Calcium Carbonate Scale Formation Research Articles

Effect of high-frequency electric fields on calcium carbonate scaling

The present study conducted an investigation on the effect of high-frequency electric fields (HFEF) in calcium carbonate (CaCO 3) scale formation on heated copper tube surfaces. Artificial hard water at varying CaCO 3 hardness was used. Calcium carbonate scales were formed on a heated copper tube surface, the fouling thermal resistance was calculated, and the calcium content of the deposited CaCO 3 scale was measured by an inductively coupled plasma mass spectroscopy (ICP-MS), and the cooling water was analyzed during the scaling process. No-treatment and HFEF-treatment cases were conducted and compared. The calcium content of the deposited scale dropped by 4–49% in HFEF-treatment case. The lower calcium content of the deposit corresponded to thinner deposits. Water analyses showed consistently lesser percentage drop in HFEF-treatment case primarily due to less fouling deposition. The asymptotic fouling thermal resistance in HFEF-treatment case had a maximum decrease of 88% (i.e., from 4.5 × 10 − 4 to 5.4 × 10 − 5 m 2K/W).

Effect of Various Cations on the Formation of Calcium Carbonate and Barium Sulfate Scale with and without Scale Inhibitors

High pressure dynamic tube blocking tests have been conducted to determine the effect of iron (divalent and trivalent), calcium, magnesium, and sodium ions on the formation of calcium carbonate and barium sulfate scale with and without added scale inhibitors. Scale inhibitors were chosen to represent the three main functional groups used in commercial oilfield scale inhibitors: the phosphonate group (found in sodium diethylenetriaminepentaphosphonate), the carboxylate group (in sodium polyaspartate), and the sulfonate group (in sodium polyvinysulfonate). A fourth proprietary inhibitor with phosphonate and carboxylate groups was also used in some studies.

Evaluation of synthesized antiscalants for cooling water system application

Mineral scales are formed in cooling water systems and they cause heat transfer problems. This study has been carried out to reduce the carbonate and sulphate scales of calcium. To inhibit the scale formation in cooling water systems, polyacrylic acid was synthesized, characterized and the ability of the polymer to mitigate the calcium carbonate and calcium sulphate scale formation was tested through chemical screening and electrochemical impedance techniques. X-ray diffraction (XRD) and scanning electron microscope (SEM) studies were performed to understand the morphological changes of the scales in the presence of the polymer. The gelation and iron dispersion ability of the polymer were also noted. The synthesized polyacrylic acid was compared with the commercial product AQUASUPER B99, which is basically a polyacrylamide. It was observed that this polyacrylic acid could be used for the cooling water applications. Among the two inhibitors, polyacrylic acid shows slightly better antiscaling properties even at higher temperatures and pH for both CaCO 3 and CaSO 4 scales compared to the commercial product.

Gambier extracts as an inhibitor of calcium carbonate (CaCO 3) scale formation

The investigation of Gambier extracts ( Uncaria gambier Roxb leaves) as an inhibitor of calcium carbonate scale formation has been carried out using the bottle-roller batch method with the concentration of a growth solution ranging from 0.1 to 0.6 M and at the temperature of 80 °C. The data obtained shows that Gambier extracts inhibit the formation of calcium carbonate scale at the various concentrations of the growth solution. The ability of Gambier extracts as an inhibitor of the formation of calcium carbonate scale is around 40–100% in inhibiting the growth rate of CaCO 3 scale. This ability depends on the concentration of Gambier extracts added into the growth solution and the concentration of the growth solution as a growth media of CaCO 3 seed crystals.

THE ROLE OF C-METHYL-4,10,16,22-TETRAMETOXY CALIX[4]ARENE AS INHIBITOR OF CALCIUM CARBONATE (CaCO<sub>3</sub>) SCALE FORMATION

The role of C-methyl-4,10,16,22-tetrametoxy calix[4]arene as inhibitor of calcium carbonate scale formation has been investigated. The result shows that C-methyl-4,10,16,22-tetrametoxy calix[4]arene inhibits a formation of calcium carbobate crystals at a concentration of growth solution of 0.1 M. The ability of C-methyl-4,10,16,22-tetrametoxy calix[4]arene as inhibitor of the formation of calcium carbobate scale is 33-100% in inhibiting growth rate of CaCO3 scale formation. This ability depends on the concentration of C-methyl-4,10,16,22-tetrametoxy calix[4]arene added into growth solution. However, the addition of C-methyl-4,10,16,22-tetrametoxy calix[4]arene at a range of 10-100 ppm is a much enough in inhibiting the growth rate of CaCO3 crystals. Keywords: tetrametoxycalixarene, CaCO3, inhibitor

Investigation of Scale Mitigation and Sequestering Properties of Some Polyelectrolytes

Formation of mineral scales poses significant problem in cooling water system. Fouling and scaling on heat transfer surface reduces the efficiency of heat exchangers. The design of heat exchangers takes into account the decrease of heat transfer by increasing the heat transfer area. The water soluble polyelectrolyte of maleic acid and acrylic acid was synthesized for testing of their antiscaling and sequestering properties. The characterization of these polyelectrolytes was done by measuring the viscosity and through FTIR analysis. Antiscaling properties of polymaleic acid and sequestering capacity of polyacrylic acid were studied at different concentrations from 100–500 ppm and temperatures from 60–80°C. It was found that the polymaleic acid showed good inhibition efficacy, i.e., 88.95% at 60°C and the 500 ppm concentration for calcium carbonate scale formation, while the sequestering capacity of the polyacrylic acid was 327.50 at 100 ppm concentration and at 60°C. These results were confirmed by measuring the conductivity of the solution.

Low‐phosphorus maleic acid and sodium ρ‐styrenesulfonate copolymer as calcium carbonate scale inhibitor

AbstractIn this article, a multifunctional and environment‐friendly agent for industry circulation cooling water, maleic acid and sodium ρ‐styrenesulfonate copolymer containing low‐phosphorus was synthesized in aqueous solution with hypophosphorous acid/hydrogen peroxide as redox initiators. The effects of monomer feed ratio, temperature, dose of hypophosphorous acid, and drop speed of hydrogen peroxide on calcium carbonate inhibition were investigated, and the experimental conditions were optimized using orthogonal method. The composition and structure of the copolymer were analyzed by enery‐dispersive X‐ray analysis, fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. The results of the static scale inhibition tests showed that the copolymer was effective in inhibiting the formation of calcium carbonate scale. The calcium carbonate precipitates formed in the static tests were examined by scanning electronic microscopy and X‐ray diffraction spectra. The results indicate that in the presence of the copolymer the calcium carbonate precipitate is the mixture of calcite and vaterite that could be stabilized kinetically in the presence of the copolymer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Corrosion control by using indirect methods

The corrosion or deposition effect from Paradeisos well water, in the municipality of Hrysoypolis in Greece, was studied. Indices were monitored and calculated based on the principle of calcium carbonate deposition. The relative state of saturation with respect to calcium carbonate has been determined by physical means, using the marble test and controlling the change in pH and total alkalinity before and after the saturation with CaCO 3. The Langelier saturation index (LSI) was calculated, as a purely equilibrium index that deals only with the thermodynamic driving force for calcium carbonate scale formation and growth. Also the Larson Ratio was calculated. The interaction and relationship between the pipe materials and water were discussed. The indices demonstrate that the potable water of Municipality Hrysoypolis is not corrosive and does not cause damage in the work of water supply. At the same time, the water has the tendency to form a protective layer in the pipes.

ステンレス鋼表面への炭酸カルシウムスケールの付着生成機構

ステンレス鋼表面への炭酸カルシウムスケールの付着生成機構

Influence of [formula omitted] on [formula omitted] formation—bulk precipitation and surface deposition

The formation of CaCO3 mineral scale is a persistent and expensive problem in oil and gas production. The magnesium ion, present in formation and injection waters in downhole conditions, is a key determinant in CaCO3 scale formation. In the work reported herein, the kinetics of calcium carbonate scale formation is studied both in the bulk solution and on a metal surface. The effect of the Mg2+ ion on the scale formed on the metal surface has been studied systematically in this paper including aspects of the kinetics, morphology, and Mg/Ca ratio of the deposit on the metal surface. The Mg2+ ion adsorbs onto the deposited crystals and the ratio of Mg2+ in the deposit formed on the metal surface is proportional to the ratio of Mg/Ca in the scaling water. The distribution coefficient in surface deposition and in bulk solution is a constant and independent of the concentration of Mg2+ ions in the bulk solution. Simultaneously, the Mg2+ ion accelerates the crystal transformation from vaterite to calcite and adsorbs on the surface of vaterite and calcite causing an increase in surface roughness in addition to distortion of crystals.

Water soluble copolymers for calcium carbonate and calcium sulphate scale control in cooling water systems

AbstractMineral scales are formed in cooling water systems and they cause heat transfer problems. Much research has been carried out to reduce the carbonate and sulphate scales of calcium. To inhibit the scale formation in cooling water systems, vinyl acetate–acrylic acid (VA–AA) and vinyl acetate– methacrylic acid (VA–MAA) copolymers were synthesized, characterized, and the ability of the polymers to mitigate the calcium carbonate and calcium sulphate scale formation was tested through chemical screening, constant potential electrolysis, and electrochemical impedance techniques. XRD (X‐ray diffraction) and SEM (scanning electron microscope) studies were performed to understand the morphological changes of the scales in the presence of the polymers. The biocidal, gelation, and iron dispersion ability of the polymers were also noted. Among the two threshold inhibitors, VA–AA shows slightly better antiscaling properties even at higher temperatures and pH for both CaCO3 and CaSO4 scales compared to the methacrylic copolymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1451–1459, 2005

An improved predictive correlation for the induction time of CaCO 3 scale formation during flow in porous media

The induction time, t ind , of calcium carbonate precipitation in porous rocks was experimentally measured under dynamic conditions at temperatures from 25 to 120 °C with the use of a radiotracer technique, where the gamma-emitting nuclide 47Ca was used as a tracer in order to monitor the scale deposition at real time. Based upon nucleation theory and experimental observations, the following improved correlation is proposed: log t ind ( min ) = 3.2 − 3.0 SI − 959.8 T + 1849.9 SI T . This equation predicts satisfactorily the induction time of calcium carbonate scale formation under specific dynamic (flow) conditions in the near-well region ( T is the absolute temperature in K, and SI is the saturation index, SI = log SR , where SR is the saturation ratio).

Influence of PPCA inhibitor on CaCO3 scale surface deposition and bulk precipitation at elevated temperature

Abstract Scale formation is a serious and costly problem encountered in the oil and gas industry. Polyphosphinocarboxylic acid (PPCA) is a common commercial organic scale inhibitor used in the oil and gas industry which is normally referred to a nucleation inhibitor. In this paper, the effect of PPCA on calcium carbonate scale is studied systematically and some new insights into the mechanisms of PPCA inhibition are given. Traditionally, the studies of scale formation and inhibition have focused on bulk precipitation or surface deposition. Few studies have focused on the difference between surface deposition and bulk precipitation processes. In this paper, the effect of PPCA inhibitor on calcium carbonate scale formation is studied both in the bulk solution and on the metal surface in supersaturated scale formation solutions which represent typical waters encountered in oil and gas production. It is clear that PPCA inhibits both bulk precipitation and surface deposition but to a different degree. At 4 ppm...

Calcium carbonate scale formation and control

This paper focuses on the complex problem of calcium carbonate scale formation on heated surfaces and the possibilities of controlling or reducing this problem. The development of scale is a multistage process and is affected by a number of factors, these include supersaturation, pH, temperature and flow velocity. Calcium carbonate deposition can be ameliorated by chemical, physical or biological methods with various level of effectiveness. These controls can be divided into three main categories: those that affect solubility, those that alter the growth mechanism of crystals, and those that change the potential of a surface to foul. One of the most effective methods of controlling crystallization fouling is the addition of chemical inhibitors to potentially scaling waters. There are a number of alternative non-chemical treatment options available, amongst these are the use of magnetic, electronic and electrolytic treatment devices. Scale formation is affected by the physical nature of the material on which it is forming, therefore it is possible to choose material to reduce scale formation. Each of these scale controlling methods has their advantages and a number of factors have to be considered before choosing the right option.

Real-Time and In-Situ Detection of Calcium Carbonate Scale in a West Texas Oil Field

Summary A novel technique has been developed to detect the onset and increase of calcium carbonate scale deposition from oilfield production fluids. This method uses an attenuated total reflectance (ATR) probe, called the scale sensor, to detect scale formation in situ. Because this method is based on existing technology and requires little supporting equipment, a simple, cost-effective monitoring device could be placed in many locations within a production system. This method could provide a system-wide, in-situ, real-time response to calcium carbonate scale formation at its earliest stages. As a first step toward evaluating the effectiveness of this new technology, the scale sensor was field tested at a west Texas oil field. The scale sensor was observed to detect the deposition of calcium carbonate under static and flowing conditions in actual produced fluids. In the static tests, crude oil, suspended solids, and other endogenous materials did not affect the scale sensor's response. Under flowing conditions, like those found in the production flowlines at this west Texas oil field, scale sensor response was observed to correlate to the chemical injection rate of both the scale inhibitor and the dispersant. On the basis of the results from the scale sensor, the scale inhibitor's injection point will soon be moved to the wellhead.

Development of acrylonitrile copolymers for scale control in cooling water systems

The formation of calcium sulphate and carbonate scale has been prevented by using acrylonitrile-acrylic acid (AN-AA) and acrylonitrile-methacrylic acid (AN-MAA) copolymers over a temperature range of 50–80°C at different pHs from 7.0 to 8.5. The efficiency of the antiscalants was assessed by various techniques such as a chemical screening test, constant potential electrolysis and impedance measurements. The change in crystal habits by the addition of antiscalant was seen using XRD spectrum and SEM photographs. The effectiveness of polymers on microorganisms and forming gelation with calcium ion and iron-dispersing ability were also studied. The amount of scale deposition increased with increase in temperature and pH. The polymers acted as good antiscalants at low temperature and pH ranges. They also acted as good flocculants under some special conditions. For example, at a higher pH of 8.5 and temperature 80°C with 20 ppm dosage level of the AN-AA polymer, 100% was achieved. Further, they had good iron dispersibility and can gelate with Ca 2+ ions.

Calcium carbonate scale control, effect of material and inhibitors

This paper focuses on developing a reproducible method for reducing calcium carbonate scale formation on heated surfaces where scaling can cause serious problems. It is known that calcium carbonate precipitation is sensitive to impurity ions, such as iron and zinc, even at trace concentration levels. In this paper two sets of experiments are reported. The first experiments were undertaken to investigate the effect of zinc, copper and iron dosing on CaCO3 nucleation and precipitation. Results from the experiments showed that the most effective inhibitor of CaCO3 precipitation was zinc and the effect was linked to dose levels and temperature. Copper and iron had little effect on precipitation in the dose range investigated. The second trial was undertaken to translate the precipitation data to scale formation. These tests were undertaken at 70 degrees C. 5 mg x L(-1) zinc dose reduced the scale formation by 35%. The effect of iron on calcium carbonate scaling rate was not significant. The physical nature of the material on which the scale is formed also influences the scaling. The scaling experiment was also used to investigate the effect of different surface material (stainless steel, copper and aluminium) on CaCO3 scale formation. Copper surface scaled the most.

The effect of temperature and pressure on oilfield scale formation

Dynamic tube blocking tests have been conducted to determine the effect of increasing temperature and pressure on barium sulphate and calcium carbonate scale formation, as part of a study considering the application of scale inhibitors in high pressure and high temperature reservoirs. As pressure was increased, the scaling tendency of the carbonate and sulphate scaling brines tested was found to decrease, as was predicted by scale prediction software. As temperature was increased, the scaling tendency of the carbonate scaling brine increased, whereas that of the high sulphate scaling brine system was found to decrease. The effect of temperature on scaling tendency was more significant than that of pressure. A low sulphate scaling brine was also tested and this failed to precipitate scale during the tests at the lowest temperature (50 °C), although at this lowest temperature, it was predicted to have the highest scaling tendency. Under these test conditions, the kinetic rate of scale precipitation was low, so the kinetic rate of precipitation became more significant relative to the thermodynamic drive for precipitation.

Static/Dynamic Evaluation of Calcium Carbonate Scale Formation and Inhibition

This article is a synopsis of paper SPE 68963, "Static and Dynamic Evaluation of Calcium Carbonate Scale Formation and Inhibition," by N. Kohler, SPE, G. Courbin, and F. Ropital, Inst. Francais du Petrole, originally presented at the 2001 SPE European Formation Damage Conference, The Hague, 21-22 May.

The effect of ultrasonic field on calcium carbonate scale formation

A retardation effect (62–76%) was observed on the crystallization of calcium carbonate in the presence of an ultrasonic applied field (0.56 w/cm 2). The apparent order of crystal growth of calcite was found to be n=2±0.2 for the seeded growth experiments and n=6.7±0.2, n=5.3±0.1 for the spontaneously precipitated vaterite in the absence and presence of the ultrasonic field, respectively. The mechanism, the nature, the morphology and the size of the crystals formed was not influenced by the applied ultrasonic field, which may possibly affect the dehydration step of the growth units or the migration step of the dehydrated growth units to the active growth sites.