Calcium carbonate fouling on double-pipe heat exchanger with different heat exchanging surfaces

In the present study, the main influencing factors of crystallization fouling in electric water heating were investigated. Dependence on the saturation index and four operating parameters was analyzed, namely: liquid temperature, surface temperature, flow rate and electrical leakage current. A focus of the study was the influence of electrical leakage current on the fouling behavior and the morphology of the deposited crystal layers. The investigation shows that the aforementioned parameters influence the fouling process and crystal size growth in a different way. The experimental results were used to find a correlation between the electrical leakage current and induction time. In addition, a modeling approach is presented which allows an estimation of the fouling mass flux.

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“…Greenish brash oxide was not visible in these test series unlike in Teng et al. [24]. In the images of the brass bolt (Fig.…”

Section: Resultsmentioning

confidence: 50%

Analysis of crystallization fouling in electric water heating

Janzen

Kenig

2019

Heliyon

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“…The predictions were obtained for k sl =0.3, 0.6 and 1.0 W/m/K, while the other parameters were the same as listed in this section, except for T m,i =57 o C and T a =40 o C. All the resulting graphs shown in Fig. 3 have one point in common, namely the point corresponding to the zerothickness of the sludge layers, which occurs at about T m,o =46.16 o C. The sludge on the exchanger walls is an additional thermal resistance, which results in a lower heat exchange and an increase in the return temperature from the heat exchanger [20][21][22]. The increase in the value of the heat transfer coefficient of the sludge, which depends on the type of substrate, causes an increase in heat exchange and a drop in the return temperature from the heat exchanger.…”

Section: Experimental Data and Calculation Resultsmentioning

confidence: 97%

Determining the thickness of sludge on the heat exchanger tube inside an anaerobic digester

Hożejowski

Teleszewski

2019

EPJ Web Conf.

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The paper presents a simplified method of determining the thickness of sludge on the walls of the heat exchanger piping in a biogas plant digester. The evaluation of the thickness of a sludge layer is based on the biogas plant operation parameters, including the inlet and outlet temperature of the heat exchanger, mass flow and the geometric characteristics of the heat exchanger and physical parameters of the substrate working inside a fermentation chamber. Measurement of the thickness of the sludge layer on the walls of a heat exchanger is only possible at the time of general cleaning of a digester, which necessitates switching off the biogas plant operation. The paper compares the results of predictions with experimental data of the work of a biogas plant digester located in north-eastern Poland, in Ryboły. The presentation of the obtained numerical results is supplemented by the uncertainty analysis. The significance of undertaking such research lies in its applicational aspects, as during the operation of a biogas plant sludge accumulates on the walls of a digester, which provides additional thermal resistance and reduces the thermal efficiency of the heat exchanger.

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“…Where v represents the scale inhibition rate; 1 , 2 is the scale thickness of heat exchanger A and scale thickness of heat exchanger B, respectively. Fouling resistance R f (m 2 KW -1 )on the surface of the plate heat exchanger, which can be defined as formula (7) [24][25] :…”

Section: Test Proceduresmentioning

confidence: 99%

“…Scale species differs from depending on the treatment method and mineral content of the utilized water. Among them, the most common mineral ions are Ca 2+ and Mg 2+ [2] . When the hard water flows through the heat transfer equipment, these ions and bicarbonate ions precipitate due to changes in pressure and solubility,, eventually forming mineral deposits(limescale) on the heat transfer surface.…”

Section: Introductionmentioning

confidence: 99%

Physical Water Treatment using Alternating Variable Frequency Electric Field Device for the Mitigation of Limescale in Industrial Production.

Zhang¹,

Cao²,

Wang³

et al. 2021

Preprint

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Electric field scale inhibition is one of the most promising methods of scale inhibition. In this study, an alternating variable frequency electric field device is presented, it able to prevent the growth of scale in industrial heat exchange equipment effectively. Conduct field test at the heat exchange station to analyze the scale inhibition performance of the device. The test results showed that after using alternating variable frequency electric field device, the scale thickness on the heat exchange surface is significantly reduced, fouling resistance reduced by more than 58%, and the anti-corrosion rate for Fe element content reaches 19.78%, The SEM image of the scale changes from a dense irregular sharp shape to a loose spherical shape. Conclusively, alternating variable frequency electric field device has grate scale inhibition performance. This is of great significance to the field of heat transfer and energy saving.

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Calcium carbonate fouling on double-pipe heat exchanger with different heat exchanging surfaces

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Cited by 90 publications

References 41 publications

Analysis of crystallization fouling in electric water heating

Analysis of crystallization fouling in electric water heating

Determining the thickness of sludge on the heat exchanger tube inside an anaerobic digester

Physical Water Treatment using Alternating Variable Frequency Electric Field Device for the Mitigation of Limescale in Industrial Production.

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