Operations Research, Systems Engineering and Industrial Engineering Commons^™

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 …

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

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

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

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

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

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 …

A Survey Of Alfa Laval’S Experience Of Fouling Prevention In Plate Heat Exchanger Systems, A. Tornqvist

Heat Exchanger Fouling and Cleaning VII

This paper will present some aspects on and experiences of fouled plate heat exchangers in industrial applications as well as the present status on a new tool to monitor heat exchanger performance and to predict future cleaning procedures.

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 …

Effect Of Thermal Contact Resistance On The Heat Transfer In Plate Finned Tube Heat Exchangers, D. Taler

Heat Exchanger Fouling and Cleaning VII

Plate fin-and-tube heat exchangers are made by inserting oval tubes through sheet metal strips with stamped holes and then expanding the tubes slightly to cause pressure at the tube-to-strip contacts. The gap between the fin base and the outer tube surface may be filled with air or corrosion products causing a decline in the ability of plate fins to transfer heat. The contact resistance must be accounted for in the design and performance calculations of heat exchangers. In this paper, the thermal contact resistance of the fin-to-tube attachment is estimated from the condition that the dimensionless correlations for the Colburn …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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.

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 …

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 …

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 …

Acuta Enews July 2007, Vol. 36, No. 7

ACUTA Newsletters

ln This lssue

Meet the Board for 2007-08

From ACUTA Headquarters: Member Anniversaries............... Jeri A. Semer, CAE, Executive Director

Tech Talk: The Passing of Passwords................... Kevin Tanzillo, Dux PR

DC Update .................. Jeanne Jansenius, Sewanee, The University of the South

Check lt Out: RFls/RFPs, Job Postings, Press Releases

Board Report ................. Riny Ledgerwood, Son Diego State Univ., ACUTA Sec./Treasurer

FYI: Useful lnformation from the campus............... Student Monitor

Level 3 Completes lnternet2 Optical Network implementation

Member Sites to See

lnfo Links................... Randy Hayes, Univ. of Northern lowa

Terri Robinett Wins Room at the Conference

$5250,000 Emergency & Event Notification "Grants,, from …

Cover Page, 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

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 …