Industrial Engineering Commons^™

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 …

Comparison Of Crude Oil Fouling Using Two Different Probes, A. P. Watkinson

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

A variety of different fouling rigs, each with its own advantages and disadvantages is available to assess crude oil fouling. In this research, fouling of three crude oils are compared, using two electrically heated annular probes with strikingly different modes of operation. The Hot Liquid Process Simulator (HLPS) was operated in single-pass mode, under creeping flow conditions for time durations of a few hours at constant surface temperature. The Portable Fouling Research Unit (PFRU) was operated at velocities a factor of 250 higher, and followed the fouling process over two or more days at constant heat flux, using re-circulation of …

Improvements And New Developments In Self-Cleaning Heat Transfer Leading To New Applications , Dick G. Klaren

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Improvements in the design have made the fluidized bed heat exchanger better suitable for the revamp of existing vertical severely fouling heat exchangers in evaporators, crystallizers and reboilers into a self-cleaning configuration. Highly viscous non-Newtonian slurries used in mineral processing can benefit from the fluidized bed heat exchanger not only due to its self-cleaning performance, but also as a result of the shear-thinning action of the fluidized particles which dramatically lowers the viscosity of the slurry. New developments have created the possibility to design compact self-cleaning fluidized bed heat exchangers which can compete with plate and frame exchangers.

An Effective Cip Procedure For Removing Dairy Protein Based Deposit – A Laboratory Investigation, Xiao Dong Chen, Necati Özkan, Frank Qin, Hong Xin, Lin Lin

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

In this paper, examples of using an in-situ electrochemical cleaning technique are illustrated. It can be shown that while using the standard chemical for cleaning in the dairy industry, the application of the in-situ electrochemical method is very effective in removing the dairy protein based fouling deposits. Both the gel protocol developed earlier and the real fouling procedure have been used to evaluate the effectiveness of the new method.