http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2013 , Hindawi Publishing Corporation . All rights reserved. Wed, 08 May 2013 14:34:19 +0000 http://www.hindawi.com/isrn/chemeng/2013/526375/ Chemical-looping with oxygen uncoupling (CLOU) is a novel combustion technology with inherent separation of carbon dioxide. The process is a three-step process which utilizes a circulating oxygen carrier to transfer oxygen from the combustion air to the fuel. The process utilizes two interconnected fluidized bed reactors, an air reactor and a fuel reactor. In the fuel reactor, the metal oxide decomposes with the release of gas phase oxygen (step 1), which reacts directly with the fuel through normal combustion (step 2). The reduced oxygen carrier is then transported to the air reactor where it reacts with the oxygen in the air (step 3). The outlet from the fuel reactor consists of only CO2 and H2O, and pure carbon dioxide can be obtained by simple condensation of the steam. This paper gives an overview of the research conducted around the CLOU process, including (i) a thermodynamic evaluation, (ii) a complete review of tested oxygen carriers, (iii) review of kinetic data of reduction and oxidation, and (iv) evaluation of design criteria. From the tests of various fuels in continuous chemical-looping units utilizing CLOU materials, it can be established that almost full conversion of the fuel can be obtained for gaseous, liquid, and solid fuels. Tobias Mattisson Copyright © 2013 Tobias Mattisson. All rights reserved. Thu, 14 Mar 2013 18:19:24 +0000 http://www.hindawi.com/isrn/chemeng/2013/261523/ Activated carbon cloths have received growing attention because they offer comparative advantages over the traditional powdered or granular forms of this well-known adsorbent, providing further potential uses for technological innovations in several fields. The present article provides an overview of research studies and advances concerned with the development of activated carbon cloths and their use as adsorbent in environmental applications, mostly reported in the last years. The influence of some fabrics and textile wastes used as precursors, and of main activation process variables on the development and physicochemical, mechanical and/or electrical properties of the resulting activated carbon cloths are first reviewed. Then, investigations dealing with the removal of water and air pollutants by adsorption onto activated carbon cloths, including advances toward optimizing their regeneration after organic vapors saturation, are presented. Ana Lea Cukierman Copyright © 2013 Ana Lea Cukierman. All rights reserved. Sun, 03 Mar 2013 15:34:17 +0000 http://www.hindawi.com/isrn/chemeng/2013/457805/ An analytical model for the temperature distribution of a spray column, three-phase direct contact heat exchanger is developed. So far there were only numerical models available for this process; however to understand the dynamic behaviour of these systems, characteristic models are required. In this work, using cell model configuration and irrotational potential flow approximation characteristic models has been developed for the relative velocity and the drag coefficient of the evaporation swarm of drops in an immiscible liquid, using a convective heat transfer coefficient of those drops included the drop interaction effect, which derived by authors already. Moreover, one-dimensional energy equation was formulated involving the direct contact heat transfer coefficient, the holdup ratio, the drop radius, the relative velocity, and the physical phases properties. In addition, time-dependent drops sizes were taken into account as a function of vaporization ratio inside the drops, while a constant holdup ratio along the column was assumed. Furthermore, the model correlated well against experimental data. Hameed B. Mahood, Adel O. Sharif, Seyed Ali Hosseini, and Rex B. Thorpe Copyright © 2013 Hameed B. Mahood et al. All rights reserved. Thu, 31 Jan 2013 11:49:54 +0000 http://www.hindawi.com/isrn/chemeng/2013/565471/ A thermodynamic investigation of gasification coupled chemical looping combustion (CLC) of carbon (coal) is presented in this paper. Both steam and CO2 are used for gasification within the temperature range of 500–1200°C. Chemical equilibrium model was considered for the gasifier and CLC fuel reactor. The trends in product compositions and energy requirements of the gasifier, fuel reactor, and air reactor were determined. Coal (carbon) gasification using 1.5 mol H2O and 1.5 mol CO2 per mole carbon at 1 bar pressure and 650°C delivered maximum energy (−390.157 kJ) from the process. Such detailed thermodynamic studies can be useful to design chemical looping combustion processes using different fuels. Sonali A. Borkhade, Preksha A. Shriwas, and Ganesh R. Kale Copyright © 2013 Sonali A. Borkhade et al. All rights reserved. Thu, 31 Jan 2013 10:39:53 +0000 http://www.hindawi.com/isrn/chemeng/2013/907425/ Zeolites have been shown to be useful catalysts in a large variety of reactions, from acid to base and redox catalysis. The particular properties of these materials (high surface area, uniform porosity, interconnected pore/channel system, accessible pore volume, high adsorption capacity, ion-exchange ability, and shape/size selectivity) provide crucial features as effective catalysts and catalysts supports. Currently, new applications are being developed from the considerable existing knowledge about these important and remarkable materials. Among them, those applications related to the development of processes with less impact on the environment (green processes) and with the production of alternative and cleaner energies are of paramount importance. Hydrogen is believed to be critical for the energy and environmental sustainability. It is a clean energy carrier which can be used for transportation and stationary power generation. In the production of hydrogen, the development of new catalysts is one of the most important and effective ways to address the problems related to the sustainable production of hydrogen. This paper explores the possibility to use zeolites as catalysts or supports of catalysts to produce hydrogen from renewable resources. Specifically, two approaches have been considered: reforming of biomass-derived compounds (reforming of bioethanol) and water splitting using solar energy. This paper examines the role of zeolites in the preparation of highly active and selective ethanol steam reforming catalysts and their main properties to be used as efficient water splitting photocatalysts. Antonio Chica Copyright © 2013 Antonio Chica. All rights reserved. Tue, 22 Jan 2013 09:20:45 +0000 http://www.hindawi.com/isrn/chemeng/2013/984163/ Reactive crystallization designed to separate nickel or copper ion from effluents has been advanced for applying to actual industrial wastewater containing impurities. In the primary reaction of this method, metal sulfate solution reacts with sodium carbonate solution in a semibatch crystallizer. In the present study, during the process of nickel or copper ions incorporation, inhibitory effect on seed growth of impurities, like cobalt, manganese, zinc, and borate and phosphate ions, was investigated. Through the 8-hour reactive crystallization, obtained particles’ characters and metals removal efficient were examined. Considering analyses data on metal component ratio in produced crystals, metal ions initial uptake rate was found to be different by the kind of seeds and impurities. And the centrifugation was performed against obtained crystals aimed for examining target metal purity improvement. The results indicated that copper components can incorporate and remove other metal ions easily. In addition, when the anions are used as impurities, depending on the kind of anions, the effect of damaging the surface of seeds or producing many fine particles has been confirmed. Y. Shimizu and I. Hirasawa Copyright © 2013 Y. Shimizu and I. Hirasawa. All rights reserved. Thu, 10 Jan 2013 15:13:40 +0000 http://www.hindawi.com/isrn/chemeng/2013/539209/ A new residence-time distribution (RTD) function has been developed and applied to quantitative dye studies as an alternative to the traditional advection-dispersion equation (AdDE). The new method is based on a jointly combined four-parameter gamma probability density function (PDF). The gamma residence-time distribution (RTD) function and its first and second moments are derived from the individual two-parameter gamma distributions of randomly distributed variables, tracer travel distance, and linear velocity, which are based on their relationship with time. The gamma RTD function was used on a steady-state, nonideal system modeled as a plug-flow reactor (PFR) in the laboratory to validate the effectiveness of the model. The normalized forms of the gamma RTD and the advection-dispersion equation RTD were compared with the normalized tracer RTD. The normalized gamma RTD had a lower mean-absolute deviation (MAD) (0.16) than the normalized form of the advection-dispersion equation (0.26) when compared to the normalized tracer RTD. The gamma RTD function is tied back to the actual physical site due to its randomly distributed variables. The results validate using the gamma RTD as a suitable alternative to the advection-dispersion equation for quantitative tracer studies of non-ideal flow systems. Irucka Embry, Victor Roland, Oluropo Agbaje, Valetta Watson, Marquan Martin, Roger Painter, Tom Byl, and Lonnie Sharpe Copyright © 2013 Irucka Embry et al. All rights reserved. Wed, 09 Jan 2013 14:20:25 +0000 http://www.hindawi.com/isrn/chemeng/2013/124767/ The food additive named polyglycerol polyricinoleate (PGPR) and identified with the code E-476 (PGPR) is used as emulsifier in tin-greasing emulsions for the baking trade and for the production of low-fat spreads. However, the main application of PGPR is in the chocolate industry, where, besides its action as an emulsifier, it also has important properties as a viscosity modifier and thus improves the moulding properties of the molten chocolate. An additional property of PGPR in chocolate is its ability to limit fat bloom. Known chemical methods for preparing this emulsifier involve long reaction times and high operating temperatures, which adversely affect the quality of the final product leading to problems of coloration and odors that could make it inadvisable for the food industry. As an alternative, the enzymatic synthesis of PGPR by the catalytic action of two lipases has been developed. The enzymes act in mild reaction conditions of temperature and pressure, neutral pH, and in a solvent-free system, which makes the process environmentally friendly and avoids side reaction, so that the product has a higher purity and quality. Josefa Bastida-Rodríguez Copyright © 2013 Josefa Bastida-Rodríguez. All rights reserved. Sun, 30 Dec 2012 15:05:08 +0000 http://www.hindawi.com/isrn/chemeng/2012/413657/ In this paper, a novel modeling technique has been attempted to develop the mathematical model for a bioreactor functioning at multiple operating regions. The first principle mathematical equations of the reactor are used with the POLYMATH software to generate essential data for the model development. A relative analysis is also carried out with the existing models in the literature. An optimal PID controller is then designed using a multiobjective particle swarm optimization algorithm. The controller tuning procedure is individually discussed for both the stable and unstable steady state regions. The controller tuned for each region is scheduled using a set-point scheduler to achieve a complete control over the bioreactor. The effectiveness of the proposed scheme has been confirmed through a comparative study with the controller tuning methods proposed in the literature. The results show that, the proposed method provides enhanced performance in effective reference tracking and load disturbance rejection with minimal ISE and IAE. Finally the proposed method is validated on the nonlinear bioreactor model in the presence of a measurement noise. The results testify that the PSO tuned PID performs well in tracking the change in biomass concentration at the entire operating region. V. Rajinikanth and K. Latha Copyright © 2012 V. Rajinikanth and K. Latha. All rights reserved. Sun, 30 Dec 2012 13:36:55 +0000 http://www.hindawi.com/isrn/chemeng/2012/290471/ Aqueous two phase systems (ATPSs) containing high molecular weight polyethylene glycol, PEG (10000), and completely biodegradable citrate salts (sodium citrate, potassium citrate, and ammonium citrate) with water were developed to recover the waste water proteins from a model tannery waste water system. The variations in the phase diagram were explained on the basis of ionic radius of cations, Gibbs free energy of hydration () of cations, and effective excluded volume (EEV) of salts. The salting-out capability of the cations followed the sequence: Sodium citrate > Potassium citrate > Ammonium citrate. Setschenow-type equations were used to correlate tie-line compositions. During partitioning studies, recovery of tannery waste water proteins in PEG 10000 + Sodium citrate ATPS was found superior to other systems. It was possible to recover 95.86% of proteins from tannery waste water in the bottom phase with PEG 10000 30% (w/w) + Sodium citrate 13% (w/w) at 30°C. The partition coefficients were correlated with the salt compositions by a quadratic equation and the coefficients were calculated. Selvaraj Raja and Vytla Ramachandra Murty Copyright © 2012 Selvaraj Raja and Vytla Ramachandra Murty. All rights reserved. Thu, 27 Dec 2012 17:30:59 +0000 http://www.hindawi.com/isrn/chemeng/2012/193862/ Tri-n-butyl phosphate (TBP) is a universal nuclear extractant, commercially used in the PUREX process for the last 60 years. However, it is prone to nitration and thermal degradation, and as a consequence a red-oil event may be initiated under several operating conditions resulting in severe pressurization of vessel/cell if venting is inadequate. In this work, an attempt was made to understand the reaction pathway of thermal decomposition of nitrated TBP in a flow reactor at atmospheric pressure. Many reaction products were identified and quantified by instrumental methods like HPLC-RI and GC-TCD. The experimental data was analysed with a power law model and the apparent rate constants were estimated. The activation energy for thermal decomposition of nitrated TBP, assuming an Arrhenius type of temperature dependency, was estimated to be  kJ·mol−1. The effect of both varying temperature and concentration of nitric acid on conversion of TBP into degradation products and products distribution was experimentally studied. Based on the experimental observations, a reaction mechanism framework for thermal decomposition of nitrated TBP is proposed. Lalit K. Patil, Vilas G. Gaikar, Shekhar Kumar, U. Kamachi Mudali, and R. Natarajan Copyright © 2012 Lalit K. Patil et al. All rights reserved. Wed, 26 Dec 2012 11:40:32 +0000 http://www.hindawi.com/isrn/chemeng/2012/373795/ Experiments simulating flooding scenario in various aqueous media for a long period were carried out to determine the adequacy of cement-clay composite for solidification/stabilization of spent organic radioactive liquid scintillator wastes. The final cement waste form blocks were immersed in three aqueous media, namely, seawater, groundwater, and tapwater. The immersion process lasted for increasing periods up to 540 days. Following each predetermined interval period, physical and mechanical evaluations of the immersed blocks were determined. In addition, the change in the hydration products was followed by X-ray diffraction and infrared spectroscopy as nondestructive analyses to recognize the deterioration in the microstructure that may occur due to the flooding event. Thermal analysis and scanning electron microscopy were performed to confirm the data obtained. H. El-Didamony, T. A. Bayoumi, and M. I. Sayed Copyright © 2012 H. El-Didamony et al. All rights reserved. Wed, 26 Dec 2012 07:39:04 +0000 http://www.hindawi.com/isrn/chemeng/2012/591587/ The performance of catalyst for glycerol reforming has been investigated in fixed-bed reactor using careful tailoring of the operational conditions. In this paper, a commercial Engelhard catalyst has been sized and compared to gas product distribution versus catalyst size, water-to-carbon ratio, and stability of the catalyst system. catalysts of three sizes (, , and  mm) are evaluated using glycerol: water mixture at to produce 2 L H2 g−1 cat h−1. The results indicate that  mm size pellet is showing minimum coking and maintaining same level of conversion even after several hours of reforming activity. Whereas studies on and  mm pellets indicate that carbon formation is affecting the reforming activity. Under accelerated aging studies, with 1 : 9 molar ratio of glycerol to water, 3 mg carbon g−1 cat h−1 was generated in 20 cycles, whereas 1 : 18 feed produced only 1.5 mg carbon g−1 cat h−1 during the same cycles of operation. The catalysts were characterized before and after evaluation by X-ray diffraction (XRD), BET surface area, scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDAX), CHNS analysis, transmission electron microscopy (TEM), and X-ray photo electron spectroscopy (XPS). G. Sadanandam, N. Sreelatha, M. V. Phanikrishna Sharma, S. Kishta Reddy, B. Srinivas, K. Venkateswarlu, T. Krishnudu, M. Subrahmanyam, and V. Durga Kumari Copyright © 2012 G. Sadanandam et al. All rights reserved. Tue, 25 Dec 2012 16:01:06 +0000 http://www.hindawi.com/isrn/chemeng/2012/836381/ The main purpose of this work is to give an overview on the chemical engineering aspects related with the production of probiotic cultures and bacteriocins. Firstly, some evidence of the potential of different Lactococci and Lactobacilli strains for prevention or treatment of different human diseases, or as growth promoters in farm animals is given. In addition, examples of different commercial dietary supplements containing probiotic lactoccocci and lactobacilli in combination or not with other probiotic bacteria are presented. Secondly, the main factors (cultivation method, culture media, and media composition) affecting the production of bacteriocins by lactoccocci and lactobacilli strains are showed. Examples of modelling procedures developed to describe the production of higher concentrations of biomass and bacteriocins in fed-batch cultures subjected or not to successive alkalizations are summarized. Finally, the corresponding mass balance equations performed in the latter cultures are presented to calculate the volumes of feeding substrates and the concentrations of nutrients (lactose, glucose, proteins, nitrogen, and phosphorous) added to the fermentation medium, as well as the concentrations of biomass and products in the fermentor just after each feeding. Nelson Pérez Guerra Copyright © 2012 Nelson Pérez Guerra. All rights reserved. Mon, 24 Dec 2012 08:43:34 +0000 http://www.hindawi.com/isrn/chemeng/2012/352574/ The present study attempts to investigate the effects of different chemical agents and chemical ratios on pore structure of coal-based activated carbons. The adsorption isotherm data of two series of activated carbons prepared from bituminous coal by chemical activation with potassium hydroxide and zinc chloride were used. Four well-known models of Dubinin-Stoeckli, Stoeckli, Horvath-Kawazoe, and improved Horvath-Kawazoe were applied for the characterization of these porous solids. Although the results showed some differences among the models that arise from their fundamental assumptions, in general they are found to be comparable. Results showed that samples activated by ZnCl2 provide higher-adsorption capacity than those from KOH. In each series, it was shown that the pore volume increases with increasing impregnation ratio, ranging from 50% to 200%. Activated carbons obtained at low chemical ratio in ZnCl2 series (up to 100%) showed microporous structure, while those with higher ratios became predominantly mesoporous. In the KOH series, increasing KOH created more micropores in the carbon structure in the whole range of studied chemical ratio. Ahmad Okhovat, Ali Ahmadpour, Farzaneh Ahmadpour, and Zahra Khaki Yadegar Copyright © 2012 Ahmad Okhovat et al. All rights reserved. Thu, 20 Dec 2012 14:21:22 +0000 http://www.hindawi.com/isrn/chemeng/2012/835391/ A central composite design (CCD) was used for the experimental design and results analysis to obtain the optimal processing parameters (acetic acid concentration, liquid to solid ratio, and stirring speed) for the extraction of pepsin soluble collagen (PSC) from muscles of cultured hybrid catfish of Clarias sp. (Clarias gariepinus × C. macrocephalus). Statistical analysis showed that the linear and quadratic terms of these three independent variables had significant effects on the yield of PSC. There was also an interaction between the ratio of liquid to solid and the stirring speed in affecting the extraction efficiency. Optimal conditions for a higher yield of PSC were an acetic acid concentration of 0.67 M, a liquid to solid ratio of 24.65 ml/g, and the stirring speed of 423.64 rpm. The verification of the optimization showed that the percentage error differences between the experimental and predicted values were in the range of 0.22–4.42%. The experimental values agreed with the predicted values, indicating an excellent fit of the model used and the success of the response surface methodology in modeling the extraction of PSC from the muscles of catfish. The experimental results were also fitted to the power law model and it was proven to be appropriate in describing the kinetics of collagen extraction process. Peck Loo Kiew and Mashitah Mat Don Copyright © 2012 Peck Loo Kiew and Mashitah Mat Don. All rights reserved. Tue, 18 Dec 2012 10:17:23 +0000 http://www.hindawi.com/isrn/chemeng/2012/610510/ Highly ordered and nanometer-scaled nickel wire arrays were successfully prepared by supercritical electrodeposition method using anodized aluminum oxide (AAO) template. The results show that the well-ordered and free-standing nickel nanowire arrays can be constructed uniformly on a titanium-coated silicon wafer after removing the AAO template. The diameter and length of the nickel nanowire in the arrays can be obtained, about 100 nm and 10 um, respectively. Based on Box-Behnken design and Response Surface Methodology (RSM), a regression model was built by fitting the experimental results with a polynomial equation. The current density, pressure, and temperature are critical important factors of the growth mechanism of deposited nanowires. The optimal length of nanowires, 10.03 μm, can be achieved at the following conditions: current density 0.23 A/cm2, pressure 107 bar, and temperature 53°C. Jau-Kai Wang, Jir-Ming Char, and Pei-Jung Lien Copyright © 2012 Jau-Kai Wang et al. All rights reserved. Sun, 16 Dec 2012 07:34:47 +0000 http://www.hindawi.com/isrn/chemeng/2012/753687/ In the past decade, the capture of anthropic carbonic dioxide and its storage or transformation have emerged as major tasks to achieve, in order to control the increasing atmospheric temperature of our planet. One possibility rests on the use of carbonic anhydrase enzymes, which have been long known to accelerate the hydration of neutral aqueous CO2 molecules to ionic bicarbonate species. In this paper, the principle underlying the use of these enzymes is summarized. Their main characteristics, including their structure and catalysis kinetics, are presented. A special section is next devoted to the main types of CO2 capture reactors under development, to possibly use these enzymes industrially. Finally, the possible application of carbonic anhydrases to directly store the captured CO2 as inert solid carbonates deserves a review presented in a final section. Alain C. Pierre Copyright © 2012 Alain C. Pierre. All rights reserved. Mon, 10 Dec 2012 14:52:19 +0000 http://www.hindawi.com/isrn/chemeng/2012/103715/ Corrosion of buried steel pipe is a permanent engineering problem and, albeit the counter measures against degradation, when the corrosion process takes place, the damage has costly impact. In order to study the corrosion behavior of pipelines, it is possible to use actual soil extracts or simulated soil solutions. The extract is much related to specific sites and consequently too strict to permit a general understanding. The simulated soil presents, as advantage, its inorganic characteristic and easy preparation. In this paper, we present some theoretical results concerning the chemical equilibria of NS1, NS2, NS3, and NS4 simulated soil solutions. Besides, we have studied the effect of the above four media in corrosion behavior and polarization curves were performed for an API 5L X65 steel. The theoretical findings show that each ionic concentration varies for a 6–12 pH range. The experimental data suggested that the corrosion currents decrease as high is the pH and increase as high is the chloride content. Notwithstanding these facts, for multielectrolyte solutions, a simple correlation with a given ion is not straightforward but the complementary approaches used here give useful insights. Rodrigo Antunes de Sena, Ivan Napoleão Bastos, and Gustavo Mendes Platt Copyright © 2012 Rodrigo Antunes de Sena et al. All rights reserved. Thu, 06 Dec 2012 15:28:53 +0000 http://www.hindawi.com/isrn/chemeng/2012/674209/ The effect of chemical activation on the adsorption of metals ions (Cr2+, Cu2+, Ni2+, Pb2+, Fe2+, and Zn2+) using waste Nigerian based bamboo, coconut shell, and palm kernel shell was investigated. The bamboo, coconut, and palm kernel shell were carbonized at 400°C–500°C and activated at 800°C using six activating agents. Chemical activation had significant effect on the iodine number and invariably increased the micropores and macropores of the activated carbons produced from bamboo, coconut, and palm kernel shell. It also affected the adsorption of metal ions and the type of carboneous material used for activation. The highest metal ions adsorbed were obtained from bamboo activated with HNO3. The cellulose nitrite formed during the activation of bamboo with HNO3 combined with high pore volume and low ash content of bamboo effectively create more reaction sites for adsorption of different metal ions. This shows that waste bamboo activated with HNO3 can effectively be used to remove metal ions from waste streams and in different metal recovery processes than activated carbon from coconut shell and palm kernel shell. F. T. Ademiluyi and E. O. David-West Copyright © 2012 F. T. Ademiluyi and E. O. David-West. All rights reserved. Wed, 05 Dec 2012 14:39:45 +0000 http://www.hindawi.com/isrn/chemeng/2012/327049/ A five-level-four-factor central composite design (CCD) with 54 assays was employed to study the effect of catalyst concentration (NaOH), reaction temperature, reaction time, and methanol/oil molar ratio on the methyl esters yield from Jatropha curcas oil (JCO) during its transesterification. Using response surface methodology (RSM), a quadratic polynomial equation was obtained for Jatropha curcas biodiesel (JCB) yield by regression analysis. Verification experiments confirmed the validity of the predicted model. The high free fatty acids (FFAs) (14.6%) of JCO could be reduced to 0.34% by acid-catalyzed esterification and a JCB yield of 98.3% was obtained with methanol/oil ratio (11 : 1) using NaOH as catalyst (1% w/w) in 110 min time at 55°C temperature. The predicted value of JCB yield is found to be in good agreement with the experimental value at the optimum level of input parameters. The properties of the biodiesel, thus, produced conform to the ASTM and IS specifications, making it an ideal alternative fuel for diesel engines. The model can be effectively used in oil industry to maximize the biodiesel yield from given oil. Prerna Goyal, M. P. Sharma, and Siddharth Jain Copyright © 2012 Prerna Goyal et al. All rights reserved. Tue, 04 Dec 2012 15:27:03 +0000 http://www.hindawi.com/isrn/chemeng/2012/842021/ Sliver nanocolloids have been synthesized by chemical reduction of sliver salt solution, characterized by SEM usage of nanoparticles. Sliver nanocolloids are treated with wool fibres and dyed wool fibres (direct and acid dyes). The physical properties, colour strength, and fastness properties have been studied for dyed wool fibres and ordinary wool fibres. It is observed that the fibres with nanotreated fibres have better strength than untreated wool fibres. It is also observed that there is considerable improvement in colour strength and colour fastness of silver nanocolloids-treated wool fibres (dyed). R. Perumalraj Copyright © 2012 R. Perumalraj. All rights reserved. Tue, 04 Dec 2012 12:23:08 +0000 http://www.hindawi.com/isrn/chemeng/2012/572421/ Application of artificial neural network (ANN) has been studied for simulation of the extraction process by supercritical CO2. Supercritical extraction of valerenic acid from Valeriana officianalis L. has been studied and simulated according to the significant operational parameters such as pressure, temperature, and dynamic extraction time. ANN, using multilayer perceptron (MLP) model, is employed to predict the amount of extracted VA versus the studied variables. Three tests, validation, and training data sets in three various scenarios are selected to predict the amount of extracted VA at dynamic time of extraction, working pressure, and temperature values. Levenberg-Marquardt algorithm has been employed to train the MLP network. The model in first scenario has three neurons in one hidden layer, and the models associated with the second and the third scenarios have four neurons in one hidden layer. The determination coefficients are calculated as 0.971, 0.940, and 0.964 for the first, second, and the third scenarios, respectively, demonstrating the effectiveness of the MLP model in simulating this process using any of the scenarios, and accurate prediction of extraction yield has been revealed in different working conditions of pressure, temperature, and dynamic time of extraction. Amir Rabiee Kenaree and Shohreh Fatemi Copyright © 2012 Amir Rabiee Kenaree and Shohreh Fatemi. All rights reserved. Mon, 03 Dec 2012 09:29:17 +0000 http://www.hindawi.com/isrn/chemeng/2012/982934/ Pressure swing adsorption (PSA) is a well-established gas separation technique in air separation, gas drying, and hydrogen purification separation. Recently, PSA technology has been applied in other areas like methane purification from natural and biogas and has a tremendous potential to expand its utilization. It is known that the adsorbent material employed in a PSA process is extremely important in defining its properties, but it has also been demonstrated that process engineering can improve the performance of PSA units significantly. This paper aims to provide an overview of the fundamentals of PSA process while focusing specifically on different innovative engineering approaches that contributed to continuous improvement of PSA performance. Carlos A. Grande Copyright © 2012 Carlos A. Grande. All rights reserved. Sun, 02 Dec 2012 11:39:00 +0000 http://www.hindawi.com/isrn/chemeng/2012/191308/ Hydrogen energy which has been recognized as an alternative instead of fossil fuel has been developed rapidly in fuel cell vehicles. Different hydrogen energy systems have different performances on environmental, economic, and energy aspects. A methodology for the quantitative evaluation and analysis of the hydrogen systems is meaningful for decision makers to select the best scenario. principal component analysis (PCA) has been used to evaluate the integrated performance of different hydrogen energy systems and select the best scenario, and hierarchical cluster analysis (CA) has been used to verify the correctness and accuracy of the principal components (PCs) determined by PCA in this paper. A case including 11 different hydrogen energy systems for fuel cell vehicles has been studied in this paper, and the system using steam reforming of natural gas for hydrogen production, pipeline for transportation of hydrogen, hydrogen gas tank for the storage of hydrogen at refueling stations, and gaseous hydrogen as power energy for fuel cell vehicles has been recognized as the best scenario. Also, the clustering results calculated by CA are consistent with those determined by PCA, denoting that the results calculated by PCA are scientific and accurate. Jing-Zheng Ren, Shi-yu Tan, and Li-chun Dong Copyright © 2012 Jing-Zheng Ren et al. All rights reserved. Thu, 29 Nov 2012 11:43:15 +0000 http://www.hindawi.com/isrn/chemeng/2012/941587/ Entropy generation analysis of a steady fluid flow with internal heat generation between two rotating cylinders was presented. The surface of the inner cylinder was kept at constant temperature while the surface of the outer cylinder was exposed to convection cooling. Analytical expressions for velocity and temperature distributions within the fluid were obtained. The effects of velocity ratio, Biot number, Brinkman number and other dimensionless parameters on the temperature distribution and local and total entropy generation rates were investigated and the results were presented graphically. M. El Haj Assad and Hakan F. Oztop Copyright © 2012 M. El Haj Assad and Hakan F. Oztop. All rights reserved. Thu, 29 Nov 2012 11:22:22 +0000 http://www.hindawi.com/isrn/chemeng/2012/860459/ Coating of simulated cement-based waste form was investigated by performing physical and chemical experimental tests. Moreover, X-ray diffraction, Fourier transform infrared spectroscopy, and electron microscope examination were applied on coated and noncoated simulated waste forms. Experimental results indicated that coating process improved the characterizations of cement-based waste form such as porosity and leachability. Diffusion coefficients and leach indecies of coated specimens were calculated and showed acceptable values. It could be stated that by coating cemented-waste form by bitumen emulsion, the radioactive contaminants were isolated, thus reducing the back release to surrounding environment during flooding by groundwater and consequently, saving the environment. H. M. Saleh Copyright © 2012 H. M. Saleh. All rights reserved. Thu, 29 Nov 2012 08:18:05 +0000 http://www.hindawi.com/isrn/chemeng/2012/329676/ The current work was devoted to study the solidification of bioproducts originated from the bioremediation of mixture of solid cellulose-based radioactive waste simulates using a mushroom (Pleurotus pulmonarius), in Portland cement. The obtained solidified waste form was subjected to mechanical integrity qualification after curing periods of 28 and 90 days. Chemical performance of the cement-waste form was also evaluated in different leachant media during 540 days. The results obtained gave useful information about the mechanical, physical, and chemical performances of the final cement-waste form incorporated the radioactive bioproducts. Moreover, it indicated that cement can provide a highly durable form that ensures a long-term stability of the solidified waste material and can act as a first barrier against the release of radiocontaminants from radioactive wastes to the surrounding environment. S. B. Eskander, S. M. Abd El-Aziz, H. El-Sayaad, and H. M. Saleh Copyright © 2012 S. B. Eskander et al. All rights reserved. Wed, 28 Nov 2012 13:54:18 +0000 http://www.hindawi.com/isrn/chemeng/2012/867198/ In the present paper, attempts have been made to control the production of pullulan by supplementing commercial source of carbons and protein, timely. Pullulan production was regulated by supplying full fat soya flour and hydrolyzed soya extract, individually and in combination. Pullulan quantification was assayed for sensitivity to pullulanase. Aureobasidium pullulans was found to produce 125.7 gL−1 of pullulan. The rotation speed of shake flask, the pH of broth, and the supply of air were maintained at 180 rpm, 5.9, and 1.5 vvm air, respectively. The effect of carbons and lipids on pullulan production was noticed to be substrate specific. However, after the lapse of 36 h, addition of full fat soya floor and hydrolyzed soya extract in combination enhanced the pullulan production 125.7 gL−1. Besides this, pH of broth was also noticed as a critical factor in monitoring pullulan biosynthesis. The newly isolated mutant Aureobasidium pullulans, having high potential for pullulan production as compared to existing data, can be well used for commercialization of pullulan. Sunil K. Sheoran, Kashyap Kumar Dubey, D. P. Tiwari, and Bhanu P. Singh Copyright © 2012 Sunil K. Sheoran et al. All rights reserved. Wed, 28 Nov 2012 08:56:37 +0000 http://www.hindawi.com/isrn/chemeng/2012/428974/ The effect of the concentration of sulfuric acid (SA) and temperature on structure and properties of cellulose (MCC) had been studied. Investigations showed that solubility of the initial sample at the room temperature increased gradually in the range of the acid concentration from 50 to 60 wt.% SA. When SA concentration reached 65 wt.%, then MCC sample dissolved completely. Cellulose regenerated from 65 wt.% SA had an amorphized structure and was characterized by high enzymatic digestibility. At increased temperature, 45°C, solubility of MCC in SA was raised, while yield and DP decreased. After treatment of MCC with hot 50–60 wt.% SA, the crystallinity degree of the obtained cellulose samples changed slightly, and these samples retained mainly the CI crystalline polymorph. However, when SA concentration reached 65 wt.%, then regenerated cellulose had CII crystalline polymorph, reduced crystallinity degree, and low DP. Using optimal conditions of the acidic treatment (57–60 wt.% SA, = 45°C;  h) in combination with the high-power disintegration permitted obtaining the CI nanocrystalline cellulose particles (NCP) having sizes 150–200 × 10–20 nm with the heightened yield (65–70%). These NCP can be used, for example, as reinforcing nanofillers for various composites. Michael Ioelovich Copyright © 2012 Michael Ioelovich. All rights reserved.