The Experts below are selected from a list of 6966 Experts worldwide ranked by ideXlab platform
Lorenz T. Biegler - One of the best experts on this subject based on the ideXlab platform.
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dynamic reduced order models for simulating Bubbling Fluidized Bed adsorbers
Industrial & Engineering Chemistry Research, 2015Co-Authors: Mingzhao Yu, David C Miller, Lorenz T. BieglerAbstract:Spatially distributed first-principles process models provide an accurate physical description of chemical processes, but lead to large-scale models whose numerical solution can be challenging and computationally expensive. Therefore, fast reduced order models are required for model-based real-time applications, such as advanced process control and dynamic real-time optimization. In this paper, we focus on the model reduction of a Bubbling Fluidized Bed (BFB) adsorber, which is a key component of a postcombustion carbon capture system. From a temporal aspect, dynamic reduced models are generated using the nullspace projection and eigenvalue analysis method, with the basic idea of quasi-steady state approximation for the states with fast dynamics. From a spatial aspect, dynamic reduced models are developed using orthogonal collocation and proper orthogonal decomposition to reduce the size of the rigorous model. Finally, a computationally efficient and accurate dynamic reduced model is developed for the BFB...
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Dynamic Reduced Order Models for Simulating Bubbling Fluidized Bed Adsorbers
Industrial and Engineering Chemistry Research, 2015Co-Authors: Min Yu, D.c. Miller, Lorenz T. BieglerAbstract:Spatially distributed first-principles process models provide an accurate physical description of chemical processes, but lead to large-scale models whose numerical solution can be challenging and computationally expensive. Therefore, fast reduced order models are required for model-based real-time applications, such as advanced process control and dynamic real-time optimization. In this paper, we focus on the model reduction of a Bubbling Fluidized Bed (BFB) adsorber, which is a key component of a postcombustion carbon capture system. From a temporal aspect, dynamic reduced models are generated using the nullspace projection and eigenvalue analysis method, with the basic idea of quasi-steady state approximation for the states with fast dynamics. From a spatial aspect, dynamic reduced models are developed using orthogonal collocation and proper orthogonal decomposition to reduce the size of the rigorous model. Finally, a computationally efficient and accurate dynamic reduced model is developed for the BFB adsorber by combining temporal and spatial model reduction techniques, which is suitable for an online optimization-based control strategy. © 2015 American Chemical Society.
Bo G Leckner - One of the best experts on this subject based on the ideXlab platform.
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numerical simulation of the fluid dynamics of a freely Bubbling Fluidized Bed influence of the air supply system
Powder Technology, 2002Co-Authors: Eric Peirano, Filip Johnsson, Bo G Leckner, V Delloume, Olivier SimoninAbstract:Abstract Numerical simulations, based on an Eulerian approach, of a freely Bubbling Fluidized Bed (BFB) are performed where emphasis is put on the importance of the inlet boundary conditions (influence of the pressure drop of the air distributor on the state of fluidization). The numerical results are compared with local instantaneous pressure measurements and time-averaged measurements (Bed height, mean particle concentration). The closure of the Eulerian model is treated as follows: the drift velocity is modelled with a binary dispersion coefficient, gas-phase (continuous phase) fluctuations are modelled with a modified two-equation k1–ϵ1 model, and particle-phase (discrete phase) fluctuations are also descriBed by a two-equation k2–k12 model derived from the kinetic theory of granular flow (modified to account for the interstitial gas) and a Langevin equation. The numerical computations (of a Bubbling Fluidized Bed) predict qualitatively the experimental values, which shows that there is a coupling between the Bed and the air supply system.
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Bed-to-wall heat transfer in a 10m2 Bubbling Fluidized Bed
1994Co-Authors: Bengt-Åke Andersson, Bo G LecknerAbstract:The heat transfer is measured on the membrane tube wall in contact with a Bubbling Fluidized Bed boiler. Measurements are carried out by heat transfer meters through holes in the wall both in the Bed and above the Bed in the splash zone and freeboard. Heat transfer coefficients are given and compared with previous measurements of material loss at the same wall and under the same conditions (typical for a Fluidized Bed boiler)
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expansion of a freely Bubbling Fluidized Bed
Powder Technology, 1991Co-Authors: Filip Johnsson, Sven B Andersson, Bo G LecknerAbstract:Abstract The expansion of a freely Bubbling Fluidized Bed is studied over a range of particle properties and gas velocities that applies to Fluidized Bed boilers. A Bed expansion model is derived from a modified two-phase flow model. The results from the model are compared with measurements in both a cold two-dimensional Bed and a 16 MW th Fluidized Bed boiler, as well as with data found in the literature. The model represents experimental results for sand particles of a diameter ranging from 0.15 mm to 4.0 mm and with gas velocities up to 3 m s −1 .
David C Miller - One of the best experts on this subject based on the ideXlab platform.
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dynamic reduced order models for simulating Bubbling Fluidized Bed adsorbers
Industrial & Engineering Chemistry Research, 2015Co-Authors: Mingzhao Yu, David C Miller, Lorenz T. BieglerAbstract:Spatially distributed first-principles process models provide an accurate physical description of chemical processes, but lead to large-scale models whose numerical solution can be challenging and computationally expensive. Therefore, fast reduced order models are required for model-based real-time applications, such as advanced process control and dynamic real-time optimization. In this paper, we focus on the model reduction of a Bubbling Fluidized Bed (BFB) adsorber, which is a key component of a postcombustion carbon capture system. From a temporal aspect, dynamic reduced models are generated using the nullspace projection and eigenvalue analysis method, with the basic idea of quasi-steady state approximation for the states with fast dynamics. From a spatial aspect, dynamic reduced models are developed using orthogonal collocation and proper orthogonal decomposition to reduce the size of the rigorous model. Finally, a computationally efficient and accurate dynamic reduced model is developed for the BFB...
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a one dimensional 1 d three region model for a Bubbling Fluidized Bed adsorber
Industrial & Engineering Chemistry Research, 2012Co-Authors: David C MillerAbstract:A general one-dimensional (1-D), three-region model for a Bubbling Fluidized-Bed adsorber with internal heat exchangers has been developed. The model can predict the hydrodynamics of the Bed and provides axial profiles for all temperatures, concentrations, and velocities. The model is computationally fast and flexible and allows for any system of adsorption and desorption reactions to be modeled, making the model applicable to any adsorption process. The model has been implemented in both gPROMS and Aspen Custom Modeler, and the behavior of the model has been verified.
Mohamed Pourkashanian - One of the best experts on this subject based on the ideXlab platform.
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Numerical simulation and experimental validation of the hydrodynamics in a 350 kW Bubbling Fluidized Bed combustor
International Journal of Energy and Environmental Engineering, 2016Co-Authors: Embarek Belhadj, Stephen Chilton, William Nimmo, Hubert Roth, Mohamed PourkashanianAbstract:This paper presents experimentally validated three-dimensional numerical simulation of a 350 kW pilot-scale Bubbling Fluidized Bed combustor, which has been developed by using commercial CFD software package, Fluent 14.5. The solid particle distribution has been simulated by using the multiphase Euler–Euler Approach. The gas–solid momentum exchange coefficients were calculated by using Syamlal and O’Brien drag functions. The CFD model is created as the realistic representation of the actual pilot-scale Bubbling Fluidized Bed. All simulations are performed in transient mode for an operation time of about 350 s. The experimental study is performed with silica sand particles with mean particle size of 0.6 mm and density of 1639 kg/m^3. The Bed was filled with particles up to a height of 0.30 m. The same conditions are used for the simulations. The present work combines both experimental and computational studies, where the CFD-Simulation results are compared to those obtained by experiments. The predicted simulation results of minimum fluidization velocity and pressure drop values of the pilot-scale Bubbling Fluidized Bed combustor have good agreement with the experimental measurements.
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Numerical simulation and experimental validation of the hydrodynamics in a 350 kW Bubbling Fluidized Bed combustor
international journal of energy and environmental engineering, 2016Co-Authors: Embarek Belhadj, Stephen Chilton, William Nimmo, Hubert Roth, Mohamed PourkashanianAbstract:This paper presents experimentally validated three-dimensional numerical simulation of a 350 kW pilot-scale Bubbling Fluidized Bed combustor, which has been developed by using commercial CFD software package, Fluent 14.5. The solid particle distribution has been simulated by using the multiphase Euler–Euler Approach. The gas–solid momentum exchange coefficients were calculated by using Syamlal and O’Brien drag functions. The CFD model is created as the realistic representation of the actual pilot-scale Bubbling Fluidized Bed. All simulations are performed in transient mode for an operation time of about 350 s. The experimental study is performed with silica sand particles with mean particle size of 0.6 mm and density of 1639 kg/m3. The Bed was filled with particles up to a height of 0.30 m. The same conditions are used for the simulations. The present work combines both experimental and computational studies, where the CFD-Simulation results are compared to those obtained by experiments. The predicted simulation results of minimum fluidization velocity and pressure drop values of the pilot-scale Bubbling Fluidized Bed combustor have good agreement with the experimental measurements.
James J Leahy - One of the best experts on this subject based on the ideXlab platform.
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gasification of torrefied miscanthus giganteus in an air blown Bubbling Fluidized Bed gasifier
Bioresource Technology, 2014Co-Authors: Marzena Kwapinska, Alen Horvat, Witold Kwapinski, L P L M Rabou, Stephen Dooley, Krzysztof Czajka, James J LeahyAbstract:Abstract Torrefaction is suggested to be an effective method to improve the fuel properties of biomass and gasification of torrefied biomass should provide a higher quality product gas than that from unprocessed biomass. In this study, both raw and torrefied Miscanthus × giganteus (M × G) were gasified in an air-blown Bubbling Fluidized Bed (BFB) gasifier using olivine as the Bed material. The effects of equivalence ratio (ER) (0.18–0.32) and Bed temperature (660–850 °C) on the gasification performance were investigated. The results obtained suggest the optimum gasification conditions for the torrefied M × G are ER 0.21 and 800 °C. The product gas from these process conditions had a higher heating value (HHV) of 6.70 MJ/m 3 , gas yield 2 m 3 /kg biomass (H 2 8.6%, CO 16.4% and CH 4 4.4%) and cold gas efficiency 62.7%. The comparison between raw and torrefied M × G indicates that the torrefied M × G is more suitable BFB gasification.
