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Table Of Contents, Hans Müller-Steinhagen, M. Reza Malayeri, Paul Watkinson
Table Of Contents, Hans Müller-Steinhagen, M. Reza Malayeri, Paul Watkinson
Heat Exchanger Fouling and Cleaning VII
No abstract provided.
Free Alkali-Index For Optimizing The Fuel Mixture In Biomass Co-Firing, T.E. Blomberg
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 …
Crystallization Fouling Behaviour Of Uranium Oxide And Alumnosilicate Scale In High Level Nuclear Waste Medium, Jonas Addai-Mensah, Jun Li, Bill Wilmarth
Crystallization Fouling Behaviour Of Uranium Oxide And Alumnosilicate Scale In High Level Nuclear Waste Medium, Jonas Addai-Mensah, Jun Li, Bill Wilmarth
Heat Exchanger Fouling and Cleaning VII
During high level nuclear waste (HLNW) liquor processing in evaporators operating in the temperature range 30 - 140 °C, dissolved silica, alumina, sodium hydroxide, uranium-235 and transuranic species (e.g. plutonium-238) invariably become concentrated. As the liquor evaporation proceeds, the sodium aluminosilicate (SAS) and radionuclides may exceed their solubility limits and co-precipitate, fouling the tubes and walls of the evaporator. If the fouling process is not effectively controlled or mitigated, radionuclide scale accumulation exceeding the critical mass necessary for self-sustaining nuclear fission reaction may proceed at an alarming rate, posing a serious criticality concern. To probe the mechanisms underpinning uranium oxide-sodium …
Precipitation And Fouling In Heavy Oil–Diluent Blends, E Hong, A. Paul Watkinson
Precipitation And Fouling In Heavy Oil–Diluent Blends, E Hong, A. Paul Watkinson
Heat Exchanger Fouling and Cleaning VII
Heavy oil fractions rich in asphaltenes were mixed with diluents containing from 0.6-25% aromatics, and the resulting blends subjected to batch precipitation experiments at 85°C, and thermal fouling tests at surface temperatures in the range 230-310ºC. Deposit compositions were determined, and are compared with suspended asphaltene composition. When the heavy oils were blended with the most aromatic diluents, precipitation and fouling were negligible. As the aromaticity of the diluents was decreased, the extent of asphaltene precipitation and the fouling rates increased. The solubility parameter of the blends, δmix, and the flocculation solubility parameter for asphaltenes, δf , were determined from …
Costs Due To Utility Fouling In China, Xu Zhi-Ming, Zhang Zhong-Bin, Yang Shan-Rang
Costs Due To Utility Fouling In China, Xu Zhi-Ming, Zhang Zhong-Bin, Yang Shan-Rang
Heat Exchanger Fouling and Cleaning VII
This paper puts forward a method for evaluating the fouling costs of boilers and turbines in power plants. Furthermore, the Huaneng Dalian Power Plant and Changshan Power Plant are taken as examples for analyzing the costs of fouling. Based on data of on-site measurements in the above Power Plants, the costs due to fouling such as excess surface area, product loss, operating maintenance and increase of product costs are calculated. Results show that the total economical loss due to boiler and turbine fouling in China reaches 4.68 billion dollars, which covers is about 0.169% GDP of China in 2006.
Crude Oil Fouling In A Pilot-Scale Parallel Tube Apparatus, B. D. Crittenden, S. T. Kolaczkowski, T. Takemoto, D. Z. Phillips
Crude Oil Fouling In A Pilot-Scale Parallel Tube Apparatus, B. D. Crittenden, S. T. Kolaczkowski, T. Takemoto, D. Z. Phillips
Heat Exchanger Fouling and Cleaning VII
Maya crude oil fouling reveals a seemingly straightforward dependency of initial fouling rate on surface temperature but a maximum is found in the initial fouling rate – velocity relationship which mirrors that found in a model chemical system of styrene polymerization. The linear dependency of the logarithm of the pre-exponential factor on apparent activation energy for the crude oil is also found in the styrene system. The apparent activation energy for the crude oil ranged from 26.4 kJ/mol at 1.0 m/s to 245 kJ/mol at 4.0 m/s. Such strong dependencies of apparent activation energy on velocity, even at high velocity, …
Scale Deposits In Porous Media And Their Removal By Edta Injection, J. Moghadasi, H. Müller-Steinhagen, M. Jamialahmadi, A. Sharif
Scale Deposits In Porous Media And Their Removal By Edta Injection, J. Moghadasi, H. Müller-Steinhagen, M. Jamialahmadi, A. Sharif
Heat Exchanger Fouling and Cleaning VII
Formation damage has been observed in several oil reservoirs and production equipment in Iranian oil fields. Laboratory and field testing confirmed that the primary cause of damage was the build-up of calcium carbonate, calcium sulfate and strontium sulfate scale either in the perforation tunnels or in the formation sandstone nears the wellbore. Conventional acid treatments could dissolve this scale, but scale precipitation from the spent acid caused rapid productivity decline. A scale removal treatment with Na2H2EDTA has been developed that can effectively dissolve scale and chelate the dissolved metal ions. Chelation of the dissolved scale prevents scale reprecipitation. This study …
The Effect Of Fouling On Heat Transfer, Pressure Drop And Throughput In Refinery Preheat Trains: Optimisation Of Cleaning Schedules, E. M. Ishiyama, W. R. Paterson, D. I. Wilson
The Effect Of Fouling On Heat Transfer, Pressure Drop And Throughput In Refinery Preheat Trains: Optimisation Of Cleaning Schedules, E. M. Ishiyama, W. R. Paterson, D. I. Wilson
Heat Exchanger Fouling and Cleaning VII
Optimising cleaning schedules for refinery preheat trains requires a robust and reliable simulator, reliable fouling models and the ability to handle the thermal and hydraulic impacts of fouling. The interaction between thermal and hydraulic effects is explored using engineering analyses and fouling rate laws based on the ‘threshold fouling’ concept; the potential occurrence of a new phenomenon, ‘thermo-hydraulic channeling’ in parallel heat exchangers, is identified. The importance of the foulant thermal conductivity is highlighted. We also report the development of a highly flexible preheat train simulator constructed in MATLAB&#;/Excel&#;. It is able to accommodate variable throughput, control valve operation and …
Formation Of Gum And Deposits In An Oxygenated Naphtha Stream, Yonghua Li, Paul Watkinson, Patricio Herrera, Feridoun Fahiminia, Morgan James
Formation Of Gum And Deposits In An Oxygenated Naphtha Stream, Yonghua Li, Paul Watkinson, Patricio Herrera, Feridoun Fahiminia, Morgan James
Heat Exchanger Fouling and Cleaning VII
Gums formed when organic fluids are in contact with air can cause fouling of process equipment. The oxidation and formation of gum in a naphtha stream was studied in a stirred batch reactor as a function of temperature (96 to 130ºC) and at a total pressure of 584 kPa. Mixtures of air and nitrogen in the pressurizing gas gave dissolved oxygen contents in the range 10-270 ppm wt. Peroxide and existent (dissolved) gum contents were measured over periods of up to 80 hours. Rates of reaction were low, with maximum concentrations of peroxide typically below 4 meq/L, and gum formation …
Observation Of An Isokinetic Temperature And Compensation Effect For High Temperature Crude Oil Fouling, C. A. Bennett, R. S. Kistler, K. Nangia, W. Al-Ghawas, N. Al-Hajji, A. Al-Jemaz
Observation Of An Isokinetic Temperature And Compensation Effect For High Temperature Crude Oil Fouling, C. A. Bennett, R. S. Kistler, K. Nangia, W. Al-Ghawas, N. Al-Hajji, A. Al-Jemaz
Heat Exchanger Fouling and Cleaning VII
The initial fouling rates of four crude oils were determined at a nominal bulk temperature of 315 °C, an initial heated wall shear stress of 13 Pa, and initial surface temperatures between 375 and 445 °C. These initial fouling rates ranged from 1.3(10-6) to 7.8(10-5) m2 K/kJ. Corresponding Arrhenius plots were linear with the initial fouling rates passing through an isokinetic temperature of 407.5 °C. A plot of the natural logarithm of the preexponential factors (7.6(104) – 5.2(1015) m2 K/kJ) versus the apparent activation energies (128 – 269 kJ/mol) was also linear, confirming the validity of the isokinetic temperature and …
Investigation Of The Mechanisms Of Heat Exchanger Corrosion In A Municipal Waste Incineration Plant By Analysis Of The Raw Gas And Variation Of Operating Parameters, C. Deuerling, J. Maguhn, H. Nordsieck, B. Benker, R. Zimmermann, R. Warnecke
Investigation Of The Mechanisms Of Heat Exchanger Corrosion In A Municipal Waste Incineration Plant By Analysis Of The Raw Gas And Variation Of Operating Parameters, C. Deuerling, J. Maguhn, H. Nordsieck, B. Benker, R. Zimmermann, R. Warnecke
Heat Exchanger Fouling and Cleaning VII
The detailed mechanism of high temperature chlorine corrosion, the dominant cause of corrosion in a municipal solid waste incinerator (MSI), has still to be clarified (Schroer, 2002). Upon its way through the boiler the raw gas is subject to various physical and chemical processes and interactions. Of these, sulphation of chlorides is supposed to have the major impact on chlorine corrosion (Neumann, 1997). The physical and chemical mechanisms of corrosion were investigated at a municipal solid waste incinerator. Both, the particulate and gas phase of the flue gas, were chemically and physically analyzed during their way through the boiler, at …
Milk Protein Fouling In A Tubular Heat Exchanger: Effect Of Milk Temperature And Reynolds Number, D.H.G. Pelegrine, K.F. Oliveira, M.T.M.S. Gomes
Milk Protein Fouling In A Tubular Heat Exchanger: Effect Of Milk Temperature And Reynolds Number, D.H.G. Pelegrine, K.F. Oliveira, M.T.M.S. Gomes
Heat Exchanger Fouling and Cleaning VII
In the present work, β-lactoglobulin fouling phenomenon was studied, when milk flowed in a tubular heat exchanger, where hot water was used to raise milk temperature. Experiments have been carried out to determine the effect of Reynolds number and fluid temperature in whey protein fouling, in a tubular heat exchanger and the results showed that fouling increases as the fluid temperature increases. In addition, as the Reynolds number increases, the total amount of fouling (obtained by integrating the whole amount of deposit down the tube dividing by the total area) decreased.
The Thermo-Hydrodynamics Of A Concentric Ohmic Heater For Processing Dairy Fluids, H.J. Tham, X.D. Chen, B. Young, B. Bansal, L. Zhang, G. Duffy
The Thermo-Hydrodynamics Of A Concentric Ohmic Heater For Processing Dairy Fluids, H.J. Tham, X.D. Chen, B. Young, B. Bansal, L. Zhang, G. Duffy
Heat Exchanger Fouling and Cleaning VII
The thermo-hydraulic performance of a 300W concentric annular ohmic heater was investigated. To minimize possible electrochemical reactions and corrosion, a higher frequency was applied and factors of field strength and frequency were studied. 2D computer simulation solving momentum, thermal and electrical energy was performed using the FlexPDE software. A good agreement between experimental and analytical analysis of static heating was obtained. There were significant differences between calculated and measured wall temperature near the entrance. The calculated outlet temperature was however in reasonable agreement with the experiment value.
Influence Of Different Surface Materials On Nucleation And Crystal Growth In Heat Exchangers, T. Geddert, S. Kipp, W. Augustin, S. Scholl
Influence Of Different Surface Materials On Nucleation And Crystal Growth In Heat Exchangers, T. Geddert, S. Kipp, W. Augustin, S. Scholl
Heat Exchanger Fouling and Cleaning VII
The influence of different materials on the fouling tendency in saline calcium sulfate solution was investigated. The effects of the untreated material on the crystallization process have been studied experimentally in the micro- and macroscopic scale. The crystallization in the induction period was visualized with SEM and AFM to locate preferred nucleation spots and to visualize the crystal growth. The different materials are showing different crystal growth behavior (number and size of the crystals). These results are corresponding with the macroscopic fouling results with limited shear stress. Also different roughness values on stainless steel have been studied with respect to …
Fouling In A Centritherm Evaporator With Whey Solutions, R. S. Jebson, H. Chen, O. H. Campanella
Fouling In A Centritherm Evaporator With Whey Solutions, R. S. Jebson, H. Chen, O. H. Campanella
Heat Exchanger Fouling and Cleaning VII
Fouling caused by sweet cheese whey and reconstituted whey powder solutions was studied in a Centritherm evaporator, the behaviour being estimated by measuring the change in the overall heat transfer coefficients with the time. It was found that there was no fouling detectable for the reconstituted whey powder solution. For sweet cheese whey, the fouling rate was linked strongly with the evaporating temperature and temperature difference. Visual observation showed that the deposit layer on the evaporator surface was very thin and soft, and like the type A milk deposit described by other investigators. A high velocity of liquid film delayed …
Simulation Of Calcium Phosphate Deposition On Stainless Steel Surfaces: A New Approach Based On Cellular Automata, F. G. Martins, T. Campos, R. Rosmaninho, L. F. Melo
Simulation Of Calcium Phosphate Deposition On Stainless Steel Surfaces: A New Approach Based On Cellular Automata, F. G. Martins, T. Campos, R. Rosmaninho, L. F. Melo
Heat Exchanger Fouling and Cleaning VII
Fouling caused by calcium phosphate upon heating is basically a crystallization/precipitation process, which starts with the formation of stable clusters of ions or molecules in a process called nucleation that occurs either in the bulk liquid or at the surface. The cellular automata are useful tools to model complex systems of the universe. They could be considered as a good alternative to differential equations and have been used to model many physical/biological systems. In this preliminary work, a two dimensional space was considered where the cellular automata lattice was represented as a grid of squares, with each square representing a …
A Real Time Monitoring Model Of The Calcium Carbonate Fouling Induction Period Based On The Conductance Titration, S.R. Yang, S.X. Cao, L.J. Chen, Z.M. Xu, M.L. Yu, W.H. Sun, K.L. Zheng
A Real Time Monitoring Model Of The Calcium Carbonate Fouling Induction Period Based On The Conductance Titration, S.R. Yang, S.X. Cao, L.J. Chen, Z.M. Xu, M.L. Yu, W.H. Sun, K.L. Zheng
Heat Exchanger Fouling and Cleaning VII
A new method has been developed to monitor the calcium carbonate fouling induction period (CCFIP) in real time. Based on the conductance titration, this paper investigated the forming process of CCFIP by a staticdynamic combined simulation experiment unit. With the help of titration analysis (that is titrimetry), an accurate definition of CCFIP and the corresponding real time monitoring model were built up. The investigation results show that the proposed model applies not only to measure the CCFIP in real time, but also applies to an investigation of the influence of various factors on the CCFIP.
The Science Of Cleaning Of Dairy Fouling Layers, R. Mercadé-Prieto,, W.R. Paterson, D.I. Wilson
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 …
Surface Treatment For The Mitigation Of Whey Protein Fouling, W. Augustin, T. Geddert, S. Scholl
Surface Treatment For The Mitigation Of Whey Protein Fouling, W. Augustin, T. Geddert, S. Scholl
Heat Exchanger Fouling and Cleaning VII
Heat transfer fouling experiments were carried out in a temperature controlled stirred vessel using aqueous solutions of whey protein concentrate in the concentration range of 3 to 3.5 wt-% at a bulk temperature of 50 °C and pH of 6. Heat transfer data were obtained from thermocouples embedded in an immersed electrical heating rod with various metal plates attached with-and-without surface treatments. Measurements included solution temperature, heating element surface temperature, and heat duty. Results are presented as fouling resistance versus time for aluminum, copper, stainless steel, electro-polished stainless steel, and surfaces coated with DLC and doped with Si , SiO, …
Experiments And Modelling Of Calcium Sulphate Precipitation Under Sensible Heating Conditions: Initial Fouling And Bulk Precipitation Rate Studies, F. Fahiminia, A. P. Watkinson, N. Epstein
Experiments And Modelling Of Calcium Sulphate Precipitation Under Sensible Heating Conditions: Initial Fouling And Bulk Precipitation Rate Studies, F. Fahiminia, A. P. Watkinson, N. Epstein
Heat Exchanger Fouling and Cleaning VII
Crystallization of calcium sulphate, an inverse solubility salt, on a heated surface under sensible heating conditions has been studied. A temperature measurement technique was employed to detect initial fouling rates. Fouling experiments were carried out to determine how process variables such as surface temperature and velocity affect the initial fouling rates of calcium sulphate scaling. Experimental results show that, at a given surface temperature, there exists a maximum initial fouling rate for a range of fluid velocities. Also, this maximum rate and the fluid velocity at which it occurs both increase as the surface temperature increases. These observations are all …
Flow Cell Studies On Fouling Caused By Protein -Calcium Phosphate Deposition In Turbulent Flow, R. Rosmaninho, G. Rizzo, H. Muller-Steinhagen, L. F. Melo
Flow Cell Studies On Fouling Caused By Protein -Calcium Phosphate Deposition In Turbulent Flow, R. Rosmaninho, G. Rizzo, H. Muller-Steinhagen, L. F. Melo
Heat Exchanger Fouling and Cleaning VII
A comparative study of the calcium phosphate fouling process, with and without proteins, was carried out using both standard 316 2R stainless steel and 2R surfaces modified by TiN magnetron sputtering. Fouling behavior was assessed in a heat transfer flow cell operating in the turbulent flow regime. The fouling curves resulting from calcium phosphate deposition in the absence of proteins were substantially different from the ones obtained when protein was present. In this last case, two different fouling periods could be observed. The surface energy of the modified materials was found to affect the deposition parameters (rate of deposition and …
Investigation Of Fouling Process For Convective Heat Transfer In An Annular Duct, Y.C. Chen, Z.H. Quan, C.F. Ma
Investigation Of Fouling Process For Convective Heat Transfer In An Annular Duct, Y.C. Chen, Z.H. Quan, C.F. Ma
Heat Exchanger Fouling and Cleaning VII
Experimental and theoretical study is summarized of fouling process on heat transfer surface. An automatic monitoring system was set up to determine impact of fouling. Experiments were performed with artificial hard water as a working fluid at different conditions. Some important parameters including water temperature, wall temperature, flow velocity, water hardness and alkalinity were testified to make sure their influences on the fouling process on heat transfer surfaces. The ranges of water temperature, wall temperature, flow velocity and water hardness are between 20～50℃, 50～75℃, 0.5～2.0m/s, 200 ～ 1000mg/L (as CaCO3), respectively. All the experimental data were recorded continuously and the …
Bacterial And Protein Adhesion On Ni-P-Ptfe Coated Surfaces, Q. Zhao, C. Liu, Y. Liu, S. Wang
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 …
Fouling Mechanisms By Ab Initio Calculations Condensation Reactions On The Rutile (101) Surface And Adsorption Of Ions On The Cr2o3 Surfaces, E. Puhakka, M. Riihimäki, R.L. Keiski
Fouling Mechanisms By Ab Initio Calculations Condensation Reactions On The Rutile (101) Surface And Adsorption Of Ions On The Cr2o3 Surfaces, E. Puhakka, M. Riihimäki, R.L. Keiski
Heat Exchanger Fouling and Cleaning VII
Molecular modelling approach was utilized to describe detailed fouling mechanism caused by crystallization. The interest was on the heat transfer surfaces, which were manufactured from titanium and stainless steel. With ab initio calculations, the role of the surface oxide layer structure of titanium and stainless steel on fouling was investigated. The surface structure of titanium and stainless steel were assumed to consist of rutile (TiO2) and dichromium trioxide (Cr2O3), respectively. It was found that the inorganic fouling depends strongly on the oxide layer structure and the existence of hydroxyl groups on the surface. Based on the results, two mechanistically different …
Modelling Of Particulate Fouling On Heat Exchanger Surfaces: Influence Of Bubbles On Iron Oxide Deposition., D.H. Lister, F.C. Cussac
Modelling Of Particulate Fouling On Heat Exchanger Surfaces: Influence Of Bubbles On Iron Oxide Deposition., D.H. Lister, F.C. Cussac
Heat Exchanger Fouling and Cleaning VII
Studies of iron oxide deposition on Alloy-800 heatexchanger tubes have been part of a continuing research program at the University of New Brunswick; the present work formulates mechanisms for the effect of bubbles on deposition in water under boiling conditions. To supplement results from earlier deposition experiments in a fouling loop at UNB, measurements of bubble frequency and departure diameter as a function of heat flux were performed. High-speed movies of bubbling air/water systems indicated that a pumping action moved particles from adjacent areas at the surface to bubble nucleation sites. To explain the observations, the model considers deposition and …
Simultaneous Consideration Of Flow And Thermal Effects Of Fouling In Crude Oil Preheat Trains, G.T. Polley, A. Morales Fuentes, D.I. Wilson
Simultaneous Consideration Of Flow And Thermal Effects Of Fouling In Crude Oil Preheat Trains, G.T. Polley, A. Morales Fuentes, D.I. Wilson
Heat Exchanger Fouling and Cleaning VII
Given models linking flow resistance and fouling resistance it becomes possible to simulate the effects of fouling on the hydraulic performance of a refinery pre-heat train. Such a simulation has been used here to identify when plant throughput will be limited by pressure drop; how throughput can be improved through the cleaning of individual exchangers and groups of exchangers; and how much production can be maintained when individual exchangers are taken off-line. Determination of better operating strategy requires a simulation of both hydraulic and thermal performance. In this paper we implement a pragmatic linked model and consider the results from …
Optimization Of Flow Direction To Minimize Particulate Fouling Of Heat Exchangers, M.S. Abd-Elhady, C.C.M. Rindt, A.A. Van Steenhoven
Optimization Of Flow Direction To Minimize Particulate Fouling Of Heat Exchangers, M.S. Abd-Elhady, C.C.M. Rindt, A.A. Van Steenhoven
Heat Exchanger Fouling and Cleaning VII
The influence of flow direction with respect to gravity on particulate fouling of heat exchangers is investigated experimentally to determine the optimal flow direction to minimize fouling. Four orientations of flow have been investigated, horizontal flow, upward flow, downward flow and a flow under an angle of 45°. It is observed that fouling starts at the point of stagnation irrespective of the flow direction, and also at the top of the heat exchanger tubes. Particulate fouling grows from these two points till they meet and the fouling layer covers the whole surface of the heat exchanger tube. Fouling at the …
Incorporation Of A Consideration Of Fouling Into The Design Of Vertical Thermo-Siphon Re-Boilers, G.T. Polley, S.J. Pugh
Incorporation Of A Consideration Of Fouling Into The Design Of Vertical Thermo-Siphon Re-Boilers, G.T. Polley, S.J. Pugh
Heat Exchanger Fouling and Cleaning VII
Two causes of under-performance within the tubes of vertical thermo-siphon re-boilers (VTR’s) are considered: premature dry-out within the unit and chemical reaction fouling at the tube wall. In many cases dryout is itself a cause of fouling. Both of these causes depend on re-boiler geometry. Some geometry performs satisfactorily. Other geometry performs poorly. There are two basic forms of flow boiling: nucleate flow boiling and convective flow boiling. In nucleate flow boiling part of the vaporisation results from the formation of bubbles of vapour on the heated surface. Unfortunately, a thin liquid film (the micro-layer) formed beneath these bubbles can …
A Lagrangian Particle Cfd Post-Processor Dedicated To Particle Adhesion/Deposition, M. Losurdo, C. Bertrand, H. Spliethoff
A Lagrangian Particle Cfd Post-Processor Dedicated To Particle Adhesion/Deposition, M. Losurdo, C. Bertrand, H. Spliethoff
Heat Exchanger Fouling and Cleaning VII
In the past few years the use of biomass in power plants has grown dramatically. As a result of this action fouling and slagging in co-firing biomass facilities have turned out to play a critical role in the efficiency of such facilities. Efficient and effective methods are therefore needed to control fouling to an acceptable level and to prevent economic losses due to reduced furnace thermal efficiency, increased maintenance or even unscheduled outages. Numerical prediction of the impact of deposit properties has proved itself to be a successful strategy to both evaluate changes in the facility performance and to investigate …
Computation And Evaluation Of Wall Shear Stress Distribution At The Lower Surface Of A Radial Flow Cell, J. G. Detry, B. B. B. Jensen, C. Deroanne, M. Sindic
Computation And Evaluation Of Wall Shear Stress Distribution At The Lower Surface Of A Radial Flow Cell, J. G. Detry, B. B. B. Jensen, C. Deroanne, M. Sindic
Heat Exchanger Fouling and Cleaning VII
In the present work, the flow in the radial-flow cell was analyzed for an aspect ratio of 1 with inlet pipe Reynolds numbers of 950, 2 000 and 4 100. Two models were applied to compute the wall shear stress distribution at the lower surface, at any distance from the center. Stainless steel and polystyrene surfaces were soiled with oil and starch and the detachment of these soils was assessed by measuring the detachment radius in a radial-flow cell. The experimental radii were introduced in the models and converted into wall shear stress. Comparisons of the various sets of data …