Study of heat transfer and hydrodynamics in a gassolid. The generation of electrical charges, reported in gassolid fluidized beds for over sixty years, can cause serious problems like wall sheeting in polyolefin reactors, leading to costly shutdown, electrical shock hazards and even explosions. Hydrodynamic modeling of gassolid bubbling fluidization. Oil process is not characterized by conventional three. Many of the early chapters deal with the properties and characteristics of fluidparticle. Gas solid fluidized beds fbs are extensively used in chemical industries since they enhance the heat and mass transfer. Investigation of bubble hydrodynamics in gassolid fluidized beds. In this research, the heat transfer and hydrodynamics of a gassolid fluidized bed reactor. In this research, the heat transfer and hydrodynamics of a gassolid fluidized bed reactor were studied experimentally and computationally. Gasliquid fluidization is defined as an operation in which bed of solid particles are suspended in gas and. Hydrodynamics of gassolid fluidization hydrodynamics of gassolid fluidization lim, k. A multifluid eulerian computational model incorporating the kinetic theory for solid particles was developed and used to simulate the heat conducting gassolid flows in a fluidized bed configuration.
Most of the gassolid fluidization behavior studies that have been reported are for straight cylindrical or columnar fluidized beds, although a considerable portion. Magnetic resonance imaging of gassolid fluidization with. Many of the early chapters deal with the properties and characteristics of fluidparticle transport and contacting. An eulerianeulerian multifluid model and granular kinetic theory were used to simulate fluidization and to capture the complex physics associated therewith. Fluid dynamics of gas solid fluidized beds german gonzalez silva 1, natalia prieto jimenez 1 and oscar fabio salazar state university of campinas brazil 1. Pdf fluidization refers to the contact between a bed of solids and a flow of fluid. The flow characteristics of turbulent fluidized beds, having transient voids and a diffuse bed surface, have not been well defined, and there. Pdf investigating the hydrodynamics of gassolid bubbling. Computational fluid dynamics cfd modeling was used to predict the gas solid hydrodynamics of fluidized beds. Minimum fluidization velocity is one of the most important parameter to design and optimize gassolid fluidized bed performance.
The kfix code, developed originally by rivard and torrey 1977 for gasliquid two phase flow, has been adapted by gidaspow and ettehadieh 1983 and ettehadieh er. In many industrial processes involving gassolid fluidized bed rectors, the addition of a liquid phase significantly alters the hydrodynamics. The bubbling regime is one of the most studied flow regimes in gas solid fluidization. Study of hydrodynamics of gasliquid fluidized beds international. Hydrodynamics studies of gassolid fluidization in non. Gassolid fluidization is a wellestablished technique to suspend or transport particles and has been applied in a variety of industrial processes. Investigating the hydrodynamics of gassolid bubbling fluidization using recurrence plot. Hydrodynamics of gas solid fluidization hydrodynamics of gas solid fluidization lim, k. Investigation on a gassolid fluidized bed hydrodynamics. Simulation of gassolid turbulent fluidized bed hydrodynamic. As is the role of particle clusters in gassolid fast fluidization, gas bubbles characterize the structural heterogeneity of gassolid bubbling fluidization, and their evolution is mainly. Hydrodynamics of gassolid fluidization sciencedirect. The commercial code ansys fluent was used to study twodimensional single. The hydrodynamic behavior of gasliquid solid fluidized bed is a complex subject and one of the most important for basic understanding of certain refinery and.
Request pdf hydrodynamics of gassolid fluidization in tapered beds gas solid fluidization has a wide range of industrial applications like catalytic reactions, combustion, gasification, etc. Further increases in the superficial gas velocity result in complete conveying of all of the particles. Gassolid fluidization has a wide range of industrial applications like catalytic reactions, combustion, gasification, etc. In this study an attempt has been made to broaden the.
The generation of electrical charges, reported in gas solid fluidized beds for over sixty years, can cause serious problems like wall sheeting in polyolefin reactors, leading to costly shutdown, electrical shock hazards and even explosions. Use of an optical probe to study the hydrodynamics of a. This study can be done through the experiment and simulation works. In this study an attempt has been made to broaden the understanding. Hydrodynamics of geldart group a particles in gassolid fluidized beds 515 korean j. The hydrodynamic behavior of gasliquidsolid fluidized bed is a complex subject and one of the most important for basic understanding of certain refinery and petrochemical industrial applications3.
Hydrodynamics of geldart group a particles in gassolid. Monitoring electrostatics and hydrodynamics in gassolid. Computational fluid dynamics simulation of gassolid. Effect of temperature on the hydrodynamics of bubbling gassolid fluidized beds was investigated in this work. Use of an optical probe to study the hydrodynamics of a gassolid fluidized bed. It is well known that hydrodynamics observed in large scale gassolid fluidized beds are different from those observed in smaller scale beds. Experiments were carried out in two fluidized beds of 14 cm. Hydrodynamic regimes ranging from bubbling to fast fluidization are addressed. To fully characterize the hydrodynamics in the fluidized bed, pressure and acoustic measuring techniques were applied to study the behavior of gas bubbles and particles. Hydrodynamic modeling of gassolid bubbling fluidization is of significance to the development of gassolid bubbling reactors since it still remains at the stage of experimental and empirical science. This site is like a library, use search box in the widget to get ebook that you want. Computational fluid dynamics simulation of gas solid. This shows the importance of distributor plate design in designing the fluidized beds.
Computational fluid dynamics and experimental study of the. A unit operation in chemical engineering experimental and theoretical. Gas solid fluidization has a wide range of industrial applications like catalytic reactions, combustion, gasification, etc. Nevertheless, our knowledge of fluidization hydrodynamics is still limited for the design, scaleup and operation optimization of fluidized bed reactors. Experiments and numerical simulations of hydrodynamics in gas. Hydrodynamics of multiple jet systems in a 2d gas solid. During the past three years we have developed a tentative cold bed hydrodynamic model for an idealized fluidized. Because these parameters are set, the choice of a test powder with density.
The introduction of vibration and rotation of the bed, turbulence promoters in a gassolid fluidized bed enhance the fluidization quality by minimizing bubbling, channeling and slugging but the relative demerits of the above technique is the. Wetty an optical probe was used to study the hydrodynamics of a twodimensional gassolid fluidized bed. In this work, we employed a computational fluid dynamics cfdbased model with a eulerian multiphase approach to simulate the fluidization hydrodynamics in biomass gasification processes. Transient gas mixing tests in a gassolid fluidized bed are analyzed with a dispersive plug flow model from the bubbling to the turbulent regime, and with the.
Gas liquid fluidization is defined as an operation in which bed of solid particles are suspended in gas and. D fluidized bed has been investigated experimentally for different bed aspect ratios at. Hydrodynamics of gassolid turbulent fluidized beds request pdf. The most detailed description is the discrete particle model dpm or the lagrangianeulerian framework where the solid phase consists of individual particles interacting with each other and the continuous gas phase. In a number of these applications, there is particle size reduction during the operation leading to severe entrainment and limitation of operating velocity. Scaleup investigation and hydrodynamics study of gassolid. Mar 01, 2016 hydrodynamic study of solid liquid fluidization 1. Study of heat transfer and hydrodynamics in a gassolid fluidized. With such variations in bed hydrodynamics based on particle properties, it would seem tedious to predict particle behavior in a fluidized bed. At u mf, the hydrodynamic drag force on the particles f d, due to the. The effects of static bed heights, position of pressure measuring points, differential and absolute pressure fluctuations on the hydrodynamic behavior of a geldart group a particles in a gassolid fluidized bed were investigated. Hydrodynamics of gassolids bubbling fluidized beds using. A comprehensive experimental study of the hydrodynamics of gassolid turbulent fluidized beds is reported for fluid cracking catalyst fcc particles in columns of diameter 0.
Request pdf on jan 1, 2003, naoko ellis and others published hydrodynamics of gassolid turbulent fluidized beds find, read and cite all the research you. Recommended citation salma benzarti, hatem mhiri, herve bournot, and rene occelli, simulation of gassolid turbulent fluidized bed hydrodynamic. Hydrodynamics of gas solid fludized bed computational. Investigation into the hydrodynamics of gassolid fluidized beds.
Gas liquid solid fluidization engineering download ebook. U lmf minimum fluidization velocity varing with superficial gas velocity, liquid velocity, solid particle properties and static bed height in the 310 mm diameter gasliquidsolid microfluidized bed were studied and correlations were suggested. Solid gas ows may be modeled using a combination of lagrangian and eulerian models. If we only take into consideration the processes where the liquid is the continuous phase, two configurations are possible. The bubbling regime is one of the most studied flow regimes in gassolid fluidization. Solidgas ows may be modeled using a combination of lagrangian and eulerian models. The gassolid mixing pattern in a fluidized bed is significantly affected by distributor plates. The introduction of vibration and rotation of the bed, turbulence promoters in a gas solid fluidized bed enhance the fluidization quality by minimizing bubbling, channeling and slugging but the relative demerits of the above technique is the. Information relating to the gas liquid solid semi fluidization is meagre although the technique has excellent potential to be used in chemical reactors for catalytic as well as noncatalytic ones, biochemical process and wastewater treatment. Gridzone particle hydrodynamics and solid circulation in a multiple jet fluidized bed.
This type of fluidization is called fast fluidization. The good mixing of gas solid cannot be reached except by using proper distributor plate orifice arrangement. Introduction fluidization refers to the contact between a bed of solids and a flow of fluid. Air at ambient temperature and pressure was used as the fluidizing medium. The velocity required to start fluidize the particle is called minimum fluidization velocity. Nonintrusive measurement and hydrodynamics characterization. Hydrodynamics of gas solid fludized bed free download as powerpoint presentation. As a result, the solid particles are transformed into a fluidlike. This injection leads to the formation of liquid bridges between particles which create viscous and capillary forces between the particles altering the. Nevertheless, our knowledge of fluidization hydrodynamics is still limited for the design, scaleup and. The ability of recently developed novel electrostatic probes to monitor particle charge density and hydrodynamics in freely bubbling two and threedimensional fluidized beds of glass beads and polyethylene particles is demonstrated.
This minimum fluidization velocity was monitored during investigation with changing factors that affect this velocity. Experiments and numerical simulations of hydrodynamics in. Comparison of simulation results between manual calculation and. Hydrodynamics of gassolid fluidization, international. Computational fluid dynamics cfd modeling was used to predict the gassolid hydrodynamics of fluidized beds. Electrohydrodynamics of gassolid fluidized beds ubc. Hydrodynamics of gas hydrodynamics of gasliquidsolid. Hydrodynamics of gassolid fluidization pdf document. A computational study of the hydrodynamics of gassolid. Schematic diagram showing hydrodynamic regimes of fluidization grace 1986. Minimum fluidization velocity is one of the most important parameter to design and optimize gas solid fluidized bed performance.
Eulerianeulerian simulation of dense solid gas cylindrical. Hydrodynamics of regular particles in a liquidsolid semi. Gas phase hydrodynamics of a gassolid turbulent fluidized bed. The hydrodynamic behavior of gas liquid solid fluidized bed is a complex subject and one of the most important for basic understanding of certain refinery and petrochemical industrial applications3. Hydrodynamic characteristics of gassolid fluidization at. Click download or read online button to get gas liquid solid fluidization engineering book now. The characteristics of this regime were compared with that of the conventional fluidization regime and the transport regime. Hydrodynamics of multiple jet systems in a 2d gas solid fluidized bed. Scaleup investigation and hydrodynamics study of gas. Hydrodynamics of gassolid turbulent fluidized beds. Hydrodynamics of gassolids fluidized bed have been investigated extensively, however, the flow behavior of porous particle like polyethylene is still not well. Particle charge density and bubble properties in the beds were altered by abruptly changing superficial gas velocity or by impulsively adding antistatic. The particles used in this study were 80 micrometer fcc powders and 60 micrometer glass beads. Air was used as the gasifyingfluidizing agent and entered the gasifier at the bottom which subsequently fluidized the solid particles inside the reactor column.
Hydrodynamics of gassolid fluidization in tapered beds. Bubbles coalesce and breakup as fluid flow is increased. Hydrodynamics of gassolid turbulent fluidized beds ubc. A new regime, the three phase circulating fluidization regime, was discovered for the first time. Numerical study on the gassolid hydrodynamics and heat. Computational and experimental study of gassolid fluidized bed hydrodynamics. Fluidization is the process in which the solid particles behave like fluids by injecting a small current of fluid through the bed. Characterization on hydrodynamic behavior in liquid. The flow characteristics of turbulent fluidized beds, having transient voids and a diffuse bed surface, have not been well defined. Proceedings of the asme 2012 fluids engineering division summer meeting collocated with the asme 2012 heat transfer summer conference and the asme 2012 10th international conference on nanochannels, microchannels, and minichannels. Understanding the associated phenomena plays an important role to avoid these problems. Foscolo 1989, most fluidization researchers believe that interparticle forces play an important role for group a powders throughout the bubblefree range and in determining umb. Furthermore, using computational fluid dynami cs cfd, modelbased turbulent. Particle charge density and bubble properties in the beds were altered by abruptly changing superficial gas velocity or by impulsively adding antistatic agent to.