Two-step acid-catalyzed hydrolysis of oil palm empty fruit bunch (EFB) was conducted to get high sugar concentrations in the hydrolysate. The biphasic kinetic model was used to guide the optimization of the first step dilute acid-catalyzed hydrolysis of EFB. A total sugar concentration of 83.0 g/L with a xylose concentration of 69.5 g/L and a xylose yield of 84.0% was experimentally achieved, which is in well agreement with the model predictions under optimal conditions (3% H2SO4 and 1.2% H3PO4, w/v, liquid to solid ratio 3 mL/g, 130°C, and 36 min). To further increase total sugar and xylose concentrations in hydrolysate, a second step hydrolysis was performed by adding fresh EFB to the hydrolysate at 130°C for 30 min, giving a total sugar concentration of 114.4 g/L with a xylose concentration of 93.5 g/L and a xylose yield of 56.5%. To the best of our knowledge, the total sugar and xylose concentrations are the highest among those ever reported for acid-catalyzed hydrolysis of lignocellulose. Dongxu Zhang, Yee Ling Ong, Zhi Li, and Jin Chuan Wu Copyright © 2014 Dongxu Zhang et al. All rights reserved. Bioethanol Production from Sugarcane Bagasse by a Novel Brazilian Pentose Fermenting Yeast Scheffersomyces shehatae UFMG-HM 52.2: Evaluation of Fermentation Medium Tue, 27 May 2014 10:16:53 +0000 Bioconversion of hemicellulosic sugars into second generation (2G) ethanol plays a pivotal role in the overall success of biorefineries. In this study, ethanol production performance of a novel xylose-fermenting yeast, Scheffersomyces shehatae UFMG-HM 52.2, was evaluated under batch fermentation conditions using sugarcane bagasse (SB) hemicellulosic hydrolysate as carbon source. Dilute acid hydrolysis of SB was performed to obtain sugarcane bagasse hemicellulosic hydrolysate (SBHH). It was concentrated, detoxified, and supplemented with nutrients in different formulations to prepare the fermentation medium to the yeast evaluation performance. S. shehatae UFMG-HM 52.2 (isolated from Brazilian Atlantic rain forest ecosystem) was used in fermentations carried out in Erlenmeyer flasks maintained in a rotator shaker at 30°C and 200 rpm for 72 h. The use of a fermentation medium composed of SBHH supplemented with 5 g/L ammonium sulfate, 3 g/L yeast extract, and 3 g/L malt extract resulted in 0.38 g/g of ethanol yield and 0.19 g L.h of volumetric productivity after 48 h of incubation time. F. A. F. Antunes, A. K. Chandel, T. S. S. Milessi, J. C. Santos, C. A. Rosa, and S. S. da Silva Copyright © 2014 F. A. F. Antunes et al. All rights reserved. Experimental Investigation of Biogas Reforming in Gliding Arc Plasma Reactors Mon, 26 May 2014 00:00:00 +0000 Biogas is an important renewable energy source. Its utilization is restricted to vicinity of farm areas, unless pipeline networks or compression facilities are established. Alternatively, biogas may be upgraded into synthetic gas via reforming reaction. In this work, plasma assisted reforming of biogas was investigated. A laboratory gliding arc plasma setup was developed. Effects of CH4/CO2 ratio (1, 2.33, 9), feed flow rate (16.67–83.33 cm3/s), power input (100–600 W), number of reactor, and air addition (0–60% v/v) on process performances in terms of yield, selectivity, conversion, and energy consumption were investigated. High power inputs and long reaction time from low flow rates, or use of two cascade reactors were found to promote dry reforming of biogas. High H2 and CO yields can be obtained at low energy consumption. Presence of air enabled partial oxidation reforming that produced higher CH4 conversion, compared to purely dry CO2 reforming process. P. Thanompongchart and N. Tippayawong Copyright © 2014 P. Thanompongchart and N. Tippayawong. All rights reserved. Separation Process of Nonpolar Gas Hydrate in Food Solution under High Pressure Apparatus Sun, 25 May 2014 11:01:08 +0000 Separation process of nonpolar gas hydrate formation in liquid food was experimentally studied under high pressure container. Xenon (Xe) gas was selected as hydrate forming gas and coffee solution was used as a sample of liquid food. The high-pressure stainless steel container having the inner diameter of 60 mm and the volume of 700 mL with a U-shaped stirrer was designed to carry out this experiment. A temperature of 9.0°C and Xe partial pressure of 0.9 MPa were set as a given condition. The experiment was designed to examine the effect of steel screen size, formation rate, temperature condition, and amount of Xe gas dissolving in the solution on the separation process which was indicated by concentration efficiency. Screen size of 200 and 280 mesh resulted in higher concentration efficiency than that of 100 mesh. The higher stirring rate caused the higher formation rate of Xe hydrate and created the smaller Xe hydrate crystals. At the condition giving the same solubility in water, temperature of 14.8°C resulted in lower concentration efficiency than 9.0°C. The increase in the amount of Xe gas dissolving in coffee solution caused the concentration efficiency to decrease; however, the concentration ratio between the final and initial concentration of the solution increased. Yohanes Aris Purwanto, Seiichi Oshita, Yasuhisa Seo, and Yoshinori Kawagoe Copyright © 2014 Yohanes Aris Purwanto et al. All rights reserved. A Numerical Study of Spray Characteristics in Medium Speed Engine Fueled by Different HFO/n-Butanol Blends Thu, 22 May 2014 09:10:40 +0000 In the present study, nonreacting and nonevaporating spray characteristics of heavy fuel oil (HFO)/n-butanol blends are numerically investigated under two different high pressure injections in medium speed engines. An Eulerian-Lagrangian multiphase scheme is used to simulate blend of C14H30 as HFO and 0%, 10%, 15%, and 20% by volume of n-butanol. OpenFOAM CFD toolbox is modified and implemented to study the effect of different blends of HFO/n-butanol on the spray characteristics at 600 and 1000 bar. To validate the presented simulations, current numerical results are compared against existing experimental data and good compliance is achieved. Based on the numerical findings, addition of n-butanol to HFO increases the particles volume in parcels at 600 bar. It was also found that blend fuels increase the number of spray particles and the average velocity of spray compared to pure HFO. Moreover, under injection pressure of 1000 bar, HFO/n-butanol blends compared to pure HFO fuel decrease particles volume in parcels of spray. Another influence of HFO/n-butanol blends is the decrease in average of particles diameter in parcels. Meanwhile, the effect of HFO/n-butanol on spray length is proved to be negligible. Finally, it can be concluded that higher injection pressure improves the spray efficiency. Hashem Nowruzi, Parviz Ghadimi, and Mehdi Yousefifard Copyright © 2014 Hashem Nowruzi et al. All rights reserved.