Prediction of the calcium carbonate saturation pH in cooling water

McGaughey, Larry M.; Matson, Jack V.

doi:10.1016/0043-1354(80)90108-6

Cited by 7 publications

(5 citation statements)

References 4 publications

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“…LSI, which is also called saturation index, is usually used to predict the scaling tendency of water 23,24 and can be calculated by the following formula.

L . S . I goodbreak= italicpH goodbreak- italicpHs,

where pH is the practical value and pHs is the pH value of solution saturated with calcium carbonate saturation, and it can be expressed as

italicpHs goodbreak= ((), 9.7 goodbreak+ A goodbreak+ B) goodbreak- ((), C goodbreak+ D),

where A , B , C , and D are total dissolved solid coefficient, temperature coefficient, calcium hardness coefficient, and total alkalinity coefficient, respectively.…”

Section: Resultsmentioning

confidence: 99%

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An investigation on scaling failure of heat exchanger in cooling water system of natural gas purification plant

Jiang

Huang

Wang

et al. 2022

Asia-Pacific J Chem Eng

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In this study, a natural gas purification plant adopts open circulating water system, which cannot work properly and hinder the normal production of natural gas due to the problems such as scaling and blockage in the operation of heat exchanger device was reported. Qualities of the make‐up water and recirculating cooling water were evaluated by parameters such as hardness, alkalinity, pH, and conductivity. X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and optical microscope were employed to study the crystal structure, composition, and morphology of the scale deposits. The flow rate of the water in the tube bundle was calculated according to the design scale of these exchangers. The Langelier Saturation Index (LSI) was used to analyze the scale tendency of the cooling water system. The scale inhibition performance of the inhibitor was verified by static inhibition method. Results show that the scale mainly contains calcium carbonate, and the quality of circulating water is reasonably controlled with a proper range. However, there are three units sharing one cooling water system, of which the flow rate cannot be adjusted according to the actual heat load. The calculation results confirmed that the circulating water velocity in the tube bundle did not exceed 0.9 m/s. Although the scale inhibitor has a scale inhibition efficiency of more than 90% for the simulated circulating water at 80°C, the LSI analysis results showed that the high local temperature on the surface of the tube bundle caused by the low flow rate of water will increase the scaling tendency of the heat exchanger. Furthermore, the untimely injection of the inhibitor in the daily management and operation also greatly increased the risk of system scaling. This paper proves that the scaling of circulating water heat exchanger in the purification plant is mainly caused by device design and poor daily management. In order to prevent future failures, potential solutions and mitigation strategies were put forward.

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“…LSI, which is also called saturation index, is usually used to predict the scaling tendency of water 23,24 and can be calculated by the following formula.

L . S . I goodbreak= italicpH goodbreak- italicpHs,

where pH is the practical value and pHs is the pH value of solution saturated with calcium carbonate saturation, and it can be expressed as

italicpHs goodbreak= ((), 9.7 goodbreak+ A goodbreak+ B) goodbreak- ((), C goodbreak+ D),

where A , B , C , and D are total dissolved solid coefficient, temperature coefficient, calcium hardness coefficient, and total alkalinity coefficient, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…LSI, which is also called saturation index, is usually used to predict the scaling tendency of water 23,24 and can be calculated by the following formula.…”

Section: Langelier Saturation Index (Lsi) Analysismentioning

confidence: 99%

An investigation on scaling failure of heat exchanger in cooling water system of natural gas purification plant

Jiang

Huang

Wang

et al. 2022

Asia-Pacific J Chem Eng

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“…In this study, the width of calcite crystallization metastable zone was investigated by determining the critical pH of the crystallization system [15][16][17] jacketed crystallizer at different temperatures. Moreover, molecular simulation was used to investigate the adsorption behavior of 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) on calcite surfaces.…”

Section: Introductionmentioning

confidence: 99%

Molecular simulations and critical pH studies for the interactions between 2-phosphonobutane-1,2,4-tricarboxylic acid and calcite surfaces in circular cooling water systems

Jiaomei

Zhao

2014

Desalination and Water Treatment

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2014): Molecular simulations and critical pH studies for the interactions between 2-phosphonobutane-1,2,4-tricarboxylic acid and calcite surfaces in circular cooling water systems, Desalination and Water Treatment,The adsorption of 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) on calcite surfaces (1 1 0), (1 0 2), (1 0 4), (1 1 3), (2 0 2) was studied by molecular simulation. The phosphoric acid and carboxylic acid functional groups energetically interacted with the faces and preferentially occupied the carbonate ion sites by chemisorption, which is in agreement with the critical pH experiments. The strength of adsorption followed the order of (1 1 0) > (1 1 3) > (1 0 2) > (2 0 2) > (1 0 4). The binding energy gradually decreased with increasing temperature. The relationship between the critical pH and the adsorbed PBTC 2− configuration indicates that the adsorbed inhibitor configuration plays an important role in inhibitor efficiency.

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“…Deposition (scaling) of the minerals on heat exchanger, pipe, and reactor surfaces can lead to myriad serious problems, including loss of heat transfer efficiency, clogging of filters, obstruction of flow, localized corrosion attacks, excessive wear of metal parts, unscheduled shutdowns, and, ultimately, system failure. Over the last century, saturation and scaling indices, from the Langelier saturation index (LSI) to the Puckorius scaling index (PSI), were developed and constantly modified to predict the behavior of calcium carbonates (in some cases, calcium phosphates as well), in an effort to protect water distribution systems from mineral scaling and corrosion. − However, these equilibrium-based indices have been demonstrated to be of limited utility due to the inherent lack of kinetic considerations and inability to account for variations in water quality. − The ability of equilibrium-based indices to predict precipitation accurately for actual water systems is limited and often not validated through experimental observations.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Impedance Spectroscopy (EIS) Based Characterization of Mineral Deposition from Precipitation Reactions

Dzombak

Vidic

2012

Ind. Eng. Chem. Res.

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An accurate and convenient approach for monitoring the rate of mineral deposition on metals in real time was developed and involves use of an electrochemical cell employing the metallic collecting surface as a working electrode (WE). The WE serves as both the surface for mineral deposition and a sensor for probing subtle changes attributable to the growth of mineral deposits at the metal−mineral−water interface. The interfacial capacitance obtained from electrochemical impedance spectroscopy (EIS) was used as a measure of surface coverage by the mineral scale. Results show that a constant-phase element (CPE) capacitance correlated very well with the mass of mineral deposits accumulated on the metal surface. Moreover, the characteristics of different minerals evaluated in this study, i.e., calcium carbonate, calcium sulfate, and calcium phosphate, did not affect the CPE capacitance measurement significantly. Rather, the CPE capacitance was sensitive to small changes in the mineral mass deposited on the electrode (<0.1 mg). Unlike traditional methods for measurement of mineral deposition, the EIS allows in situ semicontinuous measurements of overall mineral deposition, and its sensitivity provides means for early detection of mineral deposition.

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Prediction of the calcium carbonate saturation pH in cooling water

Cited by 7 publications

References 4 publications

An investigation on scaling failure of heat exchanger in cooling water system of natural gas purification plant

An investigation on scaling failure of heat exchanger in cooling water system of natural gas purification plant

Molecular simulations and critical pH studies for the interactions between 2-phosphonobutane-1,2,4-tricarboxylic acid and calcite surfaces in circular cooling water systems

Electrochemical Impedance Spectroscopy (EIS) Based Characterization of Mineral Deposition from Precipitation Reactions

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