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Anaerobic Catalytic Oxidation Of Hydrocarbons In Moving Heat Waves. Case Simulation: Propane Oxidative Dehydrogenation In A Packed Adiabatic V-Ti Oxide Catalyst Bed, Andrey N. Zagoruiko

Andrey N Zagoruiko

The model simulation study has shown that the anaerobic process of oxidative dehydrogenation of propane under periodic alteration of feeding between propane and air may be realized in adiabatic catalyst beds in stable continuous cyclic mode in two-reactor scheme. In case of appropriate choice of process parameters (cycle duration, feeding flow rates) the process appears to be autothermal, i.e. it does not require any inlet gas preheating for stable operation. Compared to similar steady-state adiabatic process, the proposed process is characterized with much lower maximum catalyst temperatures, giving the way to process pure propane without diluting it with inert gases, …

Chalcopyrite: Bioleaching Versus Pressure Hydrometallurgy, Fathi Habashi

Fathi Habashi

While bioleaching of pyrite concentrates has been successfully used in industry to liberate gold from the sulfide matrix for subsequent cyanidation, the same technology cannot be recommended for leaching chalcopyrite concentrates for copper recovery. It will be shown to be uneconomical and cannot compete with pressure leaching technology.

Hybrid Artificial Neural Network-Genetic Algorithm Technique For Modeling And Optimization Of Plasma Reactor, Istadi, Nor Aishah Saidina Amin

Istadi

A hybrid artificial neural network-genetic algorithm (ANN-GA) numerical technique was successfully developed to model, to simulate, and to optimize a dielectric barrier discharge (DBD) plasma reactor without catalyst and heating. Effects of CH4/CO2 feed ratio, total feed flow rate, and discharge voltage on the performance of noncatalytic DBD plasma reactor were studied by an ANN-based simulation with a good fitting. From the multiobjectives optimization, the Pareto optimal solutions and corresponding optimal process parameter ranges resulted for the noncatalytic DBD plasma reactor owing to the optimization of three cases, i.e., CH4 conversion and C2+ selectivity, CH4 conversion and C2+ yield, and …

Synergistic Effect Of Catalyst Basicity And Reducibility On Performance Of Ternary Ceo2-Based Catalyst For Co2 Ocm To C2 Hydrocarbons, Istadi, Nor Aishah Saidina Amin

Istadi

The present investigation focuses on the synergistic effect of catalyst basicity and reducibility on the catalytic activity of binary and ternary CeO2-based catalysts in the CO2 oxidative coupling of methane (CO2 OCM). Proper amount of medium and strong basic sites together with lower amount of very strong basic sites are identified as pertinent factors in increasing the catalytic performance. The CO2-TPD and H2-TPR studies indicate synergistic effect between the catalyst basicity and reducibility for the 12.8CaO–6.4MnO/CeO2 ternary metal-oxide catalyst in enhancing the CO2 OCM performance.

Selective Conversion Of Methane To C2 Hydrocarbons Using Carbon Dioxide As An Oxidant Over Cao-Mno/Ceo2 Catalyst, Nor Aishah Saidina Amin, Istadi Istadi

Istadi

Carbon dioxide rather than oxygen seemed to be an alternative oxidant for the catalytic reaction of methane to produce C2 hydrocarbons via oxidative coupling of methane (CO2 OCM). The proper amount of medium and strong basic sites and the reducibility of the catalyst enhanced the C2 hydrocarbon selectivity and yield, which may be due to the synergistic effect of CeO2, CaO and MnO in the catalyst. The C2 hydrocarbons selectivity and yield of 75.6% and 3.9%, respectively were achieved over the 12.8CaO-6.4MnO/CeO2 catalyst. The catalyst showed a remarkable stability for 20 h time on stream in the CO2 OCM process

Co-Generation Of Synthesis Gas And C2c Hydrocarbons From Methane And Carbon Dioxide In A Hybrid Catalytic-Plasma Reactor: A Review, Istadi, Nor Aishah Saidina Amin

Istadi

The topics on conversion and utilization of methane and carbon dioxide are important issues in tackling the global warming effects from the two greenhouse gases. Several technologies including catalytic and plasma have been proposed to improve the process involving conversion and utilization of methane and carbon dioxide. In this paper, an overview of the basic principles, and the effects of CH4/CO2 feed ratio, total feed flow rate, discharge power, catalyst, applied voltage, wall temperature, and system pressure in dielectric-barrier discharge (DBD) plasma reactor are addressed. The discharge power, discharge gap, applied voltage and CH4/CO2 ratio in the feed showed the …

Oxidative Carbonylation And Conjugated Processes With Carbon Monoxide Participation Catalyzed By Palladium Complexes (In Russian), Lev G. Bruk, Irina V. Oshanina, Sergey N. Gorodsky, Oleg N. Temkin

Sergey N. Gorodsky

No abstract provided.

Two-Fluid Eulerian Simulation Of Bubble Column Reactors With Distributors, Abid Akhtar

Abid Akhtar Mr

A two-fluid Eulerian model has been used to study the effect of various sieve plate gas distributors and gas superficial velocities on the hydrodynamics of three-dimensional flow in bubble columns. Turbulence has been modelled using the k-ƒÕ turbulence model. Inclusion of gas distributors showed asymmetric flow patterns which are otherwise smoothened when modelled using a uniform gas source. The asymmetric behaviour increased with increase in the number of holes giving better mixing. The gas hold-up increased with superficial gas velocity, and was independent of the distributor design at high superficial gas velocities. Comparison of simulation results with the experimental work …

Selective Catalytic Oxidation Of Hydrogen Sulfide For Cleanup Of Claus Tail Gases: Startup Of Industrial Installation At Omsk Refinery, Andrey N. Zagoruiko, Vladimir V. Mokrinskii, Nataly A. Chumakova, Galina A. Bukhtiarova, Sergey V. Vanag, Tatiana V. Borisova, Galina G. Isaeva, Boris G. Kozorog

Andrey N Zagoruiko

The presentation describes the experience of development and commercialization of the catalyst and the process for selective oxidation of H2S into sulfur, which was put into industrial operation at Omsk Refinery (Omsk, Russia) in 2004.

New Oscillating Reaction – Phenylacetylene Oxidative Carbonylation To Anhydride Of Phenylmaleic Acid (In Russian), Sergey N. Gorodsky, Olga V. Kasatkina, Lev G. Bruk, Oleg N. Temkin

Sergey N. Gorodsky

No abstract provided.

The Effects Of Some Methacrylate Monomers Used As Liquid Component On Tensile And Flexural Strengths Of A Poly (Methyl Methacrylate) Denture Base Resin., Selda Keskin

No abstract provided.

Investigation Of Coke Deposition And Coke Inhibition By Organosulfur Compounds In The Pyrolysis Of Naphtha In The Jet Stirred Reactor System, D Salari, A Niaei, J Towfighi, P Panahi, Reza Nabavi

Seyed Reza nabavi

No abstract provided.

An Algebraic Formulation For An Equal Area Rule To Determine Phase Compositions In Simple Reactive Systems, Gustavo A. Iglesias-Silva, Adrian Bonilla-Petriciolet, Kenneth R. Hall

Adrian Bonilla-Petriciolet

Equal area rules are fundamental constructs in thermodynamics for determining conditions of equilibrium. The Maxwell equal area rule (MEAR) provides saturated volumes when the two-phase isotherm/isobar cuts the van derWaals loops such that the areas above and below are equal. Another equal area rule exists for determining the phase compositions in a binary mixture when plotting the derivative of the total Gibbs energy against the composition. In this work, we show that in the determination of phase compositions in reactive systems, an equal area rule exists under the correct transformation of the mole fractions.

Cálculo De Puntos Críticos Empleando Una Estrategia De Optimización Global Estocástica, Francisco Sánchez-Mares, Adrian Bonilla-Petriciolet

Adrian Bonilla-Petriciolet

The determination of critical points in multicomponent mixtures is important for both theoretical and experimental issues in the context of Chemical Engineering and related areas. In this work, we introduce a new method to perform critical point calculations which is based on the Heidemann and Khalil’s formulation and the stochastic global optimization method Simulated Annealing. Numerical performance (reliability and efficiency) of this strategy has been tested in the prediction of critical conditions of several multicomponent mixtures. Our results show that proposed method is generally robust for these calculations. However, the computational time is still significant for multicomponent systems.

Performance Of Stochastic Optimization Methods In The Calculation Of Phase Stability Analyses For Nonreactive And Reactive Mixtures, Adrian Bonilla-Petriciolet, Richard Vázquez-Román, Gustavo A. Iglesias-Silva, Kenneth R. Hall

Adrian Bonilla-Petriciolet

In this paper, we perform a comparative study of four stochastic optimization methods for calculating the phase stability of reactive and nonreactive mixtures. We have compared the algorithms: simulated annealing, very fast simulated annealing, a modified version of direct search simulated annealing, and stochastic differential equations. We test the numerical performance and reliability of these methods using several stability problems. From our results, the simulated annealing algorithm appears to be the most reliable method for minimization of the tangent plane distance function for both reactive and nonreactive mixtures.

Bubble And Dew Point Calculations In Multicomponent And Multireactive Mixtures, Adrian Bonilla-Petriciolet, Azucena Acosta-Martínez, Ulises I. Bravo-Sánchez, Juan Gabriel Segovia-Hernández

Adrian Bonilla-Petriciolet

Bubble and dew point calculations are useful in chemical engineering and play an important role in the study of separation equipments for non-reactive and reactive mixtures. To the best of the authors’s knowledge, few methods have been proposed for these calculations in systems with several chemical reactions. The objective of this paper is to introduce new conditions for performing bubble and dew point calculations in reactive mixtures. We have developed these conditions based on the application of transformed variables of Ung and Doherty (1995). Using these transformed variables, the solution space is restricted to compositions that are already at chemical …

Dynamic Analysis Of Distillation Sequences With Thermal Coupling (With Unidirectional Flows) For The Separation Of Ternary Mixtures, Juan Gabriel Segovia-Hernández, Adrian Bonilla-Petriciolet, Luis I. Salcedo-Estrada

Adrian Bonilla-Petriciolet

The Petlyuk distillation system has been considered with special interest because of the high energy savings it can provide with respect to the operation of sequences based on conventional columns. The original design of the Petlyuk structure, however, shows two interconnections that seem to affect its operational and controllability properties. To overcome this problem, two alternate structures have been suggested that use unidirectional flows of the vapor or liquid interconnecting streams. In this work, a comparative analysis of the control properties of the Petlyuk column and the alternate arrangements with unidirectional interconnecting flows is presented. Through a singular value decomposition …

Textural And Fractal Properties Of Cuo/Al2o3 Catalyst Supports, Zeljko D. Cupic

Zeljko D Cupic

No abstract provided.

Forest Fires In Portugal: How They Happen And Why They Happen, João F. Gomes

João F Gomes

Forest fires are recurrent phenomena in Southern European countries, due to the nature of Mediterranean forest and climatic characteristics. However, in Portugal, in the last years, forest fires attained the dimension of public calamity and are now endangering sustainability of forest itself, as well as several derived economic activities. This paper reviews the past and current situation of forest fires in Portugal, analyses its main causes and consequences and derives recommendations to effectively overcome this problem.

Leaching Of Heavy Metals From Steelmaking Slags, João F. Gomes

João F Gomes

Leaching tests with EAF and Ladle slags were performed, using a flow through test and the standard batch test DIN 38414-S4. The previous method was used to simulate the leaching behaviour of steel slags under landfill. The chemical analysis of the leachates during this period shows, in general, for both types of slag, an increase of heavy metal releases with ageing. Standard test method DIN 38414-S4 was used to evaluate leachability of heavy metals by water in unprocessed slags. After more than one year of trials, slag samples submitted to these trials presented very low total leaching levels. The most …

Estimation Of Uncertainty In The Determination Of Nitrogen Oxides Emissions, João F. Gomes

João F Gomes

This paper presents a methodology for estimation of uncertainty on a reference test method for determination of nitrogen oxides concentration in gaseous emissions from stationary sources. As a first stage for identification of uncertainty sources, the test method is carefully reviewed in detail. Afterwards, these sources are quantified, bearing in mind its partial uncertainty, allowing the determination of the combined uncertainty and, finally, the expanded uncertainty. The calculation procedure was implemented into an excel calculation file. Using this file and considering several numerical applications from real situations, uncertainities around 15 mg/Nm3 over determined concentrations of 350 mg/Nm3 of NOx (expressed …

Fume Emissions During Metal Arc Welding, João F. Gomes

João F Gomes

No abstract provided.

Sulphated Almcm-41: Mesoporous Solid Brønsted Acid Catalyst For Dibenzoylation Of Biphenyl, Eng-Poh Ng, Hadi Nur, Mohd Nazlan Mohd Muhid, Halimaton Hamdan

Eng-Poh Ng

Sulphated mesoporous solid Brønsted acid catalyst (SO4-AlMCM-41) was prepared by impregnation of sulphuric acid on the surface of H-AlMCM-41. Characterization of SO4-AlMCM-41 by pyridine adsorption studies and 27Al MAS NMR showed that the presence of Brønsted acidity was correlated with octahedrally coordinated aluminium and solvent environment. Catalytic study demonstrated that the SO4-AlMCM-41 catalyst has a higher activity in the dibenzoylation of biphenyl with benzoyl chloride than sulphuric acid, H-AlMCM-41 and sulphated amorphous silica.