Development and Use of a Micromanipulation Technique for Measuring the Force Required to Disrupt and Remove Fouling Deposits

Liu, W.; Christian, G.K.; Zhang, Zhibing; Fryer, P.J.

doi:10.1205/096030802321154790

Cited by 63 publications

(54 citation statements)

References 5 publications

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“…The aggregates grow in strength and size, while the fraction of native proteins decreases (Durand et al, 2002). These observations are, in principle, consistent with the observations of Liu et al (2002) on non-dairy product and Wilson (2005) on a general discussion who suggested that increasing the heating time results in increasing the yield and the deposit hardness due to the deposit structural changes. Regardless of the 'structural consolidation', the accumulation of deposit on the heat transfer surface should lead, in any case, to greater thermal resistance hence the overall heat transfer reduction shown Figure 7.…”

Section: The Effect Of Heating/run Time On Whey Protein Solution Foulingsupporting

confidence: 87%

“…It was early documented by Epstein in 1983 as one of the principal mechanistic stages in the fouling process. However, more recent studies have shown that aging facilitates longer reaction time between the fouling layer matrixes (Liu et al, 2002) and affects the fouling process resulting in a strong and firm fouling layer that is difficult to clean particularly when the fouling layer is aged for a long period (Wilson, 2005).…”

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confidence: 99%

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Influence of Run Time and Aging on Fouling and Cleaning of Whey Protein Deposits on Heat Exchanger Surface

Fickak¹,

Hatfield

Chen

2012

JFR

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In the cleaning operations of heat exchange surfaces in dairy processing plants, the effect of heating/run time (HT) and aging on the fouling/cleaning of heat exchangers is not well understood. Longer heating time of the same deposit is expected to result in the formation of stronger and perhaps more cleaning resistant deposit. In this study, the phenomenon of heating and aging on the formation and cleaning of dairy fouling is investigated using the heat induced whey protein gels (HIWPG) produced in laboratory. The processes were also investigated with the whey protein deposits formed in pilot-scale plant trails.The HIWPGs were produced in tubular capsules for various heating (or run) times (60, 120, 240, 1440 and 2880 min respectively) and then dissolved in aqueous sodium hydroxide (0.5 wt %). The heating process here would have been of 'pure' aging. The dissolution rate was calculated based on the previously established UV Spectrophotometer analysis. The structure and texture of the gels were analysed using Scanning Electron Microscope (SEM) and texture analyser. In the pilot-scale plant study, whey protein fouling layers were generated by recirculating whey protein solution (6 wt %) for various heating periods (30, 60, and 90 min respectively). The deposit layers were then removed by recirculating aqueous sodium hydroxide (0.5 wt %) and the cleaning efficiency was monitored in the form of the recovery of heat transfer coefficient while both fluid electric conductivity and turbidity were recorded as indications of cleaning completion. It was found that increasing the HIWPG heating time significantly increased the gel hardness and dissolution time, implicating the difficulty in cleaning. Similarly to these results on gels, increasing the pilot-scale plant heating/run time increased the extent of fouling. The fouling layer formed next to the metal surface experienced the longest period of aging and the slope of the heat transfer coefficient increase seen at the final cleaning stage is related to this aging effect. The rate of cleaning for deposits formed initially on the metal surface is lower indicating a 'pure' aging effect of the deposit near surface.

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Section: The Effect Of Heating/run Time On Whey Protein Solution Foulingsupporting

confidence: 87%

mentioning

confidence: 99%

Influence of Run Time and Aging on Fouling and Cleaning of Whey Protein Deposits on Heat Exchanger Surface

Fickak¹,

Hatfield

Chen

2012

JFR

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“…Ths combination of thickness measurement, in response to imposed stress, yields the deformation behaviour of the fouling layer and has been applied to soft layers of food materials by Chew et al (2004b). The data obtained correlated very well with the results from micro-manipulation reported for similar materials by Liu et al (2002). Figure 2(a) shows the flow rate-clearance profile obtained for the gauge employed in these studies for a pressure difference of 950 Pa applied to water; the accuracy in h is of order *10 pm.…”

Section: Fluid Dynamic Gaugingsupporting

confidence: 60%

A Method for Measuring the Strength of Scale Deposits on Heat Transfer Surfaces

Chew¹,

Paterson²,

Wilson³

et al. 2005

Dev. Chem. Eng. Mineral Process.

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“…In order to measure the cohesive strength, the gap between the bottom surface of the probe and the substrate with attached biomass was varied. Part of the biomass layer was removed and the corresponding force was measured, following a protocol described in Liu et al (2002).…”

Section: Micromanipulationmentioning

confidence: 99%

Characterisation of bacterial adhesion and removal in a flow chamber by micromanipulation measurements

2007

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Flow device analyses and micromanipulation were used to assess the adhesive and cohesive integrity of the immobilised bacterial populations (biomass) of Pseudomonas fluorescens, which were harvested at different growth times and applied to a substrate made of stainless steel subsequently accommodated in a specially designed flow chamber. After the biomass was exposed to a fluidic environment for a period of time, the biomass samples were removed from the flow chamber and the apparent adhesion and cohesion of the remaining biomass was measured using a micromanipulation technique. The surface area of the substrate covered by the biomass exposed to the fluid flow was monitored by a digital camera and then quantified by image analysis. The results indicate a strong correlation between micromanipulation measurements and flow chamber experiments. The micromanipulation data show that the apparent adhesive strength of the biomass increased with the growth time. Moreover, the apparent adhesive strength was found to be stronger than the bacterial cohesive strength. The data was used to interpret the removal behaviour of the biomass from the flow chamber. Using these techniques, specific mechanisms of biomass detachment from a surface and optimised cleaning strategies can be postulated.

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Development and Use of a Micromanipulation Technique for Measuring the Force Required to Disrupt and Remove Fouling Deposits

Cited by 63 publications

References 5 publications

Influence of Run Time and Aging on Fouling and Cleaning of Whey Protein Deposits on Heat Exchanger Surface

Influence of Run Time and Aging on Fouling and Cleaning of Whey Protein Deposits on Heat Exchanger Surface

A Method for Measuring the Strength of Scale Deposits on Heat Transfer Surfaces

Characterisation of bacterial adhesion and removal in a flow chamber by micromanipulation measurements

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