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2011

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Articles 2221 - 2250 of 5805

Full-Text Articles in Engineering

Comprehensive Analysis Of Effluent Organic Matter From Five Wastewater Treatment Plants In Connecticut And Comparison To Natural Organic Matter, Matthew L. Quaranta May 2011

Comprehensive Analysis Of Effluent Organic Matter From Five Wastewater Treatment Plants In Connecticut And Comparison To Natural Organic Matter, Matthew L. Quaranta

Master's Theses

Natural organic matter is an important driver of biotic and abiotic processes in aquatic environments. Wastewater treatment plants discharge a substantial amount of organic matter into the environment; however effluent organic matter has not been well studied. In this study, traditional organic geochemical techniques were applied to characterize effluent organic matter. Effluent organic matter was isolated by DAX8 (hydrophobic fraction) and XAD4 (transphilic fraction) Amberlite resins. Extraction efficiencies of effluent organic matter by DAX8 resins ranged from 18 to 42 percent as a result of larger content of hydrophilic organic matter than natural organic matter. Average organic matter molecular weights …


A Comparative Study Of Total Hemoglobin Measurement Technology: Noninvasive Pulse Co-Oximetry And Conventional Methods, Jared S. Ruckman May 2011

A Comparative Study Of Total Hemoglobin Measurement Technology: Noninvasive Pulse Co-Oximetry And Conventional Methods, Jared S. Ruckman

Master's Theses

Hemoglobin can be measured on a variety of devices using different principles of operation. Noninvasive pulse CO-oximetry represents the latest development in hemoglobin measuring technology. The technology uses principles similar to pulse oximetry to measure total hemoglobin, oxyhemoglobin, reduced oxyhemoglobin, carboxyhemoglobin and methemoglobin. Similar to the introduction of pulse oximetry to the medical field, pulse CO-oximetry has been met with skepticism. Since the technology is noninvasive and provides continuous monitoring in comparison to invasive and discrete techniques used in other methods, CO-oximetry purportedly provides an advantage in patient care. The purpose of this research is threefold: (a) to review the …


The Use Of Motion Analysis Technology As An Alternative Means Of Assessing Spinal Deformity In Patients With Adolescent Idiopathic Scoliosis, Matthew J. Solomito May 2011

The Use Of Motion Analysis Technology As An Alternative Means Of Assessing Spinal Deformity In Patients With Adolescent Idiopathic Scoliosis, Matthew J. Solomito

Master's Theses

Adolescent Idiopathic Scoliosis (AIS) is a three dimensional deformity of the spine that causes abnormal curvatures in the coronal and sagittal planes and abnormal vertebral rotations. The gold standard for diagnosing and tracking the progression of the deformity is through the use of repeated radiography and a patient can receive upwards of fifteen radiographic series over the course of treatment, which exposes this population to an increased risk of radiation-dependent complications.

This thesis presents the necessary calculations and the marker set required to make the motion capture technology a viable alternative to radiographs, in an effort to reduce the patient’s …


Design Of A Pragmatic Test Lab For Evaluating And Testing Wireless Medical Devices For Deployment On An Integrated It Wireless Network, Allie Paquette May 2011

Design Of A Pragmatic Test Lab For Evaluating And Testing Wireless Medical Devices For Deployment On An Integrated It Wireless Network, Allie Paquette

Master's Theses

In today’s healthcare environment, networking of medical devices is becoming more and more prevalent. There is an increasing need for mobile technology to meet clinical needs. Wireless communication is essential for allowing medical devices to be able to move with the patient, while continuing to record and communicate patient data. A traditional example is telemetry monitoring, but other examples of wireless utilization include sending ECG test results to the EMR or remotely updating the drug library on numerous IV pumps. Each wireless application has varying demands on the connectivity infrastructure and will share radio frequency (RF) spectrum resources with a …


Characterization And Implementation Of Low Intensity Pulsed Ultrasound As A Tool To Apply Physical Load To Scaffolds And Bone Cells For Fracture Repair, Scott Frazee May 2011

Characterization And Implementation Of Low Intensity Pulsed Ultrasound As A Tool To Apply Physical Load To Scaffolds And Bone Cells For Fracture Repair, Scott Frazee

Master's Theses

One current challenge in treating bone fractures is the effective treatment of non-unions and delayed unions. Low Intensity Pulsed Ultrasound (LIPUS) has been approved by the FDA to treat fresh fractures since 1994 and non-unions since 2000 and is an attractive treatment option because it is non-invasive. The mechanism by which it works, however, is not well understood; what is known is largely confined to the resultant changes in chemical output of cells. In this thesis several concepts and techniques were brought together to investigate the following hypothesis: LIPUS produces a measurable physical load that results in measurable deformation and …


Wired For Business: The Roebling Story., Kelley Marie Hatch-Draper May 2011

Wired For Business: The Roebling Story., Kelley Marie Hatch-Draper

Electronic Theses and Dissertations

John Augustus Roebling, a classically educated civil engineer and young Hegelian, immigrated to America in 1831 in search of freedom from a repressive political system that afforded him no opportunity for advancement. Arriving in the midst of the American market revolution, his dream of establishing an agrarian farming colony changed in response to societal transformations resulting from mechanization and the rise of industry. Within forty years, Roebling achieved fame as a canal engineer and bridge designer while establishing the American wire rope industry. Without Roebling's innovation in wire-rope, modern suspension bridges, high-rise elevators, construction cranes, and cable cars would not …


Recording Of Elevated Temperature Fatigue Crack Growth Data By Dcpd System, N. Ramachandran, N. Arakere, Tarun Goswami May 2011

Recording Of Elevated Temperature Fatigue Crack Growth Data By Dcpd System, N. Ramachandran, N. Arakere, Tarun Goswami

Biomedical, Industrial & Human Factors Engineering Faculty Publications

The growth of "long" fatigue cracks, in α-β titanium alloy forging, subjected to cyclic stresses, is studied in this paper. The fatigue crack growth rate (FCGR) data were recorded at room temperature, 350, 450, 550 and 650°F using the Direct Current Potential Difference (DCPD) technique. The DCPD method, used in this investigation, was found to record and correlate the potential difference in terms of crack growth rate (da/dN) and Mode I stress intensity factor range satisfactorily. Various factors related to error minimization and calibration equations for compact tension specimens have been elaborated. Also discussed were the means to enhance the …


Campus Grids: A Framework To Facilitate Resource Sharing, Derek J. Weitzel May 2011

Campus Grids: A Framework To Facilitate Resource Sharing, Derek J. Weitzel

School of Computing: Dissertations, Theses, and Student Research

It is common at research institutions to maintain multiple clusters. These might fulfill different needs and policies, or represent different owners or generations of hard- ware. Many of these clusters are under utilized while researchers at other departments may require these resources. This may be solved by linking clusters with grid mid- dleware. This thesis describes a distributed high throughput computing framework to link clusters without changing security or execution environments. The framework initially keeps jobs local to the submitter, overflowing if necessary to the campus, and regional grid. The framework is implemented spanning two campuses at the Holland Computing …


Comparison Of Entrainment Rate In Acrylonitrile Reactors Using Plant Data And Cfd Simulations, S. Moffatt, S. Ramchandran, P. Zhao, K. Williams May 2011

Comparison Of Entrainment Rate In Acrylonitrile Reactors Using Plant Data And Cfd Simulations, S. Moffatt, S. Ramchandran, P. Zhao, K. Williams

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Accurate entrainment rates are important in fluidized bed reactors for several reasons, including determination of cyclone loadings and efficiencies, sizing of diplegs, and inputs to population balance models. Entrainment correlations exist in the literature and from other sources to predict entrainment rates from fluidized beds, but they can vary by orders of magnitude. In addition, many correlations do not take into account effects of internals which are present in many types of industrial reactors. A study was undertaken to better understand entrainment rates from Sohiotype acrylonitrile fluidized bed reactors containing catalyst classified as a Geldart type A powder. As part …


Cfd Simulation Of Co2 Sorption In A Circulating Fluidized Bed Using Deactivation Kinetic Model, Emadoddin Abbasi, Hamid Arastoopour May 2011

Cfd Simulation Of Co2 Sorption In A Circulating Fluidized Bed Using Deactivation Kinetic Model, Emadoddin Abbasi, Hamid Arastoopour

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

The Computational Fluid Dynamics (CFD) approach was used to simulate sorption of CO2 using solid sorbents in the riser section of a circulating fluidized bed. The simulation results were compared with the experimental data of Korea Institute for Energy Research (KIER) for continuous CO2 sorption using potassium carbonate in a circulating fluidized bed system.


Critical Evaluation Of Euler-Euler And Euler-Lagrangian Modelling Strategies In A 2-D Gas Fluidized Bed, F. Hernández-Jiménez, J. R. Third, A. Acosta-Iborra, C. R, Müller May 2011

Critical Evaluation Of Euler-Euler And Euler-Lagrangian Modelling Strategies In A 2-D Gas Fluidized Bed, F. Hernández-Jiménez, J. R. Third, A. Acosta-Iborra, C. R, Müller

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Two-phase granular systems are commonly encountered in industry, and fluidized beds are particularly important due to their excellent heat and mass transfer characteristics. Here, we critically evaluate the differences between two modelling strategies, Euler-Euler and Euler-Lagrangian models. Euler-Euler simulations were performed using MFIX and an in-house code was used for Euler-Lagrangian simulations. A 2D bed of width, height and transverse thickness of respectively, 0.2 m, 0.5 m and 0.01 m, served as a test case. The settled bed height was H0 = 0.2 m. Particles of density ρ = 1000 kg/m³ and diameter dp = 1.2 mm were fluidized with …


Particle-Fluid Flow Simulations Of An Fcc Regenerator, Sam Clark May 2011

Particle-Fluid Flow Simulations Of An Fcc Regenerator, Sam Clark

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

A particle-fluid flow simulation of a commercial-scale fluidized catalytic cracking unit has been conducted. The simulation was full-scale, three-dimensional, and with complex internal geometries. The focus of the computational model was to predict wear on internal structures. The geometry of the particle feed pipe was found to cause asymmetric flow of high-speed gas which led to significant wear.


Time-Resolved X-Ray Tomography Of A Fluidized Bed Of Geldart A Particles, Robert Frank Mudde, Evert C. Wagner, J.R. Van Ommen, Q. Ricoux May 2011

Time-Resolved X-Ray Tomography Of A Fluidized Bed Of Geldart A Particles, Robert Frank Mudde, Evert C. Wagner, J.R. Van Ommen, Q. Ricoux

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

This paper discusses the influence of fines on the size of bubbles moving through a 23 cm ID fluidized bed of Geldart A particles imaged with an X-ray Tomographic Scanner. In earlier work [1], the bubble distribution in a fluidized bed of Geldart B particles was shown. The current study using Geldart A particles is more challenging to the reconstruction algorithm, since there are more bubbles, and they are smaller in size. We study the influence of adding fines (i.e. particles <= 45 micron) to the system. When adding a mass fraction of fines of 24%, we find a decrease of the average bubble of 40% of the size for the original powder, in line with earlier results from pressure probes and optical probes [2]. We find that the entire distribution of the bubble sizes shifts to smaller values.


A Study Of Solids And Gas Mixing In A Partitioned Fluidized Bed, Young-Ju Seo, Solim Kang, Seung-Yong Lee, Young Cheol Park, Ho-Jung Ryu, Gyoung Tae Jin, Jong-Ho Moon May 2011

A Study Of Solids And Gas Mixing In A Partitioned Fluidized Bed, Young-Ju Seo, Solim Kang, Seung-Yong Lee, Young Cheol Park, Ho-Jung Ryu, Gyoung Tae Jin, Jong-Ho Moon

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

A partitioned fluidized bed gasifier has been developed for improving coal gasification performance. The basic concept is to divide a fluidized bed into two parts, a gasifier and a combustor, by a partition. Char is burnt in the combustor and generated heat is supplied to the gasifier by solid mixing. Therefore, solid mixing should be maximized whereas gas mixing between syngas and the combusted gas should be minimized. In this study, gas and solid mixing behaviors were verified in cold model acrylic beds. For monitoring solid mixing behavior, transient temperature trends in the beds were analyzed. A heat source and …


Cfd Modeling Of Fluidized Bed Reactor For The Synthesis Of Dimethyl Ether, Ranjeeth Kalluri, Nandita Akunuri, Aqil Jamal, Raghubir Gupta May 2011

Cfd Modeling Of Fluidized Bed Reactor For The Synthesis Of Dimethyl Ether, Ranjeeth Kalluri, Nandita Akunuri, Aqil Jamal, Raghubir Gupta

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

The syngas-to-DME reaction is highly exothermic, and the catalyst temperature window is very narrow. The fluidized-bed reactor is, therefore, an ideal choice to carry out these reactions. RTI is developing a circulating fluidized bed design for DME synthesis. This paper discusses a two-phase CFD model and optimization of the solids circulation rate.


A New Approach For Modeling Of A Fluidized Bed By Cfd-Dem, Shayan Karimipour, Navid Mostoufi, Rahmat Sotudeh-Gharebagh, H. Chizari May 2011

A New Approach For Modeling Of A Fluidized Bed By Cfd-Dem, Shayan Karimipour, Navid Mostoufi, Rahmat Sotudeh-Gharebagh, H. Chizari

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Numerical studies of 3D cylindrical fluidized bed by means of combined computational fluid dynamics (CFD) and discrete element method (DEM) were carried out. For motion of particles, Newton's second law and 3D compressible Navier-Stokes equations in generalized curvilinear coordinates in its conservative form were used. Navier-Stokes equations were solved with high order compact finite difference scheme by fully implicit flux decomposition method. Non-reflecting boundary conditions (NRBC) were used for the outflow boundary. The convergence of this method, especially at high Reynolds number, is significantly better than the SIMPLE method.


Description Of Pressure Fluctuations In A Circulating Fluidized Bed By Statistical Analysis, Adam Luckos, Roelof Coetzer, Andre Mostert May 2011

Description Of Pressure Fluctuations In A Circulating Fluidized Bed By Statistical Analysis, Adam Luckos, Roelof Coetzer, Andre Mostert

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

In this paper we evaluate different methods for statistically analyzing the variability in pressure fluctuations measured at three locations in an 80-mm-ID, 5-m-tall CFB model operated with natural rutile particles and air at ambient conditions. The methods evaluated are the Shannon entropy, Fischer information matrix together with kernel density estimation, and an estimation of the magnitude of the pressure amplitudes. The accuracy of the different methods is estimated by the bootstrap method. We illustrate how informative statistics from these methods can be used to quantify the effect of the process variables on fluidization at different bed locations. Depending on the …


Characterization Of Fluidization And Mixing Of Binary Mixtures Containing Biomass At Low Velocities Through Analyzing Local Pressure Fluctuations, Farzam Fotovat, Jaber Shabanian, Jamal Chaouki, Jeffrey Bergthorson May 2011

Characterization Of Fluidization And Mixing Of Binary Mixtures Containing Biomass At Low Velocities Through Analyzing Local Pressure Fluctuations, Farzam Fotovat, Jaber Shabanian, Jamal Chaouki, Jeffrey Bergthorson

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

To judge qualitatively the effect of biomass properties on its fluidizability and mixing tendency with sand particles at low fluidization velocities, local pressure gradients in the top and bottom of the bed were compared for all investigated systems. It was found that changing the mass fraction and the size of biomass impacted the onset of bubbling and the size of bubbles across the bed, which, in turn, affected the mixing/segregation of the bed content.


Dynamics Of Gas-Solids Fluidized Beds Through Pressure Fluctuations: A Brief Examination Of Methods Of Analysis, Srdjan Sasic, Marc-Oliver Coppens, Filip Johnsson, J. Ruud Van Ommen, John Van Der Schaaf, Stefan Gheorghiu May 2011

Dynamics Of Gas-Solids Fluidized Beds Through Pressure Fluctuations: A Brief Examination Of Methods Of Analysis, Srdjan Sasic, Marc-Oliver Coppens, Filip Johnsson, J. Ruud Van Ommen, John Van Der Schaaf, Stefan Gheorghiu

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

This paper revisits and critically examines a number of methods used for analysis of in-bed pressure signals recorded in gas-solid fluidized beds. The goal is to obtain information on the time scales of dominant phenomena present in the pressure time series of four fluidization regimes. It is demonstrated that the average cycle time represents an effective alternative to spectral analysis. In addition, we give evidence that the average cycle time yields equivalent information as some of the advanced methods of non-linear analysis (e.g. the Kolmogorov entropy). Finally, by using wavelets and wavelet packets, we show how to obtain an accurate …


Dynamic Characteristics Of Bubbling And Turbulent Fluidization Using Hurst Analysis Technique, H. Azizpour, Navid Mostoufi, Reza Zarghami, Rahmat Sotudeh-Gharebagh May 2011

Dynamic Characteristics Of Bubbling And Turbulent Fluidization Using Hurst Analysis Technique, H. Azizpour, Navid Mostoufi, Reza Zarghami, Rahmat Sotudeh-Gharebagh

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

A non-intrusive vibration monitoring technique was used to study the flow behavior in a fluidized bed. This technique has several advantages compared to other techniques, such as pressure probes and optical fiber probes which may influence the measurement because they are intrusive. Experiments were conducted in a 15 cm diameter by 2 m tall fluidized bed using 470 micron sand particles. Auto correlation functions, mutual information function and Hurst exponent analyses were used to analyze the fluidized bed hydrodynamics near the transition point from bubbling to turbulent fluidization regime. These methods were able to detect the regime transition point using …


Dem Study Of Fluidized Bed Dynamics During Particle Coating In A Spouted Bed Apparatus, Sergiy Antonyuk, Stefan Heinrich, A. Ershova May 2011

Dem Study Of Fluidized Bed Dynamics During Particle Coating In A Spouted Bed Apparatus, Sergiy Antonyuk, Stefan Heinrich, A. Ershova

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

A novel process for coating of spherical aerogel particles in a spouted bed is suggested. Using Discrete Element Method the influence of the density and restitution coefficient of experimentally coated aerogels on the fluidized bed dynamics in the developed apparatus was described.


Ecvt Imaging Of 3-D Flow Structures And Solids Concentration Distributions In A Riser And A Bend Of A Gas-Solid Circulating Fluidized Bed, Fei Wang, Qussai Marashdeh, Liang Shih Fan May 2011

Ecvt Imaging Of 3-D Flow Structures And Solids Concentration Distributions In A Riser And A Bend Of A Gas-Solid Circulating Fluidized Bed, Fei Wang, Qussai Marashdeh, Liang Shih Fan

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Experimental studies using electrical capacitance volume tomography (ECVT) are conducted to examine gas-solid flows in a riser and a bend of a 0.05 m (2 in) ID gas-solid circulating fluidized bed (CFB) system. The quantitative measurements using ECVT are made that illustrate a three-dimensional symmetric core-annulus structure in the riser and a non-centro-symmetric core-annulus structure in the bend. Results on the volume solids holdup distributions in the riser and in the bend at various operating conditions are also obtained.


A Novel P300 Speller With Motor Imagery Embedded In A Traditional Oddball Paradigm., Vaishnavi Karnad May 2011

A Novel P300 Speller With Motor Imagery Embedded In A Traditional Oddball Paradigm., Vaishnavi Karnad

Theses and Dissertations

A Brain Computer Interface (BCI) provides a means, to control external devices, through the electrical activity of the brain, bypassing motor movement. Recent years have seen an increase in the application of P300 cognitive potential as a control and/or communication signal for the motor restoration in paralyzed patients, such as those in the later stages of ALS (Amyotrophic lateral sclerosis). Although many of these patients are in locked-in state i.e. where motor control is not possible, their cognition is known to remain intact. The P300 speller paradigm explored in this study relying on this cognition represented by the P300 peak …


Vapor Transport And Aerosol Dynamics In The Respiratory Airways, Geng Tian May 2011

Vapor Transport And Aerosol Dynamics In The Respiratory Airways, Geng Tian

Theses and Dissertations

Predicting vapor transport and aerosol dynamics in the respiratory airways is important for analyzing both environmental exposure and respiratory drug delivery. A large number of analytical models, computational studies, and experiments on vapor and aerosol transport in the respiratory tract have been conducted previously. However, a number of critical questions remain unanswered. In this study, computational fluid dynamics (CFD) is primarily employed with frequent comparisons to existing and new experimental data sets to address previously unanswered issues related to the transport of vapors and aerosol in the respiratory tract. The three objectives of this study are further described below. Objective …


A Parallel Genetic Algorithm For Placement And Routing On Cloud Computing Platforms, Jacob A. Berlier May 2011

A Parallel Genetic Algorithm For Placement And Routing On Cloud Computing Platforms, Jacob A. Berlier

Theses and Dissertations

The design and implementation of today's most advanced VLSI circuits and multi-layer printed circuit boards would not be possible without automated design tools that assist with the placement of components and the routing of connections between these components. In this work, we investigate how placement and routing can be implemented and accelerated using cloud computing resources. A parallel genetic algorithm approach is used to optimize component placement and the routing order supplied to a Lee's algorithm maze router. A study of mutation rate, dominance rate, and population size is presented to suggest favorable parameter values for arbitrary-sized printed circuit board …


Sulfur Uptake By Limestone-Based Sorbent Particles In Cfbc: The Influence Of Attrition/Fragmentation On Sorbent Inventory And Particle Size Distribution, Fabio Montagnaro, Piero Salatino, Fabrizio Scala, Massimo Urciuolo May 2011

Sulfur Uptake By Limestone-Based Sorbent Particles In Cfbc: The Influence Of Attrition/Fragmentation On Sorbent Inventory And Particle Size Distribution, Fabio Montagnaro, Piero Salatino, Fabrizio Scala, Massimo Urciuolo

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

This paper presents a population balance model aiming at the prediction of sorbent inventory and particle size distribution establishing at steady state in the bed of an air-blown CFBC fuelled with a sulphur-bearing solid fuel. The core of the model is represented by population balance equations on sorbent particles which embody terms expressing the extent/rate of sorbent attrition/fragmentation. The effect of the progress of sulphation on attrition and fragmentation is taken into account by selection of appropriate constitutive equations. Model results are presented and discussed with the aim of clarifying the influence of particle attrition/fragmentation on sorbent inventory and particle …


Putting Structure Into Fluidized Bed – From Concept To Industrial Applications, Fei Wei, Qiang Zhang, Guohua Luo, Weizhong Qian, Yao Wang May 2011

Putting Structure Into Fluidized Bed – From Concept To Industrial Applications, Fei Wei, Qiang Zhang, Guohua Luo, Weizhong Qian, Yao Wang

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Structures of particles, particle agglomerates, distributors, and internals have significantly influence on hydrodynamics and transfer behaviors of the dense gas-solid fluidized bed. For nanomaterial production, the particle surface and their agglomerated structures directly influence the fluidization behaviors; while for coal to chemical process, the distributors, internals play an important role in regime transient, and hydrodynamics. Carbon nanotubes mass production, coal to chemicals process. and fuel production were employed as examples to describe the concept of putting structures into fluidized bed, and then to put these structures into industrial applications.


Study Of Standpipe And Loop Seal Behavior In A Circulating Fluidized Bed For Geldart B Particles, Heiko Dieter, Alexander Charitos, Ajay R. Bidwe, An Wei, Mariusz Zieba May 2011

Study Of Standpipe And Loop Seal Behavior In A Circulating Fluidized Bed For Geldart B Particles, Heiko Dieter, Alexander Charitos, Ajay R. Bidwe, An Wei, Mariusz Zieba

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

The loop seal aeration effect on the supply side has been studied through small scale CFB experimentation. Parameters affected include inventory allocation and entrainment. The gas velocity in the standpipe is influenced by loop seal aeration and riser velocity. Variation in slugging behavior above and below solid downflow velocity of 0.025 m/s is analyzed and discussed here.


Observation Of Flow Regime Transition In A Cfb Riser Using An Ldv, Paul C. Yue, Joseph Mei, Lawrence J. Shadle May 2011

Observation Of Flow Regime Transition In A Cfb Riser Using An Ldv, Paul C. Yue, Joseph Mei, Lawrence J. Shadle

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

The solids flow in a circulating fluidized bed (CFB) riser is often described to have a core-annular structure. For a given superficial gas velocity, at the initial introduction of solids into a riser a flow structure of dilute upflow regime exists. Continuing to increase the solids flow in the riser transitions the flow structure to the core-annular flow regime. However, with further increase of solids flow a condition is reached, depending on the superficial gas velocity, where all the solids across the riser cross section flow upwards, even those at the wall. When the solids flux, solids fraction and gas …


Evolution Of Fcc - Past Present And Future And The Challenges Of Operating A High Temperature Cfb System, Ye-Mon Chen May 2011

Evolution Of Fcc - Past Present And Future And The Challenges Of Operating A High Temperature Cfb System, Ye-Mon Chen

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

The fluid catalytic cracking (FCC) process is one of the most important circulating fluidized bed processes. Although the FCC process has been in commercial operation for over 60 years, the technology continues to evolve in order to meet new challenges, which include processing more difficult feedstock and meeting more stringent environmental regulations. This paper presents selected snap-shots of a few challenges (high temperature erosion, corrosion and emission control) that the FCC process faces today and the new challenges yet to come in the near future.