Current Issue : July - September Volume : 2015 Issue Number : 3 Articles : 7 Articles
Feedstock conversion and yield products are studied through a 3Dmodel simulating themain reactor of the fluid catalytic cracking\n(FCC) process. Computational fluid dynamic (CFD) is used with Eulerian-Eulerian approach to predict the fluid catalytic cracking\nbehavior. The model considers 12 lumps with catalyst deactivation by coke and poisoning by alkaline nitrides and polycyclic\naromatic adsorption to estimate the kinetic behavior which, starting from a given feedstock, produces several cracking products.\nDifferent feedstock compositions are considered. The model is compared with sampling data at industrial operation conditions.\nThe simulation model is able to represent accurately the products behavior for the different operating conditions considered. All\nthe conditions considered were solved using a solver ANSYS CFX 14.0.Thedifferent operation process variables and hydrodynamic\neffects of the industrial riser of a fluid catalytic cracking (FCC) are evaluated. Predictions fromthemodel are shown and comparison\nwith experimental conversion and yields products are presented; recommendations are drawn to establish the conditions to obtain\nhigher product yields in the industrial process....
The effect of solvent type and extraction method was investigated to study the antioxidant and antibacterial activity of Polygonum\nminus. Two extraction methods were used: a solvent extraction using Soxhlet apparatus and supercritical fluid extraction (SFE).\nThe antioxidant capacity was evaluated using the ferric reducing/antioxidant power (FRAP) assay and the free radical-scavenging\ncapacity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay.The highest polyphenol content was obtained from the medium polarity\nmethanol extract of the leaf portion (645.60 �± 166.68 gallic acid equivalents/100 g (GAEs/100 g)). It also showed the highest\nantioxidant power for FRAP and DPPH radical inhibition and exhibited the largest inhibition zone in antibacterial activity on\nBacillus subtilis (Gram+), Staphylococcus aureus (Gram+), and Escherichia coli (Gram?). The phase behavior and aldehyde profiles\nwere further investigated using SFE with different cosolvents. The results indicated that a 50% ethanol-water cosolvent yielded the\nbest aldehyde profiles in the presence of decanal, undecanal, and dodecanal....
The molecular gas chromatography and ion mass spectrometry parameters which obtained from analyses of gas chromatography and gas chromatography–mass spectrometry to proven normal alkanes and triterpanes parameters of the crude oil samples collected from Bahariya, Alam El Bueib and Khatatba reservoirs. The results revealing that the alkanes ratios of Bahariya and Alam El Bueib oils indicate a mature sample of mixed organic source, deposited under transitional environment. While the of Khatatba oil suggest that marine organic matters, mainly algae, deposited under reducing conditions. Triterpanes biomarkers showing that the Bahariya and Alam El Bueib oils that have the hydrocarbons derived from source rocks rich in carbonaceous organic matters. Khatatba oil is derived from marine organic matters with slightly input from terrigenous sources....
Cellulose extractions from wheat straw via hydrochloric, nitric, and sulfuric acid hydrolysis methods were carried out. X-ray\ndiffraction spectral analyses reveal that depending on the acid conditions used the structure of the cellulose exhibited a mixture\nof polymorphs (i.e., CI and CIII cellulose phases). In addition, the percent crystallinity, diameter, and length of the cellulose\nfibers varied tremendously as determined by X-ray diffraction and scanning electron microscopy. Thermal gravimetric analysis\nmeasurements revealed that the thermal stability of the extracted cellulose varied as a function of the acid strength and conditions\nused. Scanning electron microscopy analysis revealed that the aggregation of cellulose fibers during the drying process is strongly\ndependent upon the drying process and strength of the acids used....
A thermogravimetric analyzer was employed to investigate the thermal behavior and extract the kinetic parameters of Canadian\nlignite coal. The pyrolysis experiments were conducted in temperatures ranging from 298K to 1173K under inert atmosphere\nutilizing six different heating rates of 1, 6, 9, 12, 15, and 18Kmin?1, respectively. There are different techniques for analyzing\nthe kinetics of solid-state reactions that can generally be classified into two categories: model-fitting and model-free methods.\nHistorically, model-fitting methods are broadly used in solid-state kinetics and show an excellent fit to the experimental data but\nproduce uncertain kinetic parameters especially for nonisothermal conditions. In this work, different model-free techniques such\nas the Kissinger method and the isoconversional methods of Ozawa, Kissinger-Akahira-Sunose, and Friedman are employed and\ncompared in order to analyze nonisothermal kinetic data and investigate thermal behavior of a lignite coal. Experimental results\nshowed that the activation energy values obtained by the isoconversional methods were in good agreement, but Friedman method\nwas considered to be the best among the model-free methods to evaluate kinetic parameters for solid-state reactions.These results\ncan provide useful information to predict kinetic model of coal pyrolysis and optimization of the process conditions...
The most expensive component of a fuel cell is the membrane electrode assembly (MEA), which consists of an ionomer membrane\ncoated with catalyst material. Best-performing MEAs are currently fabricated by depositing and drying liquid catalyst ink on the\nmembrane; however, this process is limited to individual preparation by hand due to the membrane�s rapid water absorption that\nleads to shape deformation and coating defects.Acontinuous coating line can reduce the cost and time needed to fabricate the MEA,\nincentivizing the commercialization and widespread adoption of fuel cells. A pilot-scale membrane coating line was designed for\nsuch a task and is described in this paper. Accurate process control is necessary to prevent manufacturing defects from occurring\nin the coating line. A linear-quadratic-Gaussian (LQG) controller was developed based on a physics-based model of the coating\nprocess to optimally control the temperature and humidity of the drying zones. The process controller was implemented in the\npilot-scale coating line proving effective in preventing defects....
A new polyol synthesis method is described in which CuNi nanoparticles of different Cu/Ni atomic ratios were supported on both\ncarbon and gamma-alumina and compared with Pt catalysts using the reverse water gas shift, RWGS, reaction. All catalysts were\nhighly selective for CO formation. The concentration of CH4 was less than the detection limit. Cu was the most abundant metal\non the CuNi alloy surfaces, as determined by X-ray photoelectron spectroscopy, XPS, measurements. Only one CuNi alloy catalyst,\nCu50Ni50/C, appeared to be as thermally stable as the Pt/C catalysts. After three temperature cycles, from 400 to 700?C, the CO\nyield at 700?C obtained using the Cu50Ni50/C catalyst was comparable to that obtained using a Pt/C catalyst....
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