Fouling Research Articles

【Original Contribution】 Response of Zeta Potential to the Fouling during Microfiltration of Surfactants

【Original Contribution】 Response of Zeta Potential to the Fouling during Microfiltration of Surfactants

Effect of processing parameters on the microfiltration fouling during the clarification of pomegranate juice.

The pomegranate juice with high nutritional value has turbid appearance that makes it difficult to preserve and concentrate. Microfiltration is useful process which can clarify it. One of the most important problems in this process is fouling phenomenon which affected by several parameters. The effects of fluid velocity, transmembrane pressure, membrane type and its pore size on membrane fouling were studied. The results showed that the membrane fouling increased with increase in the fluid velocity and transmembrane pressure. Also, more hydrophilic property and pore size resulted more membrane fouling due to greater flux which move more particles to membrane surface. Scanning electron microscopy (SEM) images support these results. Keywords: Clarification, Fouling, Membrane, Pomegranate juice

PRI-SC® Sulfide, Phosphorus and UV Fouling Improvements at Raleigh, NC

PRI-SC® Sulfide, Phosphorus and UV Fouling Improvements at Raleigh, NC

Industrial Aspects of Fouling

Die Erforschung ionischer Flussigkeiten und die Erschliesung von neuen Anwendungsgebieten dieser Stoffklasse haben in den letzten Jahren deutlich zugenommen. Die einzigartigen physikalischen und chemischen Eigenschaften dieser Verbindungen machen sie ebenfalls fur eine Verwendung im Bereich der Pumpentechnik sehr attraktiv. Der Vortrag berichtet zunachst uber relevante Parameter wie Kompressibilitat, thermische Stabilitat, Korrosivitat, Schmiereigenschaften und die Verschleisbestandigkeit der ionischen Flussigkeiten. Aufbauend darauf wird der Einsatz von ionischen Flussigkeiten in verschiedenen Maschinen dargestellt. Beispielhaft dafur ist der Ersatz von Wasser durch ionische Flussigkeit als Betriebsmedium in einer Flussigkeitsringvakuumpumpe und die Verwendung als Hydraulikflussigkeit in einer Kolbenmembranpumpe. Im Fokus der Untersuchungen bei der Flussigkeitsringvakuumpumpe standen der minimale Ansaugdruck und die Kennlinienveranderungen. Die Kennlinie fur inoische Flussigkeiten im Vergleich zu Wasser zeigt eine deutliche Verbesserung. Der minimale Ansaugdruck fallt dabei von etwa 60 mbar mit Wasser auf unter 10 mbar (s. Abb.). Auserdem wurden im Hinblick auf den realen Betriebseinsatz das akustische Maschinenverhalten und die damit in Zusammenhang stehenden Kavitationserscheinungen sowie die Zusammensetzung des Abluftstromes und die Leistungsaufnahme im Vergleich zum klassischen Betrieb ermittelt. Bei der Kolbenmembranpumpe steht die Verbesserung des Pumpenwirkungsgrades im Vordergrund der Untersuchungen. Die experimentell erhaltenen Ergebnisse werden prasentiert und die Eignung von ionischen Flussigkeiten als Betriebsmedium in Vakuummaschinen und Kolbenmembranpumpen diskutiert.

FOULING

FOULING

Analysis of Deposits to Study the Effect of Particles on Crystallisation Fouling

Understanding the process of fouling is of utmost importance considering its usually considerable impact on the overall performance of a process plant. Crystallisation fouling is one of the most commonly encountered problems in industry. Despite significant advances made by crystallographers in understanding mechanisms of crystallisation, researchers working in the filed of fouling in heat exchangers have tended to ignore certain basic features of crystallization. Generally the rate of crystallization fouling is simply taken as a function of concentration difference occurring in heat exchangers and reaction rate constant. The aim of this study was to analyse crystalline deposits forming on the heat transfer surface and hence determine the effect of particles on crystallization fouling. It was found that deposit formation pattern changed significantly when particles of the crystallizing material were introduced into the process solution. These particles settled on the heat transfer surface and provided new nucleation sites for crystal growth. As a result, many additional crystals were formed and the rate of crystallization enhanced significantly. In contrast, particulate fouling by these particles was found to be insignificant. Based on these results, it is argued that there is a need to modify the crystallization fouling models to incorporate the enhancement effects of the particles.

Physicochemical basis of fouling prediction and prevention in the process industry

In this report the physicochemical principles of deposition and fouling of heavy organics and other compounds are presented and discussed. The basic requirements for predictive modeling and mitigation of fouling in industrial processes are presented. The possible mechanisms of fouling in various processes are discussed in light of the general principles of fouling known and the available industrial processes fouling data. The various stages of fouling and the fouling prediction modeling requirements for those stages in industrial processes are specified and the data requirements for each stage are presented. Parameters influencing the fouling are specified and the foundations for predictive model1ing, which will help to mitigate fouling and increase the useful life of processes, are specified.

Evaluation of membrane fouling by electical and surface chemical composition measurements

La adsorcion de macromoleculas cargadas sobre la superficie de una membrana en procesos de microfiltracion produce la colmatacion (o ensuciamiento) de la membrana y, por tanto, una disminucion del flujo a traves de la membrana. La colmatacion puede ser facilmente detectada por la variacion de: i) parametros electroquimicos como la resistencia electrica y la permeabilidad salina, directamente relacionados con la porosidad de las membranas; ii) las concentraciones atomicas de los elementos caracteristicos de la superficie de la membrana, determinadas mediante espectroscopia de fotoelectrones de rayos X (XPS). Para membranas comerciales de alumina (Anopore., 0.1 �Em de tamano de poro) en contacto con disoluciones que contienen 0.5 g/l de seroalbumina de bobino (BSA), los parametros electroquimicos indican una disminucion en la porosidad de la membrana del 50%, aproximadamente, despues de estar 72 h en contacto con una disolucion con proteina. Los resultados de XPS indican: i) que la capa de proteina adsorbida sobre la superficie de la membrana no aumenta linealmente con el tiempo de interaccion membrana-proteina, sino que se produce fundamentalmente durante las primeras 24 h.; ii) la no uniformidad de la capa de proteina adsorbida sobre la membrana de alumina.

An Experimental Study of Fouling Effect on the Heat Transfer Around a Tube in Staggered Tube Banks

An experimental study has been performed to investigated the forced convection heat transfer characteristics of 6 circular cylinders in staggered arrangement in a cross flow of air. The water scale deposited on condenser wall of power plant was used to investigate the effect of roughness of scaled surfaces. The relative roughness*average diameter of scale/cylinder diameter) was in a range of k/d=0.0066, 0.0111, 0.0167, 0.0222 and 0.0278. The cylinder spacings(L/d) varies from 1.5 to 4.0 where L denote the cylinder spacings along and normal to the upstream uniform flow direction. The Reynolds number was varied in a range of 10, 000 Re 50,000. The local and mean Nusselt numbers were investigated as a function of scale roughness, the cylinder spacing and Reynolds number. The results are compared with those of clean cylinder and inline tube bank, subsequently the mean fouling resistance over the entire circumference was estimated from those results as a function of scale roughness, the cylinder spacing and Reynolds number.

98/00431 Fouling and corrosion in straw and coal-straw fired USC plants

98/00431 Fouling and corrosion in straw and coal-straw fired USC plants

Particulate Two-Phase Flow Analysis for Fouling Prediction(I)-Design of Hot Wind Tunnel and Its Performance Experiment-

We designed the hot wind tunnel to reproduce the conditions of utility boiler and carried out its performance test, in order to investigate the particulate two-phase flow behaviour, the fouling and heat transfer characteristics to the heat exchanger. The hot wind tunnel introduces the control system to control the temperature in the test section. The particle is injected into the hot gas stream. The fouling probe (cylindrical tube) is positioned normal to the particulate gas-particle two-phase flow and cooled by the air. The temperature of gas and cooling air, and temperature in the fouling probe are measured as a function of time, giving the local and averaged heat transfer and fouling factor. The shape of particulate deposition adhered to the fouling probe is also observed.

The effect of the shear-rate dependent thermal conductivity of non-Newtonian fluids on the heat transfer enhancement

The present study investigates the effect of the shear rate-dependent thermal conductivity of non-Newtonian fluids on the heat transfer enhancement in a pipe flow. An axially-constant heat flux boundary condition was adopted in the thermal fully developed region. The present analytical results of Nusselt numbers for various non-Newtonian fluids show heat transfer enhancement over those of a shear rate-independent thermal conductivity fluids. The present analytical results showed good agreement with the previous experiments which excluded the temperature-dependent viscosity effect on heat transfer. This study also proposes the use of a shear rate-dependent thermal conductivity fluids in the design of a heat exchanger for heat transfer enhancement as well as reduction of fouling.

Treatment prevents resin-bead fouling

Treatment prevents resin-bead fouling

Protection of seagoing ships from fouling

Protection of seagoing ships from fouling

Sargassum Tannin, an Antibiotic which Retards Fouling

Sargassum Tannin, an Antibiotic which Retards Fouling

The Wave-Cancelling Effects of Waveless Bulb on the High Speed Passenger Coaster M/S “KURENAI MARU”

This is the second one of the three connected papers. This part concerns the full-scale experiment on the high speed passenger coaster M/S “KURENAI MARU”, where a comparison is made between two different hull forms with and without the attached large bulb, which was specially designed according to the Waveless Form Theory.Descriptions are made on the results of the turning test and the so-called serpentine test (zigzag test) as well as on the ordinary speed trials.Besides a small amount of unexpected bottom fouling effeets upon the hull resistance, coincidence is satisfactorily good between the tank predictions (refer to the First Report) and the trial results.Concerning the manoevering characteristics, the attached large bulb F 4 has demonstrated itself as effective in decreasing somewhat the values of K' and T', where K', T' are the dimensionless indices of manoeverability, recently. introduced by Prof. Nomoto.

Balanus Fouling of Shrimp

Balanus Fouling of Shrimp