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Full-Text Articles in Chemical Engineering
Flow Rate Of Solids In L-Valves, Duvvuri Subbarao
Flow Rate Of Solids In L-Valves, Duvvuri Subbarao
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
Movement of solids in a L-valve by fluid drag due to external aeration is opposed by frictional resistance at the wall/non-moving solids. Model equations developed for the threshold aeration rate and solids flow rate as a function of aeration rate compare well with the literature data.
Cold Model Investigations Of A High Temperature Looping Process In A Dual Circulating Fluidized Bed System, Ajay R. Bidwe, Miguel A.M Dominguez, Craig Hawthorne, Heiko Dieter, Alexander Charitos, Anjia Schuster, Güenter Scheffknecht
Cold Model Investigations Of A High Temperature Looping Process In A Dual Circulating Fluidized Bed System, Ajay R. Bidwe, Miguel A.M Dominguez, Craig Hawthorne, Heiko Dieter, Alexander Charitos, Anjia Schuster, Güenter Scheffknecht
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
The Calcium Looping process is a promising post-combustion CO2 capture technology. A 200 kWth Dual Circulating Fluidized Bed has been built at IFK, University of Stuttgart. Tests were carried out on a hydrodynamically scaled cold model. Operating parameters have been varied, while the suitability of the 200 kWth design has been proven
Effects Of Particle Properties On Cluster Characteristics In A 2-D Cfb Riser, Jesse Zhu, Jing Xu
Effects Of Particle Properties On Cluster Characteristics In A 2-D Cfb Riser, Jesse Zhu, Jing Xu
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
The characteristic of particle clusters was studied in a 2-D circulating fluidized bed riser by using a digital image system and optical fiber probes. A new parameter, cluster number fraction, was proposed to characterize the clusters. The results indicated the smaller and lighter particles have higher potential to aggregate, while the effects of particle sphericity were less significant than those of particle density and size.
Hydrodynamics Of A Loop-Seal Operated In A Circulating Fluidized Bed: Influence Of The Operating Conditions On Gas And Solid Flow Patterns, Roberto Solimene, Riccardo Chirone, Piero Bareschino, Piero Salatino
Hydrodynamics Of A Loop-Seal Operated In A Circulating Fluidized Bed: Influence Of The Operating Conditions On Gas And Solid Flow Patterns, Roberto Solimene, Riccardo Chirone, Piero Bareschino, Piero Salatino
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
Hydrodynamic features of a loop-seal operated as solids re-injection device in a labscale cold CFB apparatus are studied. Gas flow patterns are characterized by means of gas tracing experiments with continuous injection of CO2 in the loop-seal chambers. Solids flow patterns are characterized by impulsive injection of dyecoloured particles into the supply chamber, followed by particle tracking.
Studies On Propane Dehydrogenation To Propylene In A Gas-Solid-Sold Fluidized Bed Reactor, Yue Chu, Tongwei Wu, Yunxin Li, Zeeshan Nawaz, Yao Wang, Fei Wei
Studies On Propane Dehydrogenation To Propylene In A Gas-Solid-Sold Fluidized Bed Reactor, Yue Chu, Tongwei Wu, Yunxin Li, Zeeshan Nawaz, Yao Wang, Fei Wei
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
Platinum and tin deposited on mixed support of SAPO-34 and alumina oxide at certain proportion constitute a new catalyst of good catalytic performance. The catalyst was tested in a Gas-Solid-Solid fluidized bed reactor. Cold model experiment was carried on to obtain fluidization curves and characteristic velocities. Reaction results in the GSS-FBR showed that propylene yield was improved by 5 % compared with that in micro fixed bed reactor.
Waste Wood Gasification: Distribution Of Nitrogen, Sulphur And Chlorine In A Dual Fluidised Bed Steam Gasifier, Veronika Wilk, C. Aichernig, H. Hofbauer
Waste Wood Gasification: Distribution Of Nitrogen, Sulphur And Chlorine In A Dual Fluidised Bed Steam Gasifier, Veronika Wilk, C. Aichernig, H. Hofbauer
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
Waste wood was gasified in a dual fluidised bed gasifier in order to investigate the behaviour of waste fuels in this technology. The distribution of nitrogen, sulphur and chlorine between the gasifier and combustor of the dual bed system was studied to identify the requirements for gas cleaning devices. The gasification system is suitable for the use of waste wood. A slight adaption of the gas cleaning equipment was necessary compared to gasification of natural woody biomass.
Numerical Simulations Of A Circulating Fluidized Bed With A Square Cross-Section, Tingwen Li, S Pannala, C. Guenther
Numerical Simulations Of A Circulating Fluidized Bed With A Square Cross-Section, Tingwen Li, S Pannala, C. Guenther
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
In this study, both 2D and 3D numerical simulations of a well-documented circulating fluidized bed with a square cross-section were conducted. With some assumptions, a series of 2D simulations was first carried out to study the influence of grid resolution, initial flow field, and boundary condition on the flow hydrodynamics. It was found that 2D simulations under-predicted the solids inventory even with the finest grid (10-particle-diameter grid size). On the other hand, a 3D simulation with relatively coarse grid was found in better agreement with the experimental data. Differences between 2D and 3D simulations were briefly discussed.
Effects Of Gas Velocity And Solid Hold-Up On The Sub-Grid Behavior Of Riser Flows, Christian Costa Milioli, Fernando Eduardo Milioli
Effects Of Gas Velocity And Solid Hold-Up On The Sub-Grid Behavior Of Riser Flows, Christian Costa Milioli, Fernando Eduardo Milioli
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
Two-fluid highly resolved sub-grid simulations (SGS) of riser flows were developed under realistic gas velocities and solid hold-ups, for a solid phase derived from high Stokes number particles. The results showed that both gas velocity and solid hold-up considerably affect the effective hydrodynamics of the solid phase.
Co2 Looping Cycle For Co2 Separation, Tadaaki Shimizu, Takayuki Takahashi, Hiroko Narisawa, Yasuyuki Murakami, Liuyun Li, Heejon Kim
Co2 Looping Cycle For Co2 Separation, Tadaaki Shimizu, Takayuki Takahashi, Hiroko Narisawa, Yasuyuki Murakami, Liuyun Li, Heejon Kim
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
A dual fluidized bed process using CaO-based solid sorbent is considered to be a promising technology to separate CO2 from flue gas with low energy penalty. As reactor for CaO-looping cycle, both bubbling fluidized bed and “fast” fluidized bed are available, thus four possible combinations, (bubbling or fast absorber)x(bubbling or fast regenerator), are conceivable for this process. In this work, the authors discuss favorable combination of reactor type from viewpoints of heat removal from carbonation reactor and on energy penalty associated with dilution of pure oxygen by CO2 in the regenerator. As conclusion, suitable combination was found to be bubbling …
Energetic Optimization Of The Lignin Pyrolysis For The Production Of Aromatic Hydrocarbons, Miika Franck, Ernst-Ulrich Hertge, Stefan Heinrich, Bea Lorenz, Joachim Werther
Energetic Optimization Of The Lignin Pyrolysis For The Production Of Aromatic Hydrocarbons, Miika Franck, Ernst-Ulrich Hertge, Stefan Heinrich, Bea Lorenz, Joachim Werther
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
The energy supply of the endothermic lignin pyrolysis process in a circulating fluidized bed is to be achieved by recirculation of bed material, which is heated by combustion of the by-products char and permanent gases in a separate combustor. The feasibility of this concept is examined by the investigation of the yield of the byproducts in pyrolysis experiments, char combustion kinetics, the pyrolysis energy demand and the combustion energy of the char and the non-condensable gases. It is shown that the integrated pyrolysis-combustion process is feasible and even produces an energy surplus of 4 MJ/kg raw lignin, which can be …
Effect Of Wall Boundary Conditions And Mesh Refinement On Numerical Simulation Of Pressurized Dense Fluidized Bed For Polymerization Reactor, Pascal Fede, Olivier Simonin, Renaud Ansart, Herve Neau, I. Ghouila
Effect Of Wall Boundary Conditions And Mesh Refinement On Numerical Simulation Of Pressurized Dense Fluidized Bed For Polymerization Reactor, Pascal Fede, Olivier Simonin, Renaud Ansart, Herve Neau, I. Ghouila
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
The effect of the mesh refinement and the solid phase boundary condition are investigated for numerical simulation of dense pressurized fluidized bed. Two fluidized beds have been considered: a laboratory-scale device and a pilot-scale facility. A relation is proposed to scale-up the numerical simulation and preserving the spatial resolution accuracy. As expected the boundary condition of the solid phase modifies the behaviour of the fluidized bed. Compared to free-slip wall boundary condition, a no-slip condition improves the numerical predictions with respect to available experimental data.
The Development Of A Novel Cu-Mn Oxygen Carrier For The Chemical Looping Gasification Of Biomass, M. Aghabararnejad, Jamal Chaouki, Gregory S. Patience
The Development Of A Novel Cu-Mn Oxygen Carrier For The Chemical Looping Gasification Of Biomass, M. Aghabararnejad, Jamal Chaouki, Gregory S. Patience
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
Circulating fluidized bed technology applied to combustion processes in which oxygen and fuel are fed into separate reactors is referred to as Chemical Looping Combustion. Typically, oxygen reacts with a reduced metal (-oxide), then it is transferred to a second vessel where the metal oxide is reduced by a hydrocarbon. In chemical looping gasification, a fuel is contacted indirectly by oxygen and/or steam again with a metal oxide shuttling between two vessels reducing the contact between fuel and air. In this case, a concentrated stream of syngas exits the fuel reactor undiluted by nitrogen. The objective of this study is …
High-Resolution Simulations Of Gas-Solids Jet Penetration Into A High- Density Riser Flow, Tingwen Li, C. Guenther
High-Resolution Simulations Of Gas-Solids Jet Penetration Into A High- Density Riser Flow, Tingwen Li, C. Guenther
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
High-resolution simulations of a gas-solids jet in a 0.3 m diameter and 15.9 m tall circulating fluidized bed (CFB) riser were conducted with the open source software-MFIX. In the numerical simulations, both gas and solids injected through a 1.6 cm diameter radial-directed tube 4.3 m above the bottom distributor were tracked as tracers, which enable the analysis of the characteristics of a two-phase jet. Two jetting gas velocities of 16.6 and 37.2 m/s were studied with the other operating conditions fixed. Reasonable flow hydrodynamics with respect to overall pressure drop, voidage, and solids velocity distributions were predicted. Due to the …
A Modeling Study Of Gas Streaming In A Deep Fluidized Bed Of Geldart A Particles, Shayan Karimipour, Todd S. Pugsley
A Modeling Study Of Gas Streaming In A Deep Fluidized Bed Of Geldart A Particles, Shayan Karimipour, Todd S. Pugsley
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
Gas streaming has been modeled in a deep fluidized bed of 5 m depth and 0.3 m inside diameter. The model results suggest that the lower pressure drop of the stream zone compared to the remainder of the bed is the reason for severe streaming flow in deep beds. The effects of different parameters such as bed depth, gas velocity and particle size on the severity of the streaming flow are also evaluated with the model.
Fluidized Bed Membrane Reactor For Steam Reforming Of Higher Hydrocarbons: Model Sensitivity, M.A. Rakib, John R. Grace, C. Jim Lim
Fluidized Bed Membrane Reactor For Steam Reforming Of Higher Hydrocarbons: Model Sensitivity, M.A. Rakib, John R. Grace, C. Jim Lim
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
A fluidized bed membrane reactor (FBMR) was built and operated at temperatures <600°C to reform higher hydrocarbons like propane and heptane. A two-phase reactor model is utilized to simulate the FBMR with hydrogen withdrawn from both phases. The superficial gas velocities in the reactor change because of variations in molar flow due to reaction and hydrogen withdrawal through the membranes, as well as variations in temperature, pressure and cross-sectional area. Sensitivity studies show that the FBMR performance is primarily controlled by chemical equilibrium and hydrogen permeation through the membranes, while being insensitive to errors in accurately characterizing the chemical kinetics and hydrodynamics.
Removal Of Nitrate From Water Using Fluidized Bed Ion Exchange Column, Ammar Arab Beddai, Basava Rao
Removal Of Nitrate From Water Using Fluidized Bed Ion Exchange Column, Ammar Arab Beddai, Basava Rao
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
Experimental and theoretical studies were carried out to investigate the performance of a fluidized bed ion exchange system to remove nitrate. The exchange of nitrate on strong anion exchange resin (TULSION A-27) was studied in the flow rate range of 2 to 7 L/h. Nitrate removal was done at five conditions of the expanded bed height (Z). The results showed that the experimental data can be fitted to Richardson and Zaki equation, and the comparison between the experimental and calculated terminal velocities showed low relative error
Production Of Gasoline And Gaseous Olefins By Catalytic Cracking Of Pyrolysis Oil, Peter Bielansky, Alexander Reichhold, Alexander Weinert
Production Of Gasoline And Gaseous Olefins By Catalytic Cracking Of Pyrolysis Oil, Peter Bielansky, Alexander Reichhold, Alexander Weinert
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
Co-processing of biomass in petroleum refineries is a promising approach for biofuel production. In this work fluid catalytic cracking of residue from a co-pyrolysis with sawdust and VGO (1:2) was investigated. The pyrolysis oil residue with a boiling range bigger than 350 °C was mixed in different ratios with VGO and could be processed successfully up to 20 m%. Crack gas amounts increased while gasoline and total fuel yields decreased compared to VGO cracking. The gasoline obtained has a high octane number and is oxygen free.
Fluid Dynamic Effects Of Ring- Type Internals In A Dual Circulating Fluidized Bed System, D.C Guio-Perez, K. Marx, Tobias Pröll, Hermann Hofbauer
Fluid Dynamic Effects Of Ring- Type Internals In A Dual Circulating Fluidized Bed System, D.C Guio-Perez, K. Marx, Tobias Pröll, Hermann Hofbauer
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
Intensified gas-solids contact in the fuel reactor of chemical looping combustion systems can be a key issue for achieving the necessary gas-phase conversion rates. Wedge-shaped rings were designed and installed in the fuel reactor of a cold flow model for fluid dynamic testing. These internals are meant to reduce the typical radial and axial solids concentration non-uniformity. It is shown, that more solids are present in the upper regions of the riser when in-ternals are used. Additionally, increase of the solids elutriation rate from the riser was found
A Practical Model For A Dense- Bed Countercurrent Fcc Regenerator, Yongmin Zhang, Chunxi Lu
A Practical Model For A Dense- Bed Countercurrent Fcc Regenerator, Yongmin Zhang, Chunxi Lu
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
In this study, a new practical countercurrent regenerator model for in-situ FCC operation optimization was proposed. A three-zone-and-two-phase gas model and a new two-CSTR-with-interchange model were used to give better descriptions on the gas and solids flow patterns, addressing the region-dependent mass transfer rates and the freeboard effect on catalyst regeneration. The model coupled mass and heat balances, hydrodynamics and reaction kinetics. The modeled results are in reasonable agreement with the commercial data from an industrial FCC regenerator under both partial and full CO combustion modes.
Study Of Calcination-Carbonation Of Calcium Carbonate In Different Fluidizing Mediums For Chemical Looping Gasification In Circulating Fluidized Beds, Prabir Basu, Bishnu Achayra, Animesh Dutta
Study Of Calcination-Carbonation Of Calcium Carbonate In Different Fluidizing Mediums For Chemical Looping Gasification In Circulating Fluidized Beds, Prabir Basu, Bishnu Achayra, Animesh Dutta
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
Chemical looping gasification (CLG) of biomass in a circulating fluidized bed is an excellent option for production of separate streams of hydrogen rich and carbon dioxide rich gases. This process uses H2O (steam) instead of air or oxygen for gasification, and thereby produces high value nitrogen free product gas. An important feature of this process is in-process removal of carbon dioxide from the reaction site by CaO. This allows the reaction to move towards higher yield of hydrogen. Circulating fluidized bed (CFB) provides an ideal reactor configuration for such a looping reaction. A CFB based CLG unit operates somewhat similar …
The Influence Of Carbon Stripper Efficiency On Co2 Capture Rate In A Chemical-Looping Combustion Process For Solid Fuels, Marvin Kramp, Andreas Thon, Ernst-Ulrich Hartge, Stefan Heinrich, Joachim Werther
The Influence Of Carbon Stripper Efficiency On Co2 Capture Rate In A Chemical-Looping Combustion Process For Solid Fuels, Marvin Kramp, Andreas Thon, Ernst-Ulrich Hartge, Stefan Heinrich, Joachim Werther
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
In the present work a Chemical-Looping Combustion process for solid fuels is simulated on the 100 MWth scale. The coal is gasified inside the fuel reactor by recirculated CO2 and H2O. A carbon stripper downstream of the fuel reactor is used to reduce the carryover of char from the fuel to the air reactor. The influence of the carbon stripper on the CO2 capture rate is investigated. The results demonstrate the significance of the carbon stripper in this process.
Understanding Standpipe Hydrodynamics Using Electrical Capacitance Tomography, Reddy Karri Dr, Changhua Qui, Robert Joachim S.B
Understanding Standpipe Hydrodynamics Using Electrical Capacitance Tomography, Reddy Karri Dr, Changhua Qui, Robert Joachim S.B
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
Standpipes are often the bottleneck in a circulating fluidized bed processes. Understanding the pressure build and dissipation in a standpipe is critical in designing and operating a standpipe that can meet production needs. However, this critical component of a circulating fluidized bed (CFB) is often neglected in the design process which usually results in an underperforming unit operation. In an effort to better design new standpipe and to better optimize existing ones, electrical capacitance tomography (ECT) was evaluated in a 7-inch (18-cm) diameter standpipe to understand the gas-solid hydrodynamics in a standpipe with respect to circulation rates and aeration strategies.
Simulation Of Particle-Gas Flow In A Cyclone Using Urans, Aku Karvinen, Hannu Ahlstedt, Marko Palonen
Simulation Of Particle-Gas Flow In A Cyclone Using Urans, Aku Karvinen, Hannu Ahlstedt, Marko Palonen
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
Particle-gas flow in a cyclone separator used in a circulating fluidized-bed boiler is simulated using computational fluid dynamics software Fluent 6.2.36 and an Unsteady Reynolds-Averaged Navier-Stokes (URANS) method. A Lagrangian method is used for particle simulation and a one-way coupling between particles and gas is assumed. The effect of the turbulence model is studied using several turbulence models. Only the Reynolds stress model gives a physically reasonable flow field without adjusting parameters unknown beforehand.
Design Requirements For Pressurized Chemical Looping Reforming, Tobias Pröll, Hermann Hofbauer, K. Marx
Design Requirements For Pressurized Chemical Looping Reforming, Tobias Pröll, Hermann Hofbauer, K. Marx
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
A key issue in chemical looping reforming is to operate the process under pressurized conditions. Applicability of dual fluidized bed systems, currently used in atmospheric chemical looping processes, is affected by pressure. Critical design issues were studied and experimentally verified by cold flow model experiments. It turns out that it is important to achieve sufficient global solids circulation and to keep the pressure difference between the reactors low enough for proper operation of the loop seals.
Flow Field In A Novel Short Residence Time Gas-Solid Separator, Mengxi Liu, Chunxi Lu, Zhuan Wang
Flow Field In A Novel Short Residence Time Gas-Solid Separator, Mengxi Liu, Chunxi Lu, Zhuan Wang
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
The gas flow field in a short residence time separator was investigated. The tangential velocity in the separator housing increases with increasing angle to the positive x axis, and decreases with increasing radial position. A swirl of opposite direction to the main current in the separator housing occurs in the gas outlet.
Cold Flow Model Study On Interconnected Fluidized Bed Reactors For Multi-Generation Systems And Chemical Looping Processes, Georgy A. Ryabov, O M. Folomeyev, D A. Sankin, K V. Khaneyev
Cold Flow Model Study On Interconnected Fluidized Bed Reactors For Multi-Generation Systems And Chemical Looping Processes, Georgy A. Ryabov, O M. Folomeyev, D A. Sankin, K V. Khaneyev
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
Interconnected fluidized bed reactors (DCFB) were implemented in multi-generation systems (pyrolysis FB reactor and CFB boiler), chemical looping combustion (CLC) systems (double metal oxides or carbonate oxide reactors) and three reactor chemical looping gasification processes. The presented data focus on the solids circulation rate and on pressure profiles of the DCFB depended on selected operating parameters such as fluidization gas flow rate, loop seal fluidization, and solids inventory. Most work was devoted to studying standpipe and valve operation.