Mechanism of Calcium Carbonate Scale Deposition on Heat-Transfer Surfaces

Hasson, David; Avriel, Mordecai; Resnick, William; Rozenman, T.; Windreich, Shlomo

doi:10.1021/i160025a011

Cited by 165 publications

(68 citation statements)

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“…Dawe and Zhang 34 showed that the plot of crystal size against time gives a straight line and the calcite layer growth rate can be determined from the slope of this straight line. Hasson et al 35 also measured the rate of scale growth under the condition such that the scale layers grow linearly with time. The surface growth rates for SR 10, 15, 25, 45, and 60 were determined by a linear fit after the induction period in the plot of average size of crystals versus time [ Fig.…”

Section: Surface Growth Rate At Constant Saturation Ratiomentioning

confidence: 99%

Development of a novel once-through flow visualization technique for kinetic study of bulk and surface scaling

Sanni

Bukuaghangin

Huggan

et al. 2017

Review of Scientific Instruments

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There is a considerable interest to investigate surface crystallization in order to have a full mechanistic understanding of how layers of sparingly soluble salts (scale) build on component surfaces. Despite much recent attention, a suitable methodology to improve on the understanding of the precipitation/deposition systems to enable the construction of an accurate surface deposition kinetic model is still needed. In this work, an experimental flow rig and associated methodology to study mineral scale deposition is developed. The once-through flow rig allows us to follow mineral scale precipitation and surface deposition in situ and in real time. The rig enables us to assess the effects of various parameters such as brine chemistry and scaling indices, temperature, flow rates, and scale inhibitor concentrations on scaling kinetics. Calcium carbonate (CaCO3) scaling at different values of the saturation ratio (SR) is evaluated using image analysis procedures that enable the assessment of surface coverage, nucleation, and growth of the particles with time. The result for turbidity values measured in the flow cell is zero for all the SR considered. The residence time from the mixing point to the sample is shorter than the induction time for bulk precipitation; therefore, there are no crystals in the bulk solution as the flow passes through the sample. The study shows that surface scaling is not always a result of pre-precipitated crystals in the bulk solution. The technique enables both precipitation and surface deposition of scale to be decoupled and for the surface deposition process to be studied in real time and assessed under constant condition.

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Section: Surface Growth Rate At Constant Saturation Ratiomentioning

confidence: 99%

Development of a novel once-through flow visualization technique for kinetic study of bulk and surface scaling

Sanni

Bukuaghangin

Huggan

et al. 2017

Review of Scientific Instruments

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“…Time delay Figure 6: Concentration and temperature profiles at the heat transfer surface [15] The second step is the accumulation of these transported species on the crystal layer at the heated surface as a result of concentration difference between the solid-liquid surface (C i ) and the saturation concentration (C s ).. The deposit rate from the reaction process can be calculated as follows:…”

Section: Deposit Ratementioning

confidence: 99%

“…If the reaction mechanism is assumed to be the controlled mechanism, then equation (3) can be used to describe the deposit rate in heated surface areas at appropriate surface temperature and species concentration. The concentration driving force in equation (3) has been described by Hasson et al [18] based on the concentrations and the solubility product K sp of calcium carbonate and the reaction order of the formation of calcium carbonate was assumed as first order reaction (n = 1) as reported by Hasson et al [15].…”

Section: Deposit Ratementioning

confidence: 99%

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Dynamic modelling of Heat Exchanger fouling in multistage flash (MSF) desalination

Alsadaie

Mujtaba

2017

Desalination

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Fouling on heat transfer surfaces due to scale formation is the most concerned item in thermal desalination industry. Here, a dynamic fouling model is developed and incorporated into the MSF dynamic process model to predict fouling at high temperature and high velocity. The proposed dynamic model considers the attachment and removal mechanisms in the fouling phenomena with more relaxation of the assumptions such as the density of the fouling layer and salinity of the recycle brine. While calcium sulphate might precipitate at very high temperature, only the crystallization of calcium carbonate and magnesium hydroxide are considered in this work. Though the model is applied in a 24 stages brine recycle MSF plant, only the heat recovery section (21 stages) is considered under this study. The effect of flow velocity and surface temperature are investigated. By including both diffusion and reaction mechanism in the fouling model, the results of the fouling prediction model are in good agreement with most recent studies in the literature. The deposition of magnesium hydroxide increases with the increase in surface temperature and flow velocity while calcium carbonate deposition increases with the increase in the surface temperature and decreases with the increase in the flow velocity.

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“…Processes of carbonate scale deposition on condenser heat-exchange surfaces (CHS) from oversaturated solutions of recirculating water of the closed-circuit cooling system (CCS) can be theoretically divided into several stages, separation of which is found quite impossible [5][6][7][8][9]. Increase of deposit amount in local overheating areas causes corrosion damages of the heat-exchange surfaces and can result in necessity to perform expensive works on repair and even replacement of a steam generator.…”

Section: Introductionmentioning

confidence: 99%

Performance of the Nuclear Power Plant Condensing Unit

Pavelyev

Лавриненко

2016

MATEC Web Conf.

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Abstract. In the article the analysis of the modernization of the condensing unit. Thermal calculations and design of the condensing unit of the Kalininskaya nuclear power plant was conducted. Extension of service life of the operating NPP power units is one of the most important tendencies of the modern stage of nuclear power engineering development and the most efficient funds investment for preserving generating capacities. The data indicate when modernizing the condensing unit, its cooling area was increased for about 4,000 m 2 due to increasing number of tubes. In addition, tube geometrical dimensions were changed; the wall thickness was reduced from 1 and 2 mm to 0.7 and 1.25 mm respectively.

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Mechanism of Calcium Carbonate Scale Deposition on Heat-Transfer Surfaces

Cited by 165 publications

References 1 publication

Development of a novel once-through flow visualization technique for kinetic study of bulk and surface scaling

Development of a novel once-through flow visualization technique for kinetic study of bulk and surface scaling

Dynamic modelling of Heat Exchanger fouling in multistage flash (MSF) desalination

Performance of the Nuclear Power Plant Condensing Unit

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