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Development of kinetic model for CO hydrogenation reaction over supported Fe-Co-Mn catalyst
, Article New Journal of Chemistry ; Volume 41, Issue 18 , 2017 , Pages 10452-10466 ; 11440546 (ISSN) ; Abdouss, M ; Mirzaei, N ; Zamani, Y ; Sharif University of Technology
Royal Society of Chemistry
2017
Abstract
Kinetic modeling of CO hydrogenation over Fe-Co-Mn catalyst was investigated; a ternary catalyst was prepared using incipient wetness impregnation. The kinetic parameters were determined from experiments carried out in a fixed bed micro-reactor under the following process conditions: T = 523.15-533.15 K, P = 1-10 bar, H2/CO = 1/1-3/1 and space velocity = 4500 h-1. Seventeen rate expressions were derived from five different mechanisms according to Langmuir-Hinshelwood-Hougen-Watson (LHHW) and Eley-Rideal (ER) mechanisms and were tested against the experimental data. Non-linear regression method was used to estimate different kinetic parameters; according to the obtained experimental results...
Beneficial Role of oxygen in co and propylene oxidation over a pt-pd-based wiremesh catalyst as a retrofit emission control device for four-stroke gasoline spark-ignited motorcycles
, Article Energy and Fuels ; Volume 35, Issue 12 , 2021 , Pages 10122-10133 ; 08870624 (ISSN) ; Hamzehlouyan, T ; Hosseini, V ; Mayer, A ; Sharif University of Technology
American Chemical Society
2021
Abstract
Over 200 million motorcycles in use worldwide account for a substantial portion of global mobile source total hydrocarbons (THC) and carbon monoxide (CO) emissions. In Tehran, capital of Iran, ultrarich inefficient combustion in gasoline-fueled motorcycles results in significantly high CO and THC emissions. Motorcycle catalysts can reduce CO and C3H6(as a representative hydrocarbon) emission factors by 60-80%. In the present work, CO and propylene oxidation over a commercial Pt-Pd-based wiremesh catalyst is studied in a flow reactor setup under simulated conditions relevant to 125 cc four-stroke gasoline carburetor motorcycles. Steady-state individual and co-oxidation tests for CO and...
Numerical study on the effects of creating rotationary flow inside the injector nozzle and changing fuel injection angle on the performance and emission of caterpillar diesel engine
, Article Journal of the Brazilian Society of Mechanical Sciences and Engineering ; Volume 44, Issue 1 , 2022 ; 16785878 (ISSN) ; Firuzi, R ; Rostami, M ; Mardani, A ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
One way of improving the performance of diesel engines is to produce modifications in the fuel supply systems. In this article, the effects of creating rotationary flow inside the nozzle and changing fuel injection angle on the performance and emission of caterpillar diesel engine have been examined in two separate stages using AVL FIRE software. First, the injector and its spray have been simulated with various geometries. The numerical results of this step indicate that creating rotationary flow inside the nozzle decreases the penetration length, while increases fuel spray cone angle and improves atomization quality. In the subsequent step, the diesel engine has been simulated with its...
Adsorption of carbon monoxide on SixGe4-x(x = 0-4) nano-clusters: A hybrid meta density functional study
, Article Molecular Physics ; Volume 108, Issue 10 , 2010 , Pages 1317-1327 ; 00268976 (ISSN) ; Gobal, F ; Sharif University of Technology
2010
Abstract
Theoretical study of carbon monoxide adsorption on SixGe4 - x(x = 0-4) nano-clusters has been carried out using advanced hybrid meta density functional method of Truhlar (MPW1B95). MG3 semi-diffuse (MG3S) and correlation consistent valence basis sets with relativistic core potential were employed to improve the results. The agreement of the calculated ionization and dissociation energies with experimental values validates the reported structures of nano-clusters and justifies the use of hybrid meta density functional method. The geometry, adsorption energy, charge distribution, and vibrational frequency of CO adsorption on all possible structures were investigated. The maximum vibrational...
Study of Tehran Air Pollutants Dispersion with CMAQ Modeling System
, M.Sc. Thesis Sharif University of Technology ; Arhami, Mohammad (Supervisor)
Abstract
Tehran air quality is facing a real crisis. Reports of pertinent organizations show air quality is deteriorating in recent years and unhealthy days are increasing. As a result, study and planning in order to change this trend and moving toward improving air quality is a necessity. On the other hand, in order to make proper decisions and choosing effective approaches considering cost-effective attribute and legal, temporal and budget restrictions, selecting the right tool is essential. Air quality models are the tools which in a cost saving manner and reasonable time can provide the required results for researchers, decision makers and legislators. An applicable model correspondent with urban...
Numerical study of CO and CO2 formation in CH4/H2 blended flame under MILD condition
, Article Combustion and Flame ; Volume 160, Issue 9 , September , 2013 , Pages 1636-1649 ; 00102180 (ISSN) ; Tabejamaat, S ; Hassanpour, S ; Sharif University of Technology
2013
Abstract
Reduction of air pollutants formation from hydrocarbon combustion process requires improvements in combustion systems. The moderate and intense low oxygen dilution (MILD) combustion technique is an opportunity to achieve such a goal. MILD combustion is a combustion regime which can be attained by high temperature preheating and high level dilution. In this paper, the mechanism of CO and CO2 formation for a CH4/H2 fuel mixture is studied under MILD combustion condition of a jet in hot coflow (JHC) burner. This investigation is done using the computational fluid dynamics (CFD) and also zero dimensional well-stirred reactor (WSR) analysis. The RANS equations with modified k-ε equations are...
Exergy, economic, and environmental analysis of a PEM fuel cell power system to meet electrical and thermal energy needs of residential buildings
, Article Journal of Fuel Cell Science and Technology ; Volume 9, Issue 5 , 2012 ; 1550624X (ISSN) ; Ehyaei, M. A ; Mozafari, A ; Atabi, F ; Hajidavalloo, E ; Shalbaf, S ; Sharif University of Technology
ASME
2012
Abstract
In this paper, a Polymer Electrolyte Membrane (PEM) fuel cell power system including burner, steam reformer, heat exchanger, and water heater has been considered. A PEM fuel cell system is designed to meet the electrical, domestic hot water, heating, and cooling loads of a residential building located in Tehran. Operating conditions of the system with consideration of the electricity cost has been studied. The cost includes social cost of the environmental pollutants (e.g. CO 2, CO and NO). The results show that the maximum energy needs of the building can be met by 12 fuel cell stacks with nominal capacity of 8.5 kW. Annual average electricity cost of thissystem is equal to 0.39 US$/kWh and...
Supercritical gasification of biomass: Thermodynamics analysis with Gibbs free energy minimization
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Volume 34, Issue 2 , Dec , 2011 , Pages 163-176 ; 15567036 (ISSN) ; Pazuki, G. R ; Vossoughi, M ; Saboohi, Y ; Hashemi, N ; Sharif University of Technology
2011
Abstract
Gasification of biomass in supercritical water is a successful technology for hydrogen production especially by using wet biomass. The whole process, from feeding to purification of hydrogen, consists of a lot of equipment, such as pumps, heat exchangers, heaters, reactors, etc. Because the main reactions take place in the gasification reactor, the gasifier is the most important equipment of the process. In this article, a thermodynamic model, including chemical equilibrium in the reactor that is based on Gibbs free energy minimization, is developed to estimate equilibrium composition for gasification of biomass in supercritical water for hydrogen production. For this analysis, we use three...
Numerical study on the effects of fuel injector on carbonaceous pollutants in a kerosene combustor
, Article 13th International Energy Conversion Engineering Conference, 27 July 2015 through 29 July 2015 ; July , 2015 ; 9781624103766 (ISBN) ; Ghafourizadeh, M ; Schneider, G. E ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc, AIAA
2015
Abstract
A gaseous-kerosene/air turbulent nonpremixed flame in a combustion chamber is simulated to investigate the effects of fuel-injector cone-angle on the pollutions of soot nano-particles, carbon monoxide, and carbon dioxide. We use a two-equation soot model in our studying, consider a detailed chemical scheme consisting of 121 species and 2613 elementary reactions, use the flamelet model, employ the presumed-shape probability density functions PDFs, apply the two-equation κ-ε turbulence model with round-jet corrections, and take into account the radiation effects assuming optically-thin flame in our numerical modeling. This research concentrates on investigating the impacts of kerosene injector...
The effects of baffle plate on soot nano-aerosol and pollutant productions in a JP-fueled combustor
, Article 54th AIAA Aerospace Sciences Meeting, 2016, 4 January 2016 through 8 January 2016 ; 2016 ; 9781624103933 (ISBN) ; Ghafourizadeh, M ; Schneider, G. E ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc, AIAA
2016
Abstract
In this paper, the effects of a baffle plate on flame deflection and its throttling are investigated numerically in a combustor consuming jet propellant JP. We study the plate effects on the resulting soot volume fraction, soot particles diameter, mass fractions of carbon monoxide (CO), carbon dioxide (CO2), and benzene (C6H6). We use a two-equation turbulence model, a PAH-inception two-equation soot model imposing oxidation due to OH agents, a detailed chemical kinetic consisting of 121 species and 2613 elementary reactions, and the flamelet combustion model to perform the current study. We also take into account the turbulence-chemistry interaction using the presumed-shape probability...
Effect of reformer gas blending on homogeneous charge compression ignition combustion of primary reference fuels using multi zone model and semi detailed chemical-kinetic mechanism
, Article Applied Energy ; Volume 179 , 2016 , Pages 463-478 ; 03062619 (ISSN) ; KhoshbakhtiSaraya Saray, R ; Hosseini, V ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
This study mainly aims to investigate the effect of reformer gas (RG) addition on the performance of homogeneous charge compression ignition (HCCI) engines using a multi zone model. The developed model is validated using a wide range of experimental data of a cooperative fuel research engine. Blended fuels of isooctane and n-heptane, known as primary reference fuels, with different octane numbers are used as the main engine fuel. A semi detailed chemical-kinetic mechanism containing 101 species and 594 reactions is used to simulate the combustion of blended fuels. The study is performed with different percentages of RG (0–30%). The results show that RG reduces the rate of some H abstraction...
Process integration of membrane reactor for steam methane reforming for hydrogen separation with CO2 capture in power production by natural gas combined cycle
, Article 9th International Conference on Greenhouse Gas Control Technologies, GHGT-9, Washington DC, 16 November 2008 through 20 November 2008 ; Volume 1, Issue 1 , 2009 , Pages 279-286 ; 18766102 (ISSN) ; Soltanieh, M ; US Department of Energy ; Sharif University of Technology
2009
Abstract
In this paper simulation results for integration of CO2 pre-combustion capture by steam methane reforming (SMR) in membrane reactors (MR) with natural gas fired combined cycle (NGCC) power plants are presented. The integrated combined cycle was simulated by GTPRO (Thermoflow) simulator along with the results from simulation of membrane reactor for SMR process developed in this work. The results show that the overall efficiency of the integrated combined cycles decreased due to the energy required for SMR process. On the other hand, by integration of MR in combined cycles, emissions of CO2 to the atmosphere can be avoided. © 2009 Elsevier Ltd. All rights reserved
Modified LaCoO3 nano-perovskite catalysts for the environmental application of automotive CO oxidation
, Article Chemical Engineering Journal ; Volume 148, Issue 2-3 , 2009 , Pages 306-311 ; 13858947 (ISSN) ; Baghalha, M ; Kazemian, H ; Sharif University of Technology
2009
Abstract
Modified perovskite-type oxides were synthesized through co-precipitation and conventional citrate methods. The synthesized perovskite materials had the nominal compositions of LaCoO3, LaCo0.8Cu0.2O3, La0.8Sr0.2Co0.8Cu0.2O 3, and La0.8M0.2FeO3 (where M = Ce and Sr). The catalytic activity of the perovskite samples (for low-temperature CO oxidation) was measured using a quartz reactor with an inlet gas mixture containing 97% N2, 1% O2, and 2% CO. The prepared perovskite samples were characterized by SEM, nitrogen adsorption (BET), XRF, and XRD analyses. The perovskite catalysts showed good structural and chemical stability up to 600 °C and high activity for the catalytic CO oxidation...
Carbonaceous supports decorated with Pt–TiO2 nanoparticles using electrostatic self-assembly method as a highly visible-light active photocatalyst for CO2 photoreduction
, Article Renewable Energy ; Volume 145 , January , 2020 , Pages 1862-1869 ; Khorasheh, F ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Supported Pt–TiO₂ photocatalysts on carbonaceous supports were synthesized by the electrostatic self-assembly method to study CO₂ photoreduction to produce CH₄. Catalytic activities of the prepared photocatalysts were correlated with the particle size and dispersion of the active metal, which in turn depended on the type of carbonaceous support used, varying in the order of multi-walled carbon nanotubes (MWCNT) > Single-walled carbon nanotubes (SWCNT) > reduced graphene oxide > activated carbon. Generally, all catalysts were highly photoresistant with less than 5% loss of activity in terms of CH₄ yield. Pt–TiO₂/multi-walled carbon nanotubes exhibited better catalytic activity compared with...
Mössbauer and magnetic studies of iron-zeolite and iron-cobalt zeolite catalysts used in synthesis gas conversion
, Article International Journal of Engineering, Transactions B: Applications ; Volume 20, Issue 3 , 2007 , Pages 263-274 ; 1728-144X (ISSN) ; Lo, C ; Sharif University of Technology
Materials and Energy Research Center
2007
Abstract
Medium-pore (diameter - 6A) zeolites such as ZSM-5 and silicalite impregnated with Group VIII metals provide selective catalytic pathways for the conversion of synthesis gas to gasoline or olefins. Mössbauer and magnetic studies on these catalysts containing iron or iron plus cobalt are reported. The zeolites were impregnated with metal nitrate solutions, reduced, and carbided to yield showed Fe3+ type spectra. The ZSM-5 (14.7 % Fe) and Silicalite (13.6 % Fe) samples exposed to H2 (450 C) showed an approximate 85% reduction to the metallic state. The carbided ZSM-5 (14.7 % Fe) revealed a spectrum of Hagg carbide (Fe5C2), an active component of the catalyst. The used catalysts showed mixtures...
Sustainable ammonia production from steam reforming of biomass-derived glycerol in a heat-integrated intensified process: Modeling and feasibility study
, Article Journal of Cleaner Production ; Volume 324 , 2021 ; 09596526 (ISSN) ; Lotfi Varnoosfaderani, M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Currently, ammonia, as a clean and sustainable energy carrier, is intensively synthesized from its elements during the Haber-Bosch technology. This process requires a large amount of energy and emits numerous amounts of carbon dioxide, because hydrogen is dominantly produced from fossil fuels through reforming processes. Biomass-derived glycerol steam reforming is an attractive alternative to traditional reforming for reducing the dependence on hydrocarbon resources and mitigating climate change. This research aims to intensify a heat-integrated process for the co-production of ammonia and syngas from glycerol valorization. In this process, glycerol reforming continuously provides hydrogen...
Catalytic conversion of bio-renewable glycerol to pure hydrogen and syngas: Energy management and mitigation of environmental pollution
, Article Energy Conversion and Management ; Volume 247 , 2021 ; 01968904 (ISSN) ; Lotfi Varnoosfaderani, M ; Moghadasin, M. H ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Hydrogen and syngas, as two effective clean fuels, have a considerable stake in the global fuel market. These are dominantly produced from fossil fuels through reforming processes, which lose a large amount of energy and emit numerous amounts of CO2. Bio-renewable glycerol steam reforming is an attractive alternative to traditional reforming for reducing the dependence on hydrocarbon resources and mitigating climate change. This research aims to manage a heat-integrated reactor with three concentric cylinders, containing exothermic-side (methane tri-reforming), endothermic-side (glycerol steam reforming), and permeation-side for co-production of pure hydrogen and syngas. In this process,...
Detailed analysis of the effects of biodiesel fraction increase on the combustion stability and characteristics of a reactivity‐ controlled compression ignition diesel‐biodiesel/natural gas engine
, Article Energies ; Volume 15, Issue 3 , 2022 ; 19961073 (ISSN) ; Hosseini, V ; Sharif University of Technology
MDPI
2022
Abstract
A single‐cylinder marine diesel engine was modified to be operated in reactivity controlled compression ignition (RCCI) combustion mode. The engine fueling system was upgraded to a common rail fuel injection system. Natural gas (NG) was used as port fuel injection, and a die-sel/sunflower methyl ester biodiesel mixture was used for direct fuel injection. The fraction of bio-diesel in the direct fuel injection was changed from 0% (B0; 0% biodiesel and 100% diesel) to 5% (B5) and 20% (B20) while keeping the total energy input into the engine constant. The objective was to understand the impacts of the increased biodiesel fraction on the combustion characteristics and stability, emissions, and...
Predicting hourly air pollutant levels using artificial neural networks coupled with uncertainty analysis by Monte Carlo simulations
, Article Environmental Science and Pollution Research ; Volume 20, Issue 7 , 2013 , Pages 4777-4789 ; 09441344 (ISSN) ; Kamali, N ; Rajabi, M. M ; Sharif University of Technology
2013
Abstract
Recent progress in developing artificial neural network (ANN) metamodels has paved the way for reliable use of these models in the prediction of air pollutant concentrations in urban atmosphere. However, improvement of prediction performance, proper selection of input parameters and model architecture, and quantification of model uncertainties remain key challenges to their practical use. This study has three main objectives: to select an ensemble of input parameters for ANN metamodels consisting of meteorological variables that are predictable by conventional weather forecast models and variables that properly describe the complex nature of pollutant source conditions in a major city, to...
Fischer-tropsch synthesis: development of kinetic expression for a sol-gel Fe-Ni/Al 2O 3 catalyst
, Article Fuel Processing Technology ; Volume 97 , May , 2012 , Pages 130-139 ; 03783820 (ISSN) ; Fazlollahi, F ; Atashi, H ; Mirzaei, A. A ; Hosseinpour, V ; Sharif University of Technology
2012
Abstract
In this experimental study, a kinetic model has been developed for Fischer-Tropsch synthesis reactions by using sol-gel technique and Fe/Ni/Al 2O 3 as the catalyst (40% Fe/60% Ni/40 wt.%Al 2O 3) in a differential fixed-bed micro reactor assuming no internal or external diffusion. Operating conditions of the reactor were as follows: total pressure 1-12 atm; Temperature 220-260 °C; H 2/CO feed ratio 1.5-2; gas hourly space velocity 2100-7000 cm 3(STP)/h/ g cat and conversions of 6-37% of hydrogen and 7-21% of carbon monoxide. Mass transfer limitations were investigated by changing synthesis gas velocity in reactors which differ in size. Based on the hypothesis that water inhibits the intrinsic...