By the 1950s, fluidized bed technology was being applied to mineral and metallurgical processes such as drying, calcining, and sulfide roasting. Also, depending on the degree of fluidization and bed height, these types of reactors sometimes are also named as circulating fluidized bed. They are often used when there is a need for large amounts of heat input or output, or when closely. In this type of reactor, a fluid gas or liquid is passed through a granular solid material usually a catalyst at high enough velocities to suspend the solid and cause it to behave as it were a liquid. To achieve good fluidization, the catalyst particle size was kept between 70 and 120 microns. Fluidized bed reactor chemical processes chemical reactor. A fluidized bed reactor was designed and constructed for practical demonstration of the fluidization of solid particles at different fluid flow rates.
Ray cocco has been with psri for eight years where he has the role of president and ceo. This is to certify that the thesis entitled fluidized bed reactor. Parr fluidized bed reactors are used extensively in the chemical process industries. Packed bed situations include such diverse processes as filtration, wastewater treatment, and the flow of crude oil in a petroleum reservoir. For circulating fluidized bed reactors, biomass particles are introduced into a circulating fluidized bed of hot sand. This is usually achieved by the introduction of pressurized fluid through the particulate medium. Fundamentals of fluidizedbed chemical processes presents a survey of the design, operation, and chemical processes of fluidizedbed reactors. In a fluidized bed boiler, hot air is blown at a high velocity up through a bed of sand, limestone, and ash causing the solid.
Gas extraction ports are evenly distributed along the height of the reactor to extract product gases and accommodate thermocouples for temperature measurement. The distinguishing feature of a fluidized bed reactor is that the bed of solid particles or catalyst is supported by an up flow of gas. Chemical engineering laboratory 3, ce 427 packed and fluidized bed experiment introduction packed and fluidized beds play a major role in many chemical engineering processes. Design, construction, and testing of a fluidized bed reactor. This project presents a specified design of a smallscale fixed bed reactor for the purpose of investigating the gasification processes of biomass and municipal solid wastes. Performance of fixed and fluidized bed reactors with. The first chapter examines the basic physics of gassolid fluidization. A fluidized bed reactor fbr is a type of reactor device that can be used to carry out a variety of multiphase chemical reactions. Fixed bed reactor an overview sciencedirect topics.
Gasification is a process in which combustible materials are partially oxidized or partially combusted. Psri is a consortiumbased company with 35 member companies headquartered in canada, france, brazil, finland, germany, india, south africa, saudi arabia and the united states. A schematic representation of fixed bed reactor is shown in figure 1. Basic design of a fluidized bed reactor for wastewater. Fluidized and fixed bed reactors chemical reactor analysis. University of groningen particle transport in fluidized beds. A fluidized bed is a physical phenomenon occurring when a quantity of a solid particulate substance usually present in a holding vessel is placed under appropriate conditions to cause a solidfluid mixture to behave as a fluid. Stationary or bubbling bed sb circulating fluidized beds cfb vibratory fluidized beds vfb. It used a fixedbed catalyst to crack petroleum molecules. Particlefluid mass transfer in fixed and fluidized beds. Design, construction, and testing of a fluidized bed reactor tanner iszler mechanical engineering, dr. My thinking was to use the same body for all of the reactors, though with progressively more ports for additional capabilities.
Jerry downey montana tech design and build phase sand was used for the fixed bed and air was used for fluidization. Sodium carbonate and its deep removal in a fixed bed reactor. The reactor can also operate at a continuous state with a fluidized bed. Pla doesnt need an input gas from my understanding. Design and construction of a smallscale fixedbed reactor.
This project presents a specified design of a smallscale fixedbed reactor for the purpose of investigating the gasification processes of biomass and municipal solid wastes. Fluidized bed operations sometimes are alternates to those with fixed. A fluidizedbed reactor was designed and constructed for practical demonstration of the fluidization of solid particles at different fluid flow rates. Fluidised beds are used for several purposes, such as fluidized bed reactors types of chemical reactors, solids separation, fluid catalytic cracking, fluidized bed combustion, heat or mass transfer or interface modification, such as applying a coating onto solid items.
Comparison of the effects of fluidizedbed and fixedbed. Conventional solid fuel power boilers burn the fuel in a fixed bed. By increasing the hydrogen flow rate from 100 mlmin to. Fluidized bed reactor is widely applied in many industries for various applications recently. Optimum mixing in the bed is achieved within specific velocity limits that are function of the particle size of bed material 22. Nov 06, 2016 reaction behaviour in a fluidized bed 22 o to use the kuniilevenspiel model to predict reaction rates in a fluidized bed reactor, the reaction rate law for the heterogeneous reaction per gram or other fixed unit of solid must be known. The heattransfer rate in a fluidized bed can be five to ten times greater than that in a packed bed reactor.
Introduction fluidized bed reactors fixed bed reactors pressure drop calculations catalytic reactor design considerations fluidized and fixed bed reactors chemical reactor analysis and applications for the practicing engineer wiley online library. Bed length for increasing u0 l is constant until onset of fluidization and then begins to increase. Fluidized bed reactor merupakan tempat landasan suatu partikel yang pemasangan gasnya naik melalui suatu titik pencapaian dengan peningkatan laju alir. At high enough velocities fluid drag plus buoyancy overcomes the gravity force and the bed expands. Many industrial plants prefer this method which has high efficiency. They are also used in the oxidation of naphthalene to phtalic anhydride, roasting of sulfide ores, coking of petroleum residues, and the calcination of limestone. In fluidizedbed combustion, a bed of crushed solid particles usually six millimetres or less is made to behave like a fluid by an airstream passing from the bottom of the bed at sufficient velocity to suspend the material in it.
In the years prior to the startup of the first fluidized bed reactor, the world saw the rise of. The early history of fbrs is interwined with world war ii and involved tremendous amounts of engineering skill and capital expense by over 400 oil and chemical processing companies. The apparatus in our lab was designed to allow the study of the characteristics of flow through both fixed and fluidized beds of solid particles. Bottom port for input gas and a gas distributor plate to make it a fluidized bed reactor, side ports to inject additional reactantscatalysts or remove product. Fluidized bed reactor free download as powerpoint presentation. Reactor performance data are compared with mathematical modeling. Fluidized bed characteristics the upward flow of fluid through a bed of solid particles is an important process occurring in nature and in industrial operations. Even for the most extreme exothermic reactions, a fluidized bed can maintain an isothermal profile within a few degrees. In a down draft fixed bed reactor, solid moves slowly down and a vertical. Katalisator diisi lebih dari satu tumpuk katalisator, fixed bed dengan katalisator lebih dari satu tumpuk banyak dipakai dalam proses adiabatik. What is actually happening in fixed bed, fluidised bed. For all fluidizedbed reactor experiments, 1 gram of as prepared catalyst was used at the reactor.
Thus, the benefits of using fluidized bed technology can easily outweigh the disadvantages, especially for processes. In fluidized bed combustion, a bed of crushed solid particles usually six millimetres or less is made to behave like a fluid by an airstream passing from the bottom of the bed at sufficient velocity to suspend the material in it. Moving bed visual encyclopedia of chemical engineering. The heattransfer rate in a fluidized bed can be five to ten times greater than that in a packedbed reactor. Table i represents the variety of studies done on some pollutant degradation on fluidized bed reactor. Consequently, a detailed design of a fluidized bed reactor that would allow flexible operation at high temperature and high pressure at several gas velocities will be conducted in order to serve for the future development of new hydrodynamic models. Because gasification involves the partial, rather than complete, oxidiza. The creation and development of the fluidized bed reactor system for catalytic cracking of petroleum was a cooperative effort that. The animation below shows the operation of a moving bed reactor. Packed bed reactor a fixed or packed bed is an assembly of randomly arranged particles that are bathed by the reactant fluid, which flows in random manner around the pellets. In the years prior to the startup of the first fluidized bed reactor, the world saw the rise of two very strong militaristic countries, germany and japan. The purpose of initial fluidized bed design was coal gasification 79.
Feb 02, 2016 conventional solid fuel power boilers burn the fuel in a fixed bed. These two countries, together and separately, pursued a path that forced most nations of the world to chose sides. Dry desulfurization of simulated flue gas in a fluidizedbed reactor for a broad range of so2 concentration and temperature. Mathematical modeling of catalytic fixed bed reactors. Recently the petrochemical industry uses fluidized bed for catalytic processes such as residue fluidized catalytic cracking rfcc 1. Apr 09, 2018 a fluidized bed is formed when a fixed mass of solid particulate is situated in appropriate conditions to support a solidfluid mixture uniformity to behave as a fluid. Also, depending on the degree of fluidization and bed height, these types of reactors sometimes are also named as circulating fluidized bed reactors, andor transport reactors. The performance of a fluidized bed reactor has been investigated using the ozone decomposition reaction for fresh and spent fluid cracking catalysts, each having three particle size distributions. Fluidized bed is one of the reactors using fluidization 24. Reaction behaviour in a fluidized bed 22 o to use the kuniilevenspiel model to predict reaction rates in a fluidizedbed reactor, the reaction rate law for the heterogeneous reaction per gram or other fixed unit of solid must be known. Data show that for equal normalized residence time and lower fluidbed porosities, the fluidized bed mode leads. Fluidized bed gasifiers may differ in ash conditions dry or agglomeratedslagging and in design configurations for improving char use.
Production of polyethylene using gas fluidized bed reactor tham chee mun ht022626u dept. This results in the medium then having many properties and. Reactants green and catalyst white enter the top of the reactor and move through the vessel. A fluidized bed is formed when a fixed mass of solid particulate is situated in appropriate conditions to support a solidfluid mixture uniformity to behave as a fluid. There are a few disadvantages of using fluidized beds. However, there are often problems faced with the plastic feed such as high viscosities, low thermal conductivities, and irregular shape when being placed inside the. Fluidized bed reactors are commonly used in catalytic cracking processes. Production of polyethylene using gas fluidized bed reactor.
In this type of reactor, a fluid gas or liquid is passed through a solid granular material usually a catalyst possibly shaped as tiny spheres at high enough velocities to suspend the solid and cause it to behave as though it were a fluid. Fluidization occurs when small solid particles are suspended in an upwardflowing stream of fluid, as shown in figure r12. The product of gasification is a combustible synthesis gas, or syngas. A fluidized bed is a wellstirred reactor, characterized by excellent gassolid contact, and uniformity of temperature and composition across the bed. Packedbed situations include such diverse processes as filtration, wastewater treatment, and the flow of crude oil in a petroleum reservoir. During testing, the flow of air was manually adjusted until fluidization of the sand bed. University of groningen particle transport in fluidized. In addition, reactors can be coupled such that the catalyst can be cycled and regenerated. Data show that for equal normalized residence time and lower fluidbed porosities, the fluidized bed mode leads to. However, there are often problems faced with the plastic feed such as high viscosities, low thermal conductivities, and irregular shape when being placed inside the reactor. In this thesis predictions by the recently proposed wave models and the sdm have been compared for several industrial processes in order to indicate the range of applicability of the. Due to the expansion of the materials in the reactor, the size of the vessel must be increased, which leads to a higher initial capital cost. Fundamentals of fluidizedbed chemical processes 1st edition.
The fluidized catalyst particles are shuttled between the fluidized bed reactor and a fluidized bed burner where the coke deposits are burned off, generating heat for the endothermic cracking reaction. Fluidized beds are classified by their flow behavior. Nonadiabatic multitubular fixedbed catalytic reactor model coupled with shellside coolant cfd model. Moving bed reactors are catalytic reactors in which the catalyst moves through the reactor along with the reactants. The fluid bed reactor commemorative booklet produced by the national historic chemical landmarks program of the american chemical society in 1998 pdf. Moving particles, especially small particles, can transport heat much more efficiently than gas alone. Werther j, hartge eu 2004 a population balance model of the particle inventory in a fluidizedbed reactorregenerator system. The animation below shows the operation of a movingbed reactor. Fluidizedbed gasifiers may differ in ash conditions dry or agglomeratedslagging and in design configurations for improving char use. Catalytic fixed bed reactors find wide spread use in chemical industries. Simulation of a fluidized bed reactor for the production of maleic anhydride.
242 566 1485 1033 1343 795 278 1509 299 48 1521 741 1278 1450 833 152 1266 1514 1158 1263 1364 1227 401 1481 810 747 723 1012 100 480 291 1045 430 27 897 1034 1178