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Articles 2431 - 2460 of 2957

Full-Text Articles in Engineering

Low Fouling Crude Oil Preheaters: Scrap Your Existing Conventional Crude Oil Preheaters, Replace Them By Low Fouling Heat Exchangers And Save Money, D.G. Klaren, E.F. De Boer, D.W. Sullivan Jul 2007

Low Fouling Crude Oil Preheaters: Scrap Your Existing Conventional Crude Oil Preheaters, Replace Them By Low Fouling Heat Exchangers And Save Money, D.G. Klaren, E.F. De Boer, D.W. Sullivan

Heat Exchanger Fouling and Cleaning VII

In a time that crude oil prices are constantly higher than US$ 60 per barrel, low fouling heat exchangers can reduce total fouling cost in all crude oil preheat trains in the world with a throughput of 74 Mn bpd by 90%. For 2006, this is a reduction from approximately US$ 11 Bn to US$ 1.3 Bn and a saving on annual fouling cost of US$ 9.7 Bn. Besides this saving on fouling cost, substantial additional savings can be realized on energy by a more ‘energy efficient’ design of the crude oil preheat train. The advantages of the low fouling …

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Intelligent Discrimination Model To Identify Influential Parameters During Crystallisation Fouling, M.R. Malayeri, H. Müller-Steinhagen Jul 2007

Intelligent Discrimination Model To Identify Influential Parameters During Crystallisation Fouling, M.R. Malayeri, H. Müller-Steinhagen

Heat Exchanger Fouling and Cleaning VII

The introduction of redundant independent variables into any function approximation model, or the neglect of important variables, may result in a correlation with poor prediction and reduced reliability. This paper demonstrates that a novel integrated model of neural networks and genetic algorithms can deal with this problem robustly with good accuracy, while be far less time-consuming compared to lengthy conventional models Furthermore, a redundant variable input was imposed to the model to discern if the approach could identify it among other important variables. Genetic algorithms were exploited as a powerful optimisation tool for the selection of best set of inputs …

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Fluid Dynamic Gauging In Duct Flows – Experiments And Cfd Simulations, T. Gu, Y.M.J. Chew, W.R. Paterson, D.I. Wilson Jul 2007

Fluid Dynamic Gauging In Duct Flows – Experiments And Cfd Simulations, T. Gu, Y.M.J. Chew, W.R. Paterson, D.I. Wilson

Heat Exchanger Fouling and Cleaning VII

The technique of fluid dynamic gauging (FDG) has been developed to measure the thickness of deformable foulant deposits on solid immersed in liquid, in real time and in situ, with a precision of ± 10 micron. Suction is imposed across a gauging nozzle; the flow rate of liquid through the nozzle allows calculation of the proximity of the nozzle to the surface of the deposit. The technique has been demonstrated by Tuladhar et al. (2000) to work well in quasi-static situations, where the bulk liquid is not moving apart from the gauging flow, and in duct flows. FDG in the …

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Fouling During The Use Of ‘Fresh’ Water As Coolant- The Development Of A ‘User Guide’, S. J. Pugh, G. F. Hewitt, H. Müller-Steinhagen Jul 2007

Fouling During The Use Of ‘Fresh’ Water As Coolant- The Development Of A ‘User Guide’, S. J. Pugh, G. F. Hewitt, H. Müller-Steinhagen

Heat Exchanger Fouling and Cleaning VII

IHS ESDU recently published its latest ‘User Guide’ to fouling in heat exchange systems, for systems with fresh water as the coolant. ESDU 07006 [1] is the third in a group, following the development of the Crude Oil Fouling User Guide [2] issued in 2000 and the Seawater Fouling User Guide [3] issued in 2004. ESDU 07006 was developed by IHS ESDU over a period of five years under the guidance of the Oil Industry Fouling Working Party, a collaborative team of oil refiners, heat transfer equipment and services suppliers and Universities. It provides designers and operators of cooling water …

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Achievements And Potential Of Self-Cleaning Heat Exchangers Using Untreated Natural Seawater As A Coolant, D.G. Klaren, E.F. De Boer Jul 2007

Achievements And Potential Of Self-Cleaning Heat Exchangers Using Untreated Natural Seawater As A Coolant, D.G. Klaren, E.F. De Boer

Heat Exchanger Fouling and Cleaning VII

The fluidized bed self-cleaning heat exchange technology has been developed in the 70s for the application in thermal desalination plants, like Multi-Stage Flash (MSF) evaporators. This paper summarizes the achievements of the Multi-Stage Flash / Fluidized Bed Evaporator (MSF/FBE) in the past, but also pays attention to its market potential today, whether or not in combination with the possible revamp of existing conventional MSF plants into a better performing configuration. Further, this paper also pays attention to the application of the self-cleaning heat exchange technology for closedloop coolers or so-called ‘mother-coolers’ for large chemical plants. Last but not least, attention …

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Influence Of Different Surface Materials On The Fouling Process In A Microstructured Heat Exchanger Under Laminar Regime, W. Benzinger, J.J. Brandner, U. Schygulla, K. Schubert Jul 2007

Influence Of Different Surface Materials On The Fouling Process In A Microstructured Heat Exchanger Under Laminar Regime, W. Benzinger, J.J. Brandner, U. Schygulla, K. Schubert

Heat Exchanger Fouling and Cleaning VII

Microstructure devices are well known for their excellent performance with regard to heat and mass transfer. Microstructured heat exchangers show significant advantages in comparison with conventional heat exchangers. The unique properties of a microreaction system show high overall heat transfer coefficients for example. Small characteristic dimensions are in the order of a few hundred μm (Schubert et al., 1998, 2001; Worz et al, 1998). Due to the small dimensions, an increased pressure drop is combined with excellent heat transfer properties. But the small channels are prone to fouling processes. The accumulation of crystalline deposits is a severe problem. An additional …

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Cleaning And Prevention Of Inorganic Deposits In Plate Heat Exchangers Using Pulsating Current, A. Pehkonen, J. Aromaa, O. Forsén, J. Virtanen, I. Galfi Jul 2007

Cleaning And Prevention Of Inorganic Deposits In Plate Heat Exchangers Using Pulsating Current, A. Pehkonen, J. Aromaa, O. Forsén, J. Virtanen, I. Galfi

Heat Exchanger Fouling and Cleaning VII

Fouling of heat exchangers is a major problem in many industrial processes. The higher temperature of the heat exchange surface compared with the liquid containing precipitable compounds causes the formation of inorganic deposits. Removing the deposits on plate heat exchangers is most often carried out by high-pressure cleaning. This is a laborious task and often increases the corrosion rate of the plates by increasing the roughness of the cleaned surface. This study presents an electrochemical method to clean heat exchange surfaces fouled by deposits and to prevent formation of deposits. This method utilizes pulsating current to polarize heat exchange surfaces …

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Hitran® Wire Matrix Inserts In Fouling Applications, J.M. Ritchie, P. Droegemueller, M.J.H. Simmons Jul 2007

Hitran® Wire Matrix Inserts In Fouling Applications, J.M. Ritchie, P. Droegemueller, M.J.H. Simmons

Heat Exchanger Fouling and Cleaning VII

Fouling characteristics are dictated largely by the properties of the thermal and hydrodynamic boundary layers. As a result, fouling mitigation strategies must take into account the conditions in this region. hiTRAN® wire matrix tube inserts are a useful tool in altering the conditions near the tube wall, especially in the laminar and transition flow regions. This review paper considers Particle Image Velocimetry (PIV) and Laser Doppler Velocimetry (LDV) measurements, which were employed in order to show the hydrodynamic differences between plain tubes and those containing inserts. Measurements indicate that the wall shear rate in tubes containing hiTRAN® inserts operating in …

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Automatic Tube Cleaning System (Atcs) Installation In Sulfide Retrieval Monoethanolamine Treatment Plant: Case Study And Fouling Global Perspectives, Chemi Sugarmen, Udi Siboni, Ruth Volansky Jul 2007

Automatic Tube Cleaning System (Atcs) Installation In Sulfide Retrieval Monoethanolamine Treatment Plant: Case Study And Fouling Global Perspectives, Chemi Sugarmen, Udi Siboni, Ruth Volansky

Heat Exchanger Fouling and Cleaning VII

Automatic cleaning of heat exchangers and condensers tubes by means of sponge balls is well known since the early fifties, with expanding application from steam power plants to process industry to industrial cooling and air conditioning systems. Main benefits bottom-lined in cost savings are generally considered as: elimination of maintenance down-time and need for chemical and more efficient operation of process and plant. This paper presents the performance and benefits of an Automatic Tube Cleaning System (ATCS) implementations, in a hydrogen sulfide retrieval Monoethanolamine treatment Plant in Paz Ashdod Refinery, one of the two refineries in Israel. Patented by CQM …

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Double Perforated Impingement Plate (Dpip) In Shell-And-Tube Heat Exchanger, S. S. Al-Anizi, A. M. Al-Otaibi Jul 2007

Double Perforated Impingement Plate (Dpip) In Shell-And-Tube Heat Exchanger, S. S. Al-Anizi, A. M. Al-Otaibi

Heat Exchanger Fouling and Cleaning VII

This paper presents a solution to a chronic problem causing repeated tube failure at shell-and-tube heat exchangers. The problem is related to fouling process on tubes surface which accumulates downstream the impingement plate at exchanger inlet nozzle within the first tube rows due to low velocity and vortices production. In fouling services, the suspended deposits, fouling, accumulates on tubes surface downstream the impingement plate causing under-deposit corrosion and raising tubes surface temperature due to lack of cooling accelerating fouling process. Under fouling corrosion attacks tubes and causes repeated tube failure costing a lot of money in terms of material, maintenance …

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Towards An Understanding Of How Tube Inserts Mitigate Fouling In Heat Exchangers, B. Aquino, C. Derouin, G.T. Polley Jul 2007

Towards An Understanding Of How Tube Inserts Mitigate Fouling In Heat Exchangers, B. Aquino, C. Derouin, G.T. Polley

Heat Exchanger Fouling and Cleaning VII

A number of studies undertaken by Total have measured the improvement that can be expected when TurbotalTM inserts are installed in heat exchangers. These studies have fully established that TurbotalTM both improve heat transfer coefficient and mitigate fouling. It has been found that fouling levels vary with application. Consequently, economics of installing inserts are difficult to quantify. Gains must be estimated through specific tests. A model that predicts fouling development solves this problem. In this paper first steps towards the understanding of how TurbotalTM limits the fouling rate are described. Authors suggest that the calculation of both pressure drop and …

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Cleaning High-Speed Marine Separators With An Environmentally-Friendly Cip Agent, Ulf Nylén, Roger Andersson, Peter Forsberg Jul 2007

Cleaning High-Speed Marine Separators With An Environmentally-Friendly Cip Agent, Ulf Nylén, Roger Andersson, Peter Forsberg

Heat Exchanger Fouling and Cleaning VII

The present contribution is devoted to the cleaning of high-speed marine separators employing the environmentally-friendly Cleaning In Place (CIP) agent Alpacon Multi Cip Super. For this particular study an Alfa Laval lube oil separator of type S831 on board the ship MS Isabella was dismantled prior to its first CIP treatment since installation and a few of the sludge-coated insert discs were taken as samples for laboratory experiments. Following assembly, the separator was cleaned according to a standard CIP protocol. Back in the laboratory, experiments mimicking the field CIP conditions verified the excellent cleaning results observed by visual inspection out …

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Biofouling Control In Heat Exchangers Using High Voltage Capacitance Based Technology, R. Romo, M. M. Pitts, N. B. Handagama Jul 2007

Biofouling Control In Heat Exchangers Using High Voltage Capacitance Based Technology, R. Romo, M. M. Pitts, N. B. Handagama

Heat Exchanger Fouling and Cleaning VII

Biofouling in industrial heat exchangers and piping systems is common in water from all sources. Problems generated by biofouling such as corrosion, sludge deposition and scale formation have a costly impact on industrial equipment and productivity. This paper describes an electronic approach using High Voltage Capacitance Based technology (HVCB) to control biofouling in industrial heat exchangers, focusing upon biofilm removal and the prevention of biofilm formation. Four different application case studies are presented in this paper in which the HVCB technology was used to control biofouling. The applications include an evaporative cooling wall in a greenhouse in Oracle, Arizona; a …

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Cleaning Monitoring Using Controlled Nano-Vibrations, A. Pereira, J. Mendes, L.F. Melo Jul 2007

Cleaning Monitoring Using Controlled Nano-Vibrations, A. Pereira, J. Mendes, L.F. Melo

Heat Exchanger Fouling and Cleaning VII

The monitoring of fouling and cleaning has become very important in order to optimize production cycles, to increase the quality of the final product and to reduce environmental impacts. The aim of the study here presented was to use the MSS – Mechatronic Surface Sensor, to detect the cleaning end-point of hair shampoo removal under different cleaning conditions. It was found that this new monitoring tool was able to clearly identify when the equipment was cleaned, producing different cleaning curves for different cleaning conditions.

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Solving A Hydtrotreater Feed Filter Fouling Problem, X.A. Wu, K.H. Chung Jul 2007

Solving A Hydtrotreater Feed Filter Fouling Problem, X.A. Wu, K.H. Chung

Heat Exchanger Fouling and Cleaning VII

Feed filters were installed in Syncrude hydrotreater units to protect the catalyst beds from plugging by fine solids in the feed. Severe filter fouling occurred after a process flow sheet change. The root cause of fouling was revealed through a step-by-step scientific investigation. It was first confirmed that the fouling problem was related to a process flow sheet change that introduced a heavy vacuum gas oil (HVGO) stream into the coker combined gas oil (KCGO) stream prior to filtration. Characterization of the foulant and the feed indicated that the fouling reactions are likely oxidative polymerization. Iron naphthenate or naphthenic acid …

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Electrochemical Impedance And Digital Image Methods To Detect Initial Deposition Of Microorganisms, H. Men, S. W. Mu, Z. W. Lu, Y. L. Chen, S.R. Yang, Y. P. Jia, S. X. Cao Jul 2007

Electrochemical Impedance And Digital Image Methods To Detect Initial Deposition Of Microorganisms, H. Men, S. W. Mu, Z. W. Lu, Y. L. Chen, S.R. Yang, Y. P. Jia, S. X. Cao

Heat Exchanger Fouling and Cleaning VII

Microorganism in industrial cooling water can cause corrosion and biofouling. Electrochemical impedance method and digital image method (DIM) were used to detect quantitatively iron bacteria and heterotrophic bacteria. Microorganism growth and metabolism can change the impedance of culture medium. The detection time of impedance variation lie in the function relationship with the logarithm of bacteria concentration. 7-million-pixel CCD sensor was used to shoot the shape of microorganism in order to count the number. Compared with most probable number (MPN) method, the detection time of electrochemical impedance is shortened. The DIM reduces the bacteria counting time and the inaccuracy associated with …

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Slag Monitoring System For Combustion Chambers Of Steam Boilers, J. Taler, D. Taler Jul 2007

Slag Monitoring System For Combustion Chambers Of Steam Boilers, J. Taler, D. Taler

Heat Exchanger Fouling and Cleaning VII

The computer based boiler performance system, presented in this paper, has been developed to provide a direct and quantitative assessment of furnace and convective surface cleanliness. Temperature, pressure and flow measurements and gas analysis data are used to perform heat transfer analysis in the boiler furnace and evaporator. Power boiler efficiency is calculated using an indirect method. The on-line calculation of the exit flue gas temperature in a combustion chamber allows for an on-line heat flow rate determination, which is transferred to the boiler evaporator. Based on the energy balance for the boiler evaporator, the superheated steam mass flow rate …

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Cover Page, Hans Müller-Steinhagen, M. Reza Malayeri, Paul Watkinson Jul 2007

Cover Page, Hans Müller-Steinhagen, M. Reza Malayeri, Paul Watkinson

Heat Exchanger Fouling and Cleaning VII

No abstract provided.

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Free Alkali-Index For Optimizing The Fuel Mixture In Biomass Co-Firing, T.E. Blomberg Jul 2007

Free Alkali-Index For Optimizing The Fuel Mixture In Biomass Co-Firing, T.E. Blomberg

Heat Exchanger Fouling and Cleaning VII

Co-firing biomass with fossil fuels provides a cheap and efficient reduction of the CO2 emissions in electricity generation. One of the main challenges in co-firing is the increased fouling and corrosion rates of the heat transfer surfaces when biomass is added to the fuel mixture. Optimization of the fuel mixture from the fouling and corrosion point of view would be an easier task, if some fuel properties would provide correlation with the fouling and corrosion rates. Currently there is no clear understanding of the most useful fuel indices. The fouling indices used in coal firing have proved to be less …

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The Science Of Cleaning Of Dairy Fouling Layers, R. Mercadé-Prieto,, W.R. Paterson, D.I. Wilson Jul 2007

The Science Of Cleaning Of Dairy Fouling Layers, R. Mercadé-Prieto,, W.R. Paterson, D.I. Wilson

Heat Exchanger Fouling and Cleaning VII

The science underlying the removal of dairy fouling layers, and particularly the dissolution of proteinaceous deposits in alkaline solution, is relatively poorly understood even though this is a critical feature of many cleaning-in-place operations. We report key results from a series of investigations on heat-induced gels of β- lactoglobulin, the primary whey protein component in milk and whey foulant. These model systems were used to elucidate the reaction behaviour of gels and aggregates whereby the proteinaceous material is converted to a softer, swollen form that can then be removed by fluid shear or diffusion. We show that several features, such …

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Study Of An Organic Crystallization Fouling Problem, Hirofumi Inokuchi, Mitsutaka Nakamura, Yoshio Koga Jul 2007

Study Of An Organic Crystallization Fouling Problem, Hirofumi Inokuchi, Mitsutaka Nakamura, Yoshio Koga

Heat Exchanger Fouling and Cleaning VII

One of the aromatic compound plants in Mitsubishi Chemical Corporation has a heavy crystallization fouling problem. We have been studying the crystallization process using the shell and tube heat-exchanger. In order to solve our fouling problem of the heat exchanger, we developed the specified evaluation equipment (crystallization fouling simulator : CFS) which consists of a single tube heatexchanger (Tube size: ID=10.3mm Length=500mm). The result of the modeling for describing the crystallization fouling rate and the countermeasure of the fouling problem are discussed in this work. It can be possible to describe the fouling rate as one equation which has two …

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Bacterial And Protein Adhesion On Ni-P-Ptfe Coated Surfaces, Q. Zhao, C. Liu, Y. Liu, S. Wang Jul 2007

Bacterial And Protein Adhesion On Ni-P-Ptfe Coated Surfaces, Q. Zhao, C. Liu, Y. Liu, S. Wang

Heat Exchanger Fouling and Cleaning VII

The adhesion of bacteria and proteins on the surfaces of heat exchangers and food processing equipment has been recognized as a widespread problem. Biofouling not only reduces heat transfer performance significantly, but also causes considerable pressure drop, calling for higher pumping requirements. Biofouling also present a considerable hygiene risk in the food industry. It would be much more desirable if surfaces with an inherently lower stickability for biofouling could be developed. In this paper, stainless steel 304 plates were modified by electroless plating Ni-P and small amounts of PTFE. The experimental results showed that the surface free energy of the …

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Evaluation Of Heat Transfer Boundary Conditions For Cfd Modeling Of A 3d Plate Heat Exchanger Geometry, T.M. Pääkkönen, M. Riihimäki, R. Ylönen, E. Muurinen, C.J. Simonson, R.L. Keiski Jul 2007

Evaluation Of Heat Transfer Boundary Conditions For Cfd Modeling Of A 3d Plate Heat Exchanger Geometry, T.M. Pääkkönen, M. Riihimäki, R. Ylönen, E. Muurinen, C.J. Simonson, R.L. Keiski

Heat Exchanger Fouling and Cleaning VII

In this paper fluid flow and heat transfer are modeled in a corrugated 3D plate heat exchanger geometry with a commercial computational fluid dynamics (CFD) program, Fluent 6.1.22 (Fluent Inc., Lebanon), in order to find out the most realistic heat transfer boundary conditions for a plate heat exchanger. The built-in boundary conditions of Fluent available for this case are Heat flux, Convection and Constant wall temperature. The CFD models are verified with correlations and experimental data obtained by a flat plate test equipment of which parameters can be calculated analytically. Deficiencies are found in all the built-in heat transfer boundary …

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Metallic Micro Heat Exchangers: Properties, Applications And Long Term Stability, J.J. Brandner, W. Benzinger, U. Schygulla, S. Zimmermann, K. Schubert Jul 2007

Metallic Micro Heat Exchangers: Properties, Applications And Long Term Stability, J.J. Brandner, W. Benzinger, U. Schygulla, S. Zimmermann, K. Schubert

Heat Exchanger Fouling and Cleaning VII

Micro heat exchangers, which until recently have been implemented only at laboratory scale, are now being available for industrial applications. They are well known for their superior heat transfer properties due to the large surface-to-volume ratio. But there are little data available on the long term stability of these devices. In this paper application several application examples for micro heat exchangers made of stainless steel are presented. The devices consist of stainless steel foils providing numerous micro channels generated by mechanical micromachining or wet chemical etching. A number of the foils are arranged in a specific way and bonded together. …

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Fouling Monitoring And Cleaning Optimisation In A Heat Exchanger Network Of A Crude Distillation Unit, Andrea Heins, Ramón Veiga, Carlos Ruiz, Andrés Riera Jul 2007

Fouling Monitoring And Cleaning Optimisation In A Heat Exchanger Network Of A Crude Distillation Unit, Andrea Heins, Ramón Veiga, Carlos Ruiz, Andrés Riera

Heat Exchanger Fouling and Cleaning VII

Fouling in preheat networks of crude distillation units (CDU) plays an important role in energy consumption. In this work a procedure to monitor the performance of the heat exchanger network (HEN) and to optimize the cleaning strategies is presented. The procedure is based on a rigorous simulation of the HEN using Hysys (from Aspen Technology). The simulation is used to estimate the service overall heat transfer coefficient with real operational data acquired from the unit’s Plant Information System (PI). The clean overall heat transfer coefficient is calculated for each one of the individual heat exchangers with a rigorous simulation using …

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Cfd And Neural Network-Based Expert System For The Supervision Of Boilers And Furnaces, Hugo Calisto, Nelson Martins, Naim Afgan Jul 2007

Cfd And Neural Network-Based Expert System For The Supervision Of Boilers And Furnaces, Hugo Calisto, Nelson Martins, Naim Afgan

Heat Exchanger Fouling and Cleaning VII

CFD (Computational Fluid Dynamics) tools were used to build a "virtual" furnace, validated with experimental data. This model was used to simulate both normal and “faulty” behaviours, regarding parameters such as energy conversion efficiency, steam leakage and fouling. A database was developed comprising normal situations and simulated fault sets, characterized by virtual sensor outputs used in the evaluation of diagnostic parameters patterns to be processed and recognized by the diagnostic system. The database was processed using Neural Networks, with satisfactory results even in their most simple form (backpropagation networks) trained using standard algorithms. Pattern recognition was thus performed, identifying root …

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A Computational Study Of The Distribution Of Particles In A Lab-Scale Cfb Boiler, Kim G. Hansen, Tron Solberg, Bjorn H. Hjertager May 2007

A Computational Study Of The Distribution Of Particles In A Lab-Scale Cfb Boiler, Kim G. Hansen, Tron Solberg, Bjorn H. Hjertager

The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering

When two-fluid modeling is used to predict riser flows there have been difficulties in predicting the solids hold up in risers represented by the correct pressure drop profile. A way of encountering this inherent problem in current Eulerian-Eulerian CFD modeling is to approximate the actual particle size distribution by using more particle phases instead of the current practice of using one mean diameter. For the lab-scale CFB investigated, CFD simulations show that a mal-distribution occurs in the CFB; the larger particles are retained in the riser, whereas the intermediate and small particles are distributed both in the return leg and …

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Flow Structures In The Bottom Region Of Riser, Haiyan Zhu, Jesse Zhu May 2007

Flow Structures In The Bottom Region Of Riser, Haiyan Zhu, Jesse Zhu

The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering

This paper studied hydrodynamic characteristics in bottom region of CFB risers with FCC particles over a wide range of operating conditions. Results included solids concentration, particle velocity, and probability density distributions. Comparisons were made between flow structures in riser bottom region and that in bubbling and turbulent fluidized bed.

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Hydrodynamic Characteristics Of A Fluidized Bed With Rotating Distributor, C. Sobrino, S. Sánchez-Delgado, J. A. Almendros-Ibáñez, M. De Vega, U. Ruiz-Rivas, D. Santana May 2007

Hydrodynamic Characteristics Of A Fluidized Bed With Rotating Distributor, C. Sobrino, S. Sánchez-Delgado, J. A. Almendros-Ibáñez, M. De Vega, U. Ruiz-Rivas, D. Santana

The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering

The performance of a novel rotating distributor fluidized bed is presented. The pressure drop and the standard deviation of pressure fluctuations, σp, were used to find the minimum fluidization velocity, Umf, and to characterize the quality of fluidization at different rotational speeds of the distributor plate. Experiments were conducted in the freely bubbling regime in a 0.19 m i.d. fluidized bed, operating with Group B particles according to Geldart’s classification. A decrease in Umf is observed when the rotational speed increases. Frequency analysis of pressure fluctuations shows that fluidization can be controlled by the adjustable rotational speed, at several excess …

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Friction Between Gas-Solid Suspension And Circulating Fluidized Bed Downers, Xiaobo Qi, Hui Zhang, Jesse Zhu May 2007

Friction Between Gas-Solid Suspension And Circulating Fluidized Bed Downers, Xiaobo Qi, Hui Zhang, Jesse Zhu

The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering

Friction between co-current downflow gas-solid suspension and the column wall was investigated. A new model to predict pressure drops due to friction between the gas-solid suspension in the fully developed section and the downer wall was developed. The results show that the friction between the gas-solids suspension and the downer wall causes a significant deviation of the apparent solids concentrations from the actual ones, especially for those operating conditions with higher superficial gas velocities and solids circulation rates. When the superficial gas velocity is greater than 8 m/s, the actual solids concentrations in the fully developed region of the downer …

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