Diffusion and Reaction in Fe-Based Catalyst for Fischer-Tropsch Synthesis Using Micro Kinetic Rate Expressions - new
A. Nanduri, P. L. Mills
Department of Chemical & Natural Gas Engineering, Texas A&M University, Kingsville, TX, USA
Fischer-Tropsch synthesis (FTS) is a highly exothermic polymerization reaction of syngas (CO+H2) in the presence of Fe/Co/Ru-based catalysts to produce a wide range of paraffins, olefins and oxygenates, often known as syncrude. Multi-Tubular Fixed Bed Reactors (MTFBR) and Slurry Bubble Column Reactors (SBCR) are widely employed for FTS processes. The scale-up of MTFBR is complicated by the ...
Modeling Heat and Moisture Transport During Hydration of Cement-Based Materials in Semi-Adiabatic Conditions - new
E. Hernandez-Bautista[1,2], D. Bentz, S. Sandoval-Torres, P. Cano-Barrita
National Institute of Standards and Technology, Gaithersburg, MD, USA
Instituto Politécnico Nacional/CIIDIR Unidad Oaxaca, Oaxaca, México
The process of accelerated curing of pre-cast concrete has a significant importance in the thermal behavior of concrete. A multiphysics model that describes hydration and heat and mass transport in cement based materials was developed. The hydration reactions are described by a maturity function that uses the equivalent time concept, thereby describing the change in the degree of hydration based ...
K. Cluff, L. Saeednia, H. Mehraein , R. Asmatulu
Department of Bioengineering, Wichita State University, Wichita, KS, USA
Department of Mechanical Engineering, Wichita State University, Wichita, KS, USA
Polymeric hydrogel is a promising class of drug delivery systems with the controlled release behavior in the body. In-situ forming hydrogels can be injected into the body as a fluid which forms a gel within the body tissue and improve the efficacy of the drugs. Various polymers have been used as in-situ hydrogel formulations. These polymeric formulations can form gels at body temperature while ...
S.C. Seetharam, D. Jacques
Performance Assessments Unit, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre (SCK•CEN), Mol, Belgium
This paper documents current status in the development of a coupled thermal-hydraulic-chemical-geomechanical numerical suite within COMSOL-MATLAB environment to address soil and concrete applications. The mathematical formulations are based on well-established continuum scale models unifying mass conservation, energy conservation, charge conservation, thermodynamic equilibrium and kinetics and ...
G. Samdani, S. Mahajani, A. Ganesh, P. Aghalayam, R. K. Sapru, D. K. Mathur
Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, India
Indian Institute of Technology Madras, Chennai, India
UCG Group, IRS, ONGC, Chankheda, Ahmadabad
The Thermo- Gravimetric Apparatus (TGA) is often used for kinetics determination. In TGA setup, gasification reaction may be limited by the reach (diffusion) of the gasification agent to the internal surfaces of the char particles. In addition to this, after some time, ash is formed between the bulk of the gas and the upper surface of char. The present modeling exercise is aimed at examining the ...
F.T. Wandschneider, M. Küttinger, P. Fischer, K. Pinkwart, J. Tübke, H. Nirschl
Fraunhofer-Institute for Chemical Technology, Pfinztal, Germany
Karlsruhe Institute for Technology, Karlsruhe, Germany
A two-dimensional stationary model of a vanadium oxygen fuel cell is developed in COMSOL Multiphysics®. This energy storage device combines a vanadium flow battery anode and an oxygen fuel cell cathode. The oxygen reduction reaction generates additional water, leading to a degradation of the catalyst performance over time. A logistic function is introduced to the Butler-Volmer equation in order ...
T. Marin-Alvarado ,
 M4Dynamics, Toronto, ON, Canada
An external library, M4Dlib , has been developed to solve multiphysics problems coupled to solution thermodynamics. This approach extends the local equilibrium concept to multiphysics modeling by incorporating a full Gibbs energy minimization routine at each numerical node to calculate the equilibrium based on global temperature, enthalpy or concentration conditions (Figure 1). The ...
Electro-Chemical Etching & Deposition of a Super Alloy Using Tertiary Current Distribution Method - new
M. Yeoman, R. Damodharan
Continuum Blue Ltd., Ystrad Mynach, UK
The application of super-alloys has grown up in numbers in the industries like aerospace, automotive, nuclear, thermal power plant & medical implants. The initial cost of prototyping and the selection of suitable manufacturing methods & test fixtures made by electrochemical machining (ECM) has proven to be expensive process especially where tolerances are extremely tight on the nanometre scale. ...
D. Lahaye, L. Cheng
DIAM, EEMCS Faculty, TU Delft, The Netherlands
Tsinghua University, Beijing, China
In the production of high quality materials by a heat treatment, it is indispensable to accurately predict the temperature inside the furnaces being employed. In this work we develop a turbulent combustion model for the heat being released by gas burners inside a shaft kiln. Turbulent combustion is the strongly coupled phenomena of the chemically reacting fuel and oxygen in a turbulent flow. ...
A COMSOL Multiphysics®-based Model for Simulation of Methane-Hydrate Dissociation by Injection of Superheated Carbon Dioxide
M. Gharasoo, C. Deusner, N. Bigalke, M. Haeckel
Department of Marine Geosystems, GEOMAR - Helmholtz Centre for Ocean Research, Kiel, Germany
Immense amounts of methane are stored as gas-hydrate deposits in deep layers of marine sediments. This has raised considerable interest to develop strategies for producing natural gas from marine hydrates. One potential production strategy is the injection of supercritical CO2 into methane hydrate-bearing sand layers to release the CH4 as a gas and sequester the CO2 as hydrate. We used COMSOL ...