Engineering Commons^™

Deposition Of Na2Co3 In Supercritical Water Oxidation Systems And Its Mitigation, M. S. Khan, S. N. Rogak

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Supercritical water oxidation is a technique to destroy wet organic waste. The oxidation reaction takes place at high temperature and pressure. Organics are miscible at these conditions but inorganic salts are not soluble and present fouling problems. Examples of these salts are sodium sulfate and sodium carbonate.

Research is being done in the University of British Columbia to study the fouling behavior of Na₂CO₃ in the SCWO reactor. The working fluid is heated by passing alternating current through the reactor wall. Since the tube surface was hotter than the bulk fluid, the salt was expected to nucleate …

Physical Water Treatment For The Mitigation Of Mineral Fouling In Cooling-Tower Water Applications, Young I. Cho, Sunghyuk Lee, Wontae Kim, Sangho Suh

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

The physical water treatment (PWT) device is defined as a non-chemical method of water treatment utilized for the purpose of scale prevention or mitigation. Three different PWT devices, including permanent magnets, solenoid coil device, and high-voltage electrode, were used under various operating conditions. The present study proposed a bulk precipitation as the mechanism of the PWT and conducted a number of experimental tests to evaluate the performance of the PWT. The results of fouling resistances obtained in a heat transfer test section clearly demonstrated the benefit of the PWT when the PWT device was configured at an optimum condition. The …

Direct Measurement Of The Forces Required To Disrupt And Remove Fouling Deposits, W. Liu, Z. Zhang, G. K. Christian, P. J. Fryer

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

In cleaning, the force required to disrupt the deposit and remove it from the surface tends to be inferred from flow data, rather than being known directly. A novel micromanipulation technique has been developed to measure directly the adhesive strength of food fouling deposits on a stainless steel surface. A T-shaped stainless steel probe pulls fouling deposits away from the surface to which they are attached. The apparent adhesive strength between the fouling deposits and the substrate can be measured as the work required to remove the deposits per unit area from the substrate. Tomato pastes and whey proteins have …

Analysis And Steps To Mitigate Heat Exchanger Fouling In An Aromatics Plant, Shinji Isogai , Mitsutaka Nakamura

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

A heat exchanger, upstream a distillation tower for the separation of BTX (benzene, toluene, xylene) from crude benzene in an aromatics plant, experiences heavy fouling. The fouling mechanism and countermeasures to mitigate or eliminate it, were investigated. An Alcor Hot Liquid Process Simulator (HLPS)was used for the fouling rate measurement. The main mechanism is a combination of precipitation fouling and chemical reaction fouling. Effects, such as temperature, vapor ratio (vapor mole fraction of the fluid), heater materials, surface roughness and the addition of some different types of chemicals were studied. From the experiments, some countermeasures for this fouling were proposed. …

The Balance Between In The Cleaning Of Milk Fouling Deposits, G. K. Christian , P. J. Fryer

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Deposits formed on the surface of heat treatment equipment in the dairy industry compromise product quality and process efficiency. Frequent cleaning is needed to ensure consumer safety and optimal process operation. Cleaning solutions generally have a high environmental impact; the need is to minimize their use. We have studied the physics and chemistry of cleaning at two length scales of measurement: (i) the effect of cleaning chemical and water on deposits within a plate heat exchanger (PHE), and (ii) the effect of process variables on small fouled disks. The chemical nature of cleaning of dairy deposits is shown clearly by …

Retrofitting Crude Oil Refinery Heat Exchanger Networks To Minimise Fouling While Maximising Heat Recovery, B. L. Yeap, D. I. Wilson, G. T. Polley, S. J. Pugh

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

The use of fouling factors in heat exchanger design and the lack of appreciation of fouling in traditional pinch approach has often resulted badly designed crude preheat networks that are expensive to maintain. The development of thermal and pressure drop models for crude oil fouling has allowed its effects to be quantified, so that techno-economic analyses can be performed and various design options compared. Application of these fouling models is carried out on two levels: on the assessment of adding extra area to individual exchangers, and the design of a complete network using the Modified Temperature Field Plot. Application to …

Heat Treatment Improvement Of Dairy Products Via Ohmic Heating Processes : Thermal And Hyrodynamic Effect On Fouling, M. A. Ayadi, L. Bouvier, F. Chopard, M. Berthou, J. C. Leuliet

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Fouling and consequently cleaning of heat exchangers in the dairy industry are nowadays a significant issue still not solved for the processing of quite a large variety of products. Ohmic heating processes for food products a priori are well known to minimize the fouling phenomenon due to a totally different way of heating food by admitting the current directly in the product. Such a technology could be a good alternative to counter both fouling and cleaning aspects when pasteurizing or sterilizing dairy desserts known to generate large amounts of soil on heated surfaces. The aim of this experimental study was …

Removal Of Particles From A Powdery Fouled Surface Due To Impaction, M. S. Abd-Elhady, C. C.M. Rindt, J. G. Wijers, A. A. Van Steenhoven

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Particulate fouling is defined as the unwanted deposition of particles on heat exchange surfaces. The fouling layer reduces the heat transfer rate and leads to inefficient operation. The net fouling rate is the result of the difference between the deposition rate and the removal rate of particles. One of the mechanisms that contribute to the removal of particles from powdery fouled surfaces is the collision of an incident particle with the fouled surface. In the present study, removal of particles from powdery fouled surfaces due to an incident particle impact is studied numerically and experimentally. A numerical model is developed …

Chemical Cleaning Of Oil Refinery Heat Exchangers -- The Need For A Joint Effort, Himanshu M. Joshi, Glen Brons

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

One component of the high cost of fouling to oil refineries is the maintenance money spent to clean fouled heat exchangers and the associated lost production while the exchanger is out of service. This presentation will highlight some specific fouling situations in oil refineries which can benefit from chemical cleaning. Cooperative efforts are needed between refinery operators, researchers, and chemical suppliers to develop the proper solvents and to find the optimum procedures to use them for cleaning.

Fouling Of Some Canadian Crude Oils, M. Srinivasan , A. P. Watkinson

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

A thermal fouling study was undertaken using three sour Canadian crude oils. Experiments were carried out in a re-circulation fouling loop, equipped with an annular (HTRI) electrically heated probe. Fluids at pressures of about 1000-1340 kPa under a nitrogen atmosphere were re-circulated at a velocity of 0.75 m/s for periods of 48 hours, and the decline in heat transfer coefficient followed under conditions of constant heat flux. Bulk temperatures were varied over the range 200-285°C, and initial surface temperatures from 300 to 380°C. Heat fluxes were in the range of 265-485 kW/m².

Preheat Train Crude Distillation Fouling Propensity Evaluation By The Ebert And Panchal Model, M. Bories , T. Patureaux

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

The Ebert and Panchal fouling model was used to assess the fouling tendency of the exchangers of an industrial crude distillation unit (CDU) preheat train. The ranking obtained through a monitoring and processing of the performances of the different exchangers matched quite well the predictions of the Ebert and Panchal fouling model. In the meantime, a first mitigation solution consisted in periodically cleaning heat exchangers and installing TURBOTAL^TM tube inserts. Through the fouling monitoring of the equipped exchangers, the beneficial action of the TURBOTAL^TM inserts is also made quite clear.

A Mathematical Model Of The Removal Of Milk Protein Deposit, Hong Xin, Xiao Dong Chen, Necati Özkan

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Based on a polymer dissolution controlled chemical cleaning mechanism, a mathematical model has been developed to describe the different stages of the removal of milk protein fouling from a hard surface. Various processes, such as reptation, disengagement, mass transfer through the boundary layer and surface area changes during the decay cleaning stage have been taken into account in the modelling process. The successful prediction of the cleaning process under various conditions indicates that the model has proposed a rational mechanism accounting for the removal of milk protein fouling.

Challenges In Cleaning: Recent Developments And Future Prospects, D. I. Wilson

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

There is considerable scope for optimisation of processes subject to fouling by effective management of cleaning. The cleaning cycle starts with the (often-complex) material generated during the fouling cycle. The nature of the deposit determines the most appropriate cleaning method, which can often be optimised significantly via knowledge of the key mechanisms involved in deposit removal. Links between deposit ageing and cleanability need to be established and quantified. There is a wide range of cleaning methods available, and attention is focused here on cleaning-in-place (CIP) techniques. Modern instrumentation allows cleaning (and deposit materials behaviour) to be probed to greater degree …

Fouling Characteristics Of A Light Australian Crude Oil, Zaid S. Saleh, R. Sheikholeslami, A. P. Watkinson

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Australian crude oils, which generally contain little asphaltenes, nevertheless give rise to fouling in refinery pre-heat trains. In this research, fouling of a series of such crude oils and their blends is being assessed. The present work focuses on thermal fouling resulting from heating Gippsland crude oil at moderate temperatures. The oil is maintained under nitrogen at a pressure of 379 kPa, and re-circulated at bulk temperatures of 80-120°C through an electrically heated annular probe at velocities in the range 0.25 to 0.65 m/s with surface temperatures from 180-260°C. Experiments are run for periods up to 90 hours at constant …

Study Of Whey Protein Adsorption Under Turbulent Flow , Olga Santos, Tommy Nylander, Gerhard Rizzo , Hans Müller-Steinhagen, Christian Trägårdh, Marie Paulsson

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Reducing fouling in heat exchangers during treatment of milk products is one of the great challenges in the dairy industry. One approach to mitigate fouling is to alter the surface characteristics of the heat exchangers making them less prone to protein adsorption. On this background the European project MODSTEEL was established to study the use of new modified stainless steel surfaces to control fouling of milk components. This part of the project focuses on the adsorption of b-lactoglobulin (b-Lg) from a whey protein solution on unmodified and modified 316 2R stainless steel surfaces by in situ ellipsometry under well-defined flow …

Measurement And Modeling For The Mitigation Of Organic Crystallization Fouling, Shinji Isogai, Mitsutaka Nakamura, Hirofumi Inokuchi, Hiroaki Kimura, Yoshio Koga

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

One of the aromatic compound plants in Mitsubishi Chemical Corporation has a heavy crystallization fouling problem. In order to solve this problem, using a low power gamma ray sensor, we found the location of heaviest fouling and measured the fouling growth rate. We also made a crystallization fouling laboratory test unit (simulator) to study the effects of some factors, such as temperature, liquid velocity, surface roughness and liquid composition. Fouling rates of the industrial plant cooler and the laboratory fouling test unit were modeled using a combination of Kern-Seaton and Reitzer models. However, the parameters of the plant and test …

Numerical Simulation Of The Fouling On Structured Heat Transfer Surfaces (Fouling), Fahmi Brahim, Wolfgang Augustin, Matthias Bohnet

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

The objective of this work is to make a contribution to a good and fast prediction of the crystal growth on flat and structured heat transfer surfaces. For the numerical simulation the CFD code Fluent is used. The simulation enables an unsteady calculation of the fouling process and a realistic description of the temporal modification of the flow and temperature fields due to the continuous crystal growth. The numerical simulation of the crystal growth is based on models for the calculation of the deposition (Krause, 1993) and removal (Bohnet, 1990) mass rates. Based on experimental results of Hirsch (Bohnet et. …

The Early Stages Of Deposition Of Magnetite Particles Onto Alloy-800 Heat Exchange Surfaces Under Subcooled Boiling Conditions, Norman Arbeau, William Cook , Derek Lister

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

The data collected during experiments in water loops on the fouling of heat exchange surfaces with magnetite particles often display a dip in the deposit accumulation curve at about 10 – 20 hours into the experiment. Generally the dips are small enough to be considered part of the scatter and may not even be discernible in long runs with considerable amounts of deposit. We have examined this phenomenon in a series of short experiments lasting up to a maximum of 40 hours. The test section of the recirculating water loop used for the study contained a heat exchanger tube of …

Identification And Testing Of Amines For Steam Generator Corrosion And Fouling Control, S. J. Klimas, K. Fruzzetti, C. W. Turner, P. V. Balakrishnan, G. L. Strati , R. L. Tapping

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

AECL and EPRI have been evaluating candidate amines for control of corrosion and fouling in recirculating nuclear steam generators. To permit an unambiguous ranking of the suitability of the candidate amines, the characteristics of base strength, volatility, price, steam generator fouling, cost of associated condensate and blowdown polishing, toxicity and ecotoxicity have been summarized in a single numerical index. The majority of the data required for the calculation of the index is available in the literature. The effect of amine on steam generator fouling has been measured using a recirculating loop at AECL under flow boiling conditions. The loop results …

Fouling Enhancement Under Flow Boiling At Elevated Steam Qualities, S. J. Klimas, J. M. Pietralik, K. Fruzzetti , R. L. Tapping

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Under laboratory conditions of flow boiling in water at 272–285°C (5.7 to 7.0 MPa), it has been observed that fouling rates by colloidal iron oxides ("crud") dramatically increase upon reaching a certain steam quality and mixture velocity. In loop tests, an increase in fouling rates by up to 3 orders of magnitude was repeatedly observed. This effect is called here “heavy fouling under elevated steam quality” (HFESQ).

HFESQ is potentially very significant for once-through steam generators, and very large versions of recirculating nuclear steam generators, because it can lead to heavy fouling in the upper tube bundle.

The mechanism of …

Understanding And Quantifying Cleaning Processes Using Fluid Dynamic Gauging, J. Y. M. Chew, S. S. S. Cardoso, W. R. Paterson, D. I. Wilson

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Computational fluid dynamics (CFD) has been used to analyse the flow patterns generated by the fluid dynamic gauging (FDG) technique in order to allow that technology to give simultaneous measurements of fouling layer thickness and incipient strength (via breakage). Stress field predictions were generated by solving the governing Navier-Stokes equations for these quasi-laminar flows using the numerical solver Fastflow^TM and validated by comparison with experimental hydrostatic pressure data. Enhanced FDG was used to study the removal of a tomato paste soil, which had been characterised by Liu et al. (2002) using a micro-manipulation technique. Deposit strength measurements gave clear …

The Practical Application And Innovation Of Cleaning Technology For Heat Exchangers, George E. Saxon Jr., Richard E. Putman

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

The fouling of heat exchangers not only has a negative impact on heat transfer efficiency but also may restrict the output or production capacity of the facility. Given the cooling medium and the process, heat exchangers may be lightly fouled with organic deposits or may be severely blocked from hardened process chemicals. The probability of success in cleaning the heat exchanger is dependent on the selection of the appropriate cleaning technology under the specific fouling conditions. Early identification of fouling characteristics and a fundamental knowledge of cleaning system capabilities are essential in determining the most effective cleaning technology and the …

Fouling Mitigation Using Helixchanger Heat Exchangers, Bashir I. Master, Krishnan S. Chunangad, Venkateswaran Pushpanathan

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

One of the major indeterminates in the design as well as operation of heat exchangers is the rate of fouling a select heat exchanger geometry would exhibit over the operation cycles. Gradual deterioration of heat exchanger performance due to the accumulation of fouling film on the heat transfer surface is often accounted for in the form of a fouling resistance, or commonly known as the fouling factor, while determining the heat transfer surface required for a specific heat duty. More often, the fouling mechanism responsible for the deterioration of heat exchanger performance is flow-velocity dependent. Maldistribution of flow, wakes and …

Overview Of Actual Methods For Characterization Of Ash Depostion, Ch. López, S. Unterberger, J. Maier, K. R. G. Hein

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Utility operation with frequent fuel switching is a common practice, forced by cheaper coal availability in the international market. Additionally, a substitution of coal by cheaper local secondary fuels, ranging from forest wood to sewage sludge and industrial or domestic residues, is gaining importance. Switching between different fuels, even if these do not differ much from the design coal, enhances operational problems arising from ash deposition. In order to prevent operational problems, through comprehension of the phenomena taking place within the furnace, appropriate sampling and characterization of the deposits are necessary. Methods commonly used for analysis of ash deposits and …

Biocide Dosing Strategies For Biofilm Control, D. M. Grant , T. R. Bott

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

In order to reduce environmental impact of biocide use for the control of biofilm formation in cooling water circuits, “environmentally friendly” biocides have been developed, but they are generally more expensive than the more traditional chemicals. It is imperative therefore, that the minimum quantity of biocide is employed, so that costs are kept to a minimum. To achieve this objective optimum dosing strategies are required. Using apilot plant in conjunction with a monoculture of Pseudomonas fluorecsens as the biofouling bacterium, tests were carried out using a proprietary biocide, to investigate the effects of dose concentration, duration and frequency of dosing …

Development Of A Data-Based Method For Performance Monitoring Of Heat Exchangers, A. Sawyer, A. E. Ruggles, B. R. Upadhyaya, E. Eryurek, K. Kavaklioglu, J. Miller

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

A multivariate analysis method is developed for processing measurements, and for detecting and isolating faults and monitoring performance degradation in heat exchanger control loops. A heat exchanger inside a typical temperature to flow cascade loop is considered. This system includes a constant speed pump with flow control valves, pressure and temperature measurement. A proportional-integral-differential (PID) controller is used to maintain a temperature set point for the exit flow on one side of the exchanger. A thermal-fluid model for the components in the system is developed. A Fault Detection and Isolation (FDI) rule-base is formulated from results of simulations performed using …

Table Of Contents, The Editors

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

No abstract provided.

Bayer Process Heat Exchangers Cleaning Efficiency: Optimizing The Acid Dissolution Of Sodalite Scale, Sébastien Fortin , Raymond Breault

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Aluminum metal is produced by the electrolytic reduction of aluminum oxide (Al₂O₃), mainly extracted from bauxite ore digested in a hot caustic soda solution. This solution is supersaturated with respect to sodium aluminate and silicate, which react together to form sodalite (3[Na₂O·Al₂O₃·2SiO₂ ·2H₂O] ·Na₂CO₃) at high temperatures. Heat exchanger tubes are scaled with this compound, which seriously reduces heat transfer coefficient, thus increasing energy costs.

Heat exchanger tubes are cleaned periodically with a sulfuric acid solution that contains a corrosion inhibitor. An investigation …

Fouling And Cleaning Of Modified Stainless Steel Plate Heat Exchangers Processing Milk Products, M. Beuf, G. Rizzo, J. C. Leuliet, H. Müller-Steinhagen, S. Yiantsios, A. Karabelas, T. Benezech

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Fouling of heat exchangers in dairy industries is still quite a severe problem both technically and economically. Altering the surface properties of the heating surfaces would be a way of solving this issue.

Modified steel surfaces were tested in an Alfa Laval V2 plate heat exchanger throughout dairy product sterilization. The behavior was analyzed for 8 different surface treatments, such as coatings (Diamond Like Carbon [DLC], Silica, SiO_X, Ni-P-PTFE, Excalibur^®, Xylan^®) and ion implantation (SiF+, MoS₂).

All fouling and cleaning experiments were carried out in standard and well-controlled operating conditions. After fouling, …

Analysis Of Fouling Data Based On Prior Knowledge, M. R. Malayeri , H. Müller-Steinhagen

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Conventional regression methods are generally unable to analyse extremely complicated processes involving a considerable number of independent variables with poorly understood interaction. These methods use a defined equation for which the parameters of this equation have to be determined. It is however questionable whether any arbitrarily chosen equation is the best. This study aims to implement the powerful neural network architecture for a comprehensive data bank. The HTRI data bank contains a large and unique set of experimental data for cooling water fouling. Only a selection of the data bank is being used at the present time, due to the …