Showing papers on "Fouling published in 1993"
TL;DR: The evidence for fouling both on the membrane surface and within the membrane pores is described, and the effect of the feed properties, membrane properties and the operating conditions on membrane behaviour and fouling are discussed.
468 citations
TL;DR: In this paper, the authors obtained experimental data for the flux decline during the stirred cell filtration of different commercial preparations of bovine serum albumin (BSA) through asymmetric polyethersulfone microfiltration membranes.
171 citations
TL;DR: In this article, the authors reported on the perception of fouling in New Zealand based on 200 companies and the application of nearly 2000 heat exchangers and made an attempt to provide a reasonably reliable estimate of the annual fouling-related costs.
Abstract: Data are reported on the perception of fouling in New Zealand based on 200 companies and the application of nearly 2000 heat exchangers These data are discussed with respect to their occurrence for various heat exchanger applications, industries, and heat exchanger types The fouling mitigation strategies applied in New Zealand are depicted and compared with the state of the art in fouling mitigation as found from an extensive literature search Some comments are made as to the heat exchanger cleaning frequencies in New\Zealand industries Finally, an attempt is made to provide a reasonably reliable estimate of the annual fouling-related costs in New Zealand These results are then compared with those previously reported from the United States and England
163 citations
TL;DR: In this article, preadsorption of hydrophilic polymers on hydrophobic ultrafiltration membranes can reduce the susceptibility of the modified membranes to protein fouling, and the mechanisms of this anti-fouling action were investigated.
162 citations
TL;DR: In this article, the authors developed equations for the blocking laws (complete, standard and intermediate) at a constant flow rate and derived a general expression related to the instantaneous hydraulic permeability of the deposit d t /(Δ P ).
142 citations
TL;DR: In this article, the amount of deposit is considered to be proportional to the volume of fluid that is hot enough to produce denatured and aggregated protein, and it is shown that bulk processes are important in whey protein fouling.
136 citations
TL;DR: In this article, the Navier-Stokes equations for azimuthal flow in an annulus with a porous wall on the rotating inner cylinder are solved for the narrow-gap approximation and with several other reasonable simplifications.
132 citations
TL;DR: In this article, the effect of organic matter adsorption on ultrafiltration membrane blocking and fouling was examined using synthetic, particle free solutions of a low molecular weight dextran and tannic acid.
105 citations
TL;DR: In this article, the effects of flow velocity, wall temperature, and CaSO 4 concentration on the fouling rates have been investigated and the distribution of scale along the heat transfer surface has been observed.
Abstract: Crystallization fouling of calcium sulfate was investigated in a plate and frame heat exchanger. The effects of flow velocity, wall temperature, and CaSO 4 concentration on the fouling rates have been investigated and the distribution of scale along the heat transfer surface has been observed. The measured fouling curves are compared with predictions from a surface reaction controlled model
99 citations
TL;DR: The relationship between membrane fouling and cleaning was investigated in terms of flow conditions, transmembrane pressures, pH, membrane properties, and cleaning agents using a stirred batch cell and aqueous albumin solution and membranes with partial permeability showed a greater tendency for fouling.
82 citations
TL;DR: In this paper, the relationship between spacer characteristics and fouling was investigated and it was shown that the spacer's ability to reduce concentration polarization is the main fouling control factor.
TL;DR: In this paper, the authors studied the mechanisms of membrane fouling and the effects of properties and structure of the adsorbed-protein layer on membrane degradation using bovine serum albumin (BSA) and β-lactoglobulin (β-LG) as test proteins, and poly(vinylpyrrolidone)-coated polycarbonate (PC) and regenerated cellulose (RC) as membranes.
TL;DR: The first layer of deposit formed after 4 s of contact between the fluid and the surface (fluid temperature 68 and 73 °C), consisted mainly of protein and was identified by X-ray photoelectron spectroscopy analysis.
Abstract: Fouling from milk fluids is a severe industrial problem which reduces the efficiency of process plant. The chemistry of fouling has been thoroughly investigated but the sequence of events that occur is not yet clear. Deposit contains both protein and minerals. Experiments have been carried out to determine the sequence of events in the fouling of stainless steel surfaces at 96 °C from turbulent flows of whey. Contact times between 4 and 210 s have been studied, and surface analysis techniques used to detect the distribution of elements. The first layer of deposit, formed after 4 s of contact between the fluid and the surface (fluid temperature 68 and 73 °C), consisted mainly of protein and was identified by X-ray photoelectron spectroscopy analysis. There was a lag phase of up to 150 s for a fluid temperature of 73 °C before deposit aggregates were observed to adsorb on to the surface. These aggregates were identified as protein and Ca by X-ray elemental mapping. No P was found in any experiments for this exposure. After 60 min contact time, however, both Ca and P were found at the interface between deposit and the stainless steel surface, irrespective of the Ca and P content of the test fluid.
TL;DR: In this article, an operating mode with dynamic counter pressure (recirculation of the permeate co-current to the retentate), as opposed to static counter pressure, allowed lower overall fouling, a longer time of operation and better protein recovery because of more evenly distributed fouling along the membrane tube.
01 Jul 1993
TL;DR: In this paper, a new mathematical model of fouling was developed, which is based on the physics and/or chemistry of the fouling process, and the value of the asymptotic fouling-factor was predicted satisfactorily with the help of the model for fouling.
Abstract: The mechanism of fouling of heat-transfer surfaces by crystallization and sedimentation from a flowing liquid was studied by performing tests under carefully-controlled conditions. A new mathematical model of fouling was developed, which is based on the physics and/or chemistry of the fouling process. Predictions of this model are in good agreement with the experiments which were carried out with aqueous calcium-sulfate solutions and aqueous kieselguhr suspensions. The effects of the rate of flow, concentration, and temperature on fouling were studied. The measured data were used to calculate the fouling factor. The fouling factor, as a function of time, approaches an asymptotic limit that depends essentially on the rate of flow. The value of the asymptotic fouling-factor was predicted satisfactorily with the help of the model for fouling.
TL;DR: This work shows that studies which rely on bacterial surface charge and cell surface hydrophobicity to describe membrane surface fouling overlook bacterial surface interactions which control cake stability.
TL;DR: In this paper, the authors investigated the various models and mechanisms of scale formation and biofouling processes in water desalination plants and discussed proper pretreatment methods and scale control techniques to minimize the drastic effects on the performance of desalification plants in Saudia Arabia.
TL;DR: The hardness and size of the deposit is a function of fly-ash chemistry and fluid dynamics as discussed by the authors, and it can adhere to the wall if an improper soot blowing design is chosen, and metal sulfides along with fluoride and chloride compounds have been identified on the water wall and on the outer surfaces of the flyash particles.
Journal Article•
TL;DR: A state-of-the-art process in the San Ardo oil field converted produced brine into freshwater as mentioned in this paper, using chemical clarification, softening, filtration, and reverse osmosis (RO).
Abstract: A state-of-the-art process in the San Ardo oil field converted produced brine into freshwater. The conversion process used chemical clarification, softening, filtration, and reverse osmosis (RO). After extensive testing resolved RO membrane fouling problems, the pilot plant successfully handled water with about 7,000 mg/l. of total dissolved solids, 250 mg/l. silica, and 170 mg/l. soluble oil. The treated water complies with the stringent California drinking water standard. The paper describes water reclamation, the San Ardo process, stability, reverse osmosis membrane fouling, membranes at high pH, water quality, and costs.
TL;DR: The zebra mussel, Dreissena polymorpha, and its rapid spread in North America, makes it probably the most economically important fouling organism in freshwaters at the present time.
Abstract: Adsorption of a “conditioning”; film precedes the development of communities typically dominated by diatom slimes, filamentous algae or invertebrates. The type and extent of fouling is often specific to a particular location, being influenced by water chemistry, eutrophication and whether any local control measures are employed. The zebra mussel, Dreissena polymorpha, and its rapid spread in North America, makes it probably the most economically important fouling organism in freshwaters at the present time. The types of fouling control measures in current use and future developments are discussed.
01 Jan 1993
TL;DR: A review with many refs. as mentioned in this paper covers the causes and mechanisms of the fouling of reverse osmosis (RO) membranes in water purifn. systems, including inorg. deposits (scaling), org. adsorption (org. fouling), particulate deposition (colloidal fouling) and microbial adhesion and growth (biofouling).
Abstract: A review with many refs. covers the causes and mechanisms of the fouling of reverse osmosis (RO) membranes in water purifn. systems, including inorg. deposits (scaling), org. mols. adsorption (org. fouling), particulate deposition (colloidal fouling), and microbial adhesion and growth (biofouling), with emphasis on biofouling and interactions between the various types of fouling. General principles for biofouling prevention are also discussed.
Journal Article•
Journal Article•
TL;DR: This paper measured adsorption spectra in reflective mode to determine the extent of protein fouling on ultra-filtration membranes and showed that it is possible to detect the presence of proteins in ultrafiltration membrane.
Abstract: Measuring adsorption spectra in reflective mode provides fast and easy determination of the extent of protein fouling on ultrafiltration membranes
TL;DR: In this article, the physical, chemical and biological aspects of HX corrosion were analyzed using electrochemical and surface characterization techniques, and the results indicated that microorganisms play an important role in the degradation process.
01 Oct 1993
TL;DR: In this article, the suitability of a reaction kinetic fouling model for fouling of heat exchanger surfaces by whole milk was investigated for estimation of the relative deposit distribution in heat treatment equipment for temperatures up to 115·C.
Abstract: The suitability of a reaction kinetic fouling model was investigated for fouling of heat exchanger surfaces by whole milk. Experiments were carried out on a plate heat exchanger by applying different temperature-time combinations in the temperature range from 70 to 130·C. The denaturation of whey proteins was measured by high performance gel permeation chromatography and the amount and composition of deposits on the plates of the heat exchanger was determined. The kinetic fouling model tumed out to be valid for estimations of the relative deposit distribution in heat treatment equipment for temperatures up to 115·C. The absolute fouling level increased strongIy with aging of the milk.
TL;DR: In this article, the deposition of coke-like products was studied in the postcracking zone ( < 500°C) of a laboratory pyrolysis reactor coupled with a thermobalance.
TL;DR: In this article, a combined corrosion and fouling instrument is proposed to provide a real-time indication of corrosion activity under heat transfer conditions at the tube-wall surface, and the results obtained from recent trials are presented and discussed.